96 results on '"Kazuhito Takeuchi"'
Search Results
52. Removal of Cavernoma
- Author
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Kazuhito Takeuchi
- Published
- 2021
53. Fully endoscopic combined transsphenoidal and supraorbital keyhole approach for parasellar lesions
- Author
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Jonsu Chu, Tadashi Watanabe, Toshihiko Wakabayashi, Kazuhito Takeuchi, Tetsuya Nagatani, and Yuichi Nagata
- Subjects
Adenoma ,Adult ,Male ,medicine.medical_specialty ,Sphenoid Sinus ,Transsphenoidal approach ,Craniopharyngioma ,03 medical and health sciences ,0302 clinical medicine ,Pituitary adenoma ,medicine.artery ,Humans ,Medicine ,Transcranial approach ,Pituitary Neoplasms ,Aged ,Retrospective Studies ,business.industry ,General Medicine ,Perioperative ,Middle Aged ,medicine.disease ,Combined approach ,Surgery ,Treatment Outcome ,030220 oncology & carcinogenesis ,Neuroendoscopy ,Female ,Internal carotid artery ,business ,Keyhole ,Craniotomy ,030217 neurology & neurosurgery - Abstract
OBJECTIVEParasellar tumors that extend far laterally beyond the internal carotid artery or that are fibrous and adhere firmly to critical structures are difficult to remove totally via the endoscopic transsphenoidal approach alone. In such cases, a combined transsphenoidal-transcranial approach is effective to achieve maximal resection in a single stage. In this paper, a new minimally invasive surgical technique for complicated parasellar lesions, a fully endoscopic combined transsphenoidal–supraorbital keyhole approach, is presented.METHODSA retrospective review of patients who had been treated via a fully endoscopic combined transsphenoidal–supraorbital keyhole approach for complicated parasellar lesions was performed. The data for resection rate, perioperative mortality and morbidity, and postoperative outcomes were analyzed.RESULTSA total of 12 fully endoscopic combined transsphenoidal–supraorbital keyhole approaches were performed from March 2013 to February 2016; 10 were for pituitary adenomas and 2 were for craniopharyngiomas. Gross-total resection or near-total resection was achieved in 7 of 12 cases. Among the 11 patients who had presented with preoperative visual disturbances, 7 had visual improvement. However, 1 patient showed deterioration in visual function. No patient experienced postoperative hemorrhage, needed additional surgical treatment, or had postoperative CSF leakage.CONCLUSIONSIn the combined transsphenoidal and transcranial approach, safe and effective cooperative manipulation with 2 surgical corridors can be performed for complicated parasellar lesions. The goal of this procedure is not to achieve gross-total resection, but to achieve safe resection. Moreover, this new surgical approach offers neurosurgeons a simpler operative field with less invasiveness than the conventional microscopic combined approach. The fully endoscopic combined endonasal–supraorbital keyhole approach is an efficacious procedure for complicated parasellar lesions with acceptable results.
- Published
- 2018
54. A Novel Dissection Method Using a Flexible Neuroendoscope for Resection of Tumors Around the Aqueduct of Sylvius
- Author
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Takayuki Ishikawa, Toshihiko Wakabayashi, Teppei Kawabata, Nobuhiro Tsukamoto, and Kazuhito Takeuchi
- Subjects
Adult ,Male ,medicine.medical_specialty ,03 medical and health sciences ,0302 clinical medicine ,Biopsy ,Humans ,Medicine ,Aged ,Diplopia ,Neurilemoma ,Third ventricle ,medicine.diagnostic_test ,Brain Neoplasms ,Neuroendoscopes ,business.industry ,Cerebral Aqueduct ,Endoscopic third ventriculostomy ,Magnetic resonance imaging ,medicine.disease ,Magnetic Resonance Imaging ,Surgery ,Hydrocephalus ,Dissection ,medicine.anatomical_structure ,030220 oncology & carcinogenesis ,Neuroendoscopy ,Female ,Neurology (clinical) ,medicine.symptom ,business ,030217 neurology & neurosurgery - Abstract
Background: Flexible endoscopes have both a wide range of movement and a wide field of view and are therefore widely used for endoscopic third ventriculostomy and biopsy. However, tumor resection around the aqueduct of Sylvius using flexible endoscopes has scarcely been reported. Case Description: We report 2 cases of tumor resection around the aqueduct of Sylvius. The first case is a 38-year-old man presenting with progressive headache, nausea, and diplopia. Magnetic resonance imaging (MRI) revealed a 1.4 cm nonenhancing mass at the entry of the aqueduct of Sylvius and occlusive hydrocephalus. We performed tumor resection and endoscopic third ventriculostomy (ETV) simultaneously. His symptoms disappeared after the operation. Final pathologic diagnosis was ancient schwannoma. The second case is a 78-year-old woman presenting with progressive disturbance of consciousness (coma). MRI showed 0.7 cm nonenhancing mass at the entry of the aqueduct of Sylvius and occlusive hydrocephalus. We performed tumor resection and ETV similarly. Her consciousness improved after the operation. Final tumor diagnosis was cavernous malformation. In both cases there was no additional neurologic deficit after the surgery. Conclusions: By using a flexible endoscope for tumor dissection, resection of a tumor without a neck, which cannot be removed through aspiration alone, becomes possible. To our knowledge, the presented cases are the first to describe the effectiveness of complete resection of a tumor in the third ventricle using flexible endoscopy., ファイル公開:2019-02-01
- Published
- 2018
55. 11C-methionine- and 18F-FDG-PET double-negative metastatic brain tumor from lung adenocarcinoma with paradoxical high 18F-FDG uptake: A case report.
- Author
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Kuniaki Tanahashi, Masaki Hirano, Lushun Chalise, Takahiko Tsugawa, Yuka Okumura, Tetsunari Hase, Fumiharu Ohka, Kazuya Motomura, Kazuhito Takeuchi, Yuichi Nagata, Norimoto Nakahara, Naozumi Hashimoto, and Ryuta Saito
- Subjects
LUNG tumors ,METASTASIS ,BRAIN tumors ,ADENOCARCINOMA ,BRAIN damage ,LUNG diseases - Abstract
Background: Imaging with
18 F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) and11 C-methionine (MET)-PET can delineate primary and metastatic brain tumors. Lesion size affects the sensitivity of both scans and histopathological features can also influence FDG-PET, but the effects on MET-PET have not been elucidated. Case Description: We report an unusual case of metastatic brain tumors without accumulation of FDG or MET, contrasting with high FDG uptake in the primary lung lesion. The brain lesions were identified as adenocarcinoma with a more mucus-rich background, contributing to the indistinct accumulation of both FDG and MET. Conclusion: Histopathological characteristics can affect both MET and FDG accumulation, leading to findings contradicting those of the primary lesion. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
56. Preservation of Olfactory Function Following Endoscopic Single-Nostril Transseptal Transsphenoidal Surgery
- Author
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Kazuhito Takeuchi, Masaaki Teranishi, Yusuke Sato, Toshihiko Wakabayashi, Masao Tambara, Yuichi Nagata, Takayuki Ishikawa, Jungsu Choo, and Teppei Kawabata
- Subjects
Olfactory system ,Adult ,Male ,Natural Orifice Endoscopic Surgery ,medicine.medical_specialty ,genetic structures ,medicine.medical_treatment ,Tumor resection ,Nose ,Single nostril ,03 medical and health sciences ,Olfaction Disorders ,0302 clinical medicine ,Postoperative Complications ,medicine ,Humans ,Pituitary Neoplasms ,Prospective cohort study ,Aged ,Transsphenoidal surgery ,business.industry ,Postoperative complication ,Middle Aged ,Surgery ,Olfaction test ,Clinical neurology ,030220 oncology & carcinogenesis ,Neuroendoscopy ,Female ,Neurology (clinical) ,business ,030217 neurology & neurosurgery - Abstract
Objective Olfactory dysfunction is a significant postoperative complication related to endoscopic transsphenoidal surgery (TSS). This study aimed to determine the impact of endoscopic TSS on olfactory function. Methods We conducted a prospective study of 32 patients with sellar or parasellar tumors who were treated with endoscopic TSS between December 2013 and October 2016. TSS was performed via a right transseptal approach. We performed the Toyota and Takagi olfactometer test and the venous olfaction test for the evaluation of olfactory function preoperatively and at 1 and 3 months postoperatively. Results The results of the Toyota and Takagi test showed that olfactory function deteriorated in 4 of 32 (12.5%) patients 1 month postoperatively and improved to preoperative baseline levels in all patients 3 months after the procedure. Olfactory function deteriorated in 1 of 31 (3.2%) patients 3 months after the procedure. The venous olfaction test revealed no response in 1 of 31 (3.2%) patients 1 month postoperatively, with no improvement 3 months after the procedure. Conclusions Endoscopic single-nostril transseptal TSS for sellar or parasellar tumor resection has minimal impact on olfactory function.
- Published
- 2019
57. Long‐standing overt ventriculomegaly without aqueductal stenosis: A case report
- Author
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Takashi Tsuboi, Kazuhito Takeuchi, Naoki Atsuta, Haruki Koike, Masahisa Katsuno, and Kazuhiro Ikumi
- Subjects
medicine.medical_specialty ,business.industry ,Endoscopic third ventriculostomy ,medicine.disease ,030218 nuclear medicine & medical imaging ,Hydrocephalus ,03 medical and health sciences ,0302 clinical medicine ,Neurology ,Aqueductal stenosis ,medicine ,Neurology (clinical) ,Radiology ,business ,030217 neurology & neurosurgery ,Ventriculomegaly - Published
- 2017
58. Removal of the Medial Wall of the Cavernous Sinus for Functional Pituitary Adenomas: A Technical Report and Pathologic Significance
- Author
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Teppei Kawabata, Toshihiko Wakabayashi, Takayuki Ishikawa, Taiki Yamamoto, Yuichi Nagata, Yoshie Shimoyama, and Kazuhito Takeuchi
- Subjects
Adenoma ,Adult ,Male ,medicine.medical_specialty ,Blood transfusion ,medicine.medical_treatment ,Blood Loss, Surgical ,Medial wall ,Neurosurgical Procedures ,03 medical and health sciences ,Medial wall–plasty ,0302 clinical medicine ,Postoperative Complications ,Pituitary adenoma ,Acromegaly ,Medicine ,Humans ,Pituitary Neoplasms ,Pituitary ACTH Hypersecretion ,Aged ,Retrospective Studies ,Aged, 80 and over ,Palsy ,business.industry ,Medial wall removal ,Cushing disease ,Endoscopy ,Middle Aged ,medicine.disease ,Occult ,Cushing Disease ,Treatment Outcome ,030220 oncology & carcinogenesis ,Cavernous sinus ,Surgery ,Cavernous Sinus ,Female ,Neurology (clinical) ,Radiology ,Growth Hormone-Secreting Pituitary Adenoma ,business ,030217 neurology & neurosurgery - Abstract
Background: Removal of the medial wall of the cavernous sinus (MW) is challenging for neurosurgeons. We describe a practical method of endoscopic MW removal via endonasal transsphenoidal approach to minimalize intraoperative blood loss and postoperative morbidities. We also present the pathologic significance of this technique for functional pituitary adenomas (FPAs). Methods: We performed MW removal in patients with FPA with no well-defined pseudocapsule and a tumor in direct contact with the MW. The MW was judged to have tumor invasion based on the intraoperative appearance, and it was removed regardless of the appearance of MW involvement. Intraoperative findings and postoperative clinical, endocrinologic, and pathologic outcomes were retrospectively reviewed. Results: Fourteen patients underwent MW removal for FPA, including 12 patients with acromegaly and 2 with Cushing disease. Mean intraoperative blood loss was 170 mL (range, 32–400 mL), and none of the patients required blood transfusion. Among the 7 patients without intraoperative apparent MW involvement, 4 (57.1%) had pathologically confirmed tumor invasion into the MW (occult invasion). Biochemical remission by surgery alone was achieved in 13 patients (92.9%). Transient oculomotor palsy occurred in 1 patient (7.1%). Conclusions: Occult tumor invasion into the MW was often detected in patients with FPA without a well-defined pseudocapsule but in direct contact with the MW. Our technique can enhance the effectiveness of surgery with minimal postoperative morbidities., ファイル公開:2020-06-01
- Published
- 2018
59. TB-03 Newly Established Meningioma Organoid Model Elucidated an Important Role of FOXM1 in Meningioma Progression
- Author
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Kosuke Aoki, Kuniaki Tanahashi, Toshihiko Wakabayashi, Yukihiro Shiraki, Kazuya Motomura, Yotaro Kitano, Shintaro Yamazaki, Sachi Maeda, Hiroyuki Shimizu, Fumiharu Ohka, Junya Yamaguchi, Atsushi Enomoto, Kazuhito Takeuchi, Masaki Hirano, and Atsushi Natsume
- Subjects
Pathology ,medicine.medical_specialty ,Solitary fibrous tumor ,Malignant meningioma ,business.industry ,medicine.medical_treatment ,Cancer ,medicine.disease ,Supplement Abstracts ,nervous system diseases ,Radiation therapy ,Meningioma ,Tumor Biology/Models (TB) ,Benign Meningioma ,otorhinolaryngologic diseases ,Organoid ,AcademicSubjects/MED00300 ,Medicine ,AcademicSubjects/MED00310 ,business ,neoplasms ,Exome sequencing - Abstract
Meningioma is the most frequently occurring intracranial neoplasms in adults. Tumor removal surgery and radiotherapy were the widely accepted standard treatment for meningioma. Most meningioma cases were cured by extended total removal. However, some tumors develop in locations less amenable to resection, resulting in tumor recurrence after incomplete tumor removal followed by radiotherapy. Although several comprehensive studies have revealed frequently found molecular alterations of meningiomas, effective treatment reagents targeting specific molecular alterations have not been identified yet because of limited number of representative research models such as tumor cell lines or animal models of meningiomas. Recently developed 3D culture technologies have led to the development of novel cancer models, termed organoid models, due to their quite high efficiency of establishment. In this study, we established primary organoid culture methods using malignant meningioma cell lines (e.g. HKBMM and IOMM-Lee) and patient-derived meningioma tissues. Using this novel method, we have been able to establish six organoid models (four WHO grade I meningiomas, one WHO grade III one and one solitary fibrous tumor (SFT)) using tumor tissues derived from six consecutive patients with 100% success rate. Histological analyses, whole exome sequencing and copy number analyses revealed that these organoids exhibited consistent histological features and molecular profiling with those of parental tumors. Using public database, we identified upregulated FOXM1 was correlated with increased tumor proliferation. Over-expression of FOXM1 in benign meningioma organoids increased organoid proliferation, while depletion of FOXM1 in malignant ones decreased their proliferation. We revealed that novel organoid model for meningioma enable to shed light on the tumor biology of meningioma.
- Published
- 2020
60. Endoscopic-assisted paramedian infratentorial supracerebellar approach for pineal cyst – How I do it Video clip
- Author
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Ahmed Ansari, Kazuhito Takeuchi, Kento Sasaki, Yasuhiro Yamada, Kyosuke Miyatani, Akihiko Horiguchi, Tsukasa Kawase, Riki Tanaka, and Yoko Kato
- Subjects
Endoscope ,business.industry ,Great saphenous vein ,Video Abstract ,Pineal tumor ,Anatomy ,medicine.disease ,Supracerebellar infratentorial ,Endoscopic assisted ,Paramedian ,Prone position ,medicine.anatomical_structure ,medicine ,Surgery ,Cyst ,Arachnoid Membrane ,Neurology (clinical) ,Internal Occipital Vein ,Vein ,business ,Sinus (anatomy) - Abstract
Background: The endoscopic supracerebellar-infratentorial (SCIT) approach is a viable method to access pathology of the posterior incisura, but a narrow working space and frequent instrument conflict can potentially limit its surgical efficacy. We planned an endoscopic-assisted paramedian infratentorial supracerebellar approach for pineal cyst. Case Description: Patient was placed in prone position under general anesthesia. His head was rotated to the left side slightly. The location of the transverse sinus was detected with navigation system. A 5 cm linear skin incision was performed, and a 2 cm craniectomy was performed about 2 cm left of the median. The transverse sinus was little bit exposed. Dura was incised in a U-shaped incision with the transverse sinus at the base. The endoscope was advanced along with the culmen. At that time, we observed inferior and superior vermian vein. After reaching to the thick arachnoid near by galenic system, the arachnoid membrane was incised and the CSF was evacuated. After that, the cerebellum became soft and the surgical corridor became large. The arachnoid membrane was incised widely. Pineal cyst, precentral cerebellar vein, bilateral internal occipital vein and great vein of galen were exposed. There were some small veins on the pineal cyst, but the adhesion was not so severe. The cyst was dissected from these small veins. There was no adhesion between the cyst and surrounding brain except for the pineal recess. Bilateral ICV was seen behind the cyst. There was feeding artery and draining vein on the antero-lateral part of the cyst. These vessels were coagulated and cut, then the cyst was removed. After the removal, we confirmed complete removal of the cyst and hemostasis. Conclusion: Endoscopic-assisted paramedian SCIT approach for pineal cyst in prone position is a reasonable and efficient access for posterior third ventricular lesions. The learning curve, maneuverability in small space, and instrument conflict limit efficacy.
- Published
- 2020
61. Incidence and risk factors of subdural hematoma after intraoperative cerebrospinal fluid leakage during the transsphenoidal approach
- Author
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Kazuhito Takeuchi, Jonsu Chu, Tetsuya Nagatani, Toshihiko Wakabayashi, Tadashi Watanabe, and Yuichi Nagata
- Subjects
Adult ,Male ,medicine.medical_specialty ,Endocrinology, Diabetes and Metabolism ,medicine.medical_treatment ,Hypopituitarism ,Ventricular system ,Neurosurgical Procedures ,03 medical and health sciences ,Postoperative Complications ,0302 clinical medicine ,Endocrinology ,Hematoma ,Japan ,Risk Factors ,Pituitary adenoma ,medicine ,Humans ,Pituitary Neoplasms ,Intraoperative Complications ,Craniotomy ,Aged ,Retrospective Studies ,Transsphenoidal surgery ,Cerebrospinal Fluid Leak ,business.industry ,Incidence ,Middle Aged ,medicine.disease ,Magnetic Resonance Imaging ,Craniopharyngioma ,Surgery ,Hematoma, Subdural ,030220 oncology & carcinogenesis ,Female ,Tomography, X-Ray Computed ,Complication ,business ,030217 neurology & neurosurgery - Abstract
The transsphenoidal approach (TSA) is regarded as the first line of treatment for sellar and suprasellar lesions. There are only few case reports of postoperative subdural hematoma after TSA and extended transsphenoidal approach (eTSA), and the detailed incidence and risk factors for this complication are still unknown. We reviewed the incidence and risk factors for subdural hematoma after TSA and eTSA. Between January 1, 2013 and December 31, 2014, 165 consecutive patients underwent TSA or eTSA at Nagoya University Hospital and Nagoya Daini Red Cross Hospital. Fifty-one patients experienced intraoperative CSF leakage. Postoperative subdural hematoma was observed in 10 patients, all of whom experienced intraoperative CSF leakage. We reviewed clinical data including CT and MR images and examined factors related to subdural hematoma among patients with intraoperative CSF leakage. In univariate statistical analyses, risk factors for postoperative subdural hematoma were advanced age, high Evans’ index, and preoperative hypopituitarism. These factors were also significant in the multivariate logistic regression analysis. There were no statistical differences in sex, tumor size, approach methods, preoperative diabetes insipidus, or degree of intraoperative CSF leakage. The incidence of postoperative subdural hematoma after intraoperative CSF leakage during TSA and eTSA was higher than the incidence reported in patients after craniotomy. Intraoperative CSF leakage should be avoided as much as possible, especially in patients with brain atrophy and/or enlargement of the ventricular system, even if the intent of the reconstruction technique is authenticity. In addition, patients with hypopituitarism should be carefully followed up after surgery.
- Published
- 2016
62. The 'steppingstone' phenomenon: a new endoscopic finding in slit-ventricle syndrome
- Author
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Tadashi Watanabe, Mihoko Kato, Hirokatsu Osawa, Kazuhito Takeuchi, Toshihiko Wakabayashi, and Yuichi Nagata
- Subjects
medicine.medical_specialty ,Endoscope ,Ventriculoperitoneal Shunt ,Slit Ventricle Syndrome ,03 medical and health sciences ,0302 clinical medicine ,Cerebrospinal fluid ,Internal medicine ,Occlusion ,medicine ,Humans ,business.industry ,Infant ,General Medicine ,Anatomy ,medicine.disease ,Shunt (medical) ,Hydrocephalus ,030220 oncology & carcinogenesis ,Pediatrics, Perinatology and Child Health ,Cardiology ,Female ,Neurology (clinical) ,Neurosurgery ,Headaches ,medicine.symptom ,business ,030217 neurology & neurosurgery - Abstract
Slit-ventricle syndrome (SVS) seems to encompass various pathophysiological abnormalities, including overdrainage of cerebrospinal fluid (CSF) and craniocerebral disproportion after extracranial CSF shunt placement. These pathologies result in small ventricle morphologically, and the ventricular catheter is obstructed by the collapsed ventricular walls. Patients with intermittent headaches, small ventricles on neuroimaging, and slow refill of the shunt reservoir are diagnosed with SVS. In this report, we present a case of SVS treated endoscopically. We detected bulges in a zigzag line on the ventricular walls according to side holes of the ventricular tube, and named them "steppingstone" phenomenon. It is a curious finding which directly shows that the intermittent obstruction of the ventricular tube occurs in patients with SVS. No previous articles have reported this phenomenon, and it indicates adequate treatment for SVS should be provided.
- Published
- 2016
63. Lateral temporal encephaloceles: case-based review
- Author
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Kazuhito Takeuchi, Mihoko Kato, Jonsu Chu, Toshihiko Wakabayashi, and Yuichi Nagata
- Subjects
Adult ,Male ,medicine.medical_specialty ,Meningocele ,Encephalocele ,Pterion ,03 medical and health sciences ,0302 clinical medicine ,Arachnoid cyst ,Pregnancy ,Temporal bone ,medicine ,Deformity ,Humans ,Cyst ,business.industry ,Temporal Bone ,General Medicine ,medicine.disease ,Magnetic Resonance Imaging ,Surgery ,Hydrocephalus ,medicine.anatomical_structure ,030220 oncology & carcinogenesis ,Pediatrics, Perinatology and Child Health ,Asterion ,Female ,Neurology (clinical) ,Radiology ,medicine.symptom ,business ,030217 neurology & neurosurgery - Abstract
Lateral temporal encephalocele is an extremely rare clinical condition, with only 18 cases presented in the literature to date. No review articles have examined lateral temporal encephalocele in depth. We therefore reviewed past cases of lateral encephalocele to clarify the clinical characteristics of this extremely rare deformity. We also present a case of lateral encephalocele with arachnoid cyst which has never been reported in past reports. We identified 8 reports describing 18 cases of lateral temporal encephalocele. We therefore reviewed 19 cases of lateral temporal encephalocele, including our own experience, and discussed the clinical characteristics of this pathology. All the cases with lateral temporal encephalocele were detected at birth except for an occult case. The majority occurred at the pterion, and occurrence at the asterion appears much rarer. Due to the preference for the pterion, the ipsilateral orbital wall was also distorted in some cases. Lateral temporal encephalocele seems to have fewer associated malformations: only 3 cases of lateral temporal encephalocele had associated malformations, including our case which was associated with intracranial arachnoid cyst. The only case of lateral temporal encephalocele to have shown hydrocephalus was our own case. Patients with this deformity have relatively good prognoses: only 3 of the 19 cases showed delayed psychomotor development during follow-up. Provision of adequate treatment is likely to achieve a good prognosis in patients with lateral temporal encephalocele, so we should keep in mind this deformity when encountering pediatric patients with mass lesions on the temporal cranium.
- Published
- 2016
64. Endoscopic Resection of Brain Stem Cavernous Malformations (BSCMs) : Two Illustrative Cases and Surgical Methods Employed
- Author
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Jonsu Chu, Toshihiko Wakabayashi, Tadashi Watanabe, Yuichi Nagata, and Kazuhito Takeuchi
- Subjects
medicine.medical_specialty ,business.industry ,Cavernous malformations ,medicine.disease ,Surgical methods ,03 medical and health sciences ,0302 clinical medicine ,030220 oncology & carcinogenesis ,Medicine ,Surgery ,Endoscopic resection ,Neurology (clinical) ,Radiology ,business ,030217 neurology & neurosurgery - Published
- 2016
65. Extension of Configurational Polyhedra to Finite Temperature Property
- Author
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Kazuhito Takeuchi, Koretaka Yuge, Kazuya Kojima, and Tetsuya Taikei
- Subjects
Physics ,Statistical Mechanics (cond-mat.stat-mech) ,Internal energy ,Thermodynamic equilibrium ,Mathematical analysis ,Lattice (group) ,FOS: Physical sciences ,Disordered Systems and Neural Networks (cond-mat.dis-nn) ,02 engineering and technology ,Condensed Matter - Disordered Systems and Neural Networks ,021001 nanoscience & nanotechnology ,01 natural sciences ,Vertex (geometry) ,Polyhedron ,0103 physical sciences ,Configuration space ,010306 general physics ,0210 nano-technology ,Absolute zero ,Condensed Matter - Statistical Mechanics ,Physical quantity - Abstract
Configurational polyhedora (CP) is a hyperpolyhedra on multidimensional configuration space, whose vertex (and edges) corresponds to upper or lower limit value of correlation functions for all possible atomic configuration on given lattice. In classical systems where physical property including internal energy and elastic modulus can be a linear map for structures considered, it is known that atomic configuration having highest (or lowerst) physical quantity should always locate on one of the vertices at absolute zero temperature. The present study extend the idea of CP to finite-temperature property (especially, focusing on internal energy), and successfully provides demonstration of how temperature dependence of internal energy in equilibrium state for alloys is interpreted in terms of the density of states for non-interacting system along specially selected direction on cofiguration space., 4 figures
- Published
- 2016
66. How I do it: shoelace watertight dural closure in extended transsphenoidal surgery
- Author
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Kazuhito Takeuchi, Tetsuya Nagatani, and Toshihiko Wakabayashi
- Subjects
musculoskeletal diseases ,medicine.medical_specialty ,Cerebrospinal Fluid Rhinorrhea ,medicine.medical_treatment ,Dura mater ,Skull Base Neoplasms ,Neurosurgical Procedures ,Surgical Flaps ,Skull Base Neoplasm ,Fascia lata ,otorhinolaryngologic diseases ,medicine ,Humans ,Skull Base ,Transsphenoidal surgery ,Fibrous joint ,business.industry ,Anatomy ,Surgery ,body regions ,Skull ,medicine.anatomical_structure ,Dura Mater ,Neurology (clinical) ,business - Abstract
Skull base reconstruction after extended transsphenoidal surgery is essential to prevent postoperative cerebrospinal fluid leakage. A novel and simple technique for skull base reconstruction termed “shoelace dural closure” was devised. The dura mater was closed with a fat graft using a continuous running suture with both ends of a double-armed suture. The shoelace dural closure is an effective method for achieving watertight closure of the anterior skull base without the use of lumbar drains, fascia lata grafts, or nasoseptal flaps.
- Published
- 2015
67. Bilateral occlusion of the foramina of Monro after endoscopic third ventriculostomy for aqueductal stenosis—a case report
- Author
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Toshihiko Wakabayashi, Masao Tambara, Tetsuya Nagatani, Yusuke Sato, Kazuhito Takeuchi, Tadashi Watanabe, and Yuichi Nagata
- Subjects
musculoskeletal diseases ,medicine.medical_specialty ,Cerebral Ventricles ,Ventriculostomy ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,Lateral ventricles ,0302 clinical medicine ,Occlusion ,Image Processing, Computer-Assisted ,medicine ,Humans ,Child ,Septum pellucidum ,business.industry ,Endoscopic third ventriculostomy ,General Medicine ,musculoskeletal system ,medicine.disease ,Magnetic Resonance Imaging ,Surgery ,Hydrocephalus ,Cerebrovascular Disorders ,Aqueductal stenosis ,Neuroendoscopy ,Pediatrics, Perinatology and Child Health ,Female ,Neurology (clinical) ,Neurosurgery ,Headaches ,medicine.symptom ,business ,030217 neurology & neurosurgery - Abstract
Bilateral occlusion of the foramina of Monro is an extremely rare clinical condition. We present the case of a 10-year-old girl who complained of frequent headaches. Magnetic resonance imaging showed triventricular hydrocephalus due to aqueductal stenosis, so endoscopic third ventriculostomy was performed successfully. The headaches subsequently disappeared, but the patient presented with exacerbation of headaches 32 months postoperatively. Magnetic resonance imaging demonstrated bilateral hydrocephalus of the lateral ventricles, implying bilateral occlusion of the foramina of Monro. We again performed endoscopic surgery, confirming bilateral occlusion of the foramina of Monro. The foramina of Monro were apparently obstructed by normal ependyma, and no tumor masses or other structures were detected around the foramina, so we diagnosed the occlusion of the foramina as secondary after endoscopic third ventriculostomy. We fenestrated the septum pellucidum using a monopolar micro endoscopic electrode, and a ventriculoperitoneal shunt was placed for the management of hydrocephalus. The postoperative course was uneventful, and the headaches were completely resolved.
- Published
- 2015
68. Determination of Variance for Configurational Density of States in Crystalline Solids
- Author
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Tetsuya Taikei, Kazuhito Takeuchi, and Koretaka Yuge
- Subjects
Materials science ,Density of states ,Thermodynamics ,Variance (accounting) - Published
- 2017
69. Steroid-responsive recurrent tumefactive demyelination with multiple petechial hemorrhages along non-displaced medullary veins
- Author
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Ichiro Nakashima, Masashi Suzuki, Masato Abe, Toshiaki Taoka, Mari Yoshida, Masahisa Katsuno, Kazuhito Takeuchi, Shigeo Ohba, Takashi Ando, Yumiko Harada, Takashi Tsuboi, Fumiharu Ohka, Naoki Atsuta, and Masato Nakaguro
- Subjects
Pathology ,medicine.medical_specialty ,medicine.diagnostic_test ,Medullary cavity ,business.industry ,Treatment outcome ,Magnetic resonance imaging ,General Medicine ,Steroid responsive ,Tumefactive demyelination ,medicine ,Surgery ,Neurology (clinical) ,business - Published
- 2020
70. Quality of Life Changes Before and After Transsphenoidal Surgery for Sellar and Parasellar Lesions
- Author
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Toshihiko Wakabayashi, Yuri Aimi, Tetsuya Nagatani, Eriko Tanemura, Takayuki Ishikawa, Yuichi Nagata, Masao Tambara, Jungsu Choo, and Kazuhito Takeuchi
- Subjects
Adenoma ,Adult ,Male ,medicine.medical_specialty ,SF-36 ,Adolescent ,medicine.medical_treatment ,03 medical and health sciences ,Young Adult ,0302 clinical medicine ,Quality of life ,Pituitary adenoma ,Acromegaly ,medicine ,Humans ,Pituitary Neoplasms ,Postoperative Period ,Aged ,Transsphenoidal surgery ,Aged, 80 and over ,business.industry ,Endoscopy ,Middle Aged ,medicine.disease ,humanities ,Craniopharyngioma ,Surgery ,Treatment Outcome ,030220 oncology & carcinogenesis ,Quality of Life ,Female ,Neurology (clinical) ,General Health Questionnaire ,business ,Body mass index ,030217 neurology & neurosurgery - Abstract
Objective Although reports regarding the relationship between surgical complications and quality of life (QOL) exist, a general consensus regarding this issue is lacking. The aim of this study was to evaluate QOL after endoscopic transsphenoidal approach. Methods We assessed patients with sellar or parasellar lesions that were removed with endoscopic transsphenoidal approach or extended endoscopic transsphenoidal approach between January 2010 and December 2016. 36-Item Short Form Health Survey and 30-Item General Health Questionnaire QOL scores were obtained preoperatively and 1 month and 6 months postoperatively. Results We analyzed 89 patients with nonfunctioning pituitary adenoma (NFPA) and 39 patients with acromegaly. Physical QOL decreased 1 month after surgery but recovered after 6 months in both groups. Mental QOL improved postoperatively compared with preoperatively. Patients with acromegaly had a worse Physical Component Summary (PCS) on 36-Item Short Form Health Survey (48.7, 28.9, and 41.0) at 6 months than patients with NFPA. The low preoperative PCS group did not improve until 6 months postoperatively. Multiple regression analysis revealed the following factors were key to postoperative QOL: age (NFPA PCS 6 months postoperatively; correlation coefficient = −0.489), preoperative Mental Component Summary (MCS) (NFPA MCS 6 months postoperatively, correlation coefficient = 0.573), body mass index (acromegaly PCS 6 months postoperatively; correlation coefficient = −0.376), preoperative PCS (acromegaly PCS 6 months postoperatively; correlation coefficient = 0.905), and preoperative MCS (acromegaly MCS 6 months postoperatively; correlation coefficient = 0.726). Conclusions Endoscopic transsphenoidal approach can improve QOL in patients by 6 months postoperatively. In patients with acromegaly with significant QOL impairments preoperatively, surgery sometimes may be unable to normalize QOL.
- Published
- 2018
71. Neuroendoscopic Cylinder Surgery and 5-Aminolevulinic Acid Photodynamic Diagnosis of Deep-Seated Intracranial Lesions
- Author
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Yusuke Satoh, Tadashi Watanabe, Yuichi Nagata, Fumiharu Ohka, Yugo Kishida, Kazuhito Takeuchi, Atsushi Natsume, Kyozo Kato, Tetsuya Nagatani, Jungsu Choo, and Toshihiko Wakabayashi
- Subjects
Adult ,Male ,medicine.medical_specialty ,Endoscope ,Adolescent ,Biopsy ,Brain tumor ,Astrocytoma ,Lesion ,03 medical and health sciences ,Young Adult ,0302 clinical medicine ,Diffuse Astrocytoma ,medicine ,Humans ,Child ,Aged ,Photosensitizing Agents ,Germinoma ,medicine.diagnostic_test ,Pilocytic astrocytoma ,business.industry ,Brain Neoplasms ,Neuroendoscopes ,Aminolevulinic Acid ,Middle Aged ,medicine.disease ,Surgery ,030220 oncology & carcinogenesis ,Female ,Neurology (clinical) ,medicine.symptom ,business ,Glioblastoma ,030217 neurology & neurosurgery ,Anaplastic astrocytoma - Abstract
Background Microscopic detection of intracranial brain tumors with 5-aminolevulinic acid (5-ALA) has proven extremely useful, and reports the use of 5-ALA have recently increased. However, few reports have described 5-ALA photodynamic diagnosis (PDD) using a neuroendoscope. We performed neuroendoscopic 5-ALA PDD for various brain lesions and present a procedure using only a neuroendoscope. Methods We describe the diagnosis of 20 intracranial brain lesion cases with a 5-ALA–guided fluorescence endoscope. A light-emitting diode that emitted either white light or 400- to 410-nm violet light was attached to a neuroendoscope. We performed cylinder surgery with a transparent sheath under observation with a rigid neuroendoscope. Results Neuroendoscopic biopsies were performed in 11 patients, and resections were performed in 9 patients. All lesions were observed with a neuroendoscope under sequential white light and violet light. We confirmed the presence of a red fluorescent lesion under violet light in 15 patients, including 4 of 5 glioblastoma cases (80%); 1 of 2 anaplastic astrocytoma cases (50%); 4 of 5 diffuse large B cell lymphoma cases (80%); 2 of 2 metastatic brain tumors; 1 of 1 case each of diffuse astrocytoma, pilocytic astrocytoma, inflammatory change, and germinoma (100%); and no cases of anaplastic ependymoma or cysticercosis. Pretargeted lesions were accurately harvested from all biopsy specimens. Gross total resection was achieved in 5 of 9 patients using a resection procedure. Conclusions Our described method offers a promising technique for achieving precise brain tumor biopsies and safe resection.
- Published
- 2017
72. Accurate estimation of a phase diagram from a single STM image
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Shu Kurokawa, Hiroki Saito, Kazuhito Takeuchi, Koretaka Yuge, Akira Sakai, and Shinya Tabata
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Physics ,Multidisciplinary ,Accurate estimation ,Science ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Article ,law.invention ,symbols.namesake ,Ab initio quantum chemistry methods ,law ,0103 physical sciences ,symbols ,Medicine ,Statistical physics ,Scanning tunneling microscope ,010306 general physics ,0210 nano-technology ,Hamiltonian (quantum mechanics) ,CALPHAD ,Phase diagram - Abstract
We propose a new approach to constructing a phase diagram using the effective Hamiltonian derived only from a single real-space image produced by scanning tunneling microscopy (STM). Currently, there have been two main methods to construct phase diagrams in material science: ab initio calculations and CALPHAD with thermodynamic information obtained by experiments and/or theoretical calculations. Although the two methods have successfully revealed a number of unsettled phase diagrams, their results sometimes contradicted when it is difficult to construct an appropriate Hamiltonian that captures the characteristics of materials, e.g., for a system consisting of multiple-scale objects whose interactions are essential to the system’s characteristics. Meanwhile, the advantage of our approach over existing methods is that it can directly and uniquely determine the effective Hamiltonian without any thermodynamic information. The validity of our approach is demonstrated through an Mg–Zn–Y long-period stacking-ordered structure, which is a challenging system for existing methods, leading to contradictory results. Our result successfully reproduces the ordering tendency seen in STM images that previous theoretical study failed to reproduce and clarifies its previously unknown phase diagram. Thus, our approach can be used to clear up contradictions shown by existing methods.
- Published
- 2017
73. A Purely Endoscopic and Simultaneous Transsphenoidal and Transcranial Keyhole Approach for Giant Pituitary Adenoma Resection: A Technical Case Report
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Kazuhito Takeuchi, Tetsuya Nagatani, Tadashi Watanabe, Eriko Okumura, Yusuke Sato, and Toshihiko Wakabayashi
- Subjects
endoscopic surgery ,combined surgery ,transsphenoidal surgery ,Case Report ,pituitary adenoma ,keyhole surgery - Abstract
A combined transsphenoidal-transcranial approach for the resection of pituitary adenomas has previously been reported. While this approach is useful for specific types of pituitary adenomas, it is an invasive technique. To reduce the invasiveness of this approach, we adopted the keyhole concept for pituitary adenoma resection. A 23-year-old man presented at a local hospital with a 6-month history of bilateral hemianopia. Magnetic resonance imaging revealed a large pituitary adenoma extending from the sella turcica toward the right frontal lobe. Endoscopic transsphenoidal surgery was planned at a local hospital; however, the operation was abandoned at the start of the resection because of the firm and fibrous nature of the tumor. The patient was subsequently referred to our hospital for additional surgery. The tumor was removed purely endoscopically via a transsphenoidal and transcranial route. Keyhole craniotomy, 3 cm in diameter, was performed, and a tubular retractor was used to achieve a wider surgical corridor; this enabled better visualization and dissection from the surrounding brain and provided enough room for the use of surgical instruments under endoscopic view. The tumor was successfully removed without complication. This is the first case report to describe the resection of a giant pituitary adenoma using a purely endoscopic and simultaneous transsphenoidal and transcranial keyhole approach.
- Published
- 2015
74. Application of Grid Increment Cluster Expansion to Modeling Potential Energy Surface of Cu-Based Alloys
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Koretaka Yuge, Kazuhito Takeuchi, and Ryohei Tanaka
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Materials science ,Mechanics of Materials ,Mechanical Engineering ,Alloy ,Potential energy surface ,engineering ,Thermodynamics ,General Materials Science ,engineering.material ,Condensed Matter Physics ,Grid ,Cluster expansion - Published
- 2015
75. Trautmann-focused mastoidectomy for a simple, safe presigmoid approach: technical note.
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Kuniaki Tanahashi, Kenji Uda, Yoshio Araki, Kazuhito Takeuchi, Jungsu Choo, Lushun Chalise, Kazuya Motomura, Fumiharu Ohka, Toshihiko Wakabayashi, and Atsushi Natsume
- Published
- 2021
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76. The Multiscope Technique for Microvascular Decompression
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Kazuhito Takeuchi, Yuichi Nagata, Jonsu Chu, Tadashi Watanabe, Toshihiko Wakabayashi, and Tetsuya Nagatani
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Male ,medicine.medical_specialty ,Endoscope ,medicine.medical_treatment ,Endoscopic surgery ,Microvascular decompression ,03 medical and health sciences ,0302 clinical medicine ,Medicine ,Humans ,Hemifacial Spasm ,medicine.diagnostic_test ,business.industry ,Neuroendoscopic surgery ,Middle Aged ,medicine.disease ,Neurovascular bundle ,Endoscopy ,Surgery ,Microvascular Decompression Surgery ,Facial Nerve ,030220 oncology & carcinogenesis ,Neuroendoscopy ,Female ,Neurology (clinical) ,Neurosurgery ,Facial Nerve Diseases ,business ,030217 neurology & neurosurgery ,Hemifacial spasm - Abstract
Background Endoscopic surgery has rapidly become widespread in neurosurgery in recent years. Endoscopy can offer close and panoramic surgical views with fine illumination, even in the deep intracranial area. However, it also has the following serious drawback: an intracranial blind area between the field lens of the endoscope and the site of the dural opening. This blind area cannot be viewed on the endoscopic monitor, and several surgical complications, including accidental intracranial neurovascular structural injury, can occur in this area. In this article, we report a new multiscope surgical technique that can compensate for this serious disadvantage of endoscopic surgery. Methods In the multiscope technique, endoscopic and exoscopic systems are used simultaneously with 2 monitors. Microvascular decompression (MVD) is performed fully endoscopically using an exoscope that compensates for the intracranial blind area of the endoscopic view. Two high-definition monitors for the endoscope and exoscope are placed side-by-side in front of the primary surgeon. Results Two patients with hemifacial spasm were treated by endoscopic MVD with the multiscope technique. In these procedures, fine surgical views were obtained by both the endoscope and exoscope. Two monitors were placed side-by-side in front of the surgeon; as a result, the physician could easily view them simultaneously during the operation. No surgery-related complications occurred. Conclusions The multiscope technique can facilitate the performance of safer neuroendoscopic surgery than conventional endoscopic surgery. This technique can also be adopted in other skull base surgeries, in which the importance of endoscopy is growing.
- Published
- 2016
77. First-principles Study on Formation of LPSO Structures for Ternary Alloys Revisited from Short-range Order
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Kazuhito Takeuchi, Tetsuya Taikei, Koretaka Yuge, Hisashi Miyazono, and Ryohei Tanaka
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Condensed Matter - Materials Science ,Materials science ,Condensed matter physics ,Alloy ,Stacking ,Materials Science (cond-mat.mtrl-sci) ,FOS: Physical sciences ,General Medicine ,engineering.material ,Physical property ,Atomic radius ,Cluster (physics) ,engineering ,Short range order ,Ternary operation - Abstract
We investigate the formation of long-period stacking ordered (LPSO) structure for Mg-Y-Zn ternary alloys based on the short-range order (SRO) tendency of energetically competitive disordered phases. We find that unisotropic SRO tendencies for structures with stacking faults cannot be simply interpreted by arithmetic average of SRO for constituent fcc and hcp stackings, indicating that the SRO should be significantly affected by periodically-introduced stacking faults. We also find that SRO for neighboring Y-Zn pair, which should have positive sign to form specific L12 type cluster found in LPSO, is strongly affected by the distance between stacking faults: e.g., five atomic layer distance does not prefer in-plane Y-Zn pair, while seven atomic layer distance prefer both in- and inter-plane Y-Zn pair. These facts strongly indicate that ordering tendency for the Mg-Y-Zn alloy is significantly dominated by the stacking faults as well as their periodicity. We also systematically investigate correlation between SRO for other Mg-RE-Zn (RE = La, Tb, Dy, Ho, Er) alloys and the physical property of RE elements. We find that while SRO for RE-Zn pair does not show effective correlation with atomic radius, it has strong quadratic correlation with atomic radius considering unisotoropy along in- and inter-plane directions., 4 pages, 3 figures
- Published
- 2016
78. Three types of dural suturing for closure of CSF leak after endoscopic transsphenoidal surgery.
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Takayuki Ishikawa, Kazuhito Takeuchi, Yuichi Nagata, Jungsu Choo, Teppei Kawabata, Tomotaka Ishizaki, and Toshihiko Wakabayashi
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- 2019
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79. A new Wang-Landau approach to obtain phase diagrams for multicomponent alloys
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Koretaka Yuge, Kazuhito Takeuchi, and Ryohei Tanaka
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Condensed Matter - Materials Science ,Computer science ,Materials Science (cond-mat.mtrl-sci) ,FOS: Physical sciences ,01 natural sciences ,010305 fluids & plasmas ,Simple (abstract algebra) ,Present method ,0103 physical sciences ,Density of states ,Statistical physics ,Total energy ,010306 general physics ,Phase diagram - Abstract
We develop an approach to apply Wang-Landau algorithm to multicomponent alloys in semi-grand-canonical ensemble. Although the Wang-Landau algorithm has great advantages over conventional sampling methods, there are few applications to alloys. This is because calculating compositions in semi-grand-canonical ensemble using the Wang-Landau algorithm requires a multi-dimensional density of states in terms of total energy and compositions. However, constructing the multi-dimensional density of states is difficult. In this study, we develop a simple approach to calculate the alloy phase diagram using Wang-Landau algorithm, and show that compositions in semi-grand-canonical ensemble require just some one-dimensional densities of states. Finally, we applied the present method to Cu-Au and Pd-Rh alloys and confirmed that the present method successfully describes the phase diagram with high validity and accuracy., Comment: 6 pages, 6 figures
- Published
- 2016
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80. Quality of life in nonfunctioning pituitary macroadenoma patients before and after surgical treatment
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Tetsuya Nagatani, Kazuhito Takeuchi, Yuri Aimi, Toshihiko Wakabayashi, Yugo Kishida, and Eriko Tanemura
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Adenoma ,Adult ,Male ,Pediatrics ,medicine.medical_specialty ,medicine.medical_treatment ,Quality of life ,Rating scale ,Pituitary adenoma ,Surveys and Questionnaires ,medicine ,Humans ,Pituitary Neoplasms ,Aged ,Transsphenoidal surgery ,medicine.diagnostic_test ,business.industry ,Interventional radiology ,Middle Aged ,medicine.disease ,humanities ,Surgery ,Treatment Outcome ,Quality of Life ,Female ,Neurology (clinical) ,Neurosurgery ,Headaches ,medicine.symptom ,General Health Questionnaire ,business - Abstract
Nonfunctioning pituitary macroadenoma (NFMA) is a benign neoplasm that causes visual function disturbances and headaches and can be treated by transsphenoidal surgery (TSS). It is unclear how quality of life (QOL) changes with surgery and which QOL factors are affected by treatment. The aim is to assess the temporal transition of QOL in NFMA patients undergoing TSS and to identify influential factors. The QOL of NFMA patients who underwent endoscopic TSS was investigated with the short-form 36 (SF-36) health survey questionnaire, general health questionnaire 30 (GHQ30), and numerical rating scale (NRS) of pain at the following three time points: immediately before, 1 month after, and 6 months after surgery. Twenty-four of 30 patients had visual deterioration. The SF-36 baseline value of visual function-impaired NFMA patients was lower than that of the normal population. SF-36 results showed that physical summary scores decreased at 1 month after the operation, but recovered up to the normal population level by 6 months. Mental summary scores generally increased at 1 month after surgery and remained stable until 6 months later. The GHQ30 results were similar to the SF-36 mental summary scores. The strongest factor related to the QOL was visual function. The amount of pain and the necessity of hormonal replacement were also influencing factors. The QOL of NFMA patients is affected both physically and mentally by surgical treatment and symptoms. This QOL assessment is important for planning treatment strategies.
- Published
- 2012
81. Amphiphilic taper-shaped oligomer exhibiting a monolayer smectic A to columnar phase transition
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Yoichi Takanishi, Jun Yamamoto, Kazuhito Takeuchi, and Atsushi Yoshizawa
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chemistry.chemical_classification ,Materials science ,Mesogen ,General Chemistry ,Condensed Matter Physics ,Oligomer ,chemistry.chemical_compound ,Crystallography ,chemistry ,Liquid crystal ,Phase (matter) ,Monolayer ,Amphiphile ,Organic chemistry ,General Materials Science ,Columnar phase ,Alkyl - Abstract
We prepared two series of liquid-crystalline oligomers composed of phenylpyrimidine based mesogenic cores, alkyl spacers and semiperfluorinated alkyl chains in one series and only alkyl chains in the second series. Their physical properties were investigated using optical microscopy, differential scanning calorimetry and X-ray diffraction measurements. The oligomers possessing a semiperfluorinated alkyl chain show a phase sequence of SmC–SmA–Col when the number of phenylpyrimidine moieties was increased. The compound possessing three phenylpyrimidine cores was found to exhibit monolayer SmA and Col phases. On the other hand, the oligomer composed of an alkyl chain and three phenylpyrimidine cores showed only a nematic phase. We discuss effects of the shape amphiphilicity and the hydrocarbon–fluorocarbon amphiphilicity on phase transition behaviour of the amphiphilic oligomers.
- Published
- 2010
82. Grand Projection State: A Single Microscopic State to Determine Free Energy
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Koretaka Yuge, Tetsuya Taikei, Kazuhito Takeuchi, and Tetsuya Kishimoto
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Canonical ensemble ,Physics ,FOS: Physical sciences ,General Physics and Astronomy ,Disordered Systems and Neural Networks (cond-mat.dis-nn) ,02 engineering and technology ,State (functional analysis) ,Condensed Matter - Disordered Systems and Neural Networks ,021001 nanoscience & nanotechnology ,01 natural sciences ,Projection (linear algebra) ,Constraint (information theory) ,Grand canonical ensemble ,symbols.namesake ,Helmholtz free energy ,0103 physical sciences ,symbols ,Statistical physics ,Binary system ,010306 general physics ,0210 nano-technology ,Energy (signal processing) - Abstract
Recently, we clarify connection of spatial constraint and equilibrium macroscopic properties in disordered states of classical system under the fixed composition; namely few special microscopic states, independent of constituent elements, can describe macroscopic properties. In this study, we extend our developed approach to composition-unfixed system. Through this extension in binary system, we discover a single special microscopic state to determine not only composition but also Helmholtz free energy measured from unary system, which has not been described by a single state., Comment: 6 pages, 5 figures
- Published
- 2017
83. Extension of structure integration to magnetic system
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Ryohei Tanaka, Koretaka Yuge, Takashi Ishikawa, and Kazuhito Takeuchi
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Condensed Matter - Materials Science ,Materials science ,Statistical Mechanics (cond-mat.stat-mech) ,Iterative method ,Mechanical Engineering ,Monte Carlo method ,Structure (category theory) ,Materials Science (cond-mat.mtrl-sci) ,FOS: Physical sciences ,Square-lattice Ising model ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Lattice (module) ,Mechanics of Materials ,0103 physical sciences ,Density of states ,A priori and a posteriori ,General Materials Science ,Statistical physics ,010306 general physics ,0210 nano-technology ,Energy (signal processing) ,Condensed Matter - Statistical Mechanics - Abstract
We extend our previously developed method, "structure integration", to evaluate free energy directly for magnetic large systems on given lattice. The present method express the density of states(DOS) as the parameters independent of system but depend on lattice, and replace the DOS unknown a priori as that known a priori. Through two-dimensional square lattice Ising model, we find that the present method can evaluate magnetic free energy efficiently and accurately above critical temperature without iterative method like Monte Carlo simulation., Comment: 4 pages, 4 figures
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- 2015
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84. Theoretical study on density of microscopic states in configuration space via Random Matrix
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Koretaka Yuge, Kazuhito Takeuchi, and Tetsuya Kishimoto
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Physics ,0103 physical sciences ,FOS: Physical sciences ,02 engineering and technology ,Configuration space ,Statistical physics ,Disordered Systems and Neural Networks (cond-mat.dis-nn) ,Condensed Matter - Disordered Systems and Neural Networks ,021001 nanoscience & nanotechnology ,010306 general physics ,0210 nano-technology ,01 natural sciences ,Random matrix - Abstract
In classical systems, our recent theoretical study provides new insight into how spatial constraint on the system connects with macroscopic properties, which lead to universal representation of equilibrium macroscopic physical property and structure in disordered states. These important characteristics rely on the fact that statistical interdependence for density of microscopic states (DOMS) in configuration space appears numerically vanished at thermodynamic limit for a wide class of spatial constraints, while such behavior of the DOMS is not quantitatively well-understood so far. The present study theoretically address this problem based on the Random Matrix with Gaussian Orthogonal Ensemble, where corresponding statistical independence is mathematically guaranteed. Using the generalized Ising model, we confirm that lower-order moment of density of eigenstates (DOE) of covariance matrix of DOMS shows asymptotic behavior to those for Random Matrix with increase of system size. This result supports our developed theoretical approach, where equilibrium macroscopic property in disordered states can be decomposed into individual contribtion from each generalized coordinate with the sufficiently high number of constituents in the given system, leading to representing equilibrium macroscopic properties by a few special microscopic states.
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- 2015
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85. Endoscopic clipping of intraventricular aneurysms using the "wet-field" technique.
- Author
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Kazuhito Takeuchi, Takashi Handa, Jonsu Chu, Kentaro Wada, and Toshihiko Wakabayashi
- Published
- 2019
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86. Direct evaluation of free energy for large system through structure integration approach
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Koretaka Yuge, Ryohei Tanaka, and Kazuhito Takeuchi
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Physics ,Condensed Matter - Materials Science ,Present method ,Lattice (order) ,Materials Science (cond-mat.mtrl-sci) ,FOS: Physical sciences ,General Materials Science ,Statistical physics ,Direct evaluation ,Condensed Matter Physics - Abstract
We propose a new approach, "structure integration", enabling direct evaluation of configurational free energy for large systems. The present approach is based on the statistical information of lattice. Through first-principles-based simulation, we find that the present method not only evaluates configurational free energy accurately in disorder states above critical temperature but also clarify importance of lattice to determine configurational free energy at high temperature., Comment: 4 pages, 5 figures
- Published
- 2014
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87. Fully endoscopic combined transsphenoidal and supraorbital keyhole approach for parasellar lesions.
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Yuichi Nagata, Tadashi Watanabe, Tetsuya Nagatani, Kazuhito Takeuchi, Jonsu Chu, and Toshihiko Wakabayashi
- Published
- 2018
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88. Cerebral Infarction and Subarachnoid Hemorrhage Caused by Central Nervous System Aspergillus Infection
- Author
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Yoshio Araki, Sho Okamoto, Kazuhito Takeuchi, Toshihiko Wakabayashi, Takashi Izumi, and Shinsuke Muraoka
- Subjects
Male ,0301 basic medicine ,medicine.medical_specialty ,Subarachnoid hemorrhage ,030106 microbiology ,Antifungal drug ,Aspergillosis ,Diagnosis, Differential ,03 medical and health sciences ,Central Nervous System Infections ,0302 clinical medicine ,Aneurysm ,medicine ,Humans ,Cerebral infarction ,business.industry ,Glasgow Outcome Scale ,Intracranial Aneurysm ,Cerebral Infarction ,Middle Aged ,Subarachnoid Hemorrhage ,medicine.disease ,Surgery ,Treatment Outcome ,Neurology (clinical) ,Differential diagnosis ,business ,030217 neurology & neurosurgery ,Aspergilloma - Abstract
Background The mortality rate of central nervous system (CNS) Aspergillus infection is >90%. Most cases with ruptured aneurysmal formation resulting from CNS aspergilloma invasion into the arterial wall are difficult to treat with surgical therapy, antifungal drugs, or steroid administration. There is no established therapy for ruptured Aspergillus aneurysms. Both a standardized examination for the diagnosis of CNS aspergillosis and effective treatment of ruptured Aspergillus aneurysms are needed. Case Description A 56-year-old man developed prolonged fever and headache. Magnetic resonance imaging showed a mass lesion around the brainstem. No laboratory data were suspicious for inflammatory diseases or autoimmune diseases. Considering the invasiveness of a surgical approach, we initiated steroid pulse therapy to confirm whether the mass would shrink before biopsy or resection for definitive pathologic diagnosis. Cerebral infarction and subarachnoid hemorrhage occurred almost concurrently just after steroid therapy. We first performed decompression surgery to treat the elevated intracranial hypertension. The specimen taken from the mass lesion at the time of surgery showed CNS Aspergillus fungal forms. Endovascular treatment of the ruptured aneurysm was performed, and medical therapy with an antifungal drug was started. After the Aspergillus infection was well controlled, the patient was discharged. Glasgow Outcome Scale score at discharge was 3. Conclusions Although most patients with ruptured Aspergillus aneurysm have poor outcomes as reported in the literature, this patient's clinical course and outcome were good. Early recognition of CNS aspergillosis and timely surgical intervention to control the vascular event can improve the prognosis for these patients.
- Published
- 2016
89. Interlayer interactions induced by amphiphilicities of a rod-like molecule produce frustrated structures in conventional calamitic phases
- Author
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Kazuhito Takeuchi, Atsushi Yoshizawa, Yoichi Takanishi, Ayumi Nishizawa, and Jun Yamamoto
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Crystallography ,Materials science ,Optical microscope ,law ,Materials Chemistry ,Molecule ,Physical and Theoretical Chemistry ,Surfaces, Coatings and Films ,law.invention - Abstract
We prepared a rod-like molecule, 4-[4-(7-hydroxyheptyloxy)phenyl]-1-(4-hexylphenyl)-2,3-difluorobenzene, and investigated its physical properties using polarized optical microscopy (POM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). The compound was found to exhibit nematic, smectic A, and smectic C phases. A smectic-like layer ordering was detected using XRD at low temperatures of the nematic phase. The nematic phase changed to a smectic A phase when cooled, with no accompanying enthalpy change. Analyses using XRD and POM revealed that the smectic C phase consists of three states: conventional SmC with a monolayered structure, monolayered SmC' possessing an additional weak bilayered character, and SmC'' possessing both monolayered and bilayered structures. Furthermore, a discontinuous increase in birefringence of a homeotropically aligned sample of the compound was observed in the SmC'' phase. Interlayer interactions organized by hydrophobic-hydrophilic amphiphilicity and orthogonal-tilt amphiphilicity are discussed to explain the appearance of the unusual liquid-crystalline phases with a hierarchical structure.
- Published
- 2010
90. Usage of granulocyte colony-stimulating factor every 2 days is clinically useful and cost-effective for febrile neutropenia during early courses of chemotherapy
- Author
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Hisaharu Shikata, Kazuhito Takeuchi, Yoshihiro Yakushijin, Hiroshi Narumi, Masaki Yasukawa, Takaaki Hato, Ikue Takaoka, Jun Yamanouchi, Taichi Azuma, and Tamami Horikawa
- Subjects
Male ,medicine.medical_specialty ,Neutropenia ,Fever ,Neutrophils ,medicine.medical_treatment ,Cost-Benefit Analysis ,Granulocyte ,Drug Administration Schedule ,Lenograstim ,Surgical oncology ,Internal medicine ,Antineoplastic Combined Chemotherapy Protocols ,Granulocyte Colony-Stimulating Factor ,medicine ,Leukocytes ,Humans ,In patient ,Intensive care medicine ,Cyclophosphamide ,Aged ,Chemotherapy ,Antibiotics, Antineoplastic ,business.industry ,Hematology ,General Medicine ,Middle Aged ,medicine.disease ,Chemotherapy regimen ,Recombinant Proteins ,Granulocyte colony-stimulating factor ,medicine.anatomical_structure ,Oncology ,Doxorubicin ,Vincristine ,Prednisone ,Surgery ,Female ,Cost benefit ,Lymphoma, Large B-Cell, Diffuse ,business ,Febrile neutropenia - Abstract
In order to analyze the clinical activity and cost-effectiveness of granulocyte colony-stimulating factors (G-CSF), the prophylactic usage of G-CSF in patients treated with a single chemotherapy regimen during early courses was prospectively evaluated.Thirty patients with newly diagnosed non-Hodgkin lymphoma (NHL) treated with the first course of an R-CHOP regimen were enrolled randomly. After treatment with the first course of chemotherapy, a daily dose of G-CSF (lenograstim, 100 μg) was administered to half (15 cases) of the patients, and a dose of G-CSF (100 μg) was administered every other day to the other half of the patients when leukocytopenia (1.5 × 10(9)/L) and/or neutropenia (0.5 × 10(9)/L) occurred. Changes in leukocyte and neutrophil counts, prophylaxis, febrile neutropenia (FN) events, and cost performance between the two groups were analyzed.No significant difference between the two groups was observed in recoveries of leukocyte and neutrophil counts and evidence of FN. The only difference was the total cost of G-CSF.We concluded that every-other-day use of G-CSF was as clinically effective for the prophylaxis of FN as the daily use of G-CSF, and economically speaking, the administration of G-CSF every other day should be more beneficial for patients with NHL during early courses of R-CHOP chemotherapy.
- Published
- 2010
91. ChemInform Abstract: Biological Activity of Some Cyanobiphenyl Derivatives
- Author
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Masanobu Sagisaka, Ikuo Kashiwakura, Yuuka Takahashi, Masaharu Hazawa, Kazuhito Takeuchi, Kenji Takahashi, Ayumi Nishizawa, and Atsushi Yoshizawa
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Biphenyl ,chemistry.chemical_compound ,Homologous series ,Liquid crystal ,Chemistry ,Stereochemistry ,organic chemicals ,Phase (matter) ,Amphiphile ,heterocyclic compounds ,Biological activity ,General Medicine ,humanities - Abstract
We investigated biological activity of a homologous series of 4-cyano-4′-(ω-hydroxyalkyloxy)biphenyl. The amphiphilic compounds with a nematic phase were found to exhibit marked inhibition of cell ...
- Published
- 2009
92. Biological Activity of Some Cyanobiphenyl Derivatives
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Ayumi Nishizawa, Yuuka Takahashi, Masaharu Hazawa, Atsushi Yoshizawa, Ikuo Kashiwakura, Kazuhito Takeuchi, Kenji Takahashi, and Masanobu Sagisaka
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Biphenyl ,Stereochemistry ,organic chemicals ,Cell ,Biological activity ,General Chemistry ,humanities ,Homologous series ,chemistry.chemical_compound ,medicine.anatomical_structure ,chemistry ,Liquid crystal ,Phase (matter) ,Amphiphile ,medicine ,heterocyclic compounds - Abstract
We investigated biological activity of a homologous series of 4-cyano-4′-(ω-hydroxyalkyloxy)biphenyl. The amphiphilic compounds with a nematic phase were found to exhibit marked inhibition of cell ...
- Published
- 2009
93. Endoscopic-assisted paramedian infratentorial supracerebellar approach for pineal cyst - How I do it Video clip.
- Author
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Riki Tanaka, Kazuhito Takeuchi, Ansari, Ahmed, Kento Sasaki, Kyosuke Miyatani, Yasuhiro Yamada, Tsukasa Kawase, Yoko Kato, and Akihiko Horiguchi
- Subjects
VIDEO excerpts ,GENERAL anesthesia ,VEINS ,CEREBELLUM - Abstract
Background: The endoscopic supracerebellar-infratentorial (SCIT) approach is a viable method to access pathology of the posterior incisura, but a narrow working space and frequent instrument conflict can potentially limit its surgical efficacy. We planned an endoscopic-assisted paramedian infratentorial supracerebellar approach for pineal cyst. Case Description: Patient was placed in prone position under general anesthesia. His head was rotated to the left side slightly. The location of the transverse sinus was detected with navigation system. A 5 cm linear skin incision was performed, and a 2 cm craniectomy was performed about 2 cm left of the median. The transverse sinus was little bit exposed. Dura was incised in a U-shaped incision with the transverse sinus at the base. The endoscope was advanced along with the culmen. At that time, we observed inferior and superior vermian vein. After reaching to the thick arachnoid near by galenic system, the arachnoid membrane was incised and the CSF was evacuated. After that, the cerebellum became soft and the surgical corridor became large. The arachnoid membrane was incised widely. Pineal cyst, precentral cerebellar vein, bilateral internal occipital vein and great vein of galen were exposed. There were some small veins on the pineal cyst, but the adhesion was not so severe. The cyst was dissected from these small veins. There was no adhesion between the cyst and surrounding brain except for the pineal recess. Bilateral ICV was seen behind the cyst. There was feeding artery and draining vein on the antero-lateral part of the cyst. These vessels were coagulated and cut, then the cyst was removed. After the removal, we confirmed complete removal of the cyst and hemostasis. Conclusion: Endoscopic-assisted paramedian SCIT approach for pineal cyst in prone position is a reasonable and efficient access for posterior third ventricular lesions. The learning curve, maneuverability in small space, and instrument conflict limit efficacy. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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94. Interlayer Interactions Induced by Amphiphilicities of a Rod-Like Molecule Produce Frustrated Structures in Conventional Calamitic Phases.
- Author
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Atsushi Yoshizawa, Ayumi Nishizawa, Kazuhito Takeuchi, Yoichi Takanishi, and Jun Yamamoto
- Published
- 2010
- Full Text
- View/download PDF
95. New Wang-Landau approach to obtain phase diagrams for multicomponent alloys.
- Author
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Kazuhito Takeuchi, Ryohei Tanaka, and Koretaka Yuge
- Subjects
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PHASE diagrams , *MULTIPHASE flow , *WANG-Landau algorithm - Abstract
We develop an approach to apply the Wang-Landau algorithm to multicomponent alloys in a semi-grand-canonical ensemble. Although the Wang-Landau algorithm has great advantages over conventional sampling methods, there are few applications to alloys. This is because calculating compositions in a semi-grand-canonical ensemble via the Wang-Landau algorithm requires a multidimensional density of states in terms of total energy and compositions, and constructing it is difficult from the viewpoints of both implementation and computational cost. In this study, we develop a simple approach to calculate the alloy phase diagram based on the Wang-Landau algorithm, and show that a number of one-dimensional densities of states could lead to compositions in a semi-grand-canonical ensemble as a multidimensional density of states could. Finally, we apply the present method to Cu-Au and Pd-Rh alloys and confirm that the present method successfully describes the phase diagram with high efficiency, validity, and accuracy. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
96. Direct evaluation of free energy for large system through structure integration approach.
- Author
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Kazuhito Takeuchi, Ryohei Tanaka, and Koretaka Yuge
- Published
- 2015
- Full Text
- View/download PDF
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