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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

From the view point of prevention and treatment of dementia, dementia can be classified into three main groups. The first is treatable or preventable dementia. Unfortunately, this group occupies only 10 or 20% of all demented patients. However, early diagnosis and treatment of diseases belonging to this group are particularly important. The other two groups are Alzheimer-type dementia (ATD) and vascular dementia. Early diagnosis of ATD is still rather difficult. We recently have found that alpha 1-antichymotrypsin (alpha 1-ACT) increases significantly in the serum and cerebrospinal fluid in ATD. Thus, alpha 1-ACT can be used as an antemortem biological marker of ATD. Positron emission CT (PET) is also useful for the early diagnosis of ATD, because decrease in CMRO2 in the unilateral temporo-parietal region occurs in a relatively early stage of this disease. On the other hand, vascular dementia can be said to be becoming one of the treatable or preventable dementias. Vascular dementia is mainly based on cerebral infarction. Therefore, prevention of initial stroke is most essential. For this purpose, correction of risk factors and use of antiplatelet agents in those cases suffering a transient ischemic attack or subjective symptoms are necessary.
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PMID:[Early diagnosis and prevention of dementia in the aged]. 221 6

In this article we describe production compilation, a mechanism for modeling skill acquisition. Production compilation has been developed within the ACT-Rational (ACT-R; J. R. Anderson, D. Bothell, M. D. Byrne, & C. Lebiere, 2002) cognitive architecture and consists of combining and specializing task-independent procedures into task-specific procedures. The benefit of production compilation for researchers in human factors is that it enables them to test the strengths and weaknesses of their task analyses and user models by allowing them to model the learning trajectory from the main task level and the unit task level down to the key-stroke level. We provide an example of this process by developing and describing a model learning a simulated air traffic controller task. Actual or potential applications of this research include the evaluation of user interfaces, the design of systems that support learning, and the building of user models.
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PMID:Production compilation: a simple mechanism to model complex skill acquisition. 1291 82

Reference data on the function of renin-angiotensin-aldosterone system (RAAS) and pharmacological correction of its hyperactivity are summarized and analyzed in the paper. RAAS plays important role in the development and worsening of hypertension, facilitates proliferation of smooth muscle and heart cells. The hyperactivity of RAAS promotes the development of cardiovascular complications, such as myocardial infarction, stroke, increases cardiovascular mortality and morbidity. Pharmacological correction of RAAS hyperactivity decreases hypertension, prevents occlusion of heart and blood vessels, provides anti-ischemic action, vascular and cardiac protection, improves life style, prevents cardiovascular mortality, such as fatal stroke, myocardial infarction and sudden death. b-blocker inhibitors, angiotensin converting enzyme (ACE) inhibitors, angiotensin AT1-receptors blockers are reviewed as first line therapy of essential hypertension and congestive heart failure. ACT inhibitors, AT1- receptor blockers decrease total cholesterol, LDL, but increase HDL, beta-blockers decrease HDL. AT1-blockers are alternative drugs for treatment of cardiovascular diseases in those cases where ACE inhibitors are contraindicated or intolerance exists.
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PMID:[Pharmacological correction of hyperactivity of renin-angiotensin-aldosterone system]. 1644 43

Favorable outcome by hyperacute rt-PA (recombinant tissue-type plasminogen activator) therapy was suggested firstly by randomized controlled trials (RCT) in Japan, and confirmed by the NINDS trial (1995) using alteplase within the initial 3 hours. A phase III clinical trial using open-labeled, single-dose alteplase was carried out in Japan (Japan Alteplase Clinical Trial, J-ACT). The study protocol was almost compatible to that of the NINDS study, except for several modifications including lower dose administration of alteplase (0.6 mg/kg) in the J-ACT than that in the NINDS study (0.9 mg/kg). The clinical backgrounds were almost similar, and frequencies of very favorable outcome at 3-months and symptomatic intracranial hemorrhage were comparable between the studies. The Japanese Government approved the use of intravenous alteplase therapy in October 11, 2005. The Japan Stroke Society published a guideline and gave more than 130 courses for appropriate alteplase therapy immediately after the approval. Clinical results of this therapy were excellent in the initial 21 cases of our hospital. New approaches will open the door to an exciting new era for stroke management. They include MR-based delayed thrombolysis up to 9 hours after stroke onset and ultrasound-enhanced systemic thrombolysis.
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PMID:[Thrombolytic therapy]. 1743 95

A stroke-related loss of corticospinal and corticobulbar pathways is postulated to result in an increased use of remaining neural substrates such as bulbospinal pathways as individuals with stroke are required to generate greater volitional shoulder abduction torques. The effect of shoulder abduction on upper extremity reaching range of motion (work area) was measured in 18 individuals with stroke using the Arm Coordination Training 3-D (ACT(3D)) device. This robotic system is capable of quantifying movement kinematics when a subject attempts to reach while simultaneously generating various levels of active shoulder abduction torque. We have provided data demonstrating an incremental increase of abnormal coupling of elbow flexion for greater levels of shoulder abduction in the paretic limb that results in a reduction in available work area as a function of active limb support. The progressive increase in the expression of abnormal shoulder/elbow coupling can be explained by a progressive reliance on the indirect cortico-bulbospinal connections that remain in individuals following a stroke-induced brain injury.
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PMID:Shoulder abduction-induced reductions in reaching work area following hemiparetic stroke: neuroscientific implications. 1763 33

Japan Alteplase Clinical Trial (J-ACT), a prospective multicenter clinical trial, demonstrated good clinical outcome in patients treated with 0.6 mg/kg of alteplase, being similar to that with 0.9 mg/kg of alteplase in the National Institute of Neurological Disorders and Stroke (NINDS) study. On that basis, intravenous aplteplase therapy was approved in Japan in October, 2005. This therapy resulted in better efficacy and similar safety in our stroke care unit (SCU) as compared to J-ACT or other clinical studies performed outside Japan. Our nation-wide survey demonstrated that the approval of the therapy resulted in dramatic changes in the processes of management for acute stroke patients. Preliminary results of the post-marketing surveillance study of alteplase in Japan suggested similar efficacy and safety profiles of the therapy to those reported by a European study, Safe Implementation of Thrombolysis in Stroke-Monitoring Study (SITS-MOST). There are several limitations and problems in the therapy that will be overcome by new therapeutic strategies including the development of new-generation therombolytic agents having longer therapeutic time window, applications of magnetic resonance imaging techniques, and combination therapies with neuroprotective agents, sonothrombolysis, intraarterial application of the agent, or mechanical thrombectomy.
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PMID:[New era has begun since the approval of thrombolytic therapy for acute ischemic stroke in Japan]. 1919 7

The US Food and Drug Administration (FDA) approved the use of intravenous (IV) recombinant tissue plasminogen activator (rt-PA) in 1996, on the basis of the results of the National Institute of Neurological Disorders and Stroke (NINDS) rt-PA Stroke Study. IV rt-PA therapy at a dose of 0.9 mg/kg has been approved internationally for the treatment of hyperacute ischemic stroke. After a dose comparison study using duteplase and a multicenter study using a single dose of alteplase (Japan Alteplase Clinical Trial: J-ACT), the administration of IV rt-PA therapy at a dose of 0.6 mg/kg was approved in Japan in 2005. Immediately after the approval, the Japan Stroke Society published the Japanese guidelines for this low-dose therapy. Two years after the approval in Japan, the outcome of IV rt-PA therapy in Japan was observed to be comparable to that of NINDS rt-PA therapy and to those published in studies based in Western nations. Several trials have reported predictors of unfavorable outcome for IV rt-PA therapy. Patients with severe strokes (higher NIHSS score, coma), higher age at disease onset, aortic arch dissection, higher blood pressure, higher blood sugar, occlusion of the internal carotid artery (ICA) or tandem lesion of the left ICA and right middle cerebral artery (MCA), or the presence of major early ischemic changes as observed upon computed tomography (CT) or magnetic resonance imaging (MRI), showed a greater probability for unfavorable response to treatment. The results of the randomised 2008 trial conducted by the third European Cooperative Acute Stroke Study (ECASS III) suggested that treatment with IV rt-PA administered 3-4.5 hours after symptom onset can still induce significant improvement in clinical outcomes after an acute ischemic stroke as opposed to a placebo. MRI-based thrombolysis might be safer than standard CT-based thrombolysis. A combination of reperfusion therapies, IV rt-PA and sonothrombolysis, neuroprotective agents or antiplatelet agents may be effective. However, currently available data do not provide conclusive evidence for the safety or efficacy of these combination therapies. Patients having ICA occlusion may require alternatives including a higher dose of alteplase, combined IV/IA thrombolysis, or possibly mechanical thrombectomy by using a thrombus-removal device.
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PMID:[Prospects of thrombolytic therapy for acute ischemic stroke]. 1980 99

Previous studies and clinical observations reveal that stroke survivors show the resurgence of the asymmetric tonic neck reflex (ATNR) both in static and dynamic conditions during maximal efforts. This observation may imply more reliance on the brainstem pathways following stroke. However, the effect of ATNR during a dynamic condition that represents more natural movement, such as reaching, has not been studied before. During reaching movements, the application of a robot controlled haptic environment is important to quantify the effect of ATNR following stroke. Therefore, this paper reports the use of a novel setup using the ACT(3D) robotic device to investigate and quantify this reflexive behavior. Our preliminary results demonstrate that the effect of ATNR is significant in the stroke population when abducting the shoulder at 25% of maximum ability. These results show that the ATNR affects reaching distance especially when shoulder loading in abduction is required. In conclusion, these preliminary results provide evidence that the effect of ATNR in stroke subjects during reaching task can be quantified by using a novel 3-D robotic setup.
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PMID:The effects of asymmetric tonic neck reflex during reaching movement following stroke: preliminary results. 1996 37

After the success of the 1995 National Institutes of Neurological Disorders and Stroke (NINDS) study using intravenous (i.v.) recombinant tissue plasminogen activator (rt-PA, alteplase) within 3 hours in acute stroke, this therapy was approved worldwide and has been a standard therapy for acute stroke patients. In Japan, IV alteplase at a dose of 0.6 mg/kg was approved in 2005 after a multicenter study using this low dose of alteplase (Japan Alteplase Clinical Trial [J-ACT]). IV rt-PA can drastically improve stroke outcomes. However, more than half of treated patients are not independent in the chronic stage. In addition, the therapeutic time window was so limited that many stroke patients do not have a chance to receive the therapy. In 2008, European Cooperative Acute Stroke Study III showed that IV rt-PA administered between 3 and 4.5 hours after stroke onset significantly improved clinical outcomes in stroke patients; the success resulted in the renewal of recommendation in guidelines in Europe, Canada, and the United States. Several therapeutic strategies, including endovascular therapy, sonothrombolysis, and neuroprotective therapy, may improve the efficacy of IV rt-PA.
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PMID:[Intravenous rt-PA therapy for acute ischemic stroke: efficacy and limitations]. 2003 Feb 14

This study sought to test the hypothesis that orthostasis-induced cerebral hypoperfusion would be less severe in physically active elderly humans (ACT group) than in sedentary elderly humans (SED group). The peak O(2) uptake of 10 SED (67.1 +/- 1.4 yr) and 9 ACT (68.0 +/- 1.1 yr) volunteers was determined by a graded cycling exercise test (22.1 +/- 1.2 vs 35.8 +/- 1.3 ml.min(-1).kg(-1), P < 0.01). Baseline mean arterial pressure (MAP; tonometry) and middle cerebral arterial blood flow velocity (V(MCA); transcranial Doppler) were similar between the groups (SED vs. ACT group: 91 +/- 3 vs. 87 +/- 3 mmHg and 54.9 +/- 2.3 vs. 57.8 +/- 3.2 cm/s, respectively), whereas heart rate was higher and stroke volume (bioimpedance) was smaller in the SED group than in the ACT group. Central hypovolemia during graded lower body negative pressure (LBNP) was larger (P < 0.01) in the ACT group than in the SED group. However, the slope of V(MCA)/LBNP was smaller (P < 0.05) in the ACT group (0.159 +/- 0.016 cm/s/Torr) than in the SED group (0.211 +/- 0.008 cm/s/Torr). During LBNP, the SED group had a greater augmentation of cerebral vasomotor tone (P < 0.05) and hypocapnia (P < 0.001) compared with the ACT group. Baseline MAP variability and V(MCA) variability were significantly smaller in the SED group than in the ACT group, i.e., 0.49 +/- 0.07 vs. 1.04 +/- 0.16 (mmHg)(2) and 1.06 +/- 0.19 vs. 4.24 +/- 1.59 (cm/s)(2), respectively. However, transfer function gain, coherence, and phase between MAP and V(MCA) signals (Welch spectral estimator) from 0.08-0.18 Hz were not different between SED (1.41 +/- 0.18 cm.s(-1).mmHg(-1), 0.63 +/- 0.06 units, and 38.03 +/- 6.57 degrees ) and ACT (1.65 +/- 0.44 cm.s(-1).mmHg(-1), 0.56 +/- 0.05 units, and 48.55 +/- 11.84 degrees ) groups. We conclude that a physically active lifestyle improves the intrinsic mechanism of cerebral autoregulation and helps mitigate cerebral hypoperfusion during central hypovolemia in healthy elderly adults.
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PMID:Chronic physical activity mitigates cerebral hypoperfusion during central hypovolemia in elderly humans. 2004 43


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