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)

Rhynchophylline (Rhy) inhibited rabbit platelet aggregation induced by arachidonic acid (AA), collagen, and ADP. The values of IC50 were 0.72, 0.74, and 0.67 mmol.L-1, respectively. Rhy reduced the thromboxane B2 (TXB2) generation in PRP induced by collagen but failed to reduce that induced by AA. Rhy suppressed malondialdehyde (MDA) formation in platelet suspension stimulated by thrombin, inhibited the platelet factor 4 (PF4) release. It did not alter intraplatelet cAMP concentration. Rhy 10-20 mg.kg-1 iv showed a significant inhibition of venous thrombosis and cerebral thrombosis in rats.
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PMID:Inhibitory effect of rhynchophylline on platelet aggregation and thrombosis. 131 85

A 13-year-old boy was admitted to this hospital for evaluation of pitting edema of both legs. Three years ago, he had been diagnosed to have nephrotic syndrome. Two and half years ago, because of persistent heavy proteinuria, poor response to steroids and frequent relapse of disease, a renal biopsy was done; characteristics of IgM nephropathy was shown. About a year previously, the patient felt dizziness and weakness of the left side of his body upon awakening one morning. Neurologic examination showed loss of muscle tone, muscle power and deep tendon reflexes. Sensory and cranial nerve function were intact. Blood pressure was normal. The CT scan of brain showed a patch of low attenuation area in the right temporal region, obliteration of the right cortical sulci and mild compression of right lateral ventricle. A diagnosis of nephrotic syndrome with right cerebral infarction was made. The patient's condition became stable two days later after mannitol infusion, correction of electrolytes, and supportive therapy. According to literature, most cases of nephrotic syndrome complicate with renal thrombosis, pulmonary emboli, and deep vein thrombosis. Few cases complicate with cerebral thrombosis and infarction. If patient have low plasma albumin and anti-thrombin III level, hyperfunction of platelet aggregability and use long-term diuretic therapy, they may be at higher risk of thromboembolic complications. If thromboembolic complications exist, anticoagulation treatment should be instituted. Prophylactic therapy with aspirin or dicumarol is not currently recommended.
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PMID:[Nephrotic syndrome complicated with cerebral infarction: report of one case]. 182 17

Acute myocardial infarction is most commonly initiated by fissuring of an atheromatous plaque. Through such fissures the blood is exposed to thrombogenic constituents of the intima, causing thrombotic obstruction of the coronary artery. Why plaque fissuring occurs is not known. Our investigation is to establish which types of plaque undergo fissuring by relating their mechanical with their cellular and biochemical properties; and to quantify the distribution of fissures. Results so far indicate that fissures occur predominantly in plaques with lipid pools in one segment of intima, and that the commonest single site of fissuring is that of maximal stress concentration as predicted by computer modelling. The results also suggest that arterial spasm at the immediate site of fissuring is not involved, as more than half the fissures occur at sites where there is no residual medial smooth muscle. Obstructive coronary thrombosis is initiated in most cases by plaque fissure with local haemorrhage which induces intravascular platelet aggregation. Recent observations with novel techniques have provided evidence that platelet aggregation in vivo is initiated by ADP and potentiated by thromboxane A2 and thrombin, with actual contribution of exposed collagen still undetermined. These observations provide an explanation for the limited effectiveness of any simple platelet-inhibiting drug, including Aspirin, by itself whenever arterial, eg. coronary or cerebral thrombosis is initiated by haemorrhages into atheromatous plaques. On the other hand, Aspirin is significantly effective when myocardial infarction follows unstable angina and when strokes follow transient episodes of cerebral ischaemia.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Coronary thrombosis: pathogenesis and prevention. 210 21

A 38-year-old female with acute lymphoblastic leukemia developed monoplegia of the left upper extremity following chemotherapy for remission induction consisting of vincristine, prednisolone, cyclophosphamide, adriamycin and methotrexate. Hemorrhagic infarction due to thrombosis of the right cortical vein was diagnosed by brain images using computed tomography and magnetic resonance imaging in addition to the clinical course. At this time, a plasma level of fibrinogen measured by the thrombin time method had decreased to 84 mg/dl, while its antigenicity was 276 mg/dl. There was no evidence of activation of the blood coagulation and fibrinolysis system nor of abnormal liver function. A mixing test with normal plasma disclosed the absence of an inhibitory factor against fibrin polymerization in her plasma. Fibrinogen levels as assessed by the thrombin time method recovered to the antigenicity level one and half months later. The discrepancy between the activity and antigenicity of fibrinogen indicated the occurrence of acquired dysfibrinogenemia, probably induced by antileukemic agents. Thus, it is suggested that dysfibrinogenemia is a possible cause of cerebral thrombosis in this patient.
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PMID:[Transient dysfibrinogenemia and cerebral thrombosis following remission induction therapy for acute lymphoblastic leukemia]. 224 26

Recent progress in the measurements of the hemostatic markers enables us to assess the detailed profiles of hemostatic activation in various diseases. To evaluate the degree of hemostatic system activation in patients with cerebral thrombosis, detailed coagulation studies were performed in 28 patients with acute-phase cerebral thrombosis and in 36 with chronic-phase cerebral thrombosis, together with 6 with chronic-phase cerebral hemorrhage and 37 age-matched healthy volunteers. In both acute-phase and chronic-phase cerebral thrombosis, plasma levels of thrombin-antithrombin III complex, plasmin-alpha 2-plasmin inhibitor complex and D-dimer were significantly higher, and antithrombin III and protein C were significantly lower than those in the normal group. Plasma fibrinogen concentration was significantly higher in chronic-phase cerebral thrombosis than that in chronic-phase cerebral hemorrhage. No significant difference was found in these variables between acute-phase and chronic-phase cerebral thrombosis. In addition, there was no difference in these parameters between chronic phase cerebral hemorrhage and normal subjects. These findings indicate that a sustained activation of coagulation and fibrinolysis is present in cerebral thrombosis, and it might contribute to the pathogenesis of cerebral thrombosis.
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PMID:Sustained activation of blood coagulation in patients with cerebral thrombosis. 748 75

We studied the effect of antiplatelet therapy not only on the secondary prevention of stroke but also on the suppression of vascular damages in patients with cerebral thrombosis at the chronic phase. We measured von Willebrand factor (vWF) as a marker for the endothelial system, and coagulation and fibrinolytic parameters in addition to platelet functions. The platelet aggregation and markers for platelet activation were monitored for the adequate inhibition of platelets. Twenty-one patients were treated with 200 mg ticlopidine. 9 patients with 100 mg ticlopidine and 60-150 mg acetylsalicylic acid, and 18 patients with 200 mg cilostazol daily. The mean duration of follow up was 8.4 +/- 3.0 months. A patient was attacked by a recurrent stroke, but no fatal vascular events occurred during the period. A significant decrease was observed in the collagen- and ADP-induced platelet aggregation and markers for platelet activation such as platelet factor 4 (PF4) and beta-thromboglobulin (beta TG) by the antiplatelet therapy. In addition, the activities of coagulation factor VIII (FVIII) and vWF, markers for vascular damages, showed a significant decrease. The results suggest that the antiplatelet therapy could ameliorate the vascular damage through the inhibition of platelet function. Moreover, thrombin-antithrombin III complex (TAT) and alpha 2-plasmin inhibitor-plasmin complex (PIC), markers for the activation of coagulation and fibrinolytic systems, decreased significantly, suggesting that the treatment inhibits the activation of coagulation and fibrinolytic systems induced by the platelet activation. The activities of FVIII and vWF decreased significantly when the level of beta TG or that of PF4 lowered sufficiently by the treatment.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Antiplatelet therapy in patients with cerebral thrombosis at the chronic phase--assessment of its effect on coagulation and fibrinolytic parameters]. 799 82

Two girls, 22 months and 12 years of age, presented with repeated cerebral infarctions in association with primary antiphospholipid syndrome. The younger patient also suffered from protein C deficiency, while the other one had protein S and complement C4 deficiencies. All other causes of cerebral infarction were excluded; however, vasculitis remains a possibility in one patient. Both girls developed spastic tetraparesis as a sequela of the previous infarctions. The two patients were treated with aspirin and prednisone, with remission of the infarctions during the next 8 months of observation. A primary deficiency of protein C or S is proposed which would produce cerebral thrombosis with exposure of phospholipids; this thrombosis then, like antigens, would generate antibodies acting on the thrombin-thrombomodulin complex, exacerbating the thrombotic process. The association of complement C4 deficiency is an additional risk factor.
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PMID:Childhood stroke associated with protein C or S deficiency and primary antiphospholipid syndrome. 845 4

Platelet aggregation induced by collagen is enhanced in patients with cerebral thrombosis [1], and platelet aggregates and activation products such as beta-thromboglobulin appear in the circulation, particularly during the acute phase [2]. It is known that the presence of activated platelets markedly amplifies thrombin generation by the prothrombinase complex. Platelet aggregation, for which thrombin is the most potent stimulator, is effected by the activation of the thrombin receptor. Activated platelets likely provide the principal surfaces on which intrinsic coagulation factors and prothrombinase assemble in vivo. Moreover, the blood coagulation cascade is simultaneously enhanced during the acute phase of cerebral infarction, resulting in thrombin production and fibrin formation [3]. Cerebral arterial thrombosis is thought to be initiated by rupture of atherosclerotic plaque. Platelets adhere to the constituents of the plaque, and platelet aggregation and the formation of thrombin occur rapidly. The presence of activated platelets involving thrombin generation in cerebral infarction remains to be further clarified. The present study in patients with acute cerebral infarction was undertaken to determine whether argatroban, a direct thrombin inhibitor, is effective in inhibiting collagen-induced platelet aggregation. It is well known that argatroban inhibits not only thrombin cleavage of fibrinogen with a Ki of 19 nM, but also thrombin-mediated platelet activation with a Ki of 40 nM [4]. We evaluated whether the sensitivity of platelets to collagen is increased in the presence of a trace amount of thrombin associated on platelets, at a concentration that does not induce platelet aggregation in acute cerebral infarction. The study also measured the inhibitory effect, if any, of the addition of argatroban during platelet hyperactivation induced by collagen.
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PMID:Inhibition of collagen-induced platelet aggregation by argatroban in patients with acute cerebral infarction. 936 77

An adult woman diagnosed with cerebral thrombosis following a caesarean section was found to have severely prolonged thrombin and reptilase times. Five other family members also had prolonged, but variable, thrombin and reptilase times. Analysis of purified fibrinogen on reducing SDS-PAGE revealed an additional band, in all family members, which migrated immediately below the normal B beta band. Western blotting indicated that this band was a gamma chain and endoglycosidase-F digestion established that it contained an additional oligosaccharide side chain. Partial acid hydrolysis localized the new oligosaccharide to the C-terminus of the gamma chain. Amplification of this region by PCR and subsequent DNA sequencing demonstrated a single base substitution altering the normal 380 Lys (AAG) codon to Asn (AAT), producing a new Asn-Lys-Thr glycosylation site. The propositus and one other family member were homozygous for this mutation but the remaining four family members were heterozygous. The polymerization of purified fibrin monomers from the propositus was grossly abnormal; however, the polymerization curve was almost normalized by the removal of terminal sialic acid residues. This suggests that the polymerization defect was primarily caused by additional negatively charged sialic acid residues present on the new oligosaccharide. Further analysis of the D domain of purified fibrinogen established that calcium binding to the high affinity site remained unaffected by the bulky carbohydrate side chain or negatively charged sialic acid residues.
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PMID:Fibrinogen Kaiserslautern (gamma 380 Lys to Asn): a new glycosylated fibrinogen variant with delayed polymerization. 940 Oct 66

Argatroban is a direct antithrombin agent developed for the first time by Okamoto et al in 1978. Unlike heparin, it manifests its anticoagulant effect by binding directly to the active site of thrombin. A phase II double-blind comparative study was conducted in 52 facilities with a placebo control. The drug was administered by a slow intravenous infusion at 60 mg/d for the first 2 days and then at 10 mg twice daily for the subsequent 5 days. Glycerol was used concomitantly as a basic therapy for both the argatroban and placebo groups. The results demonstrated superior improvements, particularly in neurological symptoms (motor paralysis) and daily living activities (walking, standing up, continuous sitting, and eating), in the argatroban group compared with the placebo group. These improvements were observed from the early stage of administration. It was also found that administration of the drug in the early stage of the disease gave better results. In the present study, although a hemorrhagic cerebral infarct occurred in one case in the argatroban group, this seemed to be no different from a spontaneous incidence, as it also occurred in two cases in the placebo group. Symptoms were not aggravated in any of the cases. These results indicate that argatroban is an effective and safe drug for the treatment of acute cerebral thrombosis.
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PMID:Effect of the thrombin inhibitor argatroban in acute cerebral thrombosis. 946 25


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