Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00750 (PLA)
 16,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The comparative effects of intravenous aspirin, the synthetic thrombin inhibitor (2R,4R)-4-methyl-1-[N2-(3-methyl-1,2,3,4-tetrahydro-8- quinolinesulfonyl)-L-arginyl]-2-piperidinecarboxylic acid monohydrate (Argatroban) and F(ab')2 fragments of monoclonal antibody 7E3 against platelet glycoprotein IIb/IIIa (7E3-F[ab']2) on thrombolysis, reocclusion and bleeding associated with 0.45 mg/kg body weight bolus injections of recombinant tissue-type plasminogen activator (rt-PA) were studied in a canine coronary artery thrombosis model. Coronary patency was monitored for 2 h both by flow probe and by coronary angiography. Four groups were studied: Group I = pretreated with 17 mg/kg intravenous aspirin (n = 6), Group II = pretreated with 200 micrograms/kg per min intravenous Argatroban for 60 min (n = 5), Group III = pretreated with aspirin and Argatroban (n = 5) and Group IV = pretreated with 0.8 mg/kg intravenous 7E3-F(ab')2 (n = 5). In Group I, reflow occurred in four of six dogs, but did not persist; reflow was induced in Group II in four of five dogs, persisting in one; in Group III, reflow occurred in all five dogs, persisting in four; in Group IV reflow was achieved in four of five dogs, persisting in two. The frequency of persistent reflow in Group III was significantly higher than in the combined Groups I and II (p = 0.012), whereas the time to reflow was significantly shorter in the groups receiving Argatroban than in the aspirin group (median 25 versus 55 min, p = 0.04). There were no significant differences between Groups III and IV.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Comparative effects of aspirin, a synthetic thrombin inhibitor and a monoclonal antiplatelet glycoprotein IIb/IIIa antibody on coronary artery reperfusion, reocclusion and bleeding with recombinant tissue-type plasminogen activator in a canine preparation. 211 21

The effects of heparin and the synthetic competitive thrombin inhibitor (2R,4R)-4-methyl-1-[N2-(3-methyl-1,2,3,4-tetrahydro-8-quinolinesulfon yl)-L-arginyl]-2-piperidinecarboxylic acid monohydrate (Argatroban) on thrombolysis with recombinant tissue-type plasminogen activator (rt-PA) was studied in groups of six or seven rabbits with arterial thrombosis. The model consisted of a whole-blood clot produced in a 1-cm isolated femoral arterial segment with superimposed endothelial damage and distal high-grade stenosis. rt-PA was injected as an intravenous bolus of 0.45 mg/kg body wt at 15-minute intervals until recanalization, or up to a maximum of four boluses. In seven rabbits given an intravenous injection of 17 mg/kg aspirin, rt-PA induced transient reflow in only one animal. In seven rabbits that received intravenous heparin (200 units/kg over 60 minutes), rt-PA administration produced reflow in five animals, which was persistent in two rabbits. Combined administration of aspirin and heparin in seven rabbits was associated with similar rt-PA-induced recanalization. rt-PA administration in six rabbits given intravenous Argatroban (100 micrograms/kg/min for 60 minutes) caused recanalization in five, with persistent patency in three. In six rabbits given aspirin and Argatroban, rt-PA caused recanalization in all, with persistent patency in five animals. Reflow occurred significantly more rapidly with Argatroban (14 +/- 7 minutes) than with heparin (35 +/- 11 minutes), reflow was obtained with fewer boluses of rt-PA in combination with Argatroban (median value of one bolus) than with heparin (median value, three boluses), and reocclusion after reflow was less frequent with Argatroban (0 of 11 versus 5 of 10 rabbits). Furthermore, the degree of thrombolysis determined by pathological analysis was significantly more extensive with Argatroban than with heparin, and patency persisted during a 3-hour observation period, despite elimination of Argatroban from the circulation. Thus, Argatroban, relative to heparin, enhances and sustains thrombolysis with rt-PA. It may offer promise as an adjunctive agent for thrombolytic therapy of arterial thrombosis.
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PMID:In vivo thrombin inhibition enhances and sustains arterial recanalization with recombinant tissue-type plasminogen activator. 212 35

We compared a selective thrombin inhibitor (MCI-9038; Argatroban), a thromboxane A2 (TXA2) receptor antagonist (L-670,596) and a serotonin-2 receptor antagonist (ketanserin) for their ability to hasten clot lysis and delay reocclusion in a canine model of femoral arterial thrombosis. Occlusive thrombosis was induced by insertion of a thrombogenic copper coil. Femoral arterial blood flow velocity (FABFV) was monitored directly and continuously by Doppler flowmetry. Thrombolysis was induced with tissue plasminogen activator (t-PA; 0.8 mg/kg, i.v.), starting 60 min after thrombotic occlusion and continued for 90 min. Ten minutes after occlusion, dogs received an intravenous infusion of either vehicle, MCI-9038 (10 micrograms kg-1 min-1), ketanserin (0.1 mg/kg bolus plus 5 micrograms kg-1 min-1), L-670,596 (1 mg/kg bolus plus 17 micrograms kg-1 min-1) or a combination of L-670,596 and ketanserin. All infusions were discontinued 1 h after stopping the t-PA, and were followed by a 30 min observation period. The times to thrombolysis were similar for all treatments (mean +/- SEM = 47 +/- 3; all groups). MCI-9038 prevented reocclusion, defined as permanent cessation of FABFV during the hour after stopping the t-PA. All dogs receiving MCI-9038 reoccluded within 30 min after stopping its infusion (71 +/- 3 min). Reocclusion occurred in all other dogs, except one vehicle-treated dog and a second dog that received L-670,596 plus ketanserin. Vehicle-treated dogs reoccluded within 23 +/- 8 min. Reocclusion was not delayed significantly by ketanserin, L-670,596 or the combination of the two.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Prevention of reocclusion by MCI-9038, a thrombin inhibitor, following t-PA-induced thrombolysis in a canine model of femoral arterial thrombosis. 212 37

The effect of argatroban, an anti-thrombin agent, on a 1.5 x 6.0 cm caudally-based flap raised on the backs of Wistar female rats was studied. Argatroban was administered to one group via an implanted osmotic pump, and nothing was administered to a control group. In experiment 1, the effect was evaluated by survival length (ratio of length to width) and a statistically significant difference (p < 0.01) was found between the argatroban group and the control group. In experiment 2, at 3 spots along the midline (M1, M2, M3) in each group, ISO2 (a parameter of oxygen saturation) and IHb (a parameter of hemogrobin concentration) were measured with a reflectance spectrophotometer, and FLOW (a parameter of blood flow) and MASS (a parameter of blood mass) were measured with a laser Doppler flowmeter. M1 was a distal spot of flap, M2 was a proximal spot on the flap and M3 was a spot beside the flap used as a control. At M1, flaps in both groups became necrotic. At M2, flaps in the argatroban group survived, whereas those in the control group became necrotic, and each parameter indicated improvement in blood circulation only in the argatroban group. Thus, argatroban, which antagonizes thrombin, can improve microvascular circulation in congestive tissue and consequently help the flap survive. Argatroban has advantages over other agents that have been given to increase the length of the surviving experimented flap. In comparison with heparin, the coagulation time is easier to control. Also argatroban does not dilate peripheral vessels, which may be a demerit of alprostadil. Argatroban also promotes the reaction of plasminogen activator. The serum concentration of argatroban in this study was almost equal to that used clinically. Therefore, argatroban may be useful when elevating a flap clinically.
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PMID:[Effect of argatroban on flap survival length]. 755 23

We examined the adjunctive effect of a novel factor Xa inhibitor, YM-60828, on vessel patency and blood loss from the operation site after successful thrombolysis with a modified tissue-type plasminogen activator (moPA) in an electrically-induced carotid artery thrombosis model in rats. Five minutes after the induction of occlusive thrombus, a test drug (YM-60828, argatroban, heparin or saline) was administered by i.v. bolus injection followed by continuous infusion. Thrombolysis was induced with moPA by i.v. bolus injection at a dose of 650,000 IU/ kg. YM-60828 at 1 mg/kg i.v. followed by 3 mg/kg/h significantly prevented reocclusion, increased the duration of patency, and improved vessel patency after successful thrombolysis without any significant increase in blood loss from the operation site. Argatroban at 1 mg/kg i.v. followed by 3 mg/kg/h and heparin at 300 U/kg i.v. followed by 150 U/kg/h also significantly improved these parameters, but were accompanied by a significant increase in blood loss. These results suggest that the factor Xa inhibitor YM-60828 may be a potent and useful adjunctive agent with a lower risk of bleeding complications than argatroban and heparin in thrombolytic therapy.
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PMID:Effect of a synthetic factor Xa inhibitor, YM-60828, on blood vessel patency in combination with a thrombolytic agent and on blood loss from the operation site in a rat model of arterial thrombosis. 956 5

Thrombolytic therapy has become a standard treatment for selected patients with acute myocardial infarction (MI). Various thrombolytic agents have been shown to decrease mortality. However, current thrombolytic agents still suffer significant shortcomings, such as a low optimal reperfusion rate delayed reperfusion. and incomplete myocardial perfusion. Furthermore, cyclic flow variations and reocclu.sions remain a significant cause of late morbidity and mortality. In thrombolysis with tissue plasminogen activator (t-PA), heparin seems to play an important role. However, it has several features that suggest that it may not be the optimal adjunct to thrombolytics, including weak and indirect action on thrombin, little access to clot-bound thrombin, inhibition by acute-phase plasma proteins, and its direct stimulation of platelet aggregation. Argatroban (NOVASTAN(R)), a small-molecule, synthetic, direct thrombin inhibitor, has several potential advantages over heparin, and prior studies suggest superior thrombin inhibition with favorable pharmacokinetic and pharmacodynamic properties warranting further investigation The Myocardial Infarction using NOVASTAN (R) and t-PA (MINT) study is a phase II, single-blind, angiographic trial directly comparing heparin versus two doses of argatroban in 120 patients with ST-elevation MI who present within 6 hours of symptom onset. The primary objective of the MINT trial is to assess the TIMI grade 3 flow and TIMI Frame Count at 90 minutes after the initiation of t-PA. This trial will also evaluate the safety of the combination of t-PA, argatroban, and aspirin. The incidence of clinical or silent ischemia, will be monitored. All patients will be followed up to 30 days for the composite endpoint of death, nonfatal recurrent myocardial infarction, coronary artery bypass surgery, PTCA, recurrent ischemia, and shock/new-onset heart failure.
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PMID:A Randomized, Blinded Study of Two Doses of Novastan(R) (Brand of Argatroban) Versus Heparin as Adjunctive Therapy to Recombinant Tissue Plasminogen Activator (Accelerated Administration) in Acute Myocardial Infarction: Rationale and Design of the Myocardial Infarction using Novastan(R) and T-PA (MINT) Study. 1060 50

When endothelial cells are exposed to thrombin, they become perturbed and acquire thrombogenic properties. Argatroban is an arginine derivative, synthetic small molecule that binds to the active site of thrombin and inhibits its catalytic activity. Therefore, the effects of argatroban on endothelial cells, which had been injured by thrombin, were investigated. The established endothelial cell line, TKM-33, which had been cloned from human umbilical vein endothelial cells, was used. Endothelial cells produce plasminogen activator (PA) to prevent thrombosis and maintain the blood flow. When the endothelial cells were injured by thrombin, secretion of plasminogen activator inhibitor-1 (PAI-1) increased and then the PA activity proportionally decreased. The treatment of endothelial cells with argatroban after thrombin injury did not restore their reduced PA activity. However, the treatment of endothelial cells with argatroban prior to thrombin injury resulted in inhibiting the induction of PAI-1 secretion. Thus, pretreatment of endothelial cells with argatroban suppresses the inhibition of their PA activity by thrombin. Since the effect of thrombolytic agent may be modified by the fibrinolytic factors produced by the endothelial cells, the activity of staphylokinase (SAK) was measured in the presence of endothelial cells that had been injured by thrombin. SAK is a newly developed thrombolytic agent. SAK activity in the presence of injured endothelial cells by thrombin was lower than that in the presence of endothelial cells without thrombin injury. However, treatment of endothelial cells with argatroban prior to thrombin injury revealed higher SAK activity than that after thrombin injury. These findings indicate that argatroban pretreatment prevents thrombin injury of endothelial cells, which may then maintain their physiological function.
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PMID:The effect of argatroban on injured endothelial cells by thrombin. 1108 83

ARGAMI was designed to assess safety and efficacy of argatroban compared with heparin as adjunctive treatment to alteplase in the treatment of patients with acute myocardial infarction. ARGAMI consisted of an open-dose finding study (35 patients) followed by a placebo-controlled study with double dummy technique and 2:1 (argatroban:heparin) randomization. An argatroban dosage of 100 microg/kg bolus plus 3 microg/kg/min infusion for 72 hours was selected for the randomized study in which 82 patients were allocated to argatroban and 45 to heparin (5000 U intravenous bolus, 1000 U/h infusion). Patency of the infarct-related artery (Thrombolysis in Myocardial Infarction [TIMI] grade 2 or 3 flow) after 90 minutes was obtained in 62 patients (76%) allocated to argatroban versus 37 patients (82%) allocated to heparin (p=ns). Angiograms after 24 hours and 5 to 10 days showed low reocclusion rates in both groups. Bleeding complications were observed in 16 patients allocated to argatroban (19.5%) and in 9 patients allocated to heparin (20.0%). One patient allocated to heparin suffered from hemorrhage stroke. Argatroban, given as adjunctive treatment to alteplase, is tolerated well in patients with acute myocardial infarction. Safety and efficacy of the combination alteplase and argatroban (with this dose regimen) are similar to those of alteplase and heparin.
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PMID:Argatroban and alteplase in patients with acute myocardial infarction: the ARGAMI Study. 1112 43

The minimal cost algorithm (MCA) commonly used for quantitative coronary arteriography has limitations in definition of complex lesion morphology. A gradient field transform (GFT) algorithm has been designed for the better analysis of complex lesions. We compared MCA with GFT in angiograms of 125 patients in the Myocardial Infarction with Novastan and t-PA (MINT) trial. Lesion border definition was rated as one (poor), two (good), or three (very good). While MCA- and GFT-derived reference diameters (RDs) were similar, GFT yielded smaller minimal lumen diameter (MLD) than MCA by 0.22 +/- 0.31 mm (P < 0.01), and the difference between GFT- and MCA-derived MLDs increased with decreasing MLD. Mean percent diameter stenosis (% DS) was 9.1% +/- 11.1% greater by GFT (P < 0.001). Lesion border definition in simple lesions was similar (not significantly different). However, in complex lesions GFT performed better (2.49 +/- 0.61 vs. 2.11 +/- 0.74; P < 0.05). Thus, GFT appears to improve analysis of complex lesions compared to MCA. GFTs role in angiographic trials and clinical practice deserves further study.
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PMID:Comparison of two different methods of quantitative coronary angiography in patients with acute coronary syndromes. 1194 89

Effects of (2R,4R)-4-methyl-1-[N(2)-(3-methyl-1,2,3,4-tetrahydro-8-quinolinesulfonyl)-L-arginyl]-2-piperidine-carboxylic acid monohydrate (argatroban) and unfractionated heparin (UFH) were compared with respect to thrombus formation and tissue-type plasminogen activator (t-PA)-induced thrombolysis in a microvasculature thrombosis model. The antithrombotic activities of anticoagulants were evaluated with respect to the time required for the initiation of thrombus formation (T(i)) and the time required for the thrombus to stop blood flow (T(s)). The effects of anticoagulants administered with t-PA were evaluated by percent stenosis of the vessel and percent area of the thrombus. Argatroban (1-3 mg/kg/bolus) significantly prolonged T(i) and T(s) in a dose-dependent fashion compared to control. Argatroban (3 mg/kg/bolus) significantly prolonged both the T(i) and T(s) more effectively than UFH (100 anti-XaU (a-XaU)/kg/bolus), despite equivalent prolongation of the activated partial thromboplastin time (aPTT). Higher doses of UFH (300-500 a-XaU/kg) were required to significantly prolong T(i) and T(s), but at these doses, UFH caused over-prolongation of aPTT (>180 s), which might consequently cause bleeding complications. Argatroban (0.1-0.3 mg/kg/h) significantly accelerated thrombolysis by t-PA in both a dose- and time-dependent fashion. Although argatroban (0.1-0.2 mg/kg/h) did not significantly prolong the aPTT and bleeding time (BT) as compared with control, it significantly accelerated thrombolysis by t-PA at these doses of lower bleeding risk. Argatroban (0.3 mg/kg/h) significantly enhanced thrombolysis by t-PA, while UFH (12.5 anti-XaU/kg/h) attenuated it again, despite equivalent prolongation of the aPTT and BT. We conclude that argatroban seems to be a more efficient and safer anticoagulant than UFH for the prevention of thrombus formation and acceleration of t-PA-induced thrombolysis.
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PMID:Effects of argatroban and heparin on thrombus formation and tissue plasminogen activator-induced thrombolysis in a microvascular thrombosis model. 1267 32


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