Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Several new drugs for the management of thromboembolic disorders have recently become available. Low-molecular-weight heparins are being evaluated for the prophylaxis of medical and surgical deep venous thrombosis and pulmonary embolism; for the treatment of pre-existing thrombosis; and for cases of coronary syndrome (unstable angina, myocardial infarction), thrombotic and ischemic stroke, interventional cardiology, pregnancy, cancer, and transplantation-associated thrombosis. A chemically synthesized heparin pentasaccharide, which has purely anti-factor Xa activity and does not induce thrombocytopenia, is also in clinical trial. Thrombin inhibitors, such as hirudin and argatroban, are a practical anticoagulant substitute where heparin cannot be used. They are also useful for the management of coronary syndrome and as adjunct therapy. The antiplatelet agent ticlopidine and its analogue, clopidogrel, which does not produce blood dyscrasia, are effective for the secondary prevention of thrombotic stroke and the management of combined arterial thrombotic syndromes. Glycoprotein-targeting antibodies, synthetic derivatives, and peptides (some of which are orally bioavailable) have added a new dimension to the management of arterial thrombosis and high-risk patients having angioplasty. Plasma-derived agents, such as antithrombin III, are available for the management of thrombophilia and disseminated intravascular coagulation. Compression devices and the foot pump, alone and in combination with pharmacologic agents, have been used successfully. Combination therapy using various agents in different proportions have also been found useful. Although there is much enthusiasm in this quickly developing area and clinical trials are demonstrating the antithrombotic efficacy of the new drugs, safety considerations require additional clinical validation. Long-term outcomes and costs also need to be addressed objectively.
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PMID:Current status on new anticoagulant and antithrombotic drugs and devices. 926 11

The effect of antiphospholipid antibodies (aPL) on the action of activated protein C (APC) was examined in 32 patients: 19 with lupus anticoagulant (LA), 6 with anticardiolipin antibodies (aCL), and 7 with LA and aCL. Eighteen patients had a ratio of activated partial thromboplastin time (APTT) with APC to APTT without APC (APTT ratio) <2.06 (cut-off level) and no factor V Leiden mutation; these patients showed APC-resistance (APC-R) phenotype. The mean prolongation of APTT after addition of APC in a control group was 45.3 seconds, with a lower limit of 31.4 seconds. Only 3 of the 18 patients with low APTT ratio had a prolongation of <31.4 seconds; they were classified as true APC-R phenotype, whereas the other 15 patients were classified as spurious APC-R. Of the 3 patients with true APC-R, 2 had deep venous thrombosis, 1 with pulmonary embolism, and the third had recurrent abortion. Of the other 15 patients, 2 had had ischemic stroke, 1 had recurrent abortion, and 12 were asymptomatic. Circulating APC level was measured in 14 of the 18 aPL patients with a low APTT ratio; it was lower than the normal lower limit in 4 patients and within the lower limit in 2. Three of the 4 patients with reduced APC levels had a history of thrombosis. We conclude that patients with aPL who show APC-R phenotype due to a low APTT ratio without the factor V Leiden mutation can be classified into two groups: true and spurious APC-R phenotype. Since those with true APC-R phenotype could have greater thrombotic risk, adequate classification of these patients is important. Moreover, aPL can sometimes interfere with the activation of protein C, thus reducing the circulating levels of APC, and this could constitute another thrombotic risk factor.
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PMID:Activated protein C resistance phenotype in patients with antiphospholipid antibodies. 928 Jan 48

Argatroban, a direct thrombin inhibitor, is used clinically because of its safe and effective antithrombotic action. This drug of low molecular weight shows reversible inhibition of thrombin irrespective of whether thrombin is fibrin-bound or soluble. Optimal anticoagulant effects can easily be attained by monitoring with the activated partial thromboplastin time or whole-blood activated clotting time when a therapeutic range of argatroban equivalent to that of heparin is used. The antithrombotic action is simply detected with a chromogenic substrate assay. The clinical use of the drug in Japan was approved for the treatment of chronic peripheral arterial obstructive disease and acute ischemic stroke. For coronary artery disease in patients with deficiency of antithrombin activities attributable to either antithrombin III or heparin cofactor II deficiency, argatroban is effective as an anticoagulant. Acute coronary occlusion during and after percutaneous transluminal coronary angioplasty can be treated by argatroban as an alternative to heparin. The presence of platelets activated by a trace amount of thrombin is evidenced by modified methods of platelet aggregometry in acute ischemic stroke. Therefore, argatroban can render the platelets insensitive against the platelet hyperaggregation enhanced by thrombin.
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PMID:Development of argatroban, a direct thrombin inhibitor, and its clinical application. 946 23

Transcatheter occlusion of cardiac defects has become an effective and less invasive alternative to open heart surgery. Thromboembolic complications are rare events, after both surgical and transcatheter closure of atrial septal defects [Galal et al.: Eur Heart J 15:1381-1384, 1994]. We report on a case of thrombus formation on the atrial septal defect occluder system (ASDOS) [Sievert et al.: Cathet Cardiovasc Diagn 36:232-240, 1995; Hausdorf et al.: Heart 75:83-88, 1996]. Two days after transcatheter occlusion, the patient suffered an acute stroke due to embolism despite anticoagulation with intravenous heparin. A coagulation disorder with reduced factor XII concentration was deduced as the likely cause. Repeated transesophageal echocardiographic (TEE) studies revealed an involution of the intracardial thrombus within weeks of subsequent anticoagulatory treatment. First off, this case shows that patients with factor XII deficiency are at risk for thromboembolism. Second, it again clarifies that even large amounts of intraartrial thrombotic material may not be seen by transthoracic echocardiography (TTE) and underscores the necessity of performing TEE. Screening patients for coagulation disorders (Quick's value (Q), partial thromboplastin time (PTT)) before they are selected for treatment with thrombogenic devices is indispensable. With regard to their personal history (earlier thromboembolism) and the result of this screening (e.g., prolongation of PTT), quantitative determination of coagulation factors is reasonable. If patients endangered by thromboembolic complications nevertheless undergo ASD occlusion procedures, anticoagulation monitoring requires exceptional attention. Furthermore, it is recommended that TEE should be carried out in these patients 2 days after treatment, since transthoracic echocardiography (TTE) might be unable to detect thrombus formation on the device.
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PMID:Thrombus formation on transcatheter ASD occluder device in a patient with coagulation factor XII deficiency. 947 99

The antiphospholipid antibodies are immunoglobulins able to join negative charge phospholipids. The have been related to a great variety of conditions, specially among connective tissue illness although the idiopathic form seems to be the most frequent. Their presence must be ruled out in cases of young patients with stroke, deep veins thrombosis, acute heart attack and woman suffer multiple abortions and foetal death. These antibodies appear to be related to different clinical entities like Sneddon syndrome. Evans syndrome, "chorea gestationis", migraine. The laboratory determinations are based in direct methods (ELISA, RIA, ...) as well as in indirect ones (activated partial thromboplastin time, reptilase time, ...). The appropriate management and treatment may be based upon clinical expression, in case of arterial thrombosis (type II APS), or deep vein thrombosis (Type II) long term anticoagulation is indicated; Association with pentoxifylline in the case of retinal thrombosis (type IIIa), Stroke (type IIIb) cases may require long term anticoagulation as well as aspirin. Type IV cases are better managed with an individualised treatment.
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PMID:[Clinical manifestations associated with antiphospholipid antibodies]. 958 47

Hydroxyethyl starch (HES) is often used for volume therapy. Since bleeding complications have been reported repeatedly, a strict dose limitation of a maximum of 1,500 ml 6% solution per day is recommended. However, many indications require higher dosages. Bleeding complications are known to be caused by an acquired von Willebrand syndrome. It has been shown that the accumulation of large molecules and their impairment in the coagulation system can be avoided by using HES preparations with a low in vivo molecular weight. However, the effects of a high-dose therapy have not been studied yet. We have investigated, how a 4-day high-dose therapy, using 3,000 ml 6% HES 70/0.5 on the 1st day and 1,500 ml on days 2-4, affects the coagulation system and hemorheological parameters of acute stroke patients. Thromboplastin time, activated partial thromboplastin time and thrombin time showed no significant changes, except for a slight, clinically irrelevant change due to dilution. The subunits of von Willebrand factor VIII showed no significant change. Hematocrit decreased from 42.3 +/- 4.6 to 37.4 +/- 3.9% (p < 0.05) after day 1, reaching 35.3 +/- 4.2% (p < 0.01) at the end of the therapy, demonstrating a substantial volume effect. Plasma viscosity and erythrocyte aggregation decreased slightly, however not significantly. Our study shows that even a high-dose therapy with 6% HES 70/0.5 has no influence on the coagulation system.
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PMID:No coagulation disorders under high-dose volume therapy with low-molecular-weight hydroxyethyl starch. 969 Apr 84

We evaluated 81 thalassaemia major and 4 thalassaemia intermedia patients (48 M, 37 F), median age 17 years; 62/85 patients were HCV-positive, 3/85 HIV-positive, 19/85 were splenectomized. Forty normal healthy children were recruited as the control group. The number of thrombotic events was studied retrospectively. Platelet poor plasma was filtered and quick-frozen at -70 degrees C until time of assay. APC resistance was measured in an activated thromboplastin time and results were expressed as normalized ratio. All tests were done with diluted 1 in 5 (v/v) factor V deficient plasma and with undiluted plasma. Molecular genetic investigation of factor V gene was performed with polymerase chain reaction, followed by digestion of amplified products with restriction enzyme Mnl I. Data obtained with molecular investigation revealed the presence of 4 heterozygous subjects for factor V Leiden (4.7%). Functional tests were able to detect all heterozygotes for factor V Leiden both with undiluted and with diluted plasma, and there were no false negative subjects. However, undiluted plasma revealed a greater number of false positive subjects (n=15) than did diluted plasma. Therefore, tests done with undiluted and diluted plasma revealed a 100% sensitivity, while specificity was 81% for undiluted plasma and 97% for diluted plasma. Only one thrombotic event was observed in one of the 85 studied patients, as a case of stroke in a thalassaemia intermedia patient with APC resistance. In the same patient an additional thrombogenic risk factor was represented by a pronounced haematocrit increase at the beginning of her transfusion regimen.
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PMID:Resistance to activated protein C in thalassaemic patients: an underlying cause of thrombosis. 971 25

Anticoagulant therapy has changed dramatically during the past two years. Low molecular weight heparin has substantially replaced unfractionated heparin as the parenteral anticoagulant of choice. The use of warfarin has substantially increased, especially for prevention of stroke in the setting of atrial fibrillation. It has become clear that warfarin cannot be administered effectively in an unmonitored fixed-dose fashion. The parenteral direct thrombin inhibitor desirudin was shown to be efficacious in the prevention of deep vein thrombosis in man. Small thrombin and factor Xa inhibitors with in vivo oral anticoagulant activity have been identified.
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PMID:Cardiovascular chemotherapy: anticoagulants. 973 18

The cardiovascular, coagulation and haematological effects of prothrombin activator from Tiger Snake (Notechis scutatus) venom were investigated in anaesthetized mechanically ventilated dogs. Infusion caused dose-related systemic hypotension, marked decreases in cardiac output and stroke volume, marked increases in pulmonary artery pressure, pulmonary artery occlusion pressure and pulmonary vascular resistance. Effects occurred within several minutes but abated over 30 to 40 minutes. Evidence of procoagulation included prolongation of prothrombin and partial thromboplastin times and depletion of serum fibrinogen. Thrombocytopenia and leucopenia occurred. All effects were prevented by prior administration of heparin but none by inhaled nitric oxide. Oesophageal echocardiography during infusion identified thrombi within the heart, right ventricular dilatation and dyskinesia. Electrocardiography suggested myocardial ischaemia. Pulmonary thromboemboli were identified histologically post mortem. Cardiovascular effects of the activator were not due to a variety of endogenous substances as indicated by use of antagonists to platelet activating factor and thromboxane A2 indomethacin, dexamethasone, serotonin, ketanserin, histamine, promethazine and ondansetron. Tiger Snake prothrombin activator causes bilateral ventricular failure by thrombotic obstruction of the pulmonary vasculature and possibly by coronary ischaemia.
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PMID:The cardiovascular, coagulation and haematological effects of tiger snake (Notechis scutatus) prothrombin activator and investigation of release of vasoactive substances. 980 10

The carbohydrate-deficient glycoprotein syndromes are a group of recently described autosomal recessive, metabolic defects affecting multiple systems. The disorder is caused by inefficient posttranslational glycosylation of glycoproteins. Patients with the syndrome present early in life with psychomotor retardation, seizures, hypotonia, and stroke-like episodes. They also have dysmorphic features including almond-shaped eyes, constant squint, inverted nipples, and buttock fat pads. One of the features of the syndrome is coagulopathy, and we report here a patient who presented with a prolonged activated partial thromboplastin time, and was subsequently diagnosed with the carbohydrate-deficient glycoprotein syndrome. We also summarize the results of five previously published studies of the coagulation system in these patients. Most of the reported patients are deficient in factor XI, protein C, antithrombin III, and protein S. Other coagulation proteins are less frequently affected. Both bleeding and thrombosis have been observed, yet the cause of the stroke-like episodes remains speculative. The carbohydrate-deficient glycoprotein syndrome is an increasingly recognized multisystem disorder affecting hemostasis, and thus will involve clinical hematologists as part of a multidisciplinary team caring for patients with the syndrome.
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PMID:Coagulation abnormalities in the carbohydrate-deficient glycoprotein syndrome: case report and review of the literature. 988 8


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