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Sample records for anticoagulant activated protein

  1. Anticoagulant synergism of heparin and activated protein C in vitro. Role of a novel anticoagulant mechanism of heparin, enhancement of inactivation of factor V by activated protein C.

    OpenAIRE

    Petäjä, J; Fernández, J. A.; Gruber, A.; Griffin, J H

    1997-01-01

    Interactions between standard heparin and the physiological anticoagulant plasma protein, activated protein C (APC) were studied. The ability of heparin to prolong the activated partial thromboplastin time and the factor Xa- one-stage clotting time of normal plasma was markedly enhanced by addition of purified APC to the assays. Experiments using purified clotting factors showed that heparin enhanced by fourfold the phospholipid-dependent inactivation of factor V by APC. In contrast to factor...

  2. Platelet factor 4 impairs the anticoagulant activity of activated protein C.

    LENUS (Irish Health Repository)

    Preston, Roger J S

    2012-02-01

    Platelet factor 4 (PF4) is an abundant platelet alpha-granule chemokine released following platelet activation. PF4 interacts with thrombomodulin and the gamma-carboxyglutamic acid (Gla) domain of protein C, thereby enhancing activated protein C (APC) generation by the thrombin-thrombomodulin complex. However, the protein C Gla domain not only mediates protein C activation in vivo, but also plays a critical role in modulating the diverse functional properties of APC once generated. In this study we demonstrate that PF4 significantly inhibits APC anti-coagulant activity. PF4 inhibited both protein S-dependent APC anticoagulant function in plasma and protein S-dependent factor Va (FVa) proteolysis 3- to 5-fold, demonstrating that PF4 impairs protein S cofactor enhancement of APC anticoagulant function. Using recombinant factor Va variants FVa-R506Q\\/R679Q and FVa-R306Q\\/R679Q, PF4 was shown to impair APC proteolysis of FVa at position Arg(306) by 3-fold both in the presence and absence of protein S. These data suggest that PF4 contributes to the poorly understood APC resistance phenotype associated with activated platelets. Finally, despite PF4 binding to the APC Gla domain, we show that APC in the presence of PF4 retains its ability to initiate PAR-1-mediated cytoprotective signaling. In summary, we propose that PF4 acts as a critical regulator of APC generation, but also differentially targets APC toward cytoprotective, rather than anticoagulant function at sites of vascular injury with concurrent platelet activation.

  3. Platelet factor 4 impairs the anticoagulant activity of activated protein C.

    LENUS (Irish Health Repository)

    Preston, Roger J S

    2009-02-27

    Platelet factor 4 (PF4) is an abundant platelet alpha-granule chemokine released following platelet activation. PF4 interacts with thrombomodulin and the gamma-carboxyglutamic acid (Gla) domain of protein C, thereby enhancing activated protein C (APC) generation by the thrombin-thrombomodulin complex. However, the protein C Gla domain not only mediates protein C activation in vivo, but also plays a critical role in modulating the diverse functional properties of APC once generated. In this study we demonstrate that PF4 significantly inhibits APC anti-coagulant activity. PF4 inhibited both protein S-dependent APC anticoagulant function in plasma and protein S-dependent factor Va (FVa) proteolysis 3- to 5-fold, demonstrating that PF4 impairs protein S cofactor enhancement of APC anticoagulant function. Using recombinant factor Va variants FVa-R506Q\\/R679Q and FVa-R306Q\\/R679Q, PF4 was shown to impair APC proteolysis of FVa at position Arg(306) by 3-fold both in the presence and absence of protein S. These data suggest that PF4 contributes to the poorly understood APC resistance phenotype associated with activated platelets. Finally, despite PF4 binding to the APC Gla domain, we show that APC in the presence of PF4 retains its ability to initiate PAR-1-mediated cytoprotective signaling. In summary, we propose that PF4 acts as a critical regulator of APC generation, but also differentially targets APC toward cytoprotective, rather than anticoagulant function at sites of vascular injury with concurrent platelet activation.

  4. The protein C omega-loop substitution Asn2Ile is associated with reduced protein C anticoagulant activity.

    LENUS (Irish Health Repository)

    Preston, Roger J S

    2012-02-01

    We report a kindred with heritable protein C (PC) deficiency in which two siblings with severe thrombosis showed a composite type I and IIb PC deficiency phenotype, identified using commercial PC assays (proband: PC antigen 42 u\\/dl, amidolytic activity 40 u\\/dl, anticoagulant activity 9 u\\/dl). The independent PROC nucleotide variations c.669C>A (predictive of Ser181Arg) and c.131C>T (predictive of Asn2Ile) segregated with the type I and type IIb PC deficiency phenotypes respectively, but co-segregated in the siblings with severe thrombosis. Soluble thrombomodulin (sTM)-mediated inhibition of plasma thrombin generation from an individual with PC-Asn2Ile was lower (endogenous thrombin potential (ETP) 56 +\\/- 1% that of ETP determined without sTM) than control plasma (ETP 15 +\\/- 2%) indicating reduced PC anticoagulant activity. Recombinant APC-Asn2Ile exhibited normal amidolytic activity but impaired anticoagulant activity. Protein S (PS)-dependent anticoagulant activity of recombinant APC-Asn2Ile and binding of recombinant APC-Asn2Ile to endothelial protein C receptor (EPCR) were reduced compared to recombinant wild-type APC. Asn2 lies within the omega-loop of the PC\\/APC Gla domain and this region is critical for calcium-induced folding and subsequent interactions with anionic phospholipids, EPCR and PS. The disruption of these interactions in this naturally-occurring PC variant highlights their collective importance in mediating APC anticoagulant activity in vivo.

  5. Acquired deficiencies of protein S. Protein S activity during oral anticoagulation, in liver disease, and in disseminated intravascular coagulation.

    OpenAIRE

    D'Angelo, A.; Vigano-D'Angelo, S; Esmon, C T; Comp, P C

    1988-01-01

    Protein S is a vitamin K-dependent plasma protein which serves as the cofactor for activated protein C. Protein S circulates in both an active, free form and in an inactive complex with C4b-binding protein. To elucidate the role of protein S in disease states and during oral anticoagulation, we developed a functional assay for protein S that permits evaluation of the distribution of protein S between free and bound forms and permits determination of the specific activity of the free protein S...

  6. Enhancement of rabbit protein S anticoagulant cofactor activity in vivo by modulation of the protein S C4B binding protein interaction.

    OpenAIRE

    Weinstein, R E; Walker, F. J.

    1990-01-01

    The carboxy-terminal region of protein S has been recently been observed to be involved in the interaction between protein S and C4b-binding protein (Walker, F. J. 1989. J. Biol. Chem. 264:17645-17658). A synthetic peptide, GVQLDLDEAI, corresponding to that region of protein S has been used to investigate the protein S/C4b-binding protein interaction in vitro and in vivo. Rabbit activated protein C possesses species-specific anticoagulant activity for which rabbit protein S functions as a cof...

  7. Does plasmin have anticoagulant activity?

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    Jane Hoover-Plow

    2010-03-01

    Full Text Available Jane Hoover-PlowJoseph J Jacobs Center for Thrombosis and Vascular Biology, Departments of Cardiovascular Medicine and Molecular Cardiology, Lerner Research Institute Cleveland Clinic, Ohio, USAAbstract: The coagulation and fibrinolytic pathways regulate hemostasis and thrombosis, and an imbalance in these pathways may result in pathologic hemophilia or thrombosis. The plasminogen system is the primary proteolytic pathway for fibrinolysis, but also has important proteolytic functions in cell migration, extracellular matrix degradation, metalloproteinase activation, and hormone processing. Several studies have demonstrated plasmin cleavage and inactivation of several coagulation factors, suggesting plasmin may be not only be the primary fibrinolytic enzyme, but may have anticoagulant properties as well. The objective of this review is to examine both in vitro and in vivo evidence for plasmin inactivation of coagulation, and to consider whether plasmin may act as a physiological regulator of coagulation. While several studies have demonstrated strong evidence for plasmin cleavage and inactivation of coagulation factors FV, FVIII, FIX, and FX in vitro, in vivo evidence is lacking for a physiologic role for plasmin as an anticoagulant. However, inactivation of coagulation factors by plasmin may be useful as a localized anticoagulant therapy or as a combined thrombolytic and anticoagulant therapy.Keywords: thrombosis, anticoagulant, cardiovascular disease, plasminogen’s protease, blood

  8. Monitoring Oral Anticoagulant Therapy: Measuring Coagulant Activity

    DEFF Research Database (Denmark)

    Attermann, Jorn

    Life-long oral anticoagulant therapy (OAT) with vitamin K antagonists is offered to patients with increased risk of thrombosis, e.g. patients with artificial heart valves or with atrial fibrillation. It is estimated that in 1992 in the Nordic countries 0.3 – 0.5% of the population was undergoing...... daily anticoagulant therapy. The therapy necessitates close monitoring of coagulant activity, since excess doses of anticoagulant medicine may lead to life-threatening bleedings. Traditionally, patients on OAT are required to pay regular visits to a physician, who decides on drug dosage adjustments...

  9. Heterofucans from Dictyota menstrualis have anticoagulant activity

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    I.R.L. Albuquerque

    2004-02-01

    Full Text Available Fucan is a term used to denote a family of sulfated L-fucose-rich polysaccharides which are present in the extracellular matrix of brown seaweed and in the egg jelly coat of sea urchins. Plant fucans have several biological activities, including anticoagulant and antithrombotic, related to the structural and chemical composition of polysaccharides. We have extracted sulfated polysaccharides from the brown seaweed Dictyota menstrualis by proteolytic digestion, followed by separation into 5 fractions by sequential acetone precipitation. Gel electrophoresis using 0.05 M 1,3-diaminopropane-acetate buffer, pH 9.0, stained with 0.1% toluidine blue, showed the presence of sulfated polysaccharides in all fractions. The chemical analyses demonstrated that all fractions are composed mainly of fucose, xylose, galactose, uronic acid, and sulfate. The anticoagulant activity of these heterofucans was determined by activated partial thromboplastin time (APTT using citrate normal human plasma. Only the fucans F1.0v and F1.5v showed anticoagulant activity. To prolong the coagulation time to double the baseline value in the APTT, the required concentration of fucan F1.0v (20 µg/ml was only 4.88-fold higher than that of the low molecular weight heparin Clexane® (4.1 µg/ml, whereas 80 µg/ml fucan 1.5 was needed to obtain the same effect. For both fucans this effect was abolished by desulfation. These polymers are composed of fucose, xylose, uronic acid, galactose, and sulfate at molar ratios of 1.0:0.8:0.7:0.8:0.4 and 1.0:0.3:0.4:1.5:1.3, respectively. This is the fist report indicating the presence of a heterofucan with higher anticoagulant activity from brown seaweed.

  10. Relationship between vitamin K dependent coagulation factors and anticoagulants (protein C and protein S) in neonatal vitamin K deficiency.

    OpenAIRE

    Matsuzaka, T; Tanaka, H.; Fukuda, M; Aoki, M.; Tsuji, Y; Kondoh, H

    1993-01-01

    To determine the relationship between vitamin K dependent coagulation factors and natural anticoagulants, namely protein C and protein S, in various degrees of vitamin K deficiency, plasma values for clotting activity, protein induced by vitamin K absence (PIVKA-II), protein C antigen, gamma-carboxy protein C antigen, and protein S antigen including total and free fractions and activity of protein C were measured in 66 full term and healthy breast fed neonates who did not receive vitamin K su...

  11. Anticoagulation inhibits tumor cell-mediated release of platelet angiogenic proteins and diminishes platelet angiogenic response.

    Science.gov (United States)

    Battinelli, Elisabeth M; Markens, Beth A; Kulenthirarajan, Rajesh A; Machlus, Kellie R; Flaumenhaft, Robert; Italiano, Joseph E

    2014-01-01

    Platelets are a reservoir for angiogenic proteins that are secreted in a differentially regulated process. Because of the propensity for clotting, patients with malignancy are often anticoagulated with heparin products, which paradoxically offer a survival benefit by an unknown mechanism. We hypothesized that antithrombotic agents alter the release of angiogenesis regulatory proteins from platelets. Our data revealed that platelets exposed to heparins released significantly decreased vascular endothelial growth factor (VEGF) in response to adenosine 5'-diphosphate or tumor cells (MCF-7 cells) and exhibited a decreased angiogenic potential. The releasate from these platelets contained decreased proangiogenic proteins. The novel anticoagulant fondaparinux (Xa inhibitor) demonstrated a similar impact on the platelet angiogenic potential. Because these anticoagulants decrease thrombin generation, we hypothesized that they disrupt signaling through the platelet protease-activated receptor 1 (PAR1) receptor. Addition of PAR1 antagonists to platelets decreased VEGF release and angiogenic potential. Exposure to a PAR1 agonist in the presence of anticoagulants rescued the angiogenic potential. In vivo studies demonstrated that platelets from anticoagulated patients had decreased VEGF release and angiogenic potential. Our data suggest that the mechanism by which antithrombotic agents increase survival and decrease metastasis in cancer patients is through attenuation of platelet angiogenic potential. PMID:24065244

  12. EFFECTS OF ANTICOAGULATION PROTEIN DEFECT IN MATERNAL PLASMA ON SPONTANEOUS ABORTION

    Institute of Scientific and Technical Information of China (English)

    Chun-mei Bai; Shui-qing Ma; Ming-ying Gai; Lian-kai Fan; Feng-yan Ren; Guang-sheng Fan

    2004-01-01

    Objective To investigate the mechanism of anticoagulation protein defect in the pathogenesis of unexplained recurrent miscarriage.Methods Fifty-seven patients with a history of unexplained abortion were enrolled as the investigation group for tests of protein C, protein S, antithrombin Ⅲ (AT-Ⅲ), as well as activated protein C resistance (APC-R). The control group consisted of fifty healthy women with a history of hormal pregnancy and delivery. Blood samples were obtained for measuring serum activity of protein C, protein S, AT- Ⅲ, and APC-R. Patients with positive APC-R were tested for factor Ⅴ (FV) Leiden gene mutation by PCR-RFLP method.Results Of the 57 patients, 12 (21.1%), 1 (1.8%), and 5 (8.8%) cases were found with protein S, protein C, and AT-Ⅲdeficiency respectively, and 13 (22.8%) cases with positive results of APC-R. Of the control group, no protein C or AT-Ⅲdeficiency was ever found, whereas 2 (4.0%) volunteers were presented with protein S deficiency and 3 (6.0%) with positive results of APC-R. No FV Leiden gene mutation was identified in all the patients with positive APC-R results. Late spontaneous abortion cases had higher incidence of anticoagulation protein defect than the early cases.Conclusion Anticoagulation protein defect may play a role in the pathogenesis of fetal loss, especially for those occurring in late stage of pregnancy.

  13. Chemically sulfated natural galactomannans with specific antiviral and anticoagulant activities.

    Science.gov (United States)

    Muschin, Tegshi; Budragchaa, Davaanyam; Kanamoto, Taisei; Nakashima, Hideki; Ichiyama, Koji; Yamamoto, Naoki; Shuqin, Han; Yoshida, Takashi

    2016-08-01

    Naturally occurring galactomannans were sulfated to give sulfated galactomannans with degrees of substitution of 0.7-1.4 per sugar unit and molecular weights of M¯n=0.6×10(4)-2.4×10(4). Sulfated galactomannans were found to have specific biological activities in vitro such as anticoagulant, anti-HIV and anti-Dengue virus activities. The biological activities were compared with those of standard dextran and curdlan sulfates, which are polysaccharides with potent antiviral activity and low cytotoxicity. It was found that sulfated galactomannans had moderate to high anticoagulant activity, 13.4-36.6unit/mg, compared to that of dextran and curdlan sulfates, 22.7 and 10.0unit/mg, and high anti-HIV and anti-Dengue virus activities, 0.04-0.8μg/mL and 0.2-1.1μg/mL, compared to those curdlan sulfates, 0.1μg/mL, respectively. The cytotoxicity on MT-4 and LCC-MK2 cells was low. Surface plasmon resonance (SPR) of sulfated galactomannans revealed strong interaction with poly-l-lysine as a model compound of virus proteins, and suggested that the specific biological activities might originate in the electrostatic interaction of negatively charged sulfate groups of sulfated galactomannans and positively charged amino groups of surface proteins of viruses. These results suggest that sulfated galactomannans effectively prevented the infection of cells by viruses and the degree of substitution and molecular weights played important roles in the biological activities. PMID:27154517

  14. Interaction of Heparin with Two Synthetic Peptides That Neutralize the Anticoagulant Activity of Heparin+

    OpenAIRE

    Jing WANG; Rabenstein, Dallas L.

    2006-01-01

    Two synthetic analogs of the heparin-binding domain of heparin/heparan sulfate-interacting protein: Ac-SRGKAKVKAKVKDQTK-NH2 and the all-D-amino acid version of the same peptide (L-HIPAP and D-HIPAP, respectively) were synthesized and their efficacy as agents for neutralization of the anticoagulant activity of heparin was assayed. The two analog peptides were found to be equally effective for neutralization of the anticoagulant activity of heparin, as measured by restoration of the activity of...

  15. Complement inhibitory and anticoagulant activities of fractionated heparins

    NARCIS (Netherlands)

    Hennink, W.E.; Klerx, J.P.A.M.; Dijk, H. van; Feijen, J.

    1984-01-01

    Almost monodisperse heparin fractions (w/n < 1.1) were obtained by gel filtration of a commercial heparin. These fractions were assayed for anticoagulant activity (thrombin times and APTT), chromogenic anti-factor Xa activity, inhibitory activity for the human classical complement pathway, carboxyl

  16. Anticoagulation activity of salivary gland extract of oriental blackfly Simulium indicum

    Institute of Scientific and Technical Information of China (English)

    Subhalaxmi Borah; Ashok Naglot; Sewali Goswami; Imtiaz Rahman; Manab Deka

    2014-01-01

    Objective: To study the morphology of the salivary gland of the female blackfly of the speciesSimulium indicum gland extract.Methods:(S. indicum) along with protein profile and anticoagulant activity of the salivary protein profile of the salivary gland extract (SGE) and anticoagulant activities against thrombin, and the extrinsic and intrinsic coagulation pathways were found in S. indicum SGE in the TT, PT and APTT assays, respectively.Results:Sodium dodecyl sulphate polyacrylamide gel electrophoresis was used to analyze the and a more or less spherical reservoir. The protein contents of whole salivary glands were also quantified and the amount of salivary gland proteins in the adult female S. indicum was found out to be approximately 1.12±0.13 µg/female. At least 16 major and several minor protein bands Results revealed that each gland consisted of a cylindrical U-shaped secretory lobe were detected in the female salivary glands. The molecular masses of these major protein bands were estimated at 69, 65, 61, 58, 44, 42, 39, 33, 30, 28, 27, 26, 23, 21, 18 and 16 kDa, consecutively. Anticoagulant activities were found in S. indicum SGE in all the assays. It was found that SGE prolonged human plasma clotting time in a dose-dependent manner. Factor Xa inhibition was shown by the SGE of S. indicum. Percent inhibition value was 93.8. A positive correlation (r=0.89) was observed between total protein and percent inhibition of factor Xa. Conclusions: The present study demonstrated that the mode of action of the anticoagulant(s) is mainly on the inhibition of thrombin and factor Xa along with other target factors of the coagulation cascade.

  17. Coagulant and anticoagulant activities in Jatropha curcas latex.

    Science.gov (United States)

    Osoniyi, Omolaja; Onajobi, Funmi

    2003-11-01

    Jatropha curcas Linn. (Euphorbiaceae), a medicinal plant commonly grown in the Tropics, is traditionally used as a haemostatic. Investigation of the coagulant activity of the latex of Jatropha curcas showed that whole latex significantly (Platex, however, prolonged the clotting time: at high dilutions, the blood did not clot at all. This indicates that Jatropha curcas latex possesses both procoagulant and anticoagulant activities. Prothrombin time (PT) and activated partial thromboplastin time (APTT) tests on plasma confirm these observations. Solvent partitioning of the latex with ethyl acetate and butanol led to a partial separation of the two opposing activities: at low concentrations, the ethyl acetate fraction exhibited a procoagulant activity, while the butanol fraction had the highest anticoagulant activity. The residual aqueous fraction had no significant effect on the clotting time of blood and the PT but slightly prolonged the APTT.

  18. Deficiency of the natural anticoagulant proteins in women with pregnancy related venous thromboembolism

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    Mitić Gorana

    2009-01-01

    Full Text Available Inherited thrombophilia can be defined as a predisposition to thrombosis caused by heritable defects, such as mutations in genes encoding the natural anticoagulants or clotting factors. Pregnancy related risk of VTE is sixfold increased comparing to non pregnant age matched women. Pregnancy is an independent risk factor for the development of venous thromboembolism and this risk is further increased by the presence of thrombophilia. Aim of the study: The aim of the study was to evaluate the association between deficiency of natural anticoagulants: antithrombin, protein C and protein S and pregnancy related thromboembolism. We have determined the activities of antithrombin, proten C and protein S in 74 women with pregnancy related thrombosis and in 45 healthy women who had at least two uncomplicated pregnancies. Among the women with the history of venous thromboembolism antithrombin deficiency was found in 4 (5.4%, protein C deficiency in 2 (2.7% and protein S deficiency in 5 (6.76%. The total of 11 (14.6% women was found to be deficient. Not a single woman in the control group was found to be deficient in natural anticoagulants. Deficiencies of coagulation inhibitors are associated with an increased risk of venous thrombosis during pregnancy and puerperium (p= 0.006. Antithrombin, protein C and protein S deficient women are at higher risk of developing venous thromboembolism during antepartal period (p= 0.0097. Prophylactic treatment with heparin should be recommended from the very beginning of the following pregnancy in women with antithrombin, protein C or protein S deficiency.

  19. Improvements of anticoagulant activities of silk fibroin films with fucoidan

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Fucoidan (FC),an effective anticoagulant constituent extracted from brown algae,was introduced into silk fibroin (SF) for improving its blood compatibility.The SF and SF/FC blend films were characterized by attenuated total reflectance Fourier-transform infrared (ATR-FTIR),X-ray photoelectron spectroscopy (XPS),scanning electron microscopy (SEM) and dynamic contact angle determinator (CA).The in vitro anticoagulant activities of the films were evaluated by activated partial thromboplastin time (APTT),thrombin time (TT) and prothrombin time (PT) measurements.The endothelial cell attachment and proliferation viability on the film were assessed by micropipette aspiration technique and MTT assay,respectively.The testing results indicated that the introduction of FC increased the roughness,hydrophilicity and sulfate component of the film surface without impeding the formation of β-sheet conformation in SF.More important,FC brought excellent anticoagulant activity and better endothelial cell affinity to SF.The SF/FC blend film was hopeful to be used as blood-contacting biomaterials.

  20. In-vitro anticoagulant activity of fucoidan derivatives from brown seaweed Laminaria japonica

    Institute of Scientific and Technical Information of China (English)

    WANG Jing; ZHANG Quanbin; ZHANG Zhongshan; HOU Yun; ZHANG Hong

    2011-01-01

    Fucoidan, a group of sulfated heteropolysaccharides, was extracted from Laminariajaponica,an important economic alga species in China. The anticoagulant activity of fucoidan and its derivatives (including sulfated, phosphorylated, and aminated fucoidan) was examined using in-vitro anticoagulant systems. The correlation between chemical variations within the fucoidan group and anticoagulant activity was determined. The in-vitro anticoagulant properties of fucoidan and its derivatives were determined by measuring activated partial thromboplastin time (APTT), prothrombin time (PT), and thrombin time (TT).The results indicate anticoagulant activity in all samples using APTT and TT assays; however, only the fucoidan derivatives affected the PT assay. Thus, the fucoidan derivatives were able to inhibit both intrinsic and extrinsic blood coagulants. Fucoidan (FPS) and its derivatives presented better anticoagulant activity than low molecular weight fucoidan (DFPS) and its derivatives, suggesting that molecular weight and proper conformation are contributing factors for anticoagulant activity of polysaccharides. Amino groups have a positive charge and can thus change the charge density of fucoidan. Accordingly, among the tested samples, aminated fucoidan (NF) was the most active reflecting the importance of charge density for anticoagulant activity. Available data obtained using in-vitro models suggest that the sulfate content,sulfate/total-sugar ratio, molecular weight, and the substituted group of fucoidan are important factors for anticoagulant activity but that the influence of sulfate, phosphate and amino groups on anticoagulant activity was different.

  1. In-vitro anticoagulant activity of fucoidan derivatives from brown seaweed Laminaria japonica

    Science.gov (United States)

    Wang, Jing; Zhang, Quanbin; Zhang, Zhongshan; Hou, Yun; Zhang, Hong

    2011-05-01

    Fucoidan, a group of sulfated heteropolysaccharides, was extracted from Laminaria japonica, an important economic alga species in China. The anticoagulant activity of fucoidan and its derivatives (including sulfated, phosphorylated, and aminated fucoidan) was examined using in-vitro anticoagulant systems. The correlation between chemical variations within the fucoidan group and anticoagulant activity was determined. The in-vitro anticoagulant properties of fucoidan and its derivatives were determined by measuring activated partial thromboplastin time (APTT), prothrombin time (PT), and thrombin time (TT). The results indicate anticoagulant activity in all samples using APTT and TT assays; however, only the fucoidan derivatives affected the PT assay. Thus, the fucoidan derivatives were able to inhibit both intrinsic and extrinsic blood coagulants. Fucoidan (FPS) and its derivatives presented better anticoagulant activity than low molecular weight fucoidan (DFPS) and its derivatives, suggesting that molecular weight and proper conformation are contributing factors for anticoagulant activity of polysaccharides. Amino groups have a positive charge and can thus change the charge density of fucoidan. Accordingly, among the tested samples, aminated fucoidan (NF) was the most active reflecting the importance of charge density for anticoagulant activity. Available data obtained using in-vitro models suggest that the sulfate content, sulfate/total-sugar ratio, molecular weight, and the substituted group of fucoidan are important factors for anticoagulant activity but that the influence of sulfate, phosphate and amino groups on anticoagulant activity was different.

  2. Anticoagulant response to Agkistrodon contortrix venom (ACV test): a new global test to screen for defects in the anticoagulant protein C pathway.

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    Robert, A; Eschwège, V; Hameg, H; Drouet, L; Aillaud, M F

    1996-04-01

    As specific assays used to identify defects in the protein C (PC) anticoagulant pathway are laborious and expensive, we describe here a global test to screen for these defects. This assay is expressed as the ratio of two activated partial thromboplastin times, one in the absence and one in the presence of 0,125 U/ml of the PC activator of Agkistrodon contortrix venom (ACV). Eight of the 168 healthy volunteers of the control group exhibited an ACV ratio below the lower normal limit of 3.37 [6 subjects with the mutation Arg 506 to Gln in their factor V gene (FV R506Q) and one with PS deficiency]. 128 patients who have had at least one episode of deep-vein thrombosis were retrospectively studied. All patients carrying FV Q506R (n = 48), PC deficiency (n = 14) or combined defects, i.e. FV Q506R and PC deficiency (n = 4) or FV Q506R and PS deficiency (n = 3), had ACV ratios ACV ratios which overlapped normal range. ACV ratios of one out of seven patients with antithrombin deficiency, and 10% of patients without identified defect in the PC anticoagulant pathway (n = 30) were ACV ratio raised to 3.70 could lead to a test identifying all patients with a defect in the PC anticoagulant pathway.

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

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    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.

  4. Protein source and choice of anticoagulant decisively affect nanoparticle protein corona and cellular uptake

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    Schöttler, S.; Klein, Katja; Landfester, K.; Mailänder, V.

    2016-03-01

    Protein adsorption on nanoparticles has been a focus of the field of nanocarrier research in the past few years and more and more papers are dealing with increasingly detailed lists of proteins adsorbed to a plethora of nanocarriers. While there is an urgent need to understand the influence of this protein corona on nanocarriers' interactions with cells the strong impact of the protein source on corona formation and the consequence for interaction with different cell types are factors that are regularly neglected, but should be taken into account for a meaningful analysis. In this study, the importance of the choice of protein source used for in vitro protein corona analysis is concisely investigated. Major and decisive differences in cellular uptake of a polystyrene nanoparticle incubated in fetal bovine serum, human serum, human citrate and heparin plasma are reported. Furthermore, the protein compositions are determined for coronas formed in the respective incubation media. A strong influence of heparin, which is used as an anticoagulant for plasma generation, on cell interaction is demonstrated. While heparin enhances the uptake into macrophages, it prevents internalization into HeLa cells. Taken together we can give the recommendation that human plasma anticoagulated with citrate seems to give the most relevant results for in vitro studies of nanoparticle uptake.Protein adsorption on nanoparticles has been a focus of the field of nanocarrier research in the past few years and more and more papers are dealing with increasingly detailed lists of proteins adsorbed to a plethora of nanocarriers. While there is an urgent need to understand the influence of this protein corona on nanocarriers' interactions with cells the strong impact of the protein source on corona formation and the consequence for interaction with different cell types are factors that are regularly neglected, but should be taken into account for a meaningful analysis. In this study, the importance

  5. Protein source and choice of anticoagulant decisively affect nanoparticle protein corona and cellular uptake.

    Science.gov (United States)

    Schöttler, S; Klein, Katja; Landfester, K; Mailänder, V

    2016-03-14

    Protein adsorption on nanoparticles has been a focus of the field of nanocarrier research in the past few years and more and more papers are dealing with increasingly detailed lists of proteins adsorbed to a plethora of nanocarriers. While there is an urgent need to understand the influence of this protein corona on nanocarriers' interactions with cells the strong impact of the protein source on corona formation and the consequence for interaction with different cell types are factors that are regularly neglected, but should be taken into account for a meaningful analysis. In this study, the importance of the choice of protein source used for in vitro protein corona analysis is concisely investigated. Major and decisive differences in cellular uptake of a polystyrene nanoparticle incubated in fetal bovine serum, human serum, human citrate and heparin plasma are reported. Furthermore, the protein compositions are determined for coronas formed in the respective incubation media. A strong influence of heparin, which is used as an anticoagulant for plasma generation, on cell interaction is demonstrated. While heparin enhances the uptake into macrophages, it prevents internalization into HeLa cells. Taken together we can give the recommendation that human plasma anticoagulated with citrate seems to give the most relevant results for in vitro studies of nanoparticle uptake. PMID:26804616

  6. Anticoagulant activities of piperlonguminine in vitro and in vivo

    Directory of Open Access Journals (Sweden)

    Wonhwa Lee

    2013-10-01

    Full Text Available Piperlonguminine (PL, an important component of Piperlongum fruits, is known to exhibit anti-hyperlipidemic, antiplateletand anti-melanogenic activities. Here, the anticoagulantactivities of PL were examined by monitoring activatedpartial-thromboplastin-time (aPTT, prothrombin-time (PT, andthe activities of thrombin and activated factor X (FXa. Theeffects of PL on the expressions of plasminogen activatorinhibitor type 1 (PAI-1 and tissue-type plasminogen activator(t-PA were also tested in tumor necrosis factor-α (TNF-αactivated HUVECs. The results showed that PL prolonged aPTTand PT significantly and inhibited the activities of thrombin andFXa. PL inhibited the generation of thrombin and FXa inHUVECs. In accordance with these anticoagulant activities, PLprolonged in vivo bleeding time and inhibited TNF-α inducedPAI-1 production. Furthermore, PAI-1/t-PA ratio was significantlydecreased by PL. Collectively, our results suggest that PLpossesses antithrombotic activities and that the current studycould provide bases for the development of new anticoagulantagents. [BMB Reports 2013; 46(10: 484-489

  7. Anticoagulant rodenticides.

    Science.gov (United States)

    Watt, Barbara E; Proudfoot, Alex T; Bradberry, Sally M; Vale, J Allister

    2005-01-01

    Anticoagulant pesticides are used widely in agricultural and urban rodent control. The emergence of warfarin-resistant strains of rats led to the introduction of a new group of anticoagulant rodenticides variously referred to as 'superwarfarins', 'single dose' or 'long-acting'. This group includes the second generation 4-hydroxycoumarins brodifacoum, bromadiolone, difenacoum, flocoumafen and the indanedione derivatives chlorophacinone and diphacinone. Most cases of anticoagulant rodenticide exposure involve young children and, as a consequence, the amounts ingested are almost invariably small. In contrast, intentional ingestion of large quantities of long-acting anticoagulant rodenticides may cause anticoagulation for several weeks or months. Occupational exposure has also been reported. Anticoagulant rodenticides inhibit vitamin K(1)-2,3 epoxide reductase and thus the synthesis of vitamin K and subsequently clotting factors II, VII, IX and X. The greater potency and duration of action of long-acting anticoagulant rodenticides is attributed to their: (i) greater affinity for vitamin K(1)-2,3-epoxide reductase; (ii) ability to disrupt the vitamin K(1)-epoxide cycle at more than one point; (iii) hepatic accumulation; and (iv) unusually long biological half-lives due to high lipid solubility and enterohepatic circulation. Substantial ingestion produces epistaxis, gingival bleeding, widespread bruising, haematomas, haematuria with flank pain, menorrhagia, gastrointestinal bleeding, rectal bleeding and haemorrhage into any internal organ; anaemia may result. Spontaneous haemoperitoneum has been described. Severe blood loss may result in hypovolaemic shock, coma and death. The first clinical signs of bleeding may be delayed and patients may remain anticoagulated for several days (warfarin) or days, weeks or months (long-acting anticoagulants) after ingestion of large amounts. There are now sufficient data in young children exposed to anticoagulant rodenticides to

  8. Anticoagulant Activity of Polyphenolic-Polysaccharides Isolated from Melastoma malabathricum L.

    Directory of Open Access Journals (Sweden)

    Li Teng Khoo

    2014-01-01

    Full Text Available Melastoma malabathricum Linn. is a perennial traditional medicine plants that grows abundantly throughout Asian countries. In this study, M. malabathricum Linn. leaf hot water crude extract with anticoagulant activity was purified through solid phase extraction cartridge and examined for the bioactive chemical constituents on blood coagulation reaction. The SPE purified fractions were, respectively, designated as F1, F2, F3, and F4, and each was subjected to the activated partial thromboplastin time (APTT anticoagulant assay. Active anticoagulant fractions (F1, F2, and F3 were subjected to chemical characterisation evaluation. Besides, neutral sugar for carbohydrate part was also examined. F1, F2, and F3 were found to significantly prolong the anticoagulant activities in the following order, F1>F2>F3, in a dose dependent manner. In addition, carbohydrate, hexuronic acid, and polyphenolic moiety were measured for the active anticoagulant fractions (F1, F2, and F3. The characterisation of chemical constituents revealed that all these three fractions contained acidic polysaccharides (rhamnogalacturonan, homogalacturonan, and rhamnose hexose-pectic type polysaccharide and polyphenolics. Hence, it was concluded that the presence of high hexuronic acids and polysaccharides, as well as polyphenolics in traditional medicinal plant, M. malabathricum, played a role in prolonging blood clotting in the intrinsic pathway.

  9. Antimicrobial and anticoagulant activities of the spine of stingray Himantura imbricata

    Institute of Scientific and Technical Information of China (English)

    Kaliyamoorthy Kalidasan; Velayudham Ravi; Sunil Kumar Sahu; Murugan Lakshmi Maheshwaran; Kathiresan Kandasamy

    2014-01-01

    Objective:To study the spine structure of stingray Himantura imbricata (H. imbricata) and to evaluate the anticoagulant properties of the spine extract obtained through various solvents extracts followed by antibacterial activity against human pathogens. Methods:Spines of H. imbricata were collected from Nagappattinam coast, Tamil Nadu, India and their spines were observed under the light microscope. The grounded spines were subjected to extraction of metabolites using methanol, ethanol, chloroform and acetone. Antibacterial activity was evaluated by disc diffusion technique against 10 human pathogens. Similarly, anticoagulant activity was also assessed by following United States Pharmacopeia method. Results:Light microscopic observation of spine revealed that the venom apparatus of the stingray H. imbricata consisted of two to three spines, glandular tissue and a sheath. The spine extract showed potent antibacterial activity against all tested pathogen. Maximum activity (14 mm) was found against Staphylococcus aureus. Crude extract showed 91.50 USP units/mg of anticoagulant activity. Conclusions: Microscopic observations gave new insight about the spine structure of the stingray. The spine extracts of H. imbricate showed potent activity against human pathogens revealed by the good zone of inhibition. Chloroform extracts conferred the most prominent antibacterial activity. The anticoagulant activity was also comparable with that of standard heparin.

  10. Antimicrobial and anticoagulant activities of the spine of stingray Himantura imbricata

    Directory of Open Access Journals (Sweden)

    Kaliyamoorthy Kalidasan

    2014-02-01

    Full Text Available Objective: To study the spine structure of stingray Himantura imbricata (H. imbricata and to evaluate the anticoagulant properties of the spine extract obtained through various solvents extracts followed by antibacterial activity against human pathogens. Methods: Spines of H. imbricata were collected from Nagappattinam coast, Tamil Nadu, India and their spines were observed under the light microscope. The grounded spines were subjected to extraction of metabolites using methanol, ethanol, chloroform and acetone. Antibacterial activity was evaluated by disc diffusion technique against 10 human pathogens. Similarly, anticoagulant activity was also assessed by following United States Pharmacopeia method. Results: Light microscopic observation of spine revealed that the venom apparatus of the stingray H. imbricata consisted of two to three spines, glandular tissue and a sheath. The spine extract showed potent antibacterial activity against all tested pathogen. Maximum activity (14 mm was found against Staphylococcus aureus. Crude extract showed 91.50 USP units/mg of anticoagulant activity. Conclusions: Microscopic observations gave new insight about the spine structure of the stingray. The spine extracts of H. imbricate showed potent activity against human pathogens revealed by the good zone of inhibition. Chloroform extracts conferred the most prominent antibacterial activity. The anticoagulant activity was also comparable with that of standard heparin.

  11. Biological Variations of Lupus Anticoagulant, Antithrombin, Protein C, Protein S, and von Willebrand Factor Assays.

    Science.gov (United States)

    Shou, Weiling; Chen, Qian; Wu, Wei; Cui, Wei

    2016-02-01

    The results of lupus anticoagulant (LA), antithrombin (AT), protein C (PC), and protein S (PS) testing, and the values of von Willebrand factor antigen (VWF:Ag) are important in diagnosis and therapeutic monitoring of thrombosis and hemostasis diseases. Till now, no published study has focused on the biological variations in LA testing, and only a few studies have examined the biological variations of AT, PC, PS, and VWF:Ag. With the latest fully automated instruments and improved reagents, the analytical, within-subject, and between-subject biological variations were estimated for these five coagulant parameters in a cohort of 25 apparently healthy subjects. Blood specimens were collected at 8:00 am, 12:00 pm, and 4:00 pm on days 1, 3, and 5. The analytical biological variation (CV(A)) values of all the parameters were less than 3%. The within-subject biological variation (CV(W)) and between-subject biological variation (CV(G)) values of the LA normalized ratio were 4.64 and 6.83%, respectively. No significant differences were observed in the intraday and interday biological variations of LA tests, or in AT, PC, PS, and VWF:Ag values. Additionally, the utility of the conventional population-based reference intervals of the five coagulation parameters was evaluated by the index of individuality, and data on CV(W) and CV(A) were used to calculate the reference change value to identify the significance of changes in serial results from the same individual. PMID:26516946

  12. A comparison of seven methods to analyze heparin in biomaterials: quantification, location, and anticoagulant activity

    NARCIS (Netherlands)

    Lammers, G.; Westerlo, E.M.A. van de; Versteeg, E.M.M.; Kuppevelt, A.H.M.S.M. van; Daamen, W.F.

    2011-01-01

    Glycosaminoglycans, like heparin, are frequently incorporated in biomaterials because of their capacity to bind and store growth factors and because of their hydrating properties. Heparin is also often used in biomaterials for its anticoagulant activity. Analysis of biomaterial-bound heparin is chal

  13. Antioxidant and anticoagulant activity of sulfated polysaccharide from Gracilaria debilis (Forsskal).

    Science.gov (United States)

    Sudharsan, Sadhasivam; Subhapradha, Namasivayam; Seedevi, Palaniappan; Shanmugam, Vairamani; Madeswaran, Perumal; Shanmugam, Annaian; Srinivasan, Alagiri

    2015-11-01

    Sulfated polysaccharide was isolated from Gracilaria debilis and purified through gel chromatography and their molecular weight was determined through AGE and PAGE. The total sugars in the crude, fractionated and purified polysaccharide were estimated as 52.65%, 59.70% and 67.60%, respectively. The ash and moisture content of crude and purified polysaccharide was found to be 14.2% and 23.5% and the polysaccharide was free from protein contamination. The sulfate and uronic acid contents in the crude, fractionated and purified were estimated as 14.08%, 15.33% and 16.01% and 10.12%, 13.56%, 16.70%. The elemental composition including carbon (crude - 23.12%, purified - 21.05%), hydrogen (crude - 3.4%, purified - 4.13%) and nitrogen (crude - 1.22%, purified - 0.56%) were also analyzed. The anticoagulant activity of the sulfated polysaccharide through APTT and PT was estimated at 14.11 and 8.23IU/mg. The purified polysaccharide with the molecular mass of 20kDa showed highest antioxidant activity (38.57%, 43.48% and 38.88%) in all the assays tested such as DPPH hydroxyl radical, superoxide radical, hydroxyl radical scavenging activities and the structural property was analyzed through FT-IR and (1)H NMR spectrum. The results together suggest that the isolated low molecular weight sulfated polysaccharide will demonstrate as a enormously available alternative natural source of antioxidant for industrial uses.

  14. Antioxidant and anticoagulant activity of sulfated polysaccharide from Gracilaria debilis (Forsskal).

    Science.gov (United States)

    Sudharsan, Sadhasivam; Subhapradha, Namasivayam; Seedevi, Palaniappan; Shanmugam, Vairamani; Madeswaran, Perumal; Shanmugam, Annaian; Srinivasan, Alagiri

    2015-11-01

    Sulfated polysaccharide was isolated from Gracilaria debilis and purified through gel chromatography and their molecular weight was determined through AGE and PAGE. The total sugars in the crude, fractionated and purified polysaccharide were estimated as 52.65%, 59.70% and 67.60%, respectively. The ash and moisture content of crude and purified polysaccharide was found to be 14.2% and 23.5% and the polysaccharide was free from protein contamination. The sulfate and uronic acid contents in the crude, fractionated and purified were estimated as 14.08%, 15.33% and 16.01% and 10.12%, 13.56%, 16.70%. The elemental composition including carbon (crude - 23.12%, purified - 21.05%), hydrogen (crude - 3.4%, purified - 4.13%) and nitrogen (crude - 1.22%, purified - 0.56%) were also analyzed. The anticoagulant activity of the sulfated polysaccharide through APTT and PT was estimated at 14.11 and 8.23IU/mg. The purified polysaccharide with the molecular mass of 20kDa showed highest antioxidant activity (38.57%, 43.48% and 38.88%) in all the assays tested such as DPPH hydroxyl radical, superoxide radical, hydroxyl radical scavenging activities and the structural property was analyzed through FT-IR and (1)H NMR spectrum. The results together suggest that the isolated low molecular weight sulfated polysaccharide will demonstrate as a enormously available alternative natural source of antioxidant for industrial uses. PMID:26424206

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

    OpenAIRE

    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 a flexible single-strand linker, have been shown to possess anticoagulant activity. Here, we link multiple aptamers at programmed positions on DNA nanostructures to optimize spacing and orientation o...

  16. Histones Differentially Modulate the Anticoagulant and Profibrinolytic Activities of Heparin, Heparin Derivatives, and Dabigatran.

    Science.gov (United States)

    Ammollo, Concetta Tiziana; Semeraro, Nicola; Carratù, Maria Rosaria; Colucci, Mario; Semeraro, Fabrizio

    2016-02-01

    The antithrombin activity of unfractionated heparin (UFH) is offset by extracellular histones, which, along with DNA, represent a novel mediator of thrombosis and a structural component of thrombi. Here, we systematically evaluated the effect of histones, DNA, and histone-DNA complexes on the anticoagulant and profibrinolytic activities of UFH, its derivatives enoxaparin and fondaparinux, and the direct thrombin inhibitor dabigatran. Thrombin generation was assessed by calibrated automated thrombinography, inhibition of factor Xa and thrombin by synthetic substrates, tissue plasminogen activator-mediated clot lysis by turbidimetry, and thrombin-activatable fibrinolysis inhibitor (TAFI) activation by a functional assay. Histones alone delayed coagulation and slightly stimulated fibrinolysis. The anticoagulant activity of UFH and enoxaparin was markedly inhibited by histones, whereas that of fondaparinux was enhanced. Histones neutralized both the anti-Xa and anti-IIa activities of UFH and preferentially blocked the anti-IIa activity of enoxaparin. The anti-Xa activity of fondaparinux was not influenced by histones when analyzed by chromogenic substrates, but was potentiated in a plasma prothrombinase assay. Histones inhibited the profibrinolytic activity of UFH and enoxaparin and enhanced that of fondaparinux by acting on the modulation of TAFI activation by anticoagulants. Histone H1 was mainly responsible for these effects. Histone-DNA complexes, as well as intact neutrophil extracellular traps, impaired the activities of UFH, enoxaparin, and fondaparinux. Dabigatran was not noticeably affected by histones and/or DNA, whatever the assay performed. In conclusion, histones and DNA present in the forming clot may variably influence the antithrombotic activities of anticoagulants, suggesting a potential therapeutic advantage of dabigatran and fondaparinux over heparins.

  17. Sulfated polysaccharides with antioxidant and anticoagulant activity from the sea cucumber Holothuria fuscogliva

    Science.gov (United States)

    Li, Rongfeng; Yu, Huahua; Yue, Yang; Liu, Song; Xing, Rong'e.; Chen, Xiaolin; Li, Pengcheng

    2016-08-01

    Sea cucumber is a traditional nutritional food and medicinal resource with many bioactive components in China. Holothuria fuscogliva is a big sea cucumber with a rich of bioactive polysaccharides. To investigate the bioactivities of the polysaccharides from sea cucumber H. fuscogliva, we prepared the sulfated polysaccharides (HfP) from sea cucumber H. fuscogliva using a protease hydrolysis method. Antioxidant activities of HfP were investigated, including hydroxyl radical scavenging activity and superoxide radical scavenging activity. And, the anticoagulant activities of HfP were studied, including the activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time (TT). The average molecular weight was 1 867.1 Da, with a sulfate content of 20.7%. In addition, the molar ratio of monosaccharide composition of HfP was Man: Rha: Glc A: Glc: Gal: Xyl: Fuc=0.083 6: 0.437: 0.134: 0: 1.182: 0.748: 1. It had a strong antioxidant activity, the hydroxyl and superoxide radical scavenging activity EC 50 of HfP was 3.74 and 0.037 mg/mL, respectively. It also showed a good anticoagulant activity in our study. The APTT of HfP was much higher than that of heparin sodium, and the PT and TT of HfP was close to that of heparin sodium at a low concentration. Therefore, HfP shows a good antioxidant and anticoagulant activity and it may become a potential candidate of the natural antioxidant and anticoagulant and will have a good application future in health product or medicine industry.

  18. Coagulant and anticoagulant activities of Bothrops lanceolatus (Fer de lance) venom.

    Science.gov (United States)

    Lôbo de Araújo, A; Kamiguti, A; Bon, C

    2001-01-01

    Bothrops lanceolatus venom contains caseinolytic, phospholipase, esterase and haemorrhagic activities. We have investigated the coagulant and anticoagulant actions of B. lanceolatus venom on human citrated plasma and on purified plasma components. Although B. lanceolatus venom up to 50 microg/ml was unable to clot citrated plasma, at concentrations > or = 5 microg/ml the venom dose-dependently clotted purified human fibrinogen, indicating the presence of a thrombin-like enzyme. Human plasma (final concentration > or = 12.5%) dose-dependently inhibited the venom-induced fibrinogen clotting. This finding suggested that endogenous plasma protease inhibitors can affect the venom's action on fibrinogen. To investigate this possibility, B. lanceolatus venom was incubated with different plasma protease inhibitors and the activity on fibrinogen tested. alpha(2)-Macroglobulin and alpha(1)-antitrypsin did not interfere with the coagulant activity of the venom whereas the antithrombin-III/heparin complex partially inhibited this activity. A non-toxic, acidic phospholipase A(2) purified from B. lanceolatus venom prolonged the activated partial thromboplastin time in human plasma from 39.7+/-0.5 s (control with saline) to 60.2+/-0.9 s with 50 microg of PLA(2) (p<0.001), suggesting an anticoagulant activity associated with this enzyme. This anticoagulant activity may account for some of the effects of the venom on blood coagulation. PMID:10978756

  19. An Antithrombin-Heparin Complex Increases the Anticoagulant Activity of Fibrin Clots

    Directory of Open Access Journals (Sweden)

    Lesley J. Smith

    2008-01-01

    Full Text Available Clotting blood contains fibrin-bound thrombin, which is a major source of procoagulant activity leading to clot extension and further activation of coagulation. When bound to fibrin, thrombin is protected from inhibition by antithrombin (AT + heparin but is neutralized when AT and heparin are covalently linked (ATH. Here, we report the surprising observation that, rather than yielding an inert complex, thrombin-ATH formation converts clots into anticoagulant surfaces that effectively catalyze inhibition of thrombin in the surrounding environment.

  20. Depolymerized glycosaminoglycan and its anticoagulant activities from sea cucumber Apostichopus japonicus.

    Science.gov (United States)

    Yang, Jie; Wang, Yuanhong; Jiang, Tingfu; Lv, Lv; Zhang, Boyuan; Lv, Zhihua

    2015-01-01

    A controlled Cu(2+) catalytic free-radical depolymerization process of fucosylated chondroitin sulfate from sea cucumber Apostichopus japonicus was established. The results showed a good linear relationship between 1/Mw and time during the depolymerization. A series of fractions with different molecular weight were obtained, and the physicochemical properties of them were investigated and compared utilizing the chemical method, IR spectra and NMR spectra. The results showed no significant variations of the backbone and branches structures during the depolymerization. Furthermore, the anticoagulant activities of the depolymerized fractions were evaluated by the activated partial thromboplastin time (APTT). The APTT decreases in proportion to the molecular weight following a linear relationship and the prolongation of APTT activity requires at least oligosaccharide of 4 trisaccharide units (about 4000 Da). Their anticoagulant activity of low molecular weight fraction (Mw = 24,755 Da) is similar to LMWH with significantly less bleeding risk. The results suggest that the low molecular weight fraction could be used as a novel anticoagulant with less undesired side effects. PMID:25260572

  1. Molecular design, synthesis and anticoagulant activity evaluation of fluorinated dabigatran analogues.

    Science.gov (United States)

    Wang, Fei; Ren, Yu-Jie; Dong, Ming-Hui

    2016-06-15

    In the present study, a series of unreported fluorinated dabigatran analogues, which were based on the structural scaffold of dabigatran, were designed by computer-aided simulation. Fifteen fluorinated dabigatran analogues were screened and synthesized. All target compounds were characterized by (1)H NMR, (13)C NMR, (19)F NMR and HRMS. According to the preliminary screening results of inhibition ratio, eleven analogues (inhibition ratio >90%) were evaluated for antithrombin activity in vitro (IC50). The test results expressed that all the analogues showed effective inhibitory activities against thrombin. Especially, compounds 8f, 8k and 8o, with IC50 values of 1.81, 3.21 and 2.16nM, respectively, showed remarkable anticoagulant activities which were in the range of reference drug dabigatran (IC50=1.23nM). Moreover, compounds 8k and 8o were developed to investigate their anticoagulant activities in vivo. In those part, compound 8o exhibited a fairly strong inhibitory action for arteriovenous thrombosis with inhibition ratio of 84.66%, which was comparable with that of dabigatran (85.07%). Docking simulations demonstrated that these compounds could act as candidates for further development of novel anticoagulant drugs.

  2. Sulfonation and anticoagulant activity of fungal exocellular β-(1→6)-D-glucan (lasiodiplodan).

    Science.gov (United States)

    Vasconcelos, Ana Flora D; Dekker, Robert F H; Barbosa, Aneli M; Carbonero, Elaine R; Silveira, Joana L M; Glauser, Bianca; Pereira, Mariana Sá; Corradi da Silva, Maria de Lourdes

    2013-02-15

    An exocellular β-(1→6)-D-glucan (lasiodiplodan) produced by a strain of Lasiodiplodia theobromae (MMLR) grown on sucrose was derivatized by sulfonation to promote anticoagulant activity. The structural features of the sulfonated β-(1→6)-D-glucan were investigated by UV-vis, FT-IR and (13)C NMR spectroscopy, and the anticoagulant activity was investigated by the classical coagulation assays APTT, PT and TT using heparin as standard. The content of sulfur and degree of substitution of the sulfonated glucan was 11.73% and 0.95, respectively. UV spectroscopy showed a band at 261 nm due to the unsaturated bond formed in the sulfonation reaction. Results of FT-IR and (13)C NMR indicated that sulfonyl groups were inserted on the polysaccharide. The sulfonated β-(1→6)-D-glucan presented anticoagulant activity as demonstrated by the increase in dose dependence of APTT and TT, and these actions most likely occurred because of the inserted sulfonate groups on the polysaccharide. The lasiodiplodan did not inhibit the coagulation tests. PMID:23399236

  3. Manipulating the surface active and anticoagulant properties of heparin through amphiphilic molecular constructs

    Science.gov (United States)

    Mintz, Rosita Candida

    Cardiovascular devices implanted within the vasculature are subjected to non-specific adsorption of plasma proteins. This initiates the blood coagulation cascade and platelet adhesion and activation, leading to thrombus formation. In this thesis Heparin Alkyl Diblock (HAD) surfactants were developed to improve the blood compatibility of cardiovascular biomaterials. The material designs involved using heparin, a natural anticoagulant, to inhibit coagulation pathway enzymes and mimic the cell glycocalyx to provide a repulsive force field to inhibit non-specific protein adsorption. Type AB linear (HAD Cn, n = 6,10,12,18) and branched (HAD nx 18, n = 2,3,4) heparin surfactants were synthesized by end point coupling primary and secondary alkyl amines to heparin via reductive amination. Surfactant yields (83--4%) and anticoagulant activity (149.8 +/- 3.7--39.6 +/- 0.6 IU/mg) decreased with increased branching and hydrocarbon number. Surfactant adsorption, self assembly and molecular packing of HAD surfactants at the air/liquid and liquid/solid interface were a function of the number of hydrocarbons in the surfactant alkyl segment and the presence or absence of an ionic liquid phase. Increased molecular packing was observed at the air/PBS and PBS/graphite interface, relative to aqueous interfaces, resulting from buffer cations shielding heparin's negatively charged sulfate and carboxyl groups. At the PBS/graphite interface, the surfactant's apparent heparin head group cross section decreased in diameter (1.84 to 1.05 nm) and increased in tilt angle (75.7 to 81.9°) with increasing alkyl carbon number (n = 6 to 18). The heparin head group reached a minimum diameter, equivalent to the surfactant's diameter at the air/PBS interface (0.57 nm) just prior to 36 hydrocarbons in the surfactant. For surfactants with 36 to 78 hydrocarbons, the surfactant's heparin head group oriented normal to the graphite surface and alkyl overlap or interdigitation increased (0.02 to 0.59 nm

  4. Chemical Characteristics and Anticoagulant Activities of Two Sulfated Polysaccharides from Enteromorpha linza(Chlorophyta)

    Institute of Scientific and Technical Information of China (English)

    QI Xiaohui; MAO Wenjun; CHEN Yin; CHEN Yanli; ZHAO Chunqi; LI Na; WANG Chunyan

    2013-01-01

    Two sulfated polysaccharides,designated MP and SP,were extracted from the marine green alga Enteromorpha linza using hot water and then purified using ion-exchange and size-exclusion chromatography.The anticoagulant activities of MP and SP were examined by determination of their activated partial thromboplastin time (APTT),thrombin time (TT) and prothrombin time (PT) using human plasma.Results showed that MP and SP were composed of abundant rhamnose with small amounts of xylose and glucuronic acid,whereas SP also contained a small amount of galactose.Approximate molecular weights of MP and SP were 535 and 502kDa,respectively.As compared with SP,MP had higher contents of sulfate ester (19.0%) and uronic acid (14.9%).The MP mainly consisted of (1→4)-linked rhamnose residues with partially sulfated groups at the C-3 position,and small amounts of (1→3,4)-linked rhamnose,(1→2,4)-linked rhamnose,(1→4)-linked glucuronic acid and (1→4)-linked xylose residues.The SP contained abundant (1→4)-linked rhamnose with minor amounts of (1→3)-linked rhamnose,(1→3,4)-linked rhamnose,(1→2,4)-linked rhamnose,(1→4)-linked glucuronic acid,(1→4)-linked xylose,and (1→3)-linked galactose residues.The sulfate groups were mainly located at C-3 of (1→4)-linked rhamnose residues.Both MP and SP,in particular the former,effectively prolonged APTT and TT.This work demonstrates that MP and SP have unique structural characteristics distinct from those of other sulfated polysaccharides from Enteromorpha.The MP is a potential source of anticoagulant,and the difference in anticoagulant activities of the two sulfated polysaccharides is directly linked to the discrepancy of their chemical features.

  5. Dissociation of activated protein C functions by elimination of protein S cofactor enhancement.

    LENUS (Irish Health Repository)

    Harmon, Shona

    2008-11-07

    Activated protein C (APC) plays a critical anticoagulant role in vivo by inactivating procoagulant factor Va and factor VIIIa and thus down-regulating thrombin generation. In addition, APC bound to the endothelial cell protein C receptor can initiate protease-activated receptor-1 (PAR-1)-mediated cytoprotective signaling. Protein S constitutes a critical cofactor for the anticoagulant function of APC but is not known to be involved in regulating APC-mediated protective PAR-1 signaling. In this study we utilized a site-directed mutagenesis strategy to characterize a putative protein S binding region within the APC Gla domain. Three single amino acid substitutions within the APC Gla domain (D35T, D36A, and A39V) were found to mildly impair protein S-dependent anticoagulant activity (<2-fold) but retained entirely normal cytoprotective activity. However, a single amino acid substitution (L38D) ablated the ability of protein S to function as a cofactor for this APC variant. Consequently, in assays of protein S-dependent factor Va proteolysis using purified proteins or in the plasma milieu, APC-L38D variant exhibited minimal residual anticoagulant activity compared with wild type APC. Despite the location of Leu-38 in the Gla domain, APC-L38D interacted normally with endothelial cell protein C receptor and retained its ability to trigger PAR-1 mediated cytoprotective signaling in a manner indistinguishable from that of wild type APC. Consequently, elimination of protein S cofactor enhancement of APC anticoagulant function represents a novel and effective strategy by which to separate the anticoagulant and cytoprotective functions of APC for potential therapeutic gain.

  6. Daboxin P, a Major Phospholipase A2 Enzyme from the Indian Daboia russelii russelii Venom Targets Factor X and Factor Xa for Its Anticoagulant Activity

    Science.gov (United States)

    Iyer, Janaki Krishnamurthy; Shih, Norrapat; Majumder, Munmi; Mattaparthi, Venkata Satish Kumar; Mukhopadhyay, Rupak; Doley, Robin

    2016-01-01

    In the present study a major protein has been purified from the venom of Indian Daboia russelii russelii using gel filtration, ion exchange and Rp-HPLC techniques. The purified protein, named daboxin P accounts for ~24% of the total protein of the crude venom and has a molecular mass of 13.597 kDa. It exhibits strong anticoagulant and phospholipase A2 activity but is devoid of any cytotoxic effect on the tested normal or cancerous cell lines. Its primary structure was deduced by N-terminal sequencing and chemical cleavage using Edman degradation and tandem mass spectrometry. It is composed of 121 amino acids with 14 cysteine residues and catalytically active His48 -Asp49 pair. The secondary structure of daboxin P constitutes 42.73% of α-helix and 12.36% of β-sheet. It is found to be stable at acidic (pH 3.0) and neutral pH (pH 7.0) and has a Tm value of 71.59 ± 0.46°C. Daboxin P exhibits anticoagulant effect under in-vitro and in-vivo conditions. It does not inhibit the catalytic activity of the serine proteases but inhibits the activation of factor X to factor Xa by the tenase complexes both in the presence and absence of phospholipids. It also inhibits the tenase complexes when active site residue (His48) was alkylated suggesting its non-enzymatic mode of anticoagulant activity. Moreover, it also inhibits prothrombinase complex when pre-incubated with factor Xa prior to factor Va addition. Fluorescence emission spectroscopy and affinity chromatography suggest the probable interaction of daboxin P with factor X and factor Xa. Molecular docking analysis reveals the interaction of the Ca+2 binding loop; helix C; anticoagulant region and C-terminal region of daboxin P with the heavy chain of factor Xa. This is the first report of a phospholipase A2 enzyme from Indian viper venom which targets both factor X and factor Xa for its anticoagulant activity. PMID:27089306

  7. Daboxin P, a Major Phospholipase A2 Enzyme from the Indian Daboia russelii russelii Venom Targets Factor X and Factor Xa for Its Anticoagulant Activity.

    Directory of Open Access Journals (Sweden)

    Maitreyee Sharma

    Full Text Available In the present study a major protein has been purified from the venom of Indian Daboia russelii russelii using gel filtration, ion exchange and Rp-HPLC techniques. The purified protein, named daboxin P accounts for ~24% of the total protein of the crude venom and has a molecular mass of 13.597 kDa. It exhibits strong anticoagulant and phospholipase A2 activity but is devoid of any cytotoxic effect on the tested normal or cancerous cell lines. Its primary structure was deduced by N-terminal sequencing and chemical cleavage using Edman degradation and tandem mass spectrometry. It is composed of 121 amino acids with 14 cysteine residues and catalytically active His48 -Asp49 pair. The secondary structure of daboxin P constitutes 42.73% of α-helix and 12.36% of β-sheet. It is found to be stable at acidic (pH 3.0 and neutral pH (pH 7.0 and has a Tm value of 71.59 ± 0.46°C. Daboxin P exhibits anticoagulant effect under in-vitro and in-vivo conditions. It does not inhibit the catalytic activity of the serine proteases but inhibits the activation of factor X to factor Xa by the tenase complexes both in the presence and absence of phospholipids. It also inhibits the tenase complexes when active site residue (His48 was alkylated suggesting its non-enzymatic mode of anticoagulant activity. Moreover, it also inhibits prothrombinase complex when pre-incubated with factor Xa prior to factor Va addition. Fluorescence emission spectroscopy and affinity chromatography suggest the probable interaction of daboxin P with factor X and factor Xa. Molecular docking analysis reveals the interaction of the Ca+2 binding loop; helix C; anticoagulant region and C-terminal region of daboxin P with the heavy chain of factor Xa. This is the first report of a phospholipase A2 enzyme from Indian viper venom which targets both factor X and factor Xa for its anticoagulant activity.

  8. Recombinant nematode anticoagulant protein c2 inhibits cell invasion by decreasing uPA expression in NSCLC cells.

    Science.gov (United States)

    Tong, Yu; Yue, Jun; Mao, Meng; Liu, Qingqing; Zhou, Jing; Yang, Jiyun

    2015-04-01

    Nematode anticoagulant protein c2 (NAPc2) is an 85-residue polypeptide originally isolated from the hematophagous hookworm, Ancylostoma caninum. Several studies have shown that rNAPc2 inhibits the growth of primary and metastatic tumors in mice independently of its ability to initiate coagulation. We obtained bioactive recombinant rNAPc2 by splicing of the rNAPc2-intein-CBD fusion proteins expressed in E. coli ER2566. In the in vitro assay, rNAPc2 obviously inhibited the invasive ability of non-small cell lung cancer (NSCLC) cells in a dose-dependent manner. Furthermore, rNAPc2 suppressed tumor growth in vivo by daily intraperitoneal injection of rNAPc2 in an NSCLC cell xenograft model of nude mice. Respectively, rNAPc2 downregulated the production of urokinase plasminogen activator (uPA) (P<0.05) and suppressed nuclear factor-κB (NF-κB) activity. We also identified that inhibition of NF-κB activity impaired cell invasion and reduced the uPA production in NSCLC cells. Meanwhile, NF-κB was found to directly bind to the uPA promoter in vitro. These results demonstrated that rNAPc2 inhibits cell invasion at least in part through the downregulation of the NF-κB-dependent metastasis-related gene expression in NSCLC. Our results also suggest that uPA, a known metastasis-promoting gene, is indirectly regulated by rNAPc2 through NF-κB activation. These results indicate that rNAPc2 may be a potent agent for the prevention of NSCLC progression. PMID:25672417

  9. Partial characterization and anticoagulant activity of a heterofucan from the brown seaweed Padina gymnospora

    Directory of Open Access Journals (Sweden)

    Silva T.M.A.

    2005-01-01

    Full Text Available The brown algae Padina gymnospora contain different fucans. Powdered algae were submitted to proteolysis with the proteolytic enzyme maxataze. The first extract of the algae was constituted of polysaccharides contaminated with lipids, phenols, etc. Fractionation of the fucans with increasing concentrations of acetone produced fractions with different proportions of fucose, xylose, uronic acid, galactose, and sulfate. One of the fractions, precipitated with 50% acetone (v/v, contained an 18-kDa heterofucan (PF1, which was further purified by gel-permeation chromatography on Sephadex G-75 using 0.2 M acetic acid as eluent and characterized by agarose gel electrophoresis in 0.05 M 1,3 diaminopropane/acetate buffer at pH 9.0, methylation and nuclear magnetic resonance spectroscopy. Structural analysis indicates that this fucan has a central core consisting mainly of 3-ß-D-glucuronic acid 1-> or 4-ß-D-glucuronic acid 1 ->, substituted at C-2 with alpha-L-fucose or ß-D-xylose. Sulfate groups were only detected at C-3 of 4-alpha-L-fucose 1-> units. The anticoagulant activity of the PF1 (only 2.5-fold lesser than low molecular weight heparin estimated by activated partial thromboplastin time was completely abolished upon desulfation by solvolysis in dimethyl sulfoxide, indicating that 3-O-sulfation at C-3 of 4-alpha-L-fucose 1-> units is responsible for the anticoagulant activity of the polymer.

  10. Protein C activity in dogs envenomed by Vipera palaestinae.

    Science.gov (United States)

    Hadar, Gil; Kelmer, Efrat; Segev, Gilad; Bruchim, Yaron; Aroch, Itamar

    2014-09-01

    Vipera palaestinae is responsible for most envenomations in humans and domestic animal in Israel. Its venom has pro- and anticoagulant properties. Protein C is a major natural anticoagulant, preventing excess clotting and thrombosis. This study investigated protein C activity and its prognostic value, as well as several other hemostatic analytes in dogs (Canis familiaris) accidently envenomed by V. palaestinae. Protein C activity was compared between envenomed dogs and 33 healthy control dogs. Mean protein C was lower in dogs envenomed by V. palaestinae compared to controls (12.9% vs. 22.9%, respectively; P Dogs diagnosed with consumptive coagulopathy (14%) tended to have lower protein C activity compared to others; however, their mortality did differ from that of other dogs. This is the first study assessing protein C activity in V. palaestinae victims. Decreased protein C activity in such dogs may play a role in formation of thrombosis and hemostatic derangement as well as inflammation in V. palaestinae envenomations.

  11. 正常妊娠妇女血中活化的蛋白C抵抗、狼疮样抗凝物质与血栓前状态分子标志物测定%Measurement of activated protein C resistance, lupus-like anticoagulant and prethrombotic markers in normal gestation

    Institute of Scientific and Technical Information of China (English)

    徐勇; 霍梅; 余涟; 叶素丹; 谢康云

    2001-01-01

    目的 研究活化的蛋白C抵抗(Activated protein Cresistance,APC-R)在正常妊娠中的发生情况,探讨狼疮抗凝物质(Lupus-like anticoagulant,LA)对妊娠性APC-R的影响及二者与凝血酶生成、继发性纤溶的关系。方法 采用APTT-APC法检测APC-R、dRVVT 法测定LA水平,并用ELISA法测定了凝血酶原片段F1+2和D-二聚体(D-dimer,D-D)的含量。结果 检测30例正常妇女对照(NC)和50例正常妊娠妇女,NC组APC-R比率为2.88±0.37,NP组为2.04±0.31(APC-R阳性率为42%);NC组LA阳性率为0,NP组为36.7%;NC组F1+2为(0.734±0.42)nmol/L,NP组为(1.05±0.69)nmol/L;NC组D-D为(0.48±0.05)mg/L,NP组为(0.63±0.11)mg/L;NP组的APC比率、F1+2和D-D的测定结果均较NC组有显著性差异。结论 妊娠可能发生与LA升高有关的APC-R,并导致了凝血酶激活物生成增加以及凝血酶、纤溶酶的激活和继发性纤溶的发生。%Objective To investigate the activated proteinCresistance(APC-R)occurred in normal pregnancy women and the effect of lupus-like anticoagulant(LA) on it,as well as to discuss the relationships between them and coagulation / fibrinolysis activation.Methods APC sensitivity ratio was assessed using APTT-APC method, LA was measured using dRVVT method,prothrombin fragment F1+2and D-dimer were assayed using ELISA Kits.Results 30 normal women controls(NC group)and 50 normal pregnancy women at 28~32 week's gestation(NP group)were measured.We found lower APC sensitivity ratio in normal group(2.04±0.31)than that in normal group (2.88±0.37).None LA positive was found in normal group but there were 36% LA positive samples in normal group.The F1+2and D-dimer levels in normal group were (0.73±0.42)nmol/L and (0.48±0.05)mg/L respectively,whereas were significant increased in NP group(1.05±0.69)nmol/L and (0.63±0.11)mg/L,respectively.Conclusion Normal gestation is associated with a decreased APC sensitivity ratio,which may be related to the increase of LA level

  12. Antibacterial and anticoagulant activities of coumarins isolated from the flowers of Magydaris tomentosa.

    Science.gov (United States)

    Rosselli, Sergio; Maggio, Antonella; Bellone, Gabriella; Formisano, Carmen; Basile, Adriana; Cicala, Carla; Alfieri, Alessio; Mascolo, Nicola; Bruno, Maurizio

    2007-02-01

    The phytochemical investigation of the acetone and methanol extracts of the flowers of Magydaris tomentosa (Desf.) DC afforded six known coumarins as well as (+)-meranzin hydrate (7), not previously reported as a natural product. The antibacterial activity of umbelliprenin (1), osthol (2), imperatorin (3), citropten (4) and (+)-meranzin hydrate (7) was tested against Gram-positive and Gram-negative bacteria. All coumarins (1-7) isolated in this study inhibited growth of all bacterial strains tested (MIC between 16 and 256 microg/mL), the most active being imperatorin (3) (MICs between 32 and 128 microg/mL) and citropten (4) (MICs between 16 and 256 microg/mL). The anticoagulant activity of compounds 1-4 and 7 was also evaluated. PMID:17128388

  13. Optimization of chemical sulfation, structural characterization and anticoagulant activity of Agaricus bisporus fucogalactan.

    Science.gov (United States)

    Román, Yony; Iacomini, Marcello; Sassaki, Guilherme L; Cipriani, Thales R

    2016-08-01

    A fucogalactan (E) was isolated from aqueous extract of Agaricus bisporus. The monosaccharide composition, methylation, and NMR analyses showed it is constituted by a (1→6)-linked α-d-Galp main-chain, partially methylated at O-3, and partially substituted at O-2 by non-reducing end-units of α-l-Fucp or α-d-Galp. HPSEC analysis showed it had Mw of 1.28×10(4)gmol(-1). The polysaccharide was sulfated modifying reaction time, molar ratio of sulfation agent to hydroxyl group on the polysaccharide (ηClSO3H/OH ratio), and ratio of total reaction volume to weight of sample (VT/w ratio; μLmg(-1)). The degree of substitution (DS) was evaluated for all sulfated derivatives. The sulfated fucogalactan with the highest DS value (2.83) had the best anticoagulant activity on Activated Partial Thromboplastin Time (APTT) and Protrombin Time (PT) assays. This sulfated fucogalactan, named E100, was obtained with the optimal conditions of ηClSO3H/OH ratio of 18, VT/w ratio of 100, in 6h of reaction. The results showed that E100 produces a linear increment of APTT for concentrations of 15-45μgmL(-1), whereas PT was almost constant between 20 and 400μgmL(-1), suggesting an anticoagulant activity via inhibition of the intrinsic pathway of blood coagulation. NMR and methylation analyses showed that α-d-Galp units of the main chain were greatly sulfated on 2-O-, 3-O-, and 4-O-positions. PMID:27112883

  14. Study on extraction of agaropectin from Gelidium amansii and its anticoagulant activity

    Institute of Scientific and Technical Information of China (English)

    QI Huimin; LI Daxin; ZHANG Jingjing; LIU Li; ZHANG Quanbin

    2008-01-01

    Gelidium amansii agar was fractionated on DEAE-cellulose and four fractions were obtained sequentially.The yields of 1.0mol/L NaCl fraction and 2.5mol/L NaCl fraction were 2.80% and 2.03%.They are highly sulfated agar,and named as agaropectin with sulfate content being 22.8% and 32.5%,respectively.The anticoagulant experiment results show that agaropectin could effectively prolong the coagulation time in a dose-dependent manner in vitro.Agaropection could be absorbed and effectively prolong the plasma coagulation time in vivo.After intragastric administration at the doses of 100,200,and 400mg/kg·d in rats for 15 days,TT (thrombin time),CT (coagulation time),PT (prothrombin time),and APTT (activated partial thromboplastin time) could be effectively prolonged and the plasma Fib level could be significantly lowered.

  15. Review: anticoagulation for haemodialysis.

    Science.gov (United States)

    Suranyi, Michael; Chow, Josephine S F

    2010-06-01

    The coagulation cascade is complex but well studied. Dialysis membranes and lines are inherently pro-coagulant and activate both the intrinsic and extrinsic pathways of coagulation, as well as platelets and other circulating cellular elements. To provide safe and effective dialysis, appropriate anticoagulant measures must be applied. Haemodialysis, including anticoagulation, is prescribed by dialysis doctors but delivered by dialysis nurses. The main agents used in clinical practice for anticoagulation during haemodialysis are unfractionated heparin (UF heparin) and low-molecular-weight heparin (LMWH). LMWH has a number of potential advantages, apart from cost. One of the most serious complications of the use of any form of heparin is heparin-induced thrombocytopaenia (HIT) Type II, which occurs more commonly with UF heparin than LMWH. HIT Type II risks severe morbidity and mortality and is challenging to treat successfully in both the acute and chronic phase. In HIT Type II anticoagulation must be delivered without heparin. A wide array of newer anticoagulants are becoming progressively available, each with unique advantages and disadvantages. In maintenance haemodialysis patients with an increased risk of bleeding, a 'no heparin' dialysis may be undertaken, or regional anticoagulation considered. Because this aspect of dialysis is so important to the safe and effective delivery of haemodialysis therapy, dialysis clinicians need to review and update their knowledge of dialysis anticoagulation on a regular basis. PMID:20609088

  16. Novel branch patterns and anticoagulant activity of glycosaminoglycan from sea cucumber Apostichopus japonicus.

    Science.gov (United States)

    Yang, Jie; Wang, Yuanhong; Jiang, Tingfu; Lv, Zhihua

    2015-01-01

    A novel glucosidic pattern of fucose branches was found in the glycosaminoglycan from the sea cucumber Apostichopus japonicus in China. The methylation of desulfated/carboxyl-reduced polysaccharides and analysis of unsaturated disaccharides generated from the enzymolysis of the defucosed polysaccharides demonstrated that the branch is formed by one fucopyranosyl residue, 46.5% of which is linked through the O-3 position of β-D-glucuronic acid, while 8.7% and 43.9% are linked through the O-6 and O-4 positions of the N-acetylgalactosamine moiety. The β-D-glucuronic acid, N-acetyl-β-D-galactosamine, α-L-fucose and sulfate ester with the molecular ratio of 0.97:1.00:1.13:3.85 composed the backbone → 4)GlcUAβ(1 → 3)GalNAcβ(1 → and sulfated fucose branches. The sulfation patterns of fucose branches and the linkage pattern of the backbone structure were determined by 1/2 dimension NMR. The most abundant branch species were 2,4-di-O-sulfated and 3,4-di-O-sulfated fucose, but 4-mono-O-sulfated residue was also present. The structure of presently obtained glycosaminoglycan is different from that previously obtained from Stichopus japonicus (Kariya et al., Carbohyd. Res. 297 (1997) 273-279), which suggests that the structures of glycosaminoglycans from the same species of different regions somehow differ. The anticoagulant assay indicated that the polysaccharide possessed a high anticoagulant activity and the sulfated fucose branches were essential to the activity. PMID:25453278

  17. Synthesis and in Vitro and in Vivo Anticoagulant and Antiplatelet Activities of Amidino- and Non-Amidinobenzamides

    Directory of Open Access Journals (Sweden)

    Soo Hyun Lee

    2016-05-01

    Full Text Available Three amidino- and ten non-amidinobenzamides were synthesized as 3-aminobenzoic acid scaffold-based anticoagulant and antiplatelet compounds. The anticoagulant activities of thirteen synthesized compounds 1–13, and 2b and 3b as prodrugs were preliminary evaluated by screening the prolongation of activated partial thromboplastin time (aPTT and prothrombin time (PT in vitro. From the aPTT results obtained, two amidinobenzamides, N-(3′-amidinophenyl-3-(thiophen-2′′-ylcarbonylamino benzamide (1, 33.2 ± 0.7 s and N-(4′-amidinophenyl-3-(thiophen-2′′-ylcarbonylamino benzamide (2, 43.5 ± 0.6 s were selected to investigate the further anticoagulant and antiplatelet activities. The aPTT results of 1 (33.2 ± 0.7 s and 2 (43.5 ± 0.6 s were compared with heparin (62.5 ± 0.8 s in vitro at 30 μM. We investigated the effect of 1 and 2 on blood anticoagulant activity (ex vivo and on tail bleeding time (in vivo on mice. A tail cutting/bleeding time assay revealed that both 1 and 2 prolonged bleeding time in mice at a dose of 24.1 g/mouse and above. Compounds 1 and 2 dose-dependently inhibited thrombin-catalyzed fibrin polymerization and platelet aggregation. In addition, 1 and 2 were evaluated on the inhibitory activities of thrombin and FXa as well as the generation of thrombin and FXa in human umbilical vein endothelial cells (HUVECs. Collectively, 1 and 2 possess some antiplatelet and anticoagulant activities and offer a basis for development of a novel antithrombotic product.

  18. Characterization of cDNA encoding human placental anticoagulant protein (PP4): Homology with the lipocortin family

    Energy Technology Data Exchange (ETDEWEB)

    Grundmann, U.; Abel, K.J.; Bohn, H.; Loebermann, H.; Lottspeich, F.; Kuepper, H. (Research Institutes, Postfach (West Germany))

    1988-06-01

    A cDNA library prepared from human placenta was screened for sequences encoding the placental protein 4 (PP4). PP4 is an anticoagulant protein that acts as an indirect inhibitor of the thromboplastin-specific complex, which is involved in the blood coagulation cascade. Partial amino acid sequence information from PP4-derived cyanogen bromide fragments was used to design three oligonucleotide probes for screening the library. From 10{sup 6} independent recombinants, 18 clones were identified that hybridized to all three probes. These 18 recombinants contained cDNA inserts encoding a protein of 320 amino acid residues. In addition to the PP4 cDNA the authors identified 9 other recombinants encoding a protein with considerable similarity (74%) to PP4, which was termed PP4-X. PP4 and PP4-X belong to the lipocortin family, as judged by their homology to lipocortin I and calpactin I.

  19. Characterization of cDNA encoding human placental anticoagulant protein (PP4): Homology with the lipocortin family

    International Nuclear Information System (INIS)

    A cDNA library prepared from human placenta was screened for sequences encoding the placental protein 4 (PP4). PP4 is an anticoagulant protein that acts as an indirect inhibitor of the thromboplastin-specific complex, which is involved in the blood coagulation cascade. Partial amino acid sequence information from PP4-derived cyanogen bromide fragments was used to design three oligonucleotide probes for screening the library. From 106 independent recombinants, 18 clones were identified that hybridized to all three probes. These 18 recombinants contained cDNA inserts encoding a protein of 320 amino acid residues. In addition to the PP4 cDNA the authors identified 9 other recombinants encoding a protein with considerable similarity (74%) to PP4, which was termed PP4-X. PP4 and PP4-X belong to the lipocortin family, as judged by their homology to lipocortin I and calpactin I

  20. Comparative Assessment of the Anticoagulant Activity of Rivaroxaban and Dabigatran in Patients With Nonvalvular Atrial Fibrillation: A Noninterventional Study.

    Science.gov (United States)

    Tsantes, Argirios E; Kyriakou, Elias; Ikonomidis, Ignatios; Katogiannis, Konstantinos; Papadakis, Ioannis; Douramani, Panagiota; Kopterides, Petros; Kapsimali, Violetta; Lekakis, John; Tsangaris, Iraklis; Bonovas, Stefanos

    2016-04-01

    There is a shortage of data in everyday clinical practice about the anticoagulant effects caused by the new oral anticoagulants (NOAs). Our aim was to estimate the intensity of anticoagulant activity induced by rivaroxaban 20 mg qd and dabigatran 110 mg bid among patients with nonvalvular atrial fibrillation (NV-AF).We studied 20 patients with NV-AF treated with dabigatran, and 20 patients treated with rivaroxaban. We performed conventional coagulation tests, thrombin generation (TG) test, thromboelastometry (ROTEM), and epinephrine-induced light transmission aggregometry (LTA) in all 40 patients and 20 controls. Hemoclot Thrombin Inhibitors (HTI) and Factor Xa Direct Inhibitor (DiXaI) assay were used to measure dabigatran and rivaroxaban plasma levels, respectively.Measurements of all assays estimating anticoagulant activity across the 2 patient groups were similar, except for aPTT. Patients on dabigatran exhibited statistically significantly prolonged aPTT values (P dabigatran also showed decreased aggregation compared to those on rivaroxaban (P = 0.045). Regarding the TG test, there was no association between endogenous thrombin potential (ETP) and rivaroxaban plasma levels (P = 0.33) as opposed to dabigatran levels (P dabigatran as compared to rivaroxaban.

  1. Anticoagulant, Antioxidant and Antitumor Activities of Heterofucans from the Seaweed Dictyopteris delicatula

    Directory of Open Access Journals (Sweden)

    Hugo Alexandre Oliveira Rocha

    2011-05-01

    Full Text Available In the present study, six families of sulfated polysaccharides were obtained from seaweed Dictyopteris delicatula by proteolytic digestion, followed by acetone fractionation and molecular sieving on Sephadex G-100. Chemical analyses demonstrated that all polysaccharides contain heterofucans composed mainly of fucose, xylose, glucose, galactose, uronic acid, and sulfate. The fucans F0.5v and F0.7v at 1.0 mg/mL showed high ferric chelating activity (~45%, whereas fucans F1.3v (0.5 mg/mL showed considerable reducing power, about 53.2% of the activity of vitamin C. The fucan F1.5v presented the most prominent anticoagulant activity. The best antiproliferative activity was found with fucans F1.3v and F0.7v. However, F1.3v activity was much higher than F0.7v inhibiting almost 100% of HeLa cell proliferation. These fucans have been selected for further studies on structural characterization as well as in vivo experiments, which are already in progress.

  2. The role of activated protein C in cancer progression

    NARCIS (Netherlands)

    G.L. van Sluis; H.R. Büller; C.A. Spek

    2010-01-01

    Activated protein C (APC) is best known as a natural anticoagulant that also has direct cell signaling properties which (among others) enhance vascular barrier function. We recently established the relevance of APC-induced barrier enhancement by showing that endogenous APC limits cancer cell extrava

  3. Role of thrombus precursor protein in assessment of anticoagulation in patients with atrial fibrillation after mechanical heart valve replacement

    Institute of Scientific and Technical Information of China (English)

    秦川; 肖颖彬; 陈林; 王学锋; 钟前进

    2004-01-01

    Objective: To explore the role of thrombus precursor protein (TpP) in assessment of anticoagulation and predict the risk of thromboembolism in the patients with atrial fibrillation (AF) after mechanical heart valve replacement. Methods: TpP plasma concentration and international normalization ratio (INR) were measured in 45 patients with atrial fibrillation and 45 patients with sinus rhythm both after mechanical heart valve replacement. Twenty patients with non-valvular heart diseases were selected as the control. Furthermore, the patients with AF were divided into groups based on different TpP plasma concentration and TpP plasma concentration and INR were analyzed. Results: After mechanical heart valve replacement, those with AF had higher TpP plasma concentration than those with sinus rhythm. It was found that discordancy existed between INR and TpP plasma concentration in the patients with AF. There were 28 AF patients with TpP plasma concentration lower than 6 μg/ml and without bleeding, who might be at the optimal anticoagulant state. The 95% confidence of the mean INR value was 1.90-2.30 in these patients and TpP plasma concentration was between 2.84-5.74 μg/ml. Conclusion: Patients with AF might face higher risk of thromboembolism after mechanical valve replacement; INR between 1.90-2.30 and TpP plasma concentration between 2.84-6 μg/ml might be the optimal anticoagulant range for patients with AF after mechanical valve replacement.

  4. Lupus anticoagulant, disease activity and low complement in the first trimester are predictive of pregnancy loss

    OpenAIRE

    Mankee, Anil; Petri, Michelle; Magder, Laurence S.

    2015-01-01

    Introduction Multiple factors, including proteinuria, antiphospholipid syndrome, thrombocytopenia and hypertension, are predictive of pregnancy loss in systemic lupus erythematosus (SLE). In the PROMISSE study of predictors of pregnancy loss, only a battery of lupus anticoagulant tests was predictive of a composite of adverse pregnancy outcomes. We examined the predictive value of one baseline lupus anticoagulant test (dilute Russell viper venom time) with pregnancy loss in women with SLE. Me...

  5. Anticoagulant activity of a sulfated polysaccharide isolated from the green seaweed Caulerpa cupressoides

    Directory of Open Access Journals (Sweden)

    José Ariévilo Gurgel Rodrigues

    2011-08-01

    Full Text Available The aim of this study was to evaluate certain molecular characteristics of a sulfated polysaccharide (SPs with anticoagulant properties, isolated from Caulerpa cupressoides (Chlorophyta. Crude SPs were extracted by proteolytic digestion (papain, followed by ion-exchange chromatography on a DEAE-cellulose column. The fractions obtained were analyzed for molecular mass, 0.5% agarose gel electrophoresis and chemical composition. The activated partial thromboplastin time (APTT test was applied using normal human plasma and standard heparin (HEP (193 IU mg-1. The yield was ~ 3%, and the chromatography procedure separated the material into three different SP fractions (F I, F II and F III, eluted at the concentrations of 0.50, 0.75 and 1.00 M of NaCl, respectively. Only fraction F II was active (24.62 IU mg-1, with high sulfate content (23.79% and number of molecular mass peaks. Therefore, the APTT of a fraction isolated from C. cupressoides was less potent than HEP.

  6. Anticoagulant and antithrombotic activities of low-molecular-weight propylene glycol alginate sodium sulfate (PSS).

    Science.gov (United States)

    Xin, Meng; Ren, Li; Sun, Yang; Li, Hai-hua; Guan, Hua-Shi; He, Xiao-Xi; Li, Chun-Xia

    2016-05-23

    Propylene glycol alginate sodium sulfate (PSS), a sulfated polysaccharide derivative, has been used as a heparinoid drug to prevent and treat hyperlipidemia and ischemic cardio-cerebrovascular diseases in China for nearly 30 years. To extend the applications of PSS, a series of low-molecular-weight PSSs (named FPs) were prepared by oxidative-reductive depolymerization, and the antithrombotic activities were investigated thoroughly in vitro and in vivo. The bioactivity evaluation demonstrated a positive correlation between the molecular weight and the anticoagulant and antithrombotic activities of FPs. FPs could prolong the APTT and clotting time and reduce platelet aggregation significantly. FPs could also effectively inhibit factor IIa in the presence of AT-III and HC-II. FPs decreased the wet weights and lengths of the thrombus and increased occlusion times in vivo. FP-6k, a PSS fragment with a molecular weight of 6 kDa, is an optimal antithrombotic candidate for further study and showed little chance for hemorrhagic action. PMID:26974373

  7. A novel prothrombin time assay for assessing the anticoagulant activity of oral factor Xa inhibitors.

    Science.gov (United States)

    Barrett, Yu Chen; Wang, Zhaoqing; Knabb, Robert M

    2013-09-01

    Conventional prothrombin time (PT) assays have limited sensitivity and dynamic range in monitoring the anticoagulant activity of direct factor Xa inhibitors. Hence, new assays are needed. We modified a PT assay by adding calcium chloride (CaCl2) to the thromboplastin reagent to increase assay dynamic range and improve sensitivity. Effects of calcium and sodium ion concentrations, and sample handling, were evaluated to optimize assay performance. Increasing concentrations of calcium ions produced progressive increases in PT across the factor Xa inhibitor concentrations of 0 to 2500 nmol/L for razaxaban and apixaban. The greatest effect was seen when the thromboplastin reagent was diluted 1:2.25 with 100 mmol/L CaCl2 (thus selected for routine use). The optimized assay showed an interassay precision of 1.5 to 9.3 percentage coefficient of variation (%CV) for razaxaban and 3.1 to 4.6 %CV for apixaban. We conclude that the modified PT assay is likely to be suitable as a pharmacodynamic marker for activity at therapeutic concentrations of factor Xa inhibitors.

  8. Depolymerization of Fucosylated Chondroitin Sulfate with a Modified Fenton-System and Anticoagulant Activity of the Resulting Fragments

    Science.gov (United States)

    Li, Jun-hui; Li, Shan; Zhi, Zi-jian; Yan, Lu-feng; Ye, Xing-qian; Ding, Tian; Yan, Lei; Linhardt, Robert John; Chen, Shi-guo

    2016-01-01

    Fucosylated chondroitin sulfate (fCS) from sea cucumber Isostichopus badionotus (fCS-Ib) with a chondroitin sulfate type E (CSE) backbone and 2,4-O-sulfo fucose branches has shown excellent anticoagulant activity although has also show severe adverse effects. Depolymerization represents an effective method to diminish this polysaccharide’s side effects. The present study reports a modified controlled Fenton system for degradation of fCS-Ib and the anticoagulant activity of the resulting fragments. Monosaccharides and nuclear magnetic resonance (NMR) analysis of the resulting fragments indicate that no significant chemical changes in the backbone of fCS-Ib and no loss of sulfate groups take place during depolymerization. A reduction in the molecular weight of fCS-Ib should result in a dramatic decrease in prolonging activated partial thromboplastin time and thrombin time. A decrease in the inhibition of thrombin (FIIa) by antithromin III (AT III) and heparin cofactor II (HCII), and the slight decrease of the inhibition of factor X activity, results in a significant increase of anti-factor Xa (FXa)/anti-FIIa activity ratio. The modified free-radical depolymerization method enables preparation of glycosaminoglycan (GAG) oligosaccharides suitable for investigation of clinical anticoagulant application. PMID:27657094

  9. Lupus anticoagulant in human immunodeficiency virus -infected patients on highly active antiretroviral therapy

    Directory of Open Access Journals (Sweden)

    Awodu Omolade

    2010-01-01

    Full Text Available Background: Lupus anticoagulant (LA is a heterogeneous group of antibodies that causes a variety of clinical and laboratory effects; has been described in infections such as human immunodeficiency virus. LA has not been previously described in Nigerians with human immunodeficiency virus infection on highly active antiretroviral therapy (HAART. Aim: To determine the frequency of LA in patients infected with the human immunodeficiency virus on HAART. Methods: Cross sectional study of patients with human immunodeficiency virus infection undergoing HAART at a tertiary hospital in Nigeria. Screening for LA was done using the activated partial thromboplastin time (aPTT and kaolin clotting time (KCT. Mixing experiments were conducted on samples with prolonged clotting time. KCT ratio was calculated. A positive result was taken as KCT ratio greater than or equal to 1.2. Fisher′s exact test was used to test the association between LA and sex. Association between aPTT and KCT was tested according to Pearson. P-value < 0.05 was considered significant. Results: Fifty-eight patients aged 18- 60 years were studied, comprising of 28 males (mean age 40.50 plus/minus 8.8 years and 30 females (mean age 35.4 plus/minus 9.02. Frequency of LA among human immunodeficiency infected patients was 5.2%, (frequency in males and females were 3.6 and 6.7 % respectively. This was lower than 46% reported in patients not on HAART. There was no statistically significant difference in LA prevalence between males and females P greater than0.05. A positive correlation was observed between the clotting tests aPTT and KCT (r is equal to 0.9406, p less than 0.0001. Conclusion: HAART may prevent development of LA in HIV-infected patients.

  10. Distinct structures of the α-fucose branches in fucosylated chondroitin sulfates do not affect their anticoagulant activity.

    Science.gov (United States)

    Santos, Gustavo R C; Glauser, Bianca F; Parreiras, Luane A; Vilanova, Eduardo; Mourão, Paulo A S

    2015-10-01

    Fucosylated chondroitin sulfate (FCS) is a glycosaminoglycan found in sea cucumbers. It has a backbone like that of mammalian chondroitin sulfate (4-β-d-GlcA-1→3-β-d-GalNAc-1)n but substituted at the 3rd position of the β-d-glururonic acid residues with α-fucose branches. The structure of these branches varies among FCSs extracted from different species of sea cucumbers, as revealed by solution NMR spectroscopy. Some species (Isostichopus badionotus and Patalus mollis) contain branches formed by single α-fucose residues but with variable sulfation patterns (2,4-, 3,4- and 4-sulfation). FCS from Ludwigothurea grisea is distinguished because it contains preponderant branches formed by disaccharide units containing non-sulfated and 3-sulfated α-fucose units at the reducing and non-reducing ends, respectively. Despite the structural variability on their α-fucose branches, these FCSs have similar anticoagulant action on assays using purified reagents. They have serpin-dependent and serpin-independent effects. Pharmacological assays using experimental animals showed that the three types of FCSs have similar antithrombotic effect and bleeding tendency. They also activate factor XII on the same range of concentration. Based on these observations, we proposed that only few sulfated α-fucose branches along the FCS chain are enough to assure the binding of this glycosaminoglycan to proteins of the coagulation system. Substitution with additional sulfated α-fucose does not increase further the activity. Overall, the use of FCSs with marked variability on their branches of α-fucose allowed us to establish correlations between structures vs biological effects of these glycosaminoglycans on a more refined basis. It opens new avenues for therapeutic intervention using FCSs.

  11. New anticoagulants.

    Science.gov (United States)

    Weitz, J I; Bates, S M

    2005-08-01

    The limitations of heparin and warfarin have prompted the development of new anticoagulant drugs for prevention and treatment of venous and arterial thromboembolism. Novel parenteral agents include synthetic analogs of the pentasaccharide sequence of heparin that mediates its interaction with antithrombin. Fondaparinux, the first synthetic pentasaccharide, is licensed for prevention of venous thromboembolism (VTE) after major orthopedic surgery and for initial treatment of patients with VTE. Idraparinux, a long-acting pentasaccharide that is administered subcutaneously once-weekly, is being compared with warfarin for treatment of VTE and for prevention of cardioembolic events in patients with atrial fibrillation. New oral anticoagulants include direct inhibitors of thrombin, factor Xa and factor IXa. Designed to provide more streamlined anticoagulation than warfarin, these agents can be given without routine coagulation monitoring. Ximelagatran, the first oral direct thrombin inhibitor, is as effective and safe as warfarin for prevention of cardioembolic events in patients with atrial fibrillation. However, ximelagatran produces a three-fold elevation in alanine transaminase levels in 7.9% of patients treated for more than a month, the long-term significance of which is uncertain. Whether other direct thrombin inhibitors or inhibitors of factors Xa or IXa also have this problem is under investigation. After a brief review of coagulation pathways, this paper focuses on new anticoagulants in advanced stages of clinical testing. PMID:16102051

  12. Fabrication of PP-g-PEGMA-g-heparin and its hemocompatibility: From protein adsorption to anticoagulant tendency

    Science.gov (United States)

    Jin, Jing; Jiang, Wei; shi, Qiang; Zhao, Jie; Yin, Jinghua; Stagnaro, Paola

    2012-05-01

    We described a two-step process to fabricate the heparinized polypropylene (PP) film using cyanuric chloride (CC) as a trifunctional reagent and poly (ethylene glycol) methacrylate (PEGMA) as a spacer. The modified PP films were characterized by attenuated total reflectance FT-IR and X-ray photoelectron spectroscopy; the content of PEGMA and heparin were determined by gravimetric method and a toluidine blue assay, respectively. For the PP-g-PEGMA films, it was found that small size protein BSA tended to adsorb on the surface of low molecular weight monomer grafted PP, whereas big spindle-shaped fibrinogen tended to adsorb on the surface of high molecular weight monomer grafted PP. We gave a definition of anti-protein adsorptive factor r with two model proteins, albumin and fibrinogen. The results by platelet adhesion and plasma recalcification time (PRT) experiments indicated that the factor r could be used to quantitatively evaluate the anticoagulant tendency of PP-g-PEGMA modified films. For the PP-g-PEGMA-g-heparin modified films, the surface was proved to have a high bioactivity by the adsorption of AT III assay and very low platelet adhesion. It indicated that immobilization of heparin on the PP film with PEGMA as a spacer was an effective way to improve the hemocompatibility of PP.

  13. Fabrication of PP-g-PEGMA-g-heparin and its hemocompatibility: From protein adsorption to anticoagulant tendency

    Energy Technology Data Exchange (ETDEWEB)

    Jin Jing [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Jiang Wei, E-mail: wjiang@ciac.jl.cn [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Shi Qiang [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Zhao Jie [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Yin Jinghua, E-mail: yinjh@ciac.jl.cn [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Stagnaro, Paola [Istituto per Io Studio delle Macromolecole, Consiglio Nazionale delle Ricerche, Via de Marini 6, 16149 Genova (Italy)

    2012-05-15

    We described a two-step process to fabricate the heparinized polypropylene (PP) film using cyanuric chloride (CC) as a trifunctional reagent and poly (ethylene glycol) methacrylate (PEGMA) as a spacer. The modified PP films were characterized by attenuated total reflectance FT-IR and X-ray photoelectron spectroscopy; the content of PEGMA and heparin were determined by gravimetric method and a toluidine blue assay, respectively. For the PP-g-PEGMA films, it was found that small size protein BSA tended to adsorb on the surface of low molecular weight monomer grafted PP, whereas big spindle-shaped fibrinogen tended to adsorb on the surface of high molecular weight monomer grafted PP. We gave a definition of anti-protein adsorptive factor r with two model proteins, albumin and fibrinogen. The results by platelet adhesion and plasma recalcification time (PRT) experiments indicated that the factor r could be used to quantitatively evaluate the anticoagulant tendency of PP-g-PEGMA modified films. For the PP-g-PEGMA-g-heparin modified films, the surface was proved to have a high bioactivity by the adsorption of AT III assay and very low platelet adhesion. It indicated that immobilization of heparin on the PP film with PEGMA as a spacer was an effective way to improve the hemocompatibility of PP.

  14. In Vitro Antioxidant, Anticoagulant and Antimicrobial Activity and in Inhibition of Cancer Cell Proliferation by Xylan Extracted from Corn Cobs

    Directory of Open Access Journals (Sweden)

    Hugo Alexandre Oliveira Rocha

    2011-12-01

    Full Text Available Xylan is one of most abundant polymer after cellulose. However, its potential has yet to be completely recognized. Corn cobs contain a considerable reservoir of xylan. The aim of this work was to study some of the biological activities of xylan obtained from corn cobs after alkaline extraction enhanced by ultrasonication. Physical chemistry and infrared analyses showed 130 kDa heteroxylan containing mainly xylose:arabinose: galactose:glucose (5.0:1.5:2.0:1.2. Xylan obtained exhibited total antioxidant activity corresponding to 48.5 mg of ascorbic acid equivalent/g of xylan. Furthermore, xylan displayed high ferric chelating activity (70% at 2 mg/mL. Xylan also showed anticoagulant activity in aPTT test. In antimicrobial assay, the polysaccharide significantly inhibited bacterial growth of Klebsiella pneumoniae. In a test with normal and tumor human cells, after 72 h, only HeLa tumor cell proliferation was inhibited (p < 0.05 in a dose-dependent manner by xylan, reaching saturation at around 2 mg/mL, whereas 3T3 normal cell proliferation was not affected. The results suggest that it has potential clinical applications as antioxidant, anticoagulant, antimicrobial and antiproliferative compounds.

  15. The binding of the anticoagulation factor Ⅰ from the venom of Agkistrodon acutus to activated factor Ⅹ

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Anticoagulation factor Ⅰ (ACF Ⅰ) from the venom of Agkistrodon acutus prolonged plasma prothrombin time (PPT) with dose-dependent manner and exhibited marked anticoagulant activity only at the concentration higher than its critical concentration (12 nmol/L). It was discovered that ACFⅠ formed a 1:1 complex with activated coagulation factor (FⅩa) in the presence of Ca2+ ions by the method of polyacrylamide gel electrophoresis. Both native ACFⅠ and decalcified ACFⅠ failed to form complexes with FⅩa in the absence of Ca2+. Sr2+ ions were able to replace Ca2+ ions in the binding of ACFⅠ to FⅩa, but both Ba2+ ions and Tb3+ ions were ineffective. ACFⅠ was a new member of the Ⅸ/Ⅹ-bp family in the C-type lectin superfamily, and had a amino acid composition similar to the other members of this family. It was composed of 251 amino acid residues with a molecular weight of 29 603.6 u on non-reducing condition, determined by MALDI-TOF-MS, and a molecular weight of 14.7 ku on reducing condition, determined by the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE).

  16. Comparative study of anticoagulant and procoagulant properties of 28 snake venoms from families Elapidae, Viperidae, and purified Russell's viper venom-factor X activator (RVV-X).

    Science.gov (United States)

    Suntravat, Montamas; Nuchprayoon, Issarang; Pérez, John C

    2010-09-15

    Snake venoms consist of numerous molecules with diverse biological functions used for capturing prey. Each component of venom has a specific target, and alters the biological function of its target. Once these molecules are identified, characterized, and cloned; they could have medical applications. The activated clotting time (ACT) and clot rate were used for screening procoagulant and anticoagulant properties of 28 snake venoms. Crude venoms from Daboia russellii siamensis, Bothrops asper, Bothrops moojeni, and one Crotalus oreganus helleri from Wrightwood, CA, had procoagulant activity. These venoms induced a significant shortening of the ACT and showed a significant increase in the clot rate when compared to the negative control. Factor X activator activity was also measured in 28 venoms, and D. r. siamensis venom was 5-6 times higher than those of B. asper, B. moojeni, and C. o. helleri from Wrightwood County. Russell's viper venom-factor X activator (RVV-X) was purified from D. r. siamensis venom, and then procoagulant activity was evaluated by the ACT and clot rate. Other venoms, Crotalus atrox and two Naja pallida, had anticoagulant activity. A significant increase in the ACT and a significant decrease in the clot rate were observed after the addition of these venoms; therefore, the venoms were considered to have anticoagulant activity. Venoms from the same species did not always have the same ACT and clot rate profiles, but the profiles were an excellent way to identify procoagulant and anticoagulant activities in snake venoms. PMID:20677373

  17. Earthworm extracts utilized in the green synthesis of gold nanoparticles capable of reinforcing the anticoagulant activities of heparin

    Science.gov (United States)

    Kim, Hee Kyeong; Choi, Myung-Jin; Cha, Song-Hyun; Koo, Yean Kyoung; Jun, Sang Hui; Cho, Seonho; Park, Youmie

    2013-12-01

    Gold nanoparticles were obtained using a green synthesis approach with aqueous earthworm extracts without any additional reducing or capping agents. The gold nanoparticles were characterized using UV-visible spectrophotometry, high-resolution transmission electron microscopy, atomic force microscopy, field emission scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and inductively coupled plasma mass spectrometry. The anticoagulant activity of the gold nanoparticles was assessed using the activated partial thromboplastin time and was mildly enhanced by combining the gold nanoparticles with heparin. In addition to the generation of spherical nanoparticles with an average diameter of 6.13 ± 2.13 nm, cubic and block-shaped nanoparticles with an average aspect ratio, defined as the length divided by width, of 1.47 were also observed.

  18. Heparins with reduced anti-coagulant activity reduce myocardial reperfusion injury.

    Science.gov (United States)

    Barry, William H; Kennedy, Thomas P

    2011-05-01

    Heparin which is desulfated at the 2-O and 3-O positions (ODSH) has reduced anti-coagulant properties, and reduced interaction with heparin antibodies. Because of the reduced anti-coagulant effect, ODSH can be safely administered to animals and humans intravenously at doses up to 20 mg/kg, resulting in a serum concentration of up to 250µg/ml. Administration of ODSH causes a 35% reduction in infarct size in dogs and pigs subjected to coronary artery occlusion and reperfusion when given 5 min before reperfusion. ODSH has anti-inflamatory effects, manifest as a decrease in neutrophil infiltration into ischemic tissue at high doses, but this effect does not entirely account for the reduction in infarct size. ODSH decreases Na(+) and Ca(2+) loading in isolated cardiac myocytes subjected to simulated ischemia. This effect appears due to an ODSH-induced reduction in an enhanced Na(+) influx via the Na channel in the membrane of cardiac myocyes caused by oxygen radicals generated during ischemia and reperfusion. Reduction in Na(+) influx decreases Ca(2+) loading by reducing Ca2(+) influx via Na/Ca exchange, thus reducing Ca(2+) - dependent reperfusion injury. ODSH does not appear to interact with antibodies to the heparin/platelet factor 4 complex, and does not cause heparin-induced thrombocytopenia. Because of these therapeutic and safety considerations, ODSH would appear to be a promising heparin derivative for prevention of reperfusion injury in humans undergoing thrombolytic or catheter-based reperfusion for acute myocardial infarction. The review article discussed the use of heparin and the discussion of some of the important patents, including: US6489311; US7478358; PCTUS2008070836 and PCTUS2009037836.

  19. MONITORING OF ANTICOAGULATION IN APROTININ-TREATED PATIENTS DURING HEART OPERATION

    NARCIS (Netherlands)

    TABUCHI, N; NJO, TL; TIGCHELAAR, [No Value; HUYZEN, RJ; BOONSTRA, PW; VANOEVEREN, W

    1994-01-01

    Since aprotinin has become extensively used during cardiopulmonary bypass the maintenance of safe anticoagulation is a concern. Aprotinin affects anticoagulation measurement by the activated clotting time. Therefore, a reliable new measurement is needed to monitor anticoagulation during cardiopulmon

  20. 海南水蛭中水蛭素的抗凝活性研究%Study on anticoagulant activity of hirudin in Hainan leech

    Institute of Scientific and Technical Information of China (English)

    刘腾; 符乃光; 李泽友

    2015-01-01

    目的:分析海南水蛭的品种及其中水蛭素的抗凝作用。方法观察海南水蛭的形态特征、薄层色谱图,并采用凝血酶滴定法测定其抗凝活性。结果海南水蛭为菲牛蛭,水蛭素的抗凝活性分别为:全身1174.8 U/g、头部6521.7 U/g、身体308.6 U/g。结论海南水蛭具有很好的抗凝血活性,值得进一步研究开发。%Objective To analyze the species of Hainan leeches and the anticoagulant activity of hirudin. Methods The morphological characteristics and thin-layer chromatogram of Hainan leech were observed. Then anti-coagulant activity was measured with the method of thrombin titration. Results Hainan leeches were Hirudinaria ma-nillensis. The anticoagulant activity of Hainan Leech hirudin was 1 174.8 U/g of whole body, 6 521.7 U/g of the head and 308.6 U/g of the body. Conclusion Hainan leeches have very good anticoagulant activity, which deserve further research and development.

  1. Structural analysis and anticoagulant activities of the novel sulfated fucan possessing a regular well-defined repeating unit from sea cucumber.

    Science.gov (United States)

    Wu, Mingyi; Xu, Li; Zhao, Longyan; Xiao, Chuang; Gao, Na; Luo, Lan; Yang, Lian; Li, Zi; Chen, Lingyun; Zhao, Jinhua

    2015-04-01

    Sulfated fucans, the complex polysaccharides, exhibit various biological activities. Herein, we purified two fucans from the sea cucumbers Holothuria edulis and Ludwigothurea grisea. Their structures were verified by means of HPGPC, FT-IR, GC-MS and NMR. As a result, a novel structural motif for this type of polymers is reported. The fucans have a unique structure composed of a central core of regular (1→2) and (1→3)-linked tetrasaccharide repeating units. Approximately 50% of the units from L. grisea (100% for H. edulis fucan) contain sides of oligosaccharides formed by nonsulfated fucose units linked to the O-4 position of the central core. Anticoagulant activity assays indicate that the sea cucumber fucans strongly inhibit human blood clotting through the intrinsic pathways of the coagulation cascade. Moreover, the mechanism of anticoagulant action of the fucans is selective inhibition of thrombin activity by heparin cofactor II. The distinctive tetrasaccharide repeating units contribute to the anticoagulant action. Additionally, unlike the fucans from marine alga, although the sea cucumber fucans have great molecular weights and affluent sulfates, they do not induce platelet aggregation. Overall, our results may be helpful in understanding the structure-function relationships of the well-defined polysaccharides from invertebrate as new types of safer anticoagulants. PMID:25871288

  2. Structural Analysis and Anticoagulant Activities of the Novel Sulfated Fucan Possessing a Regular Well-Defined Repeating Unit from Sea Cucumber

    Directory of Open Access Journals (Sweden)

    Mingyi Wu

    2015-04-01

    Full Text Available Sulfated fucans, the complex polysaccharides, exhibit various biological activities. Herein, we purified two fucans from the sea cucumbers Holothuria edulis and Ludwigothurea grisea. Their structures were verified by means of HPGPC, FT-IR, GC–MS and NMR. As a result, a novel structural motif for this type of polymers is reported. The fucans have a unique structure composed of a central core of regular (1→2 and (1→3-linked tetrasaccharide repeating units. Approximately 50% of the units from L. grisea (100% for H. edulis fucan contain sides of oligosaccharides formed by nonsulfated fucose units linked to the O-4 position of the central core. Anticoagulant activity assays indicate that the sea cucumber fucans strongly inhibit human blood clotting through the intrinsic pathways of the coagulation cascade. Moreover, the mechanism of anticoagulant action of the fucans is selective inhibition of thrombin activity by heparin cofactor II. The distinctive tetrasaccharide repeating units contribute to the anticoagulant action. Additionally, unlike the fucans from marine alga, although the sea cucumber fucans have great molecular weights and affluent sulfates, they do not induce platelet aggregation. Overall, our results may be helpful in understanding the structure-function relationships of the well-defined polysaccharides from invertebrate as new types of safer anticoagulants.

  3. Annexin A5 anticoagulant activity in children with systemic lupus erythematosus and the association with antibodies to domain I of β2-glycoprotein I.

    Science.gov (United States)

    Wahezi, D M; Ilowite, N T; Wu, X X; Pelkmans, L; Laat, B; Schanberg, L E; Rand, J H

    2013-06-01

    Children with systemic lupus erythematosus (SLE) have a high prevalence of antiphospholipid (aPL) antibodies and are at increased risk for aPL-related thrombosis. We investigated the association between annexin A5 anticoagulant activity and antibodies to the domain I portion of β2-glycoprotein I (anti-DI antibodies), and propose a potential mechanism for the pathogenesis of aPL-related thrombosis. Using samples from 183 children with SLE collected during the Atherosclerosis Prevention in Pediatric Lupus Erythematosus (APPLE) trial, we examined resistance to the anticoagulant effects of annexin A5, using the annexin A5 resistance (A5R) assay, and evaluated for anti-DI IgG antibodies. Children with SLE had higher frequency of anti-D1 antibodies (p = 0.014) and significantly reduced A5R compared to pediatric controls: mean A5R = 172 ± 30% versus 242 ± 32% (p antibodies had significantly lower mean A5R levels compared to those with negative anti-DI antibodies: mean A5R = 155 ± 24% versus 177 ± 30% (p antibodies (p = 0.013) and lupus anticoagulant (LA) (p = 0.036) were both independently associated with reduced A5R. Children with SLE have significantly reduced annexin A5 anticoagulant activity that is associated with the presence of LA and anti-DI antibodies.

  4. Recombinant activated protein C attenuates coagulopathy and inflammation when administered early in murine pneumococcal pneumonia

    NARCIS (Netherlands)

    M. Schouten; C. van 't Veer; J.J.T.H. Roelofs; B. Gerlitz; B.W. Grinnell; M. Levi; T. van der Poll

    2011-01-01

    Recombinant human activated protein C (APC), which has both anticoagulant and anti-inflammatory properties, improves survival of patients with severe sepsis. This beneficial effect is especially apparent in patients with pneumococcal pneumonia. Earlier treatment with APC in sepsis has been associate

  5. Pharmacologic Therapies in Anticoagulation.

    Science.gov (United States)

    Ferreira, Joana Lima; Wipf, Joyce E

    2016-07-01

    Anticoagulants are beneficial for prevention and treatment of venous thromboembolism and stroke prevention in atrial fibrillation. The development of target-specific oral anticoagulants is changing the landscape of anticoagulation therapy and created growing interest on this subject. Understanding the pharmacology of different anticoagulants is the first step to adequately treat patients with best available therapy while avoiding serious bleeding complications. This article reviews the pharmacology of the main anticoagulant classes (vitamin K antagonists, direct oral anticoagulants, and heparins) and their clinical indications based on evidence-based data currently available in the literature. PMID:27235611

  6. Screening of the components with blood-anticoagulant activity from marine algae Sargassum fusiforme and Undaria pinnatifida%羊栖菜和裙带菜中抗凝血活性物质的初步筛选

    Institute of Scientific and Technical Information of China (English)

    刘承初; 周颖; 邬英睿; 甘建红; 周培根

    2004-01-01

    Components with blood-anticoagulant activity were fractionated from marine algae Sargassumfusiforrne and Undaria pinnatifida and the activity of the components was investigated by using the method of bioassay. It was found that the 80% ethanol soluble fraction of Sargassumfusiforme exhibited no blood-anticoagulant activity, while the components obtained from the 80 % ethanol insoluble fraction (hot water extract) gave obvious bloodanticoagulant activity. A further study suggests that the principal component in the hot water extract from Sargassumfusiforrne with high blood-anticoagulant activity should be sulfated polysaccharides, in which the activity was positively correlated with the content of total sugar and fucose in sulfated polysaccharides. As for Undaria pinnatifida, the n-butanol extract fractionated from the 80% ethanol soluble fraction had blood anticoagulant activity, while the petroleum ether, ether, ethyl acetate, or water extract showed no bloodanticoagulant activity.

  7. Recombinant human activated protein C inhibits local and systemic activation of coagulation without influencing inflammation during Pseudomonas aeruginosa pneumonia in rats

    NARCIS (Netherlands)

    Choi, Goda; Hofstra, Jorrit-Jan H; Roelofs, Joris J T H; Florquin, Sandrine; Bresser, Paul; Levi, Marcel; van der Poll, Tom; Schultz, Marcus J

    2007-01-01

    OBJECTIVE: Alveolar fibrin deposition is a hallmark of pneumonia. It has been proposed that recombinant human activated protein C exerts lung-protective effects via anticoagulant and anti-inflammatory pathways. We investigated the role of the protein C system in pneumonia caused by Pseudomonas aerug

  8. Regulation of human protein S gene (PROS1) transcription

    NARCIS (Netherlands)

    Wolf, Cornelia de

    2006-01-01

    This thesis describes the investigation of the transcriptional regulation of the gene for anticoagulant plasma Protein S, PROS1. Protein S is a cofactor for Protein C in the Protein C anticoagulant pathway. The coagulation cascade is negatively regulated by this pathway through inactivation of activ

  9. Endogenous activated protein C limits cancer cell extravasation through sphingosine-1-phosphate receptor 1-mediated vascular endothelial barrier enhancement

    NARCIS (Netherlands)

    G.L. van Sluis; T.M.H. Niers; C.T. Esmon; W. Tigchelaar; D.J. Richel; H.R. Buller; C.J.F. van Noorden; C.A. Spek

    2009-01-01

    Activated protein C (APC) has both anticoagulant activity and direct cell-signaling properties. APC has been reported to promote cancer cell migration/invasion and to inhibit apoptosis and therefore may exacerbate metastasis. Opposing these activities, APC signaling protects the vascular endothelial

  10. Venous Thromboembolism Anticoagulation Therapy

    Institute of Scientific and Technical Information of China (English)

    刘泽霖

    2009-01-01

    @@ VTE of the main treatment for anticoagulant thera-py, anticoagulant therapy drug of choice for low molecu-lar weight heparin (LMWH) for the overwhelming major-ity of clinicians agree that long-term oral anticoagulant therapy is still Vit. K antagonist (mainly warfarin).

  11. Impact of nonsynonymous mutations of factor X on the functions of factor X and anticoagulant activity of edoxaban.

    Science.gov (United States)

    Noguchi, Kengo; Morishima, Yoshiyuki; Takahashi, Shinichi; Ishihara, Hiroaki; Shibano, Toshiro; Murata, Mitsuru

    2015-03-01

    Edoxaban is an oral direct factor Xa (FXa) inhibitor and its efficacy as an oral anticoagulant is less subject to drug-food and drug-drug interaction than existing vitamin K antagonists. Although this profile of edoxaban suggests it is well suited for clinical use, it is not clear whether genetic variations of factor X influence the activity of edoxaban. Our aim was to investigate a possible impact of single-nucleotide polymorphisms (SNPs) in the factor X gene on the functions of factor X and the activity of edoxaban. Two nonsynonymous SNPs within mature factor X, Ala152Thr and Gly192Arg, were selected as possible candidates that might affect the functions of FXa and the activity of edoxaban. We measured catalytic activities of wild type and mutant FXas in a chromogenic assay using S-2222 and coagulation times including prothrombin time (PT) and activated partial thrombin time (aPTT) of plasma-containing recombinant FXs in the presence and absence of edoxaban. Michaelis-Menten kinetic parameters of FXas, Km and Vmax values, PT and aPTT were not influenced by either mutation indicating these mutations do not affect the FXa catalytic and coagulation activities. The Ki values of edoxaban for the FXas and the concentrations of edoxaban required to double PT and aPTT were not different between wild type and mutated FXas indicating that both mutations have little impact on the activity of edoxaban. In conclusion, these data suggest that edoxaban has little interpatient variability stemming from SNPs in the factor X gene. PMID:24911450

  12. Isolamento, fracionamento e atividade anticoagulante de iota-carragenanas da Solieria filiformis Isolation, fractionation and anticoagulant activity of iota-carrageenans from Solieria filiformis

    Directory of Open Access Journals (Sweden)

    José Ariévilo Gurgel Rodrigues

    2010-11-01

    Full Text Available Este estudo teve como objetivo isolar, fracionar e avaliar o potencial anticoagulante de iota-carragenanas (i-CARs da rodofícea Solieria filiformis, quando obtidas por dois métodos de extração (M I e M II. As i-CARs foram isoladas com papaína bruta em tampão acetato de sódio 0,1M (pH 5,0, contendo cisteína 5mM e EDTA 5mM (M I ou água (80°C (M II e, em seguida, determinada sua composição química de carboidratos totais, sulfato livre (SL e proteínas contaminantes. As i-CARs foram submetidas à cromatografia de troca iônica (DEAE-celulose usando um gradiente de cloreto de sódio, sendo avaliado o tempo de tromboplastina parcial ativada (TTPA e tempo de protrombina das frações obtidas e comparadas à heparina (193UI mg-1. Uma fração anticoagulante também foi submetida ao procedimento de eletroforese em gel de agarose a 0,5%. A diferença no rendimento de i-CARs entre os métodos foi 10,14%. A composição química de SL (29,40% e o fracionamento, por DEAE-celulose, indicaram o M I mais eficiente na obtenção de i-CARs, comparado ao M II. O TTPA também foi somente alterado para as i-CARs do M I. Contudo, a atividade anticoagulante in vitro de uma fração rica (8,52UI mg-1 foi inferior à da heparina.This study aimed to isolate, fractionate and evaluate the anticoagulant potential of iota-carrageenans (i-CARs from Solieria filiformis when two extraction methods (M I and M II were used. i-CARs were isolated with papain in 0.1M sodium acetate (pH 5.0 containing 5mM cystein and 5mM EDTA (M I or water (80°C (M II, and then their chemical composition of total carbohydrates, free sulfate (FS and contaminant proteins were determined. i-CARs were submitted to anion-exchange chromatography (DEAE-cellulose using a sodium chloride gradient,being evaluated the activated partial thromboplastin time (APTT and prothrombin time of obtained fractions and compared to heparin (193IU mg-1. A rich fraction of anticoagulant was also submitted to 0

  13. Protein C activation during the initial phase of experimental acute pancreatitis in the rabbit

    DEFF Research Database (Denmark)

    Ottesen, L H; Bladbjerg, E-M; Osman, M;

    2000-01-01

    activity), anticoagulant proteins (protein C, antithrombin) and fibrinolytic factors (tissue plasminogen activator, plasminogen activator inhibitor-1) were performed for 5 h. RESULTS: ANP was confirmed by elevated serum amylase, development of ascites, and histological changes of the pancreas. A moderate...... of the lungs or kidneys was found in 2 rabbits with ANP. CONCLUSION: An immediate activation of protein C is a specific characteristic of the haemostatic activation in ANP in rabbits. This activation has not been described previously and the possible therapeutic implications ought to be studied....

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

    DEFF Research Database (Denmark)

    Rangnekar, Abhijit; Zhang, Alex M.; Shiyuan Li, Susan;

    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...

  15. [Novel oral anticoagulants (NOAC)].

    Science.gov (United States)

    Ieko, Masahiro

    2015-10-01

    Novel oral anticoagulants (NOACs), a direct thrombin inhibitor (TDI), and direct factor Xa inhibitors (Xa-INHs) have mainly been used for prevention of stroke associated with atrial fibrillation in place of warfarin. DTI obstructs tenase by inhibiting thrombin generated in the initial phase and feedback to the amplification phase of cell-based coagulation reactions. Xa-INHs inhibit factor Xa activity in the prothrombinase complex of the propagation phase. Since the half-life of NOACs is in the approximate range of 8-14 hours, there are peak and trough periods in the blood concentrations of these agents. During the trough period, a small amount of thrombin is generated and plays a physiological role. The antithrombotic effect of NOACs is exerted during the peak period in combination with the effects of physiological coagulation inhibitors (PCIs) such as antithrombin in the trough period. Endothelial cells are the site for action of PCIs, such that it is important that they remain in a good state for effective anticoagulation by NOACs within the lesions. In a meta-analysis of NOACs vs. warfarin treatment, the former significantly reduced stroke or systemic embolic events by 19% as compared with warfarin, due mainly to a reduction in hemorrhagic stroke, while NOAC administration also significantly reduced intracranial hemorrhage by 52%. PMID:26458452

  16. Anticoagulation for Prosthetic Valves

    Directory of Open Access Journals (Sweden)

    Tsuyoshi Kaneko

    2013-01-01

    Full Text Available Implantation of prosthetic valve requires consideration for anticoagulation. The current guideline recommends warfarin on all mechanical valves. Dabigatran is the new generation anticoagulation medication which is taken orally and does not require frequent monitoring. This drug is approved for treatment for atrial fibrillation and venous thromboembolism, but the latest large trial showed that this drug increases adverse events when used for mechanical valve anticoagulation. On-X valve is the new generation mechanical valve which is considered to require less anticoagulation due to its flow dynamics. The latest study showed that lower anticoagulation level lowers the incidence of bleeding, while the risk of thromboembolism and thrombosis remained the same. Anticoagulation poses dilemma in cases such as pregnancy and major bleeding event. During pregnancy, warfarin can be continued throughout pregnancy and switched to heparin derivative during 6–12 weeks and >36 weeks of gestation. Warfarin can be safely started after 1-2 weeks of discontinuation following major bleeding episode.

  17. Rivaroxaban: A novel anticoagulant

    Directory of Open Access Journals (Sweden)

    Muzaffar Ali

    2010-01-01

    Full Text Available For more than 50 years, warfarin has single-handedly ruled the world of anti-coagulation without any competition, whatsoever! The anticoagulant was made available in 1940 and since then no other anti-coagulant has ever been able to match it in the clinical arena. But it looks like that the advances in the field of anti-coagulation, for the first time, have seriously started to erode its base. This review takes a look at rivaroxaban, a direct factor Xa inhibitor and one of the most foremost competitors of warfarin.

  18. Rivaroxaban: A novel anticoagulant

    OpenAIRE

    Muzaffar Ali; C.L. Nawal

    2010-01-01

    For more than 50 years, warfarin has single-handedly ruled the world of anti-coagulation without any competition, whatsoever! The anticoagulant was made available in 1940 and since then no other anti-coagulant has ever been able to match it in the clinical arena. But it looks like that the advances in the field of anti-coagulation, for the first time, have seriously started to erode its base. This review takes a look at rivaroxaban, a direct factor Xa inhibitor and one of the most foremost co...

  19. Acute coagulopathy of trauma: balancing progressive catecholamine induced endothelial activation and damage by fluid phase anticoagulation

    DEFF Research Database (Denmark)

    Johansson, P I; Ostrowski, S R

    2010-01-01

    Acute coagulopathy of trauma predicts a poor clinical outcome. Tissue trauma activates the sympathoadrenal system resulting in high circulating levels of catecholamines that influence hemostasis dose-dependently through immediate effects on the two major compartments of hemostasis, i.e., the...... circulating blood and the vascular endothelium. There appears to be a dose-dependency with regards to injury severity and the hemostatic response to trauma evaluated in whole blood by viscoelastic assays like thrombelastography (TEG), changing from normal to hypercoagulable, to hypocoagulable and finally...... evolutionary developed response that counterbalances the injury and catecholamine induced endothelial activation and damage. Given this, the rise in circulating catecholamines in trauma patients may favor a switch from hyper- to hypocoagulability in the blood to keep the progressively more procoagulant...

  20. Antimicrobial and anticoagulant activities of N-chlorotaurine, N,N-dichloro-2,2-dimethyltaurine, and N-monochloro-2,2-dimethyltaurine in human blood.

    Science.gov (United States)

    Martini, C; Hammerer-Lercher, A; Zuck, M; Jekle, A; Debabov, D; Anderson, M; Nagl, M

    2012-04-01

    The aim of this study was to determine the potential application of N-chlorotaurine (NCT), N,N-dichloro-2,2-dimethyltaurine (NVC-422), and N-monochloro-2,2-dimethyltaurine (NVC-612) as catheter lock solutions for the prevention of catheter blockage and catheter-related bloodstream infections by testing their anticoagulant and broad-spectrum antimicrobial activities in human blood. NCT, NVC-422, NVC-612, and control compounds were serially diluted in fresh human blood to evaluate the effects on prothrombin time, activated partial thromboplastin time, thrombin time, fibrinogen, and direct thrombin inhibition. Quantitative killing assays against pathogens, including methicillin-resistant Staphylococcus aureus, Escherichia coli, and Candida albicans, were performed in the presence of heparin and human blood. NCT and NVC-612 (1.38 mM each) and 1.02 mM NVC-422 prolonged prothrombin time (Quick value, 17 to 30%), activated partial thromboplastin time 3- to 4-fold to 76 to 125 s, and thrombin time 2- to 4-fold to 34 to 68 s. Fibrinogen decreased from 258 to 283 mg/dl (range of controls) to Heparin did not influence the bactericidal activity of NCT. The microbicidal activities of NCT, NVC-422, and NVC-612 were maintained in diluted human blood. NCT, NVC-612, and NVC-422 have broad-spectrum antimicrobial activity in blood and anticoagulant activity targeting both intrinsic and extrinsic pathways of the coagulation system. These properties support their application as catheter lock solutions. PMID:22252818

  1. 桂郁金多糖抗凝血及纤溶活性研究%Anticoagulant and Fibrinolytic Activities of Polysaccharides from Curcuma kwangsiensis

    Institute of Scientific and Technical Information of China (English)

    潘小姣; 杨秀芬; 陈丽萍; 唐璐

    2013-01-01

    目的 研究桂郁金多糖体内抗凝血作用和含药血清体外纤溶活性.方法小鼠连续3 d灌胃给予高、中、低剂量桂郁金多糖,分别检测全凝血时间(CT)、凝血因子Ⅱ(PT)、活化部分凝血活酶时间(APTT)、凝血酶时间(TT)和凝血因子Ⅰ(Fbg),并将含药血清用纤维蛋白平板法进行体外纤溶试验.结果 桂郁金多糖能明显延长CT、APTT和TT(P<0.05),对PT和Fbg无明显影响;含药血清体外无纤溶活性.结论 桂郁金多糖具有显著的体内抗凝血活性,该药通过内源性凝血途径和共同凝血途径发挥抗凝血作用.%Objective To study anticoagulant and fibrinolytir activities of polysaccharides from Curcuma kwangsiensis. Methods The mice were administered by gavage with low, medium and high concentrations of polysaccharides for 3 days. Clotting time (CT) , prothrombin time (PT) , activated partial thromboplast in time (APTT) , thrombin time (TT) and fibrinogen (Fbg) of mice were detected. Fibrin plate method was performed to determine the fibrinolytir artiviy of medicated serum in vitro. Results The CT, APTT and TT were prolonged significantly (P<0.05) , but the PT and Fbg did not change. Conclusion The polysaccharides from Curcuma kwangsiensis have anticoagulant activities and exeit their anticoagulant activities through intrinsic pathway and common pathway oi coagulation.

  2. Erythrocyte-derived microparticles supporting activated protein C-mediated regulation of blood coagulation.

    Directory of Open Access Journals (Sweden)

    Ruzica Livaja Koshiar

    Full Text Available Elevated levels of erythrocyte-derived microparticles are present in the circulation in medical conditions affecting the red blood cells. Erythrocyte-derived microparticles expose phosphatidylserine thus providing a suitable surface for procoagulant reactions leading to thrombin formation via the tenase and prothrombinase complexes. Patients with elevated levels of circulating erythrocyte-derived microparticles have increased thrombin generation in vivo. The aim of the present study was to investigate whether erythrocyte-derived microparticles are able to support the anticoagulant reactions of the protein C system. Erythrocyte-derived microparticles were isolated using ultracentrifugation after incubation of freshly prepared erythrocytes with the ionophore A23187 or from outdated erythrocyte concentrates, the different microparticles preparations yielding similar results. According to flow cytometry analysis, the microparticles exposed phoshatidylserine and bound lactadherin, annexin V, and protein S, which is a cofactor to activated protein C. The microparticles were able to assemble the tenase and prothrombinase complexes and to stimulate the formation of thrombin in plasma-based thrombin generation assay both in presence and absence of added tissue factor. The addition of activated protein C in the thrombin generation assay inhibited thrombin generation in a dose-dependent fashion. The anticoagulant effect of activated protein C in the thrombin generation assay was inhibited by a monoclonal antibody that prevents binding of protein S to microparticles and also attenuated by anti-TFPI antibodies. In the presence of erythrocyte-derived microparticles, activated protein C inhibited tenase and prothrombinase by degrading the cofactors FVIIIa and FVa, respectively. Protein S stimulated the Arg306-cleavage in FVa, whereas efficient inhibition of FVIIIa depended on the synergistic cofactor activity of protein S and FV. In summary, the erythrocyte

  3. Anticoagulant modulation of inflammation in severe sepsis.

    Science.gov (United States)

    Allen, Karen S; Sawheny, Eva; Kinasewitz, Gary T

    2015-05-01

    Inflammation and coagulation are so tightly linked that the cytokine storm which accompanies the development of sepsis initiates thrombin activation and the development of an intravascular coagulopathy. This review examines the interaction between the inflammatory and coagulation cascades, as well as the role of endogenous anticoagulants in regulating this interaction and dampening the activity of both pathways. Clinical trials attempting to improve outcomes in patients with severe sepsis by inhibiting thrombin generation with heparin and or endogenous anticoagulants are reviewed. In general, these trials have failed to demonstrate that anticoagulant therapy is associated with improvement in mortality or morbidity. While it is possible that selective patients who are severely ill with a high expected mortality may be shown to benefit from such therapy, at the present time none of these anticoagulants are neither approved nor can they be recommended for the treatment of sepsis. PMID:25938026

  4. Optical profiling of anticoagulation status (Conference Presentation)

    Science.gov (United States)

    Tshikudi, Diane M.; Tripathi, Markandey M.; Hajjarian, Zeinab; Nadkarni, Seemantini K.

    2016-02-01

    Defective blood coagulation resulting from excessive procoagulant activity often leads to thrombotic disorders such as stroke and myocardial infarction. A variety of oral and injectable anticoagulant drugs are prescribed to prevent or treat life-threatening thrombosis. However, due to bleeding complications often associated with anticoagulant treatment, routine monitoring and accurate dosing of anticoagulant therapy is imperative. We have developed Optical thromboelastography (OTEG), a non-contact approach that utilizes a drop of whole blood to measure blood coagulation status in patients. Here, we demonstrate the capability of OTEG for rapidly monitoring anticoagulation in whole blood samples. OTEG monitors coagulation status by assessing changes in blood viscosity from temporal intensity fluctuations of laser speckle patterns during clotting. In OTEG a blood drop is illuminated with coherent light and the blood viscosity is measured from the speckle intensity autocorrelation curve, g2 (t). The metrics, clotting time (R+k), clot progression (angle) and maximum clot stiffness (MA) are then extracted. The aim of the current study was to evaluate the accuracy of OTEG in assessing anticoagulation status of common anticoagulants including heparin, argatroban and rivaroxaban status. A dose-dependent prolongation of R+k was observed in anticoagulated blood, which closely corresponded with standard-reference Thromboelastography (TEG) (r 0.87-0.99, P>0.01 for all cases). OTEG angle was unaltered by anticoagulation whereas TEG angle presented a dose-dependent diminution probably linked to clot rupture. In both OTEG and TEG, MA was unaffected by heparin, argatroban or rivaroxaban. We conclude that OTEG can accurately monitor anticoagulation status following treatment, potentially providing a powerful tool for routine monitoring of patients in the doctor's office or in the home setting.

  5. Activated protein C to heal pressure ulcers.

    Science.gov (United States)

    Wijewardena, Aruna; Lajevardi, Sepehr S; Vandervord, Elle; Vandervord, John; Lang, Thomas C; Fulcher, Gregory; Jackson, Christopher J

    2016-10-01

    Pressure ulcers present a major clinical challenge, are physically debilitating and place the patient at risk of serious comorbidities such as septic shock. Recombinant human activated protein C (APC) is an anticoagulant with anti-inflammatory, cytoprotective and angiogenic effects that promote rapid wound healing. Topical negative pressure wound therapy (TNP) has become widely used as a treatment modality in wounds although its efficacy has not been proven through randomised controlled trials. The aim of this study was to determine the preliminary efficacy and safety of treatment with APC for severe chronic pressure sores with and without TNP. This case presentation describes the history, management and outcome of two patients each with a severe chronic non-healing pressure ulcer that had failed to respond to conventional therapy. TNP was added to conservative management of both ulcers with no improvement seen. Then local application of small doses of APC was added to TNP and with conservative management, resulted in significant clinical improvement and rapid healing of both ulcers, displaying rapid growth of vascular granulation tissue with subsequent epithelialisation. Patients tolerated the treatment well and improvements suggested by long-term follow-up were provided. Randomised placebo-controlled double blind trials are needed to quantify the efficacy, safety, cost-effectiveness, optimal dose and quality of life changes seen from treatment with APC.

  6. Anticoagulation control in atrial fibrillation patients present to outpatient clinic of cardiology versus anticoagulant clinics

    Institute of Scientific and Technical Information of China (English)

    DU Xin; MA Chang-sheng; LIU Xiao-hui; DONG Jian-zeng; WANG Jun-nan; CHENG Xiao-jing

    2005-01-01

    @@ Nonvalvular atrial fibrillation (NVAF) is the most common sustained cardiac arrhythmia in clinical practice, which if untreated results in a doubling of cardiovascular morbidity and mortality. AF is an independent predictor of stroke, with an annual risk 5 to 6 times higher than patients in sinus rhythm.1 During recent years, several randomised clinical trials conducted by investigators around the world involving 13 843 participants with NVAF have demonstrated convincingly the value of warfarin therapies for stroke prevention in high risk patients.2-8 However, the dose response of warfarin is complex and its activity is easily altered by concurrent medications, food interactions, alcohol and illnesses. Adherence to medical advice and routine monitoring of the international normalized ratio (INR) is important, because low anticoagulant intensity predisposes the patients to thromboembolic complications and high intensity to haemorrhage. Studies suggested that anticoagulant clinics could improve the quality of anticoagulation control,9 and anticoagulant clinics are common in western countries. However, in China, most AF patients taking warfarin usually attend the outpatient clinic of cardiology, while the quality of anticoagulation control is never investigated. We therefore assessed anticoagulation control in the outpatient clinic of cardiology, and the quality of anticoagulation control since the establishment of anticoagulant clinics.

  7. Coagulation factor V mediates inhibition of tissue factor signaling by activated protein C in mice.

    Science.gov (United States)

    Liang, Hai Po H; Kerschen, Edward J; Basu, Sreemanti; Hernandez, Irene; Zogg, Mark; Jia, Shuang; Hessner, Martin J; Toso, Raffaella; Rezaie, Alireza R; Fernández, José A; Camire, Rodney M; Ruf, Wolfram; Griffin, John H; Weiler, Hartmut

    2015-11-19

    The key effector molecule of the natural protein C pathway, activated protein C (aPC), exerts pleiotropic effects on coagulation, fibrinolysis, and inflammation. Coagulation-independent cell signaling by aPC appears to be the predominant mechanism underlying its highly reproducible therapeutic efficacy in most animal models of injury and infection. In this study, using a mouse model of Staphylococcus aureus sepsis, we demonstrate marked disease stage-specific effects of the anticoagulant and cell signaling functions of aPC. aPC resistance of factor (f)V due to the R506Q Leiden mutation protected against detrimental anticoagulant effects of aPC therapy but also abrogated the anti-inflammatory and mortality-reducing effects of the signaling-selective 5A-aPC variant that has minimal anticoagulant function. We found that procofactor V (cleaved by aPC at R506) and protein S were necessary cofactors for the aPC-mediated inhibition of inflammatory tissue-factor signaling. The anti-inflammatory cofactor function of fV involved the same structural features that govern its cofactor function for the anticoagulant effects of aPC, yet its anti-inflammatory activities did not involve proteolysis of activated coagulation factors Va and VIIIa. These findings reveal a novel biological function and mechanism of the protein C pathway in which protein S and the aPC-cleaved form of fV are cofactors for anti-inflammatory cell signaling by aPC in the context of endotoxemia and infection.

  8. In Vivo Anticoagulant and Thrombolytic Activities of a Fibrinolytic Serine Protease (Brevithrombolase) With the k-Carrageenan-Induced Rat Tail Thrombosis Model.

    Science.gov (United States)

    Majumdar, Sourav; Chattopadhyay, Pronobesh; Mukherjee, Ashis K

    2016-09-01

    In the present study, in vivo thrombolysis efficiency of Brevithrombolase, a nontoxic fibrinolytic enzyme purified from Brevibacillus brevis strain FF02B, was affirmed by significant inhibition of thrombus formation in the k-carrageenan-induced rat tail, in a dose-dependent manner. Brevithrombolase at a dose of 600 µg/kg showed an efficacy that was comparable to streptokinase and plasmin, in dissolving in vivo thrombus of k-carrageenan-treated rats under identical conditions. The in vivo anticoagulant property of Brevithrombolase was demonstrated by its prolongation of activated partial thromboplastin time, prothrombin time, and thrombin time in Wistar rats. However, the Brevithrombolase-treated rats demonstrated an insignificant decrease in fibrinogen (Fg) level of plasma compared with Fg level of control group of rats corroborating in vivo as well as in vitro anticoagulant activity of Brevithrombolase is due to its hydrolytic action on thrombin. These findings unequivocally suggest that Brevithrombolase may serve a promising alternative to the commercial thrombolytic drugs. PMID:25657326

  9. Detailed Mechanisms of the Inactivation of Factor VIIIa by Activated Protein C in the Presence of Its Cofactors, Protein S and Factor V*

    OpenAIRE

    Gale, Andrew J.; Cramer, Thomas J.; Rozenshteyn, Diana; Cruz, Jason R.

    2008-01-01

    Factor VIIIa is inactivated by a combination of two mechanisms. Activation of factor VIII by thrombin results in a heterotrimeric factor VIIIa that spontaneously inactivates due to dissociation of the A2 subunit. Additionally, factor VIIIa is cleaved by the anticoagulant serine protease, activated protein C, at two cleavage sites, Arg336 in the A1 subunit and Arg562 in the A2 subunit. We previously characterized an engineered variant of factor VIII which contains a dis...

  10. Partial Purification and Characterization of Anticoagulant Factor from the Snake (Echis carinatus Venom

    Directory of Open Access Journals (Sweden)

    Elham Amrollahi Byoki

    2013-11-01

    Full Text Available   Objective(s: Snake venoms contain complex mixture of proteins with biological activities. Some of these proteins affect blood coagulation and platelet function in different ways. Snake venom toxin may serve as a starting material for drug design to combat several pathophysiological problems such as cardiovascular disorders. In the present study, purification of anticoagulation factor from venom of snake (Echis carinatus was studied. Anticoagulation activity of crude venom, fractions and purified peptide were determined by using prothrombin time (PT and thrombin time (TT. Three fractions were partially purified from the venom of E. Carinatus by gel filtration on sephadex G-75 and final purification was performed by high-performance liquid chromatography (HPLC with C18 column. A purified anticoagulant factor was derived which showed a single protein band in SDS-PAGE electrophoresis under reducing condition. Results of PT and TT tests for purified peptide (EC217 were found to be 102±4.242 and < 5 min. respectively. Determination of molecular weight revealed that the active purified peptide (EC217 was about 30 KD. In conclusion, the present study showed that the venom of E. carinatus contains at least one anticoagulant factor.

  11. The predictability of bleeding by prothrombin times sensitive or insensitive to PIVKA during intensive oral anticoagulation.

    Science.gov (United States)

    Arnesen, H; Smith, P

    1991-02-01

    To evaluate the effect of PIVKA (Proteins Induced by Vitamin K Absence or Antagonism) on the bleeding tendency during oral anticoagulation, we studied consecutive patients intensively treated with warfarin (INR greater than 4.8). The level of anticoagulation was measured with the PIVKA-insensitive Normotest (NT) as well as with the PIVKA-sensitive Thrombotest (TT), and the results are expressed as per cent coagulant activity. The NT/TT ratio was determined. Twenty patients with bleeding episodes had a mean NT/TT ratio of 2.06 as compared to 2.20 in 143 patients without bleeding episodes (p = 0.08). As the NT/TT ratio was not higher in patients with bleedings, we conclude that PIVKA are of no importance for bleeding during anticoagulation with vitamin K antagonists.

  12. Secretion of a proteolytic anticoagulant by Ancylostoma hookworms

    OpenAIRE

    1983-01-01

    Hookworms of the genus Ancylostoma secrete an anticoagulant that both inhibits the clotting of human plasma and promotes fibrin clot dissolution. This anticoagulant activity is attributable to a 36,000 dalton proteolytic enzyme. The protease can degrade fibrinogen into five smaller polypeptides that intrinsically have anticoagulating properties, covert plasminogen to a mini-plasminogen-like molecule, and hydrolyze a synthetic peptide substrate with specificity for elastolytic enzymes. It is h...

  13. Anticoagulation for pediatric mechanical circulatory support.

    Science.gov (United States)

    Annich, Gail; Adachi, Iki

    2013-06-01

    Extracorporeal life support applications have evolved considerably in recent years. However, the blood-biomaterial interface remains incompletely understood, and management of the acute inflammatory response and coagulation pathways continues to be challenging. At present, the gold standard for anticoagulation is unfractionated heparin. Since the inception of extracorporeal life support, the mainstay for anticoagulation monitoring has been activated clotting time. However, alongside the technological evolution in extracorporeal life support, the methods for monitoring heparin have also become more sophisticated, adding additional layers of complexity to creating an ideal safe protocol for anticoagulation during extracorporeal life support. To address this, the Extracorporeal Life Support Organization has formed an Anticoagulation Task Force to help direct both a consensus statement and potential guidelines within which the multiple monitoring methods can be customized for extracorporeal life support. One key question that remains in the use of these monitoring methods is whether the objective during extracorporeal life support is to anticoagulate the circuit to prevent thrombus formation within the extracorporeal device or whether it is to systemically anticoagulate the patient. This review details all current monitoring methods and highlights how they can be used during pediatric mechanical circulatory support. PMID:23735984

  14. Changing trends in anti-coagulant therapies. Are heparins and oral anti-coagulants challenged?

    Science.gov (United States)

    Fareed, J; Iqbal, O; Cunanan, J; Demir, M; Wahi, R; Clarke, M; Adiguzel, C; Bick, R

    2008-06-01

    The conventional management of thrombotic and cardiovascular disorders is based on the use of heparin, oral anticoagulants and aspirin. Despite progress in the sciences, these drugs still remain a challenge and mystery. The development of low molecular weight heparins (LMWHS) and the synthesis of heparinomimetics represent a refined use of heparin. Additional drugs will continue to develop. However, none of these drugs will ever match the polypharmacology of heparin. Aspirin still remains the leading drug in the management of thrombotic and cardiovascular disorders. The newer antiplatelet drugs such as adenosine diphosphate receptor inhibitors, GPIIb/IIIa inhibitors and other specific inhibitors have limited effects and have been tested in patients who have already been treated with aspirin. Warfarin provides a convenient and affordable approach in the long-term outpatient management of thrombotic disorders. The optimized use of these drugs still remains the approach of choice to manage thrombotic disorders. The new anticoagulant targets, such as tissue factor, individual clotting factors, recombinant forms of serpins (antithrombin, heparin co-factor II and tissue factor pathway inhibitors), recombinant activated protein C, thrombomodulin and site specific serine proteases inhibitors complexes have also been developed. There is a major thrust on the development of orally bioavailable anti-Xa and IIa agents, which are slated to replace oral anticoagulants. Both the anti-factor Xa and anti-IIa agents have been developed for oral use and have provided impressive clinical results. However, safety concerns related to liver enzyme elevations and thrombosis rebound have been reported with their use. For these reasons, the US Food and Drug Administration did not approve the orally active antithrombin agent Ximelagatran for several indications. The synthetic pentasaccharide (Fondaparinux) has undergone clinical development. Unexpectedly, Fondaparinux also produced major

  15. Review of Urgent Reversal Therapies for Oral Anticoagulation

    Directory of Open Access Journals (Sweden)

    John J. Mondin II

    2016-09-01

    Full Text Available Anticoagulation has proven to be one of the most essential breakthroughs in cardiology in the last 100 years. The first major oral anticoagulant, warfarin, is a 4-hydroxycourmarin first synthesized in the 1940s for use as a rodenticide. It was not until 1954 that warfarin was finally approved by the FDA for use in patients requiring systemic anticoagulation. For over 55 years, warfarin was the only oral anticoagulant available in the United States until the approval of dabigatran in 2010, ushering in the era of the direct oral anticoagulants. This article will review modalities of anticoagulation reversal including activated charcoal, hemodialysis, blood-derived products, and medications currently available as well as in development.

  16. Separating proteins with activated carbon.

    Science.gov (United States)

    Stone, Matthew T; Kozlov, Mikhail

    2014-07-15

    Activated carbon is applied to separate proteins based on differences in their size and effective charge. Three guidelines are suggested for the efficient separation of proteins with activated carbon. (1) Activated carbon can be used to efficiently remove smaller proteinaceous impurities from larger proteins. (2) Smaller proteinaceous impurities are most efficiently removed at a solution pH close to the impurity's isoelectric point, where they have a minimal effective charge. (3) The most efficient recovery of a small protein from activated carbon occurs at a solution pH further away from the protein's isoelectric point, where it is strongly charged. Studies measuring the binding capacities of individual polymers and proteins were used to develop these three guidelines, and they were then applied to the separation of several different protein mixtures. The ability of activated carbon to separate proteins was demonstrated to be broadly applicable with three different types of activated carbon by both static treatment and by flowing through a packed column of activated carbon. PMID:24898563

  17. Separating proteins with activated carbon.

    Science.gov (United States)

    Stone, Matthew T; Kozlov, Mikhail

    2014-07-15

    Activated carbon is applied to separate proteins based on differences in their size and effective charge. Three guidelines are suggested for the efficient separation of proteins with activated carbon. (1) Activated carbon can be used to efficiently remove smaller proteinaceous impurities from larger proteins. (2) Smaller proteinaceous impurities are most efficiently removed at a solution pH close to the impurity's isoelectric point, where they have a minimal effective charge. (3) The most efficient recovery of a small protein from activated carbon occurs at a solution pH further away from the protein's isoelectric point, where it is strongly charged. Studies measuring the binding capacities of individual polymers and proteins were used to develop these three guidelines, and they were then applied to the separation of several different protein mixtures. The ability of activated carbon to separate proteins was demonstrated to be broadly applicable with three different types of activated carbon by both static treatment and by flowing through a packed column of activated carbon.

  18. Patient values and preferences when choosing anticoagulants

    Directory of Open Access Journals (Sweden)

    Palacio AM

    2015-01-01

    unexposed to anticoagulants reported that they would select a medication that has an antidote even if the risk of bleeding was very small. Twenty-three percent of the unexposed and 22% of the exposed groups reported that they would prefer the medication that gives the best quality of life.Conclusion: Our study found that patients who may be exposed to an anticoagulation decision prefer to actively participate in the decision-making process, and have individual values for making a decision that cannot be predicted or assumed by anyone in the health care system. Keywords: warfarin, oral anticoagulant, bleeding risk, atrial fibrillation, patient decision making, medication selection

  19. Anticoagulant activity of sulfated polysaccharides fractions from an aqueous extract obtained from the red seaweed Halymenia floresia (Clemente C. Agardh - doi: 10.4025/actascitechnol.v33i4.9143

    Directory of Open Access Journals (Sweden)

    José Ariévilo Gurgel Rodrigues

    2011-09-01

    Full Text Available Heparin (HEP is known due to their side effects and the red seaweed Halymenia floresia (Hf sulfated polysaccharides (SP are heparinoids. In this study we purified the Hf-SP obtained from an aqueous extract and evaluated their anticoagulant activities. Hf-SP1 (25°C, Hf-SP2 (80°C and Hf-SP3 (80°C were sequentially isolated. Hf-SP3 had the highest sulfate content (37.45%. Hf-SP3 was fractionated by ion exchange chromatography on a DEAE-cellulose column using a NaCl gradient. Fractions were lyophilized and submitted to 0.5% agarose gel electrophoresis. The anticoagulant activity was evaluated by the activated partial thromboplastin time using rabbits plasma and expressed in international units per mg of SP using standard HEP (193 IU mg-1. The chromatographic procedure separated into four different SP fractions (F I, F II, F III and F IV eluted at concentrations of 0.50, 0.75, 1.00 and 1.25 M of NaCl, respectively, reveling among them different marked on charge density, when compared by electrophoresis. F III had the highest anticoagulant activity (10.72 IU mg-1, suggesting that the sulfate is important in this process. In conclusion, our results suggest that sequential extractions of Hf-SP are an important biotechnological tool for identification of novel anticoagulants and studies of structural characterization are already in progress.

  20. Lupus anticoagulants and antiphospholipid antibodies

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/000547.htm Lupus anticoagulants and antiphospholipid antibodies To use the sharing features on this page, please enable JavaScript. Lupus anticoagulants are antibodies against substances in the lining ...

  1. Anticoagulant therapy for sepsis-associated disseminated intravascular coagulation: the view from Japan.

    Science.gov (United States)

    Iba, T; Gando, S; Thachil, J

    2014-07-01

    The current management of disseminated intravascular coagulation (DIC) is based on aggressive treatment of the underlying condition and resuscitation with appropriate blood products. Anticoagulant therapy has appeared and disappeared in the different guidelines and important documents detailing the treatment of DIC. For example, Surviving Sepsis Campaign (SSC) guidelines, the 'global standard' for the management of severe sepsis, had recombinant activated protein C highly recommended in the original version, but this was withdrawn in the latest version due to the lack of evidence. In contrast, recent international guidance released from the International Society on Thrombosis and Haemostasis has introduced the potential efficacy of other agents. In sepsis-related DIC, the basis for anticoagulant therapy comes from the mounting evidence for the anti-inflammatory effects which these agents possess and can prove beneficial in septic situations. Several studies have clearly shown the important cross-talk between coagulation and inflammation in patients with sepsis. More recently, neutrophil extracellular traps and damage-associated molecular patterns (DAMPs), especially histones, have been demonstrated to play a crucial role in the coagulopathy of sepsis. Once again, the natural anticoagulants have an important function in neutralizing the effects of DAMPs and histones. In this review, in addition to examining the important role of anticoagulants in the septic milieu, the clinical studies examining antithrombin, recombinant thrombomodulin and plasma-derived activated protein C are detailed. However, large-scale randomized controlled trials are yet to be performed, with important consideration of the timing, dosage and duration of treatment.

  2. The in-vitro anticoagulant effect of rivaroxaban in neonates.

    Science.gov (United States)

    Attard, Chantal; Monagle, Paul; Kubitza, Dagmar; Ignjatovic, Vera

    2014-04-01

    The use of anticoagulants in neonates is increasing because of the medical advances improving the long-term survival of very sick infants who are at risk of venous thromboembolism (VTE). Current anticoagulation therapy in neonates is less than ideal, because of the physiological differences compared to children and adults regarding the pathophysiology of thrombosis and pharmacology of the drug. Limitations associated with conventional anticoagulants have prompted the development of novel drugs that specifically target the key proteins in the coagulation system. Rivaroxaban is the first oral, direct Factor Xa inhibitor available for the prevention of VTE in adults. Its predictable pharmacokinetic profile, high oral bioavailability and once-daily dosing make rivaroxaban an optimal anticoagulant that warrants investigation in neonates. This study was designed to determine whether there are age-related differences in the pharmacodynamic effects of rivaroxaban in vitro amongst neonates. Neonatal and adult plasma pools were created and spiked with increasing concentrations of rivaroxaban (0-500 ng/ml). Commercially available prothrombin time (PT), activated partial thromboplastin time (aPTT) and anti-Factor Xa assays as well as a sub-sampling thrombin generation assay were used to measure the rivaroxaban effect. A dose-dependent response was observed for PT, aPTT and lag time in both the age groups. Rivaroxaban caused a significant increase in the clotting time for PT and aPTT as well as an increase in lag time (as measured by thrombin generation) in neonates when compared with adults. In-vivo studies are required to confirm the consistency of dose-response in neonates. PMID:24418940

  3. Anticoagulation management during cross-clamping and bypass.

    Science.gov (United States)

    Lander, H; Zammert, M; FitzGerald, D

    2016-09-01

    Anticoagulation is required for successful implementation of cardiopulmonary bypass (CPB), as well as for surgeries requiring temporary aortic occlusion. It is well established that both coagulation and fibrinolysis are activated during CPB (Teufelsbauer et al., 1992) [1]. Appropriate dosing, monitoring, and maintenance of anticoagulation are essential to prevent devastating thrombosis of the CPB circuit or the occluded aorta and to minimize the activation of the hemostatic system. Although numerous novel anticoagulants have been developed over the past decade, unfractionated heparin remains the primary anticoagulant utilized during these types of procedures, with monitoring systems primarily based upon the activated clotting time and/or heparin concentration. This article will review the current state of anticoagulation management during cross-clamp and CPB. PMID:27650345

  4. Neuroprotective effects of activated protein C on intrauterine inflammation-induced neonatal white matter injury are associated with the downregulation of fibrinogen-like protein 2/fibroleukin prothrombinase and the inhibition of pro-inflammatory cytokine expression

    OpenAIRE

    JIN, SHENG-JUAN; Yan LIU; DENG, SHI-HUA; LIAO, LI-HONG; LIN, TU-LIAN; Ning, Qin; LUO, XIAO-PING

    2015-01-01

    Maternal intrauterine inflammation or infection is an important risk factor for neonatal cerebral white matter injury (WMI) and future neurological deficits. Activated protein C (APC), a natural anticoagulant, has been shown to exhibit anti-inflammatory, anti-apoptotic, profibrinolytic and cytoprotective activities. Recent studies have demonstrated that the novel prothrombinase, fibrinogen-like protein 2 (fgl2), contributes to the pathogenesis of a number of inflammatory diseases through the ...

  5. Cataract surgery and anticoagulants

    NARCIS (Netherlands)

    Koopmans, SA; VanRij, G

    1996-01-01

    A questionnaire was sent to 240 members of the Netherlands Intraocular implant Club (NIOIC) to register their policy followed in 1993 with regard to anticoagulant therapy (ACT) and the use of aspirin in patients having cataract surgery. Ninety-one (32%) forms were suitable for analysis. Most eye sur

  6. Anticoagulation in atrial fibrillation.

    Science.gov (United States)

    Steinberg, Benjamin A; Piccini, Jonathan P

    2014-01-01

    Atrial fibrillation increases the risk of stroke, which is a leading cause of death and disability worldwide. The use of oral anticoagulation in patients with atrial fibrillation at moderate or high risk of stroke, estimated by established criteria, improves outcomes. However, to ensure that the benefits exceed the risks of bleeding, appropriate patient selection is essential. Vitamin K antagonism has been the mainstay of treatment; however, newer drugs with novel mechanisms are also available. These novel oral anticoagulants (direct thrombin inhibitors and factor Xa inhibitors) obviate many of warfarin's shortcomings, and they have demonstrated safety and efficacy in large randomized trials of patients with non-valvular atrial fibrillation. However, the management of patients taking warfarin or novel agents remains a clinical challenge. There are several important considerations when selecting anticoagulant therapy for patients with atrial fibrillation. This review will discuss the rationale for anticoagulation in patients with atrial fibrillation; risk stratification for treatment; available agents; the appropriate implementation of these agents; and additional, specific clinical considerations for treatment. PMID:24733535

  7. [Anticoagulation in patients with chronic renal failure].

    Science.gov (United States)

    Niksic, L; Saudan, P; Boehlen, F

    2006-03-01

    Anticoagulation may be difficult to implement in patients suffering from chronic renal failure on account of platelet disorders and impaired clearance of some anticoagulant drugs. Although no adjustment of heparin and coumarin dosage is necessary, more frequent testing of coagulation pathways may be required when these drugs are used in patients with renal failure. Long-term use of LMWH should be implemented cautiously with regular testing of anti-factor Xa activity and a half-dose may be advocated in patients with a creatinine clearance heparin-induced thrombocytopenia with regular monitoring of coagulation tests. PMID:16562602

  8. Activated protein C: A regulator of human skin epidermal keratinocyte function

    Institute of Scientific and Technical Information of China (English)

    Kelly; McKelvey; Christopher; John; Jackson; Meilang; Xue

    2014-01-01

    Activated protein C(APC) is a physiological anticoagulant, derived from its precursor protein C(PC). Independent of its anticoagulation, APC possesses strong anti-inflammatory, anti-apoptotic and barrier protective properties which appear to be protective in a number of disorders including chronic wound healing. The epidermis is the outermost skin layer and provides the first line of defence against the external environment. Keratinocytes are the most predominant cells in the epidermis and play a critical role in maintaining epidermal barrier function. PC/APC and its receptor, endothelial protein C receptor(EPCR), once thought to be restricted to the endothelium, are abundantly expressed by skin epidermal keratinocytes. These cells respond to APC by upregulating proliferation, migration and matrix metalloproteinase-2 activity and inhibiting apoptosis/inflammation leading to a wound healing phenotype. APC also increases barrier function of keratinocyte monolayers by promoting the expression of tight junction proteins and re-distributing them to cell-cell contacts. These cytoprotective properties of APC are mediated through EPCR, protease-activated receptors, epidermal growth factor receptor or Tie2. Future preventive and therapeutic uses of APC in skin disorders associated with disruption of barrier function and inflammation look promising. This review will focus on APC’s function in skin epidermis/keratinocytes and its therapeutical potential in skin inflammatory conditions.

  9. Activated protein C: A regulator of human skin epidermal keratinocyte function.

    Science.gov (United States)

    McKelvey, Kelly; Jackson, Christopher John; Xue, Meilang

    2014-05-26

    Activated protein C (APC) is a physiological anticoagulant, derived from its precursor protein C (PC). Independent of its anticoagulation, APC possesses strong anti-inflammatory, anti-apoptotic and barrier protective properties which appear to be protective in a number of disorders including chronic wound healing. The epidermis is the outermost skin layer and provides the first line of defence against the external environment. Keratinocytes are the most predominant cells in the epidermis and play a critical role in maintaining epidermal barrier function. PC/APC and its receptor, endothelial protein C receptor (EPCR), once thought to be restricted to the endothelium, are abundantly expressed by skin epidermal keratinocytes. These cells respond to APC by upregulating proliferation, migration and matrix metalloproteinase-2 activity and inhibiting apoptosis/inflammation leading to a wound healing phenotype. APC also increases barrier function of keratinocyte monolayers by promoting the expression of tight junction proteins and re-distributing them to cell-cell contacts. These cytoprotective properties of APC are mediated through EPCR, protease-activated receptors, epidermal growth factor receptor or Tie2. Future preventive and therapeutic uses of APC in skin disorders associated with disruption of barrier function and inflammation look promising. This review will focus on APC's function in skin epidermis/keratinocytes and its therapeutical potential in skin inflammatory conditions.

  10. Anticoagulation in Atrial Fibrillation

    OpenAIRE

    Ahmad, Yousif; YH Lip, Gregory

    2012-01-01

    Patients with atrial fibrillation (AF) are at increased thromboembolic risk, and they suffer more severe strokes with worse outcomes. Most thromboembolic complications of AF are eminently preventable with oral anticoagulation, and the increasing numbers of AF patients mean antithrombotic therapy is the most crucial management aspect of this common arrhythmia. Despite the proven efficacy of warfarin, a string of limitations have meant that it is underused by physicians and patients alike. This...

  11. Anticoagulation in atrial fibrillation

    OpenAIRE

    Steinberg, Benjamin A; Piccini, Jonathan P.

    2014-01-01

    Atrial fibrillation increases the risk of stroke, which is a leading cause of death and disability worldwide. The use of oral anticoagulation in patients with atrial fibrillation at moderate or high risk of stroke, estimated by established criteria, improves outcomes. However, to ensure that the benefits exceed the risks of bleeding, appropriate patient selection is essential. Vitamin K antagonism has been the mainstay of treatment; however, newer drugs with novel mechanisms are also availabl...

  12. Synthetic oligosaccharides as heparin-mimetics displaying anticoagulant properties.

    Science.gov (United States)

    Avci, Fikri Y; Karst, Nathalie A; Linhardt, Robert J

    2003-01-01

    Heparin and low molecular weight heparins are major clinical anticoagulants and the drugs of choice for the treatment of deep venous thrombosis. The discovery of an antithrombin binding domain in heparin focused interest on understanding the mechanism of heparin's antithrombotic/ anticoagulant activity. Various heparin-mimetic oligosaccharides have been prepared in an effort to replace polydisperse heparin and low molecular weight heparins with a structurally-defined anticoagulant. The goal of attaining a heparin-mimetic with no unwanted side-effects has also provided motivation for these efforts. This article reviews structure-activity relationship (SAR) of structurally-defined heparin-mimetic oligosaccharides. PMID:14529394

  13. Allosteric inhibition of factor XIa. Sulfated non-saccharide glycosaminoglycan mimetics as promising anticoagulants.

    Science.gov (United States)

    Al-Horani, Rami A; Gailani, David; Desai, Umesh R

    2015-08-01

    Recent development of sulfated non-saccharide glycosaminoglycan mimetics, especially sulfated pentagalloyl glucopyranoside (SPGG), as potent inhibitors of factor XIa (FXIa) (J. Med. Chem. 2013; 56:867-878 and J. Med. Chem. 2014; 57:4805-4818) has led to a strong possibility of developing a new line of factor XIa-based anticoagulants. In fact, SPGG represents the first synthetic, small molecule inhibitor that appears to bind in site remote from the active site. Considering that allosteric inhibition of FXIa is a new mechanism for developing a distinct line of anticoagulants, we have studied SPGG's interaction with FXIa with a goal of evaluating its pre-clinical relevance. Comparative inhibition studies with several glycosaminoglycans revealed the importance of SPGG's non-saccharide backbone. SPGG did not affect the activity of plasma kallikrein, activated protein C and factor XIIIa suggesting that SPGG-based anticoagulation is unlikely to affect other pathways connected with coagulation factors. SPGG's effect on APTT of citrated human plasma was also not dependent on antithrombin or heparin cofactor II. Interestingly, SPGG's anticoagulant potential was diminished by serum albumin as well as factor XI, while it could be reversed by protamine or polybrene, which implies possible avenues for developing antidote strategy. Studies with FXIa mutants indicated that SPGG engages Lys529, Arg530 and Arg532, but not Arg250, Lys252, Lys253 and Lys255. Finally, SPGG competes with unfractionated heparin, but not with polyphosphates and/or glycoprotein Ibα, for binding to FXIa. These studies enhance understanding on the first allosteric inhibitor of FXIa and highlight its value as a promising anticoagulant. PMID:25935648

  14. DABIGATRAN ETEXILATE: NEW DIRECT THROMBIN INHIBITORS ANTICOAGULANTS

    Directory of Open Access Journals (Sweden)

    Patel Kinjal B

    2011-04-01

    Full Text Available Thrombin plays a key role in thrombotic events, and therefore thrombin inhibition represents a therapeutic target for numerous thromboembolic diseases. Thrombin is responsible for the conversion of soluble fibrinogen to fibrin; clot stabilization through activation of factor XIII and the formation of cross-linkage among fibrin molecules; and the generation of additional thrombin through activation of factors V, VIII, and XI. Direct thrombin inhibitors are an innovative class of anticoagulants that bind directly to thrombin to inhibit its actions and impede the clotting process. Dabigatran is the first direct thrombin inhibitor, orally available first approval by US Food and Drugs Administration in 2010. Specifically and reversibly inhibits thrombin, so the duration of action is predictable. The anticoagulant effect correlates well with plasma drug concentrations, which implies an effective anticoagulation with low bleeding risk without major problems of interactions with other drugs. The predictable pharmacokinetics and pharmacodynamics characteristics of dabigatran may facilitate dental management of patients who until now have been in treatment with traditional anticoagulants, given that it doesn’t require routine laboratory monitoring in the vast majority of patients treated. They also present a profile of drug interactions very favorable.

  15. Extraction and anticoagulant activity of sulfated polysaccharides from Caulerpa cupressoides var. lycopodium (Vahl C. Agardh (Chlorophyceae - doi: 10.4025/actascibiolsci.v33i2.6243 Extraction and anticoagulant activity of sulfated polysaccharides from Caulerpa cupressoides var. lycopodium (Vahl C. Agardh (Chlorophyceae - doi: 10.4025/actascibiolsci.v33i2.6243

    Directory of Open Access Journals (Sweden)

    Norma Maria Barros Benevides

    2011-05-01

    Full Text Available The reportedly low standard quality of heparin (HEP for use in cardiac surgeries has led to concern in the Brazilian and international markets. Sulfated polysaccharides (SPs from seaweeds have been regarded as promising substitutes for HEP. The aim of this study was to sequentially extract total SPs (TSPs from Caulerpa cupressoides (Chlorophyceae with papain in 100 mM sodium acetate buffer (pH 5.0 containing 5 mM cysteine and 5 mM EDTA, followed by fractionation by ion-exchange chromatography (DEAE-cellulose, and then evaluate the anticoagulant potential of SP fractions by activated partial thromboplastin time (APTT using normal human plasma and compare it to standard HEP (193 IU mg-1. The obtained fractions were chemically characterized by chemical composition and agarose gel electrophoresis. The yield was 4.61%, and three fractions of SP (F I, F II and F III eluted with 0.50, 0.75 and 1.00 M of NaCl, respectively, were observed on chromatography profiles; however, differences in charge densities patterns and degree of resolution among them were revealed by electrophoresis. SPs were capable of modifying APTT only in fractions eluted with 0.75 M of NaCl, whose activities were 23.37 and 25.76 IU mg-1, respectively, and the charge density was prerequisite to activity. Therefore, C. cupressoides is a source of SPs possessing low anticoagulant potential compared to HEP.The reportedly low standard quality of heparin (HEP for use in cardiac surgeries has led to concern in the Brazilian and international markets. Sulfated polysaccharides (SPs from seaweeds have been regarded as promising substitutes for HEP. The aim of this study was to sequentially extract total SPs (TSPs from Caulerpa cupressoides (Chlorophyceae with papain in 100 mM sodium acetate buffer (pH 5.0 containing 5 mM cysteine and 5 mM EDTA, followed by fractionation by ion-exchange chromatography (DEAE-cellulose, and then evaluate the anticoagulant potential of SP fractions by activated

  16. [Direct oral anticoagulant associated bleeding].

    Science.gov (United States)

    Godier, A; Martin, A-C; Rosencher, N; Susen, S

    2016-07-01

    Direct oral anticoagulants (DOAC) are recommended for stroke prevention in atrial fibrillation and for the treatment of venous thromboembolism. However, they are associated with hemorrhagic complications. Management of DOAC-induced bleeding remains challenging. Activated or non-activated prothrombin concentrates are proposed, although their efficacy to reverse DOAC is uncertain. Therapeutic options also include antidotes: idarucizumab, antidote for dabigatran, has been approved for use whereas andexanet alpha, antidote for anti-Xa agents, and aripazine, antidote for all DOAC, are under development. Other options include hemodialysis for the treatment of dabigatran-associated bleeding and administration of oral charcoal if recent DOAC ingestion. DOAC plasma concentration measurement is necessary to guide DOAC reversal. We propose an update on DOAC-associated bleeding, integrating the availability of dabigatran antidote and the critical place of DOAC concentration measurements. PMID:27297642

  17. Structural Analysis and Anticoagulant Activity of Polysaccharides from Opuntia Milpa Alta%仙人掌多糖结构分析及抗凝血活性研究

    Institute of Scientific and Technical Information of China (English)

    蔡为荣; 谢亮亮; 汤坚

    2012-01-01

    [Objective] To analyze the components and structure of Opuntia Milpa Aha polysaccharide, and to study its anticoagulant activity. [ Method] The crude polysaccharides (CP) were prepared from Opuntia milpa alta using hot water extraction and ethanol precipitation method , purified by anion-exchange chromatography and gel filtration chromatography to study its monosaccharide composition, weight-average molecular weight distribution and main chain structure. And a preliminary study was conducted on the anticoagulant activity of polysaccharide components. [Result] WSP1, WSP2a and WSP3 polysaccharide components were obtained from CP by the anion-exchange chromatography and gel filtration chromatography. WSP1 was mainly composed of galactose with a weight-average molecular weight of 2. 32 × 106. WSP2a consisted of rhamnose, arabinose, xylose, mannose, glucose, galactose, glucuronic acid and galacturonic acid, the contents were 6. 3% , 32. 3% , 12.9% , 1.5%, 4.8% , 37. 1% , 0. 64% and 4. 4% , respectively. WSP3 mainly composed of arabinose, xylose, rhamnose and trace of glucose, mannose, uronic acid. The weight-average molecular weight of WSP2a and WSP3 was 1. 24 x 106 and 7.92 × 106, respectively. WSP2 prolonged the activated partial thromboplatin time ( APTT) and thrombin time (TT) , while had no significant effect on the pro-thrombin time (PT) in vitro, indicating that anticoagulant activity of WSP2 was worked by affecting the intrinsic coagulation system. The test of inhibition to the conversion of fibrinogen into thrombin showed that WSP2a and WSP3 had obvious anticoagulant activity. Methylation analy-. Sis indicated that the main chain of WSP2a was constituted of 1, 4-GalA, 1, 2-Rha and 1,2, 4-Rha. [ Conclusion] This study provided experimental basis for the optimization and development of polysaccharide resources from cactus.%[目的]分析仙人掌多糖组分和结构,并研究其抗凝血活性.[方法]以米邦塔仙人掌为试验材料,通过

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  19. Rational design of anticoagulant drugs using oligosaccharide chemistry.

    Science.gov (United States)

    El Hadri, Ahmed; Petitou, Maurice

    2011-01-01

    For a long time, heparin and low molecular weight heparins have been the drugs of choice for the management of thrombosis. Discovery of the antithrombin binding domain in heparin, a critical element in the anticoagulant activity of this polysaccharide, allowed a rational approach based on medicinal carbohydrate chemistry in the design of new anticoagulants. The fully synthetic pentasaccharide fondaparinux that selectively targets blood coagulation factor Xa was first to be developed as a drug. Fondaparinux was followed by various heparin mimicking oligosaccharides prepared with a view to replace polydisperse heparin and low molecular weight heparins by structurally-defined anticoagulants with no unwanted side-effects. PMID:21469438

  20. Nebulized anticoagulants limit coagulopathy but not inflammation in pseudomonas aeruginosa-induced pneumonia in rats.

    Science.gov (United States)

    Cornet, Alexander D; Hofstra, Jorrit J; Vlaar, Alexander P; van den Boogaard, Floor E; Roelofs, Joris J; van der Poll, Tom; Levi, Marcel; Groeneveld, A B Johan; Schultz, Marcus J

    2011-10-01

    Disturbed alveolar fibrin turnover is a characteristic feature of pneumonia. Inhibitors of coagulation could exert lung-protective effects via anticoagulant (inhibiting fibrin deposition) and possibly anti-inflammatory pathways, but could also affect host defense. In this randomized controlled in vivo laboratory study, rats were challenged intratracheally with Pseudomonas aeruginosa, inducing pneumonia, and randomized to local treatment with normal saline (placebo), recombinant human activated protein C (rh-APC), plasma-derived antithrombin (AT), heparin, or danaparoid. Induction of P. aeruginosa pneumonia resulted in activation of pulmonary coagulation and inhibition of pulmonary fibrinolysis, as reflected by increased pulmonary levels of thrombin-AT complexes and fibrin degradation products and decreased pulmonary levels plasminogen activator activity. Pseudomonas aeruginosa pneumonia was accompanied by systemic coagulopathy, since systemic levels of thrombin-AT complexes increased, and systemic levels of plasminogen activator activity decreased. Although rh-APC and plasma-derived AT potently limited pulmonary coagulopathy, neither heparin nor danaparoid affected net pulmonary fibrin turnover. Recombinant human APC also displayed systemic anticoagulant effects. Neither bacterial clearance nor pulmonary inflammation was affected by anticoagulant therapy. Nebulization of rh-APC or plasma-derived AT attenuated pulmonary coagulopathy, but not bacterial clearance or inflammation, in a rat model of P. aeruginosa pneumonia. PMID:21897338

  1. Clinical Safety of a High Dose of Phycocyanin-Enriched Aqueous Extract from Arthrospira (Spirulina) platensis: Results from a Randomized, Double-Blind, Placebo-Controlled Study with a Focus on Anticoagulant Activity and Platelet Activation.

    Science.gov (United States)

    Jensen, Gitte S; Drapeau, Cassandra; Lenninger, Miki; Benson, Kathleen F

    2016-07-01

    The goal for this study was to evaluate safety regarding anticoagulant activity and platelet activation during daily consumption of an aqueous cyanophyta extract (ACE), containing a high dose of phycocyanin. Using a randomized, double-blind, placebo-controlled study design, 24 men and women were enrolled after informed consent, and consumed either ACE (2.3 g/day) or placebo daily for 2 weeks. The ACE dose was equivalent to ∼1 g phycocyanin per day, chosen based on the highest dose Generally Recognized as Safe (GRAS) by the U.S. Food and Drug Administration. Consuming ACE did not alter markers for platelet activation (P-selectin expression) or serum P-selectin levels. No changes were seen for activated partial thromboplastin time, thrombin clotting time, or fibrinogen activity. Serum levels of aspartate transaminase (AST) showed a significant reduction after 2 weeks of ACE consumption (P < .001), in contrast to placebo where no changes were seen; the difference in AST levels between the two groups was significant at 2 weeks (P < .02). Reduced levels of alanine transaminase (ALT) were also seen in the group consuming ACE (P < .08). Previous studies showed reduction of chronic pain when consuming 1 g ACE per day. The higher dose of 2.3 g/day in this study was associated with significant reduction of chronic pain at rest and when physically active (P < .05). Consumption of ACE showed safety regarding markers pertaining to anticoagulant activity and platelet activation status, in conjunction with rapid and robust relief of chronic pain. Reduction in AST and ALT suggested improvement in liver function and metabolism. PMID:27362442

  2. Anticoagulant modulation of inflammation in severe sepsis

    OpenAIRE

    Allen, Karen S; Sawheny, Eva; Kinasewitz, Gary T

    2015-01-01

    Inflammation and coagulation are so tightly linked that the cytokine storm which accompanies the development of sepsis initiates thrombin activation and the development of an intravascular coagulopathy. This review examines the interaction between the inflammatory and coagulation cascades, as well as the role of endogenous anticoagulants in regulating this interaction and dampening the activity of both pathways. Clinical trials attempting to improve outcomes in patients with severe sepsis by ...

  3. Procoagulants and anticoagulants in fetal blood. A literature survey.

    Directory of Open Access Journals (Sweden)

    Waldemar Uszyński

    2010-05-01

    Full Text Available In intrauterine life, hemostasis is maintained by the same components as in extrauterine life (blood platelets, coagulation and fibrinolysis systems, involvement of the vascular wall; in the fetus, however, these components show significant differences of a quantitative/qualitative nature. In the present study, we surveyed the literature on the coagulation system in the fetus. We focused on the velocity of development of the coagulation system, being reflected in the increased concentration of all procoagulants and anticoagulants (a rise from approximately 20% in the middle of pregnancy to about 60% or more in the period of labor; exceptions: factors V, VIII and XIII which in the labor period reach the adult level and screening test results (prothrombin time, aPTT - activated prothrombin time, and thrombin time. Reference values were given for the 19-38 weeks of pregnancy and the labor term. Biochemical features of fetal fibrinogen and PIVKA factors were also discussed. The role of activated protein C (APC in the maintenance of balance between procoagulants and anticoagulants was postulated as well as the role of APC in the formation of thrombin activatable fibrinolysis inhibitor (TAFI.

  4. Oral and parenteral anticoagulants: New kids on the block

    Directory of Open Access Journals (Sweden)

    S Aditya

    2012-01-01

    Full Text Available Well-documented drawbacks of traditional anticoagulants have lead to the quest for an ideal anticoagulant resulting in a surge of novel anticoagulant molecules. These newer agents directly target specific steps in coagulation cascade and include newer low molecular weight heparins (adomiparin, ultra low molecular weight heparins (semuloparin, RO-14, inhibitors of activated factor II (dabigatran, AZD0837, X (rivaroxaban, apixaban, edoxaban, betrixaban, IX (REG1,2, XI (antisense oligonucleotides, BMS 262084, clavatadine A, VII/tissue factor (tifacogin, PCI 274836, and BMS 593214, V (recomodulin, solulin, VIII (TB402, dual thrombin/factor X inhibitors (EP21709, tanogitran, and newer vitamin K antagonists (tecarfarin. Direct thrombin inhibitors and Factor X inhibitors are the most clinically advanced. This article discusses the recent advances in the development of novel targets of anticoagulants. Medline, EMBASE, cochrane database, medscape, SCOPUS, and clinicaltrials.gov were searched using terms "anticoagulants", "blood coagulation inhibitors", "anticoagulants and venous thromboembolism", "anticoagulants and atrial fibrillation", and "′antithrombins." Journal articles published from 2007 to 2012 discussing pharmacology and/or clinical trials were screened.

  5. Design, synthesis, anticoagulant activity evaluation and molecular docking studies of a class of N-ethyl dabigatran derivatives.

    Science.gov (United States)

    Ren, Weixin; Ren, Yujie; Wang, Shuai

    2016-09-14

    A class of N-ethyl dabigatran derivatives was designed based on pharmacological strategies for inhibition of thrombin activity and the structure-activity relationship studies of the previous dabigatran derivatives. Activities of these novel compounds were predicted based on CoMFA model, and most of the compounds had comparable predicted activity with dabigatran. All of screened compounds were synthesized and characterized by (1)H NMR, (13)C NMR and HRMS. Subsequently, these compounds were evaluated inhibitory activity on thrombin. Among these compounds, 9a-9e, 9h, 9l-9n and 9p exhibited comparable inhibitory activity to dabigatran (IC50 = 1.20 nM), additionally, compound 9p (IC50 = 0.96 nM) exhibited better inhibitory activity than dabigatran. Moreover, compound 9p also exhibited a fairly good inhibitory activity for arteriovenous thrombosis with inhibition rate of (85.35 ± 0.72) %, which was comparable to that of dabigatran (85.07 ± 0.61) %. These results, along with related molecular docking studies, could provide an important basis for further development of compound 9p as a potent thrombin inhibitor.

  6. Recurrent thrombotic occlusion of a transjugular intrahepatic portosystemic stent-shunt due to activated protein C resistance

    Institute of Scientific and Technical Information of China (English)

    Elmar Siewert; Jan Salzmann; Edmund Purucker; Karl Schürmann; Siegfried Matern

    2005-01-01

    The transjugular intrahepatic portosystemic stent-shunt (TIPS) has successfully been used in the management of refractory variceal bleeding and ascites in patients with portal hypertension. Major drawbacks are the induction of hepatic encephalopathy and shunt dysfunction. We present a 59-year-old woman with alcoholic liver cirrhosis who received a TIPS because of recurrent bleeding from esophageal varices. Stent occlusion occurred 4 mo after placement of the TIPS. Laboratory testing revealed resistance to activated protein C (APC). Combination therapy with low-dose enoxaparin and clopidogrel could not prevent her recurrent stent occlusion. Finally, therapy with high-dose enoxaparin was sufficient to prevent further shunt complications up to now (follow-up period of 1 year). In conclusion, early occlusion of a TIPS warrants testing for thrombophilia. If risk factors are confirmed,anticoagulation should be intensified. There are currently no evidence-based recommendations regarding the best available anticoagulant therapy and surveillance protocol for patients with TIPS.

  7. Molecular dynamics and docking simulation of a natural variant of Activated Protein C with impaired protease activity: implications for integrin-mediated antiseptic function.

    Science.gov (United States)

    D'Ursi, Pasqualina; Orro, Alessandro; Morra, Giulia; Moscatelli, Marco; Trombetti, Gabriele; Milanesi, Luciano; Rovida, Ermanna

    2015-01-01

    Activated Protein C (APC) is a multifunctional serine protease, primarily known for its anticoagulant function in the coagulation system. Several studies have already elucidated its role in counteracting apoptosis and inflammation in cells, while significant effort is still ongoing for defining its involvement in sepsis. Earlier literature has shown that the antiseptic function of APC is mediated by its binding to leukocyte integrins, which is due to the presence of the integrin binding motif Arg-Gly-Asp at the N-terminus of the APC catalytic chain. Many natural mutants have been identified in patients with Protein C deficiency diagnosis including a variant of specificity pocket (Gly216Asp). In this work, we present a molecular model of the complex of APC with αVβ3 integrin obtained by protein-protein docking approach. A computational analysis of this variant is hereby presented, based on molecular dynamics and docking simulations, aiming at investigating the effects of the Gly216Asp mutation on the protein conformation and inferring its functional implications. Our study shows that such mutation is likely to impair the protease activity while preserving the overall protein fold. Moreover, superposition of the integrin binding motifs in wild-type and mutant forms suggests that the interaction with integrin can still occur and thus the mutant is likely to retain its antiseptic function related to the neutrophyl integrin binding. Therapeutic applications could result in this APC mutant which retains antiseptic function without anticoagulant side effects.

  8. Degradation of Activated Protein Kinases by Ubiquitination

    OpenAIRE

    Lu, Zhimin; Hunter, Tony

    2009-01-01

    Protein kinases are important regulators of intracellular signal transduction pathways and play critical roles in diverse cellular functions. Once a protein kinase is activated, its activity is subsequently downregulated through a variety of mechanisms. Accumulating evidence indicates that the activation of protein kinases commonly initiates their downregulation via the ubiquitin/proteasome pathway. Failure to regulate protein kinase activity or expression levels can cause human diseases.

  9. Anticoagulants and the propagation phase of thrombin generation.

    Directory of Open Access Journals (Sweden)

    Thomas Orfeo

    Full Text Available The view that clot time-based assays do not provide a sufficient assessment of an individual's hemostatic competence, especially in the context of anticoagulant therapy, has provoked a search for new metrics, with significant focus directed at techniques that define the propagation phase of thrombin generation. Here we use our deterministic mathematical model of tissue-factor initiated thrombin generation in combination with reconstructions using purified protein components to characterize how the interplay between anticoagulant mechanisms and variable composition of the coagulation proteome result in differential regulation of the propagation phase of thrombin generation. Thrombin parameters were extracted from computationally derived thrombin generation profiles generated using coagulation proteome factor data from warfarin-treated individuals (N = 54 and matching groups of control individuals (N = 37. A computational clot time prolongation value (cINR was devised that correlated with their actual International Normalized Ratio (INR values, with differences between individual INR and cINR values shown to derive from the insensitivity of the INR to tissue factor pathway inhibitor (TFPI. The analysis suggests that normal range variation in TFPI levels could be an important contributor to the failure of the INR to adequately reflect the anticoagulated state in some individuals. Warfarin-induced changes in thrombin propagation phase parameters were then compared to those induced by unfractionated heparin, fondaparinux, rivaroxaban, and a reversible thrombin inhibitor. Anticoagulants were assessed at concentrations yielding equivalent cINR values, with each anticoagulant evaluated using 32 unique coagulation proteome compositions. The analyses showed that no anticoagulant recapitulated all features of warfarin propagation phase dynamics; differences in propagation phase effects suggest that anticoagulants that selectively target fXa or

  10. Comparing new anticoagulants.

    Science.gov (United States)

    Wooten, James M

    2012-12-01

    For years, the pharmaceutical industry has been trying to find a safe and effective drug to replace warfarin. Although warfarin is an effective anticoagulant, its pharmacology, adverse effects, and risk profiles dictate that patients taking this medication must be monitored judiciously. The US Food and Drug Administration has approved two drugs for commercial use, dabigatran and rivaroxaban, that will compete directly with warfarin for use in specific indications. Because of direct marketing to patients, physicians are being asked to comment on these new medications. This brief review illustrates the data available for the two new drugs when compared to warfarin for the specified indications. For some patients, these drugs may be highly beneficial and offer an excellent alternative to warfarin. For others, warfarin may still be the preferred drug. PMID:23211502

  11. [Novel oral anticoagulants and their use in the perioperative setting].

    Science.gov (United States)

    Schellong, Sebastian M; Haas, Sylvia

    2012-04-01

    Novel oral anticoagulants (NOACs) have become available for prevention of venous thromboembolism after major orthopaedic surgery, treatment of venous thromboembolism, and stroke prevention in patients with atrial fibrillation. The thrombin inhibitor Dabigatran has a plasma half life of 11-14 hours which prolongs significantly in renal insufficiency. The two Xa-inhibitors Rivaroxaban and Apixaban have slightly shorter half lifes, and renal elimination is confined to about 30% of active drug. Prior to elective surgery, drug intake needs to be halted. The time period depends on the actual drug half life in that particular situation. Bridging anticoagulation is not necessary. The management of bleeding complications does not differ from that in other anticoagulants. The most uncertainties in clinical practice will arise from the fact that NOACs derange the global clotting tests without any conclusive information about the actual intensity of anticoagulation. PMID:22504623

  12. Beyond heparin and warfarin: the new generation of anticoagulants.

    Science.gov (United States)

    Weitz, Jeffrey I; Linkins, Lori-Ann

    2007-03-01

    Heparin and warfarin are widely used for the prevention and treatment of venous and arterial thromboembolism. Although effective, both agents have important limitations; for example, both drugs must be monitored, which is inconvenient for patients and for physicians. Heparin requires parenteral administration and can cause heparin-induced thrombocytopenia, an immune-mediated process that can lead to life-threatening thrombosis. Warfarin also has its limitations. Due to its slow onset of action, warfarin must be overlapped with heparin (or another rapidly acting anticoagulant) when treating patients with established thrombosis or who are at high risk for thrombosis. Warfarin dosing is variable because its activity is influenced by dietary intake of vitamin K, genetic polymorphisms in enzymes that are involved in its metabolism and numerous drug-drug interactions that promote or reduce its activity. New anticoagulants have been developed to overcome these problems. Building on a better understanding of coagulation pathways, advances in structure-based drug design and information derived from natural anticoagulants isolated from hematophagous organisms, most of the new anticoagulants target specific coagulation enzymes. Focussing on drugs that have at least completed Phase II evaluation, this article briefly reviews the coagulation pathways and its natural regulators; outlines the limitations of existing anticoagulants and identifies the opportunities for new ones; highlights the properties of selected new anticoagulants; describes the clinical trial results with these agents; and provides a perspective on their potential strengths and weaknesses. PMID:17302522

  13. New Insights into the Pros and Cons of the Clinical Use of Vitamin K Antagonists (VKAs) Versus Direct Oral Anticoagulants (DOACs).

    Science.gov (United States)

    van Gorp, Rick H; Schurgers, Leon J

    2015-11-17

    Vitamin K-antagonists (VKA) are the most widely used anticoagulant drugs to treat patients at risk of arterial and venous thrombosis for the past 50 years. Due to unfavorable pharmacokinetics VKA have a small therapeutic window, require frequent monitoring, and are susceptible to drug and nutritional interactions. Additionally, the effect of VKA is not limited to coagulation, but affects all vitamin K-dependent proteins. As a consequence, VKA have detrimental side effects by enhancing medial and intimal calcification. These limitations stimulated the development of alternative anticoagulant drugs, resulting in direct oral anticoagulant (DOAC) drugs, which specifically target coagulation factor Xa and thrombin. DOACs also display non-hemostatic vascular effects via protease-activated receptors (PARs). As atherosclerosis is characterized by a hypercoagulable state indicating the involvement of activated coagulation factors in the genesis of atherosclerosis, anticoagulation could have beneficial effects on atherosclerosis. Additionally, accumulating evidence demonstrates vascular benefit from high vitamin K intake. This review gives an update on oral anticoagulant treatment on the vasculature with a special focus on calcification and vitamin K interaction.

  14. New Insights into the Pros and Cons of the Clinical Use of Vitamin K Antagonists (VKAs Versus Direct Oral Anticoagulants (DOACs

    Directory of Open Access Journals (Sweden)

    Rick H. van Gorp

    2015-11-01

    Full Text Available Vitamin K-antagonists (VKA are the most widely used anticoagulant drugs to treat patients at risk of arterial and venous thrombosis for the past 50 years. Due to unfavorable pharmacokinetics VKA have a small therapeutic window, require frequent monitoring, and are susceptible to drug and nutritional interactions. Additionally, the effect of VKA is not limited to coagulation, but affects all vitamin K-dependent proteins. As a consequence, VKA have detrimental side effects by enhancing medial and intimal calcification. These limitations stimulated the development of alternative anticoagulant drugs, resulting in direct oral anticoagulant (DOAC drugs, which specifically target coagulation factor Xa and thrombin. DOACs also display non-hemostatic vascular effects via protease-activated receptors (PARs. As atherosclerosis is characterized by a hypercoagulable state indicating the involvement of activated coagulation factors in the genesis of atherosclerosis, anticoagulation could have beneficial effects on atherosclerosis. Additionally, accumulating evidence demonstrates vascular benefit from high vitamin K intake. This review gives an update on oral anticoagulant treatment on the vasculature with a special focus on calcification and vitamin K interaction.

  15. Lupus anticoagulants: pathogenesis and laboratory diagnosis.

    Science.gov (United States)

    Court, E L

    1997-12-01

    The pathogenesis of the lupus anticoagulant (LA) has been the focus of much research over the past decade, and a plethora of laboratory tests have been developed to detect it. This essay reviews the nature of LA and its pathogenesis, and a number of approaches employed in its diagnosis. These range from well established tests such as the kaolin clotting time (KCT), activated partial thromboplastin time (APTT) and tissue thromboplastin inhibition test (TTI), to the 'newer' tests such as the dilute Russell's viper venom time (DRVVT) and more recent snake venom tests such as the textarin/ecarin ratio and Taipan snake venom time (TSVT). The criteria for diagnosis are discussed, including pre-analytical variables such as sample preparation, and the effects of therapeutic anticoagulants used to treat thrombotic manifestations of the syndrome or an underlying disease process. PMID:9624740

  16. Activated protein C attenuates acute ischaemia reperfusion injury in skeletal muscle.

    LENUS (Irish Health Repository)

    Dillon, J P

    2012-02-03

    Activated protein C (APC) is an endogenous anti-coagulant with anti-inflammatory properties. The purpose of the present study was to evaluate the effects of activated protein C in the setting of skeletal muscle ischaemia reperfusion injury (IRI). IRI was induced in rats by applying rubber bands above the levels of the greater trochanters bilaterally for a period of 2h followed by 12h reperfusion. Treatment groups received either equal volumes of normal saline or activated protein C prior to tourniquet release. Following 12h reperfusion, muscle function was assessed electrophysiologically by electrical field stimulation. The animals were then sacrificed and skeletal muscle harvested for evaluation. Activated protein C significantly attenuated skeletal muscle reperfusion injury as shown by reduced myeloperoxidase content, wet to dry ratio and electrical properties of skeletal muscle. Further in vitro work was carried out on neutrophils isolated from healthy volunteers to determine the direct effect of APC on neutrophil function. The effects of APC on TNF-alpha stimulated neutrophils were examined by measuring CD18 expression as well as reactive oxygen species generation. The in vitro work demonstrated a reduction in CD18 expression and reactive oxygen species generation. We conclude that activated protein C may have a protective role in the setting of skeletal muscle ischaemia reperfusion injury and that this is in part mediated by a direct inhibitory effect on neutrophil activation.

  17. Anticoagulation therapy in intra-aortic balloon counterpulsation:Does IABP really need anti-coagulation?

    Institute of Scientific and Technical Information of China (English)

    JIANG Chen-yang(蒋晨阳); ZHAO Li-li(赵莉莉); WANG Jian-an(王建安); SAN Jiang(单江); MOHAMMOD Balgaith

    2003-01-01

    Objective: To investigate if intra-aortic balloon pump(IABP) is contraindicated without anticoagulation therapy. Methods: Some 153 IABP patients in the King Abdulaziz Cardiac Center(KSA) were randomly assigned into two groups. Anticoagulation group(Group A) consisted of 71 patients who were given heparin intravenously with target aPTT 50-70 seconds. Non-anticoagulation group(Group B) consisted of 82 patients without intravenous heparin during balloon pumping. Hematological parameters including platelet count, D-dimer, Plasminogen activator inhibitor-1(PAI-1) and fibrinogen degradation products(FDP) were checked respectively at the point of baseline, 24 hours, 48 hours and 24 hours post IABP counterpulsation. Clot deposits on balloon surface, vascular complications from IABP including bleeding and limb ischemia were recorded. Results: Platelet count and PAI-1 level decreased at 24 hours and 48 hours in both groups (P0.05). Three patients in Group A and 2 patients in Group B developed minor limb ischemia(P>0.05). No major limb ischemia in either group. Two patients in Group A suffered major bleeding and required blood transfusion or surgical intervention, whereas no patient had major bleeding in Group B. Eight patients had minor bleeding in Group A, but only 2 patients in Group B(P<0.05). No clot deposit developed on IABP surface in either group. Conclusion: IABP is safe without routine anticoagulation therapy. Selecting appropriate artery approach and early detection intervention are key methods for preventing complications.

  18. Anticoagulation therapy in intra-aortic balloon counterpulsation: Does IABP really need anti-coagulation

    Institute of Scientific and Technical Information of China (English)

    蒋晨阳; 赵莉莉; 王建安; 单江; MOHAMMODBalgaith

    2003-01-01

    Objective: To investigate if intra-aortic balloon pump(IABP) is contraindicated without anticoag-ulation therapy. Methods: Some 153 IABP patients in the King Abdulaziz Cardiac Center(KSA) were random-ly assigned into two groups. Anticoagulation group( Group A) consisted of 71 patients who were given heparin intravenously with target aPTT 50 - 70 seconds. Non-anticoagulation group( Group B) consisted of 82 patients without intravenous heparin during balloon pumping. Hematological parameters including platelet count, D-dimer, Plasminogen activator inhibitor-1 (PAI-1) and fibrinogen degradation products(FDP) were checked respectively at the point of baseline, 24 hours, 48 hours and 24 hours post IABP counterpulsation. Clot deposits on balloon surface, vascular complications from IABP including bleeding and limb ischemia were recorded.Results: Platelet count and PAI-1 level decreased at 24 hours and 48 hours in both groups ( P 0.05) . Three patients in Group A and 2 patients in Group B developed minor limb ischemia( P > 0.05). No major limb ischemia in either group. Two patients in Group A suffered major bleeding and required blood transfusion or surgical intervention, whereas no patient had major bleeding in Group B. Eight patients had minor bleeding in Group A, but only 2 patients in Group B ( P <0.05). No clot deposit developed on IABP surface in either group. Conclusion: IABP is safe without routine anticoagulation therapy. Selecting appropriate artery approach and early detection intervention are key methods for preventing complications.

  19. Physiological roles of mitogen-activated-protein-kinase-activated p38-regulated/activated protein kinase

    Institute of Scientific and Technical Information of China (English)

    Sergiy; Kostenko; Gianina; Dumitriu; Kari; Jenssen; Lgreid; Ugo; Moens

    2011-01-01

    Mitogen-activated protein kinases(MAPKs)are a family of proteins that constitute signaling pathways involved in processes that control gene expression,cell division, cell survival,apoptosis,metabolism,differentiation and motility.The MAPK pathways can be divided into conventional and atypical MAPK pathways.The first group converts a signal into a cellular response through a relay of three consecutive phosphorylation events exerted by MAPK kinase kinases,MAPK kinase,and MAPK.Atypical MAPK pathways are not organized into this three-tiered cascade.MAPK that belongs to both conventional and atypical MAPK pathways can phosphorylate both non-protein kinase substrates and other protein kinases.The latter are referred to as MAPK-activated protein kinases.This review focuses on one such MAPK-activated protein kinase,MAPK-activated protein kinase 5(MK5)or p38-regulated/activated protein kinase(PRAK).This protein is highly conserved throughout the animal kingdom and seems to be the target of both conventional and atypical MAPK pathways.Recent findings on the regulation of the activity and subcellular localization,bona fide interaction partners and physiological roles of MK5/PRAK are discussed.

  20. Protein-water dynamics in antifreeze protein III activity

    Science.gov (United States)

    Xu, Yao; Bäumer, Alexander; Meister, Konrad; Bischak, Connor G.; DeVries, Arthur L.; Leitner, David M.; Havenith, Martina

    2016-03-01

    We combine Terahertz absorption spectroscopy (THz) and molecular dynamics (MD) simulations to investigate the underlying molecular mechanism for the antifreeze activity of one class of antifreeze protein, antifreeze protein type III (AFP-III) with a focus on the collective water hydrogen bond dynamics near the protein. After summarizing our previous work on AFPs, we present a new investigation of the effects of cosolutes on protein antifreeze activity by adding sodium citrate to the protein solution of AFP-III. Our results reveal that for AFP-III, unlike some other AFPs, the addition of the osmolyte sodium citrate does not affect the hydrogen bond dynamics at the protein surface significantly, as indicated by concentration dependent THz measurements. The present data, in combination with our previous THz measurements and molecular simulations, confirm that while long-range solvent perturbation is a necessary condition for the antifreeze activity of AFP-III, the local binding affinity determines the size of the hysteresis.

  1. Avaliação do desempenho dos reagentes do tempo de tromboplastina parcial ativada utilizados para detectar o anticoagulante lúpico Assessment of the performance of reagents of activated partial thromboplastin time used to detect the lupus anticoagulant

    Directory of Open Access Journals (Sweden)

    Fernanda Chiuso

    2005-06-01

    Full Text Available INTRODUÇÃO: O anticoagulante lúpico é uma imunoglobulina pertencente à família dos anticorpos antifosfolípides. A sua ação in vitro é interferir nos testes de coagulação dependentes de fosfolípides. O tempo de tromboplastina parcial ativada (TTPA é um teste utilizado como screening na pesquisa do anticoagulante lúpico. Os reagentes utilizados neste teste apresentam grandes variações quanto à sensibilidade. OBJETIVO: Avaliar o desempenho dos reagentes do TTPA e detectar a presença do anticoagulante lúpico através de diferentes testes da coagulação. MATERIAL E MÉTODO: A pesquisa do anticoagulante lúpico foi realizada em 50 amostras plasmáticas de pacientes do sexo feminino através dos testes do TTPA, do tempo de coagulação do caulim (TCC, do tempo de tromboplastina parcial ativada diluída (TTPAd e do tempo do veneno da víbora de Russel diluído (TVVRd. Três cefalinas comerciais foram avaliadas pelos testes do TTPA e do TTPAd. Na comparação entre os reagentes estudados foi aplicado o cálculo do intervalo de confiança (95%. RESULTADOS: Os três reagentes avaliados apresentaram boa concordância e os métodos utilizados responderam bem à pesquisa do anticoagulante lúpico. DISCUSSÃO E CONCLUSÃO: As três cefalinas comerciais avaliadas podem ser utilizadas na rotina laboratorial para a pesquisa do anticoagulante lúpico.INTRODUCTION: The lupus anticoagulant is an immunoglobin which belongs to the antiphospholid antibodies family. Its in vitro function is to interfere with coagulation tests that are dependent on phospholipids. The activated partial thromboplastin time (APTT is a test used as screening on lupus anticoagulant research. Reagents used in this test demonstrate wide sensitivity ranges. OBJECTIVE: To assess the performance of APTT reagents and detect the presence of lupus anticoagulant through various coagulation tests. MATERIAL AND METHOD: The lupus anticoagulant research was performed in plasma from 50

  2. Human activated protein C variants in a rat model of arterial thrombosis

    Directory of Open Access Journals (Sweden)

    Dahlbäck Björn

    2008-10-01

    Full Text Available Abstract Background Activated protein C (APC inhibits coagulation by degrading activated factor V (FVa and factor VIII (FVIIIa, protein S (PS functioning as a cofactor to APC. Methods By mutagenesis of the vitamin K-dependent Gla domain of APC, we have recently created an APC variant having enhanced anticoagulant activity due to increased affinity for negatively charged phospholipid membranes. In the present study, the potential antithrombotic effects of this APC variant, and of a variant APC that is additionally mutated in the serine protease domain, have been evaluated in a blind randomized study in a rat model of arterial thrombosis. In this model, we have previously found the combination of bovine APC and PS to be highly antithrombotic. Four treatment groups each containing 10 rats were, in a blind random fashion, given intravenous bolus injections of wild-type or mutant variants of APC (0.8 mg/kg together with human PS (0.6 mg/kg or human PS (0.6 mg/kg alone. A control group with 20 animals where given vehicle only. Results A trend to increased patency rates was noted in a group receiving one of the APC variants, but it did not reach statistical significance. Conclusion In conclusion, administration of human APC variants having enhanced anticoagulant efficacy together with human PS in a rat model of arterial thrombosis did not give an efficient antithrombotic effect. The lack of effect may be due to species-specific differences between the human protein C system and the rat hemostatic system.

  3. Pharmacology of new oral anticoagulants: mechanism of action, pharmacokinetics, pharmacodynamics

    Directory of Open Access Journals (Sweden)

    Luca Masotti

    2013-12-01

    Full Text Available Due to their mechanism of action, the new oral anticoagulants are named direct oral anticoagulants (DOACs. Dabigatran is a selective, competitive, direct inhibitor of thrombin (Factor IIa while rivaroxaban, apixaban and edoxaban act by directly inhibiting the activated Factor X (FXa in a selective and competitive manner. DOACs have a relatively short half-life and almost immediate anticoagulant activity, and rapidly reach the plasma peak concentration. Therefore, they do not need a phase of overlapping with parenteral anticoagulants. After their withdrawal, their removal is sufficiently rapid, although influenced by renal function. Dabigatran is the only DOACs to be administered as a pro-drug and becomes active after drug metabolization. The route of elimination of dabigatran is primarily renal, whereas FXa inhibitors are mainly eliminated by the biliary-fecal route. The drug interactions of DOACs are mainly limited to drugs that act on P-glycoprotein for dabigatran and on P-glycoprotein and/or cytochrome P3A4 for anti-Xa. DOACs have no interactions with food. Given their linear pharmacodynamics, with a predictable dose/response relationship and anticoagulant effect, DOACs are administered at a fixed dose and do not require routine laboratory monitoring.

  4. Activity assay of membrane transport proteins

    Institute of Scientific and Technical Information of China (English)

    Hao Xie

    2008-01-01

    Membrane transport proteins are integral membrane proteins and considered as potential drug targets. Activity assay of transport proteins is essential for developing drugs to target these proteins. Major issues related to activity assessment of transport proteins include availability of transporters,transport activity of transporters, and interactions between ligands and transporters. Researchers need to consider the physiological status of proteins (bound in lipid membranes or purified), availability and specificity of substrates, and the purpose of the activity assay (screening, identifying, or comparing substrates and inhibitors) before choosing appropriate assay strategies and techniques. Transport proteins bound in vesicular membranes can be assayed for transporting substrate across membranes by means of uptake assay or entrance counterflow assay. Alternatively, transport proteins can be assayed for interactions with ligands by using techniques such as isothermal titration calorimetry, nuclear magnetic resonance spectroscopy, or surface plasmon resonance. Other methods and techniques such as fluorometry, scintillation proximity assay, electrophysiological assay, or stopped-flow assay could also be used for activity assay of transport proteins. In this paper the major strategies and techniques for activity assessment of membrane transport proteins are reviewed.

  5. Interference from lupus anticoagulant on von Willebrand factor measurement in splenic marginal zone lymphoma

    DEFF Research Database (Denmark)

    Vinholt, Pernille J; Nybo, Mads

    2015-01-01

    We present a case concerning a patient with splenic marginal zone lymphoma (SMZL) and isolated prolonged activated partial thromboplastin time (aPTT) caused by lupus anticoagulant. Von Willebrand factor (VWF) activity and antigen were immeasurable by latex particle immunoturbidimetric assays......, and several coagulation factor levels were decreased. However, VWF activity and antigen were normal when analyzed by other methods. Also, coagulation factor levels were normal if an aPTT reagent with low lupus anticoagulant sensitivity or a chromogenic method was applied. Altogether, the initial findings were...... because of lupus anticoagulant interference and in fact, the patient had normal VWF activity and coagulation status. Interference of lupus anticoagulant in clot-based assays is well known but has not previously been described in VWF assays. This is furthermore the first report in which lupus anticoagulant...

  6. Colonoscopic polypectomy in anticoagulated patients

    Institute of Scientific and Technical Information of China (English)

    Shai Friedland; Daniel Sedehi; Roy Soetikno

    2009-01-01

    AIM: To review our experience performing polypectomy in anticoagulated patients without interruption of anticoagulation.METHODS: Retrospective chart review at the Veterans Affairs Palo Alto Health Care System. Two hundred and twenty five polypectomies were performed in 123 patients. Patients followed a standardized protocol that included stopping warfarin for 36 h to avoid supratherapeutic anticoagulation from the bowel preparation. Patients with lesions larger than 1 cm were generally rescheduled for polypectomy off warfarin. Endoscopic clips were routinely applied prophylactically.RESULTS: One patient (0.8%, 95% CI: 0.1%-4.5%)developed major post-polypectomy bleeding that required transfusion. Two others (1.6%, 95% CI:0.5%-5.7%) had self-limited hematochezia at home and did not seek medical attention. The average polyp size was 5.1 ± 2.2 mm.

  7. [Direct oral anticoagulants in cardiology].

    Science.gov (United States)

    Kiss, Róbert Gábor

    2016-09-01

    Antithrombotic drug therapy is a main cornerstone - sometimes a fairly uneven cornerstone - of today's clinical practice. Patients treated with antithrombotic drugs appear sometimes unawaited at those of our colleagues, who are not necessarily experts of this narrow field. Furthermore, new and newer molecules of antiplatelet and anticoagulant medicines have come into practice, frequently in combination. This dramatic development has been important to patients; pharmacological - and recently nonpharmacological - antithrombotic treatment has paved the way to improve current modalities in cardiology. Combining elements of the "old four" (heparin, coumadin, aspirin, clopidogrel) have been the basis of any improvement for a long time. Nowadays, there has been an involvement of new drugs, direct oral anticoagulants into practice. It is time now to catch up in using new anticoagulants, regardless of our current speciality in medicine. Orv. Hetil., 2016, 157(38), 1507-1510. PMID:27640616

  8. 3K3A-activated protein C stimulates postischemic neuronal repair by human neural stem cells in mice

    DEFF Research Database (Denmark)

    Wang, Yaoming; Zhao, Zhen; Rege, Sanket V;

    2016-01-01

    profile in humans, 3K3A-APC has advanced to clinical trials as a neuroprotectant in ischemic stroke. Recently, 3K3A-APC has been shown to stimulate neuronal production by human neural stem and progenitor cells (NSCs) in vitro via a PAR1-PAR3-sphingosine-1-phosphate-receptor 1-Akt pathway, which suggests......Activated protein C (APC) is a blood protease with anticoagulant activity and cell-signaling activities mediated by the activation of protease-activated receptor 1 (F2R, also known as PAR1) and F2RL1 (also known as PAR3) via noncanonical cleavage. Recombinant variants of APC, such as the 3K3A......-APC (Lys191-193Ala) mutant in which three Lys residues (KKK191-193) were replaced with alanine, and/or its other mutants with reduced (>90%) anticoagulant activity, engineered to reduce APC-associated bleeding risk while retaining normal cell-signaling activity, have shown benefits in preclinical models...

  9. Activity-Based Protein Profiling of Microbes

    Energy Technology Data Exchange (ETDEWEB)

    Sadler, Natalie C.; Wright, Aaron T.

    2015-02-01

    Activity-Based Protein Profiling (ABPP) in conjunction with multimodal characterization techniques has yielded impactful findings in microbiology, particularly in pathogen, bioenergy, drug discovery, and environmental research. Using small molecule chemical probes that react irreversibly with specific proteins or protein families in complex systems has provided insights in enzyme functions in central metabolic pathways, drug-protein interactions, and regulatory protein redox, for systems ranging from photoautotrophic cyanobacteria to mycobacteria, and combining live cell or cell extract ABPP with proteomics, molecular biology, modeling, and other techniques has greatly expanded our understanding of these systems. New opportunities for application of ABPP to microbial systems include: enhancing protein annotation, characterizing protein activities in myriad environments, and reveal signal transduction and regulatory mechanisms in microbial systems.

  10. Anticoagulation in Older Adults with Multimorbidity.

    Science.gov (United States)

    Parks, Anna L; Fang, Margaret C

    2016-05-01

    The number of patients with atrial fibrillation (AF) who are of advanced age or have multiple comorbidities is expected to increase substantially. Older patients with AF generally gain a net benefit from anticoagulation. Guidelines typically recommend anticoagulation. There are multiple challenges in the safe use of anticoagulation in frail patients, including bleeding risk, monitoring and adherence, and polypharmacy. Although there are options for chronic oral anticoagulation, clinicians must understand the unique advantages and disadvantages of these medications when developing a management plan. This article reviews issues surrounding the appropriate use and selection of anticoagulants in complex older patients with AF. PMID:27113150

  11. Hydrogen peroxide activates activator protein-1 and mitogen-activated protein kinases in pancreatic stellate cells.

    Science.gov (United States)

    Kikuta, Kazuhiro; Masamune, Atsushi; Satoh, Masahiro; Suzuki, Noriaki; Satoh, Kennichi; Shimosegawa, Tooru

    2006-10-01

    Activated pancreatic stellate cells (PSCs) are implicated in the pathogenesis of pancreatic inflammation and fibrosis, where oxidative stress is thought to play a key role. Reactive oxygen species such as hydrogen peroxide (H(2)O(2)) may act as a second messenger to mediate the actions of growth factors and cytokines. But the role of reactive oxygen species in the activation and regulation of cell functions in PSCs remains largely unknown. We here examined the effects of H(2)O(2) on the activation of signal transduction pathways and cell functions in PSCs. PSCs were isolated from the pancreas of male Wistar rats, and used in their culture-activated, myofibroblast-like phenotype unless otherwise stated. Activation of transcription factors was examined by electrophoretic mobility shift assay and luciferase assay. Activation of mitogen-activated protein (MAP) kinases was assessed by Western blotting using anti-phosphospecific antibodies. The effects of H(2)O(2) on proliferation, alpha(1)(I)procollagen gene expression, and monocyte chemoattractant protein-1 production were evaluated. The effect of H(2)O(2) on the transformation of freshly isolated PSCs in culture was also assessed. H(2)O(2) at non-cytotoxic concentrations (up to 100 microM) induced oxidative stress in PSCs. H(2)O(2) activated activator protein-1, but not nuclear factor kappaB. In addition, H(2)O(2) activated three classes of MAP kinases: extracellular signal-regulated kinase, c-Jun N-terminal kinase, and p38 MAP kinase. H(2)O(2) induced alpha(1)(I)procollagen gene expression but did not induce proliferation or monocyte chemoattractant protein-1 production. H(2)O(2) did not initiate the transformation of freshly isolated PSCs to myofibroblast-like phenotype. Specific activation of these signal transduction pathways and collagen gene expression by H(2)O(2) may play a role in the pathogenesis of pancreatic fibrosis.

  12. Pharmacokinetic and pharmacodynamic properties of oral anticoagulants, especially phenprocoumon.

    Science.gov (United States)

    Haustein, K O

    1999-01-01

    Anticoagulants of the cumarin-type (warfarin, phenprocoumon, and acenocoumarol) are drugs for the long-term treatment and prevention of thromboembolic disorders. Because of their narrow therapeutic range, many patients have bleedings of variable severity or have recurrent thrombotic events. For this reason, the study of the pharmacokinetic parameters of phenprocoumon (PPC), considering its influence on blood clotting factors, is of high interest. The elimination kinetics of PPC, its interaction with phytomenadion (vitamin K), and the pharmacokinetic behavior of the anticoagulant under steady-state conditions have been investigated in studies with healthy volunteers and patients taking anticoagulants. The maintenance dose and the plasma levels of PPC were correlated with prothrombin time (PT) in 89 patients treated with PPC. Varying parameters in each patient (e.g., elimination kinetics of PPC, activity of the cumarin-dependent blood-clotting factors, endogenous phytomenadion stores), render it impossible to use a different means of monitoring than that of PT determination. PMID:10327214

  13. Computational Introduction of Catalytic Activity into Proteins.

    Science.gov (United States)

    Bertolani, Steve J; Carlin, Dylan Alexander; Siegel, Justin B

    2016-01-01

    Recently, there have been several successful cases of introducing catalytic activity into proteins. One method that has been used successfully to achieve this is the theozyme placement and enzyme design algorithms implemented in Rosetta Molecular Modeling Suite. Here, we illustrate how to use this software to recapitulate the placement of catalytic residues and ligand into a protein using a theozyme, protein scaffold, and catalytic constraints as input. PMID:27094294

  14. Evaluation of anticoagulant control in a pharmacist operated anticoagulant clinic.

    OpenAIRE

    Radley, A S; Hall, J; Farrow, M.; Carey, P J

    1995-01-01

    AIMS--To compare the quality of outpatient anticoagulant control before and after the transfer of dosing responsibility to designated trained pharmacists from rotating junior medical staff. METHODS--All International Normalised Ratio (INR) values for an eight month period either side of the staff changeover were assessed for precision of therapeutic control according to described standards. Allowing for patient associated effects, observed and expected frequencies of "successful" control for ...

  15. Neonatal renal vein thrombosis: role of anticoagulation and thrombolysis--an institutional review.

    Science.gov (United States)

    Bidadi, Behzad; Nageswara Rao, Amulya A; Kaur, Dominder; Khan, Shakila P; Rodriguez, Vilmarie

    2016-02-01

    Neonatal renal vein thrombosis (NRVT) is a rare thromboembolic complication in the neonatal period, and sequelae from renal dysfunction can cause significant morbidity. The authors retrospectively reviewed 10 patients with NRVT treated at their institution. The majority of the cohort were male (n = 9), preterm (n = 6), and had unilateral NRVT (n = 6). Six patients received thrombolysis and/or anticoagulation, and 4 patients received supportive care only. Two of the 6 patients treated with anticoagulation who had bilateral NRVT and anuria received thrombolysis with low-dose tissue plasminogen activator. Thrombolysis was not associated with any major adverse events, and both patients had marked improvement of renal function. Eight patients subsequently developed renal atrophy (3 received anticoagulation, 2 received thrombolysis with anticoagulation, and 3 received supportive care). Anticoagulation/thrombolysis did not appear to prevent renal atrophy. The role of thrombolysis needs to be further studied and considered in the setting of bilateral NRVT and acute renal failure.

  16. Coagulation inhibitors and activated protein C resistance in recurrent pregnancy losses in Indian women

    Directory of Open Access Journals (Sweden)

    P Lalita Jyotsna

    2011-01-01

    Full Text Available Background: Thrombophilias, both acquired and inherited, have been investigated in the etiopathogenesis of unexplained recurrent pregnancy loss. Aim: To study coagulation inhibitors and activated protein C resistance (APCR in recurrent pregnancy losses (RPL occurring in second and third trimesters. Materials and Methods: A total of 30 pregnant women (group A with two or more recurrent unexplained fetal loses were evaluated for APCR, protein C deficiency, protein S deficiency, antithrombin deficiency, and antiphospholipid antibodies (APLA. Thirty age-matched controls were taken (group B comprising of pregnant women with at least one live issue. Statistical Analysis: Comparisons between two group frequencies and group means were made using Chi square test and Student′s t test, respectively. Results: Protein C and protein S levels were reduced in group A compared with group B and the difference was statistically significant (P=0.005 and P=0.032, respectively. The mean value of antithrombin was slightly reduced in group A compared with group B. APCR was observed in 16.6% cases and 3.3% controls. However, the difference was not statistically significant. APLA was observed in 20% cases and none of the controls. Of these, lupus anticoagulant was positive in 16.6% cases and anticardiolipin antibodies in 10% cases. Combined defects were seen in seven patients. Conclusion: There is a significant risk of RPL in pregnant women with thrombophilias. Therefore, screening for thrombophilias may be justified in pregnant women with unexplained recurrent fetal wastage, especially in second and third trimester.

  17. Structure and anticoagulant properties of sulfated glycosaminoglycans from primitive Chordates

    Directory of Open Access Journals (Sweden)

    PAVÃO MAURO S. G.

    2002-01-01

    Full Text Available Dermatan sulfates and heparin, similar to the mammalian glycosaminoglycans, but with differences in the degree and position of sulfation were previously isolated from the body of the ascidian Styela plicata and Ascidia nigra. These differences produce profound effects on their anticoagulant properties. S. plicata dermatan sulfate composed by 2-O-sulfatedalpha-L-iduronic acid and 4-O-sulfated N-acetyl-beta-D-galactosamine residues is a potent anticoagulant due to a high heparin cofactor II activity. Surprisingly, it has a lower potency to prevent thrombus formation on an experimental model and a lower bleeding effect in rats than the mammalian dermatan sulfate. In contrast, A. nigra dermatan sulfate, also enriched in 2-O-sulfated alpha-L-iduronic acid, but in this case sulfated at O-6 of the N-acetyl-beta-D-galactosamine units, has no in vitro or in vivo anticoagulant activity, does not prevent thrombus formation but shows a bleeding effect similar to the mammalian glycosaminoglycan. Ascidian heparin, composed by 2-O-sulfated alpha-L-iduronic acid, N- and 6-O-sulfated glucosamine (75% and alpha-L-iduronic acid, N- and 6-O-sulfated glucosamine (25% disaccharide units has an anticoagulant activity 10 times lower than the mammalian heparin, is about 20 times less potent in the inhibition of thrombin by antithrombin, but has the same heparin cofactor II activity as mammalian heparin.

  18. Differential expression of cytochrome P450 genes between bromadiolone-resistant and anticoagulant-susceptible Norway rats:

    DEFF Research Database (Denmark)

    Markussen, Mette Drude; Heiberg, Ann-Charlotte; Fredholm, Merete;

    2008-01-01

    Anticoagulant resistance in Norway rats (Rattus norvegicus) has been suggested to be due to mutations in the VKORC1 gene, encoding the target protein of anticoagulant rodenticides such as warfarin and bromadiolone. Other factors, e.g. pharmacokinetics, may however also contribute to resistance. W...

  19. Differential expression of cytochrome P450 genes between bromadiolone-resistant and anticoagulant-susceptible Norway rats

    DEFF Research Database (Denmark)

    Markussen, Mette Drude Kjær; Heiberg, Ann-Charlotte; Fredholm, Merete;

    2008-01-01

    Background: Anticoagulant resistance in Norway rats, Rattus norvegicus (Berk.), has been suggested to be conferred by mutations in the VKORC1 gene, encoding the target protein of anticoagulant rodenticides. Other factors, e.g. pharmacokinetics, may also contribute to resistance, however. To examine...

  20. Transitions of care in anticoagulated patients

    Directory of Open Access Journals (Sweden)

    Michota F

    2013-06-01

    Full Text Available Franklin Michota Department of Hospital Medicine, Cleveland Clinic, Cleveland, OH, USA Abstract: Anticoagulation is an effective therapeutic means of reducing thrombotic risk in patients with various conditions, including atrial fibrillation, mechanical heart valves, and major surgery. By its nature, anticoagulation increases the risk of bleeding; this risk is particularly high during transitions of care. Established anticoagulants are not ideal, due to requirements for parenteral administration, narrow therapeutic indices, and/or a need for frequent therapeutic monitoring. The development of effective oral anticoagulants that are administered as a fixed dose, have low potential for drug-drug and drug-food interactions, do not require regular anticoagulation monitoring, and are suitable for both inpatient and outpatient use is to be welcomed. Three new oral anticoagulants, the direct thrombin inhibitor, dabigatran etexilate, and the factor Xa inhibitors, rivaroxaban and apixaban, have been approved in the US for reducing the risk of stroke and systemic embolism in patients with nonvalvular atrial fibrillation; rivaroxaban is also approved for prophylaxis and treatment of deep vein thrombosis, which may lead to pulmonary embolism in patients undergoing knee or hip replacement surgery. This review examines current options for anticoagulant therapy, with a focus on maintaining efficacy and safety during transitions of care. The characteristics of dabigatran etexilate, rivaroxaban, and apixaban are discussed in the context of traditional anticoagulant therapy. Keywords: hemorrhagic events, oral anticoagulation, parenteral anticoagulation, stroke, transitions of care

  1. The challenges of lupus anticoagulants.

    Science.gov (United States)

    Chighizola, Cecilia Beatrice; Raschi, Elena; Banzato, Alessandra; Borghi, Maria Orietta; Pengo, Vittorio; Meroni, Pier Luigi

    2016-01-01

    The term "lupus anticoagulant" (LA) refers to a heterogeneous group of immunoglobulins behaving as acquired in vitro inhibitors of coagulation. These antibodies, namely anti-β2GPI and anti-prothrombin antibodies, induce the in vitro elongation of clotting time interfering with phospholipid-dependent coagulation cofactors. Positive LA is associated with thrombosis and pregnancy complications, providing one of the three laboratory criteria for the classification of the anti-phospholipid syndrome. LA is the strongest predictor of clinical events, especially when associated with other anti-phospholipid antibodies. Much more controversial is the risk conveyed by isolated and weak LA. LA detection is technically laborious, envisaging screening, mixing and confirming tests. Hopefully critical issues in LA detection, such as the interference of anticoagulants, will be overcome, in the next future. PMID:26789237

  2. Synaptic vesicle proteins and active zone plasticity

    Directory of Open Access Journals (Sweden)

    Robert J Kittel

    2016-04-01

    Full Text Available Neurotransmitter is released from synaptic vesicles at the highly specialized presynaptic active zone. The complex molecular architecture of active zones mediates the speed, precision and plasticity of synaptic transmission. Importantly, structural and functional properties of active zones vary significantly, even for a given connection. Thus, there appear to be distinct active zone states, which fundamentally influence neuronal communication by controlling the positioning and release of synaptic vesicles. Vice versa, recent evidence has revealed that synaptic vesicle components also modulate organizational states of the active zone.The protein-rich cytomatrix at the active zone (CAZ provides a structural platform for molecular interactions guiding vesicle exocytosis. Studies in Drosophila have now demonstrated that the vesicle proteins Synaptotagmin-1 (Syt1 and Rab3 also regulate glutamate release by shaping differentiation of the CAZ ultrastructure. We review these unexpected findings and discuss mechanistic interpretations of the reciprocal relationship between synaptic vesicles and active zone states, which has heretofore received little attention.

  3. Anticoagulants used in plasma collection affect adipokine multiplexed measurements.

    Science.gov (United States)

    Allione, Alessandra; Di Gaetano, Cornelia; Dani, Nadia; Barberio, Davide; Sieri, Sabina; Krogh, Vittorio; Matullo, Giuseppe

    2016-04-01

    Obesity is an important health problem worldwide. Adipose tissue acts as an endocrine organ that secretes various bioactive substances, called adipokines, including pro-inflammatory biomarkers such as TNF-α, IL-6, leptin and C-reactive protein (CRP) and anti-inflammatory molecules such as adiponectin. The deregulated production of adipokines in obesity is linked to the pathogenesis of various disease processes and monitoring their variation is critical to understand metabolic diseases. The aim of this study was to determine the plasma concentration of adipokines in healthy subjects by multiplexed measurements and the effect of anticoagulants on their levels. Plasma samples from 10 healthy donors were collected in two different anticoagulants (sodium citrate or heparin). All markers, excluding TNF-α, showed significantly higher concentrations in heparinized compared to citrate plasma. However, levels of adipokines in different plasma samples were highly correlated for most of these markers. We reported that different anticoagulants used in the preparation of the plasma samples affected the measurements of some adipokines. The importance of the present results in epidemiology is relevant when comparing different studies in which blood samples were collected with different anticoagulants. PMID:26945995

  4. DNA-based control of protein activity.

    Science.gov (United States)

    Engelen, W; Janssen, B M G; Merkx, M

    2016-03-01

    DNA has emerged as a highly versatile construction material for nanometer-sized structures and sophisticated molecular machines and circuits. The successful application of nucleic acid based systems greatly relies on their ability to autonomously sense and act on their environment. In this feature article, the development of DNA-based strategies to dynamically control protein activity via oligonucleotide triggers is discussed. Depending on the desired application, protein activity can be controlled by directly conjugating them to an oligonucleotide handle, or expressing them as a fusion protein with DNA binding motifs. To control proteins without modifying them chemically or genetically, multivalent ligands and aptamers that reversibly inhibit their function provide valuable tools to regulate proteins in a noncovalent manner. The goal of this feature article is to give an overview of strategies developed to control protein activity via oligonucleotide-based triggers, as well as hurdles yet to be taken to obtain fully autonomous systems that interrogate, process and act on their environments by means of DNA-based protein control. PMID:26812623

  5. Modulation of mitogen-activated protein kinase-activated protein kinase 3 by hepatitis C virus core protein

    DEFF Research Database (Denmark)

    Ngo, HT; Pham, Long; Kim, JW;

    2013-01-01

    Hepatitis C virus (HCV) is highly dependent on cellular proteins for its own propagation. In order to identify the cellular factors involved in HCV propagation, we performed protein microarray assays using the HCV core protein as a probe. Of ~9,000 host proteins immobilized in a microarray......, approximately 100 cellular proteins were identified as HCV core-interacting partners. Of these candidates, mitogen-activated protein kinase-activated protein kinase 3 (MAPKAPK3) was selected for further characterization. MAPKAPK3 is a serine/threonine protein kinase that is activated by stress and growth...... inducers. Binding of HCV core to MAPKAPK3 was confirmed by in vitro pulldown assay and further verified by coimmunoprecipitation assay. HCV core protein interacted with MAPKAPK3 through amino acid residues 41 to 75 of core and the N-terminal half of kinase domain of MAPKAPK3. In addition, both RNA...

  6. New Type of Oral Anticoagulants

    Institute of Scientific and Technical Information of China (English)

    刘泽霖

    2012-01-01

    Since 1960,so far,has half a century,long-term oral vitamin K antagonists (VKA) for anticoagulation main plan,but the shortcomings of the VKA but not allow to ignore:( 1 ) the VKA effect to be slow,VKA after diagnosis should be immediate treatment,this plan have to start with unfractionated heparin (UFH),low molecular weight heparin (LMWH) and fondaparinux injection,use 5 ~ 10 d transition again after oral VKA,this plan for outpatient greatly inconvenience;(2) in the use of heparin drugs there is also monitoring problem during or the occurrence of heparin induction thrombocytopenic thrombosis disease (HITT) risk;(3) VKA treatment vulnerable to food,drugs,to VKA considerations of the interference of the individual differences are of great reaction;(4)VKA treatment window,need to narrow in close monitoring of adjusting dosage benefits under,but the present survey indicates that at least a third of patients with clinically failed to control the INR within the scope of the treatment.So send development new anticoagulants,especially oral anticoagulants listed was imminent

  7. Pro- and anticoagulant properties of factor V in pathogenesis of thrombosis and bleeding disorders.

    Science.gov (United States)

    Dahlbäck, Björn

    2016-05-01

    Factor V (FV) serves an important role in the regulation of blood coagulation, having both pro- and anticoagulant properties. The circulating high molecular weight single-chain FV molecule undergoes a series of proteolytic cleavages during both activation of coagulation and during anticoagulant regulation of coagulation by activated protein C (APC). It is noteworthy that mutations in the factor V gene (F5) either cause thrombosis or bleeding. New insights into the importance and complexity of FV functions have been generated from elucidation of the pathogenic mechanisms of two familial mutations in the F5 gene. The first mutation was identified as a result of the discovery of APC resistance as the most common risk factor for venous thrombosis. The mutation (FV Leiden) predicts the Arg(506) Gln replacement, which impairs the normal regulation of FVa by APC, as the Arg506 site is an important APC cleavage site. In addition, elucidation of APC resistance resulted in the discovery of the anticoagulant APC cofactor activity of FV. The second FV mutation (FV(A2440G) ), identified in a family with an autosomal dominant bleeding disorder, has led to the discovery of an alternative splicing generating a previously unidentified FV isoform (FV-Short), which inhibits coagulation via an unexpected and intriguing mechanism involving the coagulation inhibitor TFPI-α. These are naturally occurring mutations in the F5 gene that have generated new knowledge on the role of FV in regulation of coagulation and the importance of genetic risk factors for thrombosis and bleeding. PMID:27161771

  8. Effect of magnetic bracelets on the coagulation and anticoagulation systems of the blood of patients with hypertension

    Science.gov (United States)

    Bublis, V. V.; Zabrodina, L. V.; Platonova, A. T.; Meyerova, Y. A.

    1974-01-01

    The data which have been obtained on the influence of magnetic bracelets on the coagulation and anticoagulation systems of the blood indicate that the wearing of magnetic bracelets results in a decrease in the coagulation activity of the blood and an increase in the activity of the anticoagulation system. These changes must be viewed as favorable for patients with cardiovascular pathology.

  9. Anticoagulant factor V: factors affecting the integration of novel scientific discoveries into the broader framework.

    Science.gov (United States)

    LaBonte, Michelle L

    2014-09-01

    Since its initial discovery in the 1940s, factor V has long been viewed as an important procoagulant protein in the coagulation cascade. However, in the later part of the 20th century, two different scientists proposed novel anticoagulant roles for factor V. Philip Majerus proposed the first anticoagulant function for factor V in 1983, yet ultimately it was not widely accepted by the broader scientific community. In contrast, Björn Dahlbäck proposed a different anticoagulant role for factor V in 1994. While this role was initially contested, it was ultimately accepted and integrated into the scientific framework. In this paper, I present a detailed historical account of these two anticoagulant discoveries and propose three key reasons why Dahlbäck's anticoagulant role for factor V was accepted whereas Majerus' proposed role was largely overlooked. Perhaps most importantly, Dahlbäck's proposed anticoagulant role was of great clinical interest because the discovery involved the study of an important subset of patients with thrombophilia. Soon after Dahlbäck's 1994 work, this patient population was shown to possess the factor V Leiden mutation. Also key in the ultimate acceptance of the second proposed anticoagulant role was the persistence of the scientist who made the discovery and the interest in and ability of others to replicate and reinforce this work. This analysis of two different yet similar discoveries sheds light on factors that play an important role in how new discoveries are incorporated into the existing scientific framework. PMID:24853975

  10. New oral anticoagulants: key messages for clinicians

    Directory of Open Access Journals (Sweden)

    Matteo Giorgi-Pierfranceschi

    2013-12-01

    Full Text Available New oral anticoagulants are an effective and safe alternative to vitamin K antagonists in many fields of clinical practice. The use of the direct inhibitors of activated Factor II (dabigatran and activated Factor X (apixaban and rivaroxaban, both in patients with non-valvular atrial fibrillation (NVAF and those with acute venous thromboembolism (VTE, is of great interest for internal medicine physicians. This paper aims to give practical guidance on management (starting therapy, follow up and bleeding complications of patients treated with dabigatran, rivaroxaban or apixaban for NVAF or acute VTE providing practical tables concerning the phases of therapy, management of complications, drug interaction and dose adjustment if renal impairment occurs.

  11. Direct oral anticoagulants and venous thromboembolism

    Directory of Open Access Journals (Sweden)

    Massimo Franchini

    2016-09-01

    Full Text Available Venous thromboembolism (VTE, consisting of deep vein thrombosis and pulmonary embolism, is a major clinical concern associated with significant morbidity and mortality. The cornerstone of management of VTE is anticoagulation, and traditional anticoagulants include parenteral heparins and oral vitamin K antagonists. Recently, new oral anticoagulant drugs have been developed and licensed, including direct factor Xa inhibitors (e.g. rivaroxaban, apixaban and edoxaban and thrombin inhibitors (e.g. dabigatran etexilate. This narrative review focusses on the characteristics of these direct anticoagulants and the main results of published clinical studies on their use in the prevention and treatment of VTE.

  12. Activated protein C modulates the proinflammatory activity of dendritic cells

    Directory of Open Access Journals (Sweden)

    Matsumoto T

    2015-05-01

    Full Text Available Takahiro Matsumoto,1,2* Yuki Matsushima,1* Masaaki Toda,1 Ziaurahman Roeen,1 Corina N D'Alessandro-Gabazza,1,5 Josephine A Hinneh,1 Etsuko Harada,1,3 Taro Yasuma,4 Yutaka Yano,4 Masahito Urawa,1,5 Tetsu Kobayashi,5 Osamu Taguchi,5 Esteban C Gabazza1 1Department of Immunology, Mie University Graduate School of Medicine, Tsu, Mie Prefecture, 2BONAC Corporation, BIO Factory 4F, Fukuoka, 3Iwade Research Institute of Mycology, 4Department of Endocrinology, Diabetes and Metabolism, 5Department of Pulmonary and Critical Care Medicine, Mie University Graduate School of Medicine, Tsu, Mie Prefecture, Japan *These authors contributed equally to this work Background: Previous studies have demonstrated the beneficial activity of activated protein C in allergic diseases including bronchial asthma and rhinitis. However, the exact mechanism of action of activated protein C in allergies is unclear. In this study, we hypothesized that pharmacological doses of activated protein C can modulate allergic inflammation by inhibiting dendritic cells. Materials and methods: Dendritic cells were prepared using murine bone marrow progenitor cells and human peripheral monocytes. Bronchial asthma was induced in mice that received intratracheal instillation of ovalbumin-pulsed dendritic cells. Results: Activated protein C significantly increased the differentiation of tolerogenic plasmacytoid dendritic cells and the secretion of type I interferons, but it significantly reduced lipopolysaccharide-mediated maturation and the secretion of inflammatory cytokines in myeloid dendritic cells. Activated protein C also inhibited maturation and the secretion of inflammatory cytokines in monocyte-derived dendritic cells. Activated protein C-treated dendritic cells were less effective when differentiating naïve CD4 T-cells from Th1 or Th2 cells, and the cellular effect of activated protein C was mediated by its receptors. Mice that received adoptive transfer of activated protein C

  13. Management of anticoagulation and antiplatelet therapy in patients with left ventricular assist devices.

    Science.gov (United States)

    Baumann Kreuziger, Lisa M

    2015-04-01

    Left ventricular assist devices (LVADs) have increased the survival of patients with advanced heart failure fourfold. Despite these advances, significant bleeding and thrombotic complications occur. Hemorrhage requiring surgery has been reported in up to 30% of adults and 50% of children after LVAD placement. LVAD thrombosis and embolic stroke lead to significant long-term morbidity. Adults are treated with antithrombotic therapy to prevent thrombotic complications, but the amount and intensity of treatment differs between institutions. The goal international normalized ratio for warfarin therapy varies from 1.5 to 3.0. Some physicians manage adult LVAD patients without antiplatelet medication, whereas other adults are treated with aspirin as a single agent or combined with dipyridamole. In contrast, physicians typically manage children with LVADs using the Edmonton Anticoagulation and Platelet Inhibition Protocol, a detailed algorithm for anticoagulation and antiplatelet treatment modified based on thromboelastography results. LVAD implantation causes consumption of coagulation proteins, activation of fibrinolysis, and loss of high molecular weight von Willebrand protein multimers. How these changes in the coagulation system influence the risk of hemorrhage and initiation of thrombosis is unknown. Prospective, controlled studies are needed to determine the antithrombotic regimen that most effectively balances bleeding and thrombosis in LVAD patients. PMID:25549823

  14. Anticoagulant Medicine: Potential for Drug-Food Interactions

    Science.gov (United States)

    ... AerobiKa® Cardiology Medications Anticoagulant Medicine Anticoagulants and Drug-Food Interactions COPD Medications Bronchodilators Anti-Inflammatories Antibiotics Managing Your Medications Devices ...

  15. Multicomponent determination of 4-hydroxycoumarin anticoagulant rodenticides in blood serum by liquid chromatography with fluorescence detection.

    Science.gov (United States)

    Felice, L J; Chalermchaikit, T; Murphy, M J

    1991-01-01

    A sensitive liquid chromatographic method was developed for the analysis of 4-hydroxycoumarin anticoagulant rodenticides in blood serum. The method can simultaneously measure the serum levels of five anticoagulant rodenticides: brodifacoum, bromadiolone, coumatetralyl, difenacoum, and warfarin. Serum proteins are precipitated with acetonitrile and the supernatant is mixed with ethyl ether. The organic phase is separated, evaporated to dryness, and the residue subjected to chromatographic analysis. The anticoagulants are separated by reversed-phase gradient chromatography with fluorescence detection at an excitation wavelength of 318 nm and emission wavelength of 390 nm. Extraction efficiencies of 68.1 to 98.2% were obtained. The within-run precision (CV) ranged from 2.19 to 3.79% and the between-run precision (CV) from 3.72 to 9.57%. The anticoagulants can be quantitated at serum levels of 10 to 20 ng/mL. PMID:1943055

  16. [New oral anticoagulants - influence on coagulation tests].

    Science.gov (United States)

    Simeon, L; Nagler, M; Wuillemin, W A

    2014-01-01

    The new oral anticoagulants (NOACs) represent alternative antithrombotic agents for prophylaxis and therapy of thromboembolic diseases. They act either by inhibition of the clotting factor Xa or IIa (thrombin). As a consequence, they influence several coagulation assays (for example prothrombin time, activated partial thromboplastin time). Because of the short half-life of these new agents, these changes show great variations in the course of 24 hours. Furthermore, there are significant differences of laboratory results depending on the used reagents. We explain the influence of apixaban, rivaroxaban (factor Xa inhibitors) and dabigatran (thrombin inhibitor) on the most commonly used coagulation assays. Besides we show that this influence depends on the way of action of the drug as well as on the principle of the coagulation assay. Being aware of this relationships helps to interpret the results of coagulation assays under influence of NOACs correctly.

  17. Anticoagulant, antiplatelet and antianemic effects of Punica granatum (pomegranate) juice in rabbits.

    Science.gov (United States)

    Riaz, Azra; Khan, Rafeeq A

    2016-04-01

    Pomegranate (Punica granatum L., Punicaceae) is a good source of minerals and phytochemicals with diverse pharmacological activities such as anxiolytic, antidepressant, hypoglycemic, hypolipidemic, and anti-inflammatory activities. Effects of P. granatum on blood parameters and coagulation have, however, been little studied. The aim of the study was to assess the outcome of P. granatum on coagulation and anticoagulation factors at different doses on blood samples of healthy white rabbits. Blood samples of the animals were collected twice during the study and biochemical assays were performed to assess the effect on hematological, coagulation, anticoagulation, and platelet aggregation. Significant changes were observed in erythrocytes, hemoglobin, and mean corpuscular hemoglobin concentration, while bleeding and thrombin time were also prolonged significantly. There was significant increase in protein C, thrombin antithrombin complex levels, and decrease in platelet aggregation and fibrinogen concentration, in a dose-dependent manner. The results of hematological and coagulation assays lead to the speculation about a possible antianemic and cardioprotective effect of P. granatum. PMID:26881853

  18. Human Monoclonal Antiphospholipid Antibodies Disrupt the Annexin A5 Anticoagulant Crystal Shield on Phospholipid Bilayers

    Science.gov (United States)

    Rand, Jacob H.; Wu, Xiao-Xuan; Quinn, Anthony S.; Chen, Pojen P.; McCrae, Keith R.; Bovill, Edwin G.; Taatjes, Douglas J.

    2003-01-01

    The antiphospholipid (aPL) syndrome is an autoimmune condition that is marked by recurrent pregnancy losses and/or systemic vascular thrombosis in patients who have antibodies against phospholipid/co-factor complexes. The mechanism(s) for pregnancy losses and thrombosis in this condition is (are) not known. Annexin A5 is a potent anticoagulantprotein, expressed by placental trophoblasts and endothelial cells, that crystallizes over anionic phospholipids, shielding them from availability for coagulation reactions. We previously presented data supporting the hypothesis that aPL antibody-mediated disruption of the anticoagulant annexin A5 shield could be a thrombogenic mechanism in the aPL syndrome. However, this has remained a subject of controversy. We therefore used atomic force microscopy, a method previously used to study the crystallization of annexin A5, to image the effects of monoclonal human aPL antibodies on the crystal structure of the protein over phospholipid bilayers. In the presence of the aPL monoclonal antibodies (mAbs) and β2-GPI, the major aPL co-factor, structures presumed to be aPL mAb-antigen complexes were associated with varying degrees of disruption to the annexin A5 crystallization pattern over the bilayer. In addition, measurements of prothrombinase activity on the phospholipid bilayers showed that the aPL mAbs reduced the anti-coagulant effect of annexin A5 and promoted thrombin generation. These data provide morphological evidence that support the hypothesis that aPL antibodies can disrupt annexin A5 binding to phospholipid membranes and permit increased generation of thrombin. The aPL antibody-mediated disruption of the annexin A5 anticoagulant shield may be an important prothrombotic mechanism in the aPL syndrome. PMID:12937161

  19. Activation and activities of the p53 tumour suppressor protein

    OpenAIRE

    Bálint, É; Vousden, K H

    2001-01-01

    The p53 tumour suppressor protein inhibits malignant progression by mediating cell cycle arrest, apoptosis or repair following cellular stress. One of the major regulators of p53 function is the MDM2 protein, and multiple forms of cellular stress activate p53 by inhibiting the MDM2-mediated degradation of p53. Mutations in p53, or disruption of the pathways that allow activation of p53, seem to be a general feature of all cancers. Here we review recent advances in our understanding of the pat...

  20. Tailoring the surface properties of polypropylene films through cold atmospheric pressure plasma (CAPP) assisted polymerization and immobilization of biomolecules for enhancement of anti-coagulation activity

    Science.gov (United States)

    Navaneetha Pandiyaraj, K.; Ram Kumar, M. C.; Arun Kumar, A.; Padmanabhan, P. V. A.; Deshmukh, R. R.; Bah, M.; Ismat Shah, S.; Su, Pi-Guey; Halleluyah, M.; Halim, A. S.

    2016-05-01

    Enhancement of anti-thrombogenic properties of polypropylene (PP) to avert the adsorption of plasma proteins (fibrinogen and albumin), adhesion and activation of the platelets are very important for vast biomedical applications. The cold atmospheric pressure plasma (CAPP) assisted polymerization has potential to create the specific functional groups such as Osbnd Cdbnd O, Cdbnd O, Csbnd N and Ssbnd S. on the surface of polymeric films using selective precursor in vapour phase to enhance anti-thrombogenic properties. Such functionalized polymeric surfaces would be suitable for various biomedical applications especially to improve the blood compatibility. The eventual aspiration of the present investigation is to develop the biofunctional coating onto the surface of PP films using acrylic acid (AAc) and polyethylene glycol (PEG) as a precursor in a vapour phase by incorporating specific functional groups for immobilization of biomolecules such as heparin (HEP), chitosan (CHI) and insulin (INS) on the surface of plasma modified PP films. The surface properties such as hydrophilicity, chemical composition, surface topography of the surface modified PP films were analyzed by contact angle (CA), Fourier transform infrared spectroscopy (FTIR), X-ray photo electron spectroscopy (XPS) and atomic force microscopy (AFM). Furthermore the anti-thrombogenic properties of the surface modified PP films were studied by in vitro tests which include platelet adhesion and protein adsorption analysis. It was found that the anti-thrombogenic properties of the PP films are effectively controlled by the CAPP grafting of AAc and PEG followed by immobilization of biomolecules of heparin, chitosan and insulin. The grafting and immobilization was confirmed by FTIR and XPS through the recognition of specific functional groups such as COOH, Csbnd O, Ssbnd S and Csbnd N. on the surface of PP film. Furthermore, the surface morphology and hydrophilic nature of the PP films also tailored

  1. Anticoagulants

    Science.gov (United States)

    ... even if it is not listed below. Aspirin Acetaminophen (e.g., Tylenol, Excedrin) Ibuprofen (e.g., Motrin, ... skin or eyes (jaundice) Rare side effects: Headache Dizziness Shortness of breath Mouth sores or bleeding gums ...

  2. Total Cellular RNA Modulates Protein Activity.

    Science.gov (United States)

    Majumder, Subhabrata; DeMott, Christopher M; Reverdatto, Sergey; Burz, David S; Shekhtman, Alexander

    2016-08-16

    RNA constitutes up to 20% of a cell's dry weight, corresponding to ∼20 mg/mL. This high concentration of RNA facilitates low-affinity protein-RNA quinary interactions, which may play an important role in facilitating and regulating biological processes. In the yeast Pichia pastoris, the level of ubiquitin-RNA colocalization increases when cells are grown in the presence of dextrose and methanol instead of methanol as the sole carbon source. Total RNA isolated from cells grown in methanol increases β-galactosidase activity relative to that seen with RNA isolated from cells grown in the presence of dextrose and methanol. Because the total cellular RNA content changes with growth medium, protein-RNA quinary interactions can alter in-cell protein biochemistry and may play an important role in cell adaptation, critical to many physiological and pathological states. PMID:27456029

  3. Raman optical activity of proteins and glycoproteins

    Energy Technology Data Exchange (ETDEWEB)

    Smyth, E

    2000-03-01

    Raman optical activity (ROA), measured in this project as a small difference in the intensity of Raman scattering from chiral molecules in right- and left-circularly polarised incident laser light, offers the potential to provide more information about the structure of biological molecules in aqueous solution than conventional spectroscopic techniques. Chapter one contains a general discussion of the relative merits of different spectroscopic techniques for structure determination of biomolecules, as well as a brief introduction to ROA. In Chapter two a theoretical analysis of ROA is developed, which extends the discussion in chapter one. The spectrometer setup and sample preparation is then discussed in chapter three. Instrument and sample conditions are monitored to ensure that the best results are obtained. As with any experimental project problems occur, which may result in a degradation of the spectra obtained. The cause of these problems was explored and remedied whenever possible. Chapter four introduces a brief account of protein, glycoprotein and carbohydrate structure and function, with a particular emphasis on the structure of proteins. In the remaining chapters experimental ROA results on proteins and glycoproteins, with some carbohydrate samples, from a wide range of sources are examined. For example, in chapter five some {beta}-sheet proteins are examined. Structural features in these proteins are examined in the extended amide III region of their ROA spectra, revealing that ROA is sensitive to the rigidity or flexibility inherent in proteins. Chapter six concentrates on a group of proteins (usually glycoproteins) known as the serine proteinase inhibitors (serpins). Medically, the serpins are one of the most important groups of proteins of current interest, with wide-ranging implications in conditions such as Down's syndrome, Alzheimer's disease, and emphysema with associated cirrhosis of the liver. With favourable samples and conditions ROA

  4. Mitogen-activated protein kinases in atherosclerosis

    Directory of Open Access Journals (Sweden)

    Dorota Bryk

    2014-01-01

    Full Text Available Intracellular signalling cascades, in which MAPK (mitogen-activated protein kinases intermediate, are responsible for a biological response of a cell to an external stimulus. MAP kinases, which include ERK1/2 (extracellular signalling-regulated kinase, JNK (c-Jun N-terminal kinase and p 38 MAPK, regulate the activity of many proteins, enzymes and transcription factors and thus have a wide spectrum of biological effects. Many basic scientific studies have defined numerous details of their pathway organization and activation. There are also more and more studies suggesting that individual MAP kinases probably play an important role in the pathogenesis of atherosclerosis. They may mediate inflammatory processes, endothelial cell activation, monocyte/macrophage recruitment and activation, smooth muscle cell proliferation and T-lymphocyte differentiation, all of which represent crucial mechanisms involved in pathogenesis of atherosclerosis. The specific inhibition of an activity of the respective MAP kinases may prove a new therapeutic approach to attenuate atherosclerotic plaque formation in the future. In this paper, we review the current state of knowledge concerning MAP kinase-dependent cellular and molecular mechanisms underlying atherosclerosis.

  5. Synthesis, anticoagulant and PIVKA-II induced by new 4-hydroxycoumarin derivatives.

    Science.gov (United States)

    Abdelhafez, Omaima M; Amin, Kamelia M; Batran, Rasha Z; Maher, Timothy J; Nada, Somaia A; Sethumadhavan, Shalini

    2010-05-15

    The action of the coumarin-type drugs and related compounds is reviewed to their VKOR antagonistic effects. In our study, twenty 3-pyridinyl, pyrimidinyl and pyrazolyl-4-hydroxycoumarin derivatives were synthesized. A comparative in vivo (CT, PT determination) and in vitro (measurement of PIVKA-II levels) anticoagulant study with respect to warfarin showed that the synthesized compounds have different anticoagulant activities, the most prospective compounds were the 3-pyrazolyl-4-hydroxycoumarin derivatives.

  6. Synaptic Vesicle Proteins and Active Zone Plasticity.

    Science.gov (United States)

    Kittel, Robert J; Heckmann, Manfred

    2016-01-01

    Neurotransmitter is released from synaptic vesicles at the highly specialized presynaptic active zone (AZ). The complex molecular architecture of AZs mediates the speed, precision and plasticity of synaptic transmission. Importantly, structural and functional properties of AZs vary significantly, even for a given connection. Thus, there appear to be distinct AZ states, which fundamentally influence neuronal communication by controlling the positioning and release of synaptic vesicles. Vice versa, recent evidence has revealed that synaptic vesicle components also modulate organizational states of the AZ. The protein-rich cytomatrix at the active zone (CAZ) provides a structural platform for molecular interactions guiding vesicle exocytosis. Studies in Drosophila have now demonstrated that the vesicle proteins Synaptotagmin-1 (Syt1) and Rab3 also regulate glutamate release by shaping differentiation of the CAZ ultrastructure. We review these unexpected findings and discuss mechanistic interpretations of the reciprocal relationship between synaptic vesicles and AZ states, which has heretofore received little attention.

  7. Compatibility of Injectable Anticoagulant Agents in Ethanol; In Vitro Antibiofilm Activity and Impact on Polyurethane Catheters of Enoxaparin 400 U/mL in 40% v/v Ethanol.

    Directory of Open Access Journals (Sweden)

    Damien Balestrino

    Full Text Available Interdialytic lock solutions should maintain catheter patency and prevent catheter infections. We aimed to determine in which conditions injectable anticoagulant agents (IAAs combined with ethanol are compatible and to assess the antibiofilm activity of the selected combination and its effects on dialysis catheters (DC.The solubility and compatibility of unfractionated heparin (UFH, low molecular weight heparins (LMWHs, heparinoids and fondaparinux (50 to 2,500 U/mL in 30 to 70% ethanol were determined by visual observation. The stability of enoxaparin in ethanol and the ethanol content were assessed by high performance liquid chromatography (HPLC and titrimetric control, respectively. The bactericidal effect was determined on 24h-old biofilms embedded in silicone-DC. The integrity of polyurethane-DC immersed in anticoagulant-ethanol was assessed by gas chromatography-mass spectrometry (GC-MS and compared with previously published results.The compatibility of IAAs and ethanol varied according to IAA type and concentration, and ethanol content. UFH in 40% ethanol was not compatible, whatever the UFH concentration used. Established limits of compatibility of enoxaparin, nadroparin, dalteparin and tinzaparin in 40% ethanol were 1350, 575, 307 and 207 U/ml, respectively, and up to 300 U/ml for danaparoid and 1 mg/mL for fondaparinux. Enoxaparin 400 U/mL in 40% ethanol (Enox/Eth eradicated biofilm after 4 hours of exposure for Staphylococcus epidermidis, Pseudomonas aeruginosa and Candida albicans and after 24 hours for Klebsiella pneumoniae and S. aureus. Aliphatic carbonate and alcohol compounds were released by polyurethane-DC after Enox/Eth exposure, as after 40% ethanol or saline exposure. There was no significant difference between the amounts released after 30 minutes of exposure to Enox/Eth and 15 days to saline.A 40% ethanol solution can be combined with all IAAs but UFH. Enox/Eth was effective as an anti-biofilm agent with minor impacts on

  8. Compatibility of Injectable Anticoagulant Agents in Ethanol; In Vitro Antibiofilm Activity and Impact on Polyurethane Catheters of Enoxaparin 400 U/mL in 40% v/v Ethanol

    Science.gov (United States)

    Charbonnel, Nicolas; Forestier, Christiane; Lartigue, Claire; Souweine, Bertrand

    2016-01-01

    Background and Objectives Interdialytic lock solutions should maintain catheter patency and prevent catheter infections. We aimed to determine in which conditions injectable anticoagulant agents (IAAs) combined with ethanol are compatible and to assess the antibiofilm activity of the selected combination and its effects on dialysis catheters (DC). Methods The solubility and compatibility of unfractionated heparin (UFH), low molecular weight heparins (LMWHs), heparinoids and fondaparinux (50 to 2,500 U/mL) in 30 to 70% ethanol were determined by visual observation. The stability of enoxaparin in ethanol and the ethanol content were assessed by high performance liquid chromatography (HPLC) and titrimetric control, respectively. The bactericidal effect was determined on 24h-old biofilms embedded in silicone-DC. The integrity of polyurethane-DC immersed in anticoagulant-ethanol was assessed by gas chromatography-mass spectrometry (GC-MS) and compared with previously published results. Results The compatibility of IAAs and ethanol varied according to IAA type and concentration, and ethanol content. UFH in 40% ethanol was not compatible, whatever the UFH concentration used. Established limits of compatibility of enoxaparin, nadroparin, dalteparin and tinzaparin in 40% ethanol were 1350, 575, 307 and 207 U/ml, respectively, and up to 300 U/ml for danaparoid and 1 mg/mL for fondaparinux. Enoxaparin 400 U/mL in 40% ethanol (Enox/Eth) eradicated biofilm after 4 hours of exposure for Staphylococcus epidermidis, Pseudomonas aeruginosa and Candida albicans and after 24 hours for Klebsiella pneumoniae and S. aureus. Aliphatic carbonate and alcohol compounds were released by polyurethane-DC after Enox/Eth exposure, as after 40% ethanol or saline exposure. There was no significant difference between the amounts released after 30 minutes of exposure to Enox/Eth and 15 days to saline. Conclusions A 40% ethanol solution can be combined with all IAAs but UFH. Enox/Eth was effective as

  9. The Anticoagulation Effects of Glycosaminoglycan from Mactra veneriformis

    Directory of Open Access Journals (Sweden)

    Yue Wang

    2015-07-01

    Full Text Available In this study, the anticoagulation effect of glycosaminoglycan from Mactra veneriformis was studied. The results showed that glycosaminoglycan mainly exerted anticoagulation via antithrombin III. Glycosaminoglycan could passivate the function of heparin cofactor II inhibiting thrombin activity. Glycosaminoglycan significantly reduced the activities of coagulation factor II, V, VII, X, VIII, IX, XI, XII as well as fibrinogen content in the plasma (p<0.05, p<0.01. Besides, glycosaminoglycan could extend blood recalcification time in rats by shielding Ca2+ in plasma and significantly reduced Ca2+ concentration in rats and mice serum (p<0.05, p<0.01. Glycosaminoglycan reduced the Ca2+ concentration in serum in a more intensive way than that of heparin sodium (p<0.05, p<0.01.

  10. Momordica charantia seed extract exhibits strong anticoagulant effect by specifically interfering in intrinsic pathway of blood coagulation and dissolves fibrin clot.

    Science.gov (United States)

    Manjappa, Bhagyalakshmi; Gangaraju, Sowmyashree; Girish, Kesturu S; Kemparaju, Kempaiah; Gonchigar, Sathish J; Shankar, Rohit L; Shinde, Manohar; Sannaningaiah, Devaraja

    2015-03-01

    The current study explores the anticoagulant and fibrin clot-hydrolyzing properties of Momordica charantia seed extract (MCSE). MCSE hydrolyzed casein with the specific activity of 0.780 units/mg per min. Interestingly, it enhanced the clot formation process of citrated human plasma from control 146 to 432 s. In addition, the intravenous injection of MCSE significantly prolonged the bleeding time in a dose-dependent manner from control 150 to more than 800 s, and strengthened its anticoagulant activity. Interestingly, MCSE specifically prolonged the clotting time of only activated partial thromboplastin time, but not prothrombin time, and revealed the participation of MCSE in the intrinsic pathway of the blood coagulation cascade. Furthermore, MCSE completely hydrolyzed both Aα and Bβ chains of the human fibrinogen and partially hydrolyzed the γ chain. However, it hydrolyzed all the chains (α polymer, α chain, β chain and γ-γ dimmers) of partially cross-linked human fibrin clot. The proteolytic activity followed by the anticoagulant effect of the MCSE was completely abolished by the 1,10-phenanthroline and phenyl methyl sulphonyl fluoride, but iodoacetic acid, EDTA, and ethylene glycol-N,N,N',N'-tetra acetic acid did not. Curiously, MCSE did not hydrolyze any other plasma proteins except the plasma fibrinogen. Moreover, MCSE was devoid of RBC lysis, edema and hemorrhagic properties, suggesting its nontoxic nature. Taken together, MCSE may be a valuable candidate in the treatment of blood clot/thrombotic disorders. PMID:25192240

  11. 仙人掌多糖结构分析及抗凝血活性研究(英文)%Structural Analysis and Anticoagulant Activity of Polysaccharides from Opuntia milpa alta

    Institute of Scientific and Technical Information of China (English)

    蔡为荣; 谢亮亮; 陶鹏飞; 崔武卫

    2012-01-01

    [Objective] To analyze the components and structure of Opuntia milpa alta polysaccharides, and to study its anticoagulant activity. [Method] The crude polysaccharides (CP) were prepared from Opuntia milpa alta using hot water extraction and ethanol precipitation method, purified by anion-exchange chromatography and gel filtration chromatography to study its monosaccharide composition, weight-average molecular weight distribution and main chain structure. And a preliminary study was conducted on the anticoagulant activity of polysaccharide components. [Result] The polysaccharide components WSP1, WSP2a and WSP3 were obtained from CP by the anion-exchange chromatography and gel filtration chromatography. WSP1 was mainly composed of galactose with a weight-average molecular weight of 2.32×106. WSP2a consisted of rhamnose, arabinose, xylose, mannose, glucose, galactose, glucuronic acid and galacturonic acid, the contents were 6.3%, 32.3%, 12.9%, 1.5%, 4.8%, 37.1%, 0.64% and 4.4%, respectively. WSP3 mainly composed of arabinose, xylose, rhamnose and trace of glucose, mannose, uronic acid. The weight-average molecular weight of WSP2a and WSP3 was 1.24×106 and 7.92×106, respectively. WSP2 prolonged the activated partial thromboplatin time (APTT) and thrombin time (TT), while had no significant effect on the prothrombin time (PT) in vitro, indicating that anticoagulant activity of WSP2 functions by affecting the intrinsic coagulation system. The test of inhibition to the conversion of fibrinogen into thrombin showed that WSP2a and WSP3 had obvious anticoagulant activity. Methylation analysis indicated that the main chain of WSP2a was constituted of 1, 4-GalA, 1, 2-Rha and 1, 2, 4-Rha. [Conclusion] This study provided experimental basis for the optimization and development of polysaccharide resources from cactus%[目的]分析仙人掌多糖组分和结构,并研究其抗凝血活性。[方法]以米邦塔仙人掌为试验材料,通过热水浸提、醇

  12. Chitosan-based ultrathin films as antifouling, anticoagulant and antibacterial protective coatings.

    Science.gov (United States)

    Bulwan, Maria; Wójcik, Kinga; Zapotoczny, Szczepan; Nowakowska, Maria

    2012-01-01

    Ultrathin antifouling and antibacterial protective nanocoatings were prepared from ionic derivatives of chitosan using layer-by-layer deposition methodology. The surfaces of silicon, and glass protected by these nanocoatings were resistant to non-specific adsorption of proteins disregarding their net charges at physiological conditions (positively charged TGF-β1 growth factor and negatively charged bovine serum albumin) as well as human plasma components. The coatings also preserved surfaces from the formation of bacterial (Staphylococcus aureus) biofilm as shown using microscopic studies (SEM, AFM) and the MTT viability test. Moreover, the chitosan-based films adsorbed onto glass surface demonstrated the anticoagulant activity towards the human blood. The antifouling and antibacterial actions of the coatings were correlated with their physicochemical properties. The studied biologically relevant properties were also found to be dependent on the thickness of those nanocoatings. These materials are promising for biomedical applications, e.g., as protective coatings for medical devices, anticoagulant coatings and protective layers in membranes. PMID:21967904

  13. Bleeding Risk, Management and Outcome in Patients Receiving Non-VKA Oral Anticoagulants (NOACs).

    Science.gov (United States)

    Werth, Sebastian; Breslin, Tomás; NiAinle, Fionnuala; Beyer-Westendorf, Jan

    2015-08-01

    Modern direct-acting anticoagulants are rapidly replacing vitamin K antagonists (VKA) in the management of millions of patients worldwide who require anticoagulation. These drugs include agents that inhibit activated factor X (FXa) (such as apixaban and rivaroxaban) or thrombin (such as dabigatran), and are collectively known today as non-VKA oral anticoagulants (NOACs). Since bleeding is the most common and most dangerous side effect of long-term anticoagulation, and because NOACs have very different mechanisms of action and pharmacokinetics compared with VKA, physicians are naturally concerned about the lack of experience regarding frequency, management and outcome of NOAC-associated bleeding in daily care. This review appraises trial and registry (or "real-world") data pertaining to bleeding complications in patients taking NOACs and VKA and provides practical recommendations for the management of acute bleeding situations. PMID:25940651

  14. Honey Bee Venom (Apis mellifera Contains Anticoagulation Factors and Increases the Blood-clotting Time

    Directory of Open Access Journals (Sweden)

    Hossein Zolfagharian

    2015-12-01

    Full Text Available Objectives: Bee venom (BV is a complex mixture of proteins and contains proteins such as phospholipase and melittin, which have an effect on blood clotting and blood clots. The mechanism of action of honey bee venom (HBV, Apis mellifera on human plasma proteins and its anti-thrombotic effect were studied. The purpose of this study was to investigate the anti-coagulation effect of BV and its effects on blood coagulation and purification. Methods: Crude venom obtained from Apis mellifera was selected. The anti-coagulation factor of the crude venom from this species was purified by using gel filtration chromatography (sephadex G-50, and the molecular weights of the anti-coagulants in this venom estimated by using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE. Blood samples were obtained from 10 rabbits, and the prothrombin time (PT and the partial thromboplastin time (PTT tests were conducted. The approximate lethal dose (LD values of BV were determined. Results: Crude BV increased the blood clotting time. For BV concentrations from 1 to 4 mg/mL, clotting was not observed even at more than 300 seconds, standard deviations (SDs = ± 0.71; however, clotting was observed in the control group 13.8 s, SDs = ± 0.52. Thus, BV can be considered as containing anti-coagulation factors. Crude BV is composed 4 protein bands with molecular weights of 3, 15, 20 and 41 kilodalton (kDa, respectively. The LD50 of the crude BV was found to be 177.8 μg/mouse. Conclusion: BV contains anti-coagulation factors. The fraction extracted from the Iranian bees contains proteins that are similar to anti-coagulation proteins, such as phospholipase A2 (PLA2 and melittin, and that can increase the blood clotting times in vitro.

  15. The enhanced anticoagulation for graphene induced by COOH(+) ion implantation.

    Science.gov (United States)

    Liu, Xiaoqi; Cao, Ye; Zhao, Mengli; Deng, Jianhua; Li, Xifei; Li, Dejun

    2015-01-01

    Graphene may have attractive properties for some biomedical applications, but its potential adverse biological effects, in particular, possible modulation when it comes in contact with blood, require further investigation. Little is known about the influence of exposure to COOH(+)-implanted graphene (COOH(+)/graphene) interacting with red blood cells and platelets. In this paper, COOH(+)/graphene was prepared by modified Hummers' method and implanted by COOH(+) ions. The structure and surface chemical and physical properties of COOH(+)/graphene were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and contact angle measurement. Systematic evaluation of anticoagulation, including in vitro platelet adhesion assays and hemolytic assays, proved that COOH(+)/graphene has significant anticoagulation. In addition, at the dose of 5 × 10(17) ions/cm(2), COOH(+)/graphene responded best on platelet adhesion, aggregation, and platelet activation.

  16. Pilot-Scale Fermentation Study of a Low Bleeding Anticoagulant Protein in Pichia pastoris%重组低出血抗凝蛋白在毕赤酵母中的中试发酵工艺研究及其纯化与鉴定

    Institute of Scientific and Technical Information of China (English)

    郝木强; 李彦英; 刘春杰; 王秀冬; 刘晶晶; 李艳琪; 刘洋; 吴祖泽; 靳继德

    2013-01-01

      Objective: To establish a practical method of pilot-scale yeast fermentation for the production of a low bleeding anticoagulant protein recombinant-EPR-hirudin(EH). Methods:The growth curve of recombinant Pi⁃chia pastoris secreting EH in shake flask cultivation was determined. Then, according to the determined growth curve, strains were amplified by two shake flask cultures and were directly inoculated into fermentation broth of 500 L. The fermentation was dynamically monitored by the dissolved oxygen and absorbance in 600 nm of the broth, and the wet weight of the strains as well. The target protein expression was induced with methanol feeding. After fermentation, the target proteins were purified through ultrafiltration and a two-step ion-exchange chromatogra⁃phy. The purity of target proteins was analyzed by SDS-PAGE and HPLC, and the molecular weight was exam⁃ined by reducing SDS-PAGE and mass spectrometry. Furthermore, EH was identified by Western blotting, and its anticoagulant activity was analyzed by a clot method. Results: After direct inoculation from flask cultivation, the re⁃combinant engineering yeasts grew well in a fermenter of 500 L tank volume. The total protein content of fermenta⁃tion supernatants was 1.41 g/L at the end of the fermentation. After separation and purification, 21 g of EH pro⁃tein was obtained. The results of the non-reducing SDS-PAGE and HPLC analysis showed that the purity of EH was more than 95%. The relative molecular weight of EH was about 7.3±0.73 kD determined by mass spectrome⁃ try analysis, however, displayed about 13.2±0.2 kD under the SDS-PAGE analysis. The result of Western blotting indicated that the EH protein can be recognized by the commercial mouse anti-hirudin antibody. Moreover, the an⁃ti-thrombin activity of EH protein was about 512~1024 ATU/mg after incubation with bovine coagulation factor Xa. Conclusion: We have developed a simple and convenient method of pilot-scale yeast fermentation

  17. D-dimer: a useful tool in gauging optimal duration of oral anticoagulant therapy?

    Directory of Open Access Journals (Sweden)

    M. Silingardi

    2013-05-01

    Full Text Available BACKGROUND AND AIM OF THE STUDY Optimal duration of oral anticoagulant therapy (OAT in idiopathic venous thromboembolism (VTE is unknown. Indefinite OAT carries an unacceptable risk of major bleeding and prospective studies have demonstrated that OAT is no longer protective after its withdrawal. How to identify the patients at risk for recurrence? D-dimer is a marker of thrombin activity. Early prospective studies showed that elevated D-dimer levels after anticoagulation had a highly predictive value for a recurrent episode. Does D-dimer assay have a role in gauging the appropriate duration of anticoagulant therapy? The PROLONG study tries to answer this question. METHOD D-dimer assay was performed one month after stopping anticoagulation. Patiens with normal D-dimer levels did not resume anticoagulation while patients with elevated D-dimer levels were randomized to discontinue or resume anticoagulation. Study end-points was the composite of recurrent VTE and major bleeding during an average follow-up of 1.4 years. RESULTS The rate of recurrence is significantly higher in patients with elevated D-dimer levels who discontinued anticoagulation. Resuming anticoagulation in this cohort of patients markedly reduces recurrent events without increasing major bleeding. DISCUSSION AND CONCLUSIONS PROLONG study is provocative, because D-dimer assay is simple, thus not requiring dedicated laboratory facilities. D-dimer test has otherwise high sensitivity but low specificity in VTE diagnosis. Aspecifically elevated D-dimer levels are available in the elderly and the majority of patients included in the study were > 65 years old, thus introducing a possible selection bias. Nonetheless the results of the study are useful for the clinician. Prolongation of vitamin K antagonists in patients with elevated D-dimer levels one month after discontinuation of OAT for a first unprovoked episode of VTE results in a favourable risk-benefit relationship. Probably this

  18. [Protein kinase C activation induces platelet apoptosis].

    Science.gov (United States)

    Zhao, Li-Li; Chen, Meng-Xing; Zhang, Ming-Yi; Dai, Ke-Sheng

    2013-10-01

    Platelet apoptosis elucidated by either physical or chemical compound or platelet storage occurs wildly, which might play important roles in controlling the numbers and functions of circulated platelets, or in the development of some platelet-related diseases. However, up to now, a little is known about the regulatory mechanisms of platelet apoptosis. Protein kinase C (PKC) is highly expressed in platelets and plays central roles in regulating platelet functions. Although there is evidence indicating that PKC is involved in the regulation of apoptosis of nucleated cells, it is still unclear whether PKC plays a role in platelet apoptosis. The aim of this study was to investigate the role of PKC in platelet apoptosis. The effects of PKC on mitochondrial membrane potential (ΔΨm), phosphatidylserine (PS) exposure, and caspase-3 activation of platelets were analyzed by flow cytometry and Western blot. The results showed that the ΔΨm depolarization in platelets was induced by PKC activator in time-dependent manner, and the caspase-3 activation in platelets was induced by PKC in concentration-dependent manner. However, the platelets incubated with PKC inhibitor did not results in ΔΨm depolarization and PS exposure. It is concluded that the PKC activation induces platelet apoptosis through influencing the mitochondrial functions and activating caspase 3. The finds suggest a novel mechanism for PKC in regulating platelet numbers and functions, which has important pathophysiological implications for thrombosis and hemostasis.

  19. The use of vitamin K in patients on anticoagulant therapy: a practical guide.

    Science.gov (United States)

    Hanslik, Thomas; Prinseau, Jacques

    2004-01-01

    Anticoagulation with antivitamin K (AVK) is very effective for primary and secondary prevention of thromboembolic events. However, questions persist about the risks and management of over-anticoagulation. For reversal of excessive anticoagulation by warfarin, AVK withdrawal, oral or parenteral vitamin K administration, prothrombin complex or fresh frozen plasma may be used, depending on the excess of anticoagulation, the existence and site of active bleeding, patient characteristics and the indication for AVK. In over-anticoagulated patients, vitamin K aims at rapid lowering of the international normalized ratio (INR) into a safe range to reduce the risk of major bleeding and therefore improving patient outcome without exposing the patient to the risk of thromboembolism due to overcorrection, resistance to AVK, or an allergic reaction to the medication. The risk of bleeding increases dramatically when the INR exceeds 4.0-6.0, although the absolute risk of bleeding remains fairly low, 10.0, a dose of 5mg may be more appropriate. Overcorrection of the INR or resistance to warfarin is unlikely if the above doses of vitamin K are used. Vitamin K is less effective for over-anticoagulation after treatment with acenocoumarol or phenprocoumon than after treatment with warfarin.

  20. New oral anticoagulants: clinical indications, monitoring and treatment of acute bleeding complications.

    Science.gov (United States)

    Fenger-Eriksen, C; Münster, A-M; Grove, E L

    2014-07-01

    New oral anticoagulants like the direct thrombin inhibitor, dabigatran (Pradaxa®), and factor Xa-inhibitors, rivaroxaban (Xarelto®) and apixaban (Eliquis®) are available for prophylaxis and treatment of thromboembolic disease. They are emerging alternatives to warfarin and provide equal or better clinical outcome together with reduced need for routine monitoring. Methods for measuring drug concentrations are available, although a correlation between plasma drug concentrations and the risk of bleeding has not been firmly established. Standard laboratory measures like prothrombin time and activated partial thromboplastin time are not sensitive enough to detect thrombin or factor Xa inhibition provided by new oral anticoagulants. Thus, these standard tests may only be used as a crude estimation of the actual anticoagulation status. Further challenges regarding patients receiving new oral anticoagulants who presents with major bleeding or need for emergency surgery pose a unique problem. No established agents are clinically available to reverse the anticoagulant effect, although preclinical data report prothrombin complex concentrate as more efficient than fresh frozen plasma or other prohaemostatic agents. This review summaries current knowledge on approved new oral anticoagulants and discusses clinical aspects of monitoring, with particular focus on the management of the bleeding patient.

  1. Occurrence, elimination, and risk of anticoagulant rodenticides and drugs during wastewater treatment.

    Science.gov (United States)

    Gómez-Canela, Cristian; Barata, Carlos; Lacorte, Silvia

    2014-01-01

    Anticoagulants are biocides widely used as pest control agents in agriculture, urban infrastructures, and domestic applications for the control of rodents. Other anticoagulants such as warfarin and acenocoumarol are also used as drugs against thrombosis. After use, anticoagulants are discharged to sewage grids and enter wastewater treatment plants (WWTPs). Our hypothesis is that WWTP effluents can be a source of anticoagulants to receiving waters and that these can affect aquatic organisms and other nontarget species. Therefore, the objective of the present study was to determine the occurrence of 11 anticoagulants in WWTPs receiving urban and agricultural wastewaters. Warfarin was the most ubiquitous compound detected in influent waters and was partially eliminated during the activated sludge treatment, and low nanograms per liter concentration were found in the effluents. Other detected compounds were coumatetralyl, ferulenol, acenocoumarol, flocoumafen, brodifacoum, bromadiolone, and difenacoum at concentrations of 0.86-87.0 ng L(-1). Considering water volumes of each WWTP, daily emissions were estimated to be 0.02 to 21.8 g day(-1), and thus, WWTPs contribute to the loads of anticoagulants to receiving waters. However, low aquatic toxicity was observed using Daphnia magna as a model aquatic organism. PMID:24622989

  2. Human monoclonal antiphospholipid antibodies disrupt the annexin A5 anticoagulant crystal shield on phospholipid bilayers: evidence from atomic force microscopy and functional assay.

    Science.gov (United States)

    Rand, Jacob H; Wu, Xiao-Xuan; Quinn, Anthony S; Chen, Pojen P; McCrae, Keith R; Bovill, Edwin G; Taatjes, Douglas J

    2003-09-01

    The antiphospholipid (aPL) syndrome is an autoimmune condition that is marked by recurrent pregnancy losses and/or systemic vascular thrombosis in patients who have antibodies against phospholipid/co-factor complexes. The mechanism(s) for pregnancy losses and thrombosis in this condition is (are) not known. Annexin A5 is a potent anticoagulant protein, expressed by placental trophoblasts and endothelial cells, that crystallizes over anionic phospholipids, shielding them from availability for coagulation reactions. We previously presented data supporting the hypothesis that aPL antibody-mediated disruption of the anticoagulant annexin A5 shield could be a thrombogenic mechanism in the aPL syndrome. However, this has remained a subject of controversy. We therefore used atomic force microscopy, a method previously used to study the crystallization of annexin A5, to image the effects of monoclonal human aPL antibodies on the crystal structure of the protein over phospholipid bilayers. In the presence of the aPL monoclonal antibodies (mAbs) and beta(2)-GPI, the major aPL co-factor, structures presumed to be aPL mAb-antigen complexes were associated with varying degrees of disruption to the annexin A5 crystallization pattern over the bilayer. In addition, measurements of prothrombinase activity on the phospholipid bilayers showed that the aPL mAbs reduced the anti-coagulant effect of annexin A5 and promoted thrombin generation. These data provide morphological evidence that support the hypothesis that aPL antibodies can disrupt annexin A5 binding to phospholipid membranes and permit increased generation of thrombin. The aPL antibody-mediated disruption of the annexin A5 anticoagulant shield may be an important prothrombotic mechanism in the aPL syndrome. PMID:12937161

  3. Specific antidotes against direct oral anticoagulants: A comprehensive review of clinical trials data.

    Science.gov (United States)

    Tummala, Ramyashree; Kavtaradze, Ana; Gupta, Anjan; Ghosh, Raktim Kumar

    2016-07-01

    The Vitamin K antagonist warfarin was the only oral anticoagulant available for decades for the treatment of thrombosis and prevention of thromboembolism until Direct Oral Anticoagulants (DOACs); a group of new oral anticoagulants got approved in the last few years. Direct thrombin inhibitor: dabigatran and factor Xa inhibitors: apixaban, rivaroxaban, and edoxaban directly inhibit the coagulation cascade. DOACs have many advantages over warfarin. However, the biggest drawback of DOACs has been the lack of specific antidotes to reverse the anticoagulant effect in emergency situations. Activated charcoal, hemodialysis, and activated Prothrombin Complex Concentrate (PCC) were amongst the nonspecific agents used in a DOAC associated bleeding but with limited success. Idarucizumab, the first novel antidote against direct thrombin inhibitor dabigatran was approved by US FDA in October 2015. It comprehensively reversed dabigatran-induced anticoagulation in a phase I study. A phase III trial on Idarucizumab also complete reversal of anticoagulant effect of dabigatran. Andexanet alfa (PRT064445), a specific reversal agent against factor Xa inhibitors, showed a complete reversal of anticoagulant activity of apixaban and rivaroxaban within minutes after administration without adverse effects in two recently completed parallel phase III trials ANNEXA-A and ANNEXA-R respectively. It is currently being studied in ANNEXA-4, a phase IV study. Aripazine (PER-977), the third reversal agent, has shown promising activity against dabigatran, apixaban, rivaroxaban, as well as subcutaneous fondaparinux and LMWH. This review article summarizes pharmacological characteristics of these novel antidotes, coagulation's tests affected, available clinical and preclinical data, and the need for phase III and IV studies. PMID:27082776

  4. Direct oral anticoagulants: a guide for daily practice.

    Science.gov (United States)

    Fontana, Pierre; Robert-Ebadi, Helia; Bounameaux, Henri; Boehlen, Françoise; Righini, Marc

    2016-01-01

    In recent years, small oral compounds that specifically block activated coagulation factor X (FXa) or thrombin (FIIa) have become alternatives to the anticoagulants that had been used for several decades. As of today, these direct oral anticoagulants (DOACs) include dabigatran etexilate (thrombin inhibitor) and apixaban, edoxaban and rivaroxaban (inhibitors of FXa). While there is no doubt that DOACs represent a major step forward in the management of patients with venous thromboembolic disease and atrial fibrillation, new challenges have arisen. They need to be addressed with the necessary pragmatism on the basis of evidence. Indeed, a better understanding of the management of these last-generation antithrombotics will favour safer use and increase confidence of the practitioner for the prescription of these drugs. The aim of this article is to present practical suggestions for the prescription and use of these drugs in everyday clinical practice, based on clinical experience and recently updated recommendations of the European Heart Rhythm Association and the American College of Chest Physicians among other scientific organisations. We address issues such as pharmacokinetics, dosing, side effects, limitations of use, drug interactions, switching from and to other anticoagulants, renal function, concomitant administration of antiplatelet agents and perioperative use. We also address the issue of monitoring and reversal, taking advantage of the most recent development in this latter area. Rather than being one additional set of recommendations, our narrative review aims at assisting the practicing physician in his or her daily handling of these novel anticoagulant compounds, based on frequently asked questions to the authors, a group of experienced specialists in the field who have, however, no commitment to issue guidelines. PMID:26964028

  5. Strategies for urgent reversal of target-specific oral anticoagulants.

    Science.gov (United States)

    Davis, Estella M; Uhlmeyer, Erin M; Schmidt, David P; Schardt, Greg L

    2014-12-01

    The direct thrombin inhibitor dabigatran and factor Xa inhibitors rivaroxaban and apixaban are US Food and Drug Administration (FDA)-approved target-specific oral anticoagulants (TSOACs) that have emerged onto the market for use in some indications similar to those for warfarin; in addition, edoxaban is seeking FDA approval. Similar indications include reducing the risk of stroke and systemic embolism in patients with nonvalvular atrial fibrillation for all 3 agents, for the prevention of deep vein thrombosis that may lead to pulmonary embolism in patients undergoing hip or knee surgery for rivaroxaban and apixaban, and for the treatment and prevention of deep vein thrombosis and pulmonary embolism. As anticoagulants, they are all associated with a risk of bleeding, and, unfortunately, there are no approved antidotes for reversal of these agents. A number of small studies in human subjects and in human/animal models exposed to TSOACs have evaluated the use of activated charcoal, hemodialysis for dabigatran, or clotting factor concentrates for their ability to neutralize the anticoagulant effects or reduce drug concentrations of TSOACs. Clotting factor concentrates that have been used include prothrombin complex concentrates and recombinant factor VII. This review examines studies and case reports evaluating these strategies for expedited or emergent reversal of TSOACs. PMID:25485923

  6. Novel oral anticoagulants for heparin-induced thrombocytopenia.

    Science.gov (United States)

    Skelley, Jessica W; Kyle, Jeffrey A; Roberts, Rachel A

    2016-08-01

    To review the use of the novel oral anticoagulant (NOAC) agents for the treatment of heparin-induced thrombocytopenia (HIT) from relevant clinical trial data. A MEDLINE, International Pharmaceutical Abstracts, ClinicalTrials.gov, and Google-Scholar searches (1966-March 2016) were conducted using the keywords: thrombocytopenia, NOACs, dabigatran, apixaban, rivaroxaban, edoxaban, Xa inhibitor, direct thrombin inhibitor. Articles evaluating the new oral anticoagulants for thrombocytopenia published in English and using human subjects were selected. Eight clinical trials were identified. References cited in identified articles were used for additional citations. Approximately 12 million hospitalized patients each year are exposed to heparin for thromboprophylaxis. HIT, an immune-mediated, prothrombotic adverse reaction is a potential complication of heparin therapy. As a result, heparin products must be immediately withdrawn and replaced by alternative anticoagulants to compensate for the thrombotic risk associated with HIT. Limitations exist with the only currently FDA approved heparin alternative, argatroban. NOACs have been considered as potential alternatives to traditional agents based on their pharmacologic activity. Case reports have indicated positive results in patients, with clinical outcomes and tolerability supporting the use of the NOACs as alternative agents in the treatment of HIT. Positive results have been reported for the use of NOACs in the treatment of HIT. Further robust studies are needed for definitive decision making by clinicians. PMID:27102287

  7. Survival of heparins, oral anticoagulants, and aspirin after the year 2010.

    Science.gov (United States)

    Fareed, Jawed; Hoppensteadt, Debra A; Fareed, Daniel; Demir, Muzaffer; Wahi, Rakesh; Clarke, Melaine; Adiguzel, Cafer; Bick, Rodger

    2008-02-01

    The conventional management of thrombotic and cardiovascular disorders is based on the use of heparin, oral anticoagulants, and aspirin. Despite remarkable progress in life sciences, these drugs still remain a challenge and a mystery to us, and their use is far from optimized. The development of low-molecular-weight heparins and the synthesis of heparinomimetics, such as the chemically synthesized pentasaccharide, represent a refined use of heparin. Additional drugs from this knowledge will continue to develop; however, none of these drugs will ever match the polypharmacology of heparin. Aspirin still remains the leading drug in the management of thrombotic and cardiovascular disorders. The newer antiplatelet drugs such as adenosine diphosphate receptor inhibitors, glycoprotein IIb/IIIa inhibitors, and other specific inhibitors have limited effects and have been tested in patients who have already been treated with aspirin. Warfarin provides a convenient and affordable approach in the long-term outpatient management of thrombotic disorders. The optimized use of these drugs still remains as the approach of choice to manage thrombotic disorders. The new anticoagulant targets, including specific sites in the hemostatic network such as tissue factor, individual clotting factors (IIa, VIIa, IXa, Xa, XIIa, and XIIIa), recombinant forms of serpins (antithrombin, heparin cofactor II, and tissue factor pathway inhibitors), recombinant activated protein C, thrombomodulin, and site-specific serine protease inhibitor complexes have also been developed. There is a major thrust on the development of orally bioavailable anticoagulant drugs (anti-Xa and anti-IIa agents), which are slated to replace oral anticoagulants. Both the anti-factor Xa and antithrombin agents have been developed for oral use and have provided impressive clinical outcomes in sponsor trials for the postsurgical prophylaxis of venous thrombosis; however, safety concerns related to liver enzyme elevations and

  8. Isolation,purification and anticoagulant activity of the polysaccharide from the leaves of mulberry%桑叶多糖的分离纯化及其抗凝血活性的研究

    Institute of Scientific and Technical Information of China (English)

    张入飞; 蔡为荣; 谢亮亮; 杨蕾; 陈俏

    2015-01-01

    To study different components of mulberry polysaccharides and their anticoagulant activity,the crude mulberry polysaccharides were extracted by water and precipitated by alcohol.The crude polysac-charides were decolorized and deproteinized by polyamide.Five water-soluble polysaccharides (MPS-1 , MPS-2a,MPS-2b,MPS-2c and MPS-3)were purified by DEAE sepharose CL-6B chromatograph column and sepharose CL-6B chromatograph column.The monosaccharide compostion of MPS was composed mainly of galactose,glucose,rhamnose,arabinose,xylose and mannose and so on.APTT,PT and TT in vitro tests showed that they prolonged APTT and TT,but had no significant effect on PT.The result confirmed these in the regulation of coagulation initiated via the intrinsic pathway or common pathway;MPS-2b significantly prolonged APTT and TT compared to saline in experiment concentrations.These results suggest that the mulberry polysaccharide MPS-2b can be explored as a kind of natural potential anticoagulant.%为了研究桑叶多糖不同组分在体外的抗凝血活性,采用水提醇沉法提取桑叶粗多糖,聚酰胺进行脱色和脱蛋白。用DEAE sepharose CL-6B 和 sepharose CL-6B 对桑叶多糖进行纯化,得到5种水溶性多糖组分(MPS-1、MPS-2a、MPS-2b、MPS-2c和 MPS-3)。单糖检测结果表明:桑叶多糖主要是由半乳糖、葡萄糖、鼠李糖、阿拉伯糖、木糖和甘露糖等组成。体外抗凝血活性检测显示5种桑叶多糖组分均能延长活化部分凝血活酶时间(activated partial thromboplastin time,APTT)和凝血酶时间(thrombin time,TT)、而对凝血酶原时间(prothrombin time,PT)影响不显著,说明它们是通过影响内源性途径或共同途径而发挥抗凝血作用;与对照相比,MPS-2b在试验浓度范围内对 APTT 和 TT 的效果达到极显著,表明 MPS-2b 有潜力开发成抗凝血活性物质。

  9. Parenteral anticoagulation in patients with cancer who have no therapeutic or prophylactic indication for anticoagulation

    NARCIS (Netherlands)

    E.A. Akl; S. Gunukula; M. Barba; V.E.D. Yosuico; F.F. van Doormaal; S. Kuipers; S. Middeldorp; H.O. Dickinson; A. Bryant; H. Schuenemann

    2011-01-01

    Background Anticoagulation may improve survival in patients with cancer through an antitumor effect in addition to the perceived antithrombotic effect. Objectives To evaluate the efficacy and safety of parenteral anticoagulants in patients with cancer with no therapeutic or prophylactic indication f

  10. Non-vitamin K antagonist oral anticoagulation agents in anticoagulant naive atrial fibrillation patients

    DEFF Research Database (Denmark)

    Olesen, Jonas Bjerring; Sørensen, Rikke; Hansen, Morten Lock;

    2015-01-01

    . Older age, female gender, and prior stroke were some of the factors associated with NOAC use vs. warfarin, whereas chronic kidney disease, myocardial infarction, and heart failure showed the opposite association. CONCLUSION: Among oral anticoagulation-naïve AF patients initiated on oral anticoagulation...

  11. Pyrrolopyridine inhibitors of mitogen-activated protein kinase-activated protein kinase 2 (MK-2).

    Science.gov (United States)

    Anderson, David R; Meyers, Marvin J; Vernier, William F; Mahoney, Matthew W; Kurumbail, Ravi G; Caspers, Nicole; Poda, Gennadiy I; Schindler, John F; Reitz, David B; Mourey, Robert J

    2007-05-31

    A new class of potent kinase inhibitors selective for mitogen-activated protein kinase-activated protein kinase 2 (MAPKAP-K2 or MK-2) for the treatment of rheumatoid arthritis has been prepared and evaluated. These inhibitors have IC50 values as low as 10 nM against the target and have good selectivity profiles against a number of kinases including CDK2, ERK, JNK, and p38. These MK-2 inhibitors have been shown to suppress TNFalpha production in U397 cells and to be efficacious in an acute inflammation model. The structure-activity relationships of this series, the selectivity for MK-2 and their activity in both in vitro and in vivo models are discussed. The observed selectivity is discussed with the aid of an MK-2/inhibitor crystal structure.

  12. Study on Anti-Coagulant Activity of Sulfated Nsotoc Sphaeroides Kützing Polysaccharide%葛仙米多糖硫酸酯抗凝血活性研究

    Institute of Scientific and Technical Information of China (English)

    朱玉婷; 袁杰; 杨洁; 田瑞; 曾智; 莫开菊

    2014-01-01

    This paper investigated the anticoagulant activity of Nostoc Sphaeroides Kützing polysaccha-ride’ s sulfuric acid ester,whose substitution degrees were 0,0.51,1.01 respectively.The results showed:Nostoc Sphaeroides Kützing polysaccharide’ s sulfuric acid ester could obviously prolong APTT and TT, and depended on the concentration but did not play a significant role to PT.So the results mainly illustra-ted that it played the function of anticlotting through inhibiting endogenous blood coagulation process and conjunct blood coagulation way,but it showed weak effect on exogenous blood coagulation way.%以取代度为0、0.51、1.01的葛仙米多糖硫酸酯为原料,探讨了各样品的抗凝血活性.结果表明:葛仙米多糖硫酸酯能显著延长人活化部分凝血活酶时间(APTT)和凝血酶时间(TT),且具有一定的剂量效应关系,但对凝血酶原时间(PT)的作用不明显.说明其主要是通过抑制内源性凝血过程及共同凝血途径发挥抗凝血作用,对外源凝血途径影响较弱.

  13. Arabinogalactan proteins: focus on carbohydrate active enzymes

    Directory of Open Access Journals (Sweden)

    Eva eKnoch

    2014-06-01

    Full Text Available Arabinogalactan proteins (AGPs are a highly diverse class of cell surface proteoglycans that are commonly found in most plant species. AGPs play important roles in many cellular processes during plant development, such as reproduction, cell proliferation, pattern formation and growth, and in plant-microbe interaction. However, little is known about the molecular mechanisms of their function. Numerous studies using monoclonal antibodies that recognize different AGP glycan epitopes have shown the appearance of a slightly altered AGP glycan in a specific stage of development in plant cells. Therefore, it is anticipated that the biosynthesis and degradation of AGP glycan is tightly regulated during development. Until recently, however, little was known about the enzymes involved in the metabolism of AGP glycans. In this review, we summarize recent discoveries of carbohydrate active enzymes (CAZy; http://www.cazy.org/ involved in the biosynthesis and degradation of AGP glycans, and we discuss the biological role of these enzymes in plant development.

  14. Observation of microtubule-based motor protein activity.

    Science.gov (United States)

    Sloboda, Roger D

    2015-02-01

    It is possible to detect the presence of motor proteins that have the ability to translocate particles along microtubules. The two procedures described here were developed to detect microtubule-dependent motor protein activity in cell lysates or of purified proteins. In the first procedure, latex beads bound to the putative motor protein are assayed for their ability to translocate along microtubules in an ATP-dependent fashion. If motor protein activity is present, it will bind to the beads and translocate them unidirectionally along the microtubules. In the second procedure, motor proteins induce microtubule gliding over a glass coverslip surface that is coated with active motor protein. Because the mass of a microtubule is negligible compared to that of a coverslip or slide, the microtubule glides over the glass surface when the surface is coated with active motor protein. Also included here are descriptions of assays designed to determine the directionality of movement of microtubule-based motor proteins. PMID:25646501

  15. Newer Oral Anticoagulants: Stroke Prevention and Pitfalls.

    Science.gov (United States)

    Patel, Anand; Goddeau, Richard P; Henninger, Nils

    2016-01-01

    Warfarin is very effective in preventing stroke in patients with atrial fibrillation. However, its use is limited due to fear of hemorrhagic complications, unpredictable anticoagulant effects related to multiple drug interactions and dietary restrictions, a narrow therapeutic window, frequent difficulty maintaining the anticoagulant effect within a narrow therapeutic window, and the need for inconvenient monitoring. Several newer oral anticoagulants have been approved for primary and secondary prevention of stroke in patients with non-valvular atrial fibrillation. These agents have several advantages relative to warfarin therapy. As a group, these direct oral anticoagulants (DOAC), which include the direct thrombin inhibitor, dabigatran, and the factor Xa inhibitors (rivaroxaban, apixaban, and edoxaban), are more effective than dose adjusted warfarin for prevention of all-cause stroke (including both ischemic and hemorrhagic stroke), and have an overall more favorable safety profile. Nevertheless, an increased risk of gastrointestinal bleeding (with the exception of apixaban), increased risk for thrombotic complication with sudden discontinuation, and inability to accurately assess and reverse anticoagulant effect require consideration prior to therapy initiation, and pose a challenge for decision making in acute stroke therapy. PMID:27347226

  16. Reconstitution of Membrane Proteins into Model Membranes: Seeking Better Ways to Retain Protein Activities

    OpenAIRE

    Trevor Lithgow; Lisa Martin; Hsin-Hui Shen

    2013-01-01

    The function of any given biological membrane is determined largely by the specific set of integral membrane proteins embedded in it, and the peripheral membrane proteins attached to the membrane surface. The activity of these proteins, in turn, can be modulated by the phospholipid composition of the membrane. The reconstitution of membrane proteins into a model membrane allows investigation of individual features and activities of a given cell membrane component. However, the activity of mem...

  17. Selection of anticoagulant solution to the hemolymph of Chlamys farreri by transmission electron microscropy and flow cytometry

    Institute of Scientific and Technical Information of China (English)

    Chen Muyan; Yang Hongsheng; Shi Fangfang

    2007-01-01

    Mixtures of hemolymph from Chlamys farreri with three different anticoagulant solutions were incubated for an hour in vitro , then the ultrastructural alterations of hemocytes were observed , and the aggregation rate was analyzed by using transmission electron microscropy and flow cytometry respectively. The results showed that Formula 3 (glucose 20. 8 g L-1; EDTA 20mM ; sodium chloride 20 g L-1 ; Tris-HCl 0.05M;pH 7. 4) was the desirable anticoagulant solution for C . Farreri hemocytes. Further phagocytosis assay showed that no obvious negative effect was given to the hemocyte phagocytic activity when using Formula 3 as the anticoagulant solution.

  18. The pharmacology of novel oral anticoagulants.

    Science.gov (United States)

    DeWald, Tracy A; Becker, Richard C

    2014-01-01

    Anticoagulation for the prevention of stroke is an important aspect of the management of atrial fibrillation. Novel anticoagulants including oral factor Xa inhibitors rivaroxaban and apixaban and the direct thrombin inhibitor dabigatran have emerged as important therapeutic treatment options for prevention of stroke in non-valvular atrial fibrillation. These agents offer practical advantages over traditional vitamin K antagonists, however an understanding of their individual pharmacokinetic and other agent-specific differences is essential for identifying appropriate candidates for therapy, and for selecting the appropriate agent that will be effective and safe. Here, we review the pharmacokinetic process of oral medication use, summarize the newer anticoagulants, their pharmacology, individual pharmacokinetic features, and explore possible explanations for the differences in bleeding outcomes observed in the clinical trials. PMID:23860880

  19. [New oral anticoagulants for atrial fibrillation: a neurologist's view

    NARCIS (Netherlands)

    Dijk, E.J. van; Koudstaal, P.J.; Roos, Y.B.; Brouwers, P.J.; Kappelle, L.J.

    2012-01-01

    - Recent randomized controlled trials have shown that new oral anticoagulants (dabigatran, rivaroxaban en apixaban) in patients with atrial fibrillation are equally or more effective in preventing cerebral infarction than vitamin K antagonists (VKA).- New oral anticoagulants cause significant less i

  20. Excessive anticoagulation with warfarin or phenprocoumon may have multiple causes

    DEFF Research Database (Denmark)

    Meegaard, Peter Martin; Holck, Line H V; Pottegård, Anton;

    2012-01-01

    Excessive anticoagulation with vitamin K antagonists is a serious condition with a substantial risk of an adverse outcome. We thus found it of interest to review a large case series to characterize the underlying causes of excessive anticoagulation....

  1. Activated protein C ameliorates Bacillus anthracis lethal toxin-induced lethal pathogenesis in rats

    Directory of Open Access Journals (Sweden)

    Kau Jyh-Hwa

    2012-11-01

    Full Text Available Abstract Background Lethal toxin (LT is a major virulence factor of Bacillus anthracis. Sprague Dawley rats manifest pronounced lung edema and shock after LT treatments, resulting in high mortality. The heart failure that is induced by LT has been suggested to be a principal mechanism of lung edema and mortality in rodents. Since LT-induced death occurs more rapidly in rats than in mice, suggesting that other mechanisms in addition to the heart dysfunction may be contributed to the fast progression of LT-induced pathogenesis in rats. Coagulopathy may contribute to circulatory failure and lung injury. However, the effect of LT on coagulation-induced lung dysfunction is unclear. Methods To investigate the involvement of coagulopathy in LT-mediated pathogenesis, the mortality, lung histology and coagulant levels of LT-treated rats were examined. The effects of activated protein C (aPC on LT-mediated pathogenesis were also evaluated. Results Fibrin depositions were detected in the lungs of LT-treated rats, indicating that coagulation was activated. Increased levels of plasma D-dimer and thrombomodulin, and the ameliorative effect of aPC further suggested that the activation of coagulation-fibrinolysis pathways plays a role in LT-mediated pathogenesis in rats. Reduced mortality was associated with decreased plasma levels of D-dimer and thrombomodulin following aPC treatments in rats with LT-mediated pathogenesis. Conclusions These findings suggest that the activation of coagulation in lung tissue contributes to mortality in LT-mediated pathogenesis in rats. In addition, anticoagulant aPC may help to develop a feasible therapeutic strategy.

  2. Syndecans: synergistic activators of cell adhesion

    DEFF Research Database (Denmark)

    Woods, A; Couchman, J R

    1998-01-01

    Cell-surface proteoglycans participate in cell adhesion, growth-factor signalling, lipase activity and anticoagulation. Until recently, only the roles of the glycosaminoglycan chains were investigated. Now, with molecular characterization of several core proteins, the roles of each individual...... molecules modulating integrin-based adhesion....

  3. Management of the Bleeding Patient Receiving New Oral Anticoagulants: A Role for Prothrombin Complex Concentrates

    Directory of Open Access Journals (Sweden)

    Lisa M. Baumann Kreuziger

    2014-01-01

    Full Text Available Ease of dosing and simplicity of monitoring make new oral anticoagulants an attractive therapy in a growing range of clinical conditions. However, newer oral anticoagulants interact with the coagulation cascade in different ways than traditional warfarin therapy. Replacement of clotting factors will not reverse the effects of dabigatran, rivaroxaban, or apixaban. Currently, antidotes for these drugs are not widely available. Fortunately, withholding the anticoagulant and dialysis are freqnently effective treatments, particularly with rivaroxaban and dabigatran. Emergent bleeding, however, requires utilization of Prothrombin Complex Concentrates (PCCs. PCCs, in addition to recombinant factor VIIa, are used to activate the clotting system to reverse the effects of the new oral anticoagulants. In cases of refractory or emergent bleeding, the recommended factor concentrate in our protocols differs between the new oral anticoagulants. In patients taking dabigatran, we administer an activated PCC (aPCC [FELBA] due to reported benefit in human in vitro studies. Based on human clinical trial evidence, the 4-factor PCC (Kcentra is suggested for patients with refractory rivaroxaban- or apixaban-associated hemorrhage. If bleeding continues, recombinant factor VIIa may be employed. With all of these new procoagulant agents, the risk of thrombosis associated with administration of factor concentrates must be weighed against the relative risk of hemorrhage.

  4. Pharmacology of anticoagulants used in the treatment of venous thromboembolism

    OpenAIRE

    Nutescu, Edith A.; Burnett, Allison; Fanikos, John; Spinler, Sarah; Wittkowsky, Ann

    2016-01-01

    Anticoagulant drugs are the foundation of therapy for patients with VTE. While effective therapeutic agents, anticoagulants can also result in hemorrhage and other side effects. Thus, anticoagulant therapy selection should be guided by the risks, benefits and pharmacologic characteristics of each agent for each patient. Safe use of anticoagulants requires not only an in-depth knowledge of their pharmacologic properties but also a comprehensive approach to patient management and education. Thi...

  5. Human cytomegalovirus IE2 protein interacts with transcription activating factors

    Institute of Scientific and Technical Information of China (English)

    徐进平; 叶林柏

    2002-01-01

    The human cytomegalovirus (HCMV) IE86 Cdna was cloned into Pgex-2T and fusion protein GST-IE86 was expressed in E. Coli. SDS-PAGE and Western blot assay indicated that fusion protein GST-IE86 with molecular weight of 92 ku is soluble in the supernatant of cell lysate. Protein GST and fusion protein GST-IE86 were purified by affinity chromatography. The technology of co-separation and specific affinity chromatography was used to study the interactions of HCMV IE86 protein with some transcriptional regulatory proteins and transcriptional factors. The results indicated that IE86 interacts separately with transcriptional factor TFIIB and promoter DNA binding transcription trans-activating factors SP1, AP1 and AP2 to form a heterogenous protein complex. These transcriptional trans-activating factors, transcriptional factor and IE86 protein were adsorbed and retained in the affinity chromatography simultaneously. But IE86 protein could not interact with NF-Кb, suggesting that the function of IE86 protein that can interact with transcriptional factor and transcriptional trans-activating factors has no relevance to protein glycosylation. IE86 protein probably has two domains responsible for binding transcriptional trans-activating regulatory proteins and transcriptional factors respectively, thus activating the transcription of many genes. The interactions accelerated the assembly of the transcriptional initiation complexes.

  6. Fatal pulmonary hemorrhage after taking anticoagulation medication

    Directory of Open Access Journals (Sweden)

    Samuel P. Hammar

    2015-01-01

    Full Text Available We describe a 64-year-old man with extensive diffuse acute lung hemorrhage, presumably as a result of anticoagulation therapy. We evaluated reports in the literature concerning acute exacerbation (acute lung injury of unknown cause in UIP and other forms of fibrotic interstitial pneumonias. We also evaluated autopsy tissue in this case in order to determine the cause of death in this 64-year-old man, who was initially thought to have an asbestos-related disease. Based on the autopsy findings, this man died as a result of anticoagulation therapy; specifically, the use of Xarelto® (rivaroxaban.

  7. Anticoagulated patient management in primary care service

    Directory of Open Access Journals (Sweden)

    Marco Antonio Zapata Sampedro

    2008-05-01

    Full Text Available Out-patients undergoing anticoagulant treatment are attended by nursing staff, working with doctors.To be able to provide adequate medical care, nurses must have the minimum knowledge and skills needed to work with the programme described in this article. These include basic and specific knowledge of anticoagulation. The correct functioning of the service will help provide an optimum control of the INR (International Normalized Ratio and reduce the complications of bleeding, both of which are the main objectives of the nursing care of these patients.

  8. 4-hydroxy-2, 3-nonenal activates activator protein-1 and mitogen-activated protein kinases in rat pancreatic stellate cells

    Institute of Scientific and Technical Information of China (English)

    Kazuhiro Kikuta; Atsushi Masamune; Masahiro Satoh; Noriaki Suzuki; Tooru Shimosegawa

    2004-01-01

    AIM: Activated pancreatic stellate cells (PSCs) are implicated in the pathogenesis of pancreatic inflammation and fibrosis,where oxidative stress is thought to play a key role. 4-hydroxy2,3-nonenal (HNE) is generated endogenously during the process of lipid peroxidation, and has been accepted as a mediator of oxidative stress. The aim of this study was to clarify the effects of HNE on the activation of signal transduction pathways and cellular functions in PSCs.METHODS: PSCs were isolated from the pancreas of male Wistar rats after perfusion with collagenase P, and used in their culture-activated, myofibroblast-like phenotype unless otherwise stated. PSCs were treated with physiologically relevant and non-cytotoxic concentrations (up to 5 μmol/L)of HNE. Activation of transcription factors was examined by electrophoretic mobility shift assay and luciferase assay.Activation of mitogen-activated protein (MAP) kinases was assessed by Western blotting using anti-phosphospecific antibodies. Cell proliferation was assessed by measuring the incorporation of 5-bromo-2'-deoxyuridine. Production of type Ⅰ collagen and monocyte chemoattractant protein-1was determined by enzyme-linked immunosorbent assay.The effect of HNE on the transformation of freshly isolated PSCs in culture was also assessed.RESULTS: HNE activated activator protein-1, but not nuclear factor κB. In addition, HNE activated three classes of MAP kinases: extracellular signal-regulated kinase, c-Jun N-terminal kinase, and p38 MAP kinase. HNE increased type Ⅰ collagen production through the activation of p38 MAP kinase and c-Jun N-terminal kinase. HNE did not alter the proliferation,or monocyte chemoattractant protein-1 production. HNE did not initiate the transformation of freshly isolated PSCs to myofibroblast-like phenotype.CONCLUSION: Specific activation of these signal transduction pathways and altered cell functions such as collagen production by HNE may play a role in the pathogenesis of pancreatic

  9. Heat dissipation guides activation in signaling proteins

    OpenAIRE

    Weber, Jeffrey K.; Shukla, Diwakar; Pande, Vijay S.

    2015-01-01

    As with their macroscopic counterparts, the moving parts of nanoscale protein machines grow hot while in operation. A portion of the energy biomolecules harness to perform meaningful work is always dissipated as heat into the surroundings. Here, we feature a methodology by which dominant dissipative trajectories can be extracted from detailed models of protein dynamics. In two important classes of signaling proteins [kinases and G-protein–coupled receptors (GPCRs)], we find that the regions o...

  10. A thrombomodulin mutation that impairs active protein C generation is detrimental in severe pneumonia-derived gram-negative sepsis (melioidosis.

    Directory of Open Access Journals (Sweden)

    Liesbeth M Kager

    2014-04-01

    Full Text Available BACKGROUND: During severe (pneumosepsis inflammatory and coagulation pathways become activated as part of the host immune response. Thrombomodulin (TM is involved in a range of host defense mechanisms during infection and plays a pivotal role in activation of protein C (PC into active protein C (APC. APC has both anticoagulant and anti-inflammatory properties. In this study we investigated the effects of impaired TM-mediated APC generation during melioidosis, a common form of community-acquired Gram-negative (pneumosepsis in South-East Asia caused by Burkholderia (B. pseudomallei. METHODOLOGY/PRINCIPAL FINDINGS: (WT mice and mice with an impaired capacity to activate protein C due to a point mutation in their Thbd gene (TMpro/pro mice were intranasally infected with B. pseudomallei and sacrificed after 24, 48 or 72 hours for analyses. Additionally, survival studies were performed. When compared to WT mice, TMpro/pro mice displayed a worse survival upon infection with B. pseudomallei, accompanied by increased coagulation activation, enhanced lung neutrophil influx and bronchoalveolar inflammation at late time points, together with increased hepatocellular injury. The TMpro/pro mutation had limited if any impact on bacterial growth and dissemination. CONCLUSION/SIGNIFICANCE: TM-mediated protein C activation contributes to protective immunity after infection with B. pseudomallei. These results add to a better understanding of the regulation of the inflammatory and procoagulant response during severe Gram-negative (pneumosepsis.

  11. Antioxidant activity of black bean (Phaseolus vulgaris L. protein hydrolysates

    Directory of Open Access Journals (Sweden)

    Jarine Amaral do EVANGELHO

    2016-01-01

    Full Text Available Abstract The objective of this work was to study the effect of enzymatic hydrolysis of black bean protein concentrate using different enzymes. Bean proteins were extracted and hydrolyzed over a period of 120 min using the enzymes pepsin or alcalase. The protein hydrolysates’ molecular weight was assayed by electrophoresis and the antioxidant activity was evaluated by the capturing methods of free radicals ABTS●+ and DPPH. Electrophoretic results showed that the bands above 50 kDa disappeared, when the beans protein was subjected to hydrolysis with pepsin. The bean protein hydrolysate obtained by hydrolysis with alcalase enzyme, showed higher antioxidant activity for inhibition of the radical ABTS●+. However, the hydrolysates obtained by hydrolysis with pepsin had higher antioxidant activity for inhibition of the radical DPPH. The use of pepsin and alcalase enzymes, under the same reaction time, produced black bean protein hydrolysates with different molecular weight profiles and superior antioxidant activity than the native bean protein.

  12. G protein activation by G protein coupled receptors: ternary complex formation or catalyzed reaction?

    Science.gov (United States)

    Roberts, David J; Waelbroeck, Magali

    2004-09-01

    G protein coupled receptors catalyze the GDP/GTP exchange on G proteins, thereby activating them. The ternary complex model, designed to describe agonist binding in the absence of GTP, is often extended to G protein activation. This is logically unsatisfactory as the ternary complex does not accumulate when G proteins are activated by GTP. Extended models taking into account nucleotide binding exist, but fail to explain catalytic G protein activation. This review puts forward an enzymatic model of G protein activation and compares its predictions with the ternary complex model and with observed receptor phenomenon. This alternative model does not merely provide a new set of formulae but leads to a new philosophical outlook and more readily accommodates experimental observations. The ternary complex model implies that, HRG being responsible for efficient G protein activation, it should be as stable as possible. In contrast, the enzyme model suggests that although a limited stabilization of HRG facilitates GDP release, HRG should not be "too stable" as this might trap the G protein in an inactive state and actually hinder G protein activation. The two models also differ completely in the definition of the receptor "active state": the ternary complex model implies that the active state corresponds to a single active receptor conformation (HRG); in contrast, the catalytic model predicts that the active receptor state is mobile, switching smoothly through various conformations with high and low affinities for agonists (HR, HRG, HRGGDP, HRGGTP, etc.).

  13. Anticoagulation in patients with impaired renal function and with haemodialysis. Anticoagulant effects, efficacy, safety, therapeutic options.

    Science.gov (United States)

    Harenberg, J; Hentschel, V A-T; Du, S; Zolfaghari, S; Krämer, R; Weiss, C; Krämer, B K; Wehling, M

    2015-01-01

    Patients with impaired renal function are exposed to an increased risk for bleeding complications depending on the amount of the anticoagulant eliminated by the kidneys. The elimination of unfractionated heparins, vitamin K antagonists and argatroban is only minimally influenced by a reduced renal function. Low-molecular weight heparins, fondaparinux, danaparoid, hirudins and non-vitamin K antagonist oral anticoagulants (NOAC) cause a variably increased bleeding risk in renal impairment. Dose reductions are recommended for all of these anticoagulants in renal impairment, some are even contraindicated at certain levels of renal impairment. Their benefit over the conventional anticoagulants is preserved if renal dosing is employed. For end-stage renal disease patients specific treatment regimens are required. PMID:25405246

  14. Expanding horizons of anticoagulant therapy: Dabigatran etexilate a novel oral anticoagulant

    Directory of Open Access Journals (Sweden)

    Pradeep Jadhav

    2013-10-01

    Full Text Available Thrombo-embolic disease is a major challenging clinical problem associated with significant mortality and morbidity. Anticoagulation with the existing heparin products and vitamin K antagonist (VKA anticoagulants are still the mainstay of management. However, due to the risk of bleeding and well-documented drawbacks, the quest for a novel oral anticoagulant has led to the clinical development of dabigatran etexilate. Dabigatran etexilate is a direct thrombin (IIa inhibitor which has recently been approved in India for prevention of venous thromboembolic events (VTE in patients who have undergone major orthopaedic (total knee or hip replacement surgery and for prevention of stroke, systemic embolism and reduction of vascular mortality in adult patients with atrial fibrillation. Thus dabigatran etexilate is a promising alternative to the current heparin products and VKAs in patients who require long-term oral anticoagulation. [Int J Basic Clin Pharmacol 2013; 2(5.000: 663-667

  15. Serum paraoxonase activity and protein thiols in patients with hyperlipidemia

    Institute of Scientific and Technical Information of China (English)

    Mungli Prakash; Jeevan K Shetty; Sudeshna Tripathy; Pannuri Vikram; Manish Verma

    2009-01-01

    Objective: In the present study we evaluated the paraoxonase activity and protein thiols level in south Indian population with newly diagnosed hyperlipidemia. Methods: The study was conducted on 55 newly diagnosed hyperlipidemic pa-tients and 57 healthy controls. Serum paraoxonase activity and protein thiols were estimated by spectrophotometeric method and lipid profile by enzymatic kinetic assay method. Results: Serum paraoxonase activity, protein thiols and high density lipoprotein levels were low and total cholesterol, triglycerides and low density lipoprutein levels were high in patients with hyperlipidemia compared to healthy controls ( P < 0.01 ). Serum paranxonase activity correlated positively with protein thiols and high density lipoprotein (P<0.01). Conclusion: Decreased paraoxonase activity and protein thiols were found in patients with hyperlipi-demia. This may indicate the susceptibility of this population to accelerated atherogenesis and protein oxidation.

  16. Sulfur activation-related extracellular proteins of Acidithiobacillus ferrooxidans

    Institute of Scientific and Technical Information of China (English)

    ZHANG Cheng-gui; ZHANG Rui-yong; XIA Jin-lan; ZHANG Qian; NIE Zhen-yuan

    2008-01-01

    The fractions of the extracellular proteins of Acidithiobacillus ferrooxidans grown on two different energy substrates,elemental sulfur and ferrous sulfate,were selectively prepared with hot water treatment and distinctly shown by two-dimensional gel electrophoresis.Some protein spots with apparently higher abundance in sulfur energy substrate than in ferrous sulfate energy substrate were identified by using MALDI-TOF/TOF.Based on peptide mass fingerprints and bioinformatical analysis,the extracellular proteins were classified according to their functions as conjugal transfer protein,pilin,vacJ lipoprotein,polysaccharide deacetylase family protein,Ser/Thr protein phosphatase family protein and hypothetical proteins.Several extracellular proteins were found abundant in thiol groups and with CXXC functional motif,these proteins may be directly involved in the sulfur activation by use of their thiol group (Pr-SH) to bond the elemental sulfur.

  17. Active Nuclear Import of Membrane Proteins Revisited

    NARCIS (Netherlands)

    Laba, Justyna K; Steen, Anton; Popken, Petra; Chernova, Alina; Poolman, Bert; Veenhoff, Liesbeth M

    2015-01-01

    It is poorly understood how membrane proteins destined for the inner nuclear membrane pass the crowded environment of the Nuclear Pore Complex (NPC). For the Saccharomyces cerevisiae proteins Src1/Heh1 and Heh2, a transport mechanism was proposed where the transmembrane domains diffuse through the m

  18. Anticoagulant management in the cardiovascular setting.

    NARCIS (Netherlands)

    Verheugt, F.W.A.

    2012-01-01

    Vitamin K antagonists have been used as oral anticoagulants (OACs) for over five decades, yet their use in real-world practice is problematic primarily because of their narrow therapeutic window, exacerbated by extensive food and drug interactions, necessitating regular coagulation monitoring and do

  19. Safety of anticoagulant treatment in cancer patients

    NARCIS (Netherlands)

    Wilts, Ineke Theodora; Bleker, Suzanne Mariella; Van Es, Nick; Buller, Harry Roger; Di Nisio, Marcello; Kamphuisen, Pieter Willem

    2015-01-01

    Introduction: Patients with cancer are at increased risk of (recurrent) venous thronnboembolism. They are also at increased risk of bleeding. This makes treatment of venous thromboembolisms (VTE) in cancer patients challenging. Areas covered: In this review, we will focus on the safety of anticoagul

  20. TNF Regulates Essential Alternative Complement Pathway Components and Impairs Activation of Protein C in Human Glomerular Endothelial Cells.

    Science.gov (United States)

    Sartain, Sarah E; Turner, Nancy A; Moake, Joel L

    2016-01-15

    Atypical hemolytic uremic syndrome (aHUS) is a thrombotic microangiopathy with severe renal injury secondary to an overactive alternative complement pathway (AP). aHUS episodes are often initiated or recur during inflammation. We investigated gene expression of the surface complement regulatory proteins (CD55, CD59, CD46, and CD141 [thrombomodulin]) and AP components in human glomerular microvascular endothelial cells (GMVECs) and in HUVECs, a frequently used investigational model of endothelial cells. Surface complement regulatory proteins were also quantified by flow cytometry. All experiments were done with and without exposure to IL-1β or TNF. Without cytokine stimulation, we found that GMVECs had greater AP activation than did HUVECs. With TNF stimulation, THBD gene expression and corresponding CD141 surface presence in HUVECs and GMVECs were reduced, and gene expression of complement components C3 (C3) and factor B (CFB) was increased. Consequently, AP activation, measured by Ba production, was increased, and conversion of protein C (PC) to activated PC by CD141-bound thrombin was decreased, in GMVECs and HUVECs exposed to TNF. IL-1β had similar, albeit lesser, effects on HUVEC gene expression, and it only slightly affected GMVEC gene expression. To our knowledge, this is the first detailed study of the expression/display of AP components and surface regulatory proteins in GMVECs with and without cytokine stimulation. In aHUS patients with an underlying overactive AP, additional stimulation of the AP and inhibition of activated PC-mediated anticoagulation in GMVECs by the inflammatory cytokine TNF are likely to provoke episodes of renal failure. PMID:26673143

  1. Pharmacology of anticoagulants used in the treatment of venous thromboembolism.

    Science.gov (United States)

    Nutescu, Edith A; Burnett, Allison; Fanikos, John; Spinler, Sarah; Wittkowsky, Ann

    2016-01-01

    Anticoagulant drugs are the foundation of therapy for patients with VTE. While effective therapeutic agents, anticoagulants can also result in hemorrhage and other side effects. Thus, anticoagulant therapy selection should be guided by the risks, benefits and pharmacologic characteristics of each agent for each patient. Safe use of anticoagulants requires not only an in-depth knowledge of their pharmacologic properties but also a comprehensive approach to patient management and education. This paper will summarize the key pharmacologic properties of the anticoagulant agents used in the treatment of patients with VTE. PMID:26780737

  2. Anticoagulation, ferrotoxicity and the future of translational lung cancer research.

    Science.gov (United States)

    Zacharski, Leo R

    2016-06-01

    Numerous studies have shown that elements of coagulation reactions mediate tumor cell proliferation, motility (invasiveness), tissue remodeling and metastasis. Coagulation activation is virtually a universal feature of human malignancy that differs from the clotting response to injury in that it is self-perpetuating rather than self-attenuating. Coagulation activation participates in tumor matrix deposition and local inflammation, and predicts subsequent cancer risk and adverse cancer outcomes. Several clinical trials of anticoagulants have shown improved outcomes in small cell carcinoma of the lung (SCCL) that have been correlated with assembly on the tumor cells of an intact coagulation pathway. However, variable efficacy of anticoagulant therapy has raised doubts about the coagulation hypothesis. Recently, initiators of coagulation and fibrinolytic pathways have been identified that mediate tumor inception and progression. Notable among these is oxidative stress driven by iron-catalyzed reactive oxygen species that may be the basis for local coagulation activation, tumor matrix deposition, inflammation and aberrant properties characteristic of the malignant phenotype. Recognition of important biological characteristics of individual tumor types, disease stage, choice of standard therapy including chemotherapy and the iron status of the host may clarify mechanisms. All of these are subject to modification based on controlled clinical trial design. Further tests of the coagulation hypothesis may lead to novel, low cost and relatively non-toxic approaches to treatment of malignancy including lung cancer that contrast with certain current cancer treatment paradigms. PMID:27413710

  3. Anticoagulation, ferrotoxicity and the future of translational lung cancer research

    Science.gov (United States)

    2016-01-01

    Numerous studies have shown that elements of coagulation reactions mediate tumor cell proliferation, motility (invasiveness), tissue remodeling and metastasis. Coagulation activation is virtually a universal feature of human malignancy that differs from the clotting response to injury in that it is self-perpetuating rather than self-attenuating. Coagulation activation participates in tumor matrix deposition and local inflammation, and predicts subsequent cancer risk and adverse cancer outcomes. Several clinical trials of anticoagulants have shown improved outcomes in small cell carcinoma of the lung (SCCL) that have been correlated with assembly on the tumor cells of an intact coagulation pathway. However, variable efficacy of anticoagulant therapy has raised doubts about the coagulation hypothesis. Recently, initiators of coagulation and fibrinolytic pathways have been identified that mediate tumor inception and progression. Notable among these is oxidative stress driven by iron-catalyzed reactive oxygen species that may be the basis for local coagulation activation, tumor matrix deposition, inflammation and aberrant properties characteristic of the malignant phenotype. Recognition of important biological characteristics of individual tumor types, disease stage, choice of standard therapy including chemotherapy and the iron status of the host may clarify mechanisms. All of these are subject to modification based on controlled clinical trial design. Further tests of the coagulation hypothesis may lead to novel, low cost and relatively non-toxic approaches to treatment of malignancy including lung cancer that contrast with certain current cancer treatment paradigms.

  4. A new era of oral anticoagulation in atrial fibrillation: implications in clinical practice.

    Science.gov (United States)

    Kasmeridis, Charalampos; Lip, Gregory Y; Apostolakis, Stavros

    2013-02-01

    For > 50 years, vitamin K antagonists were the only available oral drugs for the prevention of thromboembolism in patients with atrial fibrillation. Recently, new oral anticoagulants (the direct thrombin inhibitor dabigatran and the direct activated factor X (factor Xa) inhibitors rivaroxaban and apixaban) have completed phase 3 clinical trials for the same indications. The direct factor Xa inhibitor apixaban was approved by the US Food and Drug Administration in December 2012. In this article, we provide a comprehensive assessment of the safety and efficacy of the new oral anticoagulants. We focus primarily on the balance between thromboembolic and hemorrhagic risk and the implications of such risks in clinical practice. Bleeding and thromboembolic risk estimation tools and their roles in the correct utilization of new oral anticoagulation are also discussed. PMID:23466968

  5. Antioxidant activity of whey protein hydrolysates in milk beverage system

    OpenAIRE

    Mann, Bimlesh; Kumari, Anuradha; Kumar, Rajesh; Sharma, Rajan; Prajapati, Kishore; Mahboob, Shaik; Athira, S.

    2014-01-01

    The aim of the present study was to evaluate the antioxidant activity of flavoured milk enriched with antioxidative whey protein hydrolysates (WPHs) by radical scavenging method. Whey protein concentrate (WPC) was hydrolyzed by using three commercial proteases; flavouzyme, alcalase and corolase PP and these WPHs were analyzed for degree of hydrolysis and antioxidant activity. The antioxidant activities of these WPHs were evaluated using ABTS method. Trolox equivalent antioxidant activity of a...

  6. The protein C pathway in cancer metastasis.

    Science.gov (United States)

    Spek, C Arnold; Arruda, Valder R

    2012-04-01

    Cancer is frequently associated with activation of blood coagulation, which in turn has been suggested to promote tumor growth and metastasis. Indeed, low molecular weight heparin treatment significantly prolongs the survival of a wide variety of patients with cancer. Based on this notion that anticoagulant treatment seems to benefit cancer patients, recent experiments aimed to elucidate the importance of the natural anticoagulant protein C pathways in cancer progression. Interestingly, these experiments showed that the repeated administration of exogenous activated protein C limits cancer cell extravasation in experimental animal models. In line, reducing endogenous activated protein C activity dramatically increased the number of experimental metastasis. These data thus strongly suggest that exogenous activated protein C administration may be a novel therapeutic avenue to limit cancer metastasis thereby prolonging overall survival of cancer patients. The current review provides an overview of recent data on the role of the protein C pathway in cancer metastasis. It discusses the potential of activated protein C as a novel target to reduce cancer progression, it points to several limitations of activated protein C administration in the setting of cancer cell metastasis and it suggest zymogen protein C as an attractive alternative. PMID:22682140

  7. Bivalirudin as an adjunctive anticoagulant to heparin in the treatment of heparin resistance during cardiopulmonary bypass-assisted cardiac surgery.

    Science.gov (United States)

    McNair, E; Marcoux, J-A; Bally, C; Gamble, J; Thomson, D

    2016-04-01

    Heparin resistance (unresponsiveness to heparin) is characterized by the inability to reach acceptable activated clotting time values following a calculated dose of heparin. Up to 20% of the patients undergoing cardiothoracic surgery with cardiopulmonary bypass using unfractionated heparin (UFH) for anticoagulation experience heparin resistance. Although UFH has been the "gold standard" for anticoagulation, it is not without its limitations. It is contraindicated in patients with confirmed heparin-induced thrombocytopenia (HIT) and heparin or protamine allergy. The safety and efficacy of the use of the direct thrombin inhibitor bivalirudin for anticoagulation during cardiac surgery has been reported. However, there have been no reports on the treatment of heparin resistance with bivalirudin during CPB. In this review, we report the favorable outcome of our single-center experience with the alternative use of bivalirudin in the management of anticoagulation of heparin unresponsive patients undergoing coronary artery bypass graft surgery. PMID:25934498

  8. Lupus-anticoagulant testing at NOAC trough levels.

    Science.gov (United States)

    Ratzinger, Franz; Lang, Mona; Belik, Sabine; Jilma-Stohlawetz, Petra; Schmetterer, Klaus G; Haslacher, Helmuth; Perkmann, Thomas; Quehenberger, Peter

    2016-08-01

    Non-vitamin K antagonist oral anticoagulants (NOAC), including rivaroxaban, apixaban or dabigatran, regularly show relevant effects on coagulation tests, making the interpretation of results difficult. The aim of this study was to evaluate possible interferences of NOACs in trough level concentrations in lupus anticoagulant (LA) testing. Citrate plasma specimens of 30 healthy volunteers were spiked with rivaroxaban, apixaban or dabigatran in four plasma concentration levels at or below trough NOAC levels. The NOAC concentration was measured using dedicated surrogate concentration tests and a stepwise diagnostic procedure for LA-testing was applied using screening, mixing and confirmatory testing. Results were compared to NOAC-free specimens. Starting with a plasma concentration of 12.5 ng/ml, dabigatran-spiked specimens showed significant prolongations in the lupus anticoagulant-sensitive activated partial thromboplastin time (aPTT-LA) as well as in the Dilute Russell viper venom time (dRVVT), leading to 43.3 % false positives in confirmatory testing in the dRVVT. In contrast, rivaroxaban, beginning with 7.5 ng/ml, exclusively affected dRVVT-based tests. In confirmatory tests, 30.0 % of rivaroxaban-spiked specimens showed false positive results. Starting with 18.75 ng/ml apixaban, a significant prolongation of the dRVVT and up to 20.7 % false positives in confirmatory tests were found. In contrast to other NOACs tested, apixaban did not present with a dose-dependent increase of the dRVVT ratio. In conclusion, the rate of false positive results in LA-testing is unacceptably high at expected trough levels of NOACs. Even at plasma concentrations below the LLOQ of commercially available surrogate tests, LA testing is best avoided in patients with NOAC therapy.

  9. Purification, renaturation, and reconstituted protein kinase activity of the Sendai virus large (L) protein: L protein phosphorylates the NP and P proteins in vitro.

    OpenAIRE

    Einberger, H; Mertz, R; Hofschneider, P H; Neubert, W J

    1990-01-01

    Sodium dodecyl sulfate-solubilized Sendai virus large (L) protein was highly purified by a one-step procedure, using hydroxylapatite column chromatography. Monoclonal antibodies addressed to the carboxyl-terminal amino acid sequence of the L protein were used for monitoring L protein during purification. By removing sodium dodecyl sulfate from purified L protein, a protein kinase activity was successfully renatured. P and NP proteins served as its substrates. After immunoprecipitation with an...

  10. Role of Antiplatelet Therapy and Anticoagulation in Nonischemic Cardiomyopathy.

    Science.gov (United States)

    Carazo, Matthew; Berger, Jeffrey S; Reyentovich, Alex; Katz, Stuart D

    2016-01-01

    Heart failure continues to be a leading cause of morbidity and mortality throughout the United States. The pathophysiology of heart failure involves the activation of complex neurohormonal pathways, many of which mediate not only hypertrophy and fibrosis within ventricular myocardium and interstitium, but also activation of platelets and alteration of vascular endothelium. Platelet activation and vascular endothelial dysfunction may contribute to the observed increased risk of thromboembolic events in patients with chronic heart failure. However, current data from clinical trials do not support the routine use of chronic antiplatelet or oral anticoagulation therapy for ambulatory heart failure patients without other indications (atrial fibrillation and/or coronary artery disease) as the risk of bleeding seems to outweigh the potential benefit related to reduction in thromboembolic events. In this review, we consider the potential clinical utility of targeting specific pathophysiological mechanisms of platelet and vascular endothelial activation to guide clinical decision making in heart failure patients. PMID:26501990

  11. Protein determination in seeds by proton activation

    Science.gov (United States)

    Morales, J. R.; Dinator, M. I.; Cerda, P.

    1989-04-01

    A proton beam of 6.6 MeV has been used to produce 11C and 13N in Araucaria Araucana seeds. Their positron decay allows determination of the N/C ratio. In seeds the nitrogen content is associated to proteins while carbon is spread in the organic material. Samples were irradiated for about 10 min with a beam intensity of 5 nA on areas of 1 mm 2. Slices of the seed were radially explored, showing a larger concentration of protein in the center.

  12. Protein determination in seeds by proton activation

    Energy Technology Data Exchange (ETDEWEB)

    Morales, J.R.; Dinator, M.I. (Chile Univ., Santiago (Chile). Lab. de Fisica); Cerda, P. (Bio-Bio Univ., Chillan (Chile))

    1989-04-01

    A proton beam of 6.6 MeV has been used to produce /sup 11/C and /sup 13/N in Araucaria Araucana seeds. Their positron decay allows determination of the N/C ratio. In seeds the nitrogen content is associated to proteins while carbon is spread in the organic material. Samples were irradiated for about 10 min with a beam intensity of 5 nA on areas of 1 mm/sup 2/. Slices of the seed were radially explored, showing a larger concentration of protein in the center. (orig.).

  13. Low anticoagulant heparin oligosaccharides as inhibitors of BACE-1, the Alzheimer's β-secretase.

    Science.gov (United States)

    Zhang, Xiao; Zhao, Xiaoliang; Lang, Yinzhi; Li, Qinying; Liu, Xiaoxiao; Cai, Chao; Hao, Jiejie; Li, Guoyun; Yu, Guangli

    2016-10-20

    Heparin (HP) is a promising agent for anti-Alzheimer's disease (AD), but its anticoagulant activity limits its applications. So a low anticoagulant heparin (LAH) with anti-AD effect is needed. A novel LAH and heparan sulfate (HS) were purified from crude porcine intestinal heparin. Their structures were characterized by nuclear magnetic resonance and liquid chromatography-mass spectrometry. LAH had a relatively high degree of sulfation, but lower than that of HP. 3-O-Sulfated-containing glucosamine residues further confirmed the low anticoagulant activity of LAH. Sixteen oligosaccharides of LAH and HS were prepared and assigned. Evaluation of anti-BACE-1 activities suggested that their potencies were positively correlated with degree of sulfation and polymerization of oligosaccharides. Besides, LAH-derived hexa- to dodecasaccharides was promised to be administrated in vitro as BACE-1 inhibitors. This study presented ideal BACE-1 inhibitors, LAH-derived oligosaccharides, with virtually no anticoagulant activities, which were promised to be excellent leads for treatment of AD. PMID:27474542

  14. A simple method to discriminate between beta(2)-glycoprotein I- and prothrombin-dependent lupus anticoagulants

    NARCIS (Netherlands)

    Simmelink, MJA; Derksen, RHWM; Arnout, J; De Groot, PG

    2003-01-01

    Lupus anticoagulants (LAC) are a heterogeneous group of autoantibodies that prolong phospholipid-dependent clotting assays. The autoantibodies that cause LAC activity are predominantly directed against beta(2)-glycoprotein I (beta(2)GPI) or prothrombin. In the present study, we describe a method to

  15. In vitro anticoagulation monitoring of low-molecular-weight heparin

    Institute of Scientific and Technical Information of China (English)

    WANG Jian-qi; SHI Xu-bo; YANG Jin-gang; HU Da-yi

    2009-01-01

    Background Although low-molecular-weight heparin has replaced unfractionated heparin to become the primary anticoagulation drug for treatment of acute coronary syndrome, there is no convenient bedside monitoring method. We explored the best laboratory monitoring method of low-molecular-weight heparins (enoxapadn, dalteparin, and nadroparin) by use of the Sonoclot coagulation analyzer to monitor the activated clotting time.Methods Atotal of 20 healthy volunteers were selected and 15 ml of fasting venous blood samples were collected and incubated. Four coagulants, kaolin, diatomite, glass bead, and magnetic stick, were used to determine the activated clotting time of the low-molecular-weight heparins at different in vitro anti-Xa factor concentrations. A correlation analysis was made to obtain the regression equation. The activated clotting time of the different low-molecular-weight heparins with the same anti-Xa factor concentration was monitored when the coagulant glass beads were applied. Results The activated clotting time measured using the glass beads, diatomite, kaolin, and magnetic stick showed a linear correlation with the concentration of nadroparin (r= 0.964, 0.966, 0.970, and 0.947, respectively). The regression equation showed that the linear slopes of different coagulants were significantly different (glass beads 230.03 s/IU,diatomite 89.91 s/IU, kaolin 50.87 s/IU, magnetic stick could not be calculated). When the concentration of the anti-Xa factor was the same for different low-molecular-weight heparins, the measured activated clotting time was different after the application of the glass bead coagulant.Conclusions The glass bead coagulant is most feasible for monitoring the in vitro anticoagulation activity of nadroparin.The different effects of different low-molecular-weight heparins on the activated clotting time may be related to the different anti-Ila activities.

  16. Hydrodynamic collective effects of active proteins in biological membranes

    CERN Document Server

    Koyano, Yuki; Mikhailov, Alexander S

    2016-01-01

    Lipid bilayers forming biological membranes are known to behave as viscous 2D fluids on submicrometer scales; usually they contain a large number of active protein inclusions. Recently, it has been shown [Proc. Nat. Acad. Sci. USA 112, E3639 (2015)] that such active proteins should in- duce non-thermal fluctuating lipid flows leading to diffusion enhancement and chemotaxis-like drift for passive inclusions in biomembranes. Here, a detailed analytical and numerical investigation of such effects is performed. The attention is focused on the situations when proteins are concentrated within lipid rafts. We demonstrate that passive particles tend to become attracted by active rafts and are accumulated inside them.

  17. [New orally anticoagulants and brain stroke].

    Science.gov (United States)

    Kaczorowska, Beata; Pawełczyk, Małgorzata; Przybyła, Monika

    2016-05-26

    Brain stroke is a grave society problem. About 20% ischemic strokes are cardiac related problems. Atrial fibrillation (AF) is the most common cause of ischemic strokes. Decision to deploy anticoagulant treatment with AF patient depends on bleeding and thrombo-embolic risk which summerise scale CHA2DS2VASc and HAS-BLED. Past recent years in AF treatment anticoagulants from the group of vitamin K antagonist were used. At present in brain stroke prevention and systemic emboilment, new oral anticoagulants (NOA) which weren't worst than vitamin K antagonists, and they are recomendet in most cases of AF unrelated with heart valve defets. Useing NOA causes lower risk of bleeding, including intracranial heamorrhage. It is believed that this is related to the selective inhibition of specific coagulation factors, and respect other hemostatic mechanisms. Results from clinical studies NOA are encouraging, but still lacks clear answers regarding, among other things: long-term safety of treatment and economically viable in everyday clinical practice. In addition, to date there is no specific antidote for this group of drugs. PMID:27234866

  18. [New oral anticoagulants in atrial fibrillation].

    Science.gov (United States)

    Veltkamp, R; Hacke, W

    2011-02-01

    Atrial fibrillation (AF) causes at least 20% of all ischemic strokes. In large randomized trials of primary and secondary stroke prevention, anticoagulation with vitamin K antagonists (VKA) protected much more efficiently than antiplatelet agents against stroke. Because of the problematic pharmacological properties of VKA only part of the AF patients are currently being treated with oral anticoagulants (OAK). The targeted development of specific oral inhibitors of the central coagulation factors thrombin and factor Xa allows reliable anticoagulation without regular coagulation monitoring. In the present review, pharmacological properties of the different agents are compared. Of the four large randomized phase 3 studies in AF (RELY, ROCKET-AF, ARISTOTLE, ENGAGE-AF) with the primary efficacy endpoint stroke and systemic embolism, the published data from the RELY trial indicate a superior efficacy of dabigatran etexilate (2 × 150 mg/day) and a lower risk of intracranial hemorrhage compared to warfarin. Favorable preliminary results have been demonstrated for the factor Xa inhibitor rivaroxaban. Apixaban was more efficacious than ASA and had a similar risk of hemorrhage in the AVERROES study. Thus, the available data suggest a favorable benefit-risk ratio for the new substances in addition to improved patient comfort. Currently unresolved issues relate to the verification of patient adherence by suitable coagulation tests and to the emergency coagulation diagnostics and therapy in acute ischemic or hemorrhagic strokes under the new OAC.

  19. Antioxidant activities of protein hydrolysates obtained from the housefly larvae.

    Science.gov (United States)

    Zhang, Huan; Wang, Pan; Zhang, Ai-Jun; Li, Xuan; Zhang, Ji-Hong; Qin, Qi-Lian; Wu, Yi-Jun

    2016-09-01

    The housefly is an important resource insect and the housefly larvae are ideal source of food additives. The housefly larvae protein hydrolysates were obtained by enzymatic hydrolysis by alcalase and neutral proteinase. Their antioxidant activities were investigated, including the superoxide and hydroxyl radicalscavenging activity, 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity, reducing power and metal chelating activity. The antioxidant activities of both hydrolysates increased with their increasing concentrations. The alcalase hydrolysate (AH) showed higher scavenging activities against hydroxyl radical and superoxide anion radical at low concentrations and higher metal-chelating activity than the neutral proteinase hydrolysate (NPH). The NPH exhibited higher scavenging activity against DPPH free radical and higher reducing power than the AH. Both hydrolysates showed more than 50% superoxide anion radical-scavenging activity at 10 μg/mL. These results indicate that both housefly larvae protein hydrolysates display high antioxidant activities and they could serve as potential natural antioxidant food additives. PMID:27630047

  20. Protein stability and enzyme activity at extreme biological temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Feller, Georges, E-mail: gfeller@ulg.ac.b [Laboratory of Biochemistry, Centre for Protein Engineering, Institute of Chemistry B6a, University of Liege, B-4000 Liege (Belgium)

    2010-08-18

    Psychrophilic microorganisms thrive in permanently cold environments, even at subzero temperatures. To maintain metabolic rates compatible with sustained life, they have improved the dynamics of their protein structures, thereby enabling appropriate molecular motions required for biological activity at low temperatures. As a consequence of this structural flexibility, psychrophilic proteins are unstable and heat-labile. In the upper range of biological temperatures, thermophiles and hyperthermophiles grow at temperatures > 100 {sup 0}C and synthesize ultra-stable proteins. However, thermophilic enzymes are nearly inactive at room temperature as a result of their compactness and rigidity. At the molecular level, both types of extremophilic proteins have adapted the same structural factors, but in opposite directions, to address either activity at low temperatures or stability in hot environments. A model based on folding funnels is proposed accounting for the stability-activity relationships in extremophilic proteins. (topical review)

  1. Antioxidant activity of black bean (Phaseolus vulgaris L.) protein hydrolysates

    OpenAIRE

    Jarine Amaral do EVANGELHO; Jose de J. BERRIOS; Vânia Zanella PINTO; Mariana Dias ANTUNES; Nathan Levien VANIER; Elessandra da Rosa ZAVAREZE

    2016-01-01

    Abstract The objective of this work was to study the effect of enzymatic hydrolysis of black bean protein concentrate using different enzymes. Bean proteins were extracted and hydrolyzed over a period of 120 min using the enzymes pepsin or alcalase. The protein hydrolysates’ molecular weight was assayed by electrophoresis and the antioxidant activity was evaluated by the capturing methods of free radicals ABTS●+ and DPPH. Electrophoretic results showed that the bands above 50 kDa disappeared,...

  2. Controlled Activation of Protein Rotational Dynamics Using Smart Hydrogel Tethering

    Energy Technology Data Exchange (ETDEWEB)

    Beech, Brenda M.; Xiong, Yijia; Boschek, Curt B.; Baird, Cheryl L.; Bigelow, Diana J.; Mcateer, Kathleen; Squier, Thomas C.

    2014-09-05

    Stimulus-responsive hydrogel materials that stabilize and control protein dynamics have the potential to enable a range of applications to take advantage of the inherent specificity and catalytic efficiencies of proteins. Here we describe the modular construction of a hydrogel using an engineered calmodulin (CaM) within a polyethylene glycol (PEG) matrix that involves the reversible tethering of proteins through an engineered CaM-binding sequence. For these measurements, maltose binding protein (MBP) was isotopically labeled with [13C] and [15N], permitting dynamic structural measurements using TROSY-HSQC NMR spectroscopy. Upon initial formation of hydrogels protein dynamics are suppressed, with concomitant increases in protein stability. Relaxation of the hydrogel matrix following transient heating results in the activation of protein dynamics and restoration of substrate-induced large-amplitude domain motions necessary for substrate binding.

  3. Mitogen activated protein kinases: a role in inflammatory bowel disease?

    DEFF Research Database (Denmark)

    Broom, O J; Widjaya, B; Troelsen, J;

    2009-01-01

    Since their discovery more than 15 years ago, the mitogen activated protein kinases (MAPK) have been implicated in an ever-increasingly diverse array of pathways, including inflammatory signalling cascades. Inflammatory bowel diseases (IBD), such as ulcerative colitis and Crohn's disease...... and their related signalling proteins in influencing the progression of IBD....

  4. Dietary Protein Considerations to Support Active Aging

    OpenAIRE

    Wall, Benjamin T.; Cermak, Naomi M.; van Loon, Luc J. C.

    2014-01-01

    Given our rapidly aging world-wide population, the loss of skeletal muscle mass with healthy aging (sarcopenia) represents an important societal and public health concern. Maintaining or adopting an active lifestyle alleviates age-related muscle loss to a certain extent. Over time, even small losses of muscle tissue can hinder the ability to maintain an active lifestyle and, as such, contribute to the development of frailty and metabolic disease. Considerable research focus has addressed the ...

  5. Coactivator p100 protein enhances histone acetyltransferase activity of CBP

    Institute of Scientific and Technical Information of China (English)

    JIE YANG; HONG BAI; Li JIE DONG; JIE SHAO; OLLI SILVENNOINEN; ZHI YAO

    2006-01-01

    Human p100 protein consists of four repeated domains of staphylococcal nuclease (SN)-like domain, as well as a tudor (TD) domain thereafter. We have previously shown that the SN-like domain of p100 interacted with STAT6 and the large subunit of RNA pol Ⅱ, resulting in the enhancement of STAT6-mediated gene transcriptional activation. Here, we show that SN-like domain also interacted with CREB binding protein (CBP) and directly enhanced the acetyl transferase activity of CBP on histone. On the other hand, overexpression of CBP alone had no ability to significantly increase STAT6-dependent transcriptional activation, however, together with p100 protein, sufficiently enhanced the activation of transcription which was in line with the previous result that p100 protein bridged STAT6 with CBP.

  6. Depletion of WRN protein causes RACK1 to activate several protein kinase C isoforms

    DEFF Research Database (Denmark)

    Massip, L; Garand, C; Labbé, A;

    2010-01-01

    show that a knock down of the WRN protein in normal human fibroblasts induces phosphorylation and activation of several protein kinase C (PKC) enzymes. Using a tandem affinity purification strategy, we found that WRN physically and functionally interacts with receptor for activated C-kinase 1 (RACK1...... activity in vitro. Interestingly, knocking down RACK1 increased the cellular frequency of DNA breaks. Depletion of the WRN protein in return caused a fraction of nuclear RACK1 to translocate out of the nucleus to bind and activate PKCdelta and PKCbetaII in the membrane fraction of cells. In contrast......), a highly conserved anchoring protein involved in various biological processes, such as cell growth and proliferation. RACK1 binds strongly to the RQC domain of WRN and weakly to its acidic repeat region. Purified RACK1 has no impact on the helicase activity of WRN, but selectively inhibits WRN exonuclease...

  7. Comprehensive characterization of anticoagulant rodenticides in sludge by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Gómez-Canela, Cristian; Lacorte, Silvia

    2016-08-01

    The occurrence of 10 commonly used anticoagulant rodenticides in centrifuged sludge of 27 wastewater treatment plants was evaluated using solid-liquid extraction (SLE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Activated carbon, alumina, and Florisil cartridges with methanol/dichloromethane as eluting solvents were tested in combination with primary-secondary amine (PSA) to optimize an efficient sample cleanup. PSA in combination with Florisil was the best methodology to extract anticoagulant rodenticides in sludge providing recoveries between 42 ± 0.5 and 100 ± 2 %. Warfarin, bromadiolone, ferulenol, and coumachlor were the most ubiquitous compounds in sludge at concentrations up to 84.2 ng g(-1) for the latter. Coumatetralyl, dicoumarol, and brodifacoum were detected sporadically at levels between 6.1 and 17.4 ng g(-1). On the contrary, acenocoumarol, difenacoum, and flocoumafen were not detected in any sample. Finally, we estimated the amount of anticoagulant rodenticides discharged via sludge in order to determine the potential impact to agricultural soil according to different sludge usage practices in the region investigated. This study demonstrates that anticoagulant rodenticides are accumulated in sludge during activated sludge treatment and that the application of sludge as fertilizers may pose a future environmental risk, if not controlled. PMID:27146526

  8. Purification and characterization of an anticoagulant oligopeptide from Whitmania pigra Whitman

    Directory of Open Access Journals (Sweden)

    Xiaobei Zheng

    2015-01-01

    Full Text Available Background: Dried Whitmania pigra is used for the treatment of cardiovascular and cerebrovascular diseases in traditional Chinese medicine and hot water and alcohol extracts also have anticogulant activity. However, a lower molecular weight and more stable anticogulant is needed. Objective: The objective of the following study is to purify and characterize of an anticoagulant oligopeptide from Hirudo (Whitmania pigra Whitman. Materials and Methods: Gel filtration on Sephadex G 50, ion exchange on diethylaminoethyl cellulose, and semi prepared high performance liquid chromatography were used to purify Hirudo. Automated coagulation analyzer was used for evaluating anticoagulant activity. Molecular weight was measured by Matrix assisted laser desorption ionization time of flight mass spectrometry. Amino acid sequence of the oligopeptide was measured by amino acid sequence analyzer. Results: A new anticoagulant, named whitide, isolated from Hirudo was purified, with a molecular weight 1997.1 Da. Amino acid sequence of the oligopeptide was identified as Gly-Pro-ALa-Gly-Hyp-Val-Gly-Ala-Hyp-Gly-Gly-Hyp-Gly-Val-Arg-Gly-Leu-Hyp-Gly-Asp-Arg-Gly. The results revealed that its amino acid sequence had strong homology to various types of collagen. Conclusion: Whitide might be an orally anticoagulant for its hot and trypsin stable.

  9. Anticoagulation for the Acute Management of Ischemic Stroke

    OpenAIRE

    Robinson, Austin A.; Ikuta, Kevin; Soverow, Jonathan

    2014-01-01

    Few prospective studies support the use of anticoagulation during the acute phase of ischemic stroke, though observational data suggest a role in certain populations. Depending on the mechanism of stroke, systemic anticoagulation may prevent recurrent cerebral infarction, but concomitantly carries a risk of hemorrhagic transformation. In this article, we describe a case where anticoagulation shows promise for ischemic stroke and review the evidence that has discredited its use in some circums...

  10. New anticoagulants for the prevention of venous thromboembolism

    OpenAIRE

    Becattini, Cecilia

    2010-01-01

    Cecilia Becattini, Alessandra Lignani, Giancarlo AgnelliInternal and Cardiovascular Medicine and Stroke Unit, University of Perugia, ItalyAbstract: Anticoagulant drugs have an essential role in the prevention and treatment of thromboembolic diseases. Currently available anticoagulants substantially reduce the incidence of thromboembolic events in a number of clinical conditions. However, these agents have limitations that strengthen the case for the development of new anticoagulants. An ideal...

  11. Contemporary anticoagulation therapy in patients undergoing percutaneous intervention.

    Science.gov (United States)

    Bhatty, Shaun; Ali, Asghar; Shetty, Ranjith; Sumption, Kevin F; Topaz, On; Jovin, Ion S

    2014-04-01

    The proper use of anticoagulants is crucial for ensuring optimal patient outcomes post percutaneous interventions in the cardiac catheterization laboratory. Anticoagulant agents such as unfractionated heparin, a thrombin inhibitor; low-molecular weight heparins, predominantly Factor Xa inhibitors; fondaparinux, a Factor Xa inhibitor and bivalirudin, a direct thrombin inhibitor have been developed to target various steps in the coagulation cascade to prevent formation of thrombin. Optimal anticoagulation achieves the correct balance between thrombosis and bleeding and is related to optimal outcomes with minimal complications. This review will discuss the mechanisms and appropriate use of current and emerging anticoagulant therapies used during percutaneous interventions. PMID:24506409

  12. Anti-inflammatory, anticoagulant and antioxidant effects of aqueous extracts from Moroccan thyme varieties

    Institute of Scientific and Technical Information of China (English)

    Tarik; Khouya; Mhamed; Ramchoun; Abdelbassat; Hmidani; Souliman; Amrani; Hicham; Harnafi; Mohamed; Benlyas; Younes; Filali; Zegzouti; Chakib; Alem

    2015-01-01

    Objective: To evaluate the anti-inflammatory, anticoagulant and antioxidant effects of aqueous extracts of thyme varieties from Moroccan.Methods: The aqueous extracts of tree medicinal plants [Thymus atlanticus(T. atlanticus), Thymus satureioides and Thymus zygis(T. zygis)] were screened for their antioxidant activity using 1,1-diphenyl-2-picrylhydrazyl radical-scavenging, ferric reducing antioxidant power assay, radical scavenging activity method, the inhibition of 2,2’-azobis(2-amidinopropane) dihydrochloride that induces oxidative erythrocyte hemolysis and thiobarbituric acid reactive substances assay. The anti-inflammatory activity of aqueous extracts was evaluated in vivo using croton oil-induced ear edema and carrageenan-induced paw edema in mice and rats, respectively. This extracts were evaluated in vitro for their anticoagulant activity at the different concentrations by partial thromboplastin time and prothrombin time activated. Results: All thyme varieties were found to possess considerable antioxidant activity and potent anti-inflammatory activity in the croton oil-induced edema. Administration of aqueous extracts of two varieties(50 mg/kg)(T. zygis and T. atlanticus) reduced significantly the carrageenaninduced paw edema similar to non-steroidal anti-inflammatory drug(indomethacin, 10 mg/kg). In partial thromboplastin time and prothrombin time tests, T. atlanticus and T. zygis extracts showed the strongest anticoagulant activity. In contrast, Thymus satureioides did not show the anticoagulant activity in these tests. Conclusions: All aqueous extracts possess considerable antioxidant activity and are rich in total polyphenol and flavonoid but they act differently in the process of inflammatory and coagulation studied. This study shows great variability of biological activities in thyme varieties.

  13. Protein kinase D activity controls endothelial nitric oxide synthesis

    OpenAIRE

    Aicart-Ramos, Clara; Sánchez-Ruiloba, Lucía; Gómez-Parrizas, Mónica; Zaragoza, Carlos; Iglesias, Teresa; Rodríguez-Crespo, Ignacio

    2014-01-01

    Vascular endothelial growth factor (VEGF) regulates key functions of the endothelium, such as angiogenesis or vessel repair in processes involving endothelial nitric oxide synthase (eNOS) activation. One of the effector kinases that become activated in endothelial cells upon VEGF treatment is protein kinase D (PKD). Here, we show that PKD phosphorylates eNOS, leading to its activation and a concomitant increase in NO synthesis. Using mass spectrometry, we show that the purified active kinase ...

  14. Regulatory crosstalk by protein kinases on CFTR trafficking and activity

    Science.gov (United States)

    Farinha, Carlos Miguel; Swiatecka-Urban, Agnieszka; Brautigan, David; Jordan, Peter

    2016-01-01

    Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) is a member of the ATP binding cassette (ABC) transporter superfamily that functions as a cAMP-activated chloride ion channel in fluid-transporting epithelia. There is abundant evidence that CFTR activity (i.e. channel opening and closing) is regulated by protein kinases and phosphatases via phosphorylation and dephosphorylation. Here, we review recent evidence for the role of protein kinases in regulation of CFTR delivery to and retention in the plasma membrane. We review this information in a broader context of regulation of other transporters by protein kinases because the overall functional output of transporters involves the integrated control of both their number at the plasma membrane and their specific activity. While many details of the regulation of intracellular distribution of CFTR and other transporters remain to be elucidated, we hope that this review will motivate research providing new insights into how protein kinases control membrane transport to impact health and disease.

  15. Cellular reprogramming through mitogen-activated protein kinases

    Directory of Open Access Journals (Sweden)

    Justin eLee

    2015-10-01

    Full Text Available Mitogen-activated protein kinase (MAPK cascades are conserved eukaryote signaling modules where MAPKs, as the final kinases in the cascade, phosphorylate protein substrates to regulate cellular processes. While some progress in the identification of MAPK substrates has been made in plants, the knowledge on the spectrum of substrates and their mechanistic action is still fragmentary. In this focused review, we discuss the biological implications of the data in our original paper (Sustained mitogen-activated protein kinase activation reprograms defense metabolism and phosphoprotein profile in Arabidopsis thaliana; Frontiers in Plant Science 5: 554 in the context of related research. In our work, we mimicked in vivo activation of two stress-activated MAPKs, MPK3 and MPK6, through transgenic manipulation of Arabidopsis thaliana and used phosphoproteomics analysis to identify potential novel MAPK substrates. Here, we plotted the identified putative MAPK substrates (and downstream phosphoproteins as a global protein clustering network. Based on a highly stringent selection confidence level, the core networks highlighted a MAPK-induced cellular reprogramming at multiple levels of gene and protein expression – including transcriptional, post-transcriptional, translational, post-translational (such as protein modification, folding and degradation steps, and also protein re-compartmentalization. Additionally, the increase in putative substrates/phosphoproteins of energy metabolism and various secondary metabolite biosynthesis pathways coincides with the observed accumulation of defense antimicrobial substances as detected by metabolome analysis. Furthermore, detection of protein networks in phospholipid or redox elements suggests activation of downstream signaling events. Taken in context with other studies, MAPKs are key regulators that reprogram cellular events to orchestrate defense signaling in eukaryotes.

  16. Conserved interaction of the papillomavirus E2 transcriptional activator proteins with human and yeast TFIIB proteins.

    OpenAIRE

    Benson, J D; Lawande, R; Howley, P M

    1997-01-01

    Papillomavirus early gene expression is regulated by the virus gene-encoded E2 proteins. The best-characterized E2 protein, encoded by bovine papillomavirus type 1 (BPV-1), has been shown to interact with basal transcription factor IIB (TFIIB) and the TATA binding protein basal transcription factor (N. M. Rank and P. F. Lambert, J. Virol. 69:6323-6334, 1995). We demonstrate that the potent E2 transcriptional activator protein encoded by a gene of human PV type 16 also interacts with TFIIB in ...

  17. The Role of Anticoagulation Clinics in the Era of New Oral Anticoagulants

    Directory of Open Access Journals (Sweden)

    Sophie Testa

    2012-01-01

    Full Text Available Anticoagulation Clinics (ACs are services specialized in management of patients on anticoagulant treatment. At present, ACs manage patients chiefly on antivitamin K antagonists (AVKs, but patient population has already changed in the last few years, because of an increase of treatments with other anticoagulant drugs, which require different management systems. The strong increase in the number of patients at AC, mainly on long-term treatment, has determined the development of web management, through telemedicine systems, improving the quality of life and maintaining the same clinical quality levels. New oral anticoagulants (NOAs have shown to be as effective as AVK antagonists in stroke prevention in atrial fibrillation and for treatment of venous thromboembolism in addition to VTE prophylaxis in orthopaedic surgery, when administered at a fixed dose, but patient adherence and compliance are crucial for good quality treatment. At present, lacking data from the real world, an oversimplification of treatment with NOAs could cause unjustified risks for patients and also a possible future underuse of good drugs. For these reasons the vigilance must be high and ACs can have a crucial role in defining which is the best management for NOA patients and how to do it, as it happened for AVKs.

  18. The role of anticoagulation clinics in the era of new oral anticoagulants.

    Science.gov (United States)

    Testa, Sophie; Paoletti, Oriana; Zimmermann, Anke; Bassi, Laura; Zambelli, Silvia; Cancellieri, Emilia

    2012-01-01

    Anticoagulation Clinics (ACs) are services specialized in management of patients on anticoagulant treatment. At present, ACs manage patients chiefly on antivitamin K antagonists (AVKs), but patient population has already changed in the last few years, because of an increase of treatments with other anticoagulant drugs, which require different management systems. The strong increase in the number of patients at AC, mainly on long-term treatment, has determined the development of web management, through telemedicine systems, improving the quality of life and maintaining the same clinical quality levels. New oral anticoagulants (NOAs) have shown to be as effective as AVK antagonists in stroke prevention in atrial fibrillation and for treatment of venous thromboembolism in addition to VTE prophylaxis in orthopaedic surgery, when administered at a fixed dose, but patient adherence and compliance are crucial for good quality treatment. At present, lacking data from the real world, an oversimplification of treatment with NOAs could cause unjustified risks for patients and also a possible future underuse of good drugs. For these reasons the vigilance must be high and ACs can have a crucial role in defining which is the best management for NOA patients and how to do it, as it happened for AVKs.

  19. Contractions activate hormone-sensitive lipase in rat muscle by protein kinase C and mitogen-activated protein kinase

    DEFF Research Database (Denmark)

    Donsmark, Morten; Langfort, Jozef; Holm, Cecilia;

    2003-01-01

    Intramuscular triacylglycerol is an important energy store and is also related to insulin resistance. The mobilization of fatty acids from this pool is probably regulated by hormone-sensitive lipase (HSL), which has recently been shown to exist in muscle and to be activated by both adrenaline......-induced activation of HSL was abolished by the protein kinase C (PKC) inhibitors bisindolylmaleimide I and calphostin C and reduced 50% by the mitogen-activated protein kinase kinase (MEK) inhibitor U0126, which also completely blocked extracellular signal-regulated kinase (ERK) 1 and 2 phosphorylation. None...... of the inhibitors reduced adrenaline-induced HSL activation in soleus muscle. Both phorbol-12-myristate-13-acetate (PMA), which activates PKC and, in turn, ERK, and caffeine, which increases intracellular Ca2+ without eliciting contraction, increased HSL activity. Activated ERK increased HSL activity in supernatant...

  20. Laboratory determination of old and new targeted anticoagulant agents for prevention of bleeding and thrombotic events in cancer patients.

    Science.gov (United States)

    Harenberg, Job

    2016-04-01

    A two-fold prolongation of activated partial thromboplastin time (APTT) is established as therapeutic range for therapy with unfractionated heparin, hirudin and argatroban. The international normalized ratio (INR) of 2 to 3 is required to maintain anticoagulation in the therapeutic range of vitamin K antagonists. The therapeutic range of anti-factor Xa activity during therapy with low-molecular weight heparins and danaparoid are less well and of direct oral anticoagulants (DOAC) poorly defined. The relation of aPTT and INR values to thrombotic and bleeding events are well established despite a large variation of values in affected patients. The relation of coagulation values of the other anticoagulants to clinical events is open. The value of determination in cancer patients is higher because of the increased risk for thrombotic and bleeding events of this patient group. Several activities are currently undertaken to certify methods for in vitro diagnostic testing for DAOCs. PMID:27067972

  1. A conserved patch of hydrophobic amino acids modulates Myb activity by mediating protein-protein interactions.

    Science.gov (United States)

    Dukare, Sandeep; Klempnauer, Karl-Heinz

    2016-07-01

    The transcription factor c-Myb plays a key role in the control of proliferation and differentiation in hematopoietic progenitor cells and has been implicated in the development of leukemia and certain non-hematopoietic tumors. c-Myb activity is highly dependent on the interaction with the coactivator p300 which is mediated by the transactivation domain of c-Myb and the KIX domain of p300. We have previously observed that conservative valine-to-isoleucine amino acid substitutions in a conserved stretch of hydrophobic amino acids have a profound effect on Myb activity. Here, we have explored the function of the hydrophobic region as a mediator of protein-protein interactions. We show that the hydrophobic region facilitates Myb self-interaction and binding of the histone acetyl transferase Tip60, a previously identified Myb interacting protein. We show that these interactions are affected by the valine-to-isoleucine amino acid substitutions and suppress Myb activity by interfering with the interaction of Myb and the KIX domain of p300. Taken together, our work identifies the hydrophobic region in the Myb transactivation domain as a binding site for homo- and heteromeric protein interactions and leads to a picture of the c-Myb transactivation domain as a composite protein binding region that facilitates interdependent protein-protein interactions of Myb with regulatory proteins. PMID:27080133

  2. A conserved patch of hydrophobic amino acids modulates Myb activity by mediating protein-protein interactions.

    Science.gov (United States)

    Dukare, Sandeep; Klempnauer, Karl-Heinz

    2016-07-01

    The transcription factor c-Myb plays a key role in the control of proliferation and differentiation in hematopoietic progenitor cells and has been implicated in the development of leukemia and certain non-hematopoietic tumors. c-Myb activity is highly dependent on the interaction with the coactivator p300 which is mediated by the transactivation domain of c-Myb and the KIX domain of p300. We have previously observed that conservative valine-to-isoleucine amino acid substitutions in a conserved stretch of hydrophobic amino acids have a profound effect on Myb activity. Here, we have explored the function of the hydrophobic region as a mediator of protein-protein interactions. We show that the hydrophobic region facilitates Myb self-interaction and binding of the histone acetyl transferase Tip60, a previously identified Myb interacting protein. We show that these interactions are affected by the valine-to-isoleucine amino acid substitutions and suppress Myb activity by interfering with the interaction of Myb and the KIX domain of p300. Taken together, our work identifies the hydrophobic region in the Myb transactivation domain as a binding site for homo- and heteromeric protein interactions and leads to a picture of the c-Myb transactivation domain as a composite protein binding region that facilitates interdependent protein-protein interactions of Myb with regulatory proteins.

  3. Organization, Structure and Activity of Proteins in Monolayers

    Energy Technology Data Exchange (ETDEWEB)

    Boucher,J.; Trudel, E.; Methot, M.; Desmeules, P.; Salesse, C.

    2007-01-01

    Many different processes take place at the cell membrane interface. Indeed, for instance, ligands bind membrane proteins which in turn activate peripheral membrane proteins, some of which are enzymes whose action is also located at the membrane interface. Native cell membranes are difficult to use to gain information on the activity of individual proteins at the membrane interface because of the large number of different proteins involved in membranous processes. Model membrane systems, such as monolayers at the air-water interface, have thus been extensively used during the last 50 years to reconstitute proteins and to gain information on their organization, structure and activity in membranes. In the present paper, we review the recent work we have performed with membrane and peripheral proteins as well as enzymes in monolayers at the air-water interface. We show that the structure and orientation of gramicidin has been determined by combining different methods. Furthermore, we demonstrate that the secondary structure of rhodopsin and bacteriorhodopsin is indistinguishable from that in native membranes when appropriate conditions are used. We also show that the kinetics and extent of monolayer binding of myristoylated recoverin is much faster than that of the nonmyristoylated form and that this binding is highly favored by the presence polyunsaturated phospholipids. Moreover, we show that the use of fragments of RPE65 allow determine which region of this protein is most likely involved in membrane binding. Monomolecular films were also used to further understand the hydrolysis of organized phospholipids by phospholipases A2 and C.

  4. G protein activation stimulates phospholipase D signaling in plants

    NARCIS (Netherlands)

    Munnik, T.; Arisz, S.A.; Vrije, de T.; Musgrave, A.

    1995-01-01

    We provide direct evidence for phospholipase D (PLD) signaling in plants by showing that this enzyme is stimulated by the G protein activators mastoparan, ethanol, and cholera toxin. An in vivo assay for PLD activity in plant cells was developed based on the use of a "reporter alcohol" rather than w

  5. Factor H-related proteins determine complement-activating surfaces.

    Science.gov (United States)

    Józsi, Mihály; Tortajada, Agustin; Uzonyi, Barbara; Goicoechea de Jorge, Elena; Rodríguez de Córdoba, Santiago

    2015-06-01

    Complement factor H-related proteins (FHRs) are strongly associated with different diseases involving complement dysregulation, which suggests a major role for these proteins regulating complement activation. Because FHRs are evolutionarily and structurally related to complement inhibitor factor H (FH), the initial assumption was that the FHRs are also negative complement regulators. Whereas weak complement inhibiting activities were originally reported for these molecules, recent developments indicate that FHRs may enhance complement activation, with important implications for the role of these proteins in health and disease. We review these findings here, and propose that FHRs represent a complex set of surface recognition molecules that, by competing with FH, provide improved discrimination of self and non-self surfaces and play a central role in determining appropriate activation of the complement pathway.

  6. Antibodies for detecting and quantifying anticoagulant agents

    OpenAIRE

    Salvador, Juan Pablo; Marco, María Pilar

    2012-01-01

    [EN] The present invention relates to the design of haptens that are structurally related to coumarin oral anticoagulant compounds (COAC), to be used for the production of specific antibodies against said type of substances and the subsequent use thereof for the development of diagnosis tools for use in laboratories or in point-of-care (PoC) devices. In particular, the produced antibodies have been used to develop a diagnosis tool that enables the plasma levels of COAC to be quantified in pat...

  7. Shortfalls using second-generation anticoagulant rodenticides.

    Science.gov (United States)

    Borst, G H A; Counotte, G H M

    2002-03-01

    Second-generation anticoagulant rodenticides can give rise to unexpected casualties in nontarget species in zoos. The first two offspring of a pair of turkey vultures (Cathartes aura) died of brodifacoum toxicosis. The adult birds fed rodenticide-killed mice to their offspring. There are previous case reports of small carnivorous birds (Dacelo novae-guinae and Tockus deckeni) killed eating poisoned (difenacoum and brodifacoum) mice. Even a granivorous species (Rollulus roulroul) died, probably by contamination of its food by cockroaches that transported the rodenticide. PMID:12216801

  8. Vitamin K requirement in Danish anticoagulant-resistant Norway rats (Rattus norvegicus)

    DEFF Research Database (Denmark)

    Markussen, Mette D.; Heiberg, Ann-Charlotte; Nielsen, Robert;

    2003-01-01

    Norway rats, Rattus norvegicus, Denmark, anticoagulant rodenticide resistance, vitamin K requirement......Norway rats, Rattus norvegicus, Denmark, anticoagulant rodenticide resistance, vitamin K requirement...

  9. A Nitric Oxide-Releasing Heparin Conjugate for Delivery of a Combined Antiplatelet/Anticoagulant Agent

    OpenAIRE

    Suchyta, Dakota J.; Handa, Hitesh; Meyerhoff, Mark E.

    2014-01-01

    Heparin is a widely used anticoagulant due to its ability to inhibit key components in the coagulation cascade such as Factor Xa and thrombin (Factor IIa). Its potential to preferentially bind to antithrombin (ATIII) results in a conformational change and activation that leads to the prevention of fibrin formation from fibrinogen and ultimately obstructs a hemostatic plug from forming. Nitric oxide (NO) exhibits potent antiplatelet activity attributed to its capacity to increase the amount of...

  10. Desmolaris, a novel factor XIa anticoagulant from the salivary gland of the vampire bat (Desmodus rotundus) inhibits inflammation and thrombosis in vivo.

    Science.gov (United States)

    Ma, Dongying; Mizurini, Daniella M; Assumpção, Teresa C F; Li, Yuan; Qi, Yanwei; Kotsyfakis, Michail; Ribeiro, José M C; Monteiro, Robson Q; Francischetti, Ivo M B

    2013-12-12

    The identity of vampire bat saliva anticoagulant remained elusive for almost a century. Sequencing the salivary gland genes from the vampire bat Desmodus rotundus identified Desmolaris as a novel 21.5-kDa naturally deleted (Kunitz 1-domainless) form of tissue factor pathway inhibitor. Recombinant Desmolaris was expressed in HEK293 cells and characterized as a slow, tight, and noncompetitive inhibitor of factor (F) XIa by a mechanism modulated by heparin. Desmolaris also inhibits FXa with lower affinity, independently of protein S. In addition, Desmolaris binds kallikrein and reduces bradykinin generation in plasma activated with kaolin. Truncated and mutated forms of Desmolaris determined that Arg32 in the Kunitz-1 domain is critical for protease inhibition. Moreover, Kunitz-2 and the carboxyl-terminus domains mediate interaction of Desmolaris with heparin and are required for optimal inhibition of FXIa and FXa. Notably, Desmolaris (100 μg/kg) inhibited FeCl3-induced carotid artery thrombus without impairing hemostasis. These results imply that FXIa is the primary in vivo target for Desmolaris at antithrombotic concentrations. Desmolaris also reduces the polyphosphate-induced increase in vascular permeability and collagen- and epinephrine-mediated thromboembolism in mice. Desmolaris emerges as a novel anticoagulant targeting FXIa under conditions in which the coagulation activation, particularly the contact pathway, plays a major pathological role. PMID:24159172

  11. New anticoagulants for the prevention of venous thromboembolism

    Directory of Open Access Journals (Sweden)

    Cecilia Becattini

    2010-04-01

    Full Text Available Cecilia Becattini, Alessandra Lignani, Giancarlo AgnelliInternal and Cardiovascular Medicine and Stroke Unit, University of Perugia, ItalyAbstract: Anticoagulant drugs have an essential role in the prevention and treatment of thromboembolic diseases. Currently available anticoagulants substantially reduce the incidence of thromboembolic events in a number of clinical conditions. However, these agents have limitations that strengthen the case for the development of new anticoagulants. An ideal anticoagulant should be at least as effective as those currently in use, as well as safe, simple to use, and widely applicable. The majority of new anticoagulants currently under investigation are small molecules with a selective and direct anti-Xa or antithrombin action, allowing oral administration in fixed doses. These new agents are in different phases of clinical development. The anti-Xa agent rivaroxaban and the antithrombin agent dabigatran are already available for the prophylaxis of venous thromboembolism in some countries. Apixaban is in an advanced phase of clinical development and several anti-Xa agents are currently approaching phase III clinical trials. Promising results in terms of efficacy and safety profiles have been obtained with these agents in different clinical conditions. Differences in pharmacokinetics and pharmacodynamics could offer the potential for individualized anticoagulant therapies in the near future.Keywords: anticoagulant therapy, antithrombotic therapy, anticoagulants, direct thrombin inhibitors, factor Xa inhibitors

  12. Genetic and environmental factors affecting the coumarin anticoagulant level

    NARCIS (Netherlands)

    L.E. Visser (Loes)

    2004-01-01

    textabstractThis introductory chapter has illustrated that various factors, such as genetic factors, drugs, diet and intercurrent diseases may affect anticoagulation levels. Most of the clinical and pharmacological data related to coumarin anticoagulants have so far been obtained from studying warfa

  13. Clinical considerations of anticoagulation therapy for patients with atrial fibrillation

    Institute of Scientific and Technical Information of China (English)

    Shu ZHANG

    2012-01-01

    Atrial fibrillation (AF) increases the risk of stroke.New anticoagulation agents have recently provided alternative and promising approaches.This paper reviews the current state of anticoagulation therapy in AF patients,focusing on various clinical scenarios and on comparisons,where possible,between western and eastern populations.

  14. Update of the guidelines for lupus anticoagulant detection

    NARCIS (Netherlands)

    Pengo, V.; Tripodi, A.; Reber, G.; Rand, J. H.; Ortel, T. L.; Galli, M.; de Groot, P. G.

    2009-01-01

    One of the conclusions of the subcommittee meeting on Lupus Anticoagulant/Phospholipid dependent antibodies, held in Geneva on 2007, was the need to update the guidelines on Lupus Anticoagulant (LA) detection. Particular emphasis was given to several aspects discussed in this official communication.

  15. Antithrombin inhibits bronchoalveolar activation of coagulation and limits lung injury during Streptococcus pneumoniae pneumonia in rats

    NARCIS (Netherlands)

    Choi, Goda; Hofstra, Jorrit-Jan H; Roelofs, Joris J T H; Rijneveld, Anita W; Bresser, Paul; van der Zee, Jaring S; Florquin, Sandrine; van der Poll, Tom; Levi, Marcel; Schultz, Marcus J

    2008-01-01

    OBJECTIVE: Alveolar fibrin deposition is a hallmark of pneumonia. It has been proposed that natural inhibitors of coagulation, including activated protein C, antithrombin, and tissue factor pathway inhibitor, exert lung-protective effects via anticoagulant and possibly anti-inflammatory pathways. We

  16. Mitogen-activated protein kinase signaling in plants

    DEFF Research Database (Denmark)

    Rodriguez, Maria Cristina Suarez; Petersen, Morten; Mundy, John

    2010-01-01

    of substrate proteins, whose altered activities mediate a wide array of responses, including changes in gene expression. Cascades may share kinase components, but their signaling specificity is maintained by spaciotemporal constraints and dynamic protein-protein interactions and by mechanisms that include......Eukaryotic mitogen-activated protein kinase (MAPK) cascades have evolved to transduce environmental and developmental signals into adaptive and programmed responses. MAPK cascades relay and amplify signals via three types of reversibly phosphorylated kinases leading to the phosphorylation...... crossinhibition, feedback control, and scaffolding. Plant MAPK cascades regulate numerous processes, including stress and hormonal responses, innate immunity, and developmental programs. Genetic analyses have uncovered several predominant MAPK components shared by several of these processes including...

  17. Redox Regulation of the AMP-Activated Protein Kinase

    OpenAIRE

    Yingying Han; Qilong Wang; Ping Song; Yi Zhu; Ming-Hui Zou

    2010-01-01

    Redox state is a critical determinant of cell function, and any major imbalances can cause severe damage or death. Objectives The aim of this study is to determine if AMP-activated protein kinase (AMPK), a cellular energy sensor, is activated by oxidants generated by Berberine in endothelial cells (EC). Methods Bovine aortic endothelial cells (BAEC) were exposed to Berberine. AMPK activity and reactive oxygen species were monitored after the incubation. Results In BAEC, Berberine caused a dos...

  18. Redox Regulation of Protein Tyrosine Phosphatase Activity by Hydroxyl Radical

    OpenAIRE

    Meng, Fan-Guo; Zhang, Zhong-Yin

    2012-01-01

    Substantial evidence suggests that transient production of reactive oxygen species (ROS) such as hydrogen peroxide (H2O2) is an important signaling event triggered by the activation of various cell surface receptors. Major targets of H2O2 include protein tyrosine phosphatases (PTPs). Oxidation of the active site Cys by H2O2 abrogates PTP catalytic activity, thereby potentially furnishing a mechanism to ensure optimal tyrosine phosphorylation in response to a variety of physiological stimuli. ...

  19. Clinical impact of a pharmacist-led inpatient anticoagulation service: a review of the literature

    Directory of Open Access Journals (Sweden)

    Lee T

    2016-05-01

    Full Text Available Tiffany Lee, Erin Davis, Jason Kielly School of Pharmacy, Memorial University, St John's, NL, Canada Background: Anticoagulant therapies provide management options for potentially life-threatening thromboembolic conditions. They also carry significant safety risks, requiring careful consideration of medication dose, close monitoring, and follow-up. Inpatients are particularly at risk, considering the widespread use of anticoagulants in hospitals. This has prompted the introduction of safety goals for anticoagulants in Canada and the USA, which recommend increased pharmacist involvement to reduce patient harm. The goal of this review is to evaluate the efficacy and safety of pharmacist-led inpatient anticoagulation services compared to usual or physician-managed care. Methods: This narrative review includes articles identified through a literature search of PubMed, Embase, and International Pharmaceutical Abstracts databases, as well as hand searches of the references of relevant articles. Full publications of pharmacist-managed inpatient anticoagulation services were eligible if they were published in English and assessed clinical outcomes. Results: Twenty-six studies were included and further divided into two categories: 1 autonomous pharmacist-managed anticoagulation programs (PMAPs and 2 pharmacist recommendation. Pharmacist management of heparin and warfarin appears to result in improvements in some surrogate outcomes (international normalized ratio [INR] stability and time in INR goal range, while results for others are mixed (time to therapeutic INR, length of stay, and activated partial thromboplastin time [aPTT] measures. There is also some indication that PMAPs may be associated with reduced patient mortality. When direct thrombin inhibitors are managed by pharmacists, there seems to be a shorter time to therapeutic aPTT and a greater percentage of time in the therapeutic range, as well as a decrease in the frequency of medication

  20. Biological basis of personalized anticoagulation in cancer: oncogene and oncomir networks as putative regulators of coagulopathy.

    Science.gov (United States)

    D'Asti, Esterina; Rak, Janusz

    2016-04-01

    Activation of stromal response pathways in cancer is increasingly viewed as both a local and systemic extension of molecular alterations driving malignant transformation. Rather than reflecting passive and unspecific responses to anatomical abnormalities, the coagulation system is a target of oncogenic deregulation, impacting the role of clotting and fibrinolytic proteins, and integrating hemostasis, inflammation, angiogenesis and cellular growth effects in cancer. These processes signify, but do not depend on, the clinically manifest coagulopathy and thrombosis. In this regard, the role of driver mutations affecting oncoprotein coding genes such as RAS, EGFR or MET and tumour suppressors (PTEN, TP53) are well described as regulators of tissue factor (TF), protease activated receptors (PAR-1/2) and ectopic coagulation factors (FVII). Indeed, in both adult and pediatric brain tumours the expression patterns of coagulation and angiogenesis regulators (coagulome and angiome, respectively) reflect the molecular subtypes of the underlying diseases (glioblastoma or medulloblastoma) as defined by their oncogenic classifiers and clinical course. This emerging understanding is still poorly established in relation to the transforming effects of non-coding genes, including those responsible for the expression of microRNA (miR). Indeed, several miRs have been recently found to regulate TF and other effectors. We recently documented that in the context of the aggressive embryonal tumour with multilayered rosettes (ETMR) the oncogenic driver miR (miR-520g) suppresses the expression of TF and correlates with hypocoagulant tumour characteristics. Unlike in adult cancers, the growth of pediatric embryonal brain tumour cells as spheres (to maintain stem cell properties) results in upregulation of miR-520g and downregulation of TF expression and activity. We postulate that oncogenic protein and miR coding genes form alternative pathways of coagulation system regulation in different

  1. Polissacarídeos sulfatados isolados das clorofíceas Caulerpa racemosa e Caulerpa cupressoides – extração, fracionamento e atividade anticoagulante =Sulfated polysaccharides isolated from Caulerpa racemosa and Caulerpa cupressoides (Chlorophyceaes – extraction, fractionation and anticoagulant activity

    Directory of Open Access Journals (Sweden)

    José Ariévilo Gurgel Rodrigues

    2010-04-01

    in 0.1 M sodium acetate buffer (pH 5.0 containing 5 mM cysteine and 5 mM EDTA, followed by fractionation on ion exchange DEAE-cellulose column with NaCl gradient. The obtained fractions were analyzed by 0.5% agarose gel electrophoresis and the anticoagulant activity measured by the activated partial thromboplastin time (APTT using normal human plasma, and compared to a standard heparin curve (193 IU mg-1. Similar chromatographic profiles of SP were shown on both species, butwith distinct mobility patterns, when the SP fractions were compared by electrophoresis. SP eluted with 0.75 M of NaCl modified the APTT, whose anticoagulant activities were only 21.23 and 24.36 IU mg-1 for C. racemosa and C. cupressoides, respectively. Therefore, anticoagulant SP isolated from chlorophyceaes showed effects inferior to heparin, and comparative studies of these molecules are also suggested as auxiliary tools in the identification of algae of the same genus.

  2. Novel oral anticoagulants in the management of coronary artery disease.

    Science.gov (United States)

    McMahon, Sean R; Brummel-Ziedins, Kathleen; Schneider, David J

    2016-08-01

    Despite advances in interventional and pharmacologic therapy, survivors of myocardial infarction remain at an increased risk of subsequent cardiovascular events. Initial pharmacological management includes both platelet inhibition and parenteral anticoagulation, whereas long-term pharmacological therapy relies on antiplatelet therapy for prevention of thrombotic complications. Biomarkers showing ongoing thrombin generation after acute coronary syndromes suggest that anticoagulants may provide additional benefit in reducing cardiovascular events. We review the pharmacokinetics of novel anticoagulants, clinical trial results, the role of monitoring, and future directions for the use of novel oral anticoagulants in the treatment of coronary artery disease. Clinical trials have shown that long-term use of oral anticoagulants decreases the risk of cardiovascular events, but they do so at a cost of an increased risk of bleeding. Future studies will need to identify optimal treatment combinations for selected patients and conditions that address both the appropriate combination of therapy and the appropriate dosage of each agent when used in combination. PMID:27228186

  3. Intracranial hemorrhage in cancer patients treated with anticoagulation.

    Science.gov (United States)

    Weinstock, Matthew J; Uhlmann, Erik J; Zwicker, Jeffrey I

    2016-04-01

    Both venous thromboembolism and intracranial metastases are common complications in the setting of primary brain tumors and metastatic malignancies. Anticoagulation is indicated in the presence of cancer-associated thrombosis in order to limit the risk of pulmonary embolism; however, there is reluctance to initiate anticoagulation in the setting of intracranial metastatic disease due to potential for intracranial hemorrhage. Recent evidence suggests that therapeutic anticoagulation can be safely administered in the setting of metastatic brain tumors. This review examines the current understanding of the pathophysiology of intracranial hemorrhage in malignancy, describes the incidence of intracranial hemorrhage in the setting of brain tumors with therapeutic anticoagulation, and outlines management strategies relevant to the treatment of intracranial hemorrhage in the setting of anticoagulation. PMID:27067980

  4. Effects of computer-assisted oral anticoagulant therapy

    DEFF Research Database (Denmark)

    Rasmussen, Rune Skovgaard; Corell, Pernille; Madsen, Poul;

    2012-01-01

    the therapeutic target range compared to traditional oral anticoagulant therapy by physicians. METHODS: 54 patients were randomized equally into 3 groups. Patients in two groups used CoaguChek® systems to measure international normalized ratio (INR) values and had dosages of anticoagulation treatment calculated......UNLABELLED: BACKGROUND: Computer-assistance and self-monitoring lower the cost and may improve the quality of anticoagulation therapy. The main purpose of this clinical investigation was to use computer-assisted oral anticoagulant therapy to improve the time to reach and the time spent within...... in a computer system by an algorithm specific to each group. The third group received traditional anticoagulation treatment by physicians. The obtained INR values were compared regarding the time to reach, and the time spent within, the therapeutic target range, corresponding to INR values from 2 to 3. RESULTS...

  5. Novel oral anticoagulants for thromboprophylaxis after orthopaedic surgery.

    Science.gov (United States)

    Quinlan, Daniel J; Eriksson, Bengt I

    2013-06-01

    The direct thrombin inhibitor, dabigatran, and the selective factor Xa inhibitors, rivaroxaban and apixaban, are new oral anticoagulants that are approved in many countries for prevention of venous thromboembolism in patients undergoing elective hip or knee arthroplasty. All have a rapid onset of action, a low potential for food and drug interactions and a predictable anticoagulant effect that obviates the need for routine coagulation monitoring. These agents offer a convenient alternative to conventional anticoagulant drug regimens, including parenteral low-molecular-weight heparins and fondaparinux, and oral adjusted-dose vitamin K antagonists, for the prevention of venous thromboembolism in this surgical setting. This review summarizes the pharmacology, clinical trial results, bleeding risk and practical use of these new oral anticoagulants in clinical orthopaedic practice. Potential issues to be considered when using these oral anticoagulants include renal impairment, potential drug interactions, neuraxial anaesthesia and management of bleeding. PMID:23953905

  6. [New anticoagulants in the treatment of venous thromboembolism].

    Science.gov (United States)

    Bura-Rivière, Alessandra

    2013-09-01

    Anticoagulant therapy is the cornerstone of treatment of venous thromboembolism (VTE). The treatment needs rapid initial anticoagulaton to minimize the risk of thrombus extension and fata pulmonary embolism, followed by an extended anticoagulation, aimed at preventing recurrent VTE. Till very recently, immediate anticoagulation can only be achieved with parenteral agents, such as heparin, low-molecular-weight heparin, or fondaparinux. Extended treatment usually involves the administration of vitamin K antagonists, such as warfarin. Emerging direct oral anticoagulants have the potential to streamline VTE treatment. These agents include oral anticoagulants that target thrombin or factor Xa. This article reviews the characteristics of these agents, describes the results of clinical trials in venous thromboembolic disease and outlines their strengths and weakness. PMID:24167902

  7. New anticoagulants for the treatment of venous thromboembolism

    Directory of Open Access Journals (Sweden)

    Caio Julio Cesar dos Santos Fernandes

    2016-04-01

    Full Text Available Worldwide, venous thromboembolism (VTE is among the leading causes of death from cardiovascular disease, surpassed only by acute myocardial infarction and stroke. The spectrum of VTE presentations ranges, by degree of severity, from deep vein thrombosis to acute pulmonary thromboembolism. Treatment is based on full anticoagulation of the patients. For many decades, it has been known that anticoagulation directly affects the mortality associated with VTE. Until the beginning of this century, anticoagulant therapy was based on the use of unfractionated or low-molecular-weight heparin and vitamin K antagonists, warfarin in particular. Over the past decades, new classes of anticoagulants have been developed, such as factor Xa inhibitors and direct thrombin inhibitors, which significantly changed the therapeutic arsenal against VTE, due to their efficacy and safety when compared with the conventional treatment. The focus of this review was on evaluating the role of these new anticoagulants in this clinical context.

  8. Stress-induced activation of protein kinase CK2 by direct interaction with p38 mitogen-activated protein kinase

    DEFF Research Database (Denmark)

    Sayed, M; Kim, S O; Salh, B S;

    2000-01-01

    Protein kinase CK2 has been implicated in the regulation of a wide range of proteins that are important in cell proliferation and differentiation. Here we demonstrate that the stress signaling agents anisomycin, arsenite, and tumor necrosis factor-alpha stimulate the specific enzyme activity of CK2...... to be an allosteric mechanism. Furthermore, we demonstrate that anisomycin- and tumor necrosis factor-alpha-induced phosphorylation of p53 at Ser-392, which is important for the transcriptional activity of this growth suppressor protein, requires p38 MAP kinase and CK2 activities....... in the human cervical carcinoma HeLa cells by up to 8-fold, and this could be blocked by the p38 MAP kinase inhibitor SB203580. We show that p38alpha MAP kinase, in a phosphorylation-dependent manner, can directly interact with the alpha and beta subunits of CK2 to activate the holoenzyme through what appears...

  9. Cardioversion in Acute Atrial Fibrillation without Anticoagulation

    Directory of Open Access Journals (Sweden)

    KE Juhani Airaksinen, MD, PhD; Wail Nammas, MD, PhD; Ilpo Nuotio, MD, PhD

    2013-12-01

    Full Text Available The main alternative therapeutic strategies for acute atrial fibrillation are rate versus rhythm control. A major concern in cardioversion of newly detected atrial fibrillation is the risk of thromboembolic events. The vast majority of these events occur in the first week following cardioversion. Transesophageal echocardiography has demonstrated that thrombus and dense spontaneous echo contrast may occur in the left atrium and left atrial appendage also in patients with acute atrial fibrillation (<48 hours scheduled for cardioversion. Moreover, atrial function may become impaired immediately following successful cardioversion. Thus, the current North American and European guidelines recommend that patients with acute atrial fibrillation should undergo cardioversion under cover of unfractionated or low-molecular weight heparin followed by oral anticoagulation for at least 4 weeks in patients in patients at moderate-to-high risk for stroke. In line with the guidelines, new evidence from a large patient population suggests that after successful cardioversion of acute atrial fibrillation, patients have a low overall risk of thromboembolic events without any anticoagulation when they have no risk factors for thromboembolism. In contrast, the risk is in the range of 10% in patients with multiple classic risk factors for thromboembolism.

  10. Anticoagulation in adults with congenital heart disease

    DEFF Research Database (Denmark)

    Jensen, A S; Idorn, L; Nørager, B;

    2015-01-01

    Adults with congenital heart disease are a growing population. One of the major challenges in the care of these patients is to prevent thromboembolic episodes. Despite relative young age and no typical cardiovascular risk factors, this cohort has a high prevalence of thrombotic events. It is diff......Adults with congenital heart disease are a growing population. One of the major challenges in the care of these patients is to prevent thromboembolic episodes. Despite relative young age and no typical cardiovascular risk factors, this cohort has a high prevalence of thrombotic events....... It is difficult to use treatment algorithms from the general adult population with acquired heart disease in this heterogeneous population due to special conditions such as myocardial scarring after previous surgery, atypical atrial flutter, prothrombotic conditions and the presence of interatrial shunts....... Furthermore, there is a lack of scientific evidence regarding how to prevent thromboembolic events with anticoagulation in adults with congenital heart disease. The aim of this paper is to review the current literature pertaining to anticoagulation in adults with congenital heart disease and hence enable...

  11. Hydrodynamic collective effects of active proteins in biological membranes

    Science.gov (United States)

    Koyano, Yuki; Kitahata, Hiroyuki; Mikhailov, Alexander S.

    2016-08-01

    Lipid bilayers forming biological membranes are known to behave as viscous two-dimensional fluids on submicrometer scales; usually they contain a large number of active protein inclusions. Recently, it was shown [A. S. Mikhailov and R. Kapral, Proc. Natl. Acad. Sci. USA 112, E3639 (2015), 10.1073/pnas.1506825112] that such active proteins should induce nonthermal fluctuating lipid flows leading to diffusion enhancement and chemotaxislike drift for passive inclusions in biomembranes. Here, a detailed analytical and numerical investigation of such effects is performed. The attention is focused on the situations when proteins are concentrated within lipid rafts. We demonstrate that passive particles tend to become attracted by active rafts and are accumulated inside them.

  12. Cyclic AMP activates the mitogen-activated protein kinase cascade in PC12 cells

    DEFF Research Database (Denmark)

    Frödin, M; Peraldi, P; Van Obberghen, E

    1994-01-01

    Mitogen-activated protein (MAP) kinases are activated in response to a large variety of extracellular signals, including growth factors, hormones, and neurotransmitters, which activate distinct intracellular signaling pathways. Their activation by the cAMP-dependent pathway, however, has not been...

  13. Anti-tumor activities andapoptotic mechanism ofribosome-inactivating proteins

    Institute of Scientific and Technical Information of China (English)

    MeiqiZeng; ManyinZheng; DeshengLu; JunWang; WenqiJiang; OuSha

    2015-01-01

    Ribosome-inactivating proteins (RIPs) belong to a family of enzymes that attack eukaryotic ribosomes and potently inhibit cellular protein synthesis. RIPs possess several biomedical properties, including anti-viral and anti-tumor activi-ties. Multiple RIPs are known to inhibit tumor cell proliferation through inducing apoptosis in a variety of cancers, such as breast cancer, leukemia/lymphoma, and hepatoma. This review focuses on the anti-tumor activities of RIPs and their apoptotic effects through three closely related pathways: mitochondrial, death receptor, and endoplasmic reticulum pathways.

  14. A nitric oxide-releasing heparin conjugate for delivery of a combined antiplatelet/anticoagulant agent.

    Science.gov (United States)

    Suchyta, Dakota J; Handa, Hitesh; Meyerhoff, Mark E

    2014-02-01

    Heparin is a widely used anticoagulant due to its ability to inhibit key components in the coagulation cascade such as Factor Xa and thrombin (Factor IIa). Its potential to preferentially bind to antithrombin (ATIII) results in a conformational change and activation that leads to the prevention of fibrin formation from fibrinogen and ultimately obstructs a hemostatic plug from forming. Nitric oxide (NO) exhibits potent antiplatelet activity attributed to its capacity to increase the amount of cyclic guanosine monophosphate (cGMP) within platelets, which decreases the Ca(2+) concentration required for platelet activation. Currently there is no single agent that combines the functions of both antiplatelet and anticoagulant (anti-Xa and anti-IIa) activities to effectively block both the extrinsic and the intrinsic coagulation pathways. The research reported herein demonstrates the ability to combine the physiological capabilities of both heparin and NO into one functional compound via use of a spermine derivative of heparin, thus enabling formation of a novel diazeniumdiolate (NONOate). The heparin-spermine NONOate has a half-life of 85 min at 25 °C (pH 7.4). The heparin backbone of the conjugate maintains its anticoagulant activity as demonstrated via an anti-Xa assay, providing an anticoagulant conversion of 3.6 μg/mL of the heparin-spermine-NONO conjugate being equivalent to 2.5 μg/mL (0.50 IU/mL) of underivatized heparin in terms of anti-Xa activity. Using standard platelet aggregometry, it is shown that the functionality of the NO release portion of the heparin conjugate prevents (nearly 100%) platelet aggregation in the presence of adenosine diphosphate (ADP, platelet agonist). PMID:24423090

  15. Exactin: A specific inhibitor of Factor X activation by extrinsic tenase complex from the venom of Hemachatus haemachatus.

    Science.gov (United States)

    Girish, Vallerinteavide Mavelli; Kini, R Manjunatha

    2016-01-01

    Unwanted clots lead to heart attack and stroke that result in a large number of deaths. Currently available anticoagulants have some drawbacks including their non-specific actions. Therefore novel anticoagulants that target specific steps in the coagulation pathway are being sought. Here we describe the identification and characterization of a novel anticoagulant protein from the venom of Hemachatus haemachatus (African Ringhals cobra) that specifically inhibits factor X (FX) activation by the extrinsic tenase complex (ETC) and thus named as exactin. Exactin belongs to the three-finger toxin (3FTx) family, with high sequence identity to neurotoxins and low identity to the well-characterized 3FTx anticoagulants-hemextin and naniproin. It is a mixed-type inhibitor of ETC with the kinetic constants, Ki' and Ki determined as 30.62 ± 7.73 nM and 153.75 ± 17.96 nM, respectively. Exactin does not bind to the active site of factor VIIa and factor Xa based on its weak inhibition (IC50 ≫ 300 μM) to the amidolytic activities of these proteases. Exactin shows exquisite macromolecular specificity to FX activation as compared to factor IX activation by ETC. Exactin thus displays a distinct mechanism when compared to other anticoagulants targeting ETC, with its selective preference to ETC-FX [ES] complex. PMID:27558950

  16. Exactin: A specific inhibitor of Factor X activation by extrinsic tenase complex from the venom of Hemachatus haemachatus

    Science.gov (United States)

    Girish, Vallerinteavide Mavelli; Kini, R. Manjunatha

    2016-01-01

    Unwanted clots lead to heart attack and stroke that result in a large number of deaths. Currently available anticoagulants have some drawbacks including their non-specific actions. Therefore novel anticoagulants that target specific steps in the coagulation pathway are being sought. Here we describe the identification and characterization of a novel anticoagulant protein from the venom of Hemachatus haemachatus (African Ringhals cobra) that specifically inhibits factor X (FX) activation by the extrinsic tenase complex (ETC) and thus named as exactin. Exactin belongs to the three-finger toxin (3FTx) family, with high sequence identity to neurotoxins and low identity to the well-characterized 3FTx anticoagulants-hemextin and naniproin. It is a mixed-type inhibitor of ETC with the kinetic constants, Ki’ and Ki determined as 30.62 ± 7.73 nM and 153.75 ± 17.96 nM, respectively. Exactin does not bind to the active site of factor VIIa and factor Xa based on its weak inhibition (IC50 ≫ 300 μM) to the amidolytic activities of these proteases. Exactin shows exquisite macromolecular specificity to FX activation as compared to factor IX activation by ETC. Exactin thus displays a distinct mechanism when compared to other anticoagulants targeting ETC, with its selective preference to ETC-FX [ES] complex. PMID:27558950

  17. Exposure pathways of anticoagulant rodenticides to nontarget wildlife.

    Science.gov (United States)

    Elliott, John E; Hindmarch, Sofi; Albert, Courtney A; Emery, Jason; Mineau, Pierre; Maisonneuve, France

    2014-02-01

    Second-generation anticoagulant rodenticides are widely reported to contaminate and poison nontarget wildlife, primarily predatory birds and mammals. Exposure pathways, however, have not been well defined. Here, we examined potential movement of rodenticides from deployment of bait to exposure of small mammals and other biota. At two adjacent working farms, we placed baits containing either brodifacoum or bromadiolone. We monitored movement of those compounds to the surrounding environment by collecting small mammals, birds, and invertebrates. Similar collections were made at a third agricultural setting without active bait deployment, but located among intensive livestock production and regular rodenticide use by farmers. Livers and whole invertebrate samples were analyzed for rodenticides using a sensitive LC-MSMS method. Norway rats (Rattus norvegicus) from both baited and non-baited farms had residues of brodifacoum or bromadiolone, implicating rats as an important exposure pathway to wildlife. Among 35 analyzed nontarget small mammals, a single vole had high hepatic residues (18.6 μ/g), providing some indication of a small mammal pathway. One song sparrow (Melospiza melodia) sample from a baited farm contained 0.073 μg/g of brodifacoum in liver, while 0.39 μg/g of diphacinone was measured in a pool of carrion beetles (Dermestes spp.) from the non-baited farm area, implicating avian and invertebrate components in exposure pathways. Regurgitated pellets of barn owl (Tyto alba) selected randomly from baited farms contained no detectable rodenticide residues, while 90% of owl pellets collected from a variety of farms, and selected for the presence of rat fur, contained detectable anticoagulant residues. We recorded behavior of a captive sample of a representative songbird, the house sparrow (Passer domesticus); they readily entered bait stations and fed on (unloaded) bait. PMID:24048882

  18. Systemic anticoagulation related to heparin locking of non-tunnelled venous dialysis catheters in intensive care patients.

    Science.gov (United States)

    Bong, Y C; Walsham, J

    2016-07-01

    Heparin locking of venous dialysis catheters is routinely performed in intensive care to maintain catheter patency when the catheters are not being used. Leakage of heparin into the circulation can potentially cause systemic anticoagulation and may present a risk to intensive care patients. To assess the effect of 5000 units per millilitre heparin locking of non-tunnelled dialysis catheters on systemic anticoagulation, we performed a prospective observational study of ten intensive care patients receiving heparin locking of dialysis catheters in an adult tertiary intensive care unit between July and September 2015. Activated partial thromboplastin time (APTT) was measured prior to, and three minutes after, heparin locking of catheter lumens with the manufacturer's recommended locking volume to assess the effect on systemic anticoagulation. Heparin locking of venous dialysis catheters resulted in a significant rise in APTT (P=0.002). The median rise was by 56 seconds (interquartile range 30-166.5). Following heparin locking, 80% of patients had APTT values within or above the range associated with therapeutic anticoagulation. Heparin locking of non-tunnelled venous dialysis catheters can cause systemic anticoagulation in intensive care patients and therefore poses a potential risk to patient safety.

  19. Systemic anticoagulation related to heparin locking of non-tunnelled venous dialysis catheters in intensive care patients.

    Science.gov (United States)

    Bong, Y C; Walsham, J

    2016-07-01

    Heparin locking of venous dialysis catheters is routinely performed in intensive care to maintain catheter patency when the catheters are not being used. Leakage of heparin into the circulation can potentially cause systemic anticoagulation and may present a risk to intensive care patients. To assess the effect of 5000 units per millilitre heparin locking of non-tunnelled dialysis catheters on systemic anticoagulation, we performed a prospective observational study of ten intensive care patients receiving heparin locking of dialysis catheters in an adult tertiary intensive care unit between July and September 2015. Activated partial thromboplastin time (APTT) was measured prior to, and three minutes after, heparin locking of catheter lumens with the manufacturer's recommended locking volume to assess the effect on systemic anticoagulation. Heparin locking of venous dialysis catheters resulted in a significant rise in APTT (P=0.002). The median rise was by 56 seconds (interquartile range 30-166.5). Following heparin locking, 80% of patients had APTT values within or above the range associated with therapeutic anticoagulation. Heparin locking of non-tunnelled venous dialysis catheters can cause systemic anticoagulation in intensive care patients and therefore poses a potential risk to patient safety. PMID:27456177

  20. Perioperative management of anticoagulant users scheduled for glaucoma surgery: a survey among the Brazilian Glaucoma Society members

    Directory of Open Access Journals (Sweden)

    Marcos Balbino

    2013-12-01

    Full Text Available PURPOSE: To investigate and describe, among the members of the Brazilian Glaucoma Society (BGS, the practices regarding the perioperative management of anticoagulants (warfarin and aspirin use in patients scheduled for glaucoma surgery. METHODS: The active members of the Brazilian Glaucoma Society answered a questionnaire evaluating different aspects of their current perioperative management of glaucomatous patients taking warfarin or aspirin. RESULTS: A total of 52 participants returned a complete questionnaire. Warfarin or aspirin was routinely interrupted prior to glaucoma surgery by 82.7% of the respondents. The majority of the surgeons who discontinued these medications reported doing so 7 days prior to surgery and resumed their use the day after the procedure. Almost half of our interviewees reported hemorrhagic complications that could be related to anticoagulant therapy. A large number of the surgeons (86.5% preferred a particular surgical technique for anticoagulated patients; however, most of them (88.5% do not change the anesthetic planning in such patients. Finally, the majority of the participants (90.4% refer their anticoagulated patients to a preoperative appointment with a cardiologist or a general practitioner before the surgery. CONCLUSIONS: The majority of Brazilian Glaucoma Society members participating in this study interrupt either warfarin or aspirin prior to glaucoma surgery. Although there is scant information available in the literature to offer definitive guidance, most participants from the Brazilian Glaucoma Society seem to share the same opinion when it comes to perioperative management of anticoagulant users.

  1. Analysis of protein phosphorylation in nerve terminal reveals extensive changes in active zone proteins upon exocytosis.

    Science.gov (United States)

    Kohansal-Nodehi, Mahdokht; Chua, John Je; Urlaub, Henning; Jahn, Reinhard; Czernik, Dominika

    2016-01-01

    Neurotransmitter release is mediated by the fast, calcium-triggered fusion of synaptic vesicles with the presynaptic plasma membrane, followed by endocytosis and recycling of the membrane of synaptic vesicles. While many of the proteins governing these processes are known, their regulation is only beginning to be understood. Here we have applied quantitative phosphoproteomics to identify changes in phosphorylation status of presynaptic proteins in resting and stimulated nerve terminals isolated from the brains of Wistar rats. Using rigorous quantification, we identified 252 phosphosites that are either up- or downregulated upon triggering calcium-dependent exocytosis. Particularly pronounced were regulated changes of phosphosites within protein constituents of the presynaptic active zone, including bassoon, piccolo, and RIM1. Additionally, we have mapped kinases and phosphatases that are activated upon stimulation. Overall, our study provides a snapshot of phosphorylation changes associated with presynaptic activity and provides a foundation for further functional analysis of key phosphosites involved in presynaptic plasticity. PMID:27115346

  2. Structure versus anticoagulant and antithrombotic actions of marine sulfated polysaccharides

    Directory of Open Access Journals (Sweden)

    Vitor Hugo Pomin

    2012-08-01

    Full Text Available Marine sulfated polysaccharides (MSP, such as sulfated fucans (SF, sulfated galactans (SG and glycosaminoglycans (GAG isolated from either algae or invertebrate animals, are highly anionic polysaccharides capable of interacting with certain cationic proteins, such as (co-factors of the coagulation cascade during clotting-inhibition processes. These molecular complexes between MSP and coagulation-related proteins might, at first glance, be assumed to be driven mostly by electrostatic interactions. However, a systematic comparison using several novel sulfated polysaccharides composed of repetitive oligosaccharides with clear sulfation patterns has shown that these molecular interactions are regulated essentially by the stereochemistry of the glycans (which depends on a conjunction of anomericity, monosaccharide, conformational preference, and glycosylation and sulfation sites, rather than just a simple consequence of their negative charge density (mainly the number of sulfate groups. Here, we present an overview of the structure-function relationships of MSP, correlating their structures with their potential anticoagulant and antithrombotic actions, since pathologies related to the cardiovascular system are one of the major causes of illness and mortality in the world.

  3. Detergent activation of the binding protein in the folate radioassay

    International Nuclear Information System (INIS)

    A minor cow's whey protein associated with β-lactoglobulin is used as binding protein in the competitive radioassay for serum and erythrocyte folate. Seeking to optimize the assay, we tested the performance of binder solutions of increasing purity. The folate binding protein was isolated from cow's whey by means of CM-Sepharose CL-6B cation-exchange chromatography, and further purified on a methotrexate-AH-Sepharose 4B affinity matrix. In contrast to β-lactoglobulin, the purified protein did not bind folate unless the detergents cetyltrimethylammonium (10 mmol/Ll) or Triton X-100 (1 g/L) were present. Such detergent activation was not needed in the presence of serum. There seems to be a striking analogy between these phenomena and the well-known reactivation of certain purified membrane-derived enzymes by surfactants

  4. Controlling Protein Activity and Degradation Using Blue Light.

    Science.gov (United States)

    Lutz, Anne P; Renicke, Christian; Taxis, Christof

    2016-01-01

    Regulation of protein stability is a fundamental process in eukaryotic cells and pivotal to, e.g., cell cycle progression, faithful chromosome segregation, or protein quality control. Synthetic regulation of protein stability requires conditional degradation sequences (degrons) that induce a stability switch upon a specific signal. Fusion to a selected target protein permits to influence virtually every process in a cell. Light as signal is advantageous due to its precise applicability in time, space, quality, and quantity. Light control of protein stability was achieved by fusing the LOV2 photoreceptor domain of Arabidopsis thaliana phototropin1 with a synthetic degron (cODC1) derived from the carboxy-terminal degron of ornithine decarboxylase to obtain the photosensitive degron (psd) module. The psd module can be attached to the carboxy terminus of target proteins that are localized to the cytosol or nucleus to obtain light control over their stability. Blue light induces structural changes in the LOV2 domain, which in turn lead to activation of the degron and thus proteasomal degradation of the whole fusion protein. Variants of the psd module with diverse characteristics are useful to fine-tune the stability of a selected target at permissive (darkness) and restrictive conditions (blue light). PMID:26965116

  5. Evaluation of the Effect of Lime Fruit Juice on the Anticoagulant Effect of Warfarin

    Science.gov (United States)

    Adepoju, GKA; Adeyemi, T

    2010-01-01

    Aim: Citrus aurantifolia (Family Rutaceae) is commonly known as a familiar food and medicine, and s therapeutic effectiveness in a variety of diseases has been suggested in traditional medicine. Various complementary and alternative medicines (CAM) have been shown to interact with orthodox medicines. Hence, the aim of this study is to investigate such a phenomenon particularly the interaction of lime fruit juice with warfarin. Materials and Method: Wistar strain albino rats of both sexes weighing between 190 and 230g were administered with oral doses of the respective drugs used depending on the groups of animals. Effects on the anticoagulant activity of warfarin were determined by standard laboratory methods. Result: Lime fruit juice caused a reduction in the anticoagulant activity of warfarin. Conclusion: This finding has shown that CAM can interact with orthodox medicines hence, warfarin prescribers need to be aware of the usage of CAM and monitor the international normalized ratio (INR) of their patients more frequently. PMID:21042484

  6. Management of antiplatelet and anticoagulant therapy for endoscopic procedures: introduction to novel oral anticoagulants

    Directory of Open Access Journals (Sweden)

    Martha L. González-Bárcenas

    2016-02-01

    Full Text Available The development of novel antithrombotic therapy in the past few years and its prescription in patients with cardiovascular and circulatory disease has widened the spectrum of drugs that need to be considered when performing an endoscopic procedure. The balance between the thrombotic risk patients carry due to their medical history and the bleeding risk involved in endoscopic procedures should be thoroughly analyzed by Gastroenterologists. New oral anticoagulants (NOACs impose an additional task. These agents, that specifically target factor IIa or Xa, do not dispose of an anticoagulation monitoring method nor have an antidote to revert their effect, just as with antiplatelet agents. Understanding the fundamental aspects of these drugs provides the necessary knowledge to determine the ideal period the antithrombotic therapy should be interrupted in order to perform the endoscopic procedure, offering maximum safety for patients and optimal results.

  7. Installing hydrolytic activity into a completely de novo protein framework

    Science.gov (United States)

    Burton, Antony J.; Thomson, Andrew R.; Dawson, William M.; Brady, R. Leo; Woolfson, Derek N.

    2016-09-01

    The design of enzyme-like catalysts tests our understanding of sequence-to-structure/function relationships in proteins. Here we install hydrolytic activity predictably into a completely de novo and thermostable α-helical barrel, which comprises seven helices arranged around an accessible channel. We show that the lumen of the barrel accepts 21 mutations to functional polar residues. The resulting variant, which has cysteine-histidine-glutamic acid triads on each helix, hydrolyses p-nitrophenyl acetate with catalytic efficiencies that match the most-efficient redesigned hydrolases based on natural protein scaffolds. This is the first report of a functional catalytic triad engineered into a de novo protein framework. The flexibility of our system also allows the facile incorporation of unnatural side chains to improve activity and probe the catalytic mechanism. Such a predictable and robust construction of truly de novo biocatalysts holds promise for applications in chemical and biochemical synthesis.

  8. Antioxidant and Anticoagulant Status Were Improved by Personalized Dietary Intervention Based on Biochemical and Clinical Parameters in Cancer Patients.

    Science.gov (United States)

    Lee, Ga-Yi; Lee, Jong Jyun; Lee, Seung-Min

    2015-01-01

    We investigated whether personalized dietary intervention could improve clinical measurements such as immune cell-mediated cytotoxicity, serum albumin, derivatives of reactive oxygen metabolites (D-ROMS), D-dimer, and fibrinogen. Cancer patients received either a treatment support diet (TD, for those with chemotherapy), or a remission support diet (RD; for those in remission) for at least 3 wk (21-61 days). Both diets were low glycemic, low fat, and high plant protein diets; the diet for the TD group contained an additional 0.5 servings of protein. Based on clinical values, additional amounts of garlic, onion, tomato, shiitake, rice bran, kale, blueberry, pineapples, and/or turmeric powder were provided in regular meals. Estimated daily intake of protein, plant fat, garlic, onion, allicin, and quercetin was greater in the TD compared to the RD. An increased intake of vitamin A, vitamin C, vitamin E and selenium and a reduction in D-dimer were noted compared to baseline diets in both groups. A decrease in D-ROMS in the RD and an increase in albumin and an increased tendency in cytotoxicity in the TD were observed. In conclusion, personalized diets with supplemented functional ingredients improved antioxidant status and/or anticoagulant activity in cancer patients undergoing chemotherapy and in remission. PMID:26333154

  9. Efficacy and safety of new oral anticoagulants in prophylaxis and treatment of venous thromboembolism

    OpenAIRE

    Luca Masotti; Cecilia Becattini; Roberto Cappelli; Giancarlo Landini; Alessandro Pampana; Domenico Prisco; Giancarlo Agnelli

    2011-01-01

    One of the main innovation emerged in recent years in the field of venous thromboembolism (VTE) has been represented by the clinical development and marketing of new oral anticoagulant agents used for prophylaxis and acute treatment. These drugs are represented by direct thrombin inhibitors (anti-factor IIa) and the direct inhibitors of activated factor X (anti-Xa). The main achievement of these new agents is represented by their ease of use without laboratory monitoring or dose adjustment. D...

  10. Thromboembolism and anticoagulation after Fontan surgery.

    Science.gov (United States)

    Viswanathan, Sangeetha

    2016-01-01

    This review attempts to answer the common questions faced by a clinician regarding thromboembolism and thromboprophylaxis in patients following Fontan surgery. The review is in an easy to understand question and answer format and discusses the currently available literature on the subject in an attempt to arrive at practical clinically relevant solutions. Patients who have undergone the Fontan operation are at a high risk for thromboembolism. Based on available evidence, there is a strong rationale for thromboprophylaxis. However, it is not clear as to which agent should be administered to prevent thromboembolic events. While the available evidence suggests that antiplatelet agents alone may be as good as oral anticoagulants, there is a need for a large multicenter randomized control trial comparing these two common strategies to deliver a clear verdict.

  11. Thromboembolism and anticoagulation after Fontan surgery.

    Science.gov (United States)

    Viswanathan, Sangeetha

    2016-01-01

    This review attempts to answer the common questions faced by a clinician regarding thromboembolism and thromboprophylaxis in patients following Fontan surgery. The review is in an easy to understand question and answer format and discusses the currently available literature on the subject in an attempt to arrive at practical clinically relevant solutions. Patients who have undergone the Fontan operation are at a high risk for thromboembolism. Based on available evidence, there is a strong rationale for thromboprophylaxis. However, it is not clear as to which agent should be administered to prevent thromboembolic events. While the available evidence suggests that antiplatelet agents alone may be as good as oral anticoagulants, there is a need for a large multicenter randomized control trial comparing these two common strategies to deliver a clear verdict. PMID:27625521

  12. Reassessing the Potential Activities of Plant CGI-58 Protein.

    Science.gov (United States)

    Khatib, Abdallah; Arhab, Yani; Bentebibel, Assia; Abousalham, Abdelkarim; Noiriel, Alexandre

    2016-01-01

    Comparative Gene Identification-58 (CGI-58) is a widespread protein found in animals and plants. This protein has been shown to participate in lipolysis in mice and humans by activating Adipose triglyceride lipase (ATGL), the initial enzyme responsible for the triacylglycerol (TAG) catabolism cascade. Human mutation of CGI-58 is the cause of Chanarin-Dorfman syndrome, an orphan disease characterized by a systemic accumulation of TAG which engenders tissue disorders. The CGI-58 protein has also been shown to participate in neutral lipid metabolism in plants and, in this case, a mutation again provokes TAG accumulation. Although its roles as an ATGL coactivator and in lipid metabolism are quite clear, the catalytic activity of CGI-58 is still in question. The acyltransferase activities of CGI-58 have been speculated about, reported or even dismissed and experimental evidence that CGI-58 expressed in E. coli possesses an unambiguous catalytic activity is still lacking. To address this problem, we developed a new set of plasmids and site-directed mutants to elucidate the in vivo effects of CGI-58 expression on lipid metabolism in E. coli. By analyzing the lipid composition in selected E. coli strains expressing CGI-58 proteins, and by reinvestigating enzymatic tests with adequate controls, we show here that recombinant plant CGI-58 has none of the proposed activities previously described. Recombinant plant and mouse CGI-58 both lack acyltransferase activity towards either lysophosphatidylglycerol or lysophosphatidic acid to form phosphatidylglycerol or phosphatidic acid and recombinant plant CGI-58 does not catalyze TAG or phospholipid hydrolysis. However, expression of recombinant plant CGI-58, but not mouse CGI-58, led to a decrease in phosphatidylglycerol in all strains of E. coli tested, and a mutation of the putative catalytic residues restored a wild-type phenotype. The potential activities of plant CGI-58 are subsequently discussed. PMID:26745266

  13. Reassessing the Potential Activities of Plant CGI-58 Protein.

    Directory of Open Access Journals (Sweden)

    Abdallah Khatib

    Full Text Available Comparative Gene Identification-58 (CGI-58 is a widespread protein found in animals and plants. This protein has been shown to participate in lipolysis in mice and humans by activating Adipose triglyceride lipase (ATGL, the initial enzyme responsible for the triacylglycerol (TAG catabolism cascade. Human mutation of CGI-58 is the cause of Chanarin-Dorfman syndrome, an orphan disease characterized by a systemic accumulation of TAG which engenders tissue disorders. The CGI-58 protein has also been shown to participate in neutral lipid metabolism in plants and, in this case, a mutation again provokes TAG accumulation. Although its roles as an ATGL coactivator and in lipid metabolism are quite clear, the catalytic activity of CGI-58 is still in question. The acyltransferase activities of CGI-58 have been speculated about, reported or even dismissed and experimental evidence that CGI-58 expressed in E. coli possesses an unambiguous catalytic activity is still lacking. To address this problem, we developed a new set of plasmids and site-directed mutants to elucidate the in vivo effects of CGI-58 expression on lipid metabolism in E. coli. By analyzing the lipid composition in selected E. coli strains expressing CGI-58 proteins, and by reinvestigating enzymatic tests with adequate controls, we show here that recombinant plant CGI-58 has none of the proposed activities previously described. Recombinant plant and mouse CGI-58 both lack acyltransferase activity towards either lysophosphatidylglycerol or lysophosphatidic acid to form phosphatidylglycerol or phosphatidic acid and recombinant plant CGI-58 does not catalyze TAG or phospholipid hydrolysis. However, expression of recombinant plant CGI-58, but not mouse CGI-58, led to a decrease in phosphatidylglycerol in all strains of E. coli tested, and a mutation of the putative catalytic residues restored a wild-type phenotype. The potential activities of plant CGI-58 are subsequently discussed.

  14. Reassessing the Potential Activities of Plant CGI-58 Protein.

    Science.gov (United States)

    Khatib, Abdallah; Arhab, Yani; Bentebibel, Assia; Abousalham, Abdelkarim; Noiriel, Alexandre

    2016-01-01

    Comparative Gene Identification-58 (CGI-58) is a widespread protein found in animals and plants. This protein has been shown to participate in lipolysis in mice and humans by activating Adipose triglyceride lipase (ATGL), the initial enzyme responsible for the triacylglycerol (TAG) catabolism cascade. Human mutation of CGI-58 is the cause of Chanarin-Dorfman syndrome, an orphan disease characterized by a systemic accumulation of TAG which engenders tissue disorders. The CGI-58 protein has also been shown to participate in neutral lipid metabolism in plants and, in this case, a mutation again provokes TAG accumulation. Although its roles as an ATGL coactivator and in lipid metabolism are quite clear, the catalytic activity of CGI-58 is still in question. The acyltransferase activities of CGI-58 have been speculated about, reported or even dismissed and experimental evidence that CGI-58 expressed in E. coli possesses an unambiguous catalytic activity is still lacking. To address this problem, we developed a new set of plasmids and site-directed mutants to elucidate the in vivo effects of CGI-58 expression on lipid metabolism in E. coli. By analyzing the lipid composition in selected E. coli strains expressing CGI-58 proteins, and by reinvestigating enzymatic tests with adequate controls, we show here that recombinant plant CGI-58 has none of the proposed activities previously described. Recombinant plant and mouse CGI-58 both lack acyltransferase activity towards either lysophosphatidylglycerol or lysophosphatidic acid to form phosphatidylglycerol or phosphatidic acid and recombinant plant CGI-58 does not catalyze TAG or phospholipid hydrolysis. However, expression of recombinant plant CGI-58, but not mouse CGI-58, led to a decrease in phosphatidylglycerol in all strains of E. coli tested, and a mutation of the putative catalytic residues restored a wild-type phenotype. The potential activities of plant CGI-58 are subsequently discussed.

  15. In vitro antithrombotic activities of peanut protein hydrolysates.

    Science.gov (United States)

    Zhang, Shao Bing

    2016-07-01

    The antithrombotic activities of peanut protein hydrolysates were investigated using a microplates assay. When peanut proteins were hydrolyzed to a limited extent by various enzymes, their thrombin inhibitory abilities were significantly enhanced. However, the resultant hydrolysates showed significantly different activities even at the same degrees of hydrolysis. The hydrolysates generated by Alcalase 2.4L displayed the best antithrombotic activities and the hydrolysis process was further optimized by response surface methodology. The antithrombotic activities were increased to 86% based on a protein concentration of 50mg/ml under the optimal conditions: pH 8.5, enzyme concentration of 5000IU/g of peanut proteins, and 2h hydrolysis time at 50°C. The Alcalase 2.4L crude hydrolysates were then fractionated successively by preparative and semi-preparative reverse-phase high-performance liquid chromatography (RP-HPLC). The peptide fraction collected inhibited thrombin-catalyzed coagulation of fibrinogen completely at a concentration of 0.4mg/ml, with an antithrombotic activity close to that of heparin at quite a low concentration (0.2mg/ml). This peptide fraction was further analyzed by online reverse-phase ultra-performance liquid chromatography (RP-UPLC) coupled to matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS), and three new peptides were identified as Ser-Trp-Ala-Gln-Leu, Gly-Asn-His-Glu-Ala-Gly-Glu and Cys-Phe-Asn-Glu-Tyr-Glu, respectively. This research provided an effective way to produce antithrombotic peptides from peanut proteins, and also helped to elucidate the structure-function relationships of peanut peptides. PMID:26920259

  16. Auxin efflux by PIN-FORMED proteins is activated by two different protein kinases, D6 PROTEIN KINASE and PINOID

    KAUST Repository

    Zourelidou, Melina

    2014-06-19

    The development and morphology of vascular plants is critically determined by synthesis and proper distribution of the phytohormone auxin. The directed cell-to-cell distribution of auxin is achieved through a system of auxin influx and efflux transporters. PIN-FORMED (PIN) proteins are proposed auxin efflux transporters, and auxin fluxes can seemingly be predicted based on the-in many cells-asymmetric plasma membrane distribution of PINs. Here, we show in a heterologous Xenopus oocyte system as well as in Arabidopsis thaliana inflorescence stems that PIN-mediated auxin transport is directly activated by D6 PROTEIN KINASE (D6PK) and PINOID (PID)/WAG kinases of the Arabidopsis AGCVIII kinase family. At the same time, we reveal that D6PKs and PID have differential phosphosite preferences. Our study suggests that PIN activation by protein kinases is a crucial component of auxin transport control that must be taken into account to understand auxin distribution within the plant.

  17. Emergency management of patients being treated with oral anticoagulants

    Directory of Open Access Journals (Sweden)

    Franco Manzato

    2013-12-01

    Full Text Available Vitamin K antagonists (VKA are among the most widely prescribed drugs in the industrialized world. In fact, for decades, VKA have been the only orally available anticoagulant for the primary and secondary prevention of venous and arterial thrombotic events. Their efficacy has been widely demonstrated in a series of studies carried out in the 1990s. Since the incidences of atrial fibrillation and venous thromboembolism increase exponentially with age, the number of anticoagulated patients is destined to increase. This paper examines anticoagulation therapy management with particular attention to the use of VKA.

  18. Periablative Anticoagulation Strategies in Patients with Atrial Fibrillation

    Directory of Open Access Journals (Sweden)

    Eduardo B. Saad

    2008-12-01

    Full Text Available Atrial fibrillation is associated with thromboembolic events that may cause important impairment on quality of life. Pulmonary vein isolation is the treatment of choice in cases that are refractory to medical therapy. Once sheaths and catheters are manipulated inside the left atrium, anticoagulation with heparin must be used during the procedure to protect patients from thromboembolic phenomena. Different strategies of anticoagulation are used at different centers. This review summarizes the pathophysiology of thrombus formation in the left atrium, defines which patients are under high risk and describes the main strategies used for anticoagulation.

  19. Unplanned pregnancy on a direct oral anticoagulant (Rivaroxaban): A warning.

    Science.gov (United States)

    Myers, B; Neal, R; Myers, O; Ruparelia, M

    2016-03-01

    Direct oral anticoagulants (DOACs or NOACs -non-vitamin K oral anticoagulants), as the name suggests, are oral anticoagulants with a direct inhibitory action either against factor X or factor II (thrombin). Pregnant women were excluded from participating in all the large trials of the DOACs and they are considered contra-indicated in pregnancy and breast feeding. We present a case of inadvertent exposure to rivaroxaban in a woman who presented at 25 weeks' gestation. The management of her pregnancy and delivery is described, and the previous published case reports are reviewed with a discussion about the use of DOACs in woman of childbearing age. PMID:27512489

  20. RNF4-Dependent Oncogene Activation by Protein Stabilization.

    Science.gov (United States)

    Thomas, Jane J; Abed, Mona; Heuberger, Julian; Novak, Rostislav; Zohar, Yaniv; Beltran Lopez, Angela P; Trausch-Azar, Julie S; Ilagan, Ma Xenia G; Benhamou, David; Dittmar, Gunnar; Kopan, Raphael; Birchmeier, Walter; Schwartz, Alan L; Orian, Amir

    2016-09-20

    Ubiquitylation regulates signaling pathways critical for cancer development and, in many cases, targets proteins for degradation. Here, we report that ubiquitylation by RNF4 stabilizes otherwise short-lived oncogenic transcription factors, including β-catenin, Myc, c-Jun, and the Notch intracellular-domain (N-ICD) protein. RNF4 enhances the transcriptional activity of these factors, as well as Wnt- and Notch-dependent gene expression. While RNF4 is a SUMO-targeted ubiquitin ligase, protein stabilization requires the substrate's phosphorylation, rather than SUMOylation, and binding to RNF4's arginine-rich motif domain. Stabilization also involves generation of unusual polyubiquitin chains and docking of RNF4 to chromatin. Biologically, RNF4 enhances the tumor phenotype and is essential for cancer cell survival. High levels of RNF4 mRNA correlate with poor survival of a subgroup of breast cancer patients, and RNF4 protein levels are elevated in 30% of human colon adenocarcinomas. Thus, RNF4-dependent ubiquitylation translates transient phosphorylation signal(s) into long-term protein stabilization, resulting in enhanced oncoprotein activation. PMID:27653698

  1. NRIP, a novel calmodulin binding protein, activates calcineurin to dephosphorylate human papillomavirus E2 protein.

    Science.gov (United States)

    Chang, Szu-Wei; Tsao, Yeou-Ping; Lin, Chia-Yi; Chen, Show-Li

    2011-07-01

    Previously, we found a gene named nuclear receptor interaction protein (NRIP) (or DCAF6 or IQWD1). We demonstrate that NRIP is a novel binding protein for human papillomavirus 16 (HPV-16) E2 protein. HPV-16 E2 and NRIP can directly associate into a complex in vivo and in vitro, and the N-terminal domain of NRIP interacts with the transactivation domain of HPV-16 E2. Only full-length NRIP can stabilize E2 protein and induce HPV gene expression, and NRIP silenced by two designed small interfering RNAs (siRNAs) decreases E2 protein levels and E2-driven gene expression. We found that NRIP can directly bind with calmodulin in the presence of calcium through its IQ domain, resulting in decreased E2 ubiquitination and increased E2 protein stability. Complex formation between NRIP and calcium/calmodulin activates the phosphatase calcineurin to dephosphorylate E2 and increase E2 protein stability. We present evidences for E2 phosphorylation in vivo and show that NRIP acts as a scaffold to recruit E2 and calcium/calmodulin to prevent polyubiquitination and degradation of E2, enhancing E2 stability and E2-driven gene expression. PMID:21543494

  2. Protein kinase domain of twitchin has protein kinase activity and an autoinhibitory region.

    Science.gov (United States)

    Lei, J; Tang, X; Chambers, T C; Pohl, J; Benian, G M

    1994-08-19

    Twitchin is a 753-kDa polypeptide located in the muscle A-bands of the nematode, Caenorhabditis elegans. It consists of multiple copies of both fibronectin III and immunoglobulin C2 domains and, near the C terminus, a protein kinase domain with greatest homology to the catalytic domains of myosin light chain kinases. We have expressed and purified from Escherichia coli twitchin's protein kinase catalytic core and flanking sequences that do not include fibronectin III and immunoglobulin C2 domains. The protein was shown to phosphorylate a model substrate and to undergo autophosphorylation. The autophosphorylation occurs at a slow rate, attaining a maximum at 3 h with a stoichiometry of about 1.0 mol of phosphate/mol of protein, probably through an intramolecular mechanism. Sequence analysis of proteolytically derived phosphopeptides revealed that autophosphorylation occurred N-terminal to the catalytic core, predominantly at Thr-5910, with possible minor sites at Ser5912 and/or Ser-5913. This portion of twitchin (residues 5890-6268) was also phosphorylated in vitro by protein kinase C in the absence of calcium and phosphotidylserine, but not by cAMP-dependent protein kinase. By comparing the activities of three twitchin segments, the enzyme appears to be inhibited by the 60-amino acid residues lying just C-terminal to the kinase catalytic core. Thus, like a number of other protein kinases including myosin light chain kinases, the twitchin kinase appears to be autoregulated. PMID:8063727

  3. Protein kinase C controls activation of the DNA integrity checkpoint

    Science.gov (United States)

    Soriano-Carot, María; Quilis, Inma; Bañó, M. Carmen; Igual, J. Carlos

    2014-01-01

    The protein kinase C (PKC) superfamily plays key regulatory roles in numerous cellular processes. Saccharomyces cerevisiae contains a single PKC, Pkc1, whose main function is cell wall integrity maintenance. In this work, we connect the Pkc1 protein to the maintenance of genome integrity in response to genotoxic stresses. Pkc1 and its kinase activity are necessary for the phosphorylation of checkpoint kinase Rad53, histone H2A and Xrs2 protein after deoxyribonucleic acid (DNA) damage, indicating that Pkc1 is required for activation of checkpoint kinases Mec1 and Tel1. Furthermore, Pkc1 electrophoretic mobility is delayed after inducing DNA damage, which reflects that Pkc1 is post-translationally modified. This modification is a phosphorylation event mediated by Tel1. The expression of different mammalian PKC isoforms at the endogenous level in yeast pkc1 mutant cells revealed that PKCδ is able to activate the DNA integrity checkpoint. Finally, downregulation of PKCδ activity in HeLa cells caused a defective activation of checkpoint kinase Chk2 when DNA damage was induced. Our results indicate that the control of the DNA integrity checkpoint by PKC is a mechanism conserved from yeast to humans. PMID:24792164

  4. The pleiotropic activity of heat-shock proteins

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    Arleta Kaźmierczuk

    2009-10-01

    Full Text Available Stress or heat-shock proteins (HSPs are highly conserved proteins present in cells of both prokaryotes and eukaryotes, providing them with protection from cellular and environmental stress factors. Based on molecular-weight, HSPs can be divided into the large (HSP100: 100–110 kDa and HSP90: 75–96 kDa, intermediate (HSP70: 66–78 kDa, HSP60, and HSP40, and small (sHSP: 8.5–40 kDa subfamilies. These proteins play an essential role as molecular chaperones/co-chaperones by assisting the correct folding of nascent and stress-accumulated protein-substrate assembly, preventing the aggregation of these proteins, as well as transport across membranes and the degradation of other proteins. Members of HSP family display dual activity depending on their intra- or extracellular distribution. Intracellular HSPs mainly play a protective role. Extracellular or membrane-bound HSPs mediate immunological functions. Among the functions of HSPs is their participation in cell signaling. This review deals with the structure and properties of the main members of the HSPs and their role in a large number of cellular/extracellular processes.

  5. Menthol reduces the anticoagulant effect of warfarin by inducing cytochrome P450 2C expression.

    Science.gov (United States)

    Hoshino, Motohiro; Ikarashi, Nobutomo; Tsukui, Makoto; Kurokawa, Asako; Naito, Rina; Suzuki, Midori; Yokobori, Kohsuke; Ochiai, Takumi; Ishii, Makoto; Kusunoki, Yoshiki; Kon, Risako; Ochiai, Wataru; Wakui, Nobuyuki; Machida, Yoshiaki; Sugiyama, Kiyoshi

    2014-06-01

    Recently, it was reported that the anticoagulant effect of warfarin was reduced when patients receiving warfarin also took menthol. The purpose of this study is to reveal the mechanism of this reduced anticoagulant effect of warfarin from the pharmacokinetic point of view. Warfarin was orally administered to mice 24h after the administration of menthol for 2 days, and the plasma warfarin concentration was measured. In the menthol administration group, the area under the blood concentration time curve of warfarin was decreased by approximately 25%, while total clearance was increased to 1.3-fold compared to the control group. The hepatic cytochrome P450 (CYP) 2C protein expression level in the menthol administration group was significantly increased compared to that in the control group. An increase in the nuclear translocation of constitutive androstane receptor (CAR) was also observed. The addition of menthol to human hepatic cells, HepaRG cells, caused an increase in the mRNA expression level of CYP2C9. The results of this study revealed that menthol causes an increase in CYP2C expression levels in the liver, which leads to an enhancement of warfarin metabolism, resulting in a decreased anticoagulant effect of warfarin. It was also suggested that menthol acted directly on the liver and increased the expression level of CYP2C by enhancing the nuclear translocation of CAR. PMID:24594507

  6. Na2EDTA anticoagulant impaired blood samples from the teleost Piaractus mesopotamicus

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    Thaís Heloisa Vaz Farias

    2016-05-01

    Full Text Available Abstract: The present study aimed to evaluate the effects of Na heparin and Na2EDTA on blood of Piaractus mesopotamicus (360.7±42.4g, 26.4±1.0cm. Twenty fishes were sampled in two experiment trials, ten for erythrocyte fragility analysis and ten for hematologic and plasma biochemical study. The blood collected by venous-caudal puncture was fractioned and stored in anticoagulants solution: Na2EDTA 10%, Na2EDTA 3%, Na heparin 5000 IU and Na heparin 100 IU. Plasmatic levels of calcium presented in the Na2EDTA stored samples were about 80% lower than both heparin groups. Blood samples of P. mesopotamicus stored with Na2EDTA demonstrated increase in the hematocrit and MCV, and decrease in MCHC. The dose-response effect was observed in this study. The results are reinforced by the higher levels of plasmatic protein and hemolysis presented in the Na2EDTA 10% stored blood, confirming the deleterious effect of this anticoagulant treatment on the quality of blood samples. Na2EDTA is not indicated to store P. mesopotamicus blood samples, but sodium heparin at 100 IU is the most recommended anticoagulant, since this treatment presented the lower rate of alterations in the stored blood.

  7. Heat Shock Protein 90 Indirectly Regulates ERK Activity by Affecting Raf Protein Metabolism

    Institute of Scientific and Technical Information of China (English)

    Fei DOU; Liu-Di YUAN; Jing-Jing ZHU

    2005-01-01

    Extracellular signal-regulated protein kinase (ERK) has been implicated in the pathogenesis of several nerve system diseases. As more and more kinases have been discovered to be the client proteins of the molecular chaperone Hsp90, the use of Hsp90 inhibitors to reduce abnormal kinase activity is a new treatment strategy for nerve system diseases. This study investigated the regulation of the ERK pathway by Hsp90. We showed that Hsp90 inhibitors reduce ERK phosphorylation without affecting the total ERK protein level. Further investigation showed that Raf, the upstream kinase in the Ras-Raf-MEK-ERK pathway,forms a complex with Hsp90 and Hsp70. Treating cells with Hsp90 inhibitors facilitates Raf degradation,thereby down-regulating the activity of ERK.

  8. Pharmacological activities in thermal proteins: relationships in molecular evolution

    Science.gov (United States)

    Fox, S. W.; Hefti, F.; Hartikka, J.; Junard, E.; Przybylski, A. T.; Vaughan, G.

    1987-01-01

    The model of protobiological events that has been presented in these pages has increasing relevance to pharmacological research. The thermal proteins that function as key substances in the proteinoid theory have recently been found to prolong the survival of rat forebrain neurons in culture and to stimulate the growth of neurites. A search for such activity in thermal proteins added to cultures of modern neurons was suggested by the fact that some of the microspheres assembled from proteinoids rich in hydrophobic amino acids themselves generate fibrous outgrowths.

  9. Considerations for long-term anticoagulant therapy in patients with venous thromboembolism in the novel oral anticoagulant era

    Directory of Open Access Journals (Sweden)

    Toth PP

    2016-02-01

    Full Text Available Peter P Toth1–3 1CGH Medical Center, Sterling, IL, 2Johns Hopkins University School of Medicine, Baltimore, MD, 3University of Illinois School of Medicine, Peoria, IL, USA Background: Patients who have had a venous thromboembolic event are generally advised to receive anticoagulant treatment for 3 months or longer to prevent a recurrent episode. Current guidelines recommend initial heparin and an oral vitamin K antagonist (VKA for long-term anticoagulation. However, because of the well-described disadvantages of VKAs, including extensive food and drug interactions and the need for regular anticoagulation monitoring, novel oral anticoagulants (NOACs have become an attractive option in recent years. These agents are given at fixed doses and do not require routine coagulation-time monitoring. The NOACs are discussed in this review with regard to the needs of patients on long-term anticoagulation. Methods: Current guidelines from Europe and North America that refer to the treatment of deep vein thrombosis and/or pulmonary embolism are included, as well as published randomized Phase III clinical trials of NOACs. PubMed searches were used for sourcing case studies of long-term anticoagulant treatment, and results were filtered for human application and screened for relevance. Conclusion: NOAC-based therapy showed a similar efficacy and safety profile to heparins/VKAs but without the need for regular anticoagulation monitoring or dietary adjustments, and can be taken as a fixed-dose regimen once or twice daily. This represents a significant step forward in facilitating the management of long-term anticoagulation therapy. Furthermore, in the EINSTEIN studies, improved patient satisfaction was documented with the NOAC rivaroxaban, which may result in better adherence to therapy and an overall reduction in the incidence of recurrent venous thromboembolism. Keywords: anticoagulation, patient needs, vitamin K antagonist, direct thrombin inhibitor, direct

  10. Thrombolytic-plus-Anticoagulant Therapy versus Anticoagulant-Alone Therapy in Submassive Pulmonary Thromboembolism (TVASPE Study: A Randomized Clinical Trial

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    Maryam Taherkhani

    2015-10-01

    Full Text Available Background: The use of thrombolytic agents in the treatment of hemodynamically stable patients with acute submassive pulmonary embolism (PTE remains controversial. We, therefore, conducted this study to compare the effect of thrombolytic plus anticoagulation versus anticoagulation alone on early death and adverse outcome following submassive PTE.Methods: We conducted a study of patients with acute pulmonary embolism and pulmonary hypertension or right ventricular dilatation/dysfunction but without arterial hypotension or shock. The patients were randomly assigned in a single-blind fashion to receive an anticoagulant [Enoxaparin (1 mg/kg twice a day] plus a thrombolytic [Alteplase (100 mg or Streptokinase (1500000 u/2 hours] or an anticoagulant [Enoxaparin (1 mg/kg twice a day] alone. The primary endpoint was in-hospital death or clinical deterioration requiring an escalation of treatment. The secondary endpoints of the study were major bleeding, pulmonary hypertension, right ventricular dilatation at the end of the first week, and exertional dyspnea at the end of the first month.Results: Of 50 patients enrolled, 25 patients were randomly assigned to receive an anticoagulant plus a thrombolytic and the other 25 patients were given an anticoagulant alone. The incidence of the primary endpoints was significantly higher in the anticoagulant-alone group than in the thrombolytic-plus-anticoagulant group (p value = 0.022. At the time of discharge, pulmonary artery pressure was significantly higher in the anticoagulant-alone group than in the thrombolytic- plus-anticoagulant group (p value = 0.018; however, reduction in the right ventricular size or normalization of the right ventricle showed non-significant differences between the two groups. There was no significant difference regarding the New York Heat Association (NYHA functional class between the two groups at the end of the first month (p value = 0.213. No fatal bleeding or cerebral bleeding

  11. L-Alanylglutamine inhibits signaling proteins that activate protein degradation, but does not affect proteins that activate protein synthesis after an acute resistance exercise.

    Science.gov (United States)

    Wang, Wanyi; Choi, Ran Hee; Solares, Geoffrey J; Tseng, Hung-Min; Ding, Zhenping; Kim, Kyoungrae; Ivy, John L

    2015-07-01

    Sustamine™ (SUS) is a dipeptide composed of alanine and glutamine (AlaGln). Glutamine has been suggested to increase muscle protein accretion; however, the underlying molecular mechanisms of glutamine on muscle protein metabolism following resistance exercise have not been fully addressed. In the present study, 2-month-old rats climbed a ladder 10 times with a weight equal to 75 % of their body mass attached at the tail. Rats were then orally administered one of four solutions: placebo (PLA-glycine = 0.52 g/kg), whey protein (WP = 0.4 g/kg), low dose of SUS (LSUS = 0.1 g/kg), or high dose of SUS (HSUS = 0.5 g/kg). An additional group of sedentary (SED) rats was intubated with glycine (0.52 g/kg) at the same time as the ladder-climbing rats. Blood samples were collected immediately after exercise and at either 20 or 40 min after recovery. The flexor hallucis longus (FHL), a muscle used for climbing, was excised at 20 or 40 min post exercise and analyzed for proteins regulating protein synthesis and degradation. All supplements elevated the phosphorylation of FOXO3A above SED at 20 min post exercise, but only the SUS supplements significantly reduced the phosphorylation of AMPK and NF-kB p65. SUS supplements had no effect on mTOR signaling, but WP supplementation yielded a greater phosphorylation of mTOR, p70S6k, and rpS6 compared with PLA at 20 min post exercise. However, by 40 min post exercise, phosphorylation of mTOR and rpS6 in PLA had risen to levels not different than WP. These results suggest that SUS blocks the activation of intracellular signals for MPB, whereas WP accelerates mRNA translation. PMID:25837301

  12. Lupus anticoagulant-hypoprothrombinemia syndrome: report of two cases and review of the literature.

    Science.gov (United States)

    Mulliez, S M N; De Keyser, F; Verbist, C; Vantilborgh, A; Wijns, W; Beukinga, I; Devreese, K M J

    2015-06-01

    Lupus anticoagulant-hypoprothrombinemia syndrome (LA-HPS) is a rare acquired disorder caused by prothrombin antibodies. The disease is most common in the pediatric age group (lupus erythematosus (SLE) and viral infections. The clinical manifestation of LA-HPS varies greatly in severity and it may cause severe life-threatening bleeding diathesis. LA-HPS is to be suspected when a patient presents with bleeding and a prolonged activated partial thromboplastin and prothrombin time, in combination with a lupus anticoagulant. The diagnosis is confirmed in the laboratory by identification of reduced prothrombin levels. There are no standardized recommendations for treatment of the hemorrhage associated with the syndrome; corticosteroids are used as first-line treatment. This review summarizes what is currently known about the pathogenesis, clinical features, diagnosis, treatment and prognosis of LA-HPS, and presents two case reports.

  13. Potential role of new anticoagulants for prevention and treatment of venous thromboembolism in cancer patients

    Directory of Open Access Journals (Sweden)

    Gómez-Outes A

    2013-05-01

    and treatment of VTE include parenteral compounds for once-daily administration (ie, semuloparin or once-weekly dosing (ie, idraparinux and idrabiotaparinux, as well as orally active compounds (ie, dabigatran, rivaroxaban, apixaban, edoxaban, betrixaban. In the present review, we discuss the pharmacology of the new anticoagulants, the results of clinical trials testing these new compounds in VTE, with special emphasis on studies that included cancer patients, and their potential advantages and drawbacks compared with existing therapies.Keywords: anticoagulants, venous thromboembolism, cancer, dabigatran, apixaban, rivaroxaban

  14. Efficient expression and purification of biologically active human cystatin proteins.

    Science.gov (United States)

    Chauhan, Sakshi; Tomar, Raghuvir S

    2016-02-01

    Cystatins are reversible cysteine protease inhibitor proteins. They are known to play important roles in controlling cathepsins, neurodegenerative disease, and in immune system regulation. Production of recombinant cystatin proteins is important for biochemical and function characterization. In this study, we cloned and expressed human stefin A, stefin B and cystatin C in Escherichia coli. Human stefin A, stefin B and cystatin C were purified from soluble fraction. For cystatin C, we used various chaperone plasmids to make cystatin C soluble, as it is reported to localize in inclusion bodies. Trigger factor, GroES-GroEL, DnaK-DnaJ-GrpE chaperones lead to the presence of cystatin C in the soluble fraction. Immobilized metal affinity chromatography, glutathione sepharose and anion exchange chromatography techniques were employed for efficient purification of these proteins. Their biological activities were tested by inhibition assays against cathepsin L and H3 protease.

  15. Modulation of the protein kinase activity of mTOR.

    Science.gov (United States)

    Lawrence, J C; Lin, T A; McMahon, L P; Choi, K M

    2004-01-01

    mTOR is a founding member of a family of protein kinases having catalytic domains homologous to those in phosphatidylinositol 3-OH kinase. mTOR participates in the control by insulin of the phosphorylation of lipin, which is required for adipocyte differentiation, and the two translational regulators, p70S6K and PHAS-I. The phosphorylation of mTOR, itself, is stimulated by insulin in Ser2448, a site that is also phosphorylated by protein kinase B (PKB) in vitro and in response to activation of PKB activity in vivo. Ser2448 is located in a short stretch of amino acids not found in the two TOR proteins in yeast. A mutant mTOR lacking this stretch exhibited increased activity, and binding of the antibody, mTAb-1, to this region markedly increased mTOR activity. In contrast, rapamycin-FKBP12 inhibited mTOR activity towards both PHAS-I and p70S6K, although this complex inhibited the phosphorylation of some sites more than that of others. Mutating Ser2035 to Ile in the FKBP12-rapamycin binding domain rendered mTOR resistant to inhibition by rapamycin. Unexpectedly, this mutation markedly decreased the ability of mTOR to phosphorylate certain sites in both PHAS-I and p70S6K. The results support the hypotheses that rapamycin disrupts substrate recognition instead of directly inhibiting phosphotransferase activity and that mTOR activity in cells is controlled by the phosphorylation of an inhibitory regulatory domain containing the mTAb-1 epitope. PMID:14560959

  16. Antioxidant, Antibacterial, and Cytoprotective Activity of Agathi Leaf Protein

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    A. S. Zarena

    2014-01-01

    Full Text Available In the present study a protein termed agathi leaf protein (ALP from Sesbania grandiflora Linn. (agathi leaves was isolated after successive precipitation with 65% ammonium sulphate followed by purification on Sephadex G 75. The column chromatography of the crude protein resulted in four peaks of which Peak I (P I showed maximum inhibition activity against hydroxyl radical. SDS-PAGE analysis of P I indicated that the molecular weight of the protein is ≈29 kDa. The purity of the protein was 98.4% as determined by RP-HPLC and showed a single peak with a retention time of 19.9 min. ALP was able to reduce oxidative damage by scavenging lipid peroxidation against erythrocyte ghost (85.50 ± 6.25%, linolenic acid (87.67 ± 3.14% at 4.33 μM, ABTS anion (88 ± 3.22%, and DNA damage (83 ± 4.20% at 3.44 μM in a dose-dependent manner. The purified protein offered significant protection to lymphocyte (72% at 30 min induced damage by t-BOOH. In addition, ALP showed strong antibacterial activity against Pseudomonas aeruginosa (20 ± 3.64 mm and Staphylococcus aureus (19 ± 1.53 mm at 200 μg/mL. The safety assessment showed that ALP does not induce cytotoxicity towards human lymphocyte at the tested concentration of 0.8 mg/mL.

  17. New anticoagulants for the prevention and treatment of venous thromboembolism

    Directory of Open Access Journals (Sweden)

    Simon J McRae

    2005-04-01

    Full Text Available Simon J McRae, Jeffrey S GinsbergDepartment of Medicine, McMaster University, Hamilton, ON, CanadaAbstract: Anticoagulant therapy is effective at preventing the development of venous thromboembolism in high-risk patients, and reduces morbidity and mortality in individuals with established thromboembolic disease. Vitamin K antagonists and heparins are currently the most commonly used anticoagulant drugs, but they have practical limitations. Therefore, new antithrombotic agents with predictable dose-responses (thereby decreasing the need for monitoring without compromising efficacy or safety, ideally available in an oral formulation and with a rapidly reversible anticoagulant effect, are needed. New drugs fulfilling some of the above criteria have been developed and have proven to be effective agents for the treatment and prevention of venous thromboembolism.Keywords: venous thromboembolism, anticoagulants, antithrombotic

  18. Citrate anticoagulation in the ICU: the Leeds experience.

    Science.gov (United States)

    Trumper, Charlotte

    2016-09-01

    Continuous renal replacement therapy (CRRT) is widely used in the management of critically ill patients with acute kidney injury. It requires effective anticoagulation of the extracorporeal blood circuit. Although heparin is the most commonly prescribed anticoagulant, there are issues associated with heparin, and there has been increasing interest in regional citrate anticoagulation as an alternative. In 2013, The Leeds Teaching Hospitals NHS Trust switched from heparin to citrate anticoagulant for CRRT in intensive care units (ICUs) across the Trust. This article examines the reasons for the switch, the implementation of citrate and the impact of this quality-improvement project in terms of patient outcome data and feedback from the ICU nursing team. PMID:27615524

  19. [Genetic predisposition to bleeding during oral anticoagulants treatment].

    Science.gov (United States)

    Montes Díaz, R; Nantes, O; Molina, E; Zozaya, J; Hermida, J

    2008-01-01

    The degree of anticoagulation obtained during oral anticoagulation therapy with vitamin K antagonists (VKA) varies among patients due to individual and environmental factors. The rate of anticoagulation influences the hemorrhagic risk. Therefore, it is plausible that patients specially sensitive to oral anticoagulants are at higher hemorrhagic risk, specially during the first weeks. The role of a series of polymorphisms of the enzymes involved in the metabolism of VKA or in the vitamin K cycle are reviewed. Three polymorphisms, two in the cytochrome P450 2C9 and one in the VKORC1 enzyme, are responsible for a high portion of the variability observed in the sensitivity to AVK. Although the available literature suggests that these genetic variants could increase the risk of severe hemorrhage, larger, well designed studies are needed to confirm this notion.

  20. How to manage new oral anticoagulants in case of surgery

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    Davide Imberti

    2013-12-01

    Full Text Available When a patient receiving new oral anticoagulants (NOACs requires an invasive procedure, the consequences of bleeding if anticoagulation is continued and the risk of thrombosis if it is omitted need to be carefully considered. In addition to the bleeding risk of the procedure, it is of paramount importance to evaluate the renal function, especially for dabigatran that is eliminated predominantly via the renal pathway. NOAC therapy should be stopped for at least 24 h before the intervention, and a longer interruption should be considered in cases of high bleeding risk procedures and/or renal failure. A base-line assessment of coagulation should be performed and intervention should be postponed (if possible if high levels of anticoagulation parameters are found. In the post-surgical period, if oral anticoagulant therapy cannot be re-started, patients should temporarily receive low molecular weight heparins and re-start NOACs as soon as possible.

  1. Eculizumab in paroxysmal nocturnal hemoglobinuria with Budd-Chiari syndrome progressing despite anticoagulation

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    Brodsky Andrés

    2012-09-01

    Full Text Available Abstract Paroxysmal nocturnal hemoglobinuria (PNH is a progressive, life-threatening disorder characterized by chronic intravascular hemolysis caused by uncontrolled complement activation. Hepatic vein thrombosis (Budd-Chiari syndrome is common in PNH patients. This case report describes the response to eculizumab (a humanized monoclonal antibody that inhibits terminal complement activation in a 25-year-old male with progressive liver function deterioration despite standard anticoagulation therapy and transjugular intrahepatic porto-systemic shunt. The patient presented with anemia, severe thrombocytopenia, headache, abdominal pain, and distention. He was diagnosed with PNH, cerebral vein thrombosis, and Budd-Chiari syndrome. Despite adequate anticoagulation, diuretic administration, and placement of a transjugular shunt, additional thrombotic events and progressive liver damage were observed. Eculizumab therapy was initiated, resulting in rapid blockade of intravascular hemolysis, increased platelet counts, ascites resolution, and liver function recovery, all of which are presently sustained. Since starting eculizumab the patient has had no further thrombotic events and his quality of life has dramatically improved. This is the first report to confirm the role of complement-mediated injury in the progression of Budd-Chiari syndrome in a patient with PNH. This case shows that terminal complement blockade with eculizumab can reverse progressive thromboses and hepatic failure that is unresponsive to anticoagulation therapy and suggests that early initiation of eculizumab should be included in the therapeutic regimen of patients with PNH-related Budd-Chiari syndrome.

  2. New direct oral anticoagulants--current therapeutic options and treatment recommendations for bleeding complications.

    Science.gov (United States)

    Miesbach, Wolfgang; Seifried, Erhard

    2012-10-01

    To date, clinical studies show that the incidence of spontaneous bleeding with new direct oral anticoagulants (DOAs) is comparable to that of established anticoagulants. However, unlike vitamin K antagonists, there are currently no clinically available antidotes or approved reversal agents for new DOAs. Restoring normal coagulation is important in many cases, such as emergency surgeries, serious bleedings, or anticoagulant overdosing. Attempts have been made to restore normal coagulation after treatment with new DOAs using compounds such as recombinant activated factor VII (rFVIIa), prothrombin complex concentrate (PCC), or FEIBA (factor eight inhibitor bypassing activity). Limited pre-clinical data and even less clinical evidence are available on the usefulness of these methods in restoring normal coagulation for the emergency management of critical bleeding episodes. Evaluating the utility of DOAs is further complicated by the fact that it is unknown how predictive established test systems are of the bleeding risks. Clinical practice requires further evaluation of the emergency management options for the new DOAs to define the agents and the doses that are most useful. Furthermore, patients receiving long-term treatment with a DOA are likely to undergo elective surgery at some point, and there is lack of evidence regarding perioperative treatment regimens under such conditions. This review summarises potential bleeding management options and available data on the new DOAs. PMID:22782297

  3. Novel Biosensor of Membrane Protein Proximity Based on Fluorogen Activated Proteins.

    Science.gov (United States)

    Vasilev, Kalin V; Gallo, Eugenio; Shank, Nathaniel; Jarvik, Jonathan W

    2016-01-01

    We describe a novel biosensor system for reporting proximity between cell surface proteins in live cultured cells. The biosensor takes advantage of recently developed fluorogen-activating proteins (FAPs) that display fluorescence only when bound to otherwise-nonfluorescent fluorogen molecules. To demonstrate feasibility for the approach, two recombinant rapamycin-binding proteins were expressed as single-pass plasma membrane proteins in HeLa cells; one of the proteins (scAvd- FRB) carried an extracellular avidin tag; the other (HL1-TO1-FKBP) carried an extracellular FAP. Cells were incubated with a membrane-impermeable bivalent ligand (biotin-PEG2000-DIR) consisting of biotin joined to a dimethyl-indole red (DIR) fluorogen by a polyethylene glycol linker, thus tethering the fluorogen to the scAvd-FRB fusion protein. Addition of rapamycin, which promotes FKBP-FRB dimerization and thereby brings the FAP in close proximity to the tethered fluorogen, led to a significant increase in DIR fluorescence. We call the new proximity assay TEFLA, for tethered fluorogen assay. PMID:27055753

  4. Membrane lipids regulate ganglioside GM2 catabolism and GM2 activator protein activity[S

    Science.gov (United States)

    Anheuser, Susi; Breiden, Bernadette; Schwarzmann, Günter; Sandhoff, Konrad

    2015-01-01

    Ganglioside GM2 is the major lysosomal storage compound of Tay-Sachs disease. It also accumulates in Niemann-Pick disease types A and B with primary storage of SM and with cholesterol in type C. Reconstitution of GM2 catabolism with β-hexosaminidase A and GM2 activator protein (GM2AP) at uncharged liposomal surfaces carrying GM2 as substrate generated only a physiologically irrelevant catabolic rate, even at pH 4.2. However, incorporation of anionic phospholipids into the GM2 carrying liposomes stimulated GM2 hydrolysis more than 10-fold, while the incorporation of plasma membrane stabilizing lipids (SM and cholesterol) generated a strong inhibition of GM2 hydrolysis, even in the presence of anionic phospholipids. Mobilization of membrane lipids by GM2AP was also inhibited in the presence of cholesterol or SM, as revealed by surface plasmon resonance studies. These lipids also reduced the interliposomal transfer rate of 2-NBD-GM1 by GM2AP, as observed in assays using Förster resonance energy transfer. Our data raise major concerns about the usage of recombinant His-tagged GM2AP compared with untagged protein. The former binds more strongly to anionic GM2-carrying liposomal surfaces, increases GM2 hydrolysis, and accelerates intermembrane transfer of 2-NBD-GM1, but does not mobilize membrane lipids. PMID:26175473

  5. Protein Kinase Cδ mediates the activation of Protein Kinase D2 in Platelets

    OpenAIRE

    Bhavanasi, Dheeraj; Kim, Soochong; Goldfinger, Lawrence E.; Kunapuli, Satya P.

    2011-01-01

    Protein Kinase D (PKD) is a subfamily of serine/threonine specific family of kinases, comprised of PKD1, PKD2 and PKD3 (PKCμ, PKD2 and PKCν in humans). It is known that PKCs activate PKD, but the relative expression of isoforms of PKD or the specific PKC isoform/s responsible for its activation in platelets is not known. This study is aimed at investigating the pathway involved in activation of PKD in platelets. We show that PKD2 is the major isoform of PKD that is expressed in human as well ...

  6. Stimulation of DNA Glycosylase Activities by XPC Protein Complex: Roles of Protein-Protein Interactions

    Directory of Open Access Journals (Sweden)

    Yuichiro Shimizu

    2010-01-01

    Full Text Available We showed that XPC complex, which is a DNA damage detector for nucleotide excision repair, stimulates activity of thymine DNA glycosylase (TDG that initiates base excision repair. XPC appeared to facilitate the enzymatic turnover of TDG by promoting displacement from its own product abasic site, although the precise mechanism underlying this stimulation has not been clarified. Here we show that XPC has only marginal effects on the activity of E. coli TDG homolog (EcMUG, which remains bound to the abasic site like human TDG but does not significantly interacts with XPC. On the contrary, XPC significantly stimulates the activities of sumoylated TDG and SMUG1, both of which exhibit quite different enzymatic kinetics from unmodified TDG but interact with XPC. These results point to importance of physical interactions for stimulation of DNA glycosylases by XPC and have implications in the molecular mechanisms underlying mutagenesis and carcinogenesis in XP-C patients.

  7. Novel Anticoagulants in Atrial Fibrillation: Monitoring, Reversal and Perioperative Management

    OpenAIRE

    Fadi Shamoun; Hiba Obeid; Harish Ramakrishna

    2015-01-01

    Atrial fibrillation continues to be a significant source of morbidity and mortality worldwide. Effective anticoagulation remains the cornerstone of outpatient and inpatient treatment. The use of the new generation of anticoagulants (NOACs) continues to grow. Recently published data indicate their cost-effectiveness and overall safety in stroke prevention; compared to vitamin K antagonists, they can be prescribed in fixed doses for long-term therapy without the need for coagulation monitoring....

  8. Anticoagulant Rodenticide Intoxication in Animals – A Review

    OpenAIRE

    VALCHEV, Ivan; Binev, Rumen; YORDANOVA, Veska; Nikolov, Yordan

    2008-01-01

    The newest measures for the control of harmful rodent populations are from the anticoagulant rodenticide group, which are divided into 2 subgroups: first and second generations, and indandione derivatives. Non-target organisms are potentially at risk of direct consumption of baits (primary hazard) and of eating poisoned rodents (secondary hazard). Anticoagulant rodenticides inhibit the enzyme vitamin K-dependent carboxylase and thus impair the reactivation of vitamin K1, indirectly affecting ...

  9. Use of antifibrinolytic mouthwash solution in anticoagulated oral surgery patients

    OpenAIRE

    Dimova, Cena; Evrosimovska, Biljana; Papakoca, Kiro; Georgiev, Zlatko; Angelovska, Bistra; Ristoska, Sonja

    2012-01-01

    Introduction:The ordinary treatment of anticoagulated patients includes the interruption of anticoagulant therapy for oral surgery interventions to prevent hemorrhage. However, this practice may logically increase the risk of a potentially life-threatening thromboembolism, so this issue is still controversial. The aim of the study was to evaluate the antifibrinolitic mouthwash solution (tranexamic acid) as a local haemostatic modality after oral surgery interventions. Methods:To realize the a...

  10. New perspectives and recommendations for anticoagulant therapy post orthopedic surgery

    OpenAIRE

    Marcelo Kropf; Cleidson Alves Bergami; Felipe Dias Leal; Claudia Oliveira Dias Passos; Zilda de Santana Gonsalves; Isabela Laudares Marques; Isabela Azevedo Mota; Marcele Lima Monte Gonçalves

    2011-01-01

    Anticoagulant therapy is essential for the prevention of risks associated with the formation of thrombus in patients after surgery, especially in orthopedics. Recently, new oral anticoagulants were introduced in the therapeutic arsenal. This fact is important, because the current drug of choice in clinical practice is enoxaparin, a low molecular weight heparin. As all injecting drugs, enoxaparin may reduce patients' adherence to treatment by dissatisfaction with and resistance to the administ...

  11. Adherence to a new oral anticoagulant treatment prescription: dabigatran etexilate

    Directory of Open Access Journals (Sweden)

    L Bellamy

    2009-07-01

    Full Text Available L Bellamy1, N Rosencher1, BI Eriksson21Anaesthesiology Department, Hôpital Cochin (AP-HP, René Descartes University, Paris 75014 France; 2Orthopaedic Department, University Hospital Sahlgrenska/Ostra, Gothenburg, SwedenAbstract: The recent development of new oral anticoagulants, of which dabigatran etexilate is currently at the most advanced stage of development, is the greatest advance in the provision of convenient anticoagulation therapy for many years. A new oral anticoagulation treatment, dabigatran etexilate, is already on the market in Europe. The main interest probably will be to improve the prescription and the adherence to an effective thromboprophylaxis in medical conditions such as atrial fibrillation without bleeding side effects, without the need for monitoring coagulation, and without drug and food interactions such as vitamin K anticoagulant (VKA treatment. Dabigatran is particularly interesting for extended thromboprophylaxis after major orthopedic surgery in order to avoid daily injection for a month. However, oral long-term treatments such as VKA are not systematically associated with a higher compliance level than injected treatments such as low-molecular-weight heparins. Indeed, adherence to an oral treatment, instead of the usual daily injection in major orthopedic surgery, is complex, and based not only on the frequency of dosing but also on patient motivation, understanding, and socio-economic status. New oral anticoagulants may be useful in this way but education and detection of risk factors of nonadherence to treatment are still essential.Keywords: oral anticoagulant, adherence, compliance, education, dabigatran

  12. Anticoagulation with recombinant hirudin and danaparoid sodium in pediatric patients.

    Science.gov (United States)

    Severin, Thomas; Zieger, Barbara; Sutor, Anton H

    2002-10-01

    Patients receiving heparin are at risk of developing heparin-induced thrombocytopenia (HIT). Whereas in HIT I only reversible mild thrombocytopenia occurs within the first days of heparin treatment, HIT II may lead to potentially life-threatening thromboembolic events. Pediatric patients suffering from HIT II have been reported in a study on newborns and in a few reports on children and adolescents. However, thrombotic complications can be as severe in children as they are in adults. In the case of HIT II, the withdrawal of heparin is required and alternative anticoagulation should be started. In contrast to numerous investigations in adult patients, including prospective studies, experience with alternative anticoagulants in pediatric patients is limited. The available data were analyzed according to HIT II complications, alternative anticoagulation, and clinical outcome. In conclusion, HIT II represents a potentially dangerous complication of heparin therapy in pediatric patients also. Alternative anticoagulation applied in pediatric patients mainly included danaparoid sodium and recombinant hirudin. In most patients treated with these anticoagulants, effective anticoagulation and clinical improvement were observed. Because of limited experience, more data are required for optimal management of HIT II in young patients. PMID:12420240

  13. [Duration of anticoagulant therapy in venous thromboembolic complications].

    Science.gov (United States)

    Kuznetsov, M R; Leontyev, S G; Neskhodimov, L A; Tolstikhin, V Yu; Khotinskiy, A A

    2016-01-01

    Adequate anticoagulant therapy is a general approach to treatment of deep vein thrombosis. However, the duration of anticoagulant therapy is not strictly specified in everyday clinical practice. The present article deals with various approaches to selecting the duration of therapy with anticoagulants based on the findings of studies, national and foreign clinical guidelines. The minimal duration of therapy for deep vein thrombosis and pulmonary thromboembolism amounts to 3 months in accordance with the national and American recommendations. For some cohorts of patients, continuation of therapy above 3 months is considered: patients with idiopathic thrombosis (the recommended duration of therapy of not less than 6 months), patients having persisting risk factor for relapse of thrombosis on termination of the main therapeutic course, oncological patients (6 month therapy followed by assessing the risk and benefit of continuing therapy with anticoagulants). Prolonged therapy of venous thromboembolism using unfractionated heparin or low-molecular-weight heparin followed by changing over to vitamin K antagonists is associated with decreased risk for thrombosis relapse approximately by 90%, however increasing the risk of haemorrhage. Currently, as an alternative, it is possible to consider administration of novel oral anticoagulants (rivaroxaban, dabigatran, apixaban) which beside high efficacy are associated with less risk of bleeding. The route of administration, no necessity to control the INR, and the minimal number of drug and food interactions make administration of new oral anticoagulants an attractive alternative to therapy with heparins and vitamin K antagonists. PMID:27100556

  14. New anticoagulants for the prevention of venous thromboembolism

    Science.gov (United States)

    Becattini, Cecilia; Lignani, Alessandra; Agnelli, Giancarlo

    2010-01-01

    Anticoagulant drugs have an essential role in the prevention and treatment of thromboembolic diseases. Currently available anticoagulants substantially reduce the incidence of thromboembolic events in a number of clinical conditions. However, these agents have limitations that strengthen the case for the development of new anticoagulants. An ideal anticoagulant should be at least as effective as those currently in use, as well as safe, simple to use, and widely applicable. The majority of new anticoagulants currently under investigation are small molecules with a selective and direct anti-Xa or antithrombin action, allowing oral administration in fixed doses. These new agents are in different phases of clinical development. The anti-Xa agent rivaroxaban and the antithrombin agent dabigatran are already available for the prophylaxis of venous thromboembolism in some countries. Apixaban is in an advanced phase of clinical development and several anti-Xa agents are currently approaching phase III clinical trials. Promising results in terms of efficacy and safety profiles have been obtained with these agents in different clinical conditions. Differences in pharmacokinetics and pharmacodynamics could offer the potential for individualized anticoagulant therapies in the near future. PMID:20531960

  15. Study on antibacterial activity of hydrogel from irradiated silk protein

    Energy Technology Data Exchange (ETDEWEB)

    Bunnak, J.; Chaisupakitsin, M. [King Mongkut' s Institute of Technology Lardkrabang, Bangkok (Thailand)

    2001-03-01

    Hydrogels for biomedical application were prepared from solution blends of 3% silk protein and 3%, 10% poly (vinyl alcohol) (PVA) and followed with irradiation. Mixture of hydrogels were gamma irradiated at 10, 20, 30, 40 and 50 kGy under N{sub 2} atmosphere. To clarify anti-bacterial activity of hydrogels, modified of the Agar disk diffusion method and American Association of Textile Chemists and Colorists, AATCC Test Method 90-1977, were carried out. The four kinds of bacteria such as Escherichia coli, Bacillus subtilis, Staphylococcus aureus and Staphylococcus epidermidis, were used. It was found that a 1:3 volume ratio of 3% silk protein and 3% PVA respectively, at 50 kGy irradiation, is suitable conditions for preparation hydrogels and trend to indicate the highest of an antibacterial activity against E. coli, B. subtilis and S. aureus. However the antibacterial activity of hydrogels against S. epidermidis was not clearly. These results are very useful to expand the application of hydrogel from irradiated silk protein to the medical products. (author)

  16. Negative regulation of lymphocyte activation by the adaptor protein LAX.

    Science.gov (United States)

    Zhu, Minghua; Granillo, Olivia; Wen, Renren; Yang, Kaiyong; Dai, Xuezhi; Wang, Demin; Zhang, Weiguo

    2005-05-01

    The membrane-associated adaptor protein LAX is a linker for activation of T cells (LAT)-like molecule that is expressed in lymphoid tissues. Upon stimulation of T or B cells, it is phosphorylated and interacts with Grb2 and the p85 subunit of PI3K. LAX, however, is not capable of replacing LAT in the TCR signaling pathway. In this study we report that upon T or B cell activation, the LAX protein was up-regulated dramatically. Although disruption of the LAX gene by homologous recombination had no major impact on lymphocyte development, it caused a significant reduction in CD23 expression on mature B cells. Interestingly, naive LAX(-/-) mice had spontaneous germinal center formation. Compared with normal T and B cells, LAX(-/-) T and B cells were hyperresponsive and had enhanced calcium flux, protein tyrosine phosphorylation, MAPK and Akt activation, and cell survival upon engagement of the T or B AgRs. Our data demonstrate that LAX functions as a negative regulator in lymphocyte signaling.

  17. Study on antibacterial activity of hydrogel from irradiated silk protein

    International Nuclear Information System (INIS)

    Hydrogels for biomedical application were prepared from solution blends of 3% silk protein and 3%, 10% poly (vinyl alcohol) (PVA) and followed with irradiation. Mixture of hydrogels were gamma irradiated at 10, 20, 30, 40 and 50 kGy under N2 atmosphere. To clarify anti-bacterial activity of hydrogels, modified of the Agar disk diffusion method and American Association of Textile Chemists and Colorists, AATCC Test Method 90-1977, were carried out. The four kinds of bacteria such as Escherichia coli, Bacillus subtilis, Staphylococcus aureus and Staphylococcus epidermidis, were used. It was found that a 1:3 volume ratio of 3% silk protein and 3% PVA respectively, at 50 kGy irradiation, is suitable conditions for preparation hydrogels and trend to indicate the highest of an antibacterial activity against E. coli, B. subtilis and S. aureus. However the antibacterial activity of hydrogels against S. epidermidis was not clearly. These results are very useful to expand the application of hydrogel from irradiated silk protein to the medical products. (author)

  18. Overinhibition of Mitogen-Activated Protein Kinase Inducing Tau Hyperphosphorylation

    Institute of Scientific and Technical Information of China (English)

    LI Hong-lian; CHEN Juan; LIU Shi-jie; ZHANG Jia-yu; WANG Qun; WANG Jian-zhi

    2005-01-01

    To reveal the relationship between mitogen-activated protein kinase (MAPK) and tau phosphorylation, we used different concentration of PD98059, an inhibitor of MEK (MAPK kinase), to treat mice neuroblastma (N2a) cell line for 6 h. It showed that the activity of MAPK decreased in a dose-dependent manner. But Western blot and immunofluorescence revealed that just when the cells were treated with 16 μmol/L PD98059, tau was hyperphosphorylated at Ser396/404 and Ser199/202 sites. We obtained the conclusion that overinhibited MAPK induced tau hyperphosphorylation at Ser396/404 and Ser199/202 sites.

  19. Effects of protein kinase C activators and staurosporine on protein kinase activity, cell survival, and proliferation in Tetrahymena thermophila

    DEFF Research Database (Denmark)

    Straarup, EM; Schousboe, P; Hansen, HQ;

    1997-01-01

    with either PMA or OAG, or at 2,500 cells ml-1. At 500 cells ml-1 PMA induced the in vivo phosphorylation of at least six proteins. The myelin basic protein fragment 4-14 was phosphorylated in vitro in crude extracts of a culture of 250,000 cells ml-1. Both the in vivo and the in vitro phosphorylation were......Autocrine factors prevent cell death in the ciliate Tetrahymena thermophila, a unicellular eukaryote, in a chemically defined medium. At certain growth conditions these factors are released at a sufficient concentration by > 500 cells ml-1 to support cell survival and proliferation. The protein...... kinase C activators phorbol 12-myristate 13-acetate (PMA) or 1-oleyl 2-acetate glycerol (OAG) when added to 250 cells ml-1 supported cell survival and proliferation. In the presence of the serine and threonine kinase inhibitor staurosporine the cells died both at 250 cells ml-1 in cultures supplemented...

  20. Molecular mechanism by which AMP-activated protein kinase activation promotes glycogen accumulation in muscle

    DEFF Research Database (Denmark)

    Hunter, Roger W; Treebak, Jonas Thue; Wojtaszewski, Jørgen;

    2011-01-01

    OBJECTIVE During energy stress, AMP-activated protein kinase (AMPK) promotes glucose transport and glycolysis for ATP production, while it is thought to inhibit anabolic glycogen synthesis by suppressing the activity of glycogen synthase (GS) to maintain the energy balance in muscle. Paradoxicall...... and subsequent rise in cellular [G6P]....

  1. Computational Modeling for the Activation Cycle of G-proteins by G-protein-coupled Receptors

    CERN Document Server

    Bao, Yifei; Glavy, Joseph; White, Tommy; 10.4204/EPTCS.40.4

    2010-01-01

    In this paper, we survey five different computational modeling methods. For comparison, we use the activation cycle of G-proteins that regulate cellular signaling events downstream of G-protein-coupled receptors (GPCRs) as a driving example. Starting from an existing Ordinary Differential Equations (ODEs) model, we implement the G-protein cycle in the stochastic Pi-calculus using SPiM, as Petri-nets using Cell Illustrator, in the Kappa Language using Cellucidate, and in Bio-PEPA using the Bio-PEPA eclipse plug in. We also provide a high-level notation to abstract away from communication primitives that may be unfamiliar to the average biologist, and we show how to translate high-level programs into stochastic Pi-calculus processes and chemical reactions.

  2. A new plastic collection tube made of polyethylene terephtalate is suitable for monitoring traditional anticoagulant therapy (oral anticoagulant, unfractionated heparin, and low molecular weight heparin).

    Science.gov (United States)

    Toulon, Pierre; Ajzenberg, Nadine; Smahi, Motalib; Guillin, Marie-Claude

    2007-01-01

    To improve the safety of blood collection, plastic tubes have been developed but various interactions with the coagulation system and/or antithrombotic drugs were reported with the first generation of such tubes. The aim of this multicentre study was to compare hemostasis test results measured in evacuated plastic tubes made of polyethylene terephtalate (VenoSafe, Terumo Europe) and in siliconized glass tubes containing the same citrate concentration (0.129 M). In addition, the impact of aging of the plastic tube was investigated by collecting blood samples in tubes at 8 months and at 1 month before expiry. Blood was drawn in 3 centres from untreated patients (n=269), patients on oral anticoagulant treatment (OAT, n=221), and patients treated with either unfractionated heparin (UFH, n=73) or a low molecular weight derivative (LMWH, n=48). Prothrombin time (PT) or INR, activated partial thromboplastin time (APTT) and anti-FXa activity were locally performed, when applicable. In untreated patients and in patients on OAT, PT and APTT values were found statistically shorter (p<0.05) when evaluated in plastic tubes than in glass tubes, except when PT was evaluated using a human thromboplastin. Surprisingly, significantly longer APTT and higher anti-FXa activities were obtained when blood from patients on UFH was drawn in plastic than in glass tubes. However, none of the differences had any clinical relevance (Bland-Altman analysis). In patients on anticoagulant treatment, there was no effect of aging of the plastic tubes. These results suggest that the plastic tube VenoSafe is suitable for coagulation testing both in untreated subjects and more interestingly in patients on traditional anticoagulant therapy during the whole shelf life indicated by the manufacturer. PMID:16426667

  3. Thrombolytic-plus-Anticoagulant Therapy versus Anticoagulant-Alone Therapy in Submassive Pulmonary Thromboembolism (TVASPE Study): A Randomized Clinical Trial

    OpenAIRE

    Maryam Taherkhani; Adineh Taherkhani; SeyedReza Hashemi; Taraneh Faghihi-Langroodi; Roxana Sadeghi; Mohammadreza Beyranvand

    2014-01-01

    Background: The use of thrombolytic agents in the treatment of hemodynamically stable patients with acute submassive pulmonary embolism (PTE) remains controversial. We, therefore, conducted this study to compare the effect of thrombolytic plus anticoagulation versus anticoagulation alone on early death and adverse outcome following submassive PTE.Methods: We conducted a study of patients with acute pulmonary embolism and pulmonary hypertension or right ventricular dilatation/dysfunction but w...

  4. Rapamycin induces mitogen-activated protein (MAP) kinase phosphatase-1 (MKP-1) expression through activation of protein kinase B and mitogen-activated protein kinase kinase pathways.

    Science.gov (United States)

    Rastogi, Ruchi; Jiang, Zhongliang; Ahmad, Nisar; Rosati, Rita; Liu, Yusen; Beuret, Laurent; Monks, Robert; Charron, Jean; Birnbaum, Morris J; Samavati, Lobelia

    2013-11-22

    Mitogen-activated protein kinase phosphatase-1 (MKP-1), also known as dual specificity phosphatase-1 (DUSP-1), plays a crucial role in the deactivation of MAPKs. Several drugs with immune-suppressive properties modulate MKP-1 expression as part of their mechanism of action. We investigated the effect of mTOR inhibition through rapamycin and a dual mTOR inhibitor (AZD2014) on MKP-1 expression. Low dose rapamycin led to a rapid activation of both AKT and ERK pathways with a subsequent increase in MKP-1 expression. Rapamycin treatment led to phosphorylation of CREB, transcription factor 1 (ATF1), and ATF2, three transcription factors that bind to the cyclic AMP-responsive elements on the Mkp-1 promoter. Inhibition of either the MEK/ERK or the AKT pathway attenuated rapamycin-mediated MKP-1 induction. AZD2014 did not activate AKT but activated the ERK pathway, leading to a moderate MKP-1 induction. Using bone marrow-derived macrophages (BMDMs) derived from wild-type (WT) mice or mice deficient in AKT1 and AKT2 isoforms or BMDM from targeted deficiency in MEK1 and MEK2, we show that rapamycin treatment led to an increased MKP1 expression in BMDM from WT but failed to do so in BMDMs lacking the AKT1 isoform or MEK1 and MEK2. Importantly, rapamycin pretreatment inhibited LPS-mediated p38 activation and decreased nitric oxide and IL-6 production. Our work provides a conceptual framework for the observed immune modulatory effect of mTOR inhibition.

  5. Anticoagulation reversal in the era of the non-vitamin K oral anticoagulants

    DEFF Research Database (Denmark)

    Enriquez, Andres; Lip, Gregory Y H; Baranchuk, Adrian

    2016-01-01

    In recent years, non-vitamin K oral anticoagulants (NOACs) have emerged as an alternative to warfarin for the prevention and treatment of thrombo-embolic disease. Large randomized trials have demonstrated that these agents, which act by directly targeting thrombin (dabigatran) and factor Xa....... New specific antidotes (e.g. idarucizumab, andexanet alfa, and ciraparantag) show promising data, and may soon become available for clinical use. In this article, we review the pharmacology of these agents, the incidence and outcomes of haemorrhagic complications, the available strategies for...

  6. Activated protein synthesis and suppressed protein breakdown signaling in skeletal muscle of critically ill patients.

    Directory of Open Access Journals (Sweden)

    Jakob G Jespersen

    Full Text Available BACKGROUND: Skeletal muscle mass is controlled by myostatin and Akt-dependent signaling on mammalian target of rapamycin (mTOR, glycogen synthase kinase 3β (GSK3β and forkhead box O (FoxO pathways, but it is unknown how these pathways are regulated in critically ill human muscle. To describe factors involved in muscle mass regulation, we investigated the phosphorylation and expression of key factors in these protein synthesis and breakdown signaling pathways in thigh skeletal muscle of critically ill intensive care unit (ICU patients compared with healthy controls. METHODOLOGY/PRINCIPAL FINDINGS: ICU patients were systemically inflamed, moderately hyperglycemic, received insulin therapy, and showed a tendency to lower plasma branched chain amino acids compared with controls. Using Western blotting we measured Akt, GSK3β, mTOR, ribosomal protein S6 kinase (S6k, eukaryotic translation initiation factor 4E binding protein 1 (4E-BP1, and muscle ring finger protein 1 (MuRF1; and by RT-PCR we determined mRNA expression of, among others, insulin-like growth factor 1 (IGF-1, FoxO 1, 3 and 4, atrogin1, MuRF1, interleukin-6 (IL-6, tumor necrosis factor α (TNF-α and myostatin. Unexpectedly, in critically ill ICU patients Akt-mTOR-S6k signaling was substantially higher compared with controls. FoxO1 mRNA was higher in patients, whereas FoxO3, atrogin1 and myostatin mRNAs and MuRF1 protein were lower compared with controls. A moderate correlation (r2=0.36, p<0.05 between insulin infusion dose and phosphorylated Akt was demonstrated. CONCLUSIONS/SIGNIFICANCE: We present for the first time muscle protein turnover signaling in critically ill ICU patients, and we show signaling pathway activity towards a stimulation of muscle protein synthesis and a somewhat inhibited proteolysis.

  7. Do novel oral anticoagulants do better than standard therapy in the treatment of deep vein thrombosis?

    Science.gov (United States)

    Brodmann, M

    2013-08-01

    The focus of DVT treatment is the prevention of recurrence and thrombus migration by treatment with anticoagulants. The aim is to improve outcomes by reducing clot burden and by preventing thrombus propagation, in order to prevent PE and the development of long-term complication. Actually, initial therapy is parenteral anticoagulation, mainly with low molecular weight heparin followed by a vitamin K antagonist (VKA) for triggered and idiopathic DVT. The long term treatment suggestion with a VKA is for sure the most challenging therapeutic scenario, showing all the disadvantages of VKA especially in the onset phase when therapeutic levels of VKA are difficult to achieve. The difference between VKAs and NOACs is the fact, that NOACs target a specific factor in the coagulation cascade. At time now two pathways have been chosen for treatment options, the direct inhibition of active sites of thrombin and factor Xa. Routine monitoring is not required and the drugs can be administered in fixed doses, which should increase patient adherence to long term treatment. At time now, four novel anticoagulants are called to be options for DVT treatment. Rivaroxaban, apixaban and edoxaban are direct FXa inhibitors, whereas dabigtran etexilate is a direct thrombin inhibitor. PMID:23681109

  8. H pylori stimulates proliferation of gastric cancer cells through activating mitogen-activated protein kinase cascade

    Institute of Scientific and Technical Information of China (English)

    Yong-Chang Chen; Ying Wang; Jing-Yan Li; Wen-Rong Xu; You-Li Zhang

    2006-01-01

    AIM: To explore the mechanism by which H pylori causes activation of gastric epithelial cells.METHODS: A VacA (+) and CagA (+) standard Hpyloriline NCTC 11637 and a human gastric adenocarcinoma derived gastric epithelial cell line BGC-823 were applied in the study. MTT assay and 3H-TdR incorporation test were used to detect the proliferation of BGC-823 cells and Western blotting was used to detect the activity and existence of related proteins.RESULTS: Incubation with Hpylori extract increased the proliferation of gastric epithelial cells, reflected by both live cell number and DNA synthesis rate. The activity of extracellular signal-regulated protein kinase (ERK) signal transduction cascade increased within 20 min after incubation with Hpylori extract and appeared to be a sustained event. MAPK/ERK kinase (MEK) inhibitor PD98059abolished the action of H pylori extract on both ERK activity and cell proliferation. Incubation with H pyloriextract increased c-Fos expression and SRE-dependentgene expression. H pylori extract caused phosphorylation of several proteins including a protein with molecular size of 97.4 kDa and tyrosine kinase inhibitor genistein inhibited the activation of ERK and the proliferation of cells caused by H pylori extract.CONCLUSION: Biologically active elements in H pylori extract cause proliferation of gastric epithelial cells through activating tyrosine kinase and ERK signal transduction cascade.

  9. New oral anticoagulants: an emergency department overview.

    Science.gov (United States)

    Wood, Peter

    2013-12-01

    As of September 2013, three new oral anticoagulants (NOACs) are now available for clinical use on the Pharmaceutical Benefits Scheme in Australia. All three are for stroke prevention in atrial fibrillation, and one will also be available for the treatment of deep venous thrombosis and pulmonary embolism. All have been evaluated in large, multicentre randomised clinical trials. These drugs show at least equivalent efficacy to the current standard of care, the vitamin K antagonist warfarin. Major bleeding rates are overall comparable with warfarin, but there is an important reduction in intracranial bleeding of approximately 50% with all NOAC agents. The NOACs are administered in a simple, fixed dose regimen. There are a few clinically important interactions with other medications or diet. Concerns exist about the potential for irreversible bleeding in the small number of patients in which that occurs. This short report will discuss the pharmacology of these agents, the indications for use, aspects of laboratory monitoring and the management of bleeding with these agents. PMID:24224462

  10. New oral anticoagulants: will they replace warfarin?

    Science.gov (United States)

    Little, James W

    2012-05-01

    Vitamin K antagonists, such as warfarin, are considered to be the treatment of choice to prevent thromboembolic events, but problems, such as the need for frequent dose adjustment and monitoring of coagulation status, as well as multiple drug and food interactions, make their use difficult for both physician and patient. Two new anticoagulants are now being considered as possible replacements of vitamin K antagonists. Dabigatran, an oral direct thrombin inhibitor has already been approved in the USA for prevention of stroke in patients with atrial fibrillation. Rivaroxaban, a factor Xa inhibitor, and dabigatran are licensed in Europe and Canada for short-term thromboprophylaxis after elective hip or knee replacement surgery. The advantages of these drugs are that they are safe and effective, require no monitoring, have a direct mode of action against only one clotting factor (thrombin or factor Xa), have limited drug interactions, and have rapid peak blood levels. Based on the fact that dabigatran has already been approved for use in the USA, it would appear that it has an advantage over rivaroxaban in becoming the replacement drug for vitamin K antagonists. PMID:22668618

  11. Berberine Promotes Glucose Consumption Independently of AMP-Activated Protein Kinase Activation

    OpenAIRE

    Miao Xu; Yuanyuan Xiao; Jun Yin; Wolin Hou; Xueying Yu; Li Shen; Fang Liu; Li Wei; Weiping Jia

    2014-01-01

    Berberine is a plant alkaloid with anti-diabetic action. Activation of AMP-activated protein kinase (AMPK) pathway has been proposed as mechanism for berberine's action. This study aimed to examine whether AMPK activation was necessary for berberine's glucose-lowering effect. We found that in HepG2 hepatocytes and C2C12 myotubes, berberine significantly increased glucose consumption and lactate release in a dose-dependent manner. AMPK and acetyl coenzyme A synthetase (ACC) phosphorylation wer...

  12. Involvement of Hypothalamic AMP-Activated Protein Kinase in Leptin-Induced Sympathetic Nerve Activation

    OpenAIRE

    Mamoru Tanida; Naoki Yamamoto; Toshishige Shibamoto; Kamal Rahmouni

    2013-01-01

    In mammals, leptin released from the white adipose tissue acts on the central nervous system to control feeding behavior, cardiovascular function, and energy metabolism. Central leptin activates sympathetic nerves that innervate the kidney, adipose tissue, and some abdominal organs in rats. AMP-activated protein kinase (AMPK) is essential in the intracellular signaling pathway involving the activation of leptin receptors (ObRb). We investigated the potential of AMPKα2 in the sympathetic effec...

  13. Cordycepin activates AMP-activated protein kinase (AMPK) via interaction with the γ1 subunit

    OpenAIRE

    Wu, Chongming; Guo, Yanshen; Su, Yan; Zhang, Xue; Luan, Hong; Zhang, Xiaopo; Zhu, Huixin; He, Huixia; Wang, Xiaoliang; Sun, Guibo; Sun, Xiaobo; Guo, Peng; Zhu, Ping

    2013-01-01

    Cordycepin is a bioactive component of the fungus Cordyceps militaris. Previously, we showed that cordycepin can alleviate hyperlipidemia through enhancing the phosphorylation of AMP-activated protein kinase (AMPK), but the mechanism of this stimulation is unknown. Here, we investigated the potential mechanisms of cordycepin-induced AMPK activation in HepG2 cells. Treatment with cordycepin largely reduced oleic acid (OA)-elicited intracellular lipid accumulation and increased AMPK activity in...

  14. Superoxide dismutase activity of Cu-bound prion protein

    Science.gov (United States)

    Hodak, Miroslav; Lu, Wenchang; Bernholc, Jerry

    2009-03-01

    Misfolding of the prion protein, PrP, has been linked to a group of neurodegenerative diseases, including the mad cow disease in cattle and the Creutzfeldt-Jakob disease in humans. The normal function of PrP is still unknown, but it was found that the PrP can efficiently bind Cu(II) ions. Early experiments suggested that Cu-PrP complex possesses significant superoxide dismutase (SOD) activity, but later experiments failed to confirm it and at present this issue remains unresolved. Using a recently developed hybrid DFT/DFT method, which combines Kohn-Sham DFT for the solute and its first solvation shells with orbital-free DFT for the remainder of the solvent, we have investigated SOD activity of PrP. The PrP is capable of incorporating Cu(II) ions in several binding modes and our calculations find that each mode has a different SOD activity. The highest activity found is comparable to those of well-known SOD proteins, suggesting that the conflicting experimental results may be due to different bindings of Cu(II) in those experiments.

  15. Activity of lactoperoxidase when adsorbed on protein layers.

    Science.gov (United States)

    Haberska, Karolina; Svensson, Olof; Shleev, Sergey; Lindh, Liselott; Arnebrant, Thomas; Ruzgas, Tautgirdas

    2008-09-15

    Lactoperoxidase (LPO) is an enzyme, which is used as an antimicrobial agent in a number of applications, e.g., food technology. In the majority of applications LPO is added to a homogeneous product phase or immobilised on product surface. In the latter case, however, the measurements of LPO activity are seldom reported. In this paper we have assessed LPO enzymatic activity on bare and protein modified gold surfaces by means of electrochemistry. It was found that LPO rapidly adsorbs to bare gold surfaces resulting in an amount of LPO adsorbed of 2.9mg/m(2). A lower amount of adsorbed LPO is obtained if the gold surface is exposed to bovine serum albumin, bovine or human mucin prior to LPO adsorption. The enzymatic activity of the adsorbed enzyme is in general preserved at the experimental conditions and varies only moderately when comparing bare gold and gold surface pretreated with the selected proteins. The measurement of LPO specific activity, however, indicate that it is about 1.5 times higher if LPO is adsorbed on gold surfaces containing a small amount of preadsorbed mucin in comparison to the LPO directly adsorbed on bare gold.

  16. Activated G Protein Gαs Samples Multiple Endomembrane Compartments.

    Science.gov (United States)

    Martin, Brent R; Lambert, Nevin A

    2016-09-23

    Heterotrimeric G proteins are localized to the plasma membrane where they transduce extracellular signals to intracellular effectors. G proteins also act at intracellular locations, and can translocate between cellular compartments. For example, Gαs can leave the plasma membrane and move to the cell interior after activation. However, the mechanism of Gαs translocation and its intracellular destination are not known. Here we use bioluminescence resonance energy transfer (BRET) to show that after activation, Gαs rapidly associates with the endoplasmic reticulum, mitochondria, and endosomes, consistent with indiscriminate sampling of intracellular membranes from the cytosol rather than transport via a specific vesicular pathway. The primary source of Gαs for endosomal compartments is constitutive endocytosis rather than activity-dependent internalization. Recycling of Gαs to the plasma membrane is complete 25 min after stimulation is discontinued. We also show that an acylation-deacylation cycle is important for the steady-state localization of Gαs at the plasma membrane, but our results do not support a role for deacylation in activity-dependent Gαs internalization. PMID:27528603

  17. Conservation, variability and the modeling of active protein kinases.

    Directory of Open Access Journals (Sweden)

    James D R Knight

    Full Text Available The human proteome is rich with protein kinases, and this richness has made the kinase of crucial importance in initiating and maintaining cell behavior. Elucidating cell signaling networks and manipulating their components to understand and alter behavior require well designed inhibitors. These inhibitors are needed in culture to cause and study network perturbations, and the same compounds can be used as drugs to treat disease. Understanding the structural biology of protein kinases in detail, including their commonalities, differences and modes of substrate interaction, is necessary for designing high quality inhibitors that will be of true use for cell biology and disease therapy. To this end, we here report on a structural analysis of all available active-conformation protein kinases, discussing residue conservation, the novel features of such conservation, unique properties of atypical kinases and variability in the context of substrate binding. We also demonstrate how this information can be used for structure prediction. Our findings will be of use not only in understanding protein kinase function and evolution, but they highlight the flaws inherent in kinase drug design as commonly practiced and dictate an appropriate strategy for the sophisticated design of specific inhibitors for use in the laboratory and disease therapy.

  18. Lupus anticoagulant is significantly associated with inflammatory reactions in patients with suspected deep vein thrombosis

    DEFF Research Database (Denmark)

    Sidelmann, Johannes Jakobsen; Sjøland, Jonas A.; Gram, Jørgen;

    2007-01-01

    OBJECTIVE: Lupus anticoagulant (LA) and antiphospholipid antibodies (aPL) are suggested as risk factors for development of deep vein thrombosis (DVT) among patients without systemic lupus erythematosus (SLE). Other conditions, e.g. inflammation, are reported to induce LA and it is uncertain whether...... of the International Society of Thrombosis and Haemostasis. The concentration of anticardiolipin (aCL) and beta(2)-glycoprotein I (anti-beta(2)-GPI) antibodies as well as C-reactive protein (CRP) was determined with sensitive and precise methods. RESULTS: LA was demonstrated in 8 patients with DVT and in 10 patients...

  19. Hepatitis B virus x protein induces autophagy via activating death-associated protein kinase.

    Science.gov (United States)

    Zhang, H-T; Chen, G G; Hu, B-G; Zhang, Z-Y; Yun, J-P; He, M-L; Lai, P B S

    2014-01-01

    Hepatitis B virus x protein (HBX), a product of hepatitis B virus (HBV), is a multifunctional protein that regulates viral replication and various cellular functions. Recently, HBX has been shown to induce autophagy; however, the responsible mechanism is not fully known. In this study, we established stable HBX-expressing epithelial Chang cells as the platform to study how HBX induced autophagy. The results showed that the overexpression of HBX resulted in starvation-induced autophagy. HBX-induced autophagy was related to its ability to dephosphorylate/activate death-associated protein kinase (DAPK). The block of DAPK by its siRNA significantly counteracted HBX-mediated autophagy, confirming the positive role of DAPK in this process. HBX also induced Beclin 1, which functions at the downstream of the DAPK-mediated autophagy pathway. Although HBX could activate JNK, a kinase known to participate in autophagy in certain conditions, the change in JNK failed to influence HBX-induced autophagy. In conclusion, HBX induces autophagy via activating DAPK in a pathway related to Beclin 1, but not JNK. This new finding should help us to understand the role of autophagy in HBX-mediated pathogenesis and thus may provide targets for intervening HBX-related disorders.

  20. TALE factors poise promoters for activation by Hox proteins.

    Science.gov (United States)

    Choe, Seong-Kyu; Ladam, Franck; Sagerström, Charles G

    2014-01-27

    Hox proteins form complexes with TALE cofactors from the Pbx and Prep/Meis families to control transcription, but it remains unclear how Hox:TALE complexes function. Examining a Hoxb1b:TALE complex that regulates zebrafish hoxb1a transcription, we find maternally deposited TALE proteins at the hoxb1a promoter already during blastula stages. These TALE factors recruit histone-modifying enzymes to promote an active chromatin profile at the hoxb1a promoter and also recruit RNA polymerase II (RNAPII) and P-TEFb. However, in the presence of TALE factors, RNAPII remains phosphorylated on serine 5 and hoxb1a transcription is inefficient. By gastrula stages, Hoxb1b binds together with TALE factors to the hoxb1a promoter. This triggers P-TEFb-mediated transitioning of RNAPII to the serine 2-phosphorylated form and efficient hoxb1a transcription. We conclude that TALE factors access promoters during early embryogenesis to poise them for activation but that Hox proteins are required to trigger efficient transcription.

  1. Pros and cons of new oral anticoagulants in the treatment of venous thromboembolism in patients with cancer.

    Science.gov (United States)

    Verso, Melina; Agnelli, Giancarlo; Prandoni, Paolo

    2015-09-01

    Patients with cancer account for 20 % of cases of venous thromboembolism (VTE). Cancer patients are at increased risk for VTE during the entire course of their disease, also in absence of traditional VTE risk factors. Furthermore, patients with VTE and cancer have an estimated risk of bleeding of 15-20 % per year while on anticoagulant treatment. For these reasons, treatment of acute VTE in patients with cancer remains a clinical challenge. In clinical studies, which included about 27,000 patients, new oral anticoagulants (NOACs) have been shown to be as effective and safe as conventional anticoagulation (heparin given with and followed by vitamin K antagonists) for the treatment of VTE. In these studies, 1227 patients with active cancer were enrolled. Preliminary results of subgroup analyses and meta-analyses of randomized clinical trials suggest that NOACs could represent an alternative to conventional anticoagulation in patients with active cancer. Further "ad hoc" studies evaluating the clinical benefit of treatment with NOACs in patients with VTE and cancer are needed. PMID:25840679

  2. Fluctuation driven active molecular transport in passive channel proteins

    Science.gov (United States)

    Kosztin, Ioan

    2006-03-01

    Living cells interact with their extracellular environment through the cell membrane, which acts as a protective permeability barrier for preserving the internal integrity of the cell. However, cell metabolism requires controlled molecular transport across the cell membrane, a function that is fulfilled by a wide variety of transmembrane proteins, acting as either passive or active transporters. In this talk it is argued that, contrary to the general belief, in active cell membranes passive and spatially asymmetric channel proteins can act as active transporters by consuming energy from nonequilibrium fluctuations fueled by cell metabolism. This assertion is demonstrated in the case of the E. coli aquaglyceroporin GlpF channel protein, whose high resolution crystal structure is manifestly asymmetric. By calculating the glycerol flux through GlpF within the framework of a stochastic model, it is found that, as a result of channel asymmetry, glycerol uptake driven by a concentration gradient is enhanced significantly in the presence of non-equilibrium fluctuations. Furthermore, the enhancement caused by a ratchet-like mechanism is larger for the outward, i.e., from the cytoplasm to the periplasm, flux than for the inward one, suggesting that the same non-equilibrium fluctuations also play an important role in protecting the interior of the cell against poisoning by excess uptake of glycerol. Preliminary data on water and sugar transport through aquaporin and maltoporin channels, respectively, are indicative of the universality of the proposed nonequilibrium-fluctuation-driven active transport mechanism. This work was supported by grants from the Univ. of Missouri Research Board, the Institute for Theoretical Sciences and the Department of Energy (DOE Contract W-7405-ENG-36), and the National Science Foundation (FIBR-0526854).

  3. Refolding techniques for recovering biologically active recombinant proteins from inclusion bodies.

    Science.gov (United States)

    Yamaguchi, Hiroshi; Miyazaki, Masaya

    2014-02-20

    Biologically active proteins are useful for studying the biological functions of genes and for the development of therapeutic drugs and biomaterials in a biotechnology industry. Overexpression of recombinant proteins in bacteria, such as Escherichia coli, often results in the formation of inclusion bodies, which are protein aggregates with non-native conformations. As inclusion bodies contain relatively pure and intact proteins, protein refolding is an important process to obtain active recombinant proteins from inclusion bodies. However, conventional refolding methods, such as dialysis and dilution, are time consuming and, often, recovered yields of active proteins are low, and a trial-and-error process is required to achieve success. Recently, several approaches have been reported to refold these aggregated proteins into an active form. The strategies largely aim at reducing protein aggregation during the refolding procedure. This review focuses on protein refolding techniques using chemical additives and laminar flow in microfluidic chips for the efficient recovery of active proteins from inclusion bodies.

  4. Mycobacteriophage putative GTPase-activating protein can potentiate antibiotics.

    Science.gov (United States)

    Yan, Shuangquan; Xu, Mengmeng; Duan, Xiangke; Yu, Zhaoxiao; Li, Qiming; Xie, Longxiang; Fan, Xiangyu; Xie, Jianping

    2016-09-01

    The soaring incidences of infection by antimicrobial resistant (AR) pathogens and shortage of effective antibiotics with new mechanisms of action have renewed interest in phage therapy. This scenario is exemplified by resistant tuberculosis (TB), caused by resistant Mycobacterium tuberculosis. Mycobacteriophage SWU1 A321_gp67 encodes a putative GTPase-activating protein. Mycobacterium smegmatis with gp67 overexpression showed changed colony formation and biofilm morphology and supports the efficacy of streptomycin and capreomycin against Mycobacterium. gp67 down-regulated the transcription of genes involved in cell wall and biofilm development. To our knowledge, this is the first report to show that phage protein in addition to lysin or recombination components can synergize with existing antibiotics. Phage components might represent a promising new clue for better antibiotic potentiators. PMID:27345061

  5. Metals in the active site of native protein phosphatase-1.

    Science.gov (United States)

    Heroes, Ewald; Rip, Jens; Beullens, Monique; Van Meervelt, Luc; De Gendt, Stefan; Bollen, Mathieu

    2015-08-01

    Protein phosphatase-1 (PP1) is a major protein Ser/Thr phosphatase in eukaryotic cells. Its activity depends on two metal ions in the catalytic site, which were identified as manganese in the bacterially expressed phosphatase. However, the identity of the metal ions in native PP1 is unknown. In this study, total reflection X-ray fluorescence (TXRF) was used to detect iron and zinc in PP1 that was purified from rabbit skeletal muscle. Metal exchange experiments confirmed that the distinct substrate specificity of recombinant and native PP1 is determined by the nature of their associated metals. We also found that the iron level associated with native PP1 is decreased by incubation with inhibitor-2, consistent with a function of inhibitor-2 as a PP1 chaperone. PMID:25890482

  6. Increased mortality in patients with the lupus anticoagulant: the Vienna Lupus Anticoagulant and Thrombosis Study (LATS).

    Science.gov (United States)

    Gebhart, Johanna; Posch, Florian; Koder, Silvia; Perkmann, Thomas; Quehenberger, Peter; Zoghlami, Claudia; Ay, Cihan; Pabinger, Ingrid

    2015-05-28

    Data on the clinical course of lupus anticoagulant (LA)-positive individuals with or without thrombotic manifestations or pregnancy complications are limited. To investigate mortality rates and factors that might influence mortality, we conducted a prospective observational study of LA-positive individuals. In total, 151 patients (82% female) were followed for a median of 8.2 years; 30 of the patients (20%) developed 32 thromboembolic events (15 arterial and 17 venous events) and 20 patients (13%) died. In univariable analysis, new onset of thrombosis (hazard ratio [HR] = 8.76; 95% confidence interval [CI], 3.46-22.16) was associated with adverse survival. Thrombosis remained a strong adverse prognostic factor after multivariable adjustment for age and hypertension (HR = 5.95; 95% CI, 2.43-14.95). Concomitant autoimmune diseases, anticoagulant treatment at baseline, or positivity for anticardiolipin- or anti-β2-glycoprotein I antibodies were not associated with mortality. In a relative survival analysis, our cohort of LA positives showed a persistently worse survival in comparison with an age-, sex-, and study-inclusion-year-matched Austrian reference population. The cumulative relative survival was 95.0% (95% CI, 88.5-98.8) after 5 years and 87.7% (95% CI, 76.3-95.6) after 10 years. We conclude that occurrence of a thrombotic event is associated with higher mortality in patients with LA. Consequently, the prevention of thromboembolic events in LA positives might improve survival.

  7. Major cerebral events in Staphylococcus aureus infective endocarditis: is anticoagulant therapy safe?

    DEFF Research Database (Denmark)

    Rasmussen, Rasmus V; Snygg-Martin, Ulrika; Olaison, Lars;

    2009-01-01

    OBJECTIVES: To study the impact of anticoagulation on major cerebral events in patients with left-sided Staphylococcus aureus infective endocarditis (IE). METHODS: A prospective cohort study; the use of anticoagulation and the relation to major cerebral events was evaluated separately at onset......-hospital mortality was 23% (95% CI: 17-29%), and there was no significant difference between those with or without anticoagulation. CONCLUSIONS: We found no increased risk of cerebral haemorrhage in S. aureus IE patients receiving anticoagulation. Anticoagulation was associated with a reduced risk of cerebral events...... before initiation of antibiotics. Data support the continuance of anticoagulation in S. aureus IE patients when indicated....

  8. Amygdala kindling alters protein kinase C activity in dentate gyrus.

    Science.gov (United States)

    Chen, S J; Desai, M A; Klann, E; Winder, D G; Sweatt, J D; Conn, P J

    1992-11-01

    Kindling is a use-dependent form of synaptic plasticity and a widely used model of epilepsy. Although kindling has been widely studied, the molecular mechanisms underlying induction of this phenomenon are not well understood. We determined the effect of amygdala kindling on protein kinase C (PKC) activity in various regions of rat brain. Kindling stimulation markedly elevated basal (Ca(2+)-independent) and Ca(2+)-stimulated phosphorylation of an endogenous PKC substrate (which we have termed P17) in homogenates of dentate gyrus, assayed 2 h after kindling stimulation. The increase in P17 phosphorylation appeared to be due at least in part to persistent PKC activation, as basal PKC activity assayed in vitro using an exogenous peptide substrate was increased in kindled dentate gyrus 2 h after the last kindling stimulation. A similar increase in basal PKC activity was observed in dentate gyrus 2 h after the first kindling stimulation. These results document a kindling-associated persistent PKC activation and suggest that the increased activity of PKC could play a role in the induction of the kindling effect.

  9. Protein kinase D activity controls endothelial nitric oxide synthesis.

    Science.gov (United States)

    Aicart-Ramos, Clara; Sánchez-Ruiloba, Lucía; Gómez-Parrizas, Mónica; Zaragoza, Carlos; Iglesias, Teresa; Rodríguez-Crespo, Ignacio

    2014-08-01

    Vascular endothelial growth factor (VEGF) regulates key functions of the endothelium, such as angiogenesis or vessel repair in processes involving endothelial nitric oxide synthase (eNOS) activation. One of the effector kinases that become activated in endothelial cells upon VEGF treatment is protein kinase D (PKD). Here, we show that PKD phosphorylates eNOS, leading to its activation and a concomitant increase in NO synthesis. Using mass spectrometry, we show that the purified active kinase specifically phosphorylates recombinant eNOS on Ser1179. Treatment of endothelial cells with VEGF or phorbol 12,13-dibutyrate (PDBu) activates PKD and increases eNOS Ser1179 phosphorylation. In addition, pharmacological inhibition of PKD and gene silencing of both PKD1 and PKD2 abrogate VEGF signaling, resulting in a clear diminished migration of endothelial cells in a wound healing assay. Finally, inhibition of PKD in mice results in an almost complete disappearance of the VEGF-induced vasodilatation, as monitored through determination of the diameter of the carotid artery. Hence, our data indicate that PKD is a new regulatory kinase of eNOS in endothelial cells whose activity orchestrates mammalian vascular tone. PMID:24928905

  10. Plasma cholesteryl ester transfer protein mass and phospholipid transfer protein activity are associated with leptin in type 2 diabetes mellitus

    NARCIS (Netherlands)

    Dullaart, R. P. F.; de Vries, R.; Dallinga-Thie, G. M.; van Tol, A.; Sluiter, W. J.

    2007-01-01

    Adipose tissue contributes to plasma levels of lipid transfer proteins and is also the major source of plasma adipokines. We hypothesized that plasma cholesteryl ester transfer protein (CETP) mass, phospholipid transfer protein (PLTP) activity and cholesteryl ester transfer (CET, a measure of CETP a

  11. Egg Activation at Fertilization by a Soluble Sperm Protein.

    Science.gov (United States)

    Swann, Karl; Lai, F Anthony

    2016-01-01

    The most fundamental unresolved issue of fertilization is to define how the sperm activates the egg to begin embryo development. Egg activation at fertilization in all species thus far examined is caused by some form of transient increase in the cytoplasmic free Ca(2+) concentration. What has not been clear, however, is precisely how the sperm triggers the large changes in Ca(2+) observed within the egg cytoplasm. Here, we review the studies indicating that the fertilizing sperm stimulates a cytosolic Ca(2+) increase in the egg specifically by delivering a soluble factor that diffuses into the cytosolic space of the egg upon gamete membrane fusion. Evidence is primarily considered in species of eggs where the sperm has been shown to elicit a cytosolic Ca(2+) increase by initiating Ca(2+) release from intracellular Ca(2+) stores. We suggest that our best understanding of these signaling events is in mammals, where the sperm triggers a prolonged series of intracellular Ca(2+) oscillations. The strongest empirical studies to date suggest that mammalian sperm-triggered Ca(2+) oscillations are caused by the introduction of a sperm-specific protein, called phospholipase C-zeta (PLCζ) that generates inositol trisphosphate within the egg. We will discuss the role and mechanism of action of PLCζ in detail at a molecular and cellular level. We will also consider some of the evidence that a soluble sperm protein might be involved in egg activation in nonmammalian species.

  12. Genome activation by raspberry bushy dwarf virus coat protein.

    Science.gov (United States)

    Macfarlane, Stuart A; McGavin, Wendy J

    2009-03-01

    Two sets of infectious cDNA clones of raspberry bushy dwarf virus (RBDV) have been constructed, enabling either the synthesis of infectious RNA transcripts or the delivery of infectious binary plasmid DNA by infiltration of Agrobacterium tumefaciens. In whole plants and in protoplasts, inoculation of RBDV RNA1 and RNA2 transcripts led to a low level of infection, which was greatly increased by the addition of RNA3, a subgenomic RNA coding for the RBDV coat protein (CP). Agroinfiltration of RNA1 and RNA2 constructs did not produce a detectable infection but, again, inclusion of a construct encoding the CP led to high levels of infection. Thus, RBDV replication is greatly stimulated by the presence of the CP, a mechanism that also operates with ilarviruses and alfalfa mosaic virus, where it is referred to as genome activation. Mutation to remove amino acids from the N terminus of the CP showed that the first 15 RBDV CP residues are not required for genome activation. Other experiments, in which overlapping regions at the CP N terminus were fused to the monomeric red fluorescent protein, showed that sequences downstream of the first 48 aa are not absolutely required for genome activation. PMID:19218221

  13. Hypertension and Atrial Fibrillation: Any Change with the New Anticoagulants.

    Science.gov (United States)

    Ghiadoni, Lorenzo; Taddei, Stefano; Virdis, Agostino

    2014-01-01

    Hypertension and atrial fibrillation are the most common cardiovascular risk factors and clinically significant arrhythmia, respectively. These conditions frequently coexist and their prevalence increases rapidly with aging. Despite several different risk factors and clinical conditions predisposing to hypertension for its high prevalence in the population is still the main risk factor for the development of atrial fibrillation. Several pathophysiologic mechanisms (such as structural changes at the level of left ventricle and or atrium, neurohormonal activation, arterial stiffness, etc.) can contribute to the onset of atrial fibrillation. Some antihypertensive treatments have been shown to contribute to reduce the risk of new-onset atrial fibrillation. Atrial fibrillation is a major risk factor for stroke, which is further increased in the presence of hypertension. For this reason, hypertension is included as a major risk factor in the available models for the risk stratification and the prevention of thromboembolism in patients with atrial fibrillation. In this article we will review the relationship between atrial fibrillation and hypertension, looking at the possible specific indications of the antithrombotic treatment with new classes of anticoagulants in the prevention of thromboembolic events in hypertensive patients with atrial fibrillation.

  14. A protein tyrosine phosphatase-like protein from baculovirus has RNA 5'-triphosphatase and diphosphatase activities.

    Science.gov (United States)

    Takagi, T; Taylor, G S; Kusakabe, T; Charbonneau, H; Buratowski, S

    1998-08-18

    The superfamily of protein tyrosine phosphatases (PTPs) includes at least one enzyme with an RNA substrate. We recently showed that the RNA triphosphatase domain of the Caenorhabditis elegans mRNA capping enzyme is related to the PTP enzyme family by sequence similarity and mechanism. The PTP most similar in sequence to the capping enzyme triphosphatase is BVP, a dual-specificity PTP encoded by the Autographa californica nuclear polyhedrosis virus. Although BVP previously has been shown to have modest tyrosine and serine/threonine phosphatase activity, we find that it is much more potent as an RNA 5'-phosphatase. BVP sequentially removes gamma and beta phosphates from the 5' end of triphosphate-terminated RNA, leaving a 5'-monophosphate end. The activity was specific for polynucleotides; nucleotide triphosphates were not hydrolyzed. A mutant protein in which the active site cysteine was replaced with serine was inactive. Three other dual-specificity PTPs (VH1, VHR, and Cdc14) did not exhibit detectable RNA phosphatase activity. Therefore, capping enzyme and BVP are members of a distinct PTP-like subfamily that can remove phosphates from RNA. PMID:9707557

  15. Immersion freezing of ice nucleation active protein complexes

    Science.gov (United States)

    Hartmann, S.; Augustin, S.; Clauss, T.; Wex, H.; Šantl-Temkiv, T.; Voigtländer, J.; Niedermeier, D.; Stratmann, F.

    2013-06-01

    Utilising the Leipzig Aerosol Cloud Interaction Simulator (LACIS), the immersion freezing behaviour of droplet ensembles containing monodisperse particles, generated from a Snomax™ solution/suspension, was investigated. Thereto ice fractions were measured in the temperature range between -5 °C to -38 °C. Snomax™ is an industrial product applied for artificial snow production and contains Pseudomonas syringae} bacteria which have long been used as model organism for atmospheric relevant ice nucleation active (INA) bacteria. The ice nucleation activity of such bacteria is controlled by INA protein complexes in their outer membrane. In our experiments, ice fractions increased steeply in the temperature range from about -6 °C to about -10 °C and then levelled off at ice fractions smaller than one. The plateau implies that not all examined droplets contained an INA protein complex. Assuming the INA protein complexes to be Poisson distributed over the investigated droplet populations, we developed the CHESS model (stoCHastic modEl of similar and poiSSon distributed ice nuclei) which allows for the calculation of ice fractions as function of temperature and time for a given nucleation rate. Matching calculated and measured ice fractions, we determined and parameterised the nucleation rate of INA protein complexes exhibiting class III ice nucleation behaviour. Utilising the CHESS model, together with the determined nucleation rate, we compared predictions from the model to experimental data from the literature and found good agreement. We found that (a) the heterogeneous ice nucleation rate expression quantifying the ice nucleation behaviour of the INA protein complex is capable of describing the ice nucleation behaviour observed in various experiments for both, Snomax™ and P. syringae bacteria, (b) the ice nucleation rate, and its temperature dependence, seem to be very similar regardless of whether the INA protein complexes inducing ice nucleation are attached

  16. Immersion freezing of ice nucleation active protein complexes

    Directory of Open Access Journals (Sweden)

    S. Hartmann

    2013-06-01

    Full Text Available Utilising the Leipzig Aerosol Cloud Interaction Simulator (LACIS, the immersion freezing behaviour of droplet ensembles containing monodisperse particles, generated from a Snomax™ solution/suspension, was investigated. Thereto ice fractions were measured in the temperature range between −5 °C to −38 °C. Snomax™ is an industrial product applied for artificial snow production and contains Pseudomonas syringae} bacteria which have long been used as model organism for atmospheric relevant ice nucleation active (INA bacteria. The ice nucleation activity of such bacteria is controlled by INA protein complexes in their outer membrane. In our experiments, ice fractions increased steeply in the temperature range from about −6 °C to about −10 °C and then levelled off at ice fractions smaller than one. The plateau implies that not all examined droplets contained an INA protein complex. Assuming the INA protein complexes to be Poisson distributed over the investigated droplet populations, we developed the CHESS model (stoCHastic modEl of similar and poiSSon distributed ice nuclei which allows for the calculation of ice fractions as function of temperature and time for a given nucleation rate. Matching calculated and measured ice fractions, we determined and parameterised the nucleation rate of INA protein complexes exhibiting class III ice nucleation behaviour. Utilising the CHESS model, together with the determined nucleation rate, we compared predictions from the model to experimental data from the literature and found good agreement. We found that (a the heterogeneous ice nucleation rate expression quantifying the ice nucleation behaviour of the INA protein complex is capable of describing the ice nucleation behaviour observed in various experiments for both, Snomax™ and P. syringae bacteria, (b the ice nucleation rate, and its temperature dependence, seem to be very similar regardless of whether the INA protein complexes inducing ice

  17. Spontaneous iliopsoas muscle haematoma as a complication of anticoagulation in acute cerebral venous thrombosis: to stop or not to stop (the anticoagulation)?

    Science.gov (United States)

    Fernandes, Carina; Pereira, Pedro; Rodrigues, Miguel

    2015-01-01

    Spontaneous iliopsoas muscle haematoma is an infrequent complication of anticoagulation, potentially causing neurological dysfunction through compression of the femoral nerve or lumbar plexus. The authors report the case of a puerperal woman admitted for an extensive cerebral venous thrombosis. Anticoagulation was started, with clinical improvement. The patient later reported low back pain irradiating to the right thigh and developed neurological impairment consistent with lumbar plexus dysfunction. A pelvic CT scan revealed a right iliopsoas muscle haematoma. Considering the risk of anticoagulation suspension, a conservative approach was chosen, with maintenance of anticoagulation. Clinical and functional improvement occurred, with mild right hip and knee flexion paresis as sequelae. Anticoagulation complications are challenging, especially when interruption of anticoagulation may threaten vital and functional outcomes. Therefore, a careful evaluation is essential, since no clinical guidelines are available. In this case, continuing anticoagulation provided a good functional outcome. PMID:25750219

  18. Redox regulation of the AMP-activated protein kinase.

    Directory of Open Access Journals (Sweden)

    Yingying Han

    Full Text Available Redox state is a critical determinant of cell function, and any major imbalances can cause severe damage or death.The aim of this study is to determine if AMP-activated protein kinase (AMPK, a cellular energy sensor, is activated by oxidants generated by Berberine in endothelial cells (EC.Bovine aortic endothelial cells (BAEC were exposed to Berberine. AMPK activity and reactive oxygen species were monitored after the incubation.In BAEC, Berberine caused a dose- and time-dependent increase in the phosphorylation of AMPK at Thr172 and acetyl CoA carboxylase (ACC at Ser79, a well characterized downstream target of AMPK. Concomitantly, Berberine increased peroxynitrite, a potent oxidant formed by simultaneous generation of superoxide and nitric oxide. Pre-incubation of BAEC with anti-oxidants markedly attenuated Berberine-enhanced phosphorylation of both AMPK and ACC. Consistently, adenoviral expression of superoxide dismutase and pretreatment of L-N(G-Nitroarginine methyl ester (L-NAME; a non-selective NOS inhibitor blunted Berberine-induced phosphorylation of AMPK. Furthermore, mitochondria-targeted tempol (mito-tempol pretreatment or expression of uncoupling protein attenuated AMPK activation caused by Berberine. Depletion of mitochondria abolished the effects of Berberine on AMPK in EC. Finally, Berberine significantly increased the phosphorylation of LKB1 at Ser307 and gene silencing of LKB1 attenuated Berberine-enhanced AMPK Thr172 phosphorylation in BAEC.Our results suggest that mitochondria-derived superoxide anions and peroxynitrite are required for Berberine-induced AMPK activation in endothelial cells.

  19. Protein composition of catalytically active human telomerase from immortal cells

    DEFF Research Database (Denmark)

    Cohen, Scott B; Graham, Mark E; Lovrecz, George O;

    2007-01-01

    Telomerase is a ribonucleoprotein enzyme complex that adds 5'-TTAGGG-3' repeats onto the ends of human chromosomes, providing a telomere maintenance mechanism for approximately 90% of human cancers. We have purified human telomerase approximately 10(8)-fold, with the final elution dependent on the...... enzyme's ability to catalyze nucleotide addition onto a DNA oligonucleotide of telomeric sequence, thereby providing specificity for catalytically active telomerase. Mass spectrometric sequencing of the protein components and molecular size determination indicated an enzyme composition of two molecules...... each of telomerase reverse transcriptase, telomerase RNA, and dyskerin....

  20. The Metastasis-associated Proteins 1 and 2 Form Distinct Protein Complexes with Histone Deacetylase Activity

    Institute of Scientific and Technical Information of China (English)

    Ya-LiYao; Wcn-MingYang

    2005-01-01

    The metastasis-associated protein MTA1 has been shown to express differentially to high levels in metastatic cells. MTA2, which is homologous to MTA1, is a component of the NURD ATP-dependcnt chromatin remodeling and histone deacetylase complex. Here we report evidence that although both human MTA1 and MTA2 repress transcription specifically, are located in the nucleus, and contain associated histone deacetylase activity, they exist in two biochemically distinct protein complexes and may perform different functions pertaining to tumor metastasis. Specifically, both MTA1 and MTA2 complexes exert histone deacetylase activity. However, the MTA1 complex contained HDAC1/2, RbAp46/48, and MBD3, but not Sin3 or Mi2, two important components of the MTA2 complex. Moreover, the MTA2 complex is similar to the HDAC1 complex, suggesting a housekeeping role of the MTA2 complex. The MTA1 complex could be further separated, resulting in acore MTA1-HDAC complex, showing that the histone deacetylase activity and transcriptional repression activity were integral properties of the MTA1 complex. Finally, MTA1, unlike MTA2, did not interact with the pleotropic transcription factor YY1 or the immunophilin FKBP25. We suggest that MTA1 associates with adifferent set of transcription factors from MTA2 and that this property may contribute to the metastatic potential of cells overexpressing MTA1. We also report the finding of human MTA3, which is highly homologous toboth MTA1 and MTA2. However, MTA3 does not repress transcription to a significant level and appears to have a diffused pattern of subcellular localization, suggesting a biological role distinct from that of the other two MTA proteins.

  1. Parenteral anticoagulants: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines.

    Science.gov (United States)

    Garcia, David A; Baglin, Trevor P; Weitz, Jeffrey I; Samama, Meyer Michel

    2012-02-01

    This article describes the pharmacology of approved parenteral anticoagulants. These include the indirect anticoagulants, unfractionated heparin (UFH), low-molecular-weight heparins (LMWHs), fondaparinux, and danaparoid, as well as the direct thrombin inhibitors hirudin, bivalirudin, and argatroban. UFH is a heterogeneous mixture of glycosaminoglycans that bind to antithrombin via a unique pentasaccharide sequence and catalyze the inactivation of thrombin, factor Xa, and other clotting enzymes. Heparin also binds to cells and plasma proteins other than antithrombin causing unpredictable pharmacokinetic and pharmacodynamic properties and triggering nonhemorrhagic side effects, such as heparin-induced thrombocytopenia (HIT) and osteoporosis. LMWHs have greater inhibitory activity against factor Xa than thrombin and exhibit less binding to cells and plasma proteins than heparin. Consequently, LMWH preparations have more predictable pharmacokinetic and pharmacodynamic properties, have a longer half-life than heparin, and are associated with a lower risk of nonhemorrhagic side effects. LMWHs can be administered once daily or bid by subcutaneous injection, without coagulation monitoring. Based on their greater convenience, LMWHs have replaced UFH for many clinical indications. Fondaparinux, a synthetic pentasaccharide, catalyzes the inhibition of factor Xa, but not thrombin, in an antithrombin-dependent fashion. Fondaparinux binds only to antithrombin. Therefore, fondaparinux-associated HIT or osteoporosis is unlikely to occur. Fondaparinux exhibits complete bioavailability when administered subcutaneously, has a longer half-life than LMWHs, and is given once daily by subcutaneous injection in fixed doses, without coagulation monitoring. Three additional parenteral direct thrombin inhibitors and danaparoid are approved as alternatives to heparin in patients with HIT. PMID:22315264

  2. Monomeric G protein-coupled receptor rhodopsin in solution activates its G protein transducin at the diffusion limit

    OpenAIRE

    Ernst, Oliver P.; Gramse, Verena; Kolbe, Michael; Hofmann, Klaus Peter; Heck, Martin

    2007-01-01

    G protein-coupled receptors mediate biological signals by stimulating nucleotide exchange in heterotrimeric G proteins (Gαβγ). Receptor dimers have been proposed as the functional unit responsible for catalytic interaction with Gαβγ. To investigate whether a G protein-coupled receptor monomer can activate Gαβγ, we used the retinal photoreceptor rhodopsin and its cognate G protein transducin (Gt) to determine the stoichiometry of rhodopsin/Gt binding and the rate of catalyzed nucleotide exchan...

  3. Novel oral anticoagulants in secondary prevention of stroke.

    Science.gov (United States)

    Diener, H C; Easton, J D; Hankey, G J; Hart, R G

    2013-06-01

    In patients with atrial fibrillation (AF) oral anticoagulation with vitamin-K antagonists (warfarin, phenprocoumon) is effective both for primary and secondary stroke prevention yielding a 60-70% relative reduction in stroke risk compared with placebo, as well as a mortality reduction of 26 percent. Vitamin-K antagonists have a number of well documented shortcomings. Recently the results of randomised trials for three new oral anticoagulants that do not exhibit the limitations of vitamin-K antagonists have been published. These include direct factor Xa inhibitors (rivaroxaban and apixaban) and a direct thrombin inhibitor (dabigatran). The studies (RE-LY, ROCKET-AF, ARISTOTLE, AVERROES) provide promising results for the new agents, including higher efficacy and a significantly lower incidence of intracranial bleeds compared with warfarin or aspirin. The new drugs show similar results in secondary as well as in primary stroke prevention in patients with AF. Apixaban was demonstrated to be clearly superior to aspirin and had the same rate of major bleeding complications. Meta-analyses show that the novel anticoagulants are superior to warfarin for the reduction of stroke, major bleeding and intracranial bleeds. New anticoagulants add to the therapeutic options for patients with AF, and offer a number of advantages over warfarin, for both the clinician and patient, including a favorable bleeding profile and convenience of use. Aspirin is no longer an option in secondary stroke prevention in patients with atrial fibrillation. Consideration of these new anticoagulants will improve clinical decision making. PMID:23953901

  4. Novel oral anticoagulants in secondary prevention of stroke.

    Science.gov (United States)

    Diener, H C; Easton, J D; Hankey, G J; Hart, R G

    2013-06-01

    In patients with atrial fibrillation (AF) oral anticoagulation with vitamin-K antagonists (warfarin, phenprocoumon) is effective both for primary and secondary stroke prevention yielding a 60-70% relative reduction in stroke risk compared with placebo, as well as a mortality reduction of 26 percent. Vitamin-K antagonists have a number of well documented shortcomings. Recently the results of randomised trials for three new oral anticoagulants that do not exhibit the limitations of vitamin-K antagonists have been published. These include direct factor Xa inhibitors (rivaroxaban and apixaban) and a direct thrombin inhibitor (dabigatran). The studies (RE-LY, ROCKET-AF, ARISTOTLE, AVERROES) provide promising results for the new agents, including higher efficacy and a significantly lower incidence of intracranial bleeds compared with warfarin or aspirin. The new drugs show similar results in secondary as well as in primary stroke prevention in patients with AF. Apixaban was demonstrated to be clearly superior to aspirin and had the same rate of major bleeding complications. Meta-analyses show that the novel anticoagulants are superior to warfarin for the reduction of stroke, major bleeding and intracranial bleeds. New anticoagulants add to the therapeutic options for patients with AF, and offer a number of advantages over warfarin, for both the clinician and patient, including a favorable bleeding profile and convenience of use. Aspirin is no longer an option in secondary stroke prevention in patients with atrial fibrillation. Consideration of these new anticoagulants will improve clinical decision making.

  5. Anticoagulant rodenticide poisoning in animals of Apulia and Basilicata, Italy.

    Science.gov (United States)

    Muscarella, Marilena; Armentano, Antonio; Iammarino, Marco; Palermo, Carmen; Amorena, Michele

    2016-06-30

    This study evaluates the presence of anticoagulant rodenticides in animals with a diagnosis of suspected poisoning and in bait samples. The survey was carried out from 2010 to 2012, in 2 regions of South Italy (Puglia and Basilicata) on 300 organs of animals and 90 suspected bait samples. The qualitative and quantitative analyses were conducted using an analytical method based on high‑performance liquid chromatography (HPLC) with fluorimetric detection (FLD) for the simultaneous determination of 8 anticoagulant rodenticides (bromadiolone, brodifacoum, coumachlor, coumafuryl, coumatetralyl, difenacoum, flocoumafen, and warfarin). The presence of anticoagulant rodenticides was detected in 33 organs of animals (11% of the total) and 6 bait samples (7% of the total). The most commonly detected compound was coumachlor (47% of 39 positive samples) followed by bromadiolone (24%), and brodifacoum (11%). The species mostly involved in anticoagulant rodenticide poisoning were dogs and cats. This study emphasizes the relevance of the determinations of anticoagulant rodenticides in cases of suspected poisoning in veterinary practice. PMID:27393877

  6. Thermally activated charge transport in microbial protein nanowires.

    Science.gov (United States)

    Lampa-Pastirk, Sanela; Veazey, Joshua P; Walsh, Kathleen A; Feliciano, Gustavo T; Steidl, Rebecca J; Tessmer, Stuart H; Reguera, Gemma

    2016-01-01

    The bacterium Geobacter sulfurreducens requires the expression of conductive protein filaments or pili to respire extracellular electron acceptors such as iron oxides and uranium and to wire electroactive biofilms, but the contribution of the protein fiber to charge transport has remained elusive. Here we demonstrate efficient long-range charge transport along individual pili purified free of metal and redox organic cofactors at rates high enough to satisfy the respiratory rates of the cell. Carrier characteristics were within the orders reported for organic semiconductors (mobility) and inorganic nanowires (concentration), and resistivity was within the lower ranges reported for moderately doped silicon nanowires. However, the pilus conductance and the carrier mobility decreased when one of the tyrosines of the predicted axial multistep hopping path was replaced with an alanine. Furthermore, low temperature scanning tunneling microscopy demonstrated the thermal dependence of the differential conductance at the low voltages that operate in biological systems. The results thus provide evidence for thermally activated multistep hopping as the mechanism that allows Geobacter pili to function as protein nanowires between the cell and extracellular electron acceptors. PMID:27009596

  7. Physical activity and high-sensitivity C-reactive protein.

    Science.gov (United States)

    Plaisance, Eric P; Grandjean, Peter W

    2006-01-01

    Cardiovascular disease (CVD) remains one of the leading causes of death and disability in developed countries around the world despite the documented success of lifestyle and pharmacological interventions. This illustrates the multifactorial nature of atherosclerosis and the use of novel inflammatory markers as an adjunct to risk factor reduction strategies. As evidence continues to accumulate that inflammation is involved in all stages of the development and progression of atherosclerosis, markers of inflammation such as high-sensitivity C-reactive protein (CRP) may provide additional information regarding the biological status of the atherosclerotic lesion. Recent investigations suggest that physical activity reduces CRP levels. Higher levels of physical activity and cardiorespiratory fitness are consistently associated with 6-35% lower CRP levels. Longitudinal training studies that have demonstrated reductions in CRP concentrations range from 16% to 41%, an effect that may be independent of baseline levels of CRP, body composition or weight loss. The average change in CRP associated with physical activity appears to be at least as good, if not better, than currently prescribed pharmacological interventions in similar populations. The primary purpose of this review will be to present evidence from both cross-sectional and longitudinal investigations that physical activity lowers CRP levels in a dose-response manner. Finally, this review will examine factors such as body composition, sex, blood sample timing, diet and smoking, which may influence the CRP response to physical activity. PMID:16646631

  8. TALE proteins bind to both active and inactive chromatin.

    Science.gov (United States)

    Scott, James N F; Kupinski, Adam P; Kirkham, Christopher M; Tuma, Roman; Boyes, Joan

    2014-02-15

    TALE (transcription activator-like effector) proteins can be tailored to bind to any DNA sequence of choice and thus are of immense utility for genome editing and the specific delivery of transcription activators. However, to perform these functions, they need to occupy their sites in chromatin. In the present study, we have systematically assessed TALE binding to chromatin substrates and find that in vitro TALEs bind to their target site on nucleosomes at the more accessible entry/exit sites, but not at the nucleosome dyad. We show further that in vivo TALEs bind to transcriptionally repressed chromatin and that transcription increases binding by only 2-fold. These data therefore imply that TALEs are likely to bind to their target in vivo even at inactive loci.

  9. Gene activation by triplex-forming oligonucleotide coupled to the activating domain of protein VP16.

    OpenAIRE

    Kuznetsova, S.; Ait-Si-Ali, S; Nagibneva, I; Troalen, F; Le Villain, J P; Harel-Bellan, A; Svinarchuk, F

    1999-01-01

    Triplex-forming oligonucleotides (TFOs) are generally designed to inhibit transcription or DNA replication but can be used for more diverse purposes. Here we have designed a chimera peptide-TFO able to activate transcription from a target gene. The designed hybrid molecule contains a triplex-forming sequence, linked through a phosphoroamidate bond to several minimal transcriptional activation domains derived from Herpes simplex virus protein 16 (VP16). We show here that this TFO-peptide chime...

  10. Antistaphylococcal activity of bacteriophage derived chimeric protein P128

    Directory of Open Access Journals (Sweden)

    Vipra Aradhana A

    2012-03-01

    Full Text Available Abstract Background Bacterial drug resistance is one of the most significant challenges to human health today. In particular, effective antibacterial agents against methicillin-resistant Staphylococcus aureus (MRSA are urgently needed. A causal relationship between nasal commensal S. aureus and infection has been reported. Accordingly, elimination of nasal S. aureus reduces the risk of infection. Enzymes that degrade bacterial cell walls show promise as antibacterial agents. Bacteriophage-encoded bacterial cell wall-degrading enzymes exhibit intrinsic bactericidal activity. P128 is a chimeric protein that combines the lethal activity of the phage tail-associated muralytic enzyme of Phage K and the staphylococcal cell wall targeting-domain (SH3b of lysostaphin. Here we report results of in vitro studies evaluating the susceptibility of staphylococcal strains to this novel protein. Results Using the broth microdilution method adapted for lysostaphin, we found that P128 is effective against S. aureus clinical strains including MRSA, methicillin-sensitive S. aureus (MSSA, and a mupirocin-resistant S. aureus. Minimum bactericidal concentrations and minimum inhibitory concentrations of P128 (1-64 μg/mL were similar across the 32 S. aureus strains tested, demonstrating its bactericidal nature. In time-kill assays, P128 reduced colony-forming units by 99.99% within 1 h and inhibited growth up to 24 h. In an assay simulating topical application of P128 to skin or other biological surfaces, P128 hydrogel was efficacious when layered on cells seeded on solid media. P128 hydrogel was lethal to Staphylococci recovered from nares of healthy people and treated without any processing or culturing steps, indicating its in situ efficacy. This methodology used for in vitro assessment of P128 as an agent for eradicating nasal carriage is unique. Conclusions The novel chimeric protein P128 is a staphylococcal cell wall-degrading enzyme under development for

  11. Adherence to oral anticoagulant therapy in secondary stroke prevention – impact of the novel oral anticoagulants

    Directory of Open Access Journals (Sweden)

    Luger S

    2015-11-01

    Full Text Available Sebastian Luger,1 Carina Hohmann,2 Daniela Niemann,1 Peter Kraft,3 Ignaz Gunreben,3 Tobias Neumann-Haefelin,2 Christoph Kleinschnitz,3 Helmuth Steinmetz,1 Christian Foerch,1 Waltraud Pfeilschifter1 1Department of Neurology, University Hospital Frankfurt, Frankfurt am Main, 2Department of Neurology, Klinikum Fulda gAG, Fulda, 3Department of Neurology, University Hospital Würzburg, Würzburg, Germany Background: Oral anticoagulant therapy (OAT potently prevents strokes in patients with atrial fibrillation. Vitamin K antagonists (VKA have been the standard of care for long-term OAT for decades, but non-VKA oral anticoagulants (NOAC have recently been approved for this indication, and raised many questions, among them their influence on medication adherence. We assessed adherence to VKA and NOAC in secondary stroke prevention. Methods: All patients treated from October 2011 to September 2012 for ischemic stroke or transient ischemic attack with a subsequent indication for OAT, at three academic hospitals were entered into a prospective registry, and baseline data and antithrombotic treatment at discharge were recorded. At the 1-year follow-up, we assessed the adherence to different OAT strategies and patients’ adherence to their respective OAT. We noted OAT changes, reasons to change treatment, and factors that influence persistence to the prescribed OAT. Results: In patients discharged on OAT, we achieved a fatality corrected response rate of 73.3% (n=209. A total of 92% of these patients received OAT at the 1-year follow-up. We observed good adherence to both VKA and NOAC (VKA, 80.9%; NOAC, 74.8%; P=0.243 with a statistically nonsignificant tendency toward a weaker adherence to dabigatran. Disability at 1-year follow-up was an independent predictor of lower adherence to any OAT after multivariate analysis, whereas the choice of OAT did not have a relevant influence. Conclusion: One-year adherence to OAT after stroke is strong (>90% and patients

  12. Protein phosphatase-1 activates CDK9 by dephosphorylating Ser175.

    Directory of Open Access Journals (Sweden)

    Tatiana Ammosova

    Full Text Available The cyclin-dependent kinase CDK9/cyclin T1 induces HIV-1 transcription by phosphorylating the carboxyterminal domain (CTD of RNA polymerase II (RNAPII. CDK9 activity is regulated by protein phosphatase-1 (PP1 which was previously shown to dephosphorylate CDK9 Thr186. Here, we analyzed the effect of PP1 on RNAPII phosphorylation and CDK9 activity. The selective inhibition of PP1 by okadaic acid and by NIPP1 inhibited phosphorylation of RNAPII CTD in vitro and in vivo. Expression of the central domain of NIPP1 in cultured cells inhibited the enzymatic activity of CDK9 suggesting its activation by PP1. Comparison of dephosphorylation of CDK9 phosphorylated by ((32P in vivo and dephosphorylation of CDK9's Thr186 analyzed by Thr186 phospho-specific antibodies, indicated that a residue other than Thr186 might be dephosphorylated by PP1. Analysis of dephosphorylation of phosphorylated peptides derived from CDK9's T-loop suggested that PP1 dephosphorylates CDK9 Ser175. In cultured cells, CDK9 was found to be phosphorylated on Ser175 as determined by combination of Hunter 2D peptide mapping and LC-MS analysis. CDK9 S175A mutant was active and S175D--inactive, and dephosphorylation of CDK9's Ser175 upregulated HIV-1 transcription in PP1-dependent manner. Collectively, our results point to CDK9 Ser175 as novel PP1-regulatory site which dephosphorylation upregulates CDK9 activity and contribute to the activation of HIV-1 transcription.

  13. Exercise in rats does not alter hypothalamic AMP-activated protein kinase activity

    DEFF Research Database (Denmark)

    Andersson, Ulrika; Treebak, Jonas Thue; Nielsen, Jakob Nis;

    2005-01-01

    Recent studies have demonstrated that AMP-activated protein kinase (AMPK) in the hypothalamus is involved in the regulation of food intake. Because exercise is known to influence appetite and cause substrate depletion, it may also influence AMPK in the hypothalamus. Male rats that either rested...

  14. Osmotic cell shrinkage activates ezrin/radixin/moesin (ERM) proteins : activation mechanisms and physiological implications

    NARCIS (Netherlands)

    Rasmussen, M.; Alexander, R.T.; Darborg, B.V.; Mobjerg, N.; Hoffmann, E.K.; Kapus, A.; Pedersen, S.F.

    2008-01-01

    Hyperosmotic shrinkage induces multiple cellular responses, including activation of volume-regulatory ion transport, cytoskeletal reorganization, and cell death. Here we investigated the possible roles of ezrin/radixin/moesin (ERM) proteins in these events. Osmotic shrinkage of Ehrlich Lettre ascite

  15. Protein kinase C-dependent activation of P44/42 mitogen-activated protein kinase and heat shock protein 70 in signal transduction during hepatocyte ischemic preconditioning

    Institute of Scientific and Technical Information of China (English)

    Yi Gao; Yu-Qiang Shan; Ming-Xin Pan; Yu Wang; Li-Jun Tang; Hao Li; Zhi Zhang

    2004-01-01

    AIM: To investigate the significance of protein kinase C (PKC), P44/42 mitogen-activated protein kinase (MAPKs) and heat shock protein (HSP)70 signal transduction during hepatocyte ischemic preconditioning.METHODS: In this study we used an in vitro ischemic preconditioning (IP) model for hepatocytes and an in vivo model for rat liver to investigate the significance of protein kinase C (PKC), P44/42 mitogen-activated protein kinase (P44/42 MAPKs) and heat shock protein 70 (HSP70) signal transduction in IP. Through a normal liver cell hypoxic preconditioning (HP) model in which cultured normal liver cells were subjected to 3 cycles of 5 min of incubation under hypoxic conditions followed by 5 min of reoxygenation and subsequently exposed to hypoxia and reoxygenation for 6 h and 9 h respectively. PKC inhibitor, activator and MEK inhibitor were utilized to analyze the phosphorylation of PKC, the expression of P44/42 MAPKs and HSP70.Viability and cellular ultrastructure were also observed. By using rat liver as an in vivo model of liver preconditioning (3 cycles of 10-min occlusion and 10-min reperfusion),in vivo phosphorylation of PKC and P44/42MAPKs, HSP70 expression were further analyzed. AST/ALT concentration,cellular structure and ultrastruture were also observed.All the data were statistically analyzed.RESULTS: Similar results were obtained in both in vivo and in vitro IP models. Compared with the control without IP (or HP), the phosphorylation of PKC and P44/42 MAPKs and the expression of HSP70 were obviously increased in IP (or HP) treated model in which cytoprotection could be found. The effects of preconditioning were mimicked by stimulating PKC with 4β phorobol-12-myristate13-acetate (PMA). Conversely, inhibiting PKC with chelerythrine abolished the protection given by preconditioning. PD98059,inhibitor of MEK (the upstream kinase of P44/42MAPKs),also reverted the cytoprotection exerted by preconditioning.CONCLUSION: The results demonstrate that

  16. NEW ORAL ANTICOAGULANTS IN THE THERAPY OF ANTIPHOSPHOLIPID SYNDROME

    Directory of Open Access Journals (Sweden)

    M. A. Satybaldyeva

    2016-01-01

    Full Text Available The vitamin K antagonist warfarin is an essential medicine from a group of anticoagulants, which is used to treat antiphospholipid syndrome (APS. However, it has a number of disadvantages especially in patients who need longterm and frequently lifetime prevention of thromboses. New oral anticoagulants, such as dabigatran etexilate (Pradaxa®, rivaroxaban (Xarelto®, apixaban (Eliquis and others, have been recently synthesized. Unlike warfarin, they are administered at fixed doses, require neither routine monitoring nor diet, and interact with drugs only in small amounts. The new oral anticoagulants have been approved for certain indications, but the data of performed trials are inapplicable to patients with APS. These medicines are expected to improve quality of life in patients with this condition. 

  17. [Heparin induced thrombocytopenia and anticoagulation in renal replacemant therapy].

    Science.gov (United States)

    Steinfeldt, Thorsten; Rolfes, Caroline

    2008-04-01

    The decision for an anticoagulant for renal replacement therapy (RRT) in patients with acute renal failure and heparin-induced thrombocytopenia (HIT) has to be made carefully. Based on results from the literature argatroban is favoured in patients without hepatic dysfunction, referring to its short halftime and easy feasable monitoring. In the case of coexsisting hepatic disorder, danaparoid provides a safe alternative therapy. However, long halftime and the difficult elimination of the substance are unfavourable. Lepirudin represents another possible anticoagulant therapy. Bleeding complications and monitoring of the ecarin clotting time imposes limitations. Experiences with bivalirudin, fondaparinux and prostaglandines are limited and future trials will have to determine the significance of their application in RRT in HIT patients. Furthermore it has to be proven whether the combination of alternative anticoagulants with citrate prolongates circuit halftime of CVVH.

  18. A pharmacologic overview of current and emerging anticoagulants.

    Science.gov (United States)

    Nutescu, Edith A; Shapiro, Nancy L; Chevalier, Aimee; Amin, Alpesh N

    2005-04-01

    For over 50 years, anticoagulant options for the treatment and prevention of thrombosis have been limited mainly to traditional agents such as unfractionated heparin and oral vitamin K antagonists such as warfarin. These traditional agents are fraught with limitations that complicate their clinical use. A variety of novel anticoagulants with improved pharmacologic and clinical profiles have recently been introduced or are in development, offering benefits over traditional therapies. Specifically, progress has been made in the development of low-molecular-weight heparins, factor Xa inhibitors, and direct thrombin inhibitors. Because of their convenience and ease of use, some of these novel compounds are competing with the traditional anticoagulants and are needed additions to the antithrombotic arsenal. PMID:15853173

  19. Advanced oxidation protein products induce monocyte chemoattractant protein-1 expression via p38 mitogen-activated protein kinase activation in rat vascular smooth muscle cells

    Institute of Scientific and Technical Information of China (English)

    PENG Kan-fu; WU Xiong-fei; ZHAO Hong-wen; SUN Yan

    2006-01-01

    Background Advanced oxidation protein products (AOPPs) are new uremic toxins reported by Witko-Sarsat in 1996, which are associated with the pathogenesis of atherosclerosis. However, the mechanisms by which AOPPs enhance atherosclerosis have not been fully understood. Monocyte chemoattractant protein-1 (MCP-1) is a chemokine which stimulates migration of monocytes and plays a critical role in the development of atherosclerosis. In this study, we investigated the effect of AOPPs on MCP-1 expression in cultured vascular smooth muscle cells (VSMCs).Methods VSMCs were cultured and then co-incubated with AOPP (200 μ mol/L, 400 μ mol/L) for different times with or without pretreatment with specific p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580. RT-PCR and Western blott were used to detect MCP-1 mRNA and protein expression at different time points after AOPP stimulation in rat smooth muscle cells. Western blot was used to detect the expression of phosphorylated p38 MAPK.Results Treatment of VSMC with AOPPs resulted in a significant increase of the expression of MCP- 1 mRNA and protein in time- and dose-dependent manner, and could activated p38 MAPK. Pretreatment of VSMCs with SB203580 resulted in a dose-dependent inhibition of AOPPs-induced MCP-1 mRNA and protein expression.Conclusions AOPPs can stimulate MCP-1 expression via p38 MAPK in VSMCs. This suggests that AOPPs might contribute to the formation of atherosclerosis through this proinflammatory effect.

  20. Effect of Crocus sativus L. (saffron) on coagulation and anticoagulation systems in healthy volunteers.

    Science.gov (United States)

    Ayatollahi, Hossein; Javan, Atefeh Ordoei; Khajedaluee, Mohammad; Shahroodian, Masood; Hosseinzadeh, Hossein

    2014-04-01

    Saffron showed some effects on blood coagulation and platelet aggregation in in vitro and in vivo studies. In a clinical trial with a limited number volunteers, saffron tablets influenced on bleeding time. In this study, the effect of saffron on plasma level of fibrinogen, factor VII (as coagulant agent), C and S protein (as anti-coagulant agent), PT and PTT in a larger sample size was evaluated. The study was a double-blind, placebo-controlled study consisting of 1 week treatment with 200 mg and 400 mg saffron tablets. Sixty healthy volunteers (age range 20-50 years) were selected for the study. The volunteers were divided into three groups of 20 each. Group 1 received placebo; Groups 2 and 3 received 200 mg and 400 mg saffron tablets, respectively, for 7 days (1 tablet per day). Before and after 7 days treatment and also 1 month after that, blood samples were taken. The plasma levels of fibrinogen, factor VII, C and S protein, PT and PTT were evaluated. Statistical analysis showed no difference between groups for any of evaluated factors. This study rejected any effect of saffron with dose of 200 and 400 mg for 1 week on coagulant and anticoagulant system.

  1. Evaluating the impact of new anticoagulants in the hospital setting

    Directory of Open Access Journals (Sweden)

    Braidy N

    2011-03-01

    Full Text Available The short-comings of current anticoagulants have led to the development of newer, albeit more expensive, oral alternatives.Objective: To explore the potential impact the new anticoagulants dabigatran and rivaroxaban in the local hospital setting, in terms of utilisation and subsequent costing.Method: A preliminary costing analysis was performed based on a prospective 2-week clinical audit (29th June - 13th July 2009. Data regarding current anticoagulation management were extracted from the medical files of patients admitted to Ryde Hospital. To model potential costing implications of using the newer agents, the reported incidence of VTE/stroke and bleeding events were obtained from key clinical trials.Results: Data were collected for 67 patients treated with either warfarin (n=46 or enoxaparin (n=21 for prophylaxis of VTE/stroke. At least two-thirds of all patients were deemed suitable candidates for the use of newer oral anticoagulants (by current therapy: warfarin: 65.2% (AF, 34.8% (VTE; enoxaparin: 100%, (VTE. The use of dabigatran in VTE/stroke prevention was found to be more cost-effective than warfarin and enoxaparin due to significantly lower costs of therapeutic monitoring and reduced administration costs. Rivaroxaban was more cost-effective than warfarin and enoxaparin for VTE/stroke prevention when supplier-rebates (33% were factored into costing.Conclusion: This study highlights the potential cost-effectiveness of newer anticoagulants, dabigatran and rivaroxaban, compared to warfarin and enoxaparin. These agents may offer economic advantages, as well as clinical benefits, in the hospital-based management of anticoagulated patients.

  2. Protein kinase A binds and activates heat shock factor 1.

    Directory of Open Access Journals (Sweden)

    Ayesha Murshid

    Full Text Available BACKGROUND: Many inducible transcription factors are regulated through batteries of posttranslational modifications that couple their activity to inducing stimuli. We have studied such regulation of Heat Shock Factor 1 (HSF1, a key protein in control of the heat shock response, and a participant in carcinogenisis, neurological health and aging. As the mechanisms involved in the intracellular regulation of HSF1 in good health and its dysregulation in disease are still incomplete we are investigating the role of posttranslational modifications in such regulation. METHODOLOGY/PRINCIPAL FINDINGS: In a proteomic study of HSF1 binding partners, we have discovered its association with the pleiotropic protein kinase A (PKA. HSF1 binds avidly to the catalytic subunit of PKA, (PKAcα and becomes phosphorylated on a novel serine phosphorylation site within its central regulatory domain (serine 320 or S320, both in vitro and in vivo. Intracellular PKAcα levels and phosphorylation of HSF1 at S320 were both required for HSF1 to be localized to the nucleus, bind to response elements in the promoter of an HSF1 target gene (hsp70.1 and activate hsp70.1 after stress. Reduction in PKAcα levels by small hairpin RNA led to HSF1 exclusion from the nucleus, its exodus from the hsp70.1 promoter and decreased hsp70.1 transcription. Likewise, null mutation of HSF1 at S320 by alanine substitution for serine led to an HSF1 species excluded from the nucleus and deficient in hsp70.1 activation. CONCLUSIONS: These findings of PKA regulation of HSF1 through S320 phosphorylation add to our knowledge of the signaling networks converging on this factor and may contribute to elucidating its complex roles in the stress response and understanding HSF1 dysregulation in disease.

  3. Sustained mitogen-activated protein kinase activation reprograms defense metabolism and phosphoprotein profile in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Ines eLassowskat

    2014-10-01

    Full Text Available Mitogen-activated protein kinases (MAPKs target a variety of protein substrates to regulate cellular signaling processes in eukaryotes. In plants, the number of identified MAPK substrates that control plant defense responses is still limited. Here, we generated transgenic Arabidopsis thaliana plants with an inducible system to simulate in vivo activation of two stress-activated MAPKs, MPK3 and MPK6. Metabolome analysis revealed that this artificial MPK3/6 activation (without any exposure to pathogens or other stresses is sufficient to drive the production of major defense-related metabolites, including various camalexin, indole glucosinolate and agmatine derivatives. An accompanying (phosphoproteome analysis led to detection of hundreds of potential phosphoproteins downstream of MPK3/6 activation. Besides known MAPK substrates, many candidates on this list possess typical MAPK-targeted phosphosites and in many cases, the corresponding phosphopeptides were detected by mass spectrometry. Notably, several of these putative phosphoproteins have been reported to be associated with the biosynthesis of antimicrobial defense substances (e.g. WRKY transcription factors and proteins encoded by the genes from the PEN pathway required for penetration resistance to filamentous pathogens. Thus, this work provides an inventory of candidate phosphoproteins, including putative direct MAPK substrates, for future analysis of MAPK-mediated defense control. (Proteomics data are available with the identifier PXD001252 via ProteomeXchange, http://proteomecentral.proteomexchange.org.

  4. A Variable Light Domain Fluorogen Activating Protein Homodimerizes To Activate Dimethylindole Red

    Energy Technology Data Exchange (ETDEWEB)

    Senutovitch, Nina; Stanfield, Robyn L.; Bhattacharyya, Shantanu; Rule, Gordon S.; Wilson, Ian A.; Armitage, Bruce A.; Waggoner, Alan S.; Berget, Peter B. (Scripps); (CM)

    2012-07-11

    Novel fluorescent tools such as green fluorescent protein analogues and fluorogen activating proteins (FAPs) are useful in biological imaging for tracking protein dynamics in real time with a low fluorescence background. FAPs are single-chain variable fragments (scFvs) selected from a yeast surface display library that produce fluorescence upon binding a specific dye or fluorogen that is normally not fluorescent when present in solution. FAPs generally consist of human immunoglobulin variable heavy (V{sub H}) and variable light (V{sub L}) domains covalently attached via a glycine- and serine-rich linker. Previously, we determined that the yeast surface clone, V{sub H}-V{sub L} M8, could bind and activate the fluorogen dimethylindole red (DIR) but that the fluorogen activation properties were localized to the M8V{sub L} domain. We report here that both nuclear magnetic resonance and X-ray diffraction methods indicate the M8V{sub L} forms noncovalent, antiparallel homodimers that are the fluorogen activating species. The M8V{sub L} homodimers activate DIR by restriction of internal rotation of the bound dye. These structural results, together with directed evolution experiments with both V{sub H}-V{sub L} M8 and M8V{sub L}, led us to rationally design tandem, covalent homodimers of M8V{sub L} domains joined by a flexible linker that have a high affinity for DIR and good quantum yields.

  5. Danthron activates AMP-activated protein kinase and regulates lipid and glucose metabolism in vitro

    Institute of Scientific and Technical Information of China (English)

    Rong ZHOU; Ling WANG; Xing XU; Jing CHEN; Li-hong HU; Li-li CHEN; Xu SHEN

    2013-01-01

    Aim:To discover the active compound on AMP-activated protein kinase (AMPK) activation and investigate the effects of the active compound 1,8-dihydroxyanthraquinone (danthron) from the traditional Chinese medicine rhubarb on AMPK-mediated lipid and glucose metabolism in vitro.Methods:HepG2 and C2C12 cells were used.Cell viability was determined using MTT assay.Real-time PCR was performed to measure the gene expression.Western blotting assay was applied to investigate the protein phosphorylation level.Enzymatic assay kits were used to detect the total cholesterol (TC),triglyceride (TG) and glucose contents.Results:Danthron (0.1,1,and 10 μmol/L) dose-dependently promoted the phosphorylation of AMPK and acetyl-CoA carboxylase (ACC)in both HepG2 and C2C12 cells.Meanwhile,danthron treatment significantly reduced the lipid synthesis related sterol regulatory element-binding protein 1c (SREBP1c) and fatty acid synthetase (FAS) gene expressions,and the TC and TG levels.In addition,danthron treatment efficiently increased glucose consumption.The actions of danthron on lipid and glucose metabolism were abolished or reversed by co-treatment with the AMPK inhibitor compound C.Conclusion:Danthron effectively reduces intracellular lipid contents and enhanced glucose consumption in vitro via activation of AMPK signaling pathway.

  6. Leishmania amazonensis: PKC-like protein kinase modulates the (Na++K+)ATPase activity.

    Science.gov (United States)

    Almeida-Amaral, Elmo Eduardo de; Caruso-Neves, Celso; Lara, Lucienne Silva; Pinheiro, Carla Mônica; Meyer-Fernandes, José Roberto

    2007-08-01

    The present study aimed to identify the presence of protein kinase C-like (PKC-like) in Leishmania amazonensis and to elucidate its possible role in the modulation of the (Na(+)+K(+))ATPase activity. Immunoblotting experiments using antibody against a consensus sequence (Ac 543-549) of rabbit protein kinase C (PKC) revealed the presence of a protein kinase of 80 kDa in L. amazonensis. Measurements of protein kinase activity showed the presence of both (Ca(2+)-dependent) and (Ca(2+)-independent) protein kinase activity in plasma membrane and cytosol. Phorbol ester (PMA) activation of the Ca(2+)-dependent protein kinase stimulated the (Na(+)+K(+))ATPase activity, while activation of the Ca(2+)-independent protein kinase was inhibitory. Both effects of protein kinase on the (Na(+)+K(+))ATPase of the plasma membrane were lower than that observed in intact cells. PMA induced the translocation of protein kinase from cytosol to plasma membrane, indicating that the maximal effect of protein kinase on the (Na(+)+K(+))ATPase activity depends on the synergistic action of protein kinases from both plasma membrane and cytosol. This is the first demonstration of a protein kinase activated by PMA in L. amazonensis and the first evidence for a possible role in the regulation of the (Na(+)+K(+))ATPase activity in this trypanosomatid. Modulation of the (Na(+)+K(+))ATPase by protein kinase in a trypanosomatid opens up new possibilities to understand the regulation of ion homeostasis in this parasite. PMID:17475255

  7. Regulatory Impact on Thrombosis Treatment, Prevention, and Anticoagulant Use.

    Science.gov (United States)

    Dannemiller, Robert; Ward, Tucker; Fanikos, John

    2016-10-01

    Thromboembolism afflicts millions of patients annually in the United States and is associated with a significant cost burden. Oral anticoagulants provide clinicians with options for management of these diseases and their use continues to grow. Accordingly, regulatory, legislative, and nonprofit organizations have set performance standards with the goal of improving patient outcomes, ensuring patient safety, and reducing costs. Recent efforts in quality improvement have introduced changes surrounding regulatory requirements, surveillance, litigation, and oversight that clinicians should be familiar with. This article summarizes key updates related to the management of anticoagulant therapy as it relates to thrombosis prevention and treatment. PMID:27637311

  8. Quick reference guide to the new oral anticoagulants.

    Science.gov (United States)

    Hurst, Katherine; Lee, Regent; Handa, Ashok

    2016-06-01

    After the commissioning of new oral anticoagulants for the treatment and prevention of thrombosis, these medications are now widely used within clinical settings. Increasing numbers of patients present to the health services on anticoagulant medications, and it is therefore imperative for surgeons to be aware of the new therapeutic treatments available and how patients will benefit from such interventions. This review highlights the most pertinent learning points for surgeons regarding the indications, pharmacokinetics, and perioperative management of these new oral medications, as a quick reference guide. PMID:27113315

  9. How we treat bleeding associated with direct oral anticoagulants

    Science.gov (United States)

    Marano, Giuseppe; Vaglio, Stefania; Pupella, Simonetta; Liumbruno, Giancarlo M.; Franchini, Massimo

    2016-01-01

    Direct oral anticoagulants are at least as effective as vitamin K antagonists for the prevention and treatment of thromboembolism. Unfortunately, differently from vitamin K antagonists, they have the great drawback of lacking specific antidotes in the case of bleeding or emergency situations such as trauma, stroke requiring thrombolysis, and urgent surgery. The progressive development of antidotes for these new drugs, which, it is hoped, will become available in the near future, will allow better and safer management of the rapid reversal of their anticoagulant effect. PMID:27136433

  10. How we treat bleeding associated with direct oral anticoagulants.

    Science.gov (United States)

    Marano, Giuseppe; Vaglio, Stefania; Pupella, Simonetta; Liumbruno, Giancarlo M; Franchini, Massimo

    2016-09-01

    Direct oral anticoagulants are at least as effective as vitamin K antagonists for the prevention and treatment of thromboembolism. Unfortunately, differently from vitamin K antagonists, they have the great drawback of lacking specific antidotes in the case of bleeding or emergency situations such as trauma, stroke requiring thrombolysis, and urgent surgery. The progressive development of antidotes for these new drugs, which, it is hoped, will become available in the near future, will allow better and safer management of the rapid reversal of their anticoagulant effect. PMID:27136433

  11. Novel oral anticoagulants in the treatment of cerebral venous thrombosis.

    Science.gov (United States)

    Feher, Gergely; Illes, Zsolt; Komoly, Samuel; Hargroves, David

    2016-08-01

    Cerebral venous thrombosis (CVT) is an uncommon cause of stroke with extremely diverse clinical features, predisposing factors, brain imaging findings, and outcome. Anticoagulation is the cornerstone of CVT management, however, it is not supported by high-quality evicence. Novel oral anticoagulants (NOACs) have been extensively studied in patients with deep vein thrombosis, pulmonary embolism and non-valvular atrial fibrillation. The aim of our work was to review the available evidence for NOACs in the treatment of CVT. Based on our literature search there is insufficient evidence to support the use of NOACs in CVT, although case series with rivaroxaban and dabigatran have showed promising results. PMID:25994451

  12. Management of acute stroke in patients taking novel oral anticoagulants

    OpenAIRE

    Hankey, Graeme J; Norrving, Bo; Hacke, Werner; Steiner, Thorsten

    2014-01-01

    Each year, 1·0–2·0% of individuals with atrial fibrillation and 0·1–0·2% of those with venous thromboembolism who are receiving one of the novel oral anticoagulants (dabigatran, rivaroxaban, or apixaban) can be expected to experience an acute ischemic stroke. Additionally, 0·2–0·5% of individuals with atrial fibrillation who are receiving one of the novel oral anticoagulants can be expected to experience an intracranial hemorrhage. This opinion piece addresses the current literature and offer...

  13. [Serious surgical complications associated with chronic anticoagulant therapy].

    Science.gov (United States)

    Pitrák, V; Hadacová, I; Hochová, I; Hoch, J

    2001-06-01

    Chronic anticoagulant treatment is administered mostly for cardiological reasons. Cumarin derivatires are used in the majority of cases (Warfarin, Pelentan). It is necessary to monitor this treatment regularly and to control the dose according to the INR value. Different complications can occur; the haemorrhage represents a serious one. The authors discuss several aspects of anticoagulant therapy and possible prevention of the complications. The importance of the problems is demonstrated on the authors' clinical experience--two cases of haemorrhage after Warfarin administration simulating an acute surgical event. PMID:11482149

  14. Novel oral anticoagulants in the treatment of cerebral venous thrombosis

    DEFF Research Database (Denmark)

    Feher, G; Illes, Z; Komoly, S;

    2015-01-01

    Cerebral venous thrombosis (CVT) is an uncommon cause of stroke with extremely diverse clinical features, predisposing factors, brain imaging findings, and outcome. Anticoagulation is the cornerstone of CVT management, however, it is not supported by high-quality evicence. Novel oral anticoagulants...... (NOACs) have been extensively studied in patients with deep vein thrombosis (DVT), pulmonary embolism (PE) and non-valvular atrial fibrillation (NVAF). The aim of our work to review the available evidence for NOACs in the treatment of CVT. Based on our literature search there is insufficient evidence...

  15. Novel Antiplatelet Activity of Minocycline Involves Inhibition of MLK3-p38 Mitogen Activated Protein Kinase Axis.

    Directory of Open Access Journals (Sweden)

    Joseph W Jackson

    Full Text Available Platelets play an essential role in hemostasis and wound healing by facilitating thrombus formation at sites of injury. Platelets also mediate inflammation and contain several pro-inflammatory molecules including cytokines and chemokines that mediate leukocyte recruitment and activation. Not surprisingly, platelet dysfunction is known to contribute to several inflammatory disorders. Antiplatelet therapies, such as aspirin, adenosine diphosphate (ADP antagonists, glycoprotein IIb/IIIa (GPIIb/IIIa inhibitors, and anticoagulants such as warfarin, dampen platelet activity at the risk of unwarranted bleeding. Thus, the development of drugs that reduce platelet-mediated inflammation without interfering with thrombus formation is of importance to combat platelet-associated disorders. We have shown here for the first time that the tetracycline antibiotic, minocycline, administered to HIV-infected individuals reduces plasma levels of soluble CD40L and platelet factor 4 levels, host molecules predominately released by platelets. Minocycline reduced the activation of isolated platelets in the presence of the potent platelet activator, thrombin, as measured by ELISA and flow cytometry. Platelet degranulation was reduced upon exposure to minocycline as shown by mepacrine retention and flow cytometry. However, minocycline had no effect on spreading, aggregation, GPIIb/IIIa activation, or in vivo thrombus formation. Lastly, immunoblot analysis suggests that the antiplatelet activity of minocycline is likely mediated by inhibition of mixed lineage kinase 3 (MLK3-p38 MAPK signaling axis and loss of p38 activity. Our findings provide a better understanding of platelet biology and a novel repurposing of an established antibiotic, minocycline, to specifically reduce platelet granule release without affecting thrombosis, which may yield insights in generating novel, specific antiplatelet therapies.

  16. Novel Antiplatelet Activity of Minocycline Involves Inhibition of MLK3-p38 Mitogen Activated Protein Kinase Axis

    Science.gov (United States)

    Jackson, Joseph W.; Singh, Meera V.; Singh, Vir B.; Jones, Letitia D.; Davidson, Gregory A.; Ture, Sara; Morrell, Craig N.; Schifitto, Giovanni; Maggirwar, Sanjay B.

    2016-01-01

    Platelets play an essential role in hemostasis and wound healing by facilitating thrombus formation at sites of injury. Platelets also mediate inflammation and contain several pro-inflammatory molecules including cytokines and chemokines that mediate leukocyte recruitment and activation. Not surprisingly, platelet dysfunction is known to contribute to several inflammatory disorders. Antiplatelet therapies, such as aspirin, adenosine diphosphate (ADP) antagonists, glycoprotein IIb/IIIa (GPIIb/IIIa) inhibitors, and anticoagulants such as warfarin, dampen platelet activity at the risk of unwarranted bleeding. Thus, the development of drugs that reduce platelet-mediated inflammation without interfering with thrombus formation is of importance to combat platelet-associated disorders. We have shown here for the first time that the tetracycline antibiotic, minocycline, administered to HIV-infected individuals reduces plasma levels of soluble CD40L and platelet factor 4 levels, host molecules predominately released by platelets. Minocycline reduced the activation of isolated platelets in the presence of the potent platelet activator, thrombin, as measured by ELISA and flow cytometry. Platelet degranulation was reduced upon exposure to minocycline as shown by mepacrine retention and flow cytometry. However, minocycline had no effect on spreading, aggregation, GPIIb/IIIa activation, or in vivo thrombus formation. Lastly, immunoblot analysis suggests that the antiplatelet activity of minocycline is likely mediated by inhibition of mixed lineage kinase 3 (MLK3)-p38 MAPK signaling axis and loss of p38 activity. Our findings provide a better understanding of platelet biology and a novel repurposing of an established antibiotic, minocycline, to specifically reduce platelet granule release without affecting thrombosis, which may yield insights in generating novel, specific antiplatelet therapies. PMID:27270236

  17. AMP-activated protein kinase (AMPK) activation regulates in vitro bone formation and bone mass

    OpenAIRE

    Shah, M; Kola, B; Bataveljic, A.; Arnett, T. R.; Viollet, B.; Saxon, L.; Korbonits, M.; C. Chenu

    2010-01-01

    Adenosine 5′-monophosphate-activated protein kinase (AMPK), a regulator of energy homeostasis, has a central role in mediating the appetite-modulating and metabolic effects of many hormones and antidiabetic drugs metformin and glitazones. The objective of this study was to determine if AMPK can be activated in osteoblasts by known AMPK modulators and if AMPK activity is involved in osteoblast function in vitro and regulation of bone mass in vivo. ROS 17/2.8 rat osteoblast-like cells were cult...

  18. The RecX protein interacts with the RecA protein and modulates its activity in Herbaspirillum seropedicae

    Directory of Open Access Journals (Sweden)

    C.W. Galvão

    2012-12-01

    Full Text Available DNA repair is crucial to the survival of all organisms. The bacterial RecA protein is a central component in the SOS response and in recombinational and SOS DNA repairs. The RecX protein has been characterized as a negative modulator of RecA activity in many bacteria. The recA and recX genes of Herbaspirillum seropedicae constitute a single operon, and evidence suggests that RecX participates in SOS repair. In the present study, we show that the H. seropedicae RecX protein (RecX Hs can interact with the H. seropedicaeRecA protein (RecA Hs and that RecA Hs possesses ATP binding, ATP hydrolyzing and DNA strand exchange activities. RecX Hs inhibited 90% of the RecA Hs DNA strand exchange activity even when present in a 50-fold lower molar concentration than RecA Hs. RecA Hs ATP binding was not affected by the addition of RecX, but the ATPase activity was reduced. When RecX Hs was present before the formation of RecA filaments (RecA-ssDNA, inhibition of ATPase activity was substantially reduced and excess ssDNA also partially suppressed this inhibition. The results suggest that the RecX Hs protein negatively modulates the RecA Hs activities by protein-protein interactions and also by DNA-protein interactions.

  19. The RecX protein interacts with the RecA protein and modulates its activity in Herbaspirillum seropedicae

    Energy Technology Data Exchange (ETDEWEB)

    Galvão, C.W. [Departamento de Biologia Estrutural, Molecular e Genética, Universidade Estadual de Ponta Grossa, Ponta Grossa, PR (Brazil); Souza, E.M. [Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Curitiba, PR (Brazil); Etto, R.M. [Departamento de Biologia Estrutural, Molecular e Genética, Universidade Estadual de Ponta Grossa, Ponta Grossa, PR (Brazil); Pedrosa, F.O.; Chubatsu, L.S.; Yates, M.G. [Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Curitiba, PR (Brazil); Schumacher, J.; Buck, M. [Department of Life Sciences, Imperial College London, London (United Kingdom); Steffens, M.B.R. [Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Curitiba, PR (Brazil)

    2012-10-15

    DNA repair is crucial to the survival of all organisms. The bacterial RecA protein is a central component in the SOS response and in recombinational and SOS DNA repairs. The RecX protein has been characterized as a negative modulator of RecA activity in many bacteria. The recA and recX genes of Herbaspirillum seropedicae constitute a single operon, and evidence suggests that RecX participates in SOS repair. In the present study, we show that the H. seropedicae RecX protein (RecX{sub Hs}) can interact with the H. seropedicae RecA protein (RecA{sub Hs}) and that RecA{sub Hs} possesses ATP binding, ATP hydrolyzing and DNA strand exchange activities. RecX{sub Hs} inhibited 90% of the RecA{sub Hs} DNA strand exchange activity even when present in a 50-fold lower molar concentration than RecA{sub Hs}. RecA{sub Hs} ATP binding was not affected by the addition of RecX, but the ATPase activity was reduced. When RecX{sub Hs} was present before the formation of RecA filaments (RecA-ssDNA), inhibition of ATPase activity was substantially reduced and excess ssDNA also partially suppressed this inhibition. The results suggest that the RecX{sub Hs} protein negatively modulates the RecA{sub Hs} activities by protein-protein interactions and also by DNA-protein interactions.

  20. Stimulation of IGF-binding protein-1 secretion by AMP-activated protein kinase.

    Science.gov (United States)

    Lewitt, M S

    2001-04-20

    Insulin-like growth factor-binding protein-1 (IGFBP-1) is stimulated during intensive exercise and in catabolic conditions to very high concentrations, which are not completely explained by known regulators such as insulin and glucocorticoids. The role of AMP-activated protein kinase (AMPK), an important signaling system in lipid and carbohydrate metabolism, in regulating IGFBP-1 was studied in H4-II-E rat hepatoma cells. Arsenic(III) oxide and 5-aminoimidazole-4-carboxamide-riboside (AICAR) were used as activators. AICAR (150 microM) stimulated IGFBP-1 secretion twofold during a 5-h incubation (P = 0.002). Insulin (100 ng/ml) inhibited IGFBP-1 by 80% (P < 0.001), but this was completely abolished in the presence of 150 microM AICAR. The effect of dexamethasone in stimulating IGFBP-1 threefold was additive to the effect of AICAR (P < 0.001) and, in the presence of AICAR, was incompletely inhibited by insulin. In conclusion AMPK is identified as a novel regulatory pathway for IGFBP-1, stimulating secretion and blocking the inhibitory effect of insulin. PMID:11302732

  1. The total protein content, protein fractions and proteases activities of drone prepupae of Apis mellifera due to varrosis.

    Science.gov (United States)

    Zółtowska, Krystyna; Lipiński, Zbigniew; Dmitryjuk, Małgorzata

    2005-01-01

    The proteins level and activities of acid and alkaline proteases in whole body extracts of drone prepupae of Apis mellifera naturally infested with Varroa destructor were studied. The infested and a non-infested group did not differ significantly in their total protein content. However, some differences in protein profiles were found. A lack of three protein fractions of moderate and lower molecular weight in infested prepupae was noted. Moreover, some differences in the quantity of protein in most of the fractions were observed. The activity of acid proteases from infested prepupae was lower (p < 0.05) compared with the activity of these proteases from the non-infested one group. The infested drone had higher activity of alkaline proteases than non-infested but this difference was not statisticaly significant. PMID:16841690

  2. Single amino acid substitutions dissociate fibrinogen-clotting and thrombomodulin-binding activities of human thrombin.

    OpenAIRE

    Wu, Q Y; Sheehan, J P; Tsiang, M; Lentz, S R; Birktoft, J J; Sadler, J E

    1991-01-01

    Thrombin is a serine protease that acts as a procoagulant by clotting fibrinogen and activating platelets and as an anticoagulant by activating protein C in a thrombomodulin-dependent reaction. Fibrinogen and thrombomodulin bind competitively to an anion-binding exosite on thrombin. We prepared recombinant normal human thrombin and mutant thrombins with single amino acid substitutions in order to localize and distinguish the fibrinogen- and thrombomodulin-binding sites. Normal and mutant thro...

  3. Activation of mitogen-activated protein kinase pathway by extremely low-dose ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Keiji; Kodama, Seiji; Watanabe, Masami [Nagasaki Univ., Graduate School of Biomedical Sciences, Nagasaki (Japan)

    2003-07-01

    We demonstrated here that X-ray irradiation at very low doses of between 2 and 5 cGy stimulated activity of a member of mitogen-activated protein (MAP) kinase, the extracellular signal-regulated kinase (ERK) 1/2, in normal human diploid cells. Higher doses of irradiation at more than 1 Gy induced phosphorylation of ERK1/2 and accumulated p53 protein. Phosphorylation of ERK1/2 decreased with dose down to 50 cGy, however, doses of between 5 cGy and 2 cGy phosphorylated ERK1/2 as efficiently as higher doses of X-rays, while the p53 protein level was no longer changed by doses below 50 cGy. ATM-dependent phosphorylation of p53 protein at Ser15 and histone H2AX at Ser139 was only observed at higher doses at more than 10 cGy of X-rays. We found that MEK1 was phosphorylated with both 2 cGy and 6 Gy of X-rays, and that the MEK1 inhibitor, PD98059 decreased phosphorylation of the ERK1/2 proteins induced by 2 cGy or 6 Gy of X-rays. Similar suppressive effect was observed with the specific epidermal growth factor (EGF) receptor tyrosine kinase inhibitor, AG1478. These results indicate that a limited range of low dose ionizing radiation differentially activate ERK1/2 kinases via activation of EGF receptor and MEK, which mediates various effects of cells receiving very low doses of ionizing radiation. (author)

  4. Cordycepin activates AMP-activated protein kinase (AMPK) via interaction with the γ1 subunit

    Science.gov (United States)

    Wu, Chongming; Guo, Yanshen; Su, Yan; Zhang, Xue; Luan, Hong; Zhang, Xiaopo; Zhu, Huixin; He, Huixia; Wang, Xiaoliang; Sun, Guibo; Sun, Xiaobo; Guo, Peng; Zhu, Ping

    2014-01-01

    Cordycepin is a bioactive component of the fungus Cordyceps militaris. Previously, we showed that cordycepin can alleviate hyperlipidemia through enhancing the phosphorylation of AMP-activated protein kinase (AMPK), but the mechanism of this stimulation is unknown. Here, we investigated the potential mechanisms of cordycepin-induced AMPK activation in HepG2 cells. Treatment with cordycepin largely reduced oleic acid (OA)-elicited intracellular lipid accumulation and increased AMPK activity in a dose-dependent manner. Cordycepin-induced AMPK activation was not accompanied by changes in either the intracellular levels of AMP or the AMP/ATP ratio, nor was it influenced by calmodulin-dependent protein kinase kinase (CaMKK) inhibition; however, this activation was significantly suppressed by liver kinase B1 (LKB1) knockdown. Molecular docking, fluorescent and circular dichroism measurements showed that cordycepin interacted with the γ1 subunit of AMPK. Knockdown of AMPKγ1 by siRNA substantially abolished the effects of cordycepin on AMPK activation and lipid regulation. The modulating effects of cordycepin on the mRNA levels of key lipid regulatory genes were also largely reversed when AMPKγ1 expression was inhibited. Together, these data suggest that cordycepin may inhibit intracellular lipid accumulation through activation of AMPK via interaction with the γ1 subunit. PMID:24286368

  5. APPLICATIONS OF PHARMACOGENETIC TESTING FOR PERSONALIZATION OF THERAPY WITH ORAL ANTICOAGULANTS IN RUSSIA

    Directory of Open Access Journals (Sweden)

    D. A. Sychev

    2013-01-01

    Full Text Available The clinical significance of the patient genetic characteristics in the individual pharmacological response to oral anticoagulants is considered. Possible tactics of warfarin dosing and new oral anticoagulants choice on the basis of pharmacogenetic testing as well as indications for this approach in clinical practice are discussed. It should increase efficacy and safety of anticoagulant therapy.

  6. Long-term anticoagulation in patients with coronary disease, and future developments.

    NARCIS (Netherlands)

    Verheugt, F.W.A.

    2008-01-01

    PURPOSE OF REVIEW: As anticoagulant therapy is a cornerstone in the early management of acute coronary syndrome, the question remains whether long-term anticoagulation after discharge will further improve outcome. RECENT FINDINGS: Major trials demonstrated benefit from routine oral anticoagulation w

  7. Activation of purified calcium channels by stoichiometric protein phosphorylation

    International Nuclear Information System (INIS)

    Purified dihydropyridine-sensitive calcium channels from rabbit skeletal muscle were reconstituted into phosphatidylcholine vesicles to evaluate the effect of phosphorylation by cyclic AMP-dependent protein kinase (PK-A) on their function. Both the rate and extent of 45Ca2+ uptake into vesicles containing reconstituted calcium channels were increased severalfold after incubation with ATP and PK-A. The degree of stimulation of 45Ca2+ uptake was linearly proportional to the extent of phosphorylation of the alpha 1 and beta subunits of the calcium channel up to a stoichiometry of approximately 1 mol of phosphate incorporated into each subunit. The calcium channels activated by phosphorylation were determined to be incorporated into the reconstituted vesicles in the inside-out orientation and were completely inhibited by low concentrations of dihydropyridines, phenylalkylamines, Cd2+, Ni2+, and Mg2+. The results demonstrate a direct relationship between PK-A-catalyzed phosphorylation of the alpha 1 and beta subunits of the purified calcium channel and activation of the ion conductance activity of the dihydropyridine-sensitive calcium channels

  8. Multifunctional antimicrobial proteins and peptides: natural activators of immune systems.

    Science.gov (United States)

    Niyonsaba, François; Nagaoka, Isao; Ogawa, Hideoki; Okumura, Ko

    2009-01-01

    In addition to the physical barrier of the stratum corneum, cutaneous innate immunity also includes the release of various humoral mediators, such as cytokines and chemokines, recruitment and activation of phagocytes, and the production of antimicrobial proteins/peptides (AMPs). AMPs form an innate epithelial chemical shield, which provides a front-line component in innate immunity to inhibit microbial invasion; however, this might be an oversimplification of the diverse functions of these molecules. In fact, apart from exhibiting a broad spectrum of microbicidal properties, it is increasingly evident that AMPs display additional activities that are related to the stimulation and modulation of the cutaneous immune system. These diverse functions include chemoattraction and activation of immune and/or inflammatory cells, the production and release of cytokines and chemokines, acceleration of angiogenesis, promotion of wound healing, neutralization of harmful microbial products, and bridging of both innate and adaptive immunity. Thus, better understanding of the functions of AMPs in skin and identification of their signaling mechanisms may offer new strategies for the development of potential therapeutics for the treatment of infection- and/or inflammation-related skin diseases. Here, we briefly outline the structure, regulation of expression, and multifunctional roles of principal skin-derived AMPs.

  9. Mitogen-Activated Protein Kinase-Activated Protein Kinase 2 Deficiency Reduces Insulin Sensitivity in High-Fat Diet-Fed Mice

    NARCIS (Netherlands)

    de Boer, Jan Freark; Dikkers, Arne; Jurdzinski, Angelika; von Felden, Johann; Gaestel, Matthias; Bavendiek, Udo; Tietge, Uwe J. F.

    2014-01-01

    Adipose tissue inflammation is considered an important contributor to insulin resistance. Mitogen-activated protein kinase-activated protein kinase 2 (MK2) is a major downstream target of p38 MAPK and enhances inflammatory processes. In line with the role of MK2 as contributor to inflammation, MK2(-

  10. Mitogen-activated protein kinase activator with WD40 repeats (MAWD) and MAWD-binding protein induce cell differentiation in gastric cancer

    OpenAIRE

    Li, Dongmei; Zhang, Jun; Xi, Yu; Zhang, Lei; Li, Wenmei; Cui, Jiantao; Xing, Rui; Pan, Yuanmin; Pan, Zemin; Li, Feng; Lu, Youyong

    2015-01-01

    Background Our previous proteomic analysis revealed that mitogen-activated protein kinase activator with WD40 repeats (MAWD) and MAWD-binding protein (MAWBP) were downregulated in gastric cancer (GC) tissues. These proteins interacted and formed complexes in GC cells. To investigate the role of MAWD and MAWBP in GC differentiation, we analyzed the relationship between MAWD/MAWBP and clinicopathologic characteristics of GC tissues and examined the expression of E-cadherin and pepsinogen C (PGC...

  11. Cyclic nucleotides and mitogen-activated protein kinases: regulation of simvastatin in platelet activation

    Directory of Open Access Journals (Sweden)

    Hou Ssu-Yu

    2010-06-01

    Full Text Available Abstract Background 3-Hydroxy-3-methyl-glutaryl coenzyme A (HMG-CoA reductase inhibitors (statins have been widely used to reduce cardiovascular risk. These statins (i.e., simvastatin may exert other effects besides from their cholesterol-lowering actions, including inhibition of platelet activation. Platelet activation is relevant to a variety of coronary heart diseases. Although the inhibitory effect of simvastatin in platelet activation has been studied; the detailed signal transductions by which simvastatin inhibit platelet activation has not yet been completely resolved. Methods The aim of this study was to systematically examine the detailed mechanisms of simvastatin in preventing platelet activation. Platelet aggregation, flow cytometric analysis, immunoblotting, and electron spin resonance studies were used to assess the antiplatelet activity of simvastatin. Results Simvastatin (20-50 μM exhibited more-potent activity of inhibiting platelet aggregation stimulated by collagen than other agonists (i.e., thrombin. Simvastatin inhibited collagen-stimulated platelet activation accompanied by [Ca2+]i mobilization, thromboxane A2 (TxA2 formation, and phospholipase C (PLCγ2, protein kinase C (PKC, and mitogen-activated protein kinases (i.e., p38 MAPK, JNKs phosphorylation in washed platelets. Simvastatin obviously increased both cyclic AMP and cyclic GMP levels. Simvastatin markedly increased NO release, vasodilator-stimulated phosphoprotein (VASP phosphorylation, and endothelial nitric oxide synthase (eNOS expression. SQ22536, an inhibitor of adenylate cyclase, markedly reversed the simvastatin-mediated inhibitory effects on platelet aggregation, PLCγ2 and p38 MAPK phosphorylation, and simvastatin-mediated stimulatory effects on VASP and eNOS phosphorylation. Conclusion The most important findings of this study demonstrate for the first time that inhibitory effect of simvastatin in platelet activation may involve activation of the cyclic AMP

  12. Tribomechanical micronization and activation of whey protein concentrate and zeolite

    Indian Academy of Sciences (India)

    Z Herceg; V Lelas; M Brnčić; B Tripalo; D Ježek

    2004-02-01

    Tribomechanics is a part of physics that is concerned with the study of phenomena that appear during milling under dynamic conditions. Tribomechanical micronization and activation (TMA) of whey protein concentrates (WPC) and zeolites (type clinoptilolite) were carried out. Samples of powdered WPC and zeolite were treated with the laboratory TMA equipment. The treatment was carried out at two various rotor speeds: 16,000 and 22,000 r.p.m. at ambient temperature. Analyses of the particle size and distribution as well as the specific area and scanning electron microscopy were carried out on the powdered WPC and zeolite, before and after the TMA treatment. Suspensions of the WPC and zeolite were treated with ultrasound, just before determining the particle size distribution, at 50 kHz. The results showed that tribomechanical treatment causes significant decrease in particle size, change in particle size distribution and increase in specific area of WPC and zeolite. These changes of the treated materials depend on the type of the material, the level of inserting particles, the planned angle of the impact, internal rubbing and the planned number of impacts. The effects found became stronger as the rotor speed of the TMA equipment increased (16,000 to 22,000 rpm). Ultrasonic treatment of suspension of tribomechanically treated WPC resulted infurther breakdown of partly damaged protein globules as proved with the statistic analyses. No further changes in their granulometric composition were caused by ultrasonic treatment of a suspension of tribomechanically treated zeolite.

  13. Multinational development of a questionnaire assessing patient satisfaction with anticoagulant treatment: the 'Perception of Anticoagulant Treatment Questionnaire' (PACT-Q©

    Directory of Open Access Journals (Sweden)

    Bousser Marie-Germaine

    2009-02-01

    Full Text Available Abstract Background The side effects and burden of anticoagulant treatments may contribute to poor compliance and consequently to treatment failure. A specific questionnaire is necessary to assess patients' needs and their perceptions of anticoagulant treatment. Methods A conceptual model of expectation and satisfaction with anticoagulant treatment was designed by an advisory board and used to guide patient (n = 31 and clinician (n = 17 interviews in French, US English and Dutch. Patients had either atrial fibrillation (AF, deep venous thrombosis (DVT, or pulmonary embolism (PE. Following interviews, three PACT-Q language versions were developed simultaneously and further pilot-tested by 19 patients. Linguistic validations were performed for additional language versions. Results Initial concepts were developed to cover three areas of interest: 'Treatment', 'Disease and Complications' and 'Information about disease and anticoagulant treatment'. After clinician and patient interviews, concepts were further refined into four domains and 17 concepts; test versions of the PACT-Q were then created simultaneously in three languages, each containing 27 items grouped into four domains: "Treatment Expectations" (7 items, "Convenience" (11 items, "Burden of Disease and Treatment" (2 items and "Anticoagulant Treatment Satisfaction" (7 items. No item was deleted or added after pilot testing as patients found the PACT-Q easy to understand and appropriate in length in all languages. The PACT-Q was divided into two parts: the first part to measure the expectations and the second to measure the convenience, burden and treatment satisfaction, for evaluation prior to and after anticoagulant treatment, respectively. Eleven additional language versions were linguistically validated. Conclusion The PACT-Q has been rigorously developed and linguistically validated. It is available in 14 languages for use with thromboembolic patients, including AF, PE and DVT patients

  14. Involvement of protein kinase C activation in L-leucine-induced stimulation of protein synthesis in l6 myotubes.

    Science.gov (United States)

    Yagasaki, Kazumi; Morisaki, Naoko; Kitahara, Yoshiro; Miura, Atsuhito; Funabiki, Ryuhei

    2003-11-01

    Effects of leucine and related compounds on protein synthesis were studied in L6 myotubes. The incorporation of [(3)H]tyrosine into cellular protein was measured as an index of protein synthesis. In leucine-depleted L6 myotubes, leucine and its keto acid, alpha-ketoisocaproic acid (KIC), stimulated protein synthesis, while D-leucine did not. Mepacrine, an inhibitor of both phospholipases A(2) and C, canceled stimulatory actions of L-leucine and KIC on protein synthesis. Neither indomethacin, an inhibitor of cyclooxygenase, nor caffeic acid, an inhibitor of lipoxygenase, diminished their stimulatory actions, suggesting no involvement of arachidonic acid metabolism. Conversely, 1-O-hexadecyl-2-O-methylglycerol, an inhibitor of proteinkinase C, significantly canceled the stimulatory actions of L-leucine and KIC on protein synthesis, suggesting an involvement of phosphatidylinositol degradation and activation of protein kinase C. L-Leucine caused a rapid activation of protein kinase C in both cytosol and membrane fractions of the cells. These results strongly suggest that both L-leucine and KIC stimulate protein synthesis in L6 myotubes through activation of phospholipase C and protein kinase C. PMID:19003213

  15. New Activity of a Protein from Canavalia ensiformis

    Directory of Open Access Journals (Sweden)

    Vanya Petkova BOGOEVA

    2014-06-01

    Full Text Available Concanavalin A is a legume lectin which preferentially agglutinates transformed cells and shows antitumor effects on human breast carcinoma cells in vitro and in vivo. It is considered as a new potential antineoplastic agent targeting apoptosis, autophagy, and anti-angiogenesis in preclinical or clinical trials for cancer therapeutics, which has recently become the object of intensive study. In the present investigation, we show the capacity of the lectin to bind manganese, gold, iron, and zinc porphyrins: all potential anticancer agents. The interaction of the legume lectin with the studied compounds has been investigated by tryptophan fluorescence, showing conformational changes within the quaternary and tertiary structures of the protein. The binding of Con A with manganese, gold, and iron porphyrins, as well as adenine, was studied by fluorescence quenching. In contrast, the interaction of Con A with zinc porphyrin caused an increase in Trp fluorescence and a red shift of 10 nm of the emission maximum position. However, the binding of Con A to iron porphyrin was accompanied by a 5 nm blue shift of the emission maximum, and a kD of 0.95 ± 0.13 μM was calculated, respectively. The sigmoidal shape of the curve showed cooperative interactions, which indicated the presence of more than one class of binding site within the Con A molecule for iron porphyrin, confirmed by the Hill slope (h = 1.89±0.46. We have found that the legume lectin interacts with porphyrins and adenine with an affinity (0.14–1.89 μM similar to that of the non-legume lectin, wheat germ agglutinin. In conclusion, the protein Con A shows new binding activity towards porphyrins with anticancer activities and could find prospective application as a drug delivery molecule that specifically targets cancer cells.

  16. Latent Ice Recrystallization Inhibition Activity in Nonantifreeze Proteins: Ca2+-Activated Plant Lectins and Cation-Activated Antimicrobial Peptides.

    Science.gov (United States)

    Mitchell, Daniel E; Gibson, Matthew I

    2015-10-12

    Organisms living in polar regions have evolved a series of antifreeze (glyco) proteins (AFGPs) to enable them to survive by modulating the structure of ice. These proteins have huge potential for use in cellular cryopreservation, ice-resistant surfaces, frozen food, and cryosurgery, but they are limited by their relatively low availability and questions regarding their mode of action. This has triggered the search for biomimetic materials capable of reproducing this function. The identification of new structures and sequences capable of inhibiting ice growth is crucial to aid our understanding of these proteins. Here, we show that plant c-type lectins, which have similar biological function to human c-type lectins (glycan recognition) but no sequence homology to AFPs, display calcium-dependent ice recrystallization inhibition (IRI) activity. This IRI activity can be switched on/off by changing the Ca2+ concentration. To show that more (nonantifreeze) proteins may exist with the potential to display IRI, a second motif was considered, amphipathicity. All known AFPs have defined hydrophobic/hydrophilic domains, rationalizing this choice. The cheap, and widely used, antimicrobial Nisin was found to have cation-dependent IRI activity, controlled by either acid or addition of histidine-binding ions such as zinc or nickel, which promote its amphipathic structure. These results demonstrate a new approach in the identification of antifreeze protein mimetic macromolecules and may help in the development of synthetic mimics of AFPs.

  17. Protective effects of activated protein C on neurovascular unit in a rat model of intrauterine infection-induced neonatal white matter injury.

    Science.gov (United States)

    Jin, Sheng-juan; Liu, Yan; Deng, Shi-hua; Lin, Tu-lian; Rashid, Abid; Liao, Li-hong; Ning, Qin; Luo, Xiao-ping

    2015-12-01

    Activated protein C (APC), a natural anticoagulant, has been reported to exert direct vasculoprotective, neural protective, anti-inflammatory, and proneurogenic activities in the central nervous system. This study was aimed to explore the neuroprotective effects and potential mechanisms of APC on the neurovascular unit of neonatal rats with intrauterine infection-induced white matter injury. Intraperitoneal injection of 300 μg/kg lipopolysaccharide (LPS) was administered consecutively to pregnant Sprague-Dawley rats at embryonic days 19 and 20 to establish the rat model of intrauterine infection- induced white matter injury. Control rats were injected with an equivalent amount of sterile saline on the same time. APC at the dosage of 0.2 mg/kg was intraperitoneally injected to neonatal rats immediately after birth. Brain tissues were collected at postnatal day 7 and stained with hematoxylin and eosin (H&E). Immunohistochemistry was used to evaluate myelin basic protein (MBP) expression in the periventricular white matter region. Blood-brain barrier (BBB) permeability and brain water content were measured using Evens Blue dye and wet/dry weight method. Double immunofluorescence staining and real-time quantitative PCR were performed to detect microglial activation and the expression of protease activated receptor 1 (PAR1). Typical pathological changes of white matter injury were observed in rat brains exposed to LPS, and MBP expression in the periventricular region was significantly decreased. BBB was disrupted and the brain water content was increased. Microglia were largely activated and the mRNA and protein levels of PAR1 were elevated. APC administration ameliorated the pathological lesions of the white matter and increased MBP expression. BBB permeability and brain water content were reduced. Microglia activation was inhibited and the PAR1 mRNA and protein expression levels were both down-regulated. Our results suggested that APC exerted neuroprotective effects

  18. Protein engineering,expression,and activity of a novel fusion protein possessing keratinocyte growth factor 2 and fibronectin

    Institute of Scientific and Technical Information of China (English)

    Wonmo Kang; Junhyeog Jang

    2009-01-01

    Growth factor-induced proliferation and differentiation often require adhesion of cells to the extracellular matrix proteins such as fibronectin(FN).In this study,we aimed to investigate the effect of protein engineering of the keratinocyte growth factor 2(KGF2)fused to the FN on the mitogenic activity of KGF2.The fusion protein(KGF2-FN10),which was expressed in Escherichia coli,showed significantly enhanced mitogenic activity of KGF2 on human keratinocytes.Moreover,KGF2-FN10 fusion protein showed significantly increased activity to differentiate keratinocytes from native KGF2.In conclusion,these results suggest that KGF2-FN10 fusion protein has certain advantages over native KGF2 and may offer a novel strategy to potentiate the therapeutic effect of KGF2.

  19. Site-specific incorporation of redox active amino acids into proteins

    Science.gov (United States)

    Alfonta, Lital; Schultz, Peter G.; Zhang, Zhiwen

    2009-02-24

    Compositions and methods of producing components of protein biosynthetic machinery that include orthogonal tRNAs, orthogonal aminoacyl-tRNA synthetases, and orthogonal pairs of tRNAs/synthetases, which incorporate redox active amino acids into proteins are provided. Methods for identifying these orthogonal pairs are also provided along with methods of producing proteins with redox active amino acids using these orthogonal pairs.

  20. Protein implicated in nonsyndromic mental retardation regulates protein kinase A (PKA) activity

    KAUST Repository

    Al-Tawashi, Azza

    2012-02-28

    Mutation of the coiled-coil and C2 domain-containing 1A (CC2D1A) gene, which encodes a C2 domain and DM14 domain-containing protein, has been linked to severe autosomal recessive nonsyndromic mental retardation. Using a mouse model that produces a truncated form of CC2D1A that lacks the C2 domain and three of the four DM14 domains, we show that CC2D1A is important for neuronal differentiation and brain development. CC2D1A mutant neurons are hypersensitive to stress and have a reduced capacitytoformdendritesandsynapsesinculture. Atthebiochemical level,CC2D1Atransduces signals to the cyclic adenosine 3?,5?-monophosphate (cAMP)-protein kinase A (PKA) pathway during neuronal cell differentiation. PKA activity is compromised, and the translocation of its catalytic subunit to the nucleus is also defective in CC2D1A mutant cells. Consistently, phosphorylation of the PKA target cAMP-responsive element-binding protein, at serine 133, is nearly abolished in CC2D1A mutant cells. The defects in cAMP/PKA signaling were observed in fibroblast, macrophage, and neuronal primary cells derived from the CC2D1A KO mice. CC2D1A associates with the cAMP-PKA complex following forskolin treatment and accumulates in vesicles or on the plasma membrane in wild-type cells, suggesting that CC2D1A may recruit the PKA complex to the membrane to facilitate signal transduction. Together, our data show that CC2D1A is an important regulator of the cAMP/PKA signaling pathway, which may be the underlying cause for impaired mental function in nonsyndromic mental retardation patients with CC2D1A mutation. 2012 by The American Society for Biochemistry and Molecular Biology, Inc.