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Yuji Wada

Publications and source records attributed to Yuji Wada.

At least 19 recordsLinked to original sources
PubMed2004

[Effect of gamma-aminobutyric acid-rich germinated brown rice on indexes of life-style related diseases].

We examined the effects of gamma-aminobutyric acid-rich germinated brown rice (germinated brown rice) on principal indexes of life-style related diseases in 67 volunteers aged 71 +/- 8. They were divided into two groups; germinated brown rice group, which had an equal amount of the germinated brown rice to polished rice for 11 to 13 months, and control group, which had polished rice alone for the same period. Differences of indexes before and after the examination between the two groups were compared. Significant increases in body fat ratio, hemoglobin A1c and mean red cell volume and a significant decrease in mean red cell hemoglobin concentration were observed in the germinated brown rice group. However, there was no difference of changes in body mass index, blood pressure, serum lipid, hepatic and renal functions, bone metabolic markers, bone density, depression score, red blood cell counts, hemoglobin, hematocrit, and homeostasis model assessment of insulin resistance between the two groups. These findings suggested that germinated brown rice might not improve glucose metabolism.

Aged↗
PubMed2003

Different mechanisms of hypoxic injury on white matter and gray matter as revealed by dynamic changes in glucose metabolism in rats.

Fresh rat brain slices were incubated with [18F]2-fluoro-2-deoxy-D-glucose ([18F]FDG) in oxygenated Krebs-Ringer solution at 36 degrees C, and the fractional rate constant (=k3*) of [18F]FDG proportional to the cerebral glucose metabolic rate in white matter and gray matter was investigated with positron autoradiography. In both white matter and gray matter, the k3* value with > or = 20 min hypoxia was markedly lower than the unloaded control value, indicating irreversible hypoxic injury. Next, the neuroprotective effect against hypoxia induced by the addition of an N-methyl-D-aspartate receptor antagonist or a free radical scavenger was assessed by determining whether a decrease in the k3* value after hypoxia loading was prevented. In gray matter, both agents exhibited a neuroprotective effect against 20 min hypoxia. In white matter, however, only the free radical scavenger was effective. These results suggest a similarity in the degree of vulnerability to hypoxia between white matter and gray matter as well as a difference in the developmental mechanism of hypoxic injury, i.e. the involvement of both glutamate and free radicals in gray matter, and the more selective involvement of free radicals in white matter.

Animals↗
PubMed2003

Audio-visual integration in temporal perception.

In situations of audio-visual interaction, research has generally found that audition prevails over vision in temporal perception, while vision is dominant over audition for spatial perception. Modality appropriateness to a given task generally determines the direction of this inter-modality effect. However, we found a reverse effect in some situations where a change in the frequency of visual stimuli was associated with a perceived change in the frequency of auditory stimuli. In our experiment, 12 participants were asked to judge the change in the frequency of visual and auditory stimuli using a visual flicker and auditory flutter stimuli. In some conditions either the auditory or the visual information was ambiguous. In addition to confirming the expected finding that a change in the frequency of the auditory stimuli induced a perceived change in the frequency of the visual stimuli, we found a new phenomenon. When ambiguous auditory temporal cues were presented, the change in the frequency of the visual stimuli was associated with a perceived change in the frequency of the auditory stimuli. This suggests that cross-modal asymmetry effects are influenced by the reliability of visual and auditory information as well as modality appropriateness.

Acoustic Stimulation↗
PubMed2003

Glyceraldehyde 3-phosphate dehydrogenase and endothelin-1 immunoreactivity is associated with cerebral white matter damage in dentatorubral-pallidoluysian atrophy.

DRPLA is a rare neurodegenerative disorder caused by CAG triplet elongation on chromosome 12p. In addition to neurodegeneration of both the dentatorubral and pallidoluysian systems, there is cerebral white matter damage, especially in older cases. Intracellular accumulation of DRPLA protein is widespread in the central nervous system, and DRPLA protein has been shown to immobilize glyceraldehyde 3-phosphate dehydrogenase (GAPDH), which regulates glycolysis and controls mRNA of tissue-type plasminogen activator (tPA) in tissue restoration. However, little is known about the pathogenesis regarding the formation of cerebral white matter damage in DRPLA. Therefore, the pathology of this damage was investigated by examining markers of glycolysis and related processes. Nine clinically and pathologically confirmed DRPLA cases were used in the present study. CAG triplet elongation on chromosome 12p was confirmed in all cases where tissue was available for genotyping (seven cases). PAS and immunohistochemistry with antibodies to GFAP, GAPDH and endothelin-1 were used to demonstrate astrocytosis. The polysaccharides storage state with PAS-positive astrocytes was detected in seven cases. GAPDH- and endothelin-1-positive endothelium and astrocytes were observed in two cases with GFAP-positivity. Based on the biochemical process together with the present results, GAPDH and endothelin-1 immunoreactivity is associated with this damage and the mismetabolism of polysaccharides caused by CAG triplet elongation on chromosome 12p may contribute to the formation of the cerebral white matter damage in DRPLA.

Adolescent↗
PubMed2003

Sequential EEG analysis during intermittent photic stimulation in never-medicated patients with schizophrenia.

To investigate sequential changes in electroencephalograms (EEGs) during intermittent photic stimulation (IPS), quantitative EEG analysis for the alpha band (related to stimulus frequency) was performed in 18 drug-naïve schizophrenic patients and 18 sex- and age-matched control subjects. IPS consisted of white flickers at 10 flashes/sec, lasting 10 sec and repeated six times at 10 sec intervals. The differences between the two groups were assessed for two conditions (i.e., during photic stimulation (PS) and inter-PS). During stimulus, the absolute 9-11 Hz band power of the patient group was higher at the posterior than that at the anterior sites throughout the 10 sec periods. However, this difference between sites was not seen during the first 1 sec in the control group. During the nonstimulus period, posterior dominance of 9-11 Hz band power was prominent in the patient group throughout. In the control group, however, this difference was minor, especially during the latter half of the period. These results suggest that schizophrenic patients show fewer changes in posterior alpha activity during both stimulus and nonstimulus, and this continuity of posterior dominance may reflect hyperarousal, which counteracts any decrease in vigilance throughout the IPS.

Adolescent↗
PubMed2002

Hypoxic tolerance induction in rat brain slices following hypoxic preconditioning due to expression of neuroprotective proteins as revealed by dynamic changes in glucose metabolism.

We prepared rat brain slices following sublethal hypoxic pretreatment (preconditioning) and untreated (control) rats, and measured the cerebral glucose metabolic rate (CMRglc) by dynamic positron autoradiography with [18F]2-fluoro-2-deoxy-D-glucose before and after originally lethal 20-min hypoxic loading. In the regions of interest such as the frontal cortex, the CMRglc before hypoxic loading did not differ between the preconditioning and control groups. The CMRglc after reoxygenation was markedly lower than that before hypoxic loading in the control group but did not significantly differ from the preloading value in the preconditioning group. Thus, hypoxic tolerance induction by preconditioning was demonstrated using the maintenance of CMRglc as a neuronal viability index. In addition, profiling of gene expression using an Atlas Rat Stress Array suggested the involvement of the expression of genes such as stress protein in hypoxic tolerance induction.

Animals↗
PubMed2002

Hypoxic tolerance induction in rat brain slices following 3-nitropropionic acid pretreatment as revealed by dynamic changes in glucose metabolism.

Pretreatment with 3-nitropropionic acid (3-NPA) has been shown to induce tolerance to ischemic/hypoxic brain damage. However, regional differences in tolerance induction by 3-NPA and the degree to which impaired glucose metabolism due to 3-NPA pretreatment itself is directly involved remain unknown. To evaluate these issues using dynamic positron autoradiography with [(18)F]2-fluoro-2-deoxy-D-glucose, the cerebral glucose metabolic rate (CMRglc) was serially measured before and after hypoxia-loading in rat brain slices pretreated with 3-NPA. CMRglc before hypoxia did not significantly differ between the 3-NPA pretreatment group and control group. The 3-NPA-associated recovery of CMRglc after reoxygenation was observed in the frontal cortex, hippocampus, and cerebellum, but not in the striatum and thalamus. Thus, we demonstrated the induction of region-specific hypoxic tolerance after 3-NPA pretreatment using CMRglc maintenance as an index of neuronal viability, and it is unlikely that this induction is associated with the persistence of impaired glucose metabolism due to 3-NPA pretreatment.

Animals↗
PubMed2002

EEG harmonic responses to photic stimulation in normal aging and Alzheimer's disease: differences in interhemispheric coherence.

OBJECTIVES: The distinction between electroencephalogram (EEG) driving responses in normal aging and Alzheimer's disease (AD) is unclear. This study was conducted to explore the structure of harmonic responses of EEG coherence during photic stimulation (PS) in AD. METHODS: EEG interhemispheric coherence was analyzed for each harmonic responses during PS (white flickers at 5, 10 and 15 flashes/sec) in younger subjects (20-25 years), non-demented elderly subjects (50-67 years) and AD patients (43-66 years). RESULTS: The elderly subjects had higher interhemispheric coherence during PS than the younger subjects, with significant differences found in the 6th (30Hz) and 8th (40Hz) harmonic responses to 5Hz PS. The AD patients had significantly smaller coherence than the elderly subjects in the 2nd (10Hz) and 4th (20Hz) harmonic responses to 5Hz PS, and in the fundamental (10Hz) and 2nd (20Hz) harmonic responses to 10Hz PS. These coherence values did not correlate with duration of the disease or with cognitive functioning as evaluated by MMSE score. CONCLUSIONS: A failure of stimulation-related brain activation in AD patients was observed in alpha-related frequencies, suggesting that AD is not the end result of normal aging of the brain, at least in terms of the mechanisms which are involved in PS-related functional organization.

Aged↗
PubMed2002

A case of diffuse neurofibrillary tangles with calcification.

We report a 79-year-old female with atypical senile dementia with Fahr-type calcification. The patient started to show memory disturbance at the age of 75 years, followed by visual hallucination, stereotypy, personality changes such as irritability, aggression and disinhibition. Brain computed tomography (CT) demonstrated bilateral and symmetric calcification of the basal ganglia and thalamus. Magnetic resonance imaging (MRI) revealed diffuse cortical atrophy pronounced in the fronto-temporal areas. On MRI T1-weighted images the calcified areas showed a mixture of low- and high-intensity signals. Based on the overlapping clinical symptoms of Alzheimer's disease and Pick's disease, together with the brain CT and MRI findings, we clinically diagnosed the patient as having 'diffuse neurofibrillary tangles with calcification' (DNTC). The characteristics of psychiatric symptoms and neuroradiological findings in DNTC are discussed.

Aged↗
PubMed2002

Interhemispheric differences of the correlation dimension in a human sleep electroencephalogram.

The interhemispheric differences of the correlation dimension (D2) in the sleep electroencephalogram (EEG) of eight healthy right-handed students was investigated. During slow wave sleep (SWS) the D2 of the central EEG and the temporal left hemisphere (LH) EEG were significantly higher than those in the right hemisphere (RH) EEG; but during rapid eye movement (REM) sleep, the D2 of the central EEG and the occipital RH EEG were significantly higher. The D2 of EEG in the left temporal site during REM sleep were significantly higher than in the right during the first and third sleep cycles, but these were significantly lower during the fourth and fifth sleep cycles. During REM sleep, temporal brain activity may shift from the LH to the RH as morning approaches.

Adult↗
PubMed2002

Effect of ethanol on human sleep EEG using correlation dimension analysis.

Our study was designed to investigate the influence of alcohol on sleep using the correlation dimension (D2) analysis. Polysomnography (PSG) was performed in 10 adult human males during a baseline night (BL-N) and an ethanol (0.8 g/kg body weight) night (Et-N). The mean D2 values during the Et-N and BL-N decreased significantly from wakefulness to stages 1, 2, and 3+4 of nonrapid eye movement (non-REM) sleep, and increased during REM sleep. The mean D2 of the sleep electroencephalogram (EEG) during stage 2 during the Et-N was significantly higher than during BL-N. In addition, the mean D2 values of the sleep EEG for the second, third and fourth sleep cycles during the Et-N were significantly higher than during the BL-N. These significant differences between BL-N and Et-N were not recognized by spectral and visual analyses. Our results suggest that D2 is a potentially useful parameter for quantitative analysis of the effect of ethanol on sleep EEGs throughout the entire night.

Adult↗
PubMed2002

Differences in EEG harmonic driving responses to photic stimulation between normal aging and Alzheimer's disease.

In order to investigate whether Alzheimer's disease (AD) is the end result of aging of the brain or the result of some other mechanism, we analyzed EEGs showing the absolute power of harmonic responses to photic stimulation (PS) in younger subjects, non-demented elderly subjects and AD patients. At rest, the AD patients generally showed less absolute power than the younger and elderly subjects, with significant differences found at 10 Hz and 20 Hz. Analysis of EEGs recorded during PS indicated that the elderly subjects generally demonstrated more absolute power than the younger subjects and AD patients. These findings suggest a failure of stimulation-related brain activation in AD patients, and provide further evidence that normal aging and AD employ different mechanisms for functional organization during PS.

Adult↗
PubMed2002

Fulminant subdural empyema treated with a wide decompressive craniectomy and continuous irrigation--case report.

A 56-year-old male presented with fulminant subdural empyema manifesting as rhinorrhea, periorbital cellulitis, fever, convulsions, and consciousness disturbance. Neuroimaging showed pansinusitis with skull destruction and extensive subdural empyema. Decompressive craniectomy, irrigation of the empyema, and subdural drainage were performed. Endoscopic sinus surgery was performed to remove the source of infection at the same time. Streptococcus milleri was cultured from the pus. Continuous irrigation of the subdural space with saline containing gentamicin for 7 days resulted in prompt elimination of pus and debris. The patient was discharged with only a slight neurological deficit.

Craniotomy↗