Toru Itakura

Tokyo Women's Medical University, Edo, Tokyo, Japan

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Publications (344)556.64 Total impact

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    ABSTRACT: Background Aneurysm formation after stereotactic irradiation of skull base tumors is rare. The formation and rupture of an internal carotid artery (ICA) aneurysm in a patient with skull base Ewing sarcoma/primitive neuroectodermal tumor (PNET), who underwent surgery followed by multiple courses of intensity-modulated radiation therapy (IMRT) and chemotherapy, is described. Case Description A 25-year-old man presented with a sinonasal tumor with intraorbital and intracranial growth. At that time cerebral angiography did not reveal any vascular abnormalities. The lesion was resected subtotally. Histopathologic diagnosis was Ewing sarcoma/PNET. The patient underwent multiple courses of chemotherapy and three courses of IMRT at 3, 28, and 42 months after initial surgery. The total biologically effective dose delivered to the right ICA was 220.2 Gy. Seven months after the third IMRT, the patient experienced profound nasal bleeding that resulted in hypovolemic shock. Angiography revealed a ruptured right C4–C5 aneurysm and irregular stenotic changes of the ICA. Lifesaving endovascular trapping of the right ICA was done. The patient recovered well after surgery but died due to tumor recurrence 6 months later. Conclusion Excessive irradiation of the ICA may occasionally result in aneurysm formation, which should be borne in mind during stereotactic irradiation of malignant skull base tumors.
    Full-text · Article · Dec 2013 · Journal of Neurological Surgery
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    ABSTRACT: Objective: Results of Gamma Knife radiosurgery (GKS) were retrospectively evaluated in 16 patients with histologically confirmed atypical and anaplastic intracranial meningiomas. Materials and methods: There were nine men and seven women (mean age 61.0 years). Atypical meningiomas were diagnosed in nine cases and anaplastic meningiomas in seven. In nine patients there was malignant transformation of a tumor that had initially proved to be benign. In total, 21 radiosurgical procedures were performed. The mean tumor volume at the time of GKS was 7.1 cm3. The mean marginal and maximum irradiation doses were 18.8 and 37.0 Gy, respectively. The mean length of follow-up after treatment was 37.1 months. Findings: Of 21 radiosurgical procedures, 6 (29 %) led to stabilization of tumor growth during the mean follow-up of 40.5 months. It was significantly associated with small lesion volume (P = 0.02), and greater marginal (P = 0.04) and maximum (P = 0.02) irradiation doses. Seven patients underwent eight surgical resections of a progressing tumor during the mean period of 26.1 months after irradiation. Five patients (31 %) died because of tumor progression within the average time period of 16.8 months after GKS. Overall, at the time of the last follow-up just two patients (13 %) had no evidence of tumor regrowth, and only three patients (19 %) maintained good activities of daily living during 12, 59, and 69 months, respectively, after radiosurgery. Conclusion: GKS has limited efficacy in cases of non-benign meningioma. Better tumor control rates can be attained for small neoplasms treated with greater marginal and maximum irradiation doses.
    No preview · Article · Feb 2013 · Acta neurochirurgica. Supplement
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    ABSTRACT: Leksell GammaPlan (LGP) software was initially designed for Gamma Knife radiosurgery, but it can be suc-cessfully applied to planning of the open neurosurgical procedures as well. We present our initial experience of delineating the cranial nerves in the vicinity of skull base tumors, combined visualization of the implanted subdural electrodes and cortical anatomy to facilitate brain mapping, and fusion of structural magnetic resonance imaging and diffusion tensor imaging performed with the use of LGP before removal of intracranial neoplasms. Such preoperative information facilitated choosing the optimal approach and general surgical strategy, and corresponded well to the intraoperative findings. Therefore, LGP may be helpful for planning open neurosurgical procedures in cases of both extraaxial and intraaxial intracranial tumors.
    No preview · Article · Feb 2013 · Acta neurochirurgica. Supplement
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    T Takeuchi · M Sato · T Sonomura · T Itakura
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    ABSTRACT: Erdheim-Chester disease (ECD) is a rare non-Langerhans cell histiocytosis. We present a case of a 56-year-old male with ECD. As time progressed, involvement of the orbital fossa, cranial convexity, spinal cord, brain stem, thyroid, lung, retroperitoneum, lower extremity bones and skin were found. Previously reported cases reveal the frequency of ECD with spinal cord involvement is rare. Although this was a presumed diagnosis based on other lesions, our case is the first in which both intramedullary and epidural masses are present.
    Preview · Article · Mar 2012 · The British journal of radiology
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    ABSTRACT: To explore the optimal contrast material (CM) concentration for distinguishing CM, carotid stent (CS), and neck components in cone-beam computed tomography (CBCT) during carotid angiography (CBCT-CA). A neck phantom containing CS and contrast-filled imitation vessels of 9 mm diameter was scanned using CBCT. CM (300 mgI/ml) was used in concentrations of 100, 50, 33, 10, 5, and 1%. In a clinical study, 30 patients with a CS (Precise or Wallstent) underwent CBCT-CA with CM injected at a rate of 3 ml/s and a concentration of 10 or 20%. In the basic study, CBCTA using 5% CM enabled clear distinction among the three components under windowing at 1500 width and 300 center, and showed the exact diameter of the imitation vessel. Pixel values of CM inside the Precise and the Wallstent were 622.2 ± 32.9 (mean ± SD) and 746.0 ± 27.9, respectively. In the clinical study using CM at concentrations of 10 and 20%, pixel values of CM inside the Wallstent were 632.3 ± 69.2 and 1024.5 ± 99.0, respectively. Optimal CM concentration for distinguishing among the three components was 5% in the basic study; the optimal concentration was 10% in the clinical study.
    No preview · Article · Jan 2012 · Japanese journal of radiology

  • No preview · Chapter · Jan 2012

  • No preview · Article · Dec 2011 · Movement Disorders
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    ABSTRACT: Dystonia is a neurological disorder characterized by sustained or repetitive involuntary muscle contractions and abnormal postures. In the present article, we will introduce our recent electrophysiological studies in hyperkinetic transgenic mice generated as a model of DYT1 dystonia and in a human cervical dystonia patient, and discuss the pathophysiology of dystonia on the basis of these electrophysiological findings. Recording of neuronal activity in the awake state of DYT1 dystonia model mice revealed reduced spontaneous activity with bursts and pauses in both internal (GPi) and external (GPe) segments of the globus pallidus. Electrical stimulation of the primary motor cortex evoked responses composed of excitation and subsequent long-lasting inhibition, the latter of which was never observed in normal mice. In addition, somatotopic arrangements were disorganized in the GPi and GPe of dystonia model mice. In a human cervical dystonia patient, electrical stimulation of the primary motor cortex evoked similar long-lasting inhibition in the GPi and GPe. Thus, reduced GPi output may cause increased thalamic and cortical activity, resulting in the involuntary movements observed in dystonia.
    Full-text · Article · Nov 2011 · Frontiers in Systems Neuroscience
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    ABSTRACT: By causing damage to neural networks, spinal cord injuries (SCI) often result in severe motor and sensory dysfunction. Functional recovery requires axonal regrowth and regeneration of neural network, processes that are quite limited in the adult central nervous system (CNS). Previous work has shown that SCI lesions contain an accumulation of activated microglia, which can have multiple pathophysiological influences. Here, we show that activated microglia inhibit axonal growth via repulsive guidance molecule a (RGMa). We found that microglia activated by lipopolysaccharide (LPS) inhibited neurite outgrowth and induced growth cone collapse of cortical neurons in vitro--a pattern that was only observed when there was direct contact between microglia and neurons. After microglia were activated by LPS, they increased expression of RGMa; however, treatment with RGMa-neutralizing antibodies or transfection of RGMa siRNA attenuated the inhibitory effects of microglia on axonal outgrowth. Furthermore, minocycline, an inhibitor of microglial activation, attenuated the effects of microglia and RGMa expression. Finally, we examined whether these in vitro patterns could also be observed in vivo. Indeed, in a mouse SCI model, minocycline treatment reduced the accumulation of microglia and decreased RGMa expression after SCI, leading to reduced dieback in injured corticospinal tracts. These results suggest that activated microglia play a major role in inhibiting axon regeneration via RGMa in the injured CNS.
    Full-text · Article · Sep 2011 · PLoS ONE
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    Dataset: Table S2
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    ABSTRACT: Primers used in Real-time RT-PCR Analysis. (DOC)
    Preview · Dataset · Sep 2011
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    Dataset: Table S1
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    ABSTRACT: Antibodies used in Immunocytochemical and Immunohistochemical Analyses. (DOC)
    Preview · Dataset · Sep 2011
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    Dataset: Text S1
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    ABSTRACT: Supplementary Materials and Methods. (DOCX)
    Preview · Dataset · Sep 2011
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    ABSTRACT: Cilostazol(CLZ) has been used as a vasodilating anti-platelet drug clinically and demonstrated to inhibit proliferation of smooth muscle cells and effect on endothelial cells. However, the effect of CLZ on re-endothelialization including bone marrow (BM)-derived endothelial progenitor cell (EPC) contribution is unclear. We have investigated the hypothesis that CLZ might accelerate re-endothelialization with EPCs. Balloon carotid denudation was performed in male Sprague-Dawley rats. CLZ group was given CLZ mixed feed from 2 weeks before carotid injury. Control group was fed normal diet. CLZ accelerated re-endothelialization at 2 weeks after surgery and resulted in a significant reduction of neointima formation 4 weeks after surgery compared with that in control group. CLZ also increased the number of circulating EPCs throughout the time course. We examined the contribution of BM-derived EPCs to re-endothelialization by BM transplantation from Tie2/lacZ mice to nude rats. The number of Tie2-regulated X-gal positive cells on injured arterial luminal surface was increased at 2 weeks after surgery in CLZ group compared with that in control group. In vitro, CLZ enhanced proliferation, adhesion and migration activity, and differentiation with mRNA upregulation of adhesion molecule integrin αvβ3, chemokine receptor CXCR4 and growth factor VEGF assessed by real-time RT-PCR in rat BM-derived cultured EPCs. In addition, CLZ markedly increased the expression of SDF-1α that is a ligand of CXCR4 receptor in EPCs, in the media following vascular injury. CLZ promotes EPC mobilization from BM and EPC recruitment to sites of arterial injury, and thereby inhibited neointima formation with acceleration of re-endothelialization with EPCs as well as pre-existing endothelial cells in a rat carotid balloon injury model. CLZ could be not only an anti-platelet agent but also a promising tool for endothelial regeneration, which is a key event for preventing atherosclerosis or restenosis after vascular intervention.
    Full-text · Article · Sep 2011 · PLoS ONE

  • No preview · Article · Sep 2011 · Neuroscience Research
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    ABSTRACT: We analyzed the factors that affect the long-term clinical outcome of a series of patients with skull base meningiomas. Clinical records of 73 patients with cranial base meningiomas were reviewed retrospectively, of whom 13 patients experienced a recurrence at various times following the initial surgery. The mean follow-up time was 90.4 ± 21.2 months (range=60-124 months). Based on the location of the recurrence, patients with recurrence were divided into peripheral (n=6) and central (n=7) skull base groups. Of several variables analyzed using a multivariate logistic regression model, "high MIB-1 (Ki-67 proliferation antigen) labeling index" was an independent variable predicting poor long-term functional outcomes. Recurrence of the tumor at the central skull base was also a strong predictor of poor long-term outcomes. An increased proliferative potential, as indicated by a high MIB-1 labeling index, may induce repeated recurrences, eventually leading to worse functional outcomes, particularly for patients with central skull base meningiomas.
    No preview · Article · Jul 2011 · Journal of Clinical Neuroscience
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    ABSTRACT: Responses of neurons in the globus pallidus (GP) to cortical stimulation were recorded for the first time in humans. We performed microelectrode recordings of GP neurons in 10 Parkinson's disease (PD) patients and 1 cervical dystonia (CD) patient during surgeries to implant bilateral deep brain stimulation electrodes in the GP. To identify the motor territories in the external (GPe) and internal (GPi) segments of the GP, unitary responses evoked by stimulation of the primary motor cortex were observed by constructing peristimulus time histograms. Neurons in the motor territories of the GPe and GPi responded to cortical stimulation. Response patterns observed in the PD patients were combinations of an early excitation, an inhibition, and a late excitation. In addition, in the CD patient, a long-lasting inhibition was prominent, suggesting increased activity along the cortico-striato-GPe/GPi pathways. The firing rates of GPe and GPi neurons in the CD patient were lower than those in the PD patients. Many GPe and GPi neurons of the PD and CD patients showed burst or oscillatory burst activity. Effective cathodal contacts tended to be located close to the responding neurons. Such unitary responses induced by cortical stimulation may be of use to target motor territories of the GP for stereotactic functional neurosurgery. Future findings utilizing this method may give us new insights into understanding the pathophysiology of movement disorders.
    No preview · Article · Feb 2011 · Movement Disorders
  • Naoyuki Nakao · Toru Itakura
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    ABSTRACT: Pituitary adenomas with extensive suprasellar extension are a therapeutic challenge. The efficacy and safety of the endoscopic endonasal approach for non-functioning giant pituitary adenoma was evaluated retrospectively. A total of 43 consecutive patients with pituitary adenomas with a suprasellar extension of >20mm underwent tumor resection with a purely endoscopic endonasal approach, and their surgical outcomes were analyzed. At surgery, irrespective of the size and shape of the adenoma, every effort was made to perform intracapsular resection under direct visual control using an angled-lens endoscope. Gross total removal was achieved in 20 out of 43 patients. Postoperatively, 42 patients showed varying improvement of both visual field defects and impaired visual acuity. In two patients who presented with gait disturbance and cognitive dysfunction due to obstructive hydrocephalus, these symptoms were completely resolved. There were no serious operative complications. The results indicate that intracapsular resection via the endoscopic approach can be a safe and effective treatment for giant pituitary adenomas.
    No preview · Article · Jan 2011 · Journal of Clinical Neuroscience
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    Toshika Ohkawa · Naoyuki Nakao · Yuji Uematsu · Toru Itakura
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    ABSTRACT: A basal encephalocele often shows an insidious clinical course. Only two cases of temporal lobe encephalocele accompanied with tension pneumocephalus have previously been reported. In this paper, we describe a case of lateral sphenoid sinus encephalocele presenting with intraventricular tension pneumocephalus. A 54-year-old man was referred to our institution presenting with intraventricular tension pneumocephalus. He had undergone ventriculoperitoneal shunt placement for postmeningitis hydrocephalus 3 months before this admission. Precise imaging examinations detected evidence suggestive of a lateral sphenoidal sinus recess encephalocele. Endoscopic transnasal approach was performed for surgical repair of the encephalocele. The encephalocele was removed with subsequent repair of the bony defect. Histological examination showed that the encephalocele includes a part of the ventricular system. This indicates that air might enter directly into the ventricular system after rupture of the temporal lobe encephalocele. A lateral sphenoid sinus encephalocele would potentially cause intraventricular tension pneumocephalus, although pneumocephalus is an extremely unusual complication of this type of basal encephaloceles.
    Preview · Article · Nov 2010 · Skull Base
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    ABSTRACT: Intra-axial pseudotumors in the central nervous system often mimic malignant brain tumors and cause difficulty in diagnosis and treatment. The present study investigates their radiologic and histological features to elucidate diagnostic clues. Six cases were included in the study, one man and five women, ranging in age from 44 to 87 years (mean age, 61 years). Histologically, three cases had demyelination, and one case each had abscess, angiitis, and non-Langerhans cell histiocytosis. All cases were evaluated radiologically on MRI, most of them by thallim-201 single photon emission tomography ((201)Tl-SPECT). These cases were examined using H&E, special stains, and immunohistochemical studies with a variety of antibodies. MRI demonstrated perifocal edema and ring-like or solid enhancement, mimicking the malignant tumors. Diffusion-weighted MRI showed a hypo-iso-intensity with a hyperintensity on the apparent diffusion coefficient. A (201)Tl-SPECT study revealed no uptake. Although there were various kinds of pathology, inflammatory cells were observed, associated with vascular proliferation and reactive astrocytosis. In addition, some cases showed demyelinating or destructive changes. These results suggested that intra-axial pseudotumors in the central nervous system contain various kinds of pathology, and detailed clinicopathological analysis is important from the point of view of differential diagnosis.
    No preview · Article · Oct 2010 · Brain Tumor Pathology
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    ABSTRACT: We report a 23-year-old man with left dominant parietal cortical dysplasia manifesting as ictal asomatognosia. The man had experienced seizures, during which he underwent ictal asomatognosia as a feeling of loss of his right extremities. Scalp electroencephalography (EEG) showed interictal discharges in the left parietal region of his brain. Magnetic resonance fluid-attenuated inversion recovery (FLAIR) imaging revealed a hyperintense lesion in the left superior parietal lobule. A [(123)I]-iomazenil (IMZ) single-photon-emission CT scan demonstrated an area of low IMZ binding coincident with the lesion observed in the MRI scan. Invasive EEG monitoring showed ictal discharges in the cortex posterior to the postcentral sulcus. High-frequency electrical stimulation of the same area of the cortex also induced asomatognosia of the patient's right forearm. We performed a corticectomy of the anterior part of the superior parietal lobule, which resulted in no new neurological deficits. The seizures disappeared after surgery with the maintenance of preoperative medication. Therefore, the anterior part of the superior parietal lobule may be a symptomatogenic zone for ictal asomatognosia.
    No preview · Article · Sep 2010 · Journal of Clinical Neuroscience

Publication Stats

4k Citations
556.64 Total Impact Points

Institutions

  • 2013
    • Tokyo Women's Medical University
      • Institute of Advanced Biomedical Engineering and Science
      Edo, Tokyo, Japan
  • 1981-2013
    • Wakayama Medical University
      • • Department of Radiology
      • • Department of Medicine
      Wakayama, Wakayama, Japan
    • California Institute of Technology
      • Division of Biology
      Pasadena, California, United States
  • 2006
    • Kawasaki Medical University
      Kurasiki, Okayama, Japan
  • 2000
    • Japan Red Cross Fukuoka Hospital
      Hukuoka, Fukuoka, Japan
  • 1988-1999
    • Hidaka Hospital
      Takasaki, Gunma, Japan
  • 1997
    • University of Sydney
      Sydney, New South Wales, Australia
  • 1994
    • University of Illinois Springfield
      Спрингфилд, Florida, United States