The Experts below are selected from a list of 35700 Experts worldwide ranked by ideXlab platform
David J. Moliterno - One of the best experts on this subject based on the ideXlab platform.
-
point of care ecarin Clotting time versus activated Clotting time in correlation with bivalirudin concentration
Thrombosis Research, 2004Co-Authors: Ivan P. Casserly, Joel P Reginelli, Paul H Gibson, William A. Gray, Michael A. Lauer, Dean J Kereiakes, David J. MoliternoAbstract:Abstract Introduction: A thrombin inhibitor management (TIM) point-of-care test based upon the ecarin Clotting time (ECT) has been developed. The ECT has been suggested to more accurately reflect the anti-coagulant effect of direct thrombin inhibitors compared with the activated Clotting time (ACT). We sought to examine the correlation of the TIM-ECT test with bivalirudin concentration in patients undergoing percutaneous coronary intervention (PCI), and to compare the performance of this test with the current standard (i.e., ACT). Materials and methods: In a multicenter study, blood samples were obtained at six pre-defined time-points in 170 consecutive patients undergoing PCI using bivalirudin. For each sample, the TIM-ECT (citrated and non-citrated), ACT, and bivalirudin concentration was determined. Results: Considering samples from all time-points (n=784), the correlations of TIM-ECT citrated, TIM-ECT non-citrated, and ACT with bivalirudin concentration were 0.96, 0.93, and 0.90, respectively. For samples collected at therapeutic levels of bivalirudin (n=353), the correlations of TIM-ECT citrated, TIM-ECT non-citrated, and ACT with bivalirudin concentration were lower, and showed a greater disparity between methods, with correlation coefficients of 0.75, 0.59, and 0.37, respectively. Prediction models based on the measured bivalirudin concentration were developed for TIM-ECT and ACT, and the coefficients of determination (r2) of actual versus predicted TIM-ECT and ACT were 0.91 and 0.81, respectively. Conclusions: In this PCI population, the TIM-ECT point-of-care test and ACT demonstrated a strong correlation with bivalirudin concentration. The TIM-ECT test had a higher correlation with bivalirudin concentration at therapeutic levels of the drug, and for individual samples appears to more consistently reflect the bivalirudin concentration compared with the ACT.
-
correlation of point of care ecarin Clotting time versus activated Clotting time with bivalirudin concentrations
American Journal of Cardiology, 2003Co-Authors: Kandice Kottkemarchant, Joel P Reginelli, Theresa Kaldus, Michael A Lincoff, Marco Roffi, David J. MoliternoAbstract:To rapidly and specifically monitor the anticoagulant effect of direct thrombin inhibitors, a thrombin inhibitor management (TIM) point-of-care test was developed (PharmaNetics, Inc., Morrisville, North Carolina), based upon the ecarin Clotting time (ECT). This method utilizes the enzyme ecarin (from the venom of Echis carinatus) to convert prothrombin to meizothrombin. Meizothrombin catalyzes the conversion of fibrinogen to fibrin and is rapidly inhibited by direct thrombin inhibitors, such as bivalirudin. This assay has the particular advantage of being relatively specific for the effect of direct thrombin inhibitors, because heparins are poor inhibitors of meizothrombin. 1,2 The TIM-ECT test card may provide a more accurate measurement of direct thrombin inhibitor activity than current point-of-care assays. The purpose of this study was to compare the TIM-ECT test and 2 available activated Clotting time (ACT) methods with a central laboratory anti-Factor IIa assay for monitoring bivalirudin-mediated anticoagulation. ••• Consecutive patients who underwent non-emergency percutaneous coronary intervention (PCI) with bivalirudin at The Cleveland Clinic Foundation were enrolled into the study. The protocol was approved by the institutional review board, and all patients gave written informed consent. Patients were not allowed to receive lepirudin, argatroban, abciximab, epti fibatide, or tirofiban 72 hours before PCI. All unfractionated heparin was discontinued 12 hours before PCI and all fractionated heparins 24 hours before PCI. All patients received preprocedural aspirin. Information regarding patient demographics, laboratory data, procedural details, and serial postprocedural creatine kinase (CK, CK-MB) was prospectively collected. Clinical outcomes were assessed to 30-day follow-up. Arterial blood samples were collected at baseline (sample 1), after bivalirudin bolus and infusion initiation (sample 2), after glycoprotein IIb/IIIa inhibitor bolus and infusion initiation (sample 3), during the procedure (sample 4), and before sheath removal (sample 5). Samples were procured from a nonheparinized arterial sheath and were placed into a noncitrated tube (3 ml) and a 3.2% sodium citrate tube (2.7 ml). Immediately at collection, the noncitrated whole blood samples were tested with the Hemochron ACT (International Technidyne, Edison, New Jersey), CoaguChek Pro/DM ACT (Roche Diagnostics, Indianapolis, Indiana), and the TIM-ECT. After this, the citrated whole blood was tested with the TIM-ECT. The remaining citrated blood was promptly centrifuged, and the plasma was aliquoted into cryovials and frozen at 70°C for the bivalirudin concentration assay. The ACT measures the time for whole blood to clot in the presence of an activating substance. 3,4 The Hemochron tube-based system uses a magnet in a rotating glass specimen tube that contains diatomaceous earth.5 As the blood clots, the magnet is displaced from the tube’ s bottom, thereby activating a proximity switch. Hemochron ACT values were truncated at a maximum of 999 seconds. The Pro/DM ACT is a cartridge-based system that uses tissue factor and sulfatides as activating substances. 6 The blood sample is drawn by capillary action into the reagent chamber, where it mixes with the chemical activators. The time from application of blood to cessation of flow within the chamber is detected by an optical system and converted to an ACT equivalent. Pro/DM Clotting times were truncated at a maximum of 500 seconds.
Mitchell S Dushay - One of the best experts on this subject based on the ideXlab platform.
-
insect hemolymph Clotting
Cellular and Molecular Life Sciences, 2009Co-Authors: Mitchell S DushayAbstract:The clot's appearance in different large-bodied insects has been described, but until recently, little was known about any insect clot's molecular makeup, and few experiments could directly test its function. Techniques have been developed in Drosophila (fruit fly) larvae to identify Clotting factors that can then be tested for effects on hemostasis, healing, and immunity. This has revealed unanticipated complexity in the hemostatic mechanisms in these larvae. While the clot's molecular structure is not yet fully understood, progress is being made, and the loss of Clotting factors has been shown to cause subtle immune defects. The few similarities between coagulation in different insect species and life stages, and the current state of knowledge about coagulation in insects are discussed.
-
coagulation in arthropods defence wound closure and healing
Trends in Immunology, 2004Co-Authors: Ulrich Theopold, Kenneth Soderhall, Otto Schmidt, Mitchell S DushayAbstract:Arthropods have open circulatory systems and must seal wounds and keep bacteria from entering the hemocoel using efficient Clotting systems. Enzymes that crosslink the clot include transglutaminase, which is phylogenetically conserved, and phenoloxidase, which is not found in vertebrates. Prophenoloxidase is usually activated through a proteolytic cascade similar to the vertebrate Clotting cascade. The well-characterized Clotting cascade in horseshoe crabs is strongly activated by bacterial elicitors, in contrast to vertebrate Clotting where induction relies more on endogenous signals. Many arthropod Clotting factors are not orthologues of blood Clotting factors, but show novel architectures assembled from domains that are also found in their vertebrate counterparts. The cellular mechanisms that lead to coagulation of blood and hemolymph appear to be similar. Recent findings in Drosophila reveal parallels between developmental processes that involve epithelial fusion and wound healing, enabling genetic dissection of the signal pathways involved. This Review is the first in a series on interactions between haemostasis and inflammation.
-
isolation and characterization of hemolymph Clotting factors in drosophila melanogaster by a pullout method
Current Biology, 2004Co-Authors: Christoph Scherfer, Mitchell S Dushay, Christine Karlsson, Olga Loseva, Gawa Bidla, Akira Goto, Johanna Havemann, Ulrich TheopoldAbstract:Clotting is critical in limiting loss of hemolymph and initiating wound healing in insects as well as in vertebrates [1]. Clotting is also an important immune defense, quickly forming a secondary b ...
Gholam Reza Nazaralipour - One of the best experts on this subject based on the ideXlab platform.
-
Assessment and partial purification of serine protease inhibitors from Rhipicephalus (Boophilus) annulatus larvae Avaliação e purificação parcial dos inibidores da serina protease de larvas do Rhipicephalus (Boophilus) annulatus
2014Co-Authors: S Nabian, Alireza Sazmand, Mohammad Taheri, Mohammad Mehdi Ranjbar, Parastou Youssefy, Gholam Reza NazaralipourAbstract:Ticks are rich sources of serine protease inhibitors, particularly those that prevent blood Clotting and inflammatory responses during blood feeding. The tick Rhipicephalus (Boophlus) annulatus is an important ectoparasite of cattle. The aims of this study were to characterize and purify the serine protease inhibitors present in R. (B.) annulatus larval extract. The inhibitors were characterized by means of one and two-dimensional reverse zymography, and purified using affinity chromatography on a trypsin-Sepharose column. The analysis on one and two-dimensional reverse zymography of the larval extract showed trypsin inhibitory activity at between 13 and 40 kDa. Through non-reducing SDS-PAGE and reverse zymography for proteins purified by trypsin-Sepharose affinity chromatography, some protein bands with molecular weights between 13 and 34 kDa were detected. Western blotting showed that five protein bands at 48, 70, 110, 130 and 250 kDa reacted positively with immune serum, whereas there was no positive reaction in the range of 13-40 kDa. Serine protease inhibitors from R. (B.) annulatus have anti-trypsin activity similar to inhibitors belonging to several other hard tick species, thus suggesting that these proteins may be useful as targets in anti-tick vaccines.
-
Assessment and partial purification of serine protease inhibitors from Rhipicephalus (Boophilus) annulatus larvae.
Revista brasileira de parasitologia veterinaria = Brazilian journal of veterinary parasitology : Orgao Oficial do Colegio Brasileiro de Parasitologia , 2014Co-Authors: S Nabian, Alireza Sazmand, Mohammad Taheri, Mohammad Mehdi Ranjbar, Parastou Youssefy, Gholam Reza NazaralipourAbstract:Ticks are rich sources of serine protease inhibitors, particularly those that prevent blood Clotting and inflammatory responses during blood feeding. The tick Rhipicephalus (Boophlus) annulatus is an important ectoparasite of cattle. The aims of this study were to characterize and purify the serine protease inhibitors present in R. (B.) annulatus larval extract. The inhibitors were characterized by means of one and two-dimensional reverse zymography, and purified using affinity chromatography on a trypsin-Sepharose column. The analysis on one and two-dimensional reverse zymography of the larval extract showed trypsin inhibitory activity at between 13 and 40 kDa. Through non-reducing SDS-PAGE and reverse zymography for proteins purified by trypsin-Sepharose affinity chromatography, some protein bands with molecular weights between 13 and 34 kDa were detected. Western blotting showed that five protein bands at 48, 70, 110, 130 and 250 kDa reacted positively with immune serum, whereas there was no positive reaction in the range of 13-40 kDa. Serine protease inhibitors from R. (B.) annulatus have anti-trypsin activity similar to inhibitors belonging to several other hard tick species, thus suggesting that these proteins may be useful as targets in anti-tick vaccines.
Martin F Lavin - One of the best experts on this subject based on the ideXlab platform.
-
next generation rapid serum tube technology using prothrombin activator coagulant fast high quality serum from normal samples
Clinical Chemistry and Laboratory Medicine, 2019Co-Authors: Kongnan Zhao, Paul P. Masci, Goce Dimeski, John De Jersey, Lambro A Johnson, Michael Grant, Martin F LavinAbstract:Background Incomplete blood Clotting or latent Clotting in serum is a common laboratory problem, especially for patients on anticoagulant therapy or when serum tubes are centrifuged before Clotting is completed. We describe a novel approach to producing high-quality serum using snake venom prothrombin activator complex (OsPA) as an additive in blood collection tubes for non-anticoagulated (normal) individuals. Methods Plasma Clotting assays were performed using a Hyland-Clotek instrument. Blood Clotting was visually observed, and thromboelastography was also performed to determine the important parameters of coagulation. Thrombin generation was assayed using the chromogenic substrate S-2238, and biochemical analytes in the serum were determined on chemistry and immunoassay analysers. Fibrinogen was determined by either ELISA or Clauss fibrinogen assay. Results We initially showed that OsPA had strong coagulation activity in Clotting not only recalcified citrated plasma and recalcified citrated whole blood, but also fresh whole blood in a clinical setting. The use of TEG clearly showed improved speed of Clotting and generation of a firmer clot. We also showed that the use of OsPA to produce serum did not interfere with the determination of commonly measured biochemical analytes. The underlying Clotting mechanism involves a burst of thrombin production at the initial stages of the Clotting process upon contact with prothrombin in blood. Conclusions These results demonstrate rapid generation of high-quality serum, contributing to faster turnaround times with standardised quality samples, for accurate analyte determinations in normal individuals.
Joel P Reginelli - One of the best experts on this subject based on the ideXlab platform.
-
point of care ecarin Clotting time versus activated Clotting time in correlation with bivalirudin concentration
Thrombosis Research, 2004Co-Authors: Ivan P. Casserly, Joel P Reginelli, Paul H Gibson, William A. Gray, Michael A. Lauer, Dean J Kereiakes, David J. MoliternoAbstract:Abstract Introduction: A thrombin inhibitor management (TIM) point-of-care test based upon the ecarin Clotting time (ECT) has been developed. The ECT has been suggested to more accurately reflect the anti-coagulant effect of direct thrombin inhibitors compared with the activated Clotting time (ACT). We sought to examine the correlation of the TIM-ECT test with bivalirudin concentration in patients undergoing percutaneous coronary intervention (PCI), and to compare the performance of this test with the current standard (i.e., ACT). Materials and methods: In a multicenter study, blood samples were obtained at six pre-defined time-points in 170 consecutive patients undergoing PCI using bivalirudin. For each sample, the TIM-ECT (citrated and non-citrated), ACT, and bivalirudin concentration was determined. Results: Considering samples from all time-points (n=784), the correlations of TIM-ECT citrated, TIM-ECT non-citrated, and ACT with bivalirudin concentration were 0.96, 0.93, and 0.90, respectively. For samples collected at therapeutic levels of bivalirudin (n=353), the correlations of TIM-ECT citrated, TIM-ECT non-citrated, and ACT with bivalirudin concentration were lower, and showed a greater disparity between methods, with correlation coefficients of 0.75, 0.59, and 0.37, respectively. Prediction models based on the measured bivalirudin concentration were developed for TIM-ECT and ACT, and the coefficients of determination (r2) of actual versus predicted TIM-ECT and ACT were 0.91 and 0.81, respectively. Conclusions: In this PCI population, the TIM-ECT point-of-care test and ACT demonstrated a strong correlation with bivalirudin concentration. The TIM-ECT test had a higher correlation with bivalirudin concentration at therapeutic levels of the drug, and for individual samples appears to more consistently reflect the bivalirudin concentration compared with the ACT.
-
correlation of point of care ecarin Clotting time versus activated Clotting time with bivalirudin concentrations
American Journal of Cardiology, 2003Co-Authors: Kandice Kottkemarchant, Joel P Reginelli, Theresa Kaldus, Michael A Lincoff, Marco Roffi, David J. MoliternoAbstract:To rapidly and specifically monitor the anticoagulant effect of direct thrombin inhibitors, a thrombin inhibitor management (TIM) point-of-care test was developed (PharmaNetics, Inc., Morrisville, North Carolina), based upon the ecarin Clotting time (ECT). This method utilizes the enzyme ecarin (from the venom of Echis carinatus) to convert prothrombin to meizothrombin. Meizothrombin catalyzes the conversion of fibrinogen to fibrin and is rapidly inhibited by direct thrombin inhibitors, such as bivalirudin. This assay has the particular advantage of being relatively specific for the effect of direct thrombin inhibitors, because heparins are poor inhibitors of meizothrombin. 1,2 The TIM-ECT test card may provide a more accurate measurement of direct thrombin inhibitor activity than current point-of-care assays. The purpose of this study was to compare the TIM-ECT test and 2 available activated Clotting time (ACT) methods with a central laboratory anti-Factor IIa assay for monitoring bivalirudin-mediated anticoagulation. ••• Consecutive patients who underwent non-emergency percutaneous coronary intervention (PCI) with bivalirudin at The Cleveland Clinic Foundation were enrolled into the study. The protocol was approved by the institutional review board, and all patients gave written informed consent. Patients were not allowed to receive lepirudin, argatroban, abciximab, epti fibatide, or tirofiban 72 hours before PCI. All unfractionated heparin was discontinued 12 hours before PCI and all fractionated heparins 24 hours before PCI. All patients received preprocedural aspirin. Information regarding patient demographics, laboratory data, procedural details, and serial postprocedural creatine kinase (CK, CK-MB) was prospectively collected. Clinical outcomes were assessed to 30-day follow-up. Arterial blood samples were collected at baseline (sample 1), after bivalirudin bolus and infusion initiation (sample 2), after glycoprotein IIb/IIIa inhibitor bolus and infusion initiation (sample 3), during the procedure (sample 4), and before sheath removal (sample 5). Samples were procured from a nonheparinized arterial sheath and were placed into a noncitrated tube (3 ml) and a 3.2% sodium citrate tube (2.7 ml). Immediately at collection, the noncitrated whole blood samples were tested with the Hemochron ACT (International Technidyne, Edison, New Jersey), CoaguChek Pro/DM ACT (Roche Diagnostics, Indianapolis, Indiana), and the TIM-ECT. After this, the citrated whole blood was tested with the TIM-ECT. The remaining citrated blood was promptly centrifuged, and the plasma was aliquoted into cryovials and frozen at 70°C for the bivalirudin concentration assay. The ACT measures the time for whole blood to clot in the presence of an activating substance. 3,4 The Hemochron tube-based system uses a magnet in a rotating glass specimen tube that contains diatomaceous earth.5 As the blood clots, the magnet is displaced from the tube’ s bottom, thereby activating a proximity switch. Hemochron ACT values were truncated at a maximum of 999 seconds. The Pro/DM ACT is a cartridge-based system that uses tissue factor and sulfatides as activating substances. 6 The blood sample is drawn by capillary action into the reagent chamber, where it mixes with the chemical activators. The time from application of blood to cessation of flow within the chamber is detected by an optical system and converted to an ACT equivalent. Pro/DM Clotting times were truncated at a maximum of 500 seconds.