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Biomedical subjects

Hiroshi Moriwaki

Publications and source records attributed to Hiroshi Moriwaki.

At least 19 recordsLinked to original sources
PubMed2006

Early CT findings in unknown-onset and wake-up strokes.

BACKGROUND: Approximately one quarter of the acute ischemic stroke patients notice the event at awakening. Such patients with stroke at awakening are usually excluded from thrombolysis, since the time of stroke onset cannot be definitely identified. We compared the hyperacute CT findings of awakening stroke patients with those of stroke patients with known onset to assess whether the time of stroke onset is shortly before awakening. METHODS: Subjects were cardioembolic stroke patients who were consecutively admitted to our department within 3 h after the recognition of stroke during the period between January 2000 and March 2003. The patients were classified into three groups: group A with stroke of known onset, group B with stroke at awakening, and group C with stroke of unknown onset due to lack of a witness. The clinical and CT findings in each group were compared. RESULTS: A total of 81 patients fulfilled the study criteria. There were 46 patients in group A, 17 patients in group B, and 18 patients in group C. There was no significant difference in CT findings between groups A and B. In group C, however, definite hypodense areas were more commonly found than in group A (56 vs. 0%; p<0.001) or in group B (56 vs. 11%; p=0.012). CONCLUSION: Based on our CT findings, stroke at awakening seems to be developing shortly before in a large subset of patients, making them potential candidates for acute stroke therapies.

Adult↗
PubMed2005

Sonochemical decomposition of perfluorooctane sulfonate and perfluorooctanoic acid.

Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are shown to be globally distributed, environmentally persistent, and bioaccumulative. Although the toxicities of these compounds were reported, the cleanup procedure from the environment is not developed because of their inertness. In this report the sonochemical degradations of PFOS and PFOA to the products through the fission of the perfluorocarbon chains were observed and the half-life times of the PFOS and PFOA degradations under an argon atmosphere determined to be 43 and 22 min, respectively. The shortening of perfluorocarbon chain of PFOS and PFOA leads to the lowering of the toxicity in view of the decrease of the persistence, and the technique would contribute to the remediation of the environmental pollution by these compounds.

Alkanesulfonic Acids↗
PubMed2005

Mechanisms of bihemispheric brain infarctions in the anterior circulation on diffusion-weighted images.

BACKGROUND AND PURPOSE: Multiple acute brain infarctions in both cerebral hemispheres usually suggest an embolic mechanism, particularly one of aortic or cardiac origin. The purpose of this study was to clarify the etiologic mechanisms and topographic features of bihemispheric infarctions depicted on diffusion-weighted imaging (DWI). METHODS: Among 411 consecutive patients with ischemic stroke who underwent MR imaging in the acute phase, DWI showed bilateral infarctions in 19 (4.6%). In these patients, we analyzed the presence of carotid, aortic or cardiac embolic sources by using ultrasonography, cerebral angiography, and/or transesophageal echocardiography and evaluated the size and topographic distribution of the lesions. We assessed intracranial cross-flow through the anterior communicating artery, mainly on the basis of the anatomic information obtained from angiography or MR angiography. RESULTS: Bilateral lesions were derived from cardiac and/or aortic embolic sources in 16 (84%) of 19 patients and appeared to originate from unilateral carotid diseases in three (16%). In nine (82%) of 11 patients with cardiac embolic sources, at least one large territorial or subcortical lesion was found in either hemisphere, whereas in all eight patients without a cardiac embolic source, the lesions were small and disseminated bilaterally. CONCLUSION: Unilateral carotid lesions can cause bihemispheric infarctions through cross-flow in the anterior communicating artery. On DWI, small bihemispheric, disseminated lesions strongly suggest an artery-to-artery embolism. In such cases, aortic and carotid lesions should be assessed as potential embolic sources.

Aged↗
PubMed2005

[Incongruous homonymous quadrantanopia due to suprasellar calcificated lesions].

A 53 year-old woman with a history of tuberculous meningitis at 3 years of age incidentally found a right incongruous homonymous quadrantanopia in ophthalmologic check-up. On magnetic resonance imaging and helical computed tomography, the left optic tract was obscured by suprasellar calcified lesions. The left internal carotid artery was diffusely narrowed and occluded at its terminal portion as demonstrated by cerebral angiography. The calcificated lesions were diagnosed to derive from old tuberculous meningitis on the basis of her history, their location and the association of vascular occlusive changes. Incongruous homonymous hemianopsia due to optic tract damage is usually caused by tumor or aneurysm. Its occurrence by calcified inflammatory lesions has never been reported previously. The present case is considered of value in this respect.

Calcinosis↗
PubMed2004

Simultaneous determination of 2-phenylbenzotriazole-type mutagens, PBTA-1 through -8, in river water by liquid chromatography-tandem mass spectrometry.

We describe a method for the simultaneous determination of eight kinds of phenylbenzotriazole-type mutagens (PBTA-1, -2, -3, -4, -5, -6, -7 and -8) in river water based on liquid chromatography-tandem mass spectrometry (LC/MS/MS). The application of dopant-assisted atmospheric pressure photoionization (APPI) for the detection of the PBTAs was studied. The APPI technique provided higher PBTA signal intensities than those obtained with an electrospray ionization (ESI) source, and the APPI method was used for the determination of the PBTAs. A solid-phase extraction procedure was used for the extractions of PBTA-1 through -8 from river water. The procedure was rapid and the relative standard deviations were below 15%. The detection limits of PBTA-1 through -8 in river water using the proposed method were found to range from 0.04 to 0.5 ng L(-1) and PBTAs were successfully detected in river water at sub-ng L(-1) levels.

Chromatography, Liquid↗
PubMed2004

Relationship between cognitive function and regional cerebral blood flow in different types of dementia.

PURPOSE: We assessed relationships between cognitive impairment and regional cerebral blood flow (rCBF) in the different types of dementia. SUBJECTS AND METHODS: Subjects, who included 27 with Alzheimer's disease (AD), seven with frontotemporal dementia (FTD), six with vascular dementia (VaD), and 12 normal controls, were evaluated using the Mini-mental State (MMS), Kana-hiroi Test, an auditory verbal learning test (AVLT), a word fluency test (WFT) and Raven's Coloured Progressive Matrices (RCPM). The rCBF was measured using a three-dimensional stereotaxic ROI template method (3DSRT). RESULTS: In all dementia types, left superior frontal hypoperfusion was demonstrated. In AD and VaD significant CBF reduction also was seen in both angular, temporal, occipital, and precentral, both hippocampi, thalami, and pericallosal regions, and the left lenticular nucleus. MMS, Kana-hiroi Test, and AVLT scores correlated with CBF in all regions. WFT scores were correlated highly with CBF in the left side in frontal, temporal, and angular regions and right and left lenticular nuclei, thalami, and pericallosal regions. RCPM scores correlated with CBF in posterior regions. CONCLUSION: Close coupling was evident between reduced rCBF and cognitive dysfunction in patients with dementia. Use of neuropsychologic tests and rCBF determinations in combination should enhance diagnostic accuracy.

Aged↗
PubMed2004

Circulating CD34-positive cells provide an index of cerebrovascular function.

BACKGROUND: Increasing evidence points to a role for circulating endothelial progenitor cells, including populations of CD34- and CD133-positive cells present in peripheral blood, in maintenance of the vasculature and neovascularization. Immature populations, including CD34-positive cells, have been shown to contribute to vascular homeostasis, not only as a pool of endothelial progenitor cells but also as a source of growth/angiogenesis factors at ischemic loci. We hypothesized that diminished numbers of circulating immature cells might impair such physiological and reparative processes, potentially contributing to cerebrovascular dysfunction. METHODS AND RESULTS: The level of circulating immature cells, CD34-, CD133-, CD117-, and CD135-positive cells, in patients with a history of atherothrombotic cerebral ischemic events was analyzed to assess possible correlations with the degree of carotid atherosclerosis and number of cerebral infarctions. There was a strong inverse correlation between numbers of circulating CD34- and CD133-positive cells and cerebral infarction. In contrast, there was no correlation between the degree of atherosclerosis and populations of circulating immature cells. Analysis of patients with cerebral artery occlusion revealed a significant positive correlation between circulating CD34- and CD133-positive cells and regional blood flow in areas of chronic hypoperfusion. CONCLUSIONS: These results suggest a possible contribution of circulating CD34- and CD133-positive cells in maintenance of the cerebral circulation in settings of ischemic stress. Our data demonstrate the utility of a simple and precise method to quantify circulating CD34-positive cells, the latter providing a marker of cerebrovascular function.

AC133 Antigen↗
PubMed2004

Evaluation of the use of a standard input function for compartment analysis of [123I]iomazenil data: factors influencing the quantitative results.

Adoption of standard input function (SIF) has been proposed for kinetic analysis of receptor binding potential (BP), instead of invasive frequent arterial samplings. The purpose of this study was to assess the SIF method in quantitative analysis of [123I]iomazenil (IMZ), a central benzodiazepine antagonist, for SPECT. SPECT studies were performed on 10 patients with cerebrovascular disease or Alzheimer disease. Intermittent dynamic SPECT scans were performed from 0 to 201 min after IMZ-injection. BPs calculated from SIFs obtained from normal volunteers (BPs) were compared with those of individual arterial samplings (BPo). Good correlations were shown between BP(o)s and BP(s)s in the 9 subjects, but maximum BP(s)s were four times larger than the corresponding BP(o)s in one case. There were no abnormal laboratory data in this patient, but the relative arterial input count in the late period was higher than the SIF. Simulation studies with modified input functions revealed that height in the late period can produce significant errors in estimated BPs. These results suggested that the simplified method with one-point arterial sampling and SIF can not be applied clinically. One additional arterial sampling in the late period may be useful.

Adolescent↗
PubMed2004

Usefulness of a cube-copying test in outpatients with dementia.

OBJECTIVE: To clarify whether a quantitatively scored cube-copying test could rapidly assess dementia patients, predicting thier performance in cognitive tests. METHODS: Subjects were 171 outpatients with amnesia who were including 92 with Alzheimer's disease (AD); 59 vascular dementia (VD); 17 frontotemporal dementia (FTD); and three lewy body disease (DLB) and 32 normal healthy subjects. Subjects asked to copy a perspective drawing of a cube. Points of connection and plane-orientation errors were scored using Maeshima's method. The Mini-Mental State Examination (MMSE), an auditory verbal learning test (AVLT), a word fluency test and Raven's Coloured Progressive Matrices (RCPM) were administered. Age, clinical disease severity, symptom duration, specific diagnosis and neuropsychological scores were evaluated for relationships with constructional ability. RESULTS: The cube-copying test showed errors in most dementia patients and 11 of 32 normal subjects. Only three patients each with AD and VD copied correctly, but 11 patients with 17 FTD drew the cube correctly. Numbers of connections completed and plane-orientation errors correlated significantly with MMSE, AVLT, word fluency and RCPM scores. CONCLUSION: The cube-copying test is useful for routine clinical dementia screening, however the test examines only one aspect of cognitive function. While not an alternative to conventional neuropsychological examinations, quantitatively scored cube copying can provide a rough estimate of cognitive dysfunction in dementia patients.

Aged↗
PubMed2004

Determination of polycyclic aromatic hydrocarbons in sediment by liquid chromatography-atmospheric pressure photoionization-mass spectrometry.

We describe a method for the simultaneous determination of 12 kinds of polycyclic aromatic hydrocarbons (PAHs) in sediment based on liquid chromatography-atmospheric pressure photoionization-mass spectrometry (LC/APPI/MS). The method consists of PAH extractions by ultrasonics, clean-up by a solid-phase extraction procedure and determination by LC/APPI/MS. The limits of the determination for PAHs in sediment using the proposed method ranged from 0.06 to 0.9 mg/kg. PAHs were detected by this method in sediment samples on the mg/kg level.

Journal Article↗
PubMed2004

A small pulmonary arteriovenous malformation as a cause of recurrent brain embolism.

We report a case of recurrent paradoxical brain embolism mediated through a small pulmonary arteriovenous malformation (PAVM) with a 1.8-mm-diameter feeding artery. In this case, the further recurrent stroke was prevented successfully by PAVM embolization. Although embolization therapy is currently recommended only for PAVMs with feeding arteries greater than 3 mm in diameter, the therapy may be needed also in the smaller PAVMs.

Aged↗
PubMed2004

[Acute brain infarction clearly demonstrated by using the three-dimensional stereotactic surface projections (3D-SSP) of 99mTc-HMPAO SPECT].

We report a 66-year-old ambidextrous man who suddenly developed aphasia seven days after coronary artery bypass grafting surgery. CT scan performed 30 minutes after onset failed to depict acute ischemic lesion. MR imaging could not be performed because of intrathoracic wires. An emergent angiogram demonstrated filling defect in the right precentral artery territory. Transaxial images of 99mTc-HMPAO SPECT showed hypoperfusion areas in the right frontal and left temporo-parietal regions. Using the three-dimensional stereotactic surface projections (3D-SSP) of 99mTc-HMPAO SPECT, we could clearly detect a sharply demarcated ischemic area which was later confirmed to be an infracted lesion in the follow-up CT. 3D-SSP, thus, appears to be useful for identifying acute infarction in such cases that MRI is impermissible.

Acute Disease↗
PubMed2003

Cerebral hemodynamic evaluation using perfusion-weighted magnetic resonance imaging: comparison with positron emission tomography values in chronic occlusive carotid disease.

BACKGROUND AND PURPOSE: Perfusion-weighted magnetic resonance imaging (PWI) is a reliable and semiquantitative method for estimating cerebral hemodynamics. We sought to evaluate the potential of PWI for assessing cerebral blood flow (CBF) and metabolism compared with positron emission tomography (PET) in patients with chronic occlusive carotid disease. METHODS: In 24 patients with chronic unilateral occlusive carotid disease, time-to-peak (TTP) delay (TTP-D) measured by PWI was compared with CBF, cerebral blood volume (CBV), and oxygen extraction fraction (OEF) obtained by PET. TTP indicates the time from the start of PWI to the bolus peak. TTP-D indicates the difference in TTP values between the occlusive and contralateral hemispheres. TTP-D was compared between patients with normal and reduced CBF/CBV and also between patients with normal and elevated OEF. RESULTS: TTP-D in patients with reduced CBF/CBV was significantly longer than that in patients with normal CBF/CBV (3.4+/-1.8 versus 1.4+/-0.7 seconds; P<0.001). In the patients with reduced CBF/CBV, TTP-D correlated with OEF significantly (r=0.710, P<0.0001). TTP-D in patients with elevated OEF was significantly longer than that in patients with normal OEF (4.8+/-2.2 versus 2.0+/-0.9 seconds; P<0.01). In all 5 patients with TTP-D >or=4 seconds, OEF was elevated markedly. CONCLUSIONS: TTP-D >or=4 seconds is considered to indicate a high risk of hemodynamic failure. The measurement of TTP-D by PWI appears to provide important clinical information for evaluating cerebral hemodynamics in chronic occlusive carotid disease.

Aged↗