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Search Results: 1 - 10 of 2639 matches for " Yuji Ishikawa "
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Eosinophilic Granuloma Arising from the Sacrum: A Case Report  [PDF]
Yuji Kasukawa, Naohisa Miyakoshi, Michio Hongo, Shigeru Ando, Yoshinori Ishikawa, Yoichi Shimada
Open Journal of Orthopedics (OJO) , 2011, DOI: 10.4236/ojo.2011.12002
Abstract: Introduction: Osseous eosinophilic granulomas commonly occur in the skull, pelvis, vertebrae, mandible, and ribs. However, the eosinophilic granuloma in the sacrum is rare. Case presentation: We present the case of a 13-year-old Japanese boy, who presented with left low-back pain, and was diagnosed with eosinophilic granuloma arising in the sacrum. Computed tomography (CT) and magnetic resonance imaging demonstrated an osteolytic lesion with interruption of the cortex, and signal intensity changes at the left sacral body and wing. Histologic examination indicated an eosinophilic granuloma. Two years after CT-guided biopsy, the tumor had spontaneously healed completely, with no residual pain.Conclusion: The present case was eosiophilic granuloma arising from the rare site of sacrum. The tumor was completely remodeled two years after biopsy.
Pediatric Primary Malignant Lymphoma of the Spine: A Case Report  [PDF]
Daisuke Kudo, Naohisa Miyakoshi, Michio Hongo, Yuji Kasukawa, Yoshinori Ishikawa, Hiroshi Aonuma, Yoichi Shimada
Open Journal of Orthopedics (OJO) , 2012, DOI: 10.4236/ojo.2012.23017
Abstract: Background: Cases of primary malignant lymphomas of the bone are rare and account for about <1% of all lymphomas and 5% of extranodal non-Hodgkin’s lymphomas. Furthermore, most reports have described the occurrence of this disease in the middle-aged population, pediatric malignant lymphomas originating in the bone, particularly in the spine is rare. Methods: A 10-year-old boy presented with low back pain caused by T12 vertebral compression fracture due to sustaining a fall. A month later, he still presented with prolonged low back pain that intensified after exercise. A neoplastic lesion in T12 vertebral body was identified after spine computed tomography (CT) and magnetic resonance imaging. Results: We performed CT-guided biopsy, and he was diagnosed with primary malignant lymphoma of the vertebral body. He was treated with multiagent chemotherapy without irradiation, and complete remission was maintained at the 5-year follow-up. Moreover, the height of the deformed vertebral body improved as he grew. Conclusions: Herein, we report a rare case of pediatric primary malignant lymphoma of the spine with successful clinical and radiological outcome.
RY-Coding and Non-Homogeneous Models Can Ameliorate the Maximum-Likelihood Inferences From Nucleotide Sequence Data with Parallel Compositional Heterogeneity
Sohta A. Ishikawa, Yuji Inagaki, and Tetsuo Hashimoto
Evolutionary Bioinformatics , 2012, DOI: 10.4137/EBO.S9017
Abstract: In phylogenetic analyses of nucleotide sequences, ‘homogeneous’ substitution models, which assume the stationarity of base composition across a tree, are widely used, albeit individual sequences may bear distinctive base frequencies. In the worst-case scenario, a homogeneous model-based analysis can yield an artifactual union of two distantly related sequences that achieved similar base frequencies in parallel. Such potential difficulty can be countered by two approaches, ‘RY-coding’ and ‘non-homogeneous’ models. The former approach converts four bases into purine and pyrimidine to normalize base frequencies across a tree, while the heterogeneity in base frequency is explicitly incorporated in the latter approach. The two approaches have been applied to real-world sequence data; however, their basic properties have not been fully examined by pioneering simulation studies. Here, we assessed the performances of the maximum-likelihood analyses incorporating RY-coding and a non-homogeneous model (RY-coding and non-homogeneous analyses) on simulated data with parallel convergence to similar base composition. Both RY-coding and non-homogeneous analyses showed superior performances compared with homogeneous model-based analyses. Curiously, the performance of RY-coding analysis appeared to be significantly affected by a setting of the substitution process for sequence simulation relative to that of non-homogeneous analysis. The performance of a non-homogeneous analysis was also validated by analyzing a real-world sequence data set with significant base heterogeneity.
RY-Coding and Non-Homogeneous Models Can Ameliorate the Maximum-Likelihood Inferences From Nucleotide Sequence Data with Parallel Compositional Heterogeneity
Sohta A. Ishikawa,Yuji Inagaki,Tetsuo Hashimoto
Evolutionary Bioinformatics , 2012,
Abstract:
Multineuronal spike sequences repeat with millisecond precision
Koki Matsumoto,Tomoe Ishikawa,Yuji Ikegaya
Frontiers in Neural Circuits , 2013, DOI: 10.3389/fncir.2013.00112
Abstract: Cortical microcircuits are nonrandomly wired by neurons. As a natural consequence, spikes emitted by microcircuits are also nonrandomly patterned in time and space. One of the prominent spike organizations is a repetition of fixed patterns of spike series across multiple neurons. However, several questions remain unsolved, including how precisely spike sequences repeat, how the sequences are spatially organized, how many neurons participate in sequences, and how different sequences are functionally linked. To address these questions, we monitored spontaneous spikes of hippocampal CA3 neurons ex vivo using a high-speed functional multineuron calcium imaging (fMCI) technique that allowed us to monitor spikes with millisecond resolution and to record the location of spiking and non-spiking neurons. Multineuronal spike sequences (MSSs) were overrepresented in spontaneous activity compared to the statistical chance level. Approximately 75% of neurons participated in at least one sequence during our observation period. The participants were sparsely dispersed and did not show specific spatial organization. The number of sequences relative to the chance level decreased when larger time frames were used to detect sequences. Thus, sequences were precise at the millisecond level. Sequences often shared common spikes with other sequences; parts of sequences were subsequently relayed by following sequences, generating complex chains of multiple sequences.
One Case of Suspected Angiostenosis Revealed by MRA Following Carotid Endarterectomy Due to a Rare Cause  [PDF]
Yuji Endo, Naoki Sato, Hidekazu Takahashi, Mamoru Ota, Toshihito Ishikawa, Katsuhiro Endo, Kenichi Ebihara
Open Journal of Modern Neurosurgery (OJMN) , 2018, DOI: 10.4236/ojmn.2018.83023
Abstract: We herein report on a case in which magnetic resonance angiography (MRA) following carotid endarterectomy revealed the appearance of angiostenosis due to an artifact of metallic powder, which was thought to have come from an old surgical instrument. The patient was a 77-year-old male. Carotid endarterectomy (CEA) was performed for stenosis in the internal carotid artery of his left neck (82%). Upon observing a decline in renal function following CEA surgery, a postoperative cervical MRA revealed the appearance of high-grade stenosis at the common carotid artery on which surgery was performed. No stenosis was revealed upon carotid ultrasonography and angiography. In the original MRA image, an orbicular low intensity area was observed in concordance with the narrow segment. 3D computed tomography (3D-CT) revealed a metallic finding, suggesting it was an artifact caused by metal powder. Close inspection of the metal surgical instruments used during surgery revealed slight damage to a suture snare which had been used for 30 years. Going forward, it is necessary to pay attention to old surgical instruments, introduce a system by which the number of years and the frequency of use of each surgical instrument can be learned, and replace them with new equipment as necessary.
Prevalence, Spinal Alignment, and Mobility of Lumbar Spinal Stenosis with or without Chronic Low Back Pain: A Community-Dwelling Study
Naohisa Miyakoshi,Michio Hongo,Yuji Kasukawa,Yoshinori Ishikawa,Yoichi Shimada
Pain Research and Treatment , 2011, DOI: 10.1155/2011/340629
Abstract: Although lumbar spinal stenosis (LSS) occurs almost universally with aging, little is known regarding its actual prevalence and relationships to chronic low back pain (CLBP) in the general population. The presence of CLBP in subjects with LSS may have negative impacts on spinal alignment and mobility. This study evaluated the prevalence of LSS using a self-administered, self-reported history questionnaire in 630 community-dwelling individuals ≥50 years old. Subjects with LSS were further divided into LSS+CLBP and LSS alone groups, and spinal alignment and mobility were compared using a computer-assisted device. Prevalence of LSS was 10.8% in this cohort. Subjects in the LSS+CLBP group ( ) showed a significantly more kyphotic lumbar spinal alignment with limited lumbar extension ( ), resulting in a stooped trunk compared to subjects in the LSS alone group ( ). However, no significant difference in spinal mobility was seen between groups. 1. Introduction Low back pain (LBP) is a primarily cited condition among problems linked to postural imbalance [1, 2]. Recurrent or chronic LBP (CLBP) is estimated to occur in 35–79% of patients [3, 4]. Particularly in older individuals, CLBP is at least partially related to degenerative changes associated with aging [5]. The degenerative process (spondylosis) involves the intervertebral discs, facet joints, vertebral bodies, and spinal ligaments. These spondylotic changes often induce lumbar spinal stenosis (LSS). LSS is a well-recognized spinal disorder that commonly affects older adults. The pain and disability associated with degenerative LSS represent a substantial and growing health problem among the elderly [6, 7]. Clinically symptomatic LSS occurs when compression of the nerve roots or cauda equina causes pain, numbness, and tingling, or weakness in the lower extremities. With progressive compression, ambulation may be severely affected (neurogenic claudication). Although LSS has been widely studied in the clinical setting, particularly for surgical cases, few population-based studies have been attempted [8]. In addition, the association between LSS and CLBP remains unclear. Spinal alignment and mobility are important factors for spinal function. Loss of lumbar lordosis correlates well with the incidence of CLBP in adults [9, 10]. Patients with a less mobile spine may show more severe symptoms. However, to the best of our knowledge, no previous community-based studies have assessed spinal alignment and mobility in subjects with LSS with or without CLBP. The objectives of this study were thus (1) to determine the
Sex-Linked Pheromone Receptor Genes of the European Corn Borer, Ostrinia nubilalis, Are in Tandem Arrays
Yuji Yasukochi,Nami Miura,Ryo Nakano,Ken Sahara,Yukio Ishikawa
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0018843
Abstract: Tuning of the olfactory system of male moths to conspecific female sex pheromones is crucial for correct species recognition; however, little is known about the genetic changes that drive speciation in this system. Moths of the genus Ostrinia are good models to elucidate this question, since significant differences in pheromone blends are observed within and among species. Odorant receptors (ORs) play a critical role in recognition of female sex pheromones; eight types of OR genes expressed in male antennae were previously reported in Ostrinia moths.
Recovery of increased signal intensity of the cervical cord on magnetic resonance imaging after surgery for spontaneous spinal epidural hematoma causing hemiparesis
Ishikawa Eiichi,Saito Atsushi,Kujiraoka Yuji,Matsumura Akira
Neurology India , 2008,
Abstract:
Posteriorly migrated thoracic disc herniation: a case report
Miyakoshi Naohisa,Hongo Michio,Kasukawa Yuji,Ishikawa Yoshinori
Journal of Medical Case Reports , 2013, DOI: 10.1186/1752-1947-7-41
Abstract: Introduction Posterior epidural migration of thoracic disc herniation is extremely rare but may occur in the same manner as in the lumbar spine. Case presentation A 53-year-old Japanese man experienced sudden onset of incomplete paraplegia after lifting a heavy object. Magnetic resonance imaging revealed a posterior epidural mass compressing the spinal cord at the T9-T10 level. The patient underwent emergency surgery consisting of laminectomy at T9-T10 with right medial facetectomy, removal of the mass lesion, and posterior instrumented fusion. Histological examination of the mass lesion yielded findings consistent with sequestered disc material. His symptoms resolved, and he was able to resume walking without a cane 4 weeks after surgery. Conclusions Pre-operative diagnosis of posterior epidural migration of herniated thoracic disc based on magnetic resonance imaging alone may be overlooked, given the rarity of this pathology. However, this entity should be considered among the differential diagnoses for an enhancing posterior thoracic extradural mass.
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