Biomedical subjects

Masaaki Uno

Publications and source records attributed to Masaaki Uno.

At least 19 recordsLinked to original sources

PubMed2006

Effect of additional auditory and visual stimuli on continuous performance test (noise-generated CPT) in AD/HD children -- usefulness of noise-generated CPT.

The continuous performance test (CPT) is designed to measure sustained attention quantitatively. Several CPTs are used clinically. We have made changes to the conventional type of visual CPT, by displaying auditory and visual noise along with target or non-target stimuli. By influencing the recognition of the subjects in this way, the changes were intended to increase the sensitivity of detection of inattention and impulsiveness, to make CPT more useful for diagnosis, and to examine the effect of noise on AD/HD children during CPT performance. Its usefulness for AD/HD diagnosis and the reaction of AD/HD children to noise were examined using newly developed computer software. Using this CPT analysis, a significant difference was observed in all measurements, except mean reaction time, between the control and AD/HD groups, showing that it was useful as a supplementary diagnostic method for AD/HD, and was more useful in the younger age group than in the older age group, as the same for conventional CPTs. As compared to no-noise sessions, commission and omission errors both increased significantly in auditory and visual noise sessions. Thus, analyzing the changes in measurements during noise sessions will improve the diagnosis of inattention and combined AD/HD subtypes. Furthermore, it was suggested that analysis of the effects of noise on AD/HD children will benefit their handling in an educational environment. Since omission errors were decreased in AD/HD children by noise during the CPT performance as compared to the control group, noise may induce attention in AD/HD children. The present study presents new findings on the responses to noise of AD/HD children during the CPT.

Acoustic Stimulation↗

PubMed2006

Change of diffusion anisotropy in patients with acute cerebral infarction using statistical parametric analysis.

PURPOSE: We conducted statistical parametric comparison of fractional anisotropy (FA) images and quantified FA values to determine whether significant change occurs in the ischemic region. MATERIALS AND METHODS: The subjects were 20 patients seen within 24 h after onset of ischemia. For statistical comparison of FA images, a sample FA image was coordinated by the Talairach template, and each FA map was normalized. Statistical comparison was conducted using SPM99. Regions of interest were set in the same region on apparent diffusion coefficient (ADC) and FA maps, the region being consistent with the hyperintense region on diffusion-weighted images (DWIs). The contralateral region was also measured to obtain asymmetry ratios of ADC and FA. RESULTS: Regions with areas of statistical significance on FA images were found only in the white matter of three patients, although the regions were smaller than hyperintense regions on DWIs. The mean ADC and FA ratios were 0.64 +/- 0.16 and 0.93 +/- 0.09, respectively, and the degree of FA change was less than that of the ADC change. Significant change in diffusion anisotropy was limited to the severely infarcted core of the white matter. CONCLUSION: We believe statistical comparison of FA maps to be useful for detecting different regions of diffusion anisotropy.

Acute Disease↗

PubMed2006

Hemichorea due to hemodynamic ischemia associated with extracranial carotid artery stenosis. Report of two cases.

In this paper the authors describe two patients with recurrent hemiparesis and limb shaking that gradually progressed to hemichorea. Cerebral angiography confirmed severe unilateral internal carotid artery stenosis (95%) contralateral to the hemichorea. The cerebral blood flow, assessed using N-isopropyl-p-(iodine-123) iodoamphetamine single-photon emission computed tomography (SPECT), disclosed markedly decreased vascular reserves in both patients. After carotid endarterectomy was performed, the hemichorea gradually subsided and SPECT confirmed increased cerebral perfusion. The results in these cases indicate that surgical revascularization is effective for hemichorea due to cerebral ischemia with reduced vascular reserve.

Aged↗

PubMed2005

Inhibition of brain damage by edaravone, a free radical scavenger, can be monitored by plasma biomarkers that detect oxidative and astrocyte damage in patients with acute cerebral infarction.

We assess the availability of plasma biomarkers to monitor the brain damage and the therapeutic efficacy of edaravone. The study consisted of 51 patients with ischemic cerebral infarcts. They were divided into 2 groups: GI (n = 24) had cortical lesions, and GII (n = 27) had lesions in the basal ganglia or brain stem. Edaravone was administered to 27 randomly selected patients (GIa, n = 13; GIIa, n = 14) and its efficacy was studied by comparing their plasma OxLDL, S-100B, and MnSOD levels to those in patients without edaravone (GIb, n = 11, GIIb, n = 13). Three days after the start of edaravone, plasma OxLDL was significantly lower in GIa than GIb patients (0.177 +/- 0.024 ng/microg apoB vs 0.219 +/- 0.026, P < 0.05). In GIIa patients, pre- and posttreatment plasma OxLDL was not significantly different (0.156 +/- 0.013 vs 0.152 +/- 0.020). In GIa patients, S-100B and MnSOD were significantly lower than in GIb patients (P < 0.05). The neurological condition at the time of discharge had recovered in GIa but not GIb patients. Ours is the first evidence to confirm the efficacy of edaravone by plasma biomarkers. In patients with cortical infarcts, edaravone reduced oxidative damage, thereby limiting the degree of brain damage.

Adult↗

PubMed2005

Elevation of plasma oxidized LDL in acute stroke patients is associated with ischemic lesions depicted by DWI and predictive of infarct enlargement.

Oxidized low-density lipoprotein (OxLDL) plays a major role in atherosclerosis. We undertook the present study to clarify the relationship between plasma OxLDL and the ischemic volume. We used ELISA to determine plasma OxLDL levels, and performed diffusion- and perfusion-weighted MRI (DWI, PWI) to measure the ischemic volume in 44 ischemic stroke patients. Based on the location of the ischemic lesion, they were divided into three groups: Group I (GI, n = 21) had cortical lesions, Group II (GII, n = 17) had lesions in the basal ganglia or brain stem, and Group III (GIII, n = 6) had massive lesions that involved one entire hemisphere. In GI, but not GII and GIII, plasma OxLDL was significantly higher than in 19 age-matched controls (p < 0.01) and was significantly correlated with the initial ischemic volume visualized on DWI (p = 0.01), PWI (p < 0.01), and the DWI-PWI mismatch (p < 0.05). A persistent increase in plasma OxLDL was associated with enlargement of the ischemic lesion in the early phase after the insult. These findings suggest that elevated plasma OxLDL levels are associated with moderate ischemic damage in patients with cortical lesions (GI), but not those with massive hemispheric lesions (GIII), which may be irreversible. In addition, elevated plasma OxLDL may represent a predictor of enlargement of the ischemic lesion.

Adult↗

PubMed2005

Anaplastic ganglioglioma of the cerebellopontine angle. Case report.

A 64-year-old woman presented with a rare anaplastic ganglioglioma in the right cerebellopontine angle manifesting as dizziness persisting for 2 weeks. Preoperative magnetic resonance (MR) imaging revealed a partially enhanced cystic lesion of the right cerebellopontine angle. The tumor was subtotally removed through a right lateral suboccipital craniectomy. The tumor was thought to originate from the brain stem with exophytic growth into the right cerebellopontine angle. Histological examination showed neoplastic ganglional and glial cells with anaplastic features such as mitosis, pleomorphism, and endothelial proliferation. The MIB-1 labeling index of the glial components was 40% to 60%. The diagnosis was anaplastic ganglioglioma (World Health Organization grade IV). She received postoperative radiotherapy but died of respiratory failure with tumor recurrence 11 months after the operation. Gangliogliomas usually have a good prognosis. Histological features of anaplasia and a high MIB-1 labeling index may be predictive of a poor clinical outcome.

Cerebellar Neoplasms↗

PubMed2005

Contribution of an imbalance between oxidant-antioxidant systems to plaque vulnerability in patients with carotid artery stenosis.

OBJECT: Reactive species of oxygen and nitrogen mediate the oxidative modification of low-density lipoprotein (LDL). Oxidation of LDL is inhibited by endogenous radical scavenging enzymes such as manganese superoxide dismutase (SOD) and Cu-ZnSOD that catalyze dismutation of oxygen to H2O2. Low-molecular antioxidants such as uric acid regulate the inactivation that appears to be linked to an increase in peroxynitrite resulting in oxidized LDL (OxLDL) elevation. The authors evaluated whether a focal imbalance between pro- and antioxidant systems induces plaque vulnerability in patients with carotid artery (CA) stenosis. METHODS: Carotid artery plaques obtained in 35 patients who had undergone carotid endarterectomy were classified as vulnerable or stable based on histopathological findings. In vulnerable plaques, OxLDL, measured using enzyme-linked immunosorbent assay, was significantly higher (p < 0.01) and SOD activity significantly lower than in stable plaques (p < 0.05). The plaque and plasma OxLDL levels were inversely correlated with plaque SOD activity (p < 0.01). The physiological uric acid level in all plaques was one fourth to one eighth of that in plasma and appeared to be unable to protect Cu-ZnSOD from degradation by H2O2. Immunohistochemical analysis showed increased peroxynitrite and OxLDL in vulnerable plaques. There was a significant correlation between plaque and plasma OxLDL levels (p < 0.01). CONCLUSIONS: Analysis of the results suggests that a focal imbalance between pro- and antioxidant defense systems in patients with CA plaques induces an increase in plaque OxLDL levels and consequent plaque instability, contributing to high levels of plasma OxLDL.

Aged↗

PubMed2004

Peripheral oxidative biomarkers constitute a valuable indicator of the severity of oxidative brain damage in acute cerebral infarction.

Oxidative stress contributes to post-ischemic brain damage. We assessed the correlation between plasma 8-hydroxy-2'-deoxyguanosine (8-OHdG), as a marker of oxidative DNA damage, and progressive brain damage in rats subjected to transient or permanent ischemia. Male Wistar rats were subjected to permanent- and 0.5-, 1-, 2-h middle cerebral artery occlusion (MCAO). At various times thereafter, the infarct volume, 8-OHdG levels in plasma and brain tissue, DNA fragmentation, and immunohistochemical observations on their brains were recorded and compared. At 12 h after 2-h MCAO-reperfusion, the cortical infarct volume was increased; it peaked at 24 h. DNA degeneration expanded from the caudate putamen into the cortical region at 12 h. 8-OHdG-containing cells in the cortical infarct zone were observed at 12 h, the number of 8-OHdG-positive cells was highest at 24 h and they co-localized with DNA single-strand breaks. Plasma 8-OHdG significantly increased at 12 h, and peaked at 24 h after reperfusion (1.1+/-0.7 ng/ml (mean+/-S.D.); controls 0.3+/-0.1; p<0.01). This increase was in step with increased infarct volume, DNA degradation, and reflected immunohistochemical findings in the cortical region but not the caudate putamen. In the permanent MCAO model, plasma 8-OHdG levels were associated with the brain contents of 8-OHdG. Plasma 8-OHdG and the cortical infarct volume were lower in the 0.5- and 1-h than the 2-h MCAO model. Our findings suggest that 8-OHdG as a peripheral biomarker may be an indicator of oxidative brain damage in acute cerebral infarction.

8-Hydroxy-2'-Deoxyguanosine↗

PubMed2004

Correlation between flow-sensitive alternating inversion recovery perfusion imaging with different inversion times and cerebral flow reserve evaluated by single-photon-emission computed tomography.

The purpose of this study was to evaluate the effect of different inversion times (TIs) on flow-sensitive alternating inversion recovery (FAIR) perfusion imaging and compare them with the cerebral blood flow reserve evaluated by acetazolamide challenge using single-photon-emission computed tomography (SPECT). The subjects were nine patients with unilateral obstruction of the internal carotid artery. The signal ratio (SR16/8) of two images with different TIs (1,600 ms and 800 ms) was calculated, and the cerebral blood flow reserve (CFR) was evaluated by the increase in the ratio of cerebral perfusion after administration of acetazolamide in the SPECT study. A reversed linear correlation ( r=0.75) was found between SR and CFR, indicating that differences of FAIR images with changes of TI will be affected by cerebral flow reserve.

Acetazolamide↗

PubMed2004

Does multimodality therapy of arteriovenous malformations improve patient outcome?

The strategy for treating arteriovenous malformations (AVMs) has undergone changes and long-term follow-up results remain unclear. To compare the outcomes of different treatment strategies, we divided 112 patients with 113 AVMs into groups with hemorrhagic (n = 71, 62.8%) and nonhemorrhagic (n = 42, 37.2%) AVMs and subdivided these according to the period in which they were treated (before/after 1990). In the more recent period, treatment more frequently involved the use of the gamma-knife and microembolization to the AVM as well as combination therapy. Long-term follow-up showed that the complication rate was lower and the Rankin scale better, in the more recently treated group. Based on our findings we suggest that AVMs should be treated aggressively using a multimodality strategy.

Adolescent↗

PubMed2004

Detection of enlarged cortical vein by magnetic resonance imaging contributes to early diagnosis and better outcome for patients with anterior cranial fossa dural arteriovenous fistula.

Twelve patients (10 men, 2 women) with anterior cranial fossa dural arteriovenous fistula (AVF) were treated at our institute between January 1976 and March 2002. Intracranial hemorrhage was the presenting symptom in six patients. Magnetic resonance (MR) imaging findings identified abnormal cortical veins as flow voids in four of five patients. Angiography was the basis of the diagnosis in all patients. Surgery was the primary treatment in nine patients. The other three patients refused intervention and managed conservatively. Surgical morbidity was negligible and the treatment outcome was highly dependent on the clinical status at presentation. In contrast to the reported high incidence of intracranial hemorrhage in patients with dural AVF in the anterior cranial fossa, only half of our study population presented with hemorrhage. Enlarged cortical veins in the frontobasal area could be detected as flow voids on MR images. This finding contributed to the early diagnosis and treatment of patients treated at our institution for dural AVF in the anterior cranial fossa, and to the better outcomes we obtained in these patients.

Aged↗

PubMed2004

Ischemic basilar artery dissecting aneurysm treated by stenting only--case report.

A 45-year-old man presented with enlargement of basilar artery dissecting aneurysm 10 months after suffering brain stem infarction. Combined stenting and placement of Guglielmi detachable coils (GDCs) was planned to obliterate the aneurysm sac. Stent deployment was performed but the procedure was halted to avoid overdosing with contrast material. Cerebral angiography 10 days later showed thrombosis of the aneurysm sac and normalization of the blood flow in the basilar artery. The patient has been followed up for 2 years and showed good clinical and angiographic outcome. Stenting results in obliteration of the aneurysm sac, so a two-stage procedure is recommended.

Aortic Dissection↗

PubMed2003

Comparison of FAIR technique with different inversion times and post contrast dynamic perfusion MRI in chronic occlusive cerebrovascular disease.

The purpose of this study was to examine the signal change occurring with different inversion times (TIs) of the flow-sensitive alternating inversion recovery (FAIR) technique and to compare with the perfusion image obtained with Gd-DTPA injection. The subjects were 11 patients with unilateral occlusive cerebrovascular disease. Two FAIR images with different TIs (800 ms and 1600 ms) were measured for each patient and dynamic perfusion MRI was performed to produce four kinds of parameter maps: mean transit time (MTT), time to peak (TTP), relative cerebral blood flow (rCBF) and relative cerebral blood volume (rCBV) maps. Asymmetry ratios (ARs) between the affected and contra-lateral vascular sides were measured in both FAIR images and the four dynamic parameter maps. The AR of the MTT map of the four parameters showed the highest correlation with that of the FAIR images, especially with that of TI = 1600 ms (r = 0.829), and the AR of the rCBV map revealed the worst correlation with the FAIR images. The AR of the FAIR image with TI = 800 ms was less correlated with that of MTT than that with TI = 1600 ms. These results suggested that the signal intensity of the FAIR image was influenced by flow transition time and the change in TI could be used to select the flow with a different transition time. Our study suggested that a longer TI in the FAIR technique might be more useful than a shorter TI for evaluating chronic occlusive cerebrovascular disease in the clinical setting.

Brain↗

PubMed2003

Neurocutaneous melanosis associated with malignant leptomeningeal melanoma in an adult: clinical significance of 5-S-cysteinyldopa in the cerebrospinal fluid---case report.

A 35-year-old male presented with a variant of neurocutaneous melanosis with leptomeningeal malignant melanoma. He had three pigmented nevi from birth. He suffered diplopia followed by headache. T1-weighted magnetic resonance (MR) imaging revealed hydrocephalus and a small linear hyperintense lesion in the right frontal cortex. Several parts of the cortical sulci and the brain surface were slightly enhanced by gadolinium. Ventriculoperitoneal shunting was performed and extensive pigmented leptomeninges were recognized. Open biopsy established the diagnosis of leptomeningeal malignant melanoma. Combined chemoimmunotherapy was repeated every other month with monitoring of the 5-S-cysteinyldopa (5-S-CD) level in the cerebrospinal fluid (CSF). The 5-S-CD level decreased after each treatment, but the basal level steadily increased prior to the next treatment. Two years after the onset, he showed paraplegia caused by an extramedullary mass at the T-6 level. MR imaging showed that melanoma had involved the entire subarachnoid space including the whole spine. He underwent emergent removal of the spinal tumor and showed transient marked improvement. Further intensive chemotherapy was given. However, he died 31 months after the onset of massive proliferation of intracranial leptomeningeal melanoma. Measurement of CSF 5-S-CD levels is valuable for evaluating the therapeutic efficacy and for monitoring the progression of melanoma.

Adult↗

PubMed2002

Oxidized LDL in carotid plaques and plasma associates with plaque instability.

OBJECTIVE: Oxidation of LDL plays a significant pathogenic role in atherosclerosis. In this study, we attempted to clarify the correlation between the morphology of human atherosclerotic plaques and the oxidized LDL (OxLDL) levels in plasma and carotid plaques. METHODS AND RESULTS: OxLDL levels (ng/microg apolipoprotein B) in plasma and carotid plaques from 44 patients undergoing carotid endarterectomy and OxLDL levels in 17 control plasma and 9 normal intima samples were determined by a sandwich ELISA by using specific antibodies against OxLDL (DLH3) and apolipoprotein B. The plaques were immunohistochemically classified as macrophage (Mphi)-rich and Mphi-poor. In paired samples from individual patients, plaque OxLDL was nearly 70 times higher than plasma OxLDL (mean+/-SEM, 11.9+/-1.7 vs 0.18+/-0.01 ng/microg apoB, P<0.0001). The OxLDL level was significantly higher in Mphi-rich- than Mphi-poor plaques (19.6+/-2.8 vs 5.50+/-0.77 ng/microg apoB, P<0.0001) and corresponded with DLH3 antigen positivity of the plaques. In patients with Mphi-rich plaques, plasma OxLDL was significantly higher than in the controls (0.20+/-0.02 vs 0.13+/-0.01 ng/microg apoB, P=0.02). CONCLUSIONS: Our results suggest that LDL undergoes further oxidation in plaques, and that high plasma and plaque levels of OxLDL are correlated with the vulnerability to rupture of atherosclerotic lesions.

Adult↗

PubMed2002

Diffusion-weighted in vivo localized proton MR spectroscopy of human cerebral ischemia and tumor.

The apparent diffusion coefficients (ADCs) of water and brain metabolites were determined by proton MR spectroscopy on a clinical MR scanner for healthy volunteers and for pathological changes in cases of acute cerebral infarction and brain tumor. The ADCs of N-acetyl aspartate (NAA) and creatines in tissue involved in acute infarction were decreased compared to normal control values, while in tumors they showed increased values. Since NAA is a neuronal marker, these findings suggest that neuronal cell viscosity changes according to the pathological status of the tissue. The lactate ADC was significantly larger than the values for other major metabolites in cases of ischemia and tumor, suggesting that lactate is present in a different compartment. These results indicate that metabolite diffusion data can be used to reveal changes in the intracellular environment depending on the pathological status.

Adult↗

PubMed2002

Clinicopathological significance of lipid peroxidation in carotid plaques.

Several reports have suggested an association between lipid peroxidation and human carotid atherosclerosis, but few reports have demonstrated a link between lipid peroxidation and carotid plaques in humans. In this study, we investigated the relationship between clinical features, histopathological characteristics and lipid peroxidation in patients undergoing carotid endarterectomy (CEA). Forty-one carotid plaques were obtained. A portion of the most severe lesions was subjected to histopathologic examination, and the remainder of the plaques examined for lipid peroxidation. Thiobarbituric acid-reactive substances (TBARS) values were determined as a marker for lipid peroxidation. The lipid-rich core (LC) and macrophage infiltration (Mphi) component as a percentage of total plaque area were measured morphometrically. Based on the results, all plaques were classified into four groups. Group I (GI): LC <10%; Group IIa (GIIa): LC 10-30%, Mphi <5%; Group IIb (GIIb): LC 10-30%, Mphi < or = 5%, and Group III (GIII): LC < or =30%. The plaque TBARS values of GIII were significantly higher than those of GI, GIIa, and GIIb. The TBARS values of GIIb were one-and-a-half times higher than those of GIIa. Our results show that lipid peroxidation in carotid plaques is significantly associated with carotid atherosclerosis, especially plaque instability. These findings provide direct evidence of an association between lipid peroxidation and human atherosclerosis.

Aged↗

PubMed2002

Can diffusion- and perfusion-weighted magnetic resonance imaging evaluate the efficacy of acute thrombolysis in patients with internal carotid artery or middle cerebral artery occlusion?

OBJECTIVE: The value of combined diffusion-weighted imaging (DWI) and perfusion-weighted imaging (PWI) for detecting ischemic lesions of patients with acute ischemic injury was analyzed. Combined pre- and posttreatment DWI and PWI studies were used to assess the efficacy of intra-arterial thrombolysis. METHODS: Intra-arterial thrombolysis was performed within 6 hours of onset in 10 patients who presented with acute middle cerebral artery or internal carotid artery occlusion. DWI and PWI obtained before and after treatment were studied. The final T2-weighted magnetic resonance scans were obtained 1 month after onset. Thrombolysis resulted in recanalization in seven patients. The mismatch ratio percentage ([initial PWI-initial DWI/initial PWI] x 100) and the rescued ratio percentage ([initial PWI-final T2/initial PWI] x 100) were calculated. The National Institutes of Health Stroke Scale (NIHSS) was used for neurological assessment of stroke severity at admission and at 1 month after onset. RESULTS: In all patients, the mismatch ratio was greater than 60% (mean +/- standard deviation, 81.7 +/- 16.7%) and was significantly correlated with initial NIHSS score (-0.74; P = 0.03), and the rescued ratio was significantly correlated with the NIHSS score 1 month after the insult (r = -0.83; P = 0.01). In patients who exhibited recanalization of the occluded artery (n = 7), the mean rescued ratio was 89.6 +/- 12.8% (range, 63-100%). In addition, the lesion volume on posttreatment DWI scans and final T2-weighted magnetic resonance images was not enlarged; on posttreatment PWI scans, it was significantly decreased. The NHISS score at 1 month after the insult (2.3 +/- 2.1) was markedly improved as compared with the initial NHISS score (10.7 +/- 3.9). CONCLUSION: In a small number of patients who presented with internal carotid artery or middle cerebral artery occlusion, the DWI/PWI mismatch ratio correlated with the initial neurological severity. The rescued ratio may be an objective indicator of the efficacy of treatment.

Aged↗