Publications by authors named "Ryuichi Hirayama"

Background: Glioblastoma is characterized by neovascularization and diffuse infiltration into the adjacent tissue. T2*-based dynamic susceptibility contrast (DSC) MR perfusion images provide useful measurements of the biomarkers associated with tumor perfusion. This study aimed to distinguish infiltrating tumors from vasogenic edema in glioblastomas using DSC-MR perfusion images.

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Background: N-butyl cyanoacrylate (n-BCA) is often used for preoperative transarterial embolization (TAE) of meningiomas. However, factors affecting the embolization effect with n-BCA remain unclear. This study aimed to clarify the factors associated with the embolization rate after TAE using n-BCA in meningioma, from the aspect of feeder architecture.

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O6-methylguanine DNA methyltransferase promoter methylation is an important clinical biomarker of newly diagnosed glioblastoma. Previous radiological studies using dynamic susceptibility contrast (DSC) magnetic resonance imaging (MRI) perfusion have aimed to predict methylation status non-invasively in gliomas with radiological characteristics. The possibility of predicting methylation status using DSC-MRI perfusion with a radiological approach remains controversial.

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Article Synopsis
  • Glioblastoma multiforme (GBM) is a highly aggressive brain tumor that urgently needs new therapies; CAR T cell therapy has shown promise but is costly and time-intensive.
  • Researchers are exploring CAR-transduced natural killer (NK) cells as an "off-the-shelf" immunotherapy alternative, which can avoid complications like graft-versus-host disease.
  • Both CAR-T and CAR-NK cells targeting the B7-H3 protein demonstrated significant effectiveness in killing GBM cells in lab tests and in animal models, suggesting they could be viable treatment options for this aggressive cancer.
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  • The study investigates genetic factors related to meningiomas, a common type of brain tumor, specifically in a Japanese population, as previous research mainly focused on Europeans.
  • Researchers analyzed 401 meningioma patients and over 50,000 control participants, ultimately identifying over 8 million genetic variants but failing to find any significant variants associated with meningioma susceptibility.
  • This first genome-wide association study on meningiomas in East Asians aims to enrich future genetic research in this area, despite not yielding significant results.
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Background: Although awake surgery is the gold standard for resecting brain tumors in eloquent regions, patients with hearing impairment require special consideration during intraoperative tasks.

Case Description: We present a case of awake surgery using sign language in a 45-year-old right-handed native male patient with hearing impairment and a neoplastic lesion in the left frontal lobe, pars triangularis (suspected to be a low-grade glioma). The patient primarily communicated through sign language and writing but was able to speak at a sufficiently audible level through childhood training.

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Background: Meningiomas are among the most common intracranial tumors. In these tumors, volumetric assessment is not only important for planning therapeutic intervention but also for follow-up examination.However, a highly accurate automated volumetric method for meningiomas using single-modality magnetic resonance imaging (MRI) has not yet been reported.

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The blood-brain barrier (BBB) plays pivotal roles in synaptic and neuronal functioning by sealing the space between adjacent microvascular endothelial cells. BBB breakdown is present in patients with mild cognitive impairment (MCI) or Alzheimer disease (AD). Claudin-5 (CLDN-5) is a tetra-spanning protein essential for sealing the intercellular space between adjacent endothelial cells in the BBB.

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  • The study focuses on the challenges of removing basal ganglia tumors due to the deep location of perforating arteries and the discomfort faced by surgeons using traditional microscopes.
  • Using a 4K-HD 3D exoscope system improved the surgical approach, allowing for better visualization and positioning, making it easier to access difficult-to-reach arteries during tumor resection.
  • Although one case experienced some postoperative complications like infarction, the overall results showed successful tumor removal with minimal neurological issues for the patients involved.
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Background: New therapies for glioblastoma (GBM) are urgently needed because the disease prognosis is poor. Chimeric antigen receptor (CAR)-T cell therapy that targets GBM-specific cell surface antigens is a promising therapeutic strategy. However, extensive transcriptome analyses have uncovered few GBM-specific target antigens.

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  • Meningiomas, the most common primary intracranial tumors, have varying growth rates based on their location, with convexity, parasagittal, and falx meningiomas comprising about 50%-65% of cases.
  • A study analyzing 313 cases found a median relative growth rate (RGR) of 6.1% and an annual volume change (AVC) of 0.20 cm³/year, with significant variations based on factors like sex, age, tumor location, and MRI characteristics.
  • The study identified three growth categories, revealing that extremely high-growth meningiomas could increase in volume by 5.24 cm³ over five years, while low-growth tumors showed minimal change,
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Background: Neuroendocrine tumors (NETs) are uncommon neoplasms arising from neuroendocrine cells and are rarely associated with intracranial metastases.

Case Description: We discuss the case of a 74-year-old woman with a right CPA tumor. She had a history of retroperitoneal NET, but was diagnosed with vestibular schwannoma due to a right-sided hearing loss and a right CPA tumor along the VII and VIII nerves.

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The blood-brain barrier is a major obstacle to the delivery of drugs to the central nervous system. In the blood-brain barrier, the spaces between adjacent brain microvascular endothelial cells are sealed by multiprotein complexes known as tight junctions. Among the many components of the tight junction, claudin-5 has received the most attention as a target for loosening the tight-junction seal and allowing drugs to be delivered to the brain.

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Meningiomas are the most common primary intracranial neoplasms and clinical symptom appearance depends on their volume and location. This study aimed to identify factors that influence clinical symptoms and to determine a specific threshold tumor volume for the prediction of symptomatic progression in patients with convexity, parasagittal, and falx meningiomas. We retrospectively studied patients with radiologically suspected convexity, parasagittal, or falx meningiomas at our institution.

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Background: Wilms' tumor gene 1 (WT1) peptide vaccine and anti-programmed cell death-1 (anti-PD-1) antibody are expected as immunotherapies to improve the clinical outcome of glioblastoma. The aims of this study were to clarify how each immunotherapy affects tumor-infiltrating immune cells (TIIs) and to determine whether the combination of these two therapies could synergistically work.

Methods: Mice were transplanted with WT1 and programmed cell death-ligand 1 doubly expressing glioblastoma cells into brain followed by treatment with WT1 peptide vaccine, anti-PD-1 antibody, or the combination of the two, and survival of each therapy was compared.

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Claudin-5 (CLDN-5) is an essential component of the tight junction seal in the blood-brain barrier. Previously, we showed that CLDN-5 modulation in vitro via an anti-CLDN-5 monoclonal antibody (mAb) may be useful for increasing the permeability of the blood-brain barrier for drug delivery to the brain. Based on these findings, here we examined the safety and efficacy of the anti-CLDN-5 mAb in a non-human primate.

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We conducted a prospective multicenter trial to compare the usefulness of C-methionine (MET) and F-fluorodeoxyglucose (FDG) positron emission tomography (PET) for identifying tumor recurrence. Patients with clinically suspected tumor recurrence after radiotherapy underwent both C-MET and F-FDG PET. When a lesion showed a visually detected uptake of either tracer, it was surgically resected for histopathological analysis.

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Objective: Meningiomas are the most frequent primary brain tumors. The long-term natural history of asymptomatic meningiomas remains unclear and difficult to predict accurately, however. The purpose of this study was to determine the subsequent course of asymptomatic meningiomas preceded by 5 years of no treatment.

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Background: Intraorbital aneurysms are rare, and most of them originate from the ophthalmic arteries. Herein, we report a case of meningolacrimal artery aneurysm associated with a meningioma.

Case Description: A 55-year-old woman had a frontal convexity meningioma identified by brain magnetic resonance imaging during a checkup.

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Background: Conjoined twins represent a rare congenital malformation. Pygopagus twins are fused at the sacrum and perineum, with union of the spine. The authors report a successful separation of a unique case of pygopagus twins sharing a U-shaped spinal cord, which the authors identified through aberrant nerves by intraoperative physiological spinal root examination.

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The current research tested the hypothesis that inversion time (TI) shorter than 2,400 ms under 3T for FLAIR can improve the diagnostic accuracy of the T2-FLAIR mismatch sign for identifying mt, non-CODEL astrocytomas. We prepared three different cohorts; 94 MRI from 76 mt, non-CODEL Lower-grade gliomas (LrGGs), 33 MRI from 31 LrGG under the restriction of FLAIR being acquired with TI < 2,400 ms for 3T or 2,016 ms for 1.5T, and 112 MRI from 112 patients from the TCIA/TCGA dataset for LrGG.

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For drugs that are intended to fill unmet medical needs, such as the treatment of rare diseases or a subtype of cancer, it can take a long time to conduct confirmatory clinical trials due to limited patient availability. Delayed access to these drugs increases the risk of mortality of patients with these diseases. To address this issue, the Ministry of Health, Labour, and Welfare of Japan has decided to implement the Conditional Early Approval System with issuing the Ministry Notification in 2017.

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The Japanese conditional and time-limited (CTL) approval framework, a tiered system for regenerative medical products, was initiated in 2014. Here, we compare the dossiers of six regenerative medical products with either direct full approval or CTL approval, and we discuss the regulatory considerations for obtaining approval under the CTL approval framework.

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Aim: To evaluate the toxicity and efficacy of re-irradiation with salvage stereotactic radiotherapy (SRT) for recurrent glioma using CyberKnife.

Patients And Methods: This study retrospectively investigated 35 patients with 48 recurrent grade 2-4 gliomas who received SRT between 1998 and 2011. Six patients (17.

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OBJECTIVE In the present study the authors aimed to determine preferred locations of meningiomas by avoiding descriptive analysis and instead using voxel-based lesion mapping and 3D image-rendering techniques. METHODS Magnetic resonance images obtained in 248 treatment-naïve meningioma patients with 260 lesions were retrospectively and consecutively collected. All images were registered to a 1-mm isotropic, high-resolution, T1-weighted brain atlas provided by the Montreal Neurological Institute (the MNI152), and a lesion frequency map was created, followed by 3D volume rendering to visualize the preferred locations of meningiomas in 3D.

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