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T Yoshimoto

Publications and source records attributed to T Yoshimoto.

At least 523 records · Page 29Linked to original sources
PubMed1994

A novel aspect of thrombin in the tissue reaction following central nervous system injury.

Thrombin and two different types of control solutions (buffer and albumin) were continuously infused into the rat caudoputamen by an osmotic minipump. Routine histological studies with immunohistochemistry using antibodies for BrdU, GFAP, vimentin and laminin were carried out to assess infiltration of inflammatory cells, formation of edema, cell proliferation, and reactivity of astrocytes and mesenchymal cells. The number of inflammatory cells, number of BrdU positive cells, area and number of vimentin positive astrocytes, and the area of GFAP-positive reactive astrocytes were quantitatively analyzed. In the thrombin group, pale tissue foci due to spongiosis were observed together with infiltration of inflammatory cells, proliferation of mesenchymal cells, and increase of vimentin positive astrocytes which was significantly different from the control groups. The results suggest that thrombin plays an important role in inflammation, brain edema and reactive gliosis following CNS injury.

Animals↗
PubMed1994

Gamma knife radiosurgery of a series of only minimally selected metastatic brain tumours.

From December 1991 to October 1992, 77 lesions in 25 consecutive patients were treated with Gamma Knife radiosurgery. Thirteen patients (52%) had multiple metastases up to sixteen lesions and twelve patients had a single metastasis. The volume of the largest tumour treated was 12.5 cm3. Karnofsky performance status (KPS) of the patients was 20-90% (mean 70). Marginal tumour dose given was 18 to 35 Gy (mean 26.1 Gy) in 30 to 90% isodose line according to the tumour volume and site. All but two patients were followed by MRI or CT scan repeatedly for a minimum of 6 month or to death. All but one of the tumours were locally controlled. Seventeen patients died during follow up and in four death was due to remote CNS metastases. The median survival for this minimally selected group of patients was 8.5 months, and the median survival for the patients with a single metastasis was 10.5 months. In patients with multiple metastases the median survival reached only 2.5 months but in 11 patients out of 13 patients neurological symptoms and signs improved or stabilized shortly after radiosurgery.

Adult↗
PubMed1994

Penetration injury of the pyramis caused by a kick from a racehorse.

A 56-year-old man presented with an unusual cranial penetration injury due to a horse's hoof. The CT number of the hoof was 269, and thus clearly not that of a wooden fragment or bone. An emergency operation was performed to remove the foreign body. The operation went well, and no infection developed. Eight months later he could walk unaided and had only mild disorientation.

Animals↗
PubMed1994

A clinical and histopathological study of factors affecting MRI signal intensities of pituitary adenomas.

Our aim was to elucidate the factors which determine the MRI signal intensities of pituitary adenomas. We examined 51 patients with surgically-confirmed pituitary adenomas. Using a spin-echo pulse sequence (SE 500/15), coronal and sagittal images (3 mm slices) were obtained. Signal intensities on T1-weighted images were measured in the parenchyma of the adenoma and in normal grey matter. The relative intensity of the adenoma was assessed by calculating the ratio of its signal intensity to that of the normal grey matter of the same patient. Paraffin-embedded sections were used for haematoxylin and eosin staining. The number of cells in a prescribed area was counted, and the mean of five such counts was taken as the cell density. Immunohistochemically stained sections using antibodies for various pituitary hormones were similarly examined; the ratio of the total number of hormone-positive cells to the overall total number of adenoma cells was calculated. Four independent variables were used in the analysis: the age of the patient, the maximum diameter of the adenoma, the cell density and the proportion of hormone-positive cells in the adenoma and, with the signal intensity ratio as the dependent variable, a multiple regression analysis was performed. This revealed that the the greatest influence upon the signal intensities on T1-weighted images was the proportion of hormone positive cells.

Adenoma↗
PubMed1994

Hydrophilic polymer-coated guide wire combined with progressive suppleness pursil catheter for safer, more definitive embolisation of arteriovenous malformations.

For safe, more definitive embolisation of arteriovenous malformations, improved selectivity of the catheter is desirable. This report describes the advantage of the combined use of a progressive suppleness pursil catheter and a hydrophilic polymer-coated guide wire, together with precaution against complications. In 14 patients, 27 vessels were catheterised with this. Chemical embolisation using oestrogen alcohol and polyvinyl acetate was carried out only if sufficiently superselective catheterization was achieved with negative results on a provocation test. Chemical embolisation was successful in 25 vessels, but in three vessels catheterised very distally, it required much more time to withdraw the catheter because of the friction between it and the wall of the vessel.

Adolescent↗
PubMed1994

Primary central nervous system lymphoma in Japan--a retrospective, co-operative study by CNS-Lymphoma Study Group in Japan.

This manuscript reports the results of the first cooperative study on primary central nervous system lymphoma (PCNSL) in Japan. Of 196 patients registered, 170 were judged as having PCNSL. No patients were immunocompromised. Of the 170 patients with PCNSL, 93 were males and 77 were females. The mean was 56.7 years. One hundred and nineteen tumors were confirmed histopathologically, and 51 were diagnosed by neuroimaging alone. All the tumors were non-Hodgkin's lymphoma. According to the Working Formulation for Clinical Usage (WF), 96 out of 119 tumors were classifiable: 53 were diffuse large cell type (55.2%), 17 immunoblastic type (17.7%), 9 diffuse small cleaved type (9.4%), 6 diffuse mixed type (6.3%), 5 polymorphous type (5.2%), 5 small lymphocytic type (5.2%) and 1 small non-cleaved type (1.0%). Of 21 tumors studied immunohistochemically, 18 were B-cell type and 3 were T-cell type. Irradiated patients (144) survived significantly longer than non-irradiated patients, (median survival time, MST: 19.2 and 2.7 months, respectively; p < 0.001). There was a remarkable difference in survival among patients of the intermediate lymphomas; MST (18 months) of patients with large cell lymphoma was significantly shorter than MST (over 96 months) of patients with other intermediate grade lymphomas (small cleaved and mixed) (p < 0.001) and had no significant difference from MST (9 months) of patients with high grade lymphomas. If patients were irradiated with more than 40 Gy, higher doses and different modes of irradiation brought no further survival advantage. Chemotherapy was performed in 87 of 144 irradiated patients (60.4%). No regimens were effective in prolonging survival. Of 144 irradiated patients, a complete or partial response to initial treatment was demonstrated in 91 (63.2%) and 43 patients (29.9%), respectively. Improvement in performance status was confirmed in 82 patients (57.0%). Despite a good response to initial treatments, 88 out of 144 evaluatble patients have died of PCNSL (MST: 19 months). Multivariate analysis based on the Cox hazard model revealed that histology of tumor, age at onset, performance status, and radiotherapy were prognostic factors. Neither chemotherapy nor mode of surgery was a beneficial factor.

Adolescent↗
PubMed1994

Cell death due to ACNU-induced DNA fragmentation: inhibition by cycloheximide.

Several anticancer drugs have recently been shown to induce cell death in a manner similar to programmed cell death or apoptosis. The purpose of this study is to explore the mode of cell death caused by ACNU, a water-soluble nitrosourea. Exposure of rat glioma cell line KEG-1 to ACNU for 2 hours resulted in oligonucleosomal DNA fragmentation, creating a 'ladder' on agarose gel electrophoresis. DNA fragmentation began 18 hours after ACNU treatment, and preceded loss of membrane integrity as evaluated by the trypan blue exclusion test. The extent of DNA fragmentation increased in a dose-dependent manner, and the cell survival rate decreased reciprocally. A translational inhibitor, cycloheximide, suppressed this DNA fragmentation and enhanced cell survival rate with partial inhibition of protein synthesis. However, a transcriptional inhibitor, actinomycin D, failed to inhibit DNA fragmentation or enhance cell survival. Cycloheximide-inhibitable DNA fragmentation was also found in the KEG-1 implanted in vivo rat model following the administration of ACNU. These findings suggest that ACNU induces cell death associates with DNA fragmentation and partially with protein synthesis.

Animals↗
PubMed1994

Magnetic resonance imaging of C2 segmental type of vertebral artery.

Two cases with C2 segmental type of vertebral artery (VA) were reported. One case was a 64-year-old man, who was referred to our hospital suffering from vertigo, ataxia, and right facial palsy. Computed tomography (CT) scan showed multiple lacunae in the basal ganglia bilaterally. Another case was a 47-year-old man, complaining of left hemiparesthesia. A small high density area with a little enhancement was seen in the right parietal region in CT scan, and the lesion was diagnosed as cavernous angioma. Angiography of both cases depicted the vertebral artery not passing through the transverse foramen of the Atlas, but running medioposterior to it, and magnetic resonance imaging (MRI) and CT findings showed the vertebral artery running between the Atlas and Axis, and entering into the spinal canal. In our experience of 1669 sides in 1436 cases, such anomaly of the vertebral artery was found in ten cases including the two abovementioned. Six cases of such anomaly have previously been reported, but demonstration of the VA coursing between Atlas and Axis by MRI has not been published in the literature. During surgical therapy on the upper cervical spine, especially when using a posterior approach, or C1-C2 lateral puncture, the possibility of an anomalous vertebral artery, as in our cases, should be taken into consideration.

Cervical Vertebrae↗
PubMed1994

Primitive trigeminal artery associated with cavernous aneurysm: case report.

A case of unruptured aneurysm at the junction of the cavernous segment of the right internal carotid artery and the primitive trigeminal artery (PTA) is presented. The posterior circulation was not dependent on PTA, thus the PTA was of an adult type in this case. This patient was successfully treated by external carotid artery-anterior temporal artery long vein graft bypass, internal carotid artery ligation at neck, and PTA clipping through the right subtemporal approach. A follow-up angiography showed thrombotic occlusion of the aneurysm. In review of the literature, there are 27 cases reported of PTA aneurysm; among them only 11 cases, including ours, treated surgically. The surgical treatment plan for PTA aneurysm, according to the review of literature is discussed.

Carotid Artery Diseases↗
PubMed1994

Multicentric glioma studied with positron emission tomography: a case report.

Positron emission tomography (PET) studies of a multicentric glioma case were undertaken using 11C-methionine (Met) and 18F-fluorodeoxyuridine (FUdR). Met-PET revealed high accumulating lesion in both the left and right hemispheres, whereas in the FUdR-PET, the lesion on the right showed marked accumulation, but not that on the left. For both foci, the histologic diagnoses were anaplastic astrocytoma, but the lesion on the right showed higher density of undifferentiated tumor cells than that on the left. PET studies using Met and FUdR are effective in delineating the proliferative potential of glioma cells, which otherwise cannot be determined by histopathologic studies.

Brain↗
PubMed1994

Anterior cervical fixation with the titanium locking screw-plate: a preliminary report.

Anterior fixation of cervical spine with screw-plates is gaining in popularity in the management of anterior cervical spine instability. We report on our initial experience with anterior cervical fixation using the titanium locking screw-plate (TLSP). Twelve cases, including cervical trauma, cervical spondylosis, and ossification of the posterior longitudinal ligament (OPLL), underwent multilevel corpectomies or spondylectomies with iliac bone or hydroxylapatite grafting combined with the TLSP system. All 12 patients fused or stabilized with improvement of their neurologic symptoms at a mean follow-up period of 13 months. There were no complications relating to this plating system. Three illustrative cases are presented. Different from previous anterior cervical planting systems such as the Caspar plate, the TLSP system does not gain purchase on the posterior vertebral cortex. It thus reduces possible spinal cord injury during screw placement. The TLSP with interbody fusion may provide reliable stabilization of the cervical spine in a safe and effective manner.

Adult↗
PubMed1994

Molecular cloning of rat cDNA for cytosolic phospholipase A2 and the increased gene expression in the dentate gyrus following transient forebrain ischemia.

Rat cytosolic phospholipase A2 (cPLA2) cDNA was cloned from rat brain. The cDNA showed a high homology of 90% in the nucleotide sequence of the coding region with the human counterpart. By in situ hybridization, the gene expression for cPLA2 was detected in the hippocampus, olfactory bulb, and cerebellar granular cells at very low level of normal rats. The expression was markedly increased in the dentate granule cells of postischemic rat brain. This alteration of the gene expression was discussed in relation to the free fatty acid-mediated neurotoxicity.

Amino Acid Sequence↗
PubMed1994

Induction of c-fos, junB, c-jun, and hsp70 mRNA in cortex, thalamus, basal ganglia, and hippocampus following middle cerebral artery occlusion.

Middle cerebral artery (MCA) occlusion in halothane-anesthetized rats induced c-fos, junB, and c-jun immediate early gene mRNAs and hsp70 heat shock gene mRNA in brain. In situ hybridization studies showed that c-fos and junB were induced throughout all of the cortex at 1 and 4 h following MCA occlusion. hsp70 was induced in the core and margins of the MCA ischemia. By 24 h, there was little expression of c-fos, junB, c-jun, and hsp70 in the core of the MCA infarct; there was modest induction of hsp70 at the margins of the infarct; and there was diffuse induction of c-fos, junB, and c-jun in all of the cortex outside the infarct. MCA occlusion also induced these genes in subcortical structures. c-fos, junB, and hsp70 were induced in ipsilateral medial striatum, most of thalamus including medial and lateral geniculate nuclei, substantia nigra, and hippocampus. Most of these structures, except for the striatum, are not supplied by the MCA. These data show that changes in gene expression can occur in regions remote from an infarction.

Animals↗
PubMed1994

Multiple transcripts of the neurofibromatosis type 1 gene in human brain and in brain tumours.

1. Neurofibromatosis type 1 is a common hereditary disorder characterized by the presence of multiple neurofibromas and café-au-lait spots, and is frequently associated with intellectual handicaps and brain tumours. The gene responsible for neurofibromatosis (the NF1 gene) codes for a protein of 2818 amino acids, termed neurofibromin, which has a domain related to mammalian ras GTPase-activating protein. 2. The NF1 gene gives rise to multiple transcripts generated by alternative splicing, that encode neurofibromin and its isoforms. These include type I mRNA coding for neurofibromin, type II mRNA coding for neurofibromin containing the insertion of 21 amino acids in the GTPase-activating protein-related related domain and mRNA coding for an N-terminal isoform lacking the GTPase-activating protein-related domain (N-isoform). 3. In the present study, the relative levels of mRNAs encoding type I, type II and N-isoform were determined by S1-nuclease mapping analysis in human brain tissue and in primary brain tumours obtained from patients with tumours unrelated to neurofibromatosis type 1. 4. These three mRNAs were expressed in all ten brain tumours and in every region of the brain examined, with the highest levels found in the cerebellum. Type I mRNA was the predominant form in the human brain except for the pons, whereas type II mRNA was predominantly expressed in eight out of ten primary brain tumours. 5. In contrast, N-isoform mRNA was similarly expressed in normal brain tissue and brain tumours. 6. These findings suggest that neurofibromin and its isoforms have important physiological roles in the human brain and that the altered expression of type I and type II mRNAs in brain tumours may be related to the tumorigenesis.

Adult↗
PubMed1994

Infantile spasms with predominantly unilateral cerebral abnormalities.

To investigate the pathogenesis of infantile spasms, 12 children underwent a combination of neurophysiologic and neuroimaging studies including brainstem evoked potentials and single photon emission computed tomography with 99mTcHMPAO. Three of the children had localized cerebral abnormalities on neuroimaging, i.e. right frontotemporal cortical microdysgenesis, left frontotemporal polymicrogyria, and right parietooccipitotemporal porencephalic cyst. Neurophysiologic studies also indicated that a single cerebral hemisphere was predominantly involved, while the other hemisphere and the brainstem were relatively spared, a result compatible with the clinical findings of hemiparesis and hemiconvulsion. In these three patients, administration of carbamazepine was followed by marked improvement of the clinical and electroencephalographic findings. Our results suggest that a combination of noninvasive examinations can distinguish a particular subtype of infantile spasms associated with a localized cerebral abnormality and responsive to carbamazepine.

Carbamazepine↗
PubMed1994

Monitoring of brain tissue haemoglobin concentration and oxygen saturation using a three wavelength spectrophotometric method.

The authors report a new method of monitoring tissue oxygen saturation and haemoglobin concentration simultaneously and continuously using a three-wavelength spectrophotometry. Light emitting diodes were used as light source which made the recording probe small and flexible enough to be placed on the brain surface tightly. Stable and reliable recording of the tissue oxygen saturation and haemoglobin concentration was ascertained in the experimental studies using middle cerebral artery occlusion model of rabbit. In the clinical studies, monitoring during bypass surgery detected rapid changes of local oxygen metabolism and haemoglobin concentration in ischaemic brain. Simultaneous and continuous monitoring of tissue oxygen saturation and haemoglobin concentration enables more practical analysis of brain circulation and oxygen metabolism in experimental and clinical situations.

Adult↗