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Biomedical subjects

A Ikeda

Publications and source records attributed to A Ikeda.

At least 37 records · Page 2Linked to original sources
PubMed2004

Search for electron neutrino appearance in a 250 km long-baseline experiment.

We present a search for electron neutrino appearance from accelerator-produced muon neutrinos in the K2K long-baseline neutrino experiment. One candidate event is found in the data corresponding to an exposure of 4.8 x 10(19) protons on target. The expected background in the absence of neutrino oscillations is estimated to be 2.4+/-0.6 events and is dominated by misidentification of events from neutral current pi(0) production. We exclude the nu(micro) to nu(e) oscillations at 90% C.L. for the effective mixing angle in the 2-flavor approximation of sin((2)2theta(microe)( approximately 1/2sin((2)2theta(13))>0.15 at Deltam(2)(microe)=2.8 x 10(-3) eV(2), the best-fit value of the nu(micro) disappearance analysis in K2K. The most stringent limit of sin((2)2theta(microe)<0.09 is obtained at Deltam(2)(microe)=6 x 10(-3) eV(2).

Journal Article↗
PubMed2004

Surgical treatment of seizures from the peri-Sylvian area by perinatal insult: a case report of ictal hypersalivation.

UNLABELLED: OBJECTIVES AND IMPORTANCE: It is important to evaluate the seizure manifestation of epilepsy before surgical planning. A patient with partial epilepsy manifesting hypersalivation who underwent resection of the epileptogenic foci with satisfactory postoperative seizure control is reported. CLINICAL PRESENTATION AND INTERVENTION: A 26-year-old man, with a history of perinatal asphyxia, started having medically intractable partial epilepsy at the age of 10 years. His seizure was characterized by throat discomfort followed by hypersalivation. Brain MRI showed an atrophic lesion around the peri-Sylvian area. Scalp recorded EEG did not demonstrate robust epileptiform activity localized enough to define the epileptogenic zone. The patient underwent invasive recording by multiple subdural electrode grids, which showed that the seizure arose from the left anterior frontal operculum. After resection of epileptogenic opercular cortex, the seizures disappeared with no additional neurological deficits. CONCLUSION: Although the responsible sites for ictal drooling are distributed in multiple areas including insula, medial temporal area and operculum, the seizure can be successfully controlled by focus resection of the frontal opercular area in a selected patient with careful presurgical evaluation.

Adult↗
PubMed2004

Subregions of human MT complex revealed by comparative MEG and direct electrocorticographic recordings.

OBJECTIVE: To locate the visual motion complex (MT+) and study its response properties in an epilepsy surgery patient. METHODS: A 17-year-old epilepsy patient underwent invasive monitoring with subdural electrodes in the right temporo-parieto-occipital area. MT+ was investigated by cortical electric stimulation and by epicortical visual evoked potentials time-locked to motion onset of sinusoidal gratings (motion VEP). Motion-related visual evoked magnetic field (motion VEF) was also recorded before the electrode implantation to complement the invasive recording. RESULTS: Motion VEPs revealed two subregions within MT+, generating early and late potentials respectively. The early activity with a peak around 130 ms was localized at a single electrode situated immediately caudal to the initial portion of the ascending limb of the superior temporal sulcus (AL-STS). The late activity, peaking at 242-274 ms, was located ventro-rostrally over three electrodes. Among the four electrodes with motion VEPs, cortical stimulation at the most caudal pair elicited motion-in-depth perception involving the whole visual field. In addition to two subregions revealed on the gyral crown, magnetoencephalography (MEG) demonstrated another subregion with a late motion VEF in AL-STS immediately rostral to the electrode with the early motion VEP. CONCLUSIONS: In combination with MEG recording, the present invasive exploration demonstrated human MT+ in a focal area of the temporo-parieto-occipital junction and delineated possible three subregions as indicated by the different latencies and distributions of the motion VEP/VEFs. SIGNIFICANCE: Comparative MEG and direct electrocorticographic recordings delineated possible subregions within the human MT complex.

Adolescent↗
PubMed2004

Longitudinal changes in health status using the chronic respiratory disease questionnaire and pulmonary function in patients with stable chronic obstructive pulmonary disease.

Long-term changes in health status have been less evaluated in patients with chronic obstructive pulmonary disease (COPD), in comparison to the changes in forced expiratory volume in 1 s (FEV1). Accordingly, we examined the clinical course of health status as well as pulmonary function in COPD patients, and investigated the relationship between the change in health status and the change in pulmonary function in a 3-year longitudinal study involving 224 patients with COPD. Health status using the Chronic Respiratory Disease Questionnaire (CRQ) and pulmonary function were measured at baseline and every six months over three years. We used the random effects model for the slopes to estimate the longitudinal changes. A total of 147 patients completed the 3-year study. The dyspnoea, fatigue, and emotional function domains of the CRQ declined slowly but significantly over 3 years (p = 0.001, 0.003, and 0.004, respectively) with a mean decline rate of 0.08/year. This means that it would take about 6 years to reach the minimal important change of 0.5 on the CRQ. The mean decline in post-bronchodilator FEV1 was 60 ml/year. None of the changes in any of the domains of the CRQ were significantly correlated with the changes in pulmonary function. We have found that, in comparison to the decline in pulmonary function, health status evaluated by the CRQ declined significantly but very slowly in three of four domains over three years in patients with COPD. Furthermore, we have demonstrated that there was no significant relationship between the change in health status and the change in pulmonary function.

Aged↗
PubMed2003

Indications of neutrino oscillation in a 250 km long-baseline experiment.

The K2K experiment observes indications of neutrino oscillation: a reduction of nu(mu) flux together with a distortion of the energy spectrum. Fifty-six beam neutrino events are observed in Super-Kamiokande (SK), 250 km from the neutrino production point, with an expectation of 80.1(+6.2)(-5.4). Twenty-nine one ring mu-like events are used to reconstruct the neutrino energy spectrum, which is better matched to the expected spectrum with neutrino oscillation than without. The probability that the observed flux at SK is explained by statistical fluctuation without neutrino oscillation is less than 1%.

Journal Article↗
PubMed2003

Seizures arising from the inferior parietal lobule can show ictal semiology of the second sensory seizure (SII seizure).

A 52-year-old right handed man presented with medically intractable partial seizures consisting of numbness on the left upper back spreading to the left upper as well as lower limbs. Head computed tomography and magnetic resonance imaging showed a round calcified lesion in the depth of the superior ramus of the right sylvian fissure. Ictal electrocorticographic recording with chronically implanted subdural electrodes showed low voltage fast activities starting exclusively from an electrode located on the right inferior parietal lobule. No apparent ictal activities were observed from the depth electrodes inserted in the parietal operculum. Somatosensory evoked potentials of 75 ms to 145 ms latency were recorded from the ictal onset zone, which was 2 cm caudal to the perisylvian area corresponding to the second somatosensory area. Seizures arising from the inferior parietal lobule including the angular and supuramarginal gyri can produce partial seizures whose ictal semiology and scalp electroencephalography are indistinguishable from the ones originating from the second somatosensory area.

Evoked Potentials, Somatosensory↗
PubMed2003

Improvement of central motor conduction after bone marrow transplantation in adrenoleukodystrophy.

The case is described of a 20-year-old man with adrenoleukodystrophy who showed right spastic hemiparesis and gait disturbance. Brain magnetic resonance imaging disclosed predominant involvement of the left corticospinal pathway. The clinical symptoms improved after bone marrow transplantation. Transcranial magnetic stimulation disclosed significant improvement in various parameters of central motor conduction.

Adrenoleukodystrophy↗
PubMed2003

Inverse correlation between serum leptin concentration and vertebral bone density in postmenopausal women.

Although the protective effect of obesity on bone mass has been ascribed to high body fat content, this is still controversial. The present study of 215 postmenopausal Japanese women investigated whether circulating leptin concentration was correlated with per cent fat mass or age-adjusted bone mineral density (Z-score). In this study population, the mean circulating leptin concentration was 10.15 +/- 5.42 (range 1.7-29.6) ng/ml. Significant correlations were found between circulating leptin concentrations and per cent fat mass (r = 0.514, p < 0.0001) and Z-score (r = -0.516, p < 0.0001), confirming the existence of an inverse relationship between leptin concentration and postmenopausal bone density. By contrast, no significant correlation was found between per cent abdominal fat mass and vertebral bone mineral density (r = -0.071). Serum leptin concentration reflects fat mass and postmenopausal bone mass in human subjects. Increased serum leptin levels might cause bone loss in postmenopausal Japanese women, and our results do not support the hypothesis that leptin induces or mediates the bone-protective effects of obesity.

Abdomen↗
PubMed2002

Neuroleptic malignant syndrome with prolonged catatonia in a dopa-responsive dystonia patient.

The authors describe a patient with dopa-responsive dystonia who developed neuroleptic malignant syndrome with prolonged catatonia following treatment with neuroleptic agents. Use of these agents probably expanded the patient's neuronal dysfunction beyond the nigrostriatal system to involve multiple dopaminergic systems. Electroconvulsive treatment alleviated the prolonged catatonia.

Adult↗
PubMed2002

Health status measured with the CRQ does not predict mortality in COPD.

One purpose of measuring health status is to predict future outcomes. The aim of this study was to investigate the ability of health status derived from the Chronic Respiratory Disease Questionnaire (CRQ) to predict mortality in chronic obstructive pulmonary disease (COPD). One-hundred and forty-three patients with COPD were recruited. Health status, using the CRQ, and pulmonary function were measured at entry. Mortality after 7 yrs was then assessed. Univariate and multivariate Cox proportional hazards analyses were performed to predict those factors related to mortality. Of all the patients, 13 could not be followed up and 40 had died. The survival rate was 69% at 7 yrs. Univariate regression analyses revealed that the dyspnoea and emotional function domains and the total score of the CRQ were weakly but significantly correlated with mortality from all causes. However, multivariate regression analyses revealed that age and forced expiratory volume in one second were the strongest predictors of mortality, and health status was not a significant factor. Although there was a weak but significant relationship between health status and subsequent mortality in chronic obstructive pulmonary disease, it was not significant after an adjustment for age and pulmonary function. Mortality cannot be predicted from Chronic Respiratory Disease Questionnaire scores.

Age Factors↗
PubMed2001

Effects of the combined use of calcitonin and 1 alpha-hydroxycholecalciferol on vertebral bone loss and bone turnover in women with postmenopausal osteopenia and osteoporosis: a prospective study of long-term and continuous administration with low dose calcitonin.

OBJECTIVES: The present study investigates the effect of long-term and continuous treatment with low dose calcitonin in combination with 1 alpha-hydroxycholecalciferol on vertebral bone mass in early postmenopausal women. METHODS: A total of 202 postmenopausal women between 53 and 58 years of age were recruited individually and randomly assigned to one of four groups. Comparisons were made among groups of women receiving calcitonin alone (10 IU i.m. twice a month), 1 alpha-hydroxycholecalciferol alone (0.5 microg orally twice daily), a combination of the above two agents, or no treatment. Bone mineral density (BMD) of lumber spine (L2-4) was determined using Dual Energy X-ray Absorptiometry. The study was carried out prospectively over a 2-year period. RESULTS: We observed a significant increase in vertebral bone mass in the combined treatment regimen of calcitonin and 1 alpha-hydroxycholecalciferol (3.44% at 12 months in the combination group vs 1.40,0.92, and -0.70% in the calcitonin alone, 1 alpha-hydroxycholecalciferol alone, and control groups, respectively; 4.51% at 24 months in the combination group vs 2.21,1.04, and -3.61% in the calcitonin alone, 1 alpha-hydroxycholecalciferol alone, and control groups, respectively). Serum PTH, osteocalcin levels and alkaline phosphatase activity decreased significantly within 12 months whereas urinary pyridinoline/creatinine ratio decreased at 24 months in the combination group. We observed mild adverse effects in 25.0% (7/28) and 30.0% (6/20) of combination regimen and calcitonin treatment cases, respectively. CONCLUSIONS: The results of the study suggest that the combination treatment regimen increased vertebral bone loss in early postmenopausal women to a greater extent than did calcitonin alone or 1 alpha-hydroxycholecalciferol alone.

Administration, Oral↗
PubMed2001

Increased synchronization of cortical oscillatory activities between human supplementary motor and primary sensorimotor areas during voluntary movements.

In human, both primary and nonprimary motor areas are involved in the control of voluntary movements. However, the dynamics of functional coupling among different motor areas has not been fully clarified yet. Because it has been proposed that the functional coupling among cortical areas might be achieved by the synchronization of oscillatory activity, we investigated the electrocorticographic coherence between the supplementary motor and primary sensorimotor areas (SMA and S1-M1) by means of event-related partial coherence analysis in 11 intractable epilepsy patients. We found premovement increase of coherence between the SMA proper and S1-M1 at the frequency of 0-33 Hz and between the pre-SMA and S1-M1 at 0-18 Hz. Coherence between the SMA proper and M1 started to increase 0.9 sec before the movement onset and peaked 0.3 sec after the movement. There was no systematic difference within the SMA (SMA proper vs pre-SMA) or within the S1-M1, in terms of the time course as well as the peak value of coherence. The phase spectra revealed near-zero phase difference in 57% (20 of 35) of region pairs analyzed, and the remaining pairs showed inconsistent results. This increase of synchronization between multiple motor areas in the preparation and execution of voluntary movements may reflect the multiregional functional interactions in human motor behavior.

Adolescent↗
PubMed2001

Neural tube defects and neuroepithelial cell death in Tulp3 knockout mice.

The tubby-like protein 3 (Tulp3) gene has been identified as a member of a small novel gene family which is primarily neuronally expressed. Mutations in two of the family members, tub and tulp1, have been shown to cause neurosensory disorders. To determine the in vivo function of Tulp3, we have generated a germline mutation in the mouse Tulp3 gene by homologous recombination. Embryos homozygous for the Tulp3 mutant allele exhibit failure of neural tube closure, and die by embryonic day 14.5. Failure of cranial neural tube closure coincided with increased neuroepithelial apoptosis specifically in the hindbrain and the caudal neural tube. In addition, the number of betaIII-tubulin positive cells is significantly decreased in the hindbrain of Tulp3(-/-) embryos. These results suggest that disruption of the Tulp3 gene affects the development of a neuronal cell population. Interestingly, some Tulp3 heterozygotes also manifest embryonic lethality with neuroepithelial cell death. Our results demonstrate that the Tulp3 gene is essential for embryonic development in mice.

Animals↗