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)

Anticoagulation regimens vary according to surgeon, nature of the valve (mechanical or biological), its position and other risk factors for stroke. The American College of Chest Physicians (2001) have made the following recommendations to protect patients with prosthetic heart valves from developing a stroke: (i) For mechanical heart valves: Anticoagulation with Warfarin at an INR range 2-3 for patients with a bileaflet mechanical valve in the aortic position; (ii) in the mitral position, an INR of 2.5-3.5 is recommended; an alternative recommendation is an INR of 2-3 in combination with aspirin (80 mg/day); and (iii) in patients with a mechanical valve and a history of systemic embolization, an INR of 2.5-3.5 combined with low-dose aspirin (80-100 mg) is recommended; when Warfarin therapy is initiated, the doses for patients aged <70 years is 4 mg, and for patients aged >70 years it is 3 mg. While it is important to recognize that the therapeutic range for Warfarin is narrow, recommendations have also been established to manage patients with high INRs and for the temporary discontinuation of anticoagulant therapy when they undergo surgical procedures. Rapid anticoagulation can be achieved either with unfractionated heparin or with low-molecular weight heparin (LMWH). Heparin is initiated with an intravenous bolus of 80 U/kg bodyweight, and an infusion of 18 U/kg/h. The activated thromboplastin time should be 60-80 s. An alternative to intravenous heparin is subcutaneous LMWH, which is prescribed in a mg/kg dose. In the event of valve thrombosis in patients who are hemodynamically unstable, surgical exploration with thrombectomy is indicated, with or without valve replacement. In patients who are hemodynamically stable, thrombolytic therapy is recommended initially.
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PMID:Anticoagulation management of valve replacement patients. 1184 22

The aim of this study was to evaluate coagulative and hemorheologic assessment in patients with dilatative cardiomyopathy with or without spontaneous echo contrast (SEC). We studied 45 patients, 35 males and 10 females (mean age 72.1 +/- 9.2). We measured whole blood viscosity, plasmatic fibrinogen, prothrombin time (PT), activated partial thromboplastin time (aPTT), D-dimer and red cell morphology with Zipursky-Forconi method. Transthoracic and transesophageal echocardiography was performed in all patients to evaluate the presence of SEC in left atrium. We divided all the patients into two groups: the 1st group of 20 patients with SEC and Atrial Fibrillation (AF) in 80% of cases, and the 2nd group of 25 patients without SEC and AF in 31%. Our results show that in patients with SEC there is a statistically significant increase of whole blood viscosity and plasma fibrinogen in comparison with patients without SEC. Red cell morphology in all patients demonstrates a reversed EMI. D-Dimer, was out of the normal range in about 1/3 of the patients in both groups. An analysis of our results points out that in patients with SEC and AF, with a major risk factor for cardioembolic stroke, we have alterations of hemorheologic assessment with an increase of whole blood viscosity and fibrinogen that seems to be caused by an increase of red cells aggregability favoured by fibrinogen. Our conclusions are that SEC in patients with dilatative cardiomyopathy and AF is an important in vivo indicator of hemorheologic imbalance and an important marker for cardioembolic risk stroke evaluation.
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PMID:Spontaneous echo-contrast as an in vivo indicator of rheological imbalance in dilatative cardiomyopathy. 1184 14

The protein Z-protein Z-dependent inhibitor complex is a factor Xa inhibitor. Protein Z deficiencies have recently been described in patients with ischemic stroke. As placenta infarction leads to poor pregnancy outcome, we studied protein Z plasma concentrations in nonthrombotic, nonthrombophilic consecutive patients with unexplained pregnancy wastage. A significant amount of protein Z deficiencies was only found in the early fetal loss group (< 1 mg/L; 44 of 200, P < 10(-4)) and mainly in the case of fetal demise between the beginning of the 10th and the end of the 15th week of gestation (odds ratio, 6.7 [3.1-14.8], P < 10(-3)). These deficiencies were not due to partial vitamin K1 deficiency, and at least some of them were constitutional ones. In women, protein Z deficiency may induce an enhanced risk of severe placental insufficiency soon after the connection of maternal and fetal circulations.
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PMID:High frequency of protein Z deficiency in patients with unexplained early fetal loss. 1189 1

An increased concentration of fibrin(ogen) degradation products (FDPs) commonly is used in conjunction with other hemostatic test abnormalities to identify patients with disseminated intravascular coagulation (DIC). Positive FDP results, however, have been observed in dogs without clinical evidence of DIC. The purpose of this study was to evaluate FDP concentrations in a group of clinically ill dogs with a variety of disorders. Dogs included in the study had the following hemostatic parameters evaluated: prothrombin time, activated partial thromboplastin time, fibrinogen concentration, platelet count, and FDP concentration. Two rapid latex agglutination methods were compared for detecting FDP in serum samples (Thrombo-Wellcotest, International Murex Technologies Corp) and plasma samples (FDP Plasma, American Bioproducts Inc). Results of the serum FDP method were positive in 8% (4/50) of the dogs tested: 3 with DIC and 1 with immune-mediated hemolytic anemia and liver disease. Results of the plasma FDP test were positive in 60% (30/50) of the animals tested: 6 with DIC, 3 with confirmed thrombosis, and 21 with a variety of conditions, including neoplasia, immune-mediated hemolytic anemia, pancreatitis, gastric dilatation-volvulus, heat stroke, severe trauma, sepsis, protein-losing nephropathy, liver disease, hyperadrenocorticism, and chronic heart failure. Because the plasma FDP test was positive more frequently than the serum FDP test in ill dogs, it may be more sensitive for the detection of canine FDP.
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PMID:Serum and plasma latex agglutination tests for detection of fibrin(ogen) degradation products in clinically ill dogs. 1202 12

Intracerebral hemorrhage is the major complication associated with antithrombotic and thrombolytic therapy. Despite efforts directed toward achieving hemorrhagic infarction, an ideal animal model of cerebral hemorrhage has not yet to be established. Using the photothrombotic technique in rabbits, we developed a model of cerebral hemorrhage by inducing cyclic flow reductions in the middle cerebral artery (MCA). Furthermore, the hemorrhage increased 4-fold after infusion of heparin at a dose prolonging activated partial thromboplastin time by about three times that of control animals. The photothrombotic occlusion of the MCA is based on a thrombosis induced by endothelial injury through singlet oxygen produced by Rose Bengal injection and green light irradiation (Acta Neuropathol. 72 (1987) 315; Acta Neuropathol. 72 (1987) 326; J. Pharmacol. Toxicol. Methods. 29 (1993) 165). Using a pulse Doppler flowmeter, spontaneous reperfusion of the MCA after the thrombotic occlusion following cyclic flow reductions was observed within 2 h in the majority of animals. This model is unusual with respect to the development of clinical stroke, because of the MCA cyclic flow reductions. Thus it is different from permanent or ischemia/reperfusion MCA occlusion in rodents and may be suitable for studying hemorrhagic risks associated with the use of antithrombotic agents.
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PMID:A novel MCA occlusion model of photothrombotic ischemia with cyclic flow reductions: development of cerebral hemorrhage induced by heparin. 1203 27

Although heparin-derived oligosaccharide(s) (HDO) have been clinically used for the management of neurological disorders, such as stroke and Alzheimer's disease (AD), very little information on the mechanism of their therapeutic action is known. To test the hypothesis that HDO may pass through the blood-brain barrier (BBB) to mediate their effects, a pharmacodynamic (PD) model was developed and the presence of HDO in the cerebrospinal fluid (CSF) was used as a BBB accessibility index. Rats were treated with an ultralow molecular weight (MW) heparin fragment C3 via the intravenous or subcutaneous routes at 5-10 mg/kg. At varying periods, the plasma, CSF, and brain samples were collected, and functional anti-factor Xa activities were measured to quantitate the CSF/plasma ratios (CPR) and the brain uptake. C3 showed CPR of 1.7% and 0.8% after intravenous and subcutaneous injections, respectively. These findings were verified by intravenous administration of tritium-labeled C3 followed by detection of the radioactivity in the CSF and brain homogenates. These data suggest that ultralow MW HDO may pass through the BBB.
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PMID:The blood-brain barrier accessibility of a heparin-derived oligosaccharides C3. 1206 47

The development of treatments for acute neurodegenerative diseases (stroke and brain trauma) has focused on (i) reestablishing blood flow to ischemic areas as quickly as possible (i.e. mainly antithrombotics or thrombolytics for stroke therapy) and (ii) on protecting neurons from cytotoxic events (i.e. neuroprotective therapies such as anti-excitotoxic or anti-inflammatory agents for stroke and neurotrauma therapies). This paper reviews the preclinical data for enoxaparin in in vivo models of ischemia and brain trauma in rats. Following a photothrombotic lesion in the rat, enoxaparin significantly reduced edema at 24 h after lesion when the treatment was started up to 18 h after insult. Enoxaparin was also tested after an ischemic insult using the transient middle cerebral artery occlusion (tMCAO) model in the rat. Enoxaparin, 2 x 1.5 mg/kg i.v., significantly reduced the lesion size and improved the neuroscore when the treatment was started up to 5 h after ischemia. Enoxaparin, administered at 5 h after insult, reduced cortical lesion size in a dose-dependent manner. In permanent MCAO, enoxaparin (5 and 24 h after insult) significantly reduced lesion size and improved neuroscore. A slight and reversible elevation of activated partial thromboplastin time (APTT) suggests that enoxaparin is neuroprotective at a non-hemorrhagic dose. Traumatic brain injury (TBI) is often accompanied by secondary ischemia due in part to edema-induced compression of blood vessels. When enoxaparin, at 0.5 mg/kg i.v. + 4 x 1 mg/kg s.c., was administered later than 30 h after TBI, it significantly reduced edema in hippocampus and parietal cortex. At one week after TBI the lesion size was significantly reduced and the neurological deficit significantly improved in enoxaparin treated animals. Finally, the cognitive impairment was significantly improved by enoxaparin at 48 h to 2 weeks after TBI. The anticoagulant properties of unfractionated heparin and specifically enoxaparin can explain their anti-ischemic effects in experimental models. Furthermore, unfractionated heparin and specifically enoxaparin, have, in addition to anticoagulant, many other pharmacological effects (i.e. reduction of intracellular Ca2+ release; antioxidant effect; anti-inflammatory or neurotrophic effects) that could act in synergy to explain the neuroprotective activity of enoxaparin in acute neurodegenerative diseases. Finally, we demonstrated, that in different in vivo models of acute neurodegenerative diseases, enoxaparin reduces brain edema and lesion size and improves motor and cognitive functional recovery with a large therapeutic window of opportunity (compatible with a clinical application). Taking into account these experimental data in models of ischemia and brain trauma, the clinical use of enoxaparin in acute neurodegenerative diseases warrants serious consideration.
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PMID:Neuroprotective profile of enoxaparin, a low molecular weight heparin, in in vivo models of cerebral ischemia or traumatic brain injury in rats: a review. 1207 May 24

Ischaemic and haemorrhagic stroke may cause haemostatic abnormalities, apart from concomitant brain damage. In this study, some blood coagulation and fibrinolysis parameters were investigated in 30 patients with ischaemic stroke (atherothrombotic) and 30 with haemorrhagic (20 with intracerebral and 10 with subarachnoid haemorrhage) stroke. The following parameters were determined within the first 24h after stroke: prothrombin time (PT%). activated partial thromboplastin time (aPTT). fibrinogen, activity of FVII, antithrombin. plasmin inhibitor (PI) and fibrin D-dimer. Significant decreases in PT%, FVII activity and antithrombin as well as an increase in fibrinogen and D-dimer were noticed in ischaemic stroke and in both groups of patients with haemorrhagic stroke. PI levels were significantly lower in subarachnoid haemorrhage patients compared with those in controls and those in both the intracerebral haemorrhage and the ischaemic stroke patients. With the exception of this difference, there were no other differences between ischaemic stroke and the two types of haemorrhagic stroke. This could indicate that haemostatic abnormalities are a consequence of brain damage rather than primary haemostatic activation during thrombosis and/or bleeding in the acute phase of stroke. A decrease in the plasmin inhibitor could suggest excessive fibrinolysis in subarachnoid haemorrhage.
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PMID:Blood coagulation and fibrinolysis in acute ischaemic and haemorrhagic (intracerebral and subarachnoid haemorrhage) stroke: does decreased plasmin inhibitor indicate increased fibrinolysis in subarachnoid haemorrhage compared to other types of stroke? 1208 38

Patients with protruding aortic atheroma containing mobile emboli are at risk for peripheral emboli and stroke. This risk may possibly be reduced by anticoagulation, but whether or not such patients have an increased prevalence of thrombotic risk factors has not been previously determined. Twenty-two patients were studied (11 with protruding thoracic aortic atheromas and superimposed mobile thrombi on transesophageal echocardiography were compared to 11 age-matched controls). The authors evaluated activated protein C resistance (APC-R) by measuring the prolongation of the partial thromboplastin time (PTT) in response to activated protein C (APC). Concentrations of fibrinogen, antithrombin III (AT III), factor II, factor V, and D-dimer were also determined in all patients. There was significant resistance to APC (a smaller prolongation in PTT) in patients with atheromas and thrombi. They also had significantly higher concentrations of factor II. Factor V and fibrinogen were higher, and AT III lower, in patients than in controls; however, these latter differences did not reach statistical significance. Patients with aortic atheroma and mobile thrombi may have an increased prevalence of thrombotic risk factors. There is significantly increased resistance to activated protein C in patients with protruding atheroma and mobile thrombi in their thoracic aorta. There was also a trend toward elevated fibrinogen, homocysteine, and apo (a) concentrations as well as lower antithrombin III concentrations in these patients.
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PMID:Elevated prothrombin and activated protein C resistance in patients with thoracic aortic atheroma. 1214 47

Activated platelets are implicated in the development of premature arterial vascular diseases, in particular ischemic stroke. Since elevated cytosolic [Ca(2+)](i) is an integrative marker of platelet activation, we determined the generation of Ca(2+) signal in stimulated platelets from 26 young patients recuperating from stroke, 20 patients with symptomatic peripheral arterial disease, and 56 healthy volunteers. Even in the presence of aspirin, the platelets from various individuals showed highly different thrombin-induced Ca(2+) responses. On average, the thrombin-induced Ca(2+) response was increased for platelets from either patient group in comparison to the controls (P <0.04). Relatively more stroke patients had high-responsive platelets (27%, 7/26) than patients with peripheral arterial disease (10%, 2/20) or healthy subjects (4%, 2/56). The average prothrombinase activities of platelets from patients and controls were similar, but 3 out of 6 patients with increased thrombin-induced Ca(2+) responses also exhibited high prothrombinase activity. In a follow-up study, the subject-dependent thrombin-induced Ca(2+) response was found to correlate strongly with the platelet response to protease-activated receptor 1 (PAR1) agonist (r = 0.91), but was not linked to the Pl(A1/2) polymorphism. It is concluded that a significant part of young patients with stroke have platelets with hyperactivity toward thrombin, which is not normalised by aspirin treatment. Furthermore, the subject-dependent variation in thrombin-induced signalling is likely to involve PAR1-mediated platelet activation.
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PMID:Thrombin-induced hyperactivity of platelets of young stroke patients: involvement of thrombin receptors in the subject-dependent variability in Ca2+ signal generation. 1252 41


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