Search PubMed⌕ Search

Biomedical subjects

F Yoshii

Publications and source records attributed to F Yoshii.

At least 55 records · Page 3Linked to original sources
PubMed1989

Two behavioral states studied in a single PET/FDG procedure: error analysis.

In a previous publication the theory, procedure, and results of a method were described for making two sequential measurements of cerebral metabolic rate for glucose (CMRglc), within a 2-hr period, using [18F]fluorodeoxyglucose. The error that is specific to this technique was estimated using computer simulations. CMRglc for the second state was sensitive to errors in (a) the values of the rate constants, (b) alignment of PET slices between the two scans, and (c) subtraction of one PET image from another. The root mean square of the average error from each error source was 6.4%, which gives the theoretical reliability of this method. The measured reproducibility, taken from our previous publication, was 4.2-6.2%, which is in good agreement with the present result. This method contributes a small additional error above that expected for two independent scans. However, independent scans done on different days are likely to be subject to larger physiological variations in CMRglc than would occur using this method.

Brain↗
PubMed1988

Increases in both cerebral glucose utilization and blood flow during execution of a somatosensory task.

To investigate local metabolic and hemodynamic interrelationships during functional activation of the brain, paired studies of local cerebral glucose utilization (lCMRGlc) and blood flow (lCBF) were carried out in 10 normal subjects (9 right-handed, 1 ambidextrous) at rest and during a unilateral discriminative somatosensory/motor task--palpation and sorting of mah-jongg tiles by engraved design. The extent of activation was assessed on the basis of percentage difference images following normalization to compensate for global shifts. The somatosensory stimulus elevated lCMRGlc by 16.9 +/- 3.5% (mean +/- standard deviation) and lCBF by 26.5 +/- 5.1% in the contralateral sensorimotor cortical focus; smaller increments were noted in the homologous ipsilateral site. The increments of lCMRGlc and lCBF correlated poorly with one another in individual subjects. Stimulation of the right hand resulted in significantly higher contralateral lCMRGlc activation (19.6%) than did stimulation of the left hand (14.1%) (p less than 0.005), whereas the lCBF response was independent of the hand stimulated. Our results indicate that both glycolytic metabolism and blood flow increase locally with the execution of an active sensorimotor task and suggest that both measures may serve as reliable markers of functional activation of the normal brain.

Adult↗
PubMed1988

Sensitivity of cerebral glucose metabolism to age, gender, brain volume, brain atrophy, and cerebrovascular risk factors.

In 76 normal volunteers studied by positron emission tomography, with [18F]fluorodeoxyglucose, CMRglu was significantly lower in the elderly as compared with young subjects and significantly higher in females relative to males. However, in 58 of these subjects who also had magnetic resonance imaging scans, age and gender were found to be unrelated to CMRglu, when the effects of brain volume and brain atrophy on CMRglu were partialed out using covariate analyses. Individually, brain volume was found to have a significant effect on CMRglu, explaining approximately 17% of the variability in CMRglu measures and brain atrophy explaining approximately 8% of the variance in CMRglu. Together these two measures accounted for approximately 21% of the variance. Cerebrovascular risk factors in normal subjects were not found to affect mean CMRglu or the variability of CMRglu measures. In this study almost 80% of the variance in CMRglu could not be explained by any of the factors that had been considered. This implies a lack of sensitivity of absolute values of global CMRglu to the mild effects of brain dysfunction. Although some of the unexplained variance is probably methodological in origin, physiological factors that are difficult to quantify, such as the state of arousal, are likely to be contributory as well.

Adult↗
PubMed1988

Cerebral metabolic effects of a verbal fluency test: a PET scan study.

Sixteen normal volunteers were studied with [F-18] fluorodeoxyglucose and positron emission tomography scans during behavioral activation with a verbal fluency test, and 35 age-matched controls were studied with resting-state scans. There was an overall increase of the cerebral glucose metabolic rate of 23.3% during verbal fluency activation, compared to the resting state, with the greatest activation in bilateral temporal and frontal lobes. A negative correlation between test performance scores and indices of metabolism was found in frontal, temporal, and parietal regions. Damage to the left frontal lobe maximally affects scores on verbal fluency tests, but performing the test activates a network of regions, of which the left frontal lobe is only one. Proficient performance in verbal fluency seems to require less metabolic activation than poor performance, perhaps because of the efficiency of cognitive strategies employed.

Adult↗
PubMed1987

Computed tomographic findings in progressive supranuclear palsy.

CT findings of 6 patients with progressive supranuclear palsy (PSP) are described, with emphasis on their supratentorial changes in comparison with those of control subjects and patients with Parkinson's disease (PD). As estimated from CT films, the lateral ventricles, third ventricle and prepontine cistern were significantly enlarged in PSP patients compared with both controls and PD patients. It is suggested that the patients with PSP have not only infratentorial but also supratentorial lesions.

Aged↗
PubMed1987

Human task-specific somatosensory activation.

We used positron emission tomography to study normal patterns of local cortical metabolic activation induced by somatosensory stimuli. Palpation and sorting of mah-jongg tiles by textured design increased local glucose metabolic rate (lCMRgl), by 18% on average, in contralateral somatosensory cortex. A graphesthesia task gave a similar result. In contrast, vigorous vibrotactile stimulation of fingers, face, or knee did not produce a consistent focus of activation. Our results indicate that lCMRgl activation is best achieved by somatosensory tasks requiring an active perceptual effort.

Aged↗
PubMed1986

Two autopsy cases with ruptured dissecting aneurysm of the intracranial vertebral artery.

Two autopsy cases with ruptured dissecting aneurysm of the intracranial portion of the vertebral artery are reported. Both patients developed subarachnoid hemorrhage and died within 9 days after onset. Autopsy disclosed dissecting aneurysms symmetrically on the bilateral vertebral arteries but there was no evidence of underlying vasculopathy in either patient. The etiology of the dissecting aneurysm of the intracranial vertebral artery is obscure, but the repeated minor trauma associated with head movement is considered as an important factor.

Aortic Dissection↗
PubMed1986

Intellectual impairment in Parkinson's disease--correlation with cerebral cortical blood flow.

A contribution of cerebral cortical damage to the development of intellectual impairment in patients with Parkinson's disease (PD) has been suspected. We studied the relationship between intellectual impairment and cerebral cortical blood flow in 28 treated idiopathic parkinsonian patients. Mean IQ score as evaluated by applying the Suzuki-Binet test in patients with PD was 70.7 (+/- 12.7) and 78.6% of the patients showed abnormal score (below 80). The intellectual deficits were characterized by impairment of memory and abstract thinking, and showed a significant correlation with the severity of motor symptoms. Mean hemispheric cortical blood flow measured by using the 133xenon intravenous injection technique in patients with PD was significantly lower than that for 18 age-matched controls. Prefrontal cortical blood flow in PD was also significantly reduced compared with that in age-matched controls, showing a partial loss of hyperfrontal pattern. However, there was no significant correlation between IQ score and either mean hemispheric cortical blood flow or prefrontal cortical blood flow values. These results suggest that, although the patients with PD demonstrated a high prevalence of intellectual impairment, the impairment is not necessarily of cortical origin.

Adult↗
PubMed1985

Herpes simplex encephalitis: further evidence for persistent infection in the CNS.

Herpes simplex virus (HSV) antibody titers and IgG, IgM and IgA concentrations in the cerebrospinal fluid were serially measured in a patient with HSV encephalitis during a follow-up period of 32 months. HSV antibody titers, all classes of immunoglobulins and Ig% showed significant elevation during the course of illness, though IgM% and IgA% gradually declined after the acute phase. Autopsied brain tissue failed to yield a virus isolate, but conspicuous perivascular lymphocyte infiltrate, which is compatible with HSV encephalitis, was seen. These observations suggest the occurrence of HSV persistence and persistent antigen stimulation in the central nervous system, analogous to the well-recognized latent condition within the trigeminal ganglion.

Adult↗
PubMed1985

Neurological manifestations in chronic alcoholics.

One hundred and twenty-two chronic alcoholics were examined neurologically after more than 14 days of abstinence. A high frequency of the following was noted: abnormal smooth pursuit eye movement, hyperreflexia, snout reflex, incoordination, and signs suggesting peripheral neuropathy. Some significant mutual correlations among these neurological signs were noted, although they characteristically appeared independently and no patient showed typical clinical features of classical alcoholic neurological diseases, such as Wernicke-Korsakoff syndrome. Only abnormal smooth pursuit eye movement and incoordination showed significant correlation with nutritional status and these signs were more frequently present in the poor nutritional status group. There seemed to be a correlation between abnormal smooth pursuit eye movement and cortical atrophy on head CT scan. The possible pathogenetic mechanisms underlying these neurological abnormalities are discussed.

Adult↗
PubMed1983

Cell culture on polymers prepared by radiation-induced polymerization of various glass-forming monomers.

The growth of cells on polymers prepared by the radiation polymerization of monomethacrylate and dimethacrylate was investigated. Cell growth was affected greatly by such properties of the polymers as water content, wettability, and porosity. Growth was promoted remarkably by rinsing the polymers with warm water at 60-70 degrees C and by irradiation of polymers with an electron beam. Cell growth decreased with increasing oxyethylene length (n) in the polymerized dimethacrylate of same series, CH2C(CH3)CO(OCH2CH2)nOCOC(CH3)CH2. A decrease in the hydrophilicity of the polymer increased cell growth rate. Formation of pore structures in the polymer films also increased the cell growth.

Animals↗
PubMed1983

Cell culture on polymers prepared by radiation-induced grafting of various monomers.

The adhesion and growth of tissue cells on polymers prepared by radiation grafting was investigated. The apparent rates of initial attachment and growth of Chang liver and C6 cells were promoted on surfaces with increased wettability and with a heterogeneous structure for grafted polyvinyl fluoride film. The degree of cell attachment and growth on surfaces having a dense microblock structure, formed by grafting of methyl methacrylate in acetone solvent, was greater than that caused by other factors, such as wettability.

Animals↗
PubMed1983

Impairment of smooth pursuit eye movement in chronic alcoholics.

Smooth pursuit eye movement was quantitatively evaluated in 99 chronic alcoholics and in 100 nonalcoholic control subjects. In both groups the smooth pursuit was increasingly impaired with advancing age, but in chronic alcoholics the smooth pursuit eye movement was more frequently (42.4%) impaired than in age-matched controls (20.0%, p less than 0.005). The characteristic feature of the impairment observed in chronic alcoholics was prominent saccadic movement of the eyes; ataxic pursuit was less common. It is suggested that the impairment of smooth pursuit eye movement in alcoholics is probably attributable to 'premature aging' of the cerebral cortex caused by chronic alcohol abuse.

Adult↗