Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.21.5 (thrombin)
33,306 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Both cationic and anionic detergents were found to precipitate fibrinogen by forming fibrinogen-detergent complexes. These complexes were soluble in distilled water, but the aqueous solutions were very unstable and the complexes precipitated in the presence of salt. In the interaction of fibrinogen with the cationic detergent, stearyltrimethyl-ammonium chloride, approximately 160 molecules of detergent were found to bind to one molecule of fibrinogen. In distilled water, the fibrinogen-stearyltrimethylammonium complex (FG-STA(Cl)) remained soluble in the presence of thrombin [ED 3.4.21.5] although the same peptides were released as those released from fibrinogen. Precipitation of FG-STA(Cl) by salt was found to be closely related to adsorption of the anion of the salt by the complex. Futher addition of salt resulted in solubilization of the precipitate, and the solubilization was also due to further adsorption of the anion onto the precipitate.
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PMID:Interaction of fibrinogen with detergent. 23 94

In the present study the coagulation analyzer SYSMEX CA 6000 (TOA Medical Electronics Co., Kobe, Japan), an analyzer equipped with a photooptical clot detection unit and a cap-piercing system, was evaluated with respect to its technical characteristics in the determination of standard coagulation tests (prothrombin time, activated partial thromboplastin time, thrombin time, fibrinogen, and antithrombin) and in the determination of coagulation single factor activities. In the normal and in the pathological range the intraassay coefficients of variation (CV) and interassay CV for most parameters were below 5% (exceptions: intraassay CV 5.4% for prolonged thrombin time; intraassay CV 9.26% and interassay CV 10.7% for decreased antithrombin; interassay CV 5.62% for fibrinogen in the normal range, intraassay CV 10.1% for fibrinogen greater than 7.0 g/L; intraassay CV 6.36% and interassay CV 11.7% for decreased fibrinogen; interassay CV 11.6% for prolonged activated partial thromboplastin time; interassay CV 6.12% for decreased factor VII). Interference studies with lipemic, icteric, and hemolytic samples showed just minor influences of these abnormal sample characteristics on prothrombin time, activated partial thromboplastin time, fibrinogen, and antithrombin measurements when compared to the results obtained by using mechanical clot detection (STA, Stago Diagnostica, Asnieres-Sur-Seine, France). No carryover was detected in alternating measurements of heparinized (3 U/mL unfractionated heparin) and normal plasma samples. Measurement of the activities of clotting factors V, VII, VIII, and IX showed a good correlation (r=0.993 to r=0.977) between SYSMEX CA 6000 and STA. Our results demonstrate that using SYSMEX CA 6000 analyzer basal routine coagulation testing as well as specialized tests for single factor activities can be performed with satisfactory precision; in particular, the cap-piercing system has no negative effect on the performance of the analyzer.
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PMID:Evaluation of the automated coagulation analyzer SYSMEX CA 6000. 1055 86

Clinical screening tests for blood coagulation that use plasma as samples cannot estimate the participation of platelets, leukocytes, and erythrocytes in blood coagulation system. We developed an assay to evaluate the total coagulation ability of blood and whole blood prothrombin time (WPT) using the principle of prothrombin time with the diluted-tissue factor as a trigger and a newly developed apparatus, STA, viscosity change detection system (electromagnetic clot detection). The activation of platelets by Ca ionophore shortened WPT and increased the expression of CD62P on the platelet surface. WPTs in citrated blood of spontaneous hypertensive rats (SHR) were significantly shorter than those of controls, Wistar Kyoto rats (WKY). Plasma levels of thrombin-antithrombin III (TAT) in SHR were significantly higher than those of WKY. Moreover, WPT and TAT levels were significantly correlated. Based on these results, WPT was found to be useful to estimate the activation of blood coagulation in whole blood.
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PMID:Whole blood prothrombin time using diluted tissue factor is shortened in spontaneous hypertensive rats. 1080 89

The objective of this study is to examine the effects of the most widely used high-molecular-weight cryoprotectants on the coagulation system. Dextran, hydryoxyethyl starch (HES), polyvinyl pyrrolidone (PVP), polyethylene glycol (PEG), and albumin were added at different concentrations in the range between 0.01-1% (w/v) to solvent/detergent-treated plasma. Using a STA/STA Compact coagulation analyzer the following clotting tests were performed: prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), Factor V, and Factor VIII percentage of activity. PVP and PEG caused a significant increase in APTT, a decrease in Factor VIII percentage of activity, and a slight decrease in TT, while PT and Factor V percentage of activity remained unchanged. Dextran, HES, and albumin did not effect the clotting tests. The effect of high-molecular-weight cryoprotectants on platelets was assessed by platelet-induced clot retraction (PICR) and aggregation with thrombin and agglutination with ristocetin. Platelet aggregation and agglutination were unaffected by all cryoprotectants tested; however, PICR was significantly reduced in the presence of PVP or PEG. Possible mechanisms by which PVP and PEG interfere with the coagulation system are discussed. We also raise issues concerning the development of one-step blood cryopreservation techniques which do not require cryoprotectant removal prior to transfusion.
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PMID:Effects of high-molecular-weight cryoprotectants on platelets and the coagulation system. 1092 60

Protein kinase C (PKC)-potentiated inhibitory phosphoprotein of myosin phosphatase (CPI) was detected in human platelets. Like smooth muscle CPI-17, in vitro phosphorylation of platelet CPI by PKC inhibited the activity of myosin phosphatase containing the PP1delta catalytic subunit and the 130-kd myosin-binding subunit (MBS). Treatment of intact platelets with thrombin or the stable thromboxane A(2) analog STA(2) resulted in increased phosphorylation of both CPI and MBS at Thr-696, whereas phorbol myristate acetate (PMA) and the Ca(++) ionophore ionomycin only induced CPI phosphorylation. PMA induced slow adenosine triphosphate (ATP) secretion of fura 2-loaded platelets with no change in cytosolic Ca(++). The PMA-induced increase in CPI phosphorylation preceded phosphorylation of 20-kd myosin light chain (MLC(20)) at Ser-19 and ATP secretion. The PKC inhibitor, GF109203X, inhibited PMA-induced phosphorylation of CPI and MLC(20) with similar IC(50) values. These findings suggest that the activation of PKC by PMA induces MLC(20) phosphorylation by inhibiting myosin phosphatase through phosphorylation of CPI. STA(2)-induced MLC(20) phosphorylation was also diminished but not abolished by GF109203X, even at high concentrations that completely inhibited STA(2)-induced CPI phosphorylation. A combination of the Rho-kinase inhibitor Y-27632 and GF109203X led to a further decrease in STA(2)-induced MLC(20) phosphorylation, mainly because of a significant inhibition of MBS phosphorylation at Thr-696. Inhibition of STA(2)-induced ATP release by Y-27632, GF109203X, or both appeared to correlate with the extent of MLC(20) phosphorylation. Thus, CPI phosphorylation by PKC may participate in inhibiting myosin phosphatase, in addition to the Rho-kinase-mediated regulation of myosin phosphatase, during agonist-induced platelet secretion. (Blood. 2001;97:3798-3805)
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PMID:Protein kinase C-catalyzed phosphorylation of an inhibitory phosphoprotein of myosin phosphatase is involved in human platelet secretion. 1138 19

Vitamin E is one of the most widely used antioxidants in cryopreservation and preservation technology. The objective of this study is to examine the effect of vitamin E on platelets and the coagulation system. Vitamin E was added at different concentrations in the range between 0.25 and 5 mM to donor plasma. Using a STA/STA Compact coagulation analyzer the following clotting tests were performed: prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT). The control clotting times PT (13.80 +/- 0.4 s), APTT (27.4 +/- 2.4 s) and TT (17.6 +/- 0.4 s) remained unchanged in the presence of vitamin E. The effect of vitamin E on platelets was assessed by platelet-induced clot retraction (PICR) and aggregation by thrombin. PICR was unaffected by vitamin E. Platelet aggregation, however, was profoundly inhibited by vitamin E. We found that inhibition of platelet aggregation by vitamin E was concentration dependent: increasing with increasing vitamin E concentration. This inhibitory effect, however, was widely reversible upon dilution of vitamin E with autologous platelet-poor plasma.
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PMID:Effects of alpha-tocopherol on platelets and the coagulation system. 1167 55

It is not yet clear what exact mechanisms are at work in hibernating animals that prevent clot formation and maintain tissue perfusion under conditions of very slow blood flow and increased blood viscosity brought about by the low temperatures. It has been shown that the total amino acid pool increases more then two fold in hibernating animals with taurine accounting for about 50% of this increase [Storey et al., Proc Natl Acad Sci USA 1988; 85(21): 8350-4]. This work investigates the effect of taurine on platelets and the plasma coagulation system. Taurine was added at different concentrations in the range between 5 and 25 mM to donor plasma. Using STA/STA Compact coagulation analyzer the following tests were performed: prothrombin time (PT), activated partial thromboplastin time (APTT), and thrombin time (TT). At the highest concentration tested (25 mM) taurine prolonged TT by 9%. The prolongation was statistically significant but not clinically significant retaining TT within normal limits (16.7-20.7 s). PT and APTT remained unchanged by taurine. The effect of taurine on platelets was assessed by platelet aggregation by thrombin, extent of platelet shape change (ESC) induced by ADP, and thrombelastography. Taurine at 5 mM final concentration inhibited platelet aggregation by 10%. Increasing taurine concentration to 25 mM did not result in a further augmentation of the inhibitory effect. ESC was unaffected by taurine. Clot strength determined by thrombelastography also remained unchanged by taurine.
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PMID:Effect of taurine on platelets and the plasma coagulation system. 1191 31

We examined whether adducin function is regulated through Rho-kinase after agonist stimulation in platelets. A variety of stimuli such as thrombin, STA(2) (a stable analog of TXA(2)), Ca(2+) ionophore, phorbol diester, and shear stress induced phosphorylation of alpha-adducin at Thr445. Preincubation with the Rho-kinase inhibitor Y-27632 in platelets inhibited agonist-induced phosphorylation of alpha-adducin. STA(2) stimulation led to a redistribution of adducin from Triton-insoluble (high speed) fraction (membrane skeleton) to Triton-insoluble (low speed) fraction (cytoskeleton) and detergent-soluble fraction. Phosphoadducin at Thr445 was selectively isolated in the cytoskeletal fraction, whereas phosphoadducin at Ser726 was mainly present in the Triton-soluble fraction. Y-27632 inhibition of STA(2)-induced alpha-adducin phosphorylation at Thr445 inhibited incorporation of alpha-adducin and spectrin into the platelet cytoskeleton, although Y-27632 did not affect phosphorylation of alpha-adducin at Ser726. These results suggest that Rho-kinase regulates the association of alpha-adducin and spectrin with the actin cytoskeleton in platelet activation.
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PMID:Rho-kinase induces association of adducin with the cytoskeleton in platelet activation. 1591 Jul 44

Developmental haemostasis is a concept, now universally accepted, introduced by Andrew et al. in the late 1980's. However, coagulation analysers and reagents have changed significantly over the past 15 years. Coagulation testing is known to be sensitive to changes in individual reagents and analysers. We hypothesised that the reference ranges developed by Andrew et al. may not be appropriate for use in a modern coagulation laboratory. Our study was designed to determine whether a current day coagulation testing system (STA Compact analyser and Diagnostica Stago reagent system) was sensitive to age-related changes in coagulation assays. This is the first large scale study since Andrew et al. to determine the age associated numerical changes in coagulation proteins. Our results confirm the concepts of developmental haemostasis elucidated by Andrew et al. However, our results clearly demonstrate that the absolute values of reference ranges for coagulation assays in neonates and children vary with analyser and reagent systems. The results confirm the need for coagulation laboratories to develop age-related reference ranges specific to their own testing systems. Without this, accurate diagnosis and management of neonates and children with suspected bleeding or clotting disorders is not possible. Finally we present age related reference ranges for D-dimers, TFPI, and endogenous thrombin potential, previously not described.
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PMID:Developmental haemostasis. Impact for clinical haemostasis laboratories. 1649

Reference intervals for coagulation parameters have been rarely determined in dogs for the STA Compact automated coagulation analyzer, so it is the aim of the current study to validate assays and establish reference ranges for its use in canine specimens. Coagulation parameters were assessed in 56 healthy dogs with a median age of 2 years and evenly distributed sex. The 95% reference intervals were as follows: 1-stage prothrombin time = 5.7-8.0 sec; activated partial thromboplastin time (APTT) = 10.0-14.3 sec; thrombin time (TT) = 11.9-18.3 sec; fibrinogen = 1.3-3.1 g/l; antithrombin (AT) = 107.9-128.0%; D-dimer = 0.023-0.65 microg/ml; anti-factor Xa = 0.04-0.26 IU/l; and activated protein C (APC) ratio = 2.0-3.0. Protein C and S activity was markedly below (<-20%) and factor VIII was 2- to 11-fold above the human calibration standard, so a standard curve had to be prepared from canine pooled plasma. Reference intervals for protein C, protein S, and factor VIII were 75.5-118.9%, 74.4-160.5%, and 70.9-136.4%, respectively, compared with a canine standard curve. Streptokinase-activated plasminogen assay was not suitable for dogs. There was no significant impact of sex on hemostasis test results. Factor VIII activity, AT, protein C, protein S, and APC ratio were overestimated in hemolytic plasma, whereas fibrinogen, TT, and APTT were underestimated. Lipemia resulted only in false-high D-dimers. This study provided useful reference intervals for dogs, but some human tests (i.e., protein C, protein S, factor VIII, and plasminogen) required modification.
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PMID:Reference intervals and method optimization for variables reflecting hypocoagulatory and hypercoagulatory states in dogs using the STA Compact automated analyzer. 1990 Dec 80


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