Publications by authors named "Fabio Iuji Yamamoto"

Background: Despite enormous advances in the diagnosis and treatment of ischemic stroke over the past decades, the extent of "standard" investigation to define its causes is heterogeneous. Young patients often undergo a myriad of diagnostic tests in developed countries, but the cost-effectiveness of this approach is uncertain.

Objectives: Our main goal was to compare the frequencies of ischemic stroke of undetermined and determined etiologies in young patients with "complete" or "incomplete" investigation according to either a stepwise or an extensive protocol.

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Stroke affects mainly people aged over 65 years, and atherosclerosis predominates as the main etiopathogenic factor in ischemic stroke (IS). On the other hand, cardiac embolism and arterial dissection are the most frequent causes of IS in patients aged less than 45 years. However, inappropriate control of traditional vascular risk factors in young people may be causing a significant increase of atherosclerosis-related IS in this population.

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Context: The aim of this paper was to report on the characteristics that aid in establishing the diagnosis of basilar artery occlusive disease (BAOD) among patients with hemiparesis and few or minor symptoms of vertebrobasilar disease.

Case Report: This report describes two cases in a public university hospital in São Paulo, Brazil. We present clinical and imaging findings from two patients with hemiparesis and severe BAOD, but without clinically relevant carotid artery disease (CAD).

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Early after stroke, there is loss of intracortical facilitation (ICF) and increase in short-interval intracortical inhibition (SICI) in the primary motor cortex (M1) contralateral to a cerebellar infarct. Our goal was to investigate intracortical M1 function in the chronic stage following cerebellar infarcts (>4 months). We measured resting motor threshold (rMT), SICI, ICF, and ratios between motor-evoked potential amplitudes (MEP) and supramaximal M response amplitudes (MEP/M; %), after transcranial magnetic stimulation was applied to the M1 contralateral (M1(contralesional)) and ipsilateral (M1(ipsilesional)) to the cerebellar infarct in patients and to both M1s of healthy age-matched volunteers.

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Introduction: Purposes of this study were: evaluate complications and length of stay of patients admitted with diagnosis of ischemic stroke (IS) in the acute or subacute phase, in a general Neurology ward in São paulo, Brazil; investigate the influence of age, risk factors for vascular disease, arterial territory and etiology.

Methods: Data from 191 IS patients were collected prospectively.

Results: Fifty-one patients (26.

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Spontaneous cervical arterial dissection (SCAD) is a non-traumatic tear or disruption in the wall of the internal carotid arteries or the vertebral arteries. It accounts for about 25% of strokes in patients aged under 45 years. Awareness of its clinical features and advances in imaging over the last two decades have contributed to earlier identification of this condition.

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Objective: To describe characteristics and provision of care for patients admitted with cerebrovascular disorders (CVD), focusing on ischemic stroke (IS), in a large, public, academic hospital in São Paulo, Brazil.

Method: We retrieved information about 357 patients with CVD admitted to the Neurology Emergency Department (NED) and Neurology Ward (NW) of our institution. We described patient characteristics and management of IS in NED and in NW.

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Basilar artery (BA) dissecting aneurysms pose difficulties to treatment because both bleeding and thrombosis can happen in the same patient, clinical course is unpredictable and high morbidity is usual. We report the case of a 37-year-old woman with a BA aneurysm probably caused by arterial dissection, presenting embolic and hemorrhagic complications. The aneurysm was submitted to endovascular treatment with stenting and coil embolization.

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Purpose: It has been suggested that mitochondrial disease may be responsible for a substantial proportion of strokes of indetermined origin. We have preliminarily screened for MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes) mutations in young patients with cryptogenic strokes.

Method: The mitochondrial mutations A3243G and T3271C were investigated in 38 subjects aged less than 46 years.

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The persistent hypoglossal artery (PHA) is the second most common persistent embryological carotid-basilar connection and usually represents an incidental finding in cerebral arteriograms. The hypoglossal artery connects the primordial carotid artery with the longitudinal neural arteries, which later form the basilar artery. The PHA leaves the internal carotid artery as an extracranial branch, enters the skull through the anterior condyloid foramen, the hypoglossal canal and joins the caudal portion of the basilar artery.

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Intravenous thrombolysis is an important procedure that has significant impact on ischemic stroke prognosis. However, intracranial hemorrhage (ICH) is a feared complication of this procedure. It has been suggested that cerebral microbleeds (CMBs) may increase the risk of ICH after thrombolysis.

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Purpose: We preliminarily investigated the relevance of performing digital subtraction angiography (DSA) in addition to magnetic resonance angiography (MRA) in definition of ischemic stroke etiology in young patients.

Method: DSAs and MRAs from 17 young patients with nonlacunar ischemic stroke were blindly analyzed and their impact on stroke management was evaluated.

Results: Etiologies were the same considering results of either DSA or MRA in 12/17 cases.

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Objective: To investigate the correlation between facial sensory abnormalities and lesional topography in eight patients with lateral medullary infarcts (LMIs).

Method: We reviewed eight sequential cases of LMIs admitted to the Neurology Division of Hospital das Clínicas/São Paulo University between July, 2001 and August, 2002 except for one patient who had admitted in 1996 and was still followed in 2002. All patients were submitted to conventional brain MRI including axial T1-, T2-weighted and Fluid attenuated inversion-recovery (FLAIR) sequences.

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We report the case of a 36 year-old woman who presented occlusion of a basilar artery fusiform aneurysm (FA) associated with pontine infarction, and two episodes of subarachnoid hemorrhage possibly due to arterial dissection. She also had asymptomatic FAs in the right middle cerebral and left internal carotid arteries. Over 5 years, lesions suggestive of fibromuscular dysplasia in the right vertebral artery and occlusion of the left vertebral artery were observed.

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Objective: To report a Brazilian series of spontaneous cervical arterial dissections, risk factors, warning symptoms, clinical manifestations, diagnostic tests, treatment and prognosis.

Method: We performed the retrospective analysis of clinical and neuroradiological records (MRI, A-MRI and Angiography) of patients with this diagnosis who were evaluated in a tertiary hospital for the period of 1997-2003.

Results: 48 patients (24 men) with median age 37.

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Subclavian steal syndrome refers to the association of neurological symptoms related to vertebrobasilar insufficiency and the phenomenon of subclavian steal. We report the case of a 63 year-old male patient that presented subclavian steal syndrome and severe proximal (80%) stenosis of the left subclavian artery. The patient was submitted to percutaneous transluminal angioplasty and stenting on the left SA.

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