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T Mihara

Publications and source records attributed to T Mihara.

At least 19 recordsLinked to original sources
PubMed2006

Detection of new anti-neutral glycosphingolipids antibodies and their effects on Trk neurotrophin receptors.

We screened sera from patients with various neurological disorders for the presence of anti-neutral glycosphingolipids antibodies and only found them in sera from relapsing polychondritis with limbic encephalitis patients. Neutral glycosphingolipids are resident in membrane lipid rafts where high affinity nerve growth factor (NGF) receptor, Trk is co-localized. Therefore, we examined whether these antibodies influence the action of NGF in NGF-responsive cells. The results strongly suggest that these antibodies enhance NGF-induced Trk autophosphorylation and neurite outgrowth as well as neurofilament M expression. These data strongly indicate that these anti-neutral glycosphingolipids antibodies have a functional impact on NGF-Trk-mediated intracellular signal transduction pathway.

Animals↗
PubMed2006

Photoemission from buried interfaces in SrTiO3/LaTiO3 superlattices.

We have measured photoemission spectra of SrTiO3/LaTiO3 superlattices with a topmost SrTiO3 layer of variable thickness. A finite coherent spectral weight with a clear Fermi cutoff was observed at chemically abrupt SrTiO3/LaTiO3 interfaces, indicating that an "electronic reconstruction" occurs at the interface between the Mott insulator LaTiO3 and the band insulator SrTiO3. For SrTiO3/LaTiO3 interfaces annealed at high temperatures (approximately 1000 degrees C), which leads to Sr/La atomic interdiffusion and hence to the formation of La(1-x)Sr(x)TiO3-like material, the intensity of the incoherent part was found to be dramatically reduced whereas the coherent part with a sharp Fermi cutoff was enhanced due to the spread of charge. These important experimental features are well reproduced by layer dynamical-mean-field-theory calculation.

Journal Article↗
PubMed2005

Helicobacter pylori infection influences symptomatic response to anti-secretory therapy in patients with GORD--crossover comparative study with famotidine and low-dose lansoprazole.

BACKGROUND AND AIM: Helicobacter pylori infection was reported to affect gastric acid secretion. We investigated the heartburn symptoms of patients with gastro-oesophageal reflux disease during sequential treatment with 40 mg of famotidine or 15 mg of lansoprazole to clarify whether H. pylori infection influences symptomatic response to anti-secretory therapy. SUBJECTS AND METHODS: The subjects were 33 gastro-oesophageal reflux disease patients, who had already been treated with a full dose of H2 receptor antagonist. First, famotidine at 20 mg b.i.d. was administered to the patients for 8 weeks. Second, famotidine was replaced with 15 mg of lansoprazole once in the morning for 8 weeks. Finally, 20 mg of famotidine was administered b.i.d. for 8 weeks instead of lansoprazole. Gastro-oesophageal reflux disease symptoms were assessed using an original visual analogue scale. RESULTS: The sequential symptomatic responses to famotidine and lansoprazole administration indicated that gastro-oesophageal reflux disease symptoms of patients during low-dose lansoprazole treatment were significantly less than those during famotidine treatment. Remission of symptoms was obtained significantly more often by famotidine therapy in patients with H. pylori infection than in patients without H. pylori infection. CONCLUSION: Low-dose lansoprazole is more effective than full-dose famotidine for the control of symptoms in patients with gastro-oesophageal reflux disease, and H. pylori infection influences the symptomatic response to H2 receptor antagonists.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed2004

Helicobacter pylori infection prevents the occurrence of the tolerance phenomenon of histamine H2 receptor antagonists.

BACKGROUND: The attenuated anti-secretory activity of H2 receptor antagonists (H2RA) during continuous administration is referred to as the tolerance phenomenon. However, it is not clarified whether Helicobacter pylori infection affects the occurrence of tolerance to H2RA. It is also not clarified whether the tolerance phenomenon occurs to a new H2RA, lafutidine. AIM: To investigate the occurrence of the tolerance phenomenon in subjects with and without H. pylori infection during the continuous administration of lafutidine and famotidine. SUBJECTS AND METHODS: Subjects were 20 healthy male volunteers (seven H. pylori positive and 13 H. pylori negative cases). All subjects were examined by ambulatory intragastric pH monitoring five times without medication, on the first and 15th day of the administration of 20 mg b.d. famotidine and 10 mg b.d. lafutidine in a cross-over fashion. RESULTS: The tolerance phenomenon was not observed in H. pylori-positive subjects during the 15-day-long administration of both H2RAs. In contrast, the tolerance phenomenon was observed in H. pylori negative subjects, which has been previously reported. CONCLUSIONS: This study demonstrated that H. pylori infection affects the tolerance phenomenon during continuous administration of H2RAs.

Acetamides↗
PubMed2003

Energetic protons from a few-micron metallic foil evaporated by an intense laser pulse.

With detailed experimental studies and hydrodynamics and particle-in-cell simulations we investigate the role of the prepulse in laser proton acceleration. The prepulse or pedestal (amplified spontaneous emission) can completely evaporate the irradiated region of a sufficiently thin foil; therefore, the main part of the laser pulse interacts with an underdense plasma. The multiparametric particle-in-cell simulations demonstrate that the main pulse generates the quasistatic magnetic field, which in its turn produces the long-lived charge separation electrostatic field, accelerating the ions.

Journal Article↗
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

MRI of cortical dysplasia--correlation with pathological findings.

Cortical dysplasia (CD) is the most epileptogenic structural lesion associated with epilepsy and patients with intractable seizures caused by this condition are good surgical candidates. MRI plays an important role in detecting the abnormalities of CD. We clarified the MRI characteristics of CD by comparing imaging and histological findings in 20 patients with intractable seizures who underwent surgical resection. There were 12 males and eight females, mean age at operation was 15 years. MRI was performed at 1.5 tesla; T1-weighted, T2- and proton density-weighted spin-echo and fluid-attenuated inversion-recovery (FLAIR) images were obtained. The lesions were in the frontal lobe in nine cases, temporal in two, occipital in another two, insular in one and multilobar in six. Blurring of the grey/white matter junction was seen in all patients, and T2 prolongation in white matter and/or at the grey/white matter junction in 19. Abnormal signal intensity was more frequent in the white matter or at the grey/white matter junction than in the grey matter. FLAIR images made this abnormal high signal easier to appreciate, and we thought them very useful in this context. In areas of T2 prolongation, we saw dysplastic neurones and/or balloon cells, dysmyelination, and ectopic neuronal clustering histologically; glial proliferation played an important role in prolonging T2.

Adolescent↗
PubMed2001

Acute psychosis during intracranial EEG monitoring: close relationship between psychotic symptoms and discharges in amygdala.

PURPOSE: This report examined the underlying mechanism of psychosis associated with epilepsy. METHODS: An adult patient with epilepsy manifesting acute psychosis during long-term EEG monitoring is presented, together with a literature review on this subject. RESULTS: A 25-year-old woman with intractable temporal lobe epilepsy developed acute psychosis while she underwent long-term intracranial EEG monitoring. After a clustering of seizures, she manifested psychotic symptoms including hallucination, stupor, and repeated fear. The transition of psychotic symptoms corresponded to the changes in frequency and morphology of seizure discharges restricted to the left amygdala. Improvement of psychosis coincided with disappearance of seizure discharges. CONCLUSIONS: This case confirmed a close relationship between psychotic symptoms and seizure discharges in the left amygdala. It is suggested that paroxysmal bombardment of the medial temporal lobe structure may be a pathogenetic factor of acute psychosis associated with epilepsy.

Acute Disease↗
PubMed2001

[Neuroimaging and electrophysiological study in epilepsy].

There exist various morphological and biochemical changes closely associated with electrophysiological phenomena which cause epileptic seizures in the brains of epilepsy patients. Recent developments in investigation methods, not only electrophysiological(EEG and MEG), but also neuroimaging involving morphological imaging(CT and conventional MRI) and functional imaging(SPECT, PET, functional MRI and MRS) is able to demonstrate these changes. SPECT and PET can particularly clarify the changes of cerebral blood flow and glucose metabolism between interictal and ictal periods. In our experience of 423 patients who underwent epilepsy surgery for intractable seizures, these interventions provide important information to identify the epileptogenic foci. However, in practice, discordance in the results of these presurgical evaluations is recognized, and invasive intracranial recordings are needed in such cases. These problems in diagnosis were shown especially in patients with mesial temporal sclerosis and focal cortical dysplasia. To detect an epileptogenic focus more clearly, a combination of morphological and functional findings, new functional imaging such as neurotransmitter receptor imaging, EEG-triggered or neuropharmacological functional MRI, as well as, statistical parametric analysis may be needed.

Electroencephalography↗
PubMed2001

Psychiatric disorders before and after surgery for epilepsy.

PURPOSE: To examine the frequency of psychiatric disorders before and after surgery for epilepsy and the postoperative changes. METHODS: We examined the psychiatric status of 226 patients aged 18 years or older and with IQ >50 who underwent focal resection surgery after age 15 years at our center and were followed up for >2 years after surgery. RESULTS: Seventy-eight (34.5%) patients had psychiatric disorders before and/or after surgery, comprising 36 patients with psychosis, 15 with affective disorders, and 27 with neurotic/behavioral disorders. All but four of these patients had temporal lobe epilepsy. Of the 61 patients who had psychiatric disorders before surgery, 22 patients were free of psychiatric symptoms after surgery (eight with psychosis, 13 with neurotic/behavior disorders, one with affective disorders), and 39 patients continued having psychiatric symptoms after surgery (22 with psychosis, 12 with neurotic/behavior disorders, five with affective disorders). Nine patients had a transient affective disorder that appeared 1-2 months after surgery and disappeared within 1-2 months. In eight patients, chronic psychiatric symptoms manifested after surgery (psychosis in six cases, neurotic/behavior disorders in two), one of whom exhibited postictal psychosis after drug noncompliance. Psychosis that disappeared after surgery was often seizure related. The patients with aggravated psychiatric conditions after surgery had a lower age at epilepsy onset and at surgery, and exhibited deviated personality traits even before surgery. CONCLUSIONS: One third of the surgical patients had psychiatric disorders before and/or after surgery. Preexisting psychiatric problems disappeared after surgery in one third of the patients, but persisted after surgery in the remaining patients, with aggravation in a few. Transient affective disorders appeared in some patients immediately after surgery, and chronic psychiatric disorders appeared after surgery in a minority of patients. The patients having aggravated psychiatric conditions after surgery tended to be young and to have deviated personality traits. The social situation of the patients having psychiatric disorders after surgery was not good.

Adolescent↗
PubMed2001

Neuroradiologic findings in focal cortical dysplasia: histologic correlation with surgically resected specimens.

PURPOSE: We investigated the neuroradiologic characteristics of focal findings of surgically resected specimens obtained from 47 patients with focal cortical dysplasia (FCD). METHODS: Forty cases were detected by magnetic resonance imaging (MRI), and two cases were detected only by single-photon emission computed tomography (SPECT), but five cases could not be detected before operation. RESULTS: MRI revealed abnormal gyri and sulci in 34 patients (pachygyric in 18, polymicrogyric in 10, both in six), and blurring of the gray matter-white matter junction in 29 (72%) patients. Signal abnormalities were found in 36 (90%) patients, in the gray matter in 32, with white matter in 30, and at the gray matter-white matter junction in 13. Moreover, peculiar patterns of abnormal signals in the white matter were recognized, including remarkably abnormal subcortical signals of T2 hyperintensity and T1 hypointensity adjacent to the dysplastic cortex in 15 cases, high radiated T2 signals extending from the ependymal surface of the lateral ventricle to the overlying cortex in 11 cases, and widespread abnormal signals in the white matter with gray matter involvement in four cases. Histologically, these abnormal signals corresponded to various degrees of dyslamination and morphologic abnormalities of neurons and glial cells in the gray matter, and to dysmyelination, ectopic clustering of dysplastic neurons, glial proliferation, and necrotic change in the white matter. Regional cerebral blood flow SPECT showed interictal hypoperfusion in 29 (62%) of the 47 patients, interictal hyperperfusion in two, and ictal hyperperfusion in 28 of the 34 patients associated with FCD. [123I]iomazenil SPECT demonstrating the distribution of central benzodiazepine receptors showed low accumulations localized spatially corresponding to the epileptogenic foci associated with FCD in seven of eight patients. CONCLUSIONS: These results demonstrate that neuroimaging reflects various structural and functional changes closely related to epileptogenesis in FCD.

Adolescent↗
PubMed2000

Absence of simple partial seizure in temporal lobe epilepsy: its diagnostic and prognostic significance.

The diagnostic and prognostic significance of the absence of simple partial seizures (SPS) immediately preceding complex partial seizures (CPS) was examined in patients with temporal lobe epilepsy. The status of self-reported SPS in 193 patients with temporal lobe epilepsy who had surgical therapy more than 2 years ago was reviewed. Before surgery, 37 patients never experienced SPS before CPS (Group A), 156 patients either always or occasionally had SPS before CPS (Group B). The frequency of mesial temporal sclerosis (MTS) was lower and the age at onset of epilepsy was higher in Group A. The seizure focus was in the language-dominant temporal lobe in 73% of the cases in Group A, compared with 40% in Group B. The surgical outcome did not differ between the two groups. The findings suggest that temporal lobe seizures without preceding SPS tend to originate in the language-dominant temporal lobe that contains a pathologic etiology other than MTS, especially in the lateral temporal lobe. The surgical outcome in patients without SPS is similar to that in patients with SPS.

Adolescent↗
PubMed2000

Electrocorticogram-electromyogram coherence during isometric contraction of hand muscle in human.

OBJECTIVE: To clarify how the primary sensorimotor and supplementary motor areas are involved in the generation of the rhythmicity of electromyogram (EMG) activity during continuous muscle contraction. METHOD: We analyzed the coherence between subdurally recorded cortical electroencephalograms (EEG) and EMGs of the contralateral wrist extensor muscle during continuous isometric contraction in 8 patients with medically intractable epilepsy. RESULTS: In all subjects, a significant coherence between the primary motor area (M1) and EMG was observed at the peak frequency of 15+/-3 Hz (means+/-SD). In the primary somatosensory area (S1) of 7 subjects and the supplementary motor area proper (SMA proper) of 4 subjects, significant coherence with EMG was observed at 12+/-5 and 15+/-4 Hz, respectively. The time lags revealed by cross-correlogram were 10+/-3, 7+/-1 and 22+/-8 ms in the M1, S1 and SMA proper, respectively, with the EMG lagging in all areas. CONCLUSION: These findings suggest that the rhythmic activity in the SMA proper, as well as in the S1 and M1, is related to the generation of the rhythmicity of EMG activity.

Electromyography↗
PubMed2000

Movement-related change of electrocorticographic activity in human supplementary motor area proper.

We investigated movement-related change in the cortical EEG signal by simultaneous recording from the primary sensorimotor area (S1-M1) and the supplementary motor area proper (SMA proper) in four patients with intractable partial epilepsy. By the use of temporal spectral evolution (TSE) analysis, the change in background cortical activity in relation to self-paced finger/wrist extension was compared among the SMA proper, S1 and M1. All three areas showed a decrease in the amount of activity for the frequency range between 10 and 40 Hz before the onset of movement [event-related desynchronization (ERD)]. The SMA proper showed earlier onset of ERD for 18-22 Hz activity (-3.4 +/- 0.5 s, mean +/- standard deviation) than M1 (-1.7 +/- 0.7 s) and S1 (-1.4 +/- 0.5 s). The degree of ERD in S1 was greatest for 10-14 Hz and that in M1 for 18-22 Hz, whereas in the SMA proper ERD was observed throughout the frequency bands from 10 to 40 Hz. Neither the degree nor the onset time of ERD in the SMA proper was lateralized to either the ipsilateral or the contralateral side with respect to the movement. A transient increase in activity after movement [event-related synchronization (ERS)] was observed in all three areas. In the SMA proper, two out of four subjects showed ERS for frequency bands below 40 Hz with both ipsilateral and contralateral movements. By contrast, in S1 and M1, ERS was recorded for frequency bands between 20 and 90 Hz, and was predominantly associated with the contralateral movement. The present study suggests that the background cortical activity in the SMA proper has a specific temporal pattern with respect to self-paced movement, and that the SMA proper is involved in motor preparation earlier than S1-M1 in a bilaterally organized manner.

Adult↗
PubMed2000

[Outcomes of home anti-cancer chemotherapy--estimation of hepatic arterial infusion chemotherapy for patients with multiple liver metastases].

A total of 18 patients (13: colon cancer, 5: gastric cancer) with multiple liver metastases (H3) underwent hepatic arterial infusion chemotherapy (HAI) using an implanted arterial port with portable syringe pumps in our outpatient clinic. Clinical perspective: overall response rate was 22.2% (CR: 1 case, PR: 3 cases (1 case: hepatectomy after HAI), NC: 12 cases, PD: 2 cases), however, 7 of 12 cases of NC were long NC (more than 6 months). No major complications with HAI were experienced. Patient Perspective: After HAI in our outpatient clinic, the 50% survival was 341 days, 50% hospital free days were 319 days and home stay rate was 92.9%. Societal Perspective: cost and hospital stay days were significantly reduced. Home anti-cancer chemotherapy using HAI for gastrointestinal cancer patients with multiple liver metastases was safe and efficient from the viewpoint of medical outcomes.

Aged↗
PubMed1999

Peptidic immunosuppressants from the fungus Trichoderma polysporum.

Three new 10-residue lipopeptaibols, trichopolyns III-V have been isolated from the fungus Trichoderma polysporum together with the known trichopolyns I and II. Structure determination has been achieved on the basis of spectroscopic and chemical evidence. These peptides have been shown to suppress the proliferation of lymphocytes in mouse allogeneic mixed lymphocyte reaction.

Animals↗
PubMed1999

[Arg8]-vasopressin-induced increase in intracellular Ca2+ concentration in cultured rat hippocampal neurons.

Changes in intracellular Ca2+ concentration ([Ca2+]i) induced by [Arg8]-vasopressin (AVP) were studied in cultured rat hippocampal neurons by fura-2 fluorometry. AVP (10-1,000 nM) caused a dose-dependent increase in [Ca2+]i. The selective V1 vasopressin receptor agonist [Phe2, Ile3, Orn8]-vasopressin also induced a significant increase in [Ca2+]i, whereas the selective V2 vasopressin receptor agonist [deamino Cys1, D-Arg8]-vasopressin showed no effect. The AVP-induced increase in [Ca2+]i was inhibited by the selective V1 vasopressin receptor antagonist d(CH2)5[Tyr2(Me), Arg8]-vasopressin and nonpeptide V1 antagonist OPC-21268. On the other hand, no antagonistic effects were observed with the V2 vasopressin antagonist desglycinamide-[d(CH2)5, D-Ile2, Ile4, Arg8]-vasopressin and nonpeptide V2 antagonist OPC-31260. The increase in [Ca2+]i induced by AVP was abolished after removal of extracellular Ca2+. In addition, AVP-induced [Ca2+]i elevation was not affected by treatment with verapamil, which blocked the [Ca2+]i increase induced by an isotonic high K(+)-medium (50 mM). However, omega-conotoxin GVIA completely inhibited the effect of AVP. These results suggested that the AVP-induced [Ca2+]i increase in cultured rat hippocampal neurons is due to influx of Ca2+ through V1 VP receptors coupled with N-type calcium channels.

Animals↗