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T Yoshimine

Publications and source records attributed to T Yoshimine.

At least 19 recordsLinked to original sources
PubMed2000

Induction of aquaporin-4 water channel mRNA after focal cerebral ischemia in rat.

Aquaporin-4 (AQP4) is a member of a water-selective channel aquaporin-family and mainly expressed in the several structures of the brain and in the collecting duct of the kidney. Here we show its functional involvement in the water homeostasis of the ischemic brain. The expression of AQP4-mRNA is increased in the peri-infarcted cortex during the observation period ( approximately 7 days) after MCA-occlusion, maximally on day 3. The change corresponds to the generation and resolution of brain edema monitored by MRI. The signals for the mRNA are predominantly observed in glial cells in the molecular and outer granular layer of the peri-infarcted cortex. These results indicate that AQP4 plays a role in post-ischemic edema formation.

Animals↗
PubMed2000

Quantitative analysis of glioma cell invasion by confocal laser scanning microscopy in a novel brain slice model.

To quantitatively analyze the spatial extent of glioma cell migration in an organotypic brain slice culture, we developed a new invasion model with the aid of confocal laser scanning microscopy (CLSM). CLSM allowed not only for three-dimensional visualization of the invasive pattern of human T98G glioma cells in the living brain slice but also for serial analysis of the invasive process over several weeks. Twenty-four hours after the T98G glioma spheroid was initiated to coculture with a brain slice, the glioma cells detached themselves from the spheroid and spontaneously continued to migrate on the surface of the brain slice, while they diffusely invaded into the slice by migrating to a deeper site. Immunohistochemical analysis revealed that these migrating glioma cells much more strongly immunostained for matrix metalloproteinase (MMP)-2 and -9 than the tumor spheroid which remained at the implanted site. Treatment of the T98G glioma spheroid with 1,10-phenanthroline, a specific inhibitor of MMPs, significantly inhibited not only the cell migration on the surface of the brain slice but also the invasion of the glioma cells into the slice. The present version of the glioma invasion model using CLSM makes it possible to spatially and serially analyze the extent of glioma cell invasion in the living brain slice for several weeks, making it a very useful tool for investigating the cellular and molecular mechanisms of glioma invasion under conditions most analogous to those of normal brains in vivo.

Animals↗
PubMed2000

Movement-related desynchronization of the cerebral cortex studied with spatially filtered magnetoencephalography.

Event-related desynchronization (ERD) within the alpha and beta bands on unilateral index finger extension and hand grasping was investigated on six normal volunteers with magnetoencephalography (MEG). A novel spatial filtering technique for imaging cortical source power, synthetic aperture magnetometry (SAM), was employed for the tomographic demonstration of ERD. SAM source image results were transformed into statistical parametric images. On the same hand grasping task, a functional MRI (fMRI) study was conducted on two subjects and compared with the ERD result. When the MEG data were analyzed with the fast Fourier transformation, power attenuation within the alpha and beta bands was evident on the contralateral sensorimotor area just prior to movement onset. The tomographic distribution of ERD was clearly obtained with SAM statistical imaging analysis. The equivalent current dipole (ECD) for the signal-averaged motor field was localized to the hemisphere contralateral to the hand movement, roughly at the center of the region displaying beta-band ERD. The signal increase on fMRI roughly colocalized with the ERD on the contralateral sensorimotor area. In conclusion, with the novel spatial filtering technique for the brain magnetic field, SAM, cortical regions contributing to ERD on finger movement were successfully demonstrated in a tomographic manner. The relative colocalization of the contralateral SAM ERD with ECD as well as the fMRI activation suggests that SAM is a practically useful technique to extract event-related signals from brain noise.

Adult↗
PubMed2000

Ultrastructural changes of the vascular endothelium after intra-arterial administration of tumor necrosis factor-alpha (TNFalpha) in rat gliomas.

The ensuing ultrastructural changes in tumor vascular endothelial cells following intra-arterial administration of tumor necrosis factor-alpha (TNFalpha) were studied in an experimental rat glioma model. C6 glioma cells were implanted in Wistar rats and then after 14 days, 5 x 10(3) U of human natural-type TNFalpha (1.7 x 10(5) U/m2) was administered through the carotid artery. The animals were sacrificed at 3 or 24 h after TNFalpha treatment. A detailed examination with transmission electron microscope revealed swelling of the tumor vascular endothelial cell nuclei and mitochondria with matrix densities at 3 h. At 24 h, these cells demonstrated the presence of high amplitude mitochondrial swelling or the violent blebbing characteristic of damaged mitochondria; the cytoplasm was swollen enormously and there were dissolution of cytoplasmic organelles and rupture of the plasma membrane. The observed findings were typical of cell necrosis and confirms yet another mechanism by which TNFalpha exerts its anti-tumor effects, that is, necrotizing effects on tumor vascular endothelium. The information appears to be important in the context of clinical application of intra-arterial TNFalpha in the treatment of malignant gliomas.

Animals↗
PubMed2000

Widespread gene transfection into the central nervous system of primates.

We attempted in vivo gene transfection into the central nervous system (CNS) of non-human primates using the hemagglutinating virus of Japan (HVJ)-AVE liposome, a newly constructed anionic type liposome with a lipid composition similar to that of HIV envelopes and coated by the fusogenic envelope proteins of inactivated HVJ. HVJ-AVE liposomes containing the lacZ gene were applied intrathecally through the cisterna magna of Japanese macaques. Widespread transgene expression was observed mainly in the neurons. The lacZ gene was highly expressed in the medial temporal lobe, brainstem, Purkinje cells of cerebellar vermis and upper cervical cord (29.0 to 59.4% of neurons). Intrastriatal injection of an HVJ-AVE liposome-lacZ complex made a focal transfection around the injection sites up to 15 mm. We conclude that the infusion of HVJ-AVE liposomes into the cerebrospinal fluid (CSF) space is applicable for widespread gene delivery into the CNS of large animals. Gene Therapy (2000) 7, 759-763.

Animals↗
PubMed2000

Elastase expression by infiltrating neutrophils in gliomas.

Polymorphonuclear neutrophil elastase is a neutral protease released by activated polymorphonuclear neutrophils and plays a crucial role in maintaining host defense. However, under certain conditions, this enzyme damages normal tissue and facilitates infiltration of tumor cells. In this study, surgical specimens were obtained from the tumor core and infiltrating margin of the glioma of 12 patients with astrocytoma of varying degrees of malignancy, and the specimens were tested for the presence of elastase by immunohistochemical analysis. Polymorphonuclear neutrophil elastase was not present in the tumor core of any of the 12 cases. Elastase was expressed in areas of tumor infiltration of the brain in all four glioblastoma cases, three of the four anaplastic astrocytoma cases, and none of the four low-grade astrocytoma cases. There was a higher percentage of elastase-positive polymorphonuclear neutrophils in the infiltrating margin of tumors with greater degree of malignancy. Polymorphonuclear neutrophils are recruited to malignant gliomas, and the elastase released by these cells aids in the infiltration of gliomas.

Aged↗
PubMed2000

Effectiveness of spray application of ACNU in the local control of malignant gliomas: report of two cases.

Malignant gliomas encompassing the eloquent areas cannot be removed totally and their surgical extirpation is followed by adjuvant therapy for the residual tumor. Recently, we have employed fibrin glue as a vehicle for the sustained release of ACNU (nimustine hydrochloride) by spray application following subtotal tumor removal in two patients with recurrent malignant gliomas. Follow-up MRI at six months demonstrated no neuroradiological evidence of tumor recurrence in the site of operation. We conclude, this novel mode of intra-operative local chemotherapy by spray application of fibrin glue containing antineoplastic agent is effective in the control of residual tumor progression and may also prevent local recurrence and hence suggests its possible role as an adjuvant therapy in the management of malignant gliomas.

Aerosols↗
PubMed2000

Scalp marking for a craniotomy using a laser pointer during preoperative computed tomographic imaging: technical note.

OBJECTIVE: The preoperative localization of superficial intracranial lesions is often necessary for accurate burr hole placement or craniotomy siting. It is not always easy, however, to localize the lesions over the scalp working only from computed tomographic images. We developed a simple method for such localization using a laser pointer during the preoperative computed tomographic examination. METHODS: The angle of incidence, extending from a point on the scalp to the center of the computed tomographic image, is measured by the software included with the scanner. In the gantry, at the same angle as on the image, a laser is beamed from a handmade projector onto the patient's scalp toward the center of the gantry. The point illuminated on the patient's head corresponds to that on the image. The device and the method are described in detail herein. RESULTS: We applied this technique to mark the area for the craniotomy before surgery in five patients with superficial brain tumors. At the time of surgery, it was confirmed that the tumors were circumscribed precisely. CONCLUSION: The technique is easy to perform and useful in the preoperative planning for a craniotomy. In addition, the device is easily constructed and inexpensive.

Brain Neoplasms↗
PubMed2000

Motor cortex stimulation for central and peripheral deafferentation pain. Report of eight cases.

The authors tested a modified motor cortex stimulation protocol for treatment of central and peripheral types of deafferentation pain. Four patients with thalamic pain and four with peripheral deafferentation pain were studied. Preoperative pharmacological tests of pain relief were performed using phentolamine, lidocaine, ketamine, thiopental, and placebo. In five patients we placed a 20- or 40-electrode grid in the subdural space to determine the best stimulation point for pain relief for a few weeks before definitive placement of a four-electrode array. In three patients, the four-electrode array was implanted in the interhemispheric fissure as a one-stage procedure to treat lower-extremity pain. In two patients with pain extending from the extremity to the trunk or hip, dual devices were implanted to drive two electrodes. Six of eight patients experienced pain reduction (two each with excellent, good, and fair relief) from motor cortex stimulation. No correlation was apparent between pharmacological test results and the effectiveness of motor cortex stimulation. Patients with peripheral deafferentation pain, including two with phantom-limb pain and two with brachial plexus injury, attained pain relief from motor cortex stimulation, with excellent results in two cases. Testing performed with a subdural multiple-electrode grid was helpful in locating the best stimulation point for pain relief. Motor cortex stimulation may be effective for treating peripheral as well as central deafferentation pain.

Aged↗
PubMed2000

A giant intracranial mucocele associated with an orbitoethmoidal osteoma. Case report.

The authors present a rare case of a giant intracranial mucocele associated with an orbitoethmoidal osteoma in a patient suffering from a generalized convulsive disorder. The broad pedicle of the osteoma had penetrated the cribriform plate and extended intracranially to form a nodular mass in the olfactory groove. The intracranial portion of the osteoma was surrounded by a mucocele. Both the cyst wall and multilayered intracystic septations of the mucocele were indented by layers of the osteoma. Although the extracranial portion adhered to the mucosa of the ethmoidal sinus, there were no signs of sinus obstruction. No direct communication other than the osteoma was identified between the mucocele and the ethmoidal mucosa. The large cerebral defect, which the mucocele occupied, communicated directly with the lateral ventricle without any intervening membranous structures. A frontal craniotomy is recommended for exposure of the lesion and plastic repair of the dural defect.

Brain Diseases↗
PubMed1999

BDNF atelocollagen mini-pellet accelerates facial nerve regeneration.

We investigated the effect of BDNF mini-pellet on the GAP-43 mRNA expression and functional status of facial nerve in a rat model of facial nerve transection and immediate repair. The facial function started to recover at 17 days in the placebo group and 14 days in the BDNF group. BDNF group had shorter period of increased GAP-43 mRNA expression than the placebo group. Topically applied BDNF may accelerate the facial nerve regeneration.

Animals↗
PubMed1999

Kainic acid-induced seizure upregulates Na(+)/myo-inositol cotransporter mRNA in rat brain.

A major organic osmolyte, myo-inositol protects cells from perturbing effects of high intracellular concentrations of electrolytes. Myo-inositol is accumulated into cells through Na(+)/myo-inositol cotransporter (SMIT). In order to investigate the regulation of SMIT in generalized seizure, we employed Northern blot analysis and in situ hybridization to study the changes in SMIT mRNA expression in kainic acid-injected rats. Northern blot analysis demonstrated that SMIT mRNA began to increase in the brain 2 h after onset of seizure, and peaked at 12 h. In situ hybridization revealed rapid increase of SMIT mRNA (2 h of seizure) in the CA3 hippocampal pyramidal cells and in the dentate granular cells. Then, at 4-6 h SMIT mRNA expression was observed in the other limbic structure such as amygdala and piriform cortex. Finally, in neocortex and in CA1 pyramidal cells, SMIT mRNA was slowly increased and peaked at 12 h. Microautoradiogram demonstrated that cells expressed SMIT mRNA were mainly neurons. These results suggest that SMIT mRNA is upregulated by kainic acid-induced seizure primarily in structures involved in seizure activity.

Animals↗
PubMed1999

Medial prefrontal cortex generates frontal midline theta rhythm.

Frontal midline theta rhythm (Fm theta) is a distinct theta activity of EEG in the frontal midline area that appears during concentrated performance of mental tasks in normal subjects and reflects focused attentional processing. To tomographically visualize the source current density distributions of Fm theta, we recorded Fm theta by using a 64-channel whole-head MEG system from four healthy subjects, and applied a new analysis method, synthetic aperture magnetometry (SAM), an adaptive beam forming method. Fm theta was observed in the MEG signals over the bilateral frontal regions. SAM analysis showed bilateral medial prefrontal cortices, including anterior cingulate cortex, as the source of Fm theta. This result suggests that focused attention is mainly related to medial prefrontal cortex.

Adult↗
PubMed1999

Isolation and expression analysis of a novel human homologue of the Drosophila glial cells missing (gcm) gene.

A novel human homologue (GCMB) of the Drosophila glial cells missing gene (dGCM) was isolated using RACE. GCMB contained a gcm motif sequence and a nuclear targeting sequence similar to that of dGCM and mouse GCMb. Homology searches indicated that GCMB was located within chromosome 6p24.2. Transcripts of GCMB were detected by means of RT-PCR in fetal brain, normal adult kidney, 3/3 medulloblastomas, 1/3 gliomas and 4/8 non-neuroepithelial tumor cell lines. Our data suggest that humans have two homologues of gcm like mice and that human gcm genes form a novel family which may function not only during fetal development but also in the postnatal or pathological stage.

Amino Acid Sequence↗
PubMed1999

Chromosomal aberrations detected by comparative genomic hybridization (CGH) in human astrocytic tumors.

We investigated chromosomal aberrations in 16 patients with astrocytic tumors of various histologic malignancies by comparative genomic hybridization (CGH). The degree of chromosomal loss was shown to be negatively correlated with histologic malignancy. Losses of portions of chromosomes 1p, 19q and 22q were the three chromosomal aberrations observed most frequently. Alterations in multiple chromosomes were observed more frequently in glioblastomas than in astrocytomas or anaplastic astrocytomas (P < 0.001). Primary glioblastomas showed a high frequency of genomic DNA gains (5/7), whereas recurrent glioblastomas from anaplastic astrocytomas did not (0/3). We found CGH to be a powerful tool for surveying DNA alterations in tumors and characterizing the biology of tumors of astrocytic lineage.

Adult↗
PubMed1999

Hemangioblastoma of the third ventricle.

A third ventricle tumor, in addition to a recurrent cerebellar hemangioblastoma, was found in a 47-year-old woman on follow-up magnetic resonance imaging (MRI) 5 years after operation of the cerebellar tumor. On MRI, the tumor was hypo- to isointense on T1-weighted images and hyperintense on T2-weighted images compared with the normal gray matter, and was strongly enhanced with gadolinium. The tumor was first treated with fractionated conventional external-beam radiation (5120 cGy in 16 fractions over a 4-week period), resulting in a slight decrease in size of the tumor. For a definite diagnosis and mass reduction, surgery was performed using an interhemispheric translamina terminalis approach, resulting in a partial removal of the tumor due to profuse bleeding. Histological diagnosis was hemangioblastoma. Hemangioblastomas of the third ventricle are extremely rare and have not been specifically discussed. We describe the detailed clinicopathological features of the present case together with the possible explanation for the development of this tumor in this rare location.

Cerebellar Neoplasms↗