PubMed Health⌕ Search

Biomedical subjects

Toshiki Yoshimine

Publications and source records attributed to Toshiki Yoshimine.

At least 19 recordsLinked to original sources
PubMed2006

Effects of the emotional connotations in words on the frontal areas--a spatially filtered MEG study.

The objective of this study was to elucidate how and where emotional connotations in words influenced linguistic processing in the language-related areas. We recorded neuromagnetic signals in nine right-handed and one left-handed healthy volunteers while they silently read emotional and emotionless words written in Japanese kanji characters, and investigated the distribution of the cerebral oscillatory changes using synthetic aperture magnetometry. Event-related desynchronizations (ERDs) in the beta-low gamma bands were observed in the anterior cingulate cortex (ACC) that were specific to the reading of emotional words in seven of nine right-handers. Beta-low gamma band ERDs were also detected in the left inferior or middle frontal gyrus (IFG or MFG) in nine right-handers regardless of the tasks. The magnitude of the ERDs in the IFG or MFG was significantly greater during emotional-word reading than during emotionless-word reading in nine right-handers. Left-dominant ERDs in the beta and gamma bands were observed in the prefrontal cortex (PFC) when negative emotional words were read (i.e. sadness), while right-dominant ERDs were observed for positive emotional words (i.e. happiness) in seven of nine right-handers (p=0.012, corrected). In one left-hander, the ERD in the ACC and the greater ERD that occurred in the IFG that was specific to emotional-word reading were also observed, but their lateralities in the IFG and PFC were reversed. These results suggest that emotional connotations in words facilitated the ERDs in the frontal language-related areas, and that these facilitations might be modulated by emotional processing in the ACC. Furthermore, negative and positive emotional words may be processed by different mechanisms.

Adult↗
PubMed2006

Magnetoencephalographic analysis of cortical oscillatory activity in patients with brain tumors: Synthetic aperture magnetometry (SAM) functional imaging of delta band activity.

Abnormal focal slow wave activity on electroencephalography and magnetoencephalography (MEG) is often seen in patients with various brain pathologies and MEG is capable of localizing cortical oscillatory activity with enhanced accuracy. In addition, MEG with synthetic aperture magnetometry (SAM) can depict changes in cortical oscillatory activity tomographically. Using SAM, we recorded cortical rhythms in patients with a brain tumor and evaluated the tomographic appearance of focal slow wave activity in relation to clinical signs and symptoms. Spontaneous MEG recordings were obtained in 15 patients with brain tumors. Statistically-determined power distributions in the delta-, theta-, and alpha-frequency bands were displayed tomographically and overlaid on individual magnetic resonance images. The location, strength and volume of enhanced activity were analyzed. Delta and theta band activities were significantly more intense in the cortex adjacent to tumors and in the surrounding edematous cortical areas than in other portions of the cortex. In 13 of the 15 patients, spatial distribution of enhanced focal delta activity coincided with the area responsible for the presenting signs and symptoms. Volumetric analysis revealed that emergence of tumor-related focal delta band activity in the cortex adjacent to a tumor, or with peritumoral edema, was greater for intra-axial tumors involving subcortical fibers than for extra-axial tumors. Patients with an increased volume of enhanced delta activity exhibited poor recovery of function in the early postoperative period. It is concluded that SAM imaging of focal delta activity can reveal functional alterations in cortical activity in patients with brain tumors and is useful for assessing cortical states associated with the existing pathology.

Adult↗
PubMed2006

Spatially filtered magnetoencephalographic analysis of cortical oscillatory changes in basic brain rhythms during the Japanese 'Shiritori' Word Generation Task.

BACKGROUND: 'Shiritori' (capping verses) is a traditional Japanese word generation game, and is very familiar to native Japanese speakers. The shiritori task is expected to more strongly activate temporal language-related regions than conventional word generation to letters because of its characteristic way to make cue letters. OBJECTIVES: The aim of this study was to examine the cortical oscillatory changes in basic brain rhythms during silently performing a shiritori task. METHODS: Using synthetic aperture magnetometry (SAM) analysis of magnetoencephalography, we estimated the tomographic distributions of the statistically significant differences of the power in the alpha and beta frequency bands between the resting and the task periods. RESULTS: Significant event-related desynchronization (ERD) in the 8- to 25-Hz band, thought to reflect neural activation, was localized within task-related cortical regions with left-side dominance. The significant ERDs were estimated in both the frontal and temporal language-related regions encompassing Broca's and Wernicke's areas, although previous neuroimaging studies using word generation to letters showed neural activation predominantly in frontal regions. CONCLUSIONS: Our results show the potential of SAM analysis for reliable brain mapping of language processing, and suggest that the shiritori task might be more suitable for examining the language-related network in the brain than conventional word generation to letters.

Adult↗
PubMed2006

A phase I/II trial of a WT1 (Wilms' tumor gene) peptide vaccine in patients with solid malignancy: safety assessment based on the phase I data.

OBJECTIVE: We conducted a phase I study to investigate the safety of a weekly WT1 tumor vaccine therapy in patients with solid tumors that had been refractory to all other anti-cancer therapies. METHODS: Skin-test-negative patients were intradermally injected weekly for 12 weeks with 3.0 mg of an HLA-A*2402-restricted modified 9-mer WT1 peptide emulsified in Montanide ISA51 adjuvant. We estimated the Bayesian posterior probability of the occurrence of grade 3 or 4 toxicity when receiving the weekly WT1 vaccination. This analysis provided the basis for making a decision to terminate the phase I study and switch to phase II. Moreover, we performed an exploratory assessment of the anti-tumor effects of WT1 treatment. RESULTS: Ten patients received 114 vaccinations with WT1 on a weekly schedule. No grade 3 or 4 toxicities were observed. Based on the Bayesian approach, it was highly likely that the probability of grade 3 or 4 toxicity was below 20% (the posterior probability = 0.914). Fifteen grade 2 and two grade 1 toxicities were observed; all of these incidents, however, were determined by the Independent Data and Safety Monitoring Committee to be unrelated to the WT1 treatment. One patient exhibited a partial response; five additional patients had stable disease while receiving weekly WT1 treatment. CONCLUSION: This paper confirms that the potential toxicities of the treatment schedule of weekly WT1 vaccination are acceptable and suggested a potential anti-tumor effect. Consequently, we validated the decision to continue to the phase II trial.

Adolescent↗
PubMed2006

Neuromagnetic changes of brain rhythm evoked by intravenous olfactory stimulation in humans.

To identify the changes in the respective frequency band and brain areas related to olfactory perception, we measured magnetoencephalographic (MEG) signals before and after instilling intravenously thiamine propyl disulfide (TPD) and thiamine tetrahydrofurfuryl disulfide monohydrochloride (TTFD), which evoked a strong and weak sensation of odor, respectively. For the frequency analysis of MEG, a beamformer program, synthetic aperture magnetometry (SAM), was employed and event-related desynchronization (ERD) or synchronization (ERS) was statistically determined. Both strong and weak odors induced ERD in (1) beta band (13-30 Hz) in the right precentral gyrus, and the superior and middle frontal gyri in both hemispheres, (2) low gamma band (30-60 Hz) in the left superior frontal gyrus and superior parietal lobule, and the middle frontal gyrus in both hemispheres, and (3) high gamma band 2 (100-200 Hz) in the right inferior frontal gyrus. TPD induced ERD in the left temporal, parietal and occipital lobes, while TTFD induced ERD in the right temporal, parietal and occipital lobes. The results indicate that physiological functions in several regions in the frontal lobe may change and the strength of the odor may play a different role in each hemisphere during olfactory perception in humans.

Adult↗
PubMed2006

Reduction of intractable deafferentation pain by navigation-guided repetitive transcranial magnetic stimulation of the primary motor cortex.

The precentral gyrus (M1) is a representative target for electrical stimulation therapy of pain. To date, few researchers have investigated whether pain relief is possible by stimulation of cortical areas other than M1. According to recent reports, repetitive transcranial magnetic stimulation (rTMS) can provide an effect similar to that of electrical stimulation. With this in mind, we therefore examined several cortical areas as stimulation targets using a navigation-guided rTMS and compared the effects of the different targets on pain. Twenty patients with intractable deafferentation pain received rTMS of M1, the postcentral gyrus (S1), premotor area (preM), and supplementary motor area (SMA). Each target was stimulated with ten trains of 10-s 5-Hz TMS pulses, with 50-s intervals in between trains. Intensities were adjusted to 90% of resting motor thresholds. Thus, a total of 500 stimuli were applied. Sham stimulations were undertaken at random. The effect of rTMS on pain was rated by patients using a visual analogue scale (VAS) and the short form of the McGill Pain Questionnaire (SF-MPQ). Ten of the 20 patients (50%) indicated that stimulation of M1, but not other areas, provided significant and beneficial pain relief (p<0.01). Results indicated a statistically significant effect lasting for 3 hours after the stimulation of M1 (p<0.05). Stimulation of other targets was not effective. The M1 was the sole target for treating intractable pain with rTMS, in spite of the fact that M1, S1, preM, and SMA are located adjacently.

Adult↗
PubMed2006

The loss of local HGF, an endogenous gastrotrophic factor, leads to mucosal injuries in the stomach of mice.

The stomach is constantly exposed to mechanical and chemical stresses. Under persistent damages, epithelial cell proliferation is required to maintain mucosal integrity. Nevertheless, which ligand system(s) is physiologically involved in gastric defense remains unclear. Herein, we provide evidence that HGF is a key "natural ligand" to reverse gastric injury. The injection of cisplatin in mice led to the loss of HGF in the gastric interstitium, associated with the decrease in proliferating epithelium and the progression of mucotitis. When c-Met tyrosine phosphorylation was abolished by anti-HGF IgG, mucosal cell proliferation became faint, leading to delayed recovery from mucotitis, and vice versa in cases of HGF supplementation. Our findings indicate that: (1) HGF/c-Met signal on mucosa is needed to restore gastric injuries; and (2) the loss of local HGF leads to manifestation of gastric lesions. This study provides a rationale that explains why HGF supplement is useful for reversing gastric diseases.

Animals↗
PubMed2006

Fixative method of carotid shunt using a Sugita's fenestrated aneurysm clip as a device in carotid endarterectomy technical note.

BACKGROUND: Difficulty for distal exposure of the ICA is sometimes encountered during CEA. A carotid shunt is used to maintain sufficient cerebral blood flow during CEA but requires fixative materials, such as a string or a metallic ring, which often restrict the operative field, especially that of the distal ICA. METHODS: Here, we describe a novel technique for carotid shunt fixation using a unique fixative device in CEA. In the method presented here, the carotid shunt is fixed with an inflated balloon and a conventional vascular tourniquet proximally, but distal fixation is achieved using a Sugita's fenestrated clip that catches the mid portion of the carotid shunt and surrounding tissue. RESULTS AND CONCLUSION: The device prevents the distal carotid shunt slipping out of the distal ICA. The present method allows mobilization of the shunt position during CEA and facilitates far-distal exposure of the ICA.

Brain Infarction↗
PubMed2006

Short-term preoperative octreotide treatment of GH-secreting pituitary adenoma: predictors of tumor shrinkage.

We reviewed the cases of 32 patients with growth hormone (GH)-secreting macroadenoma who underwent short-term octreotide treatment before transsphenoidal surgery to determine which types of adenoma the preoperative treatment were sensitive and whether predictors of tumor shrinkage could be identified. The effects of preoperative octreotide treatment, endocrinologic effect and effect on tumor volume in 32 patients were evaluated retrospectively in relation to tumor features on magnetic resonance images and responses to endocrinologic challenge tests. At a daily dose of 300 microg for 2-3 weeks, octreotide reduced serum GH and insulin-like growth factor-1 (IGF-1) levels to 31.9 % and 51.6% of pretreatment values, respectively, and led to a mean tumor volume of 68% of pretreatment volume in 52% of the patients. The endocrinologic effect and the effect on tumor volume were larger in Knosp grades 0-2 than in Knosp grades 3-4. Tumor shrinkage occurred significantly more often among patients that had a good response to both octreotide and bromocriptine challenge tests. For surgical removal of the tumor, the effect of reducing tumor to 68% of pretreatment volume will be beneficial for the macroadenomas of Knosp grades 1-2. Preoperative short-term octreotide treatment is effective for GH-secreting macroadeomas of Knosp grades 1-2 and a good response to both octreotide and bromocriptine challenge tests is a predictor of subsequent tumor shrinkage. These results will lead to more effective selection of patients for preoperative octreotide treatment.

Acromegaly↗
PubMed2006

Reduction of a pancreatic tumor after total removal of an ACTH secreting pituitary tumor: differential diagnosis of Cushing's syndrome.

Endocrinologic tests sometimes fail to distinguish adrenocorticotropic hormone (ACTH)-secreting pituitary adenoma from ectopic ACTH-secreting tumor. The authors experienced a case of Cushing's disease associated with a pancreatic tumor. Venous sampling contributed to the final diagnosis of Cushing's disease in this complex case, while endocrinologic tests showed paradoxical results. A 54-year-old woman presented with Cushing's syndrome and pancreatic tumor. Magnetic resonance imaging (MRI) failed to reveal a pituitary tumor, but a gadolinium-enhanced tumor with cystic components was seen in the pancreatic tail. Results of conventional endocrinologic tests suggested ectopic ACTH syndrome, but venous sampling including cavernous sinus sampling indicated an ACTH-secreting pituitary adenoma. Transsphenoidal surgery revealed a pituitary microadenoma, and total removal of the tumor was achieved. Postoperative abdominal MRI revealed that the pancreatic tumor diminished gradually without treatment. Selective cavernous sinus sampling was useful for distinguishing ACTH-secreting pituitary adenoma from ectopic ACTH syndrome in this complex case. This was a rare case in which the pancreatic tumor diminished after total removal of the ACTH-secreting pituitary adenoma.

ACTH Syndrome, Ectopic↗
PubMed2006

Skull metastases from atypical pulmonary carcinoid tumor in a 19-year-old man.

A 19-year-old man presented with a rare skull metastasis from atypical pulmonary carcinoid tumor (APCT) manifesting as headache, diplopia, and cough. Head magnetic resonance imaging showed a skull base tumor extending from the posterior clinoid process to the clivus, and calvarial tumors in the right temporal and occipital bones. Chest and abdominal computed tomography showed a round tumor, 4 cm in diameter, in the lower lobe of the right lung and multiple small tumors in the liver. Surgery for the calvarial tumor in the right temporal bone was performed on June 27, 2003. The histological diagnosis was skull metastasis of neuroendocrine tumor. Gamma knife radiosurgery was performed for the residual skull metastases. Partial resection of the right lower lobe was performed for the lung tumor on August 22, 2003. The histological diagnosis was atypical carcinoid tumor. Subsequent adjuvant systematic chemotherapy was performed. The patient died of progression of the tumors in the lung and liver on April 19, 2004. We must consider APCT in the differential diagnosis of pulmonary tumors in adolescents, and perform follow-up observation or treatment, including surgery, if APCT is suspected.

Adult↗
PubMed2006

Medical application of an infrared free-electron laser: selective removal of cholesterol ester in carotid artery atheromatous plaques.

OBJECT: . The purpose of this study was to determine the effectiveness of infrared free-electron laser (FEL) irradiation of cholesterol esters in human carotid artery (CA) atheromas. METHODS: The degradation of cholesterol ester was estimated from changes in the infrared absorption spectra acquired using microscopic transmission Fourier transform infrared spectroscopy. An FEL emitting radiation at 5.75-microm wavelengths and a power density of 15.9 W/cm2 was used to treat intimal slices of extirpated human arterial atherosclerotic plaques. Peak signals derived from an ester bond of cholesterol ester decreased in height as irradiation time increased and disappeared completely after 180 seconds. No other change was observed in the infrared absorption spectrum after 180 seconds of irradiation, and no histological damage was noted. CONCLUSIONS: The authors concluded that FEL irradiation can remove cholesterol ester selectively from human atheromatous CA plaques. This novel technique differs from previous approaches involving conventional lasers.

Atherosclerosis↗
PubMed2006

Microscopic bilateral decompression through unilateral laminotomy for lumbar canal stenosis in patients undergoing hemodialysis.

OBJECT: Microscopic bilateral decompression through a unilateral laminotomy (MBDUL) is a minimally invasive technique used to treat lumbar canal stenosis (LCS). In the present study, MBDUL was performed to treat LCS in eight patients undergoing hemodialysis. METHODS: Surgical outcomes were evaluated using the Japanese Orthopaedic Association (JOA) scale (highest possible score 29). The JOA scale was administered preoperatively, at 1 month and 3 months postoperatively, and at the final follow-up examination. One patient refused to undergo the postoperative assessment after the 1-month examination; the mean follow-up duration of the remaining seven patients was 24 months (range 18-31 months). The mean age at the time of surgery was 62 years (range 48-76 years), and the mean duration of hemodialysis therapy was 21.4 years (range 3-28 years). All patients could walk within 2 days of surgery. The mean angle of the straight leg-raising (SLR) test was 53.8 degrees preoperatively, and this increased to 69.4 degrees postoperatively. Six patients felt enhancement of sciatica or leg pain when performing the SLR test preoperatively, a finding that was absent postoperatively at least until the final follow-up examination. The mean preoperative JOA score was 11.6 (range 4-22), and the score markedly improved to 19.8 (range 15-23) at 1 month and 20.6 (range 16-25) at 3 months. The mean JOA score decreased to 17.1 (range 12-25) at the final follow-up examination, but this decrease was attributed to other physical disorders. CONCLUSIONS: The authors conclude that MBDUL is a safe and effective surgical treatment for patients undergoing hemodialysis who are suffering from LCS.

Aged↗
PubMed2006

[Endonasal endoscopic chiasmapexy for secondary empty sella syndrome following fenestration of a Rathke's cleft cyst].

Drainage by fenestration of the cyst wall via the transsphenoidal apporach is the most commonly used treatment for symptomatic Rathke's cleft cyst (RCC). The same procedure is usually adopted for recurrence of RCC. We have encountered a case of secondary empty sella syndrome presented with visual field defects after repeated surgery for RCC. Secondary empty sella syndrome following the surgery of RCC is rare. The condition was explained by the mechanism that the optic nerve adhered to the cyst wall and it was tethered downward as the cyst shrank after the surgery. We treated the patient via the endonasal endoscopic transsphenoidal approach by placing holed silicone plates under the sellar floor to elevate the sellar contents and the optic nerve. Silicone plate is hard enough to support the sella and the small holes on it would facilitate drainage of the cyst contents. This method has proved useful as chiasmapexy for secondary empty sella syndrome after the surgery of RCC.

Adult↗
PubMed2005

Information processing flow and neural activations in the dorsolateral prefrontal cortex in the Stroop task in schizophrenic patients. A spatially filtered MEG analysis with high temporal and spatial resolution.

Using a spatially filtered magnetoencephalography analysis (synthetic aperture magnetometry), we estimated neural activations in the Stroop task in nearly real time for schizophrenic patients with/without auditory hallucinations and for normal control subjects. In addition, auditory hallucinations were examined through the information processing flow of the brain neural network, including the frontal regions. One hundred unaveraged magnetoencephalography signals during the incongruent stimulus responses were analyzed with a time window of 200 ms in steps of 50 ms. In the 25-60-Hz band, cortical regions that showed significant current source density changes were examined for each time window. The three groups showed significantly decreased current source density, corresponding to neural activation, with temporal overlap along the fundamental cognitive information processing flow: sensory input system, executive control system, motor output system. Transient neural activations in the dorsolateral prefrontal cortex were bilateral with left-side dominancy for normal controls, left-lateralized for nonhallucinators and right-lateralized for hallucinators. Our results suggest that the dysfunction in the left dorsolateral prefrontal cortex was related to auditory hallucinations, while the information processing flow was unaffected in the schizophrenic subjects in the Stroop task.

Adolescent↗
PubMed2005

Fiber-tracking does not accurately estimate size of fiber bundle in pathological condition: initial neurosurgical experience using neuronavigation and subcortical white matter stimulation.

The fiber-tracking method enables in vivo visualization of the white matter tracts of the brain using a diffusion tensor MR imaging technique. While this method represents a promising tool in the field of neurosurgery, especially when confronted with brain tumors in eloquent areas, its reliability remains unknown. We present here our preliminary validation of tractography in human subjects harboring brain tumors by comparing the results produced by neuronavigation and electrical white matter stimulation in two patients with gliomas in the eloquent area. Although we were able to visualize the pyramidal tract with the fiber-tracking technique, the images failed to present the actual size of the fiber bundles. Here we discuss the advantages and limitations of fiber-tracking in the field of neurosurgery.

Aged↗
PubMed2005

Peri-infarct depolarizations reveal penumbra-like conditions in striatum.

Spreading depression-like peri-infarct depolarizations not only characterize but also worsen penumbra conditions in cortical border zones of experimental focal ischemia. We intended to investigate the relevance of ischemic depolarization in subcortical regions of ischemic territories. Calomel electrodes measured DC potentials simultaneously in the lateral and medial portions of the caudate nucleus (CN) of 11 anesthetized cats after permanent occlusion of the middle cerebral artery. Additionally, platinum electrodes measured cerebral blood flow (CBF) in the CN, and laser Doppler probes CBF in the cortex. Depolarizations (negative DC shifts >10 mV) were obtained in 10 of 11 cats. Further differentiation revealed that short-lasting spreading depression-like depolarizations (SDs; 5 of 10 cats: 5.24 +/- 1.22 min total duration; 23.3 +/- 4.2 mV amplitude) were predominantly found in medial and longer depolarizations (LDs; 4 of 10 cats: 64.7 +/- 47.5 min; 25.0 +/- 11.3 mV) in the lateral CN. Terminal depolarizations (TDs; 6 of 10 cats; without repolarization) occurred immediately after occlusion or at later stages, being then accompanied by elevations of intracranial pressure presumably inducing secondary CBF reduction. CBF tended to be lower in regions with TDs (33.3 +/- 29.9% of control) and LDs (37.3 +/- 22.8%) than in regions with SDs (51.5 +/- 48.0%). We conclude that in focal ischemia, transient peri-infarct depolarizations emerge not only in cortical but also in striatal gray matter, thereby demonstrating the existence of subcortical zones of ischemic penumbra. The generation of these ischemic depolarizations is a multifocal process possibly linked to brain swelling and intracranial pressure rise in the later course of focal ischemia, and therefore a relevant correlate of progressively worsening conditions.

Animals↗