Publications by authors named "Ryota Mashiko"

Most asymptomatic patients with chronic subdural hematoma (CSDH) are followed conservatively but can require surgical treatment if the hematoma expands. We conducted a retrospective evaluation of the effect of Gorei-san on CSDH. This study included patients treated between April 2013 and March 2015.

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Background: Brainstem anesthesia is a transient loss of brainstem function usually associated with retrobulbar block and rarely seen by neurosurgeons.

Case Description: Here, we report a case of brainstem anesthesia during shunt revision operation in a 79-year-old woman. Local anesthesia administered at the end of surgery was thought to have infiltrated the subarachnoid space through a burr hole, causing prolonged unconsciousness and cranial nerves' impairment.

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A 24-year-old woman was admitted to our hospital after convulsive status epilepticus. A cerebral magnetic resonance venography revealed a persistent fetal falcine sinus. Additionally, the posterior third of the superior sagittal sinus was hypoplastic and the abnormal deep venous drainage was accompanied.

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Article Synopsis
  • Meningeal carcinomatosis is a rare metastatic condition seen in cancer patients, diagnosed through typical imaging and signs of a primary tumor.
  • A case study of a 72-year-old man illustrates challenges in diagnosis, leading to initial misinterpretation as idiopathic hydrocephalus.
  • Despite treatment efforts, including a shunt operation and corticosteroids, the patient's neurological symptoms worsened, revealing meningeal carcinomatosis related to lung adenocarcinoma at autopsy.
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Because of relative simplicity of signal transduction pathway, bacterial chemotaxis sensory systems have been expected to be applied to biosensor. Tar and Tsr receptors mediate chemotaxis of and have been studied extensively as models of chemoreception by bacterial two-transmembrane receptors. Such studies are typically conducted using two canonical ligands: l-aspartate for Tar and l-serine for Tsr.

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Minor damage to the scalp may lead to intracranial infection. Moreover, the postoperative state of the scalp, skull and meninges is especially noteworthy with respect to invasion of pathogens into the skull. Therefore, a detailed medical history should be obtained from patients with even minor scalp injuries to avoid intracranial infection.

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If we use the same naming policy of middle cerebral arterial anomalies, then accessory anterior cerebral arteries (ACAs) should be applied for ACA anomalies originating from the ACA. We experienced such a rare ACA anomaly, which we referred to as true accessory ACA.

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Intracranial lipoma concomitant with traumatic pneumocephalus is very rare and, to the best of our knowledge, there has been no report describing this condition. It may be difficult to distinguish lipoma from intracranial air only with CT, but it is necessary to avoid overtreatment. We report a case of quadrigeminal cistern lipoma mimicking intracranial air in a patient with traumatic pneumocephalus.

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Although antiangiogenic treatment for malignant glioma using bevacizumab in combination with irinotecan chemotherapy has a promising effect on survival, the high incidence of increasing infiltrative tumors can be a problem in resistance to antiangiogenic therapy. In this study, we detected failure of bevacizumab treatment for malignant glioma through upregulation of metalloproteinase activity in the urine, as well as infiltrative tumors on MRI. In addition, MMP9 has been proved as a molecule that facilitates its infiltrative behavior in vivo in the brain animal model.

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Hypoxia-inducible factor (HIF)-1α and HIF-2α expression were investigated immunohistochemically as determinants of prognosis in 42 cases of astrocytic tumors associated with necrosis grade on magnetic resonance (MR) imaging. Expression of HIF-1α was determined immunohistologically. The degree of necrosis on MR images was divided into four grades.

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Irinotecan (CPT-11) has shown emerging promise in the treatment of malignant gliomas. It is believed the mechanism of action of irinotecan is to sensitize glioma cells to the cytotoxic action of radiation therapy and alkylating agents. However, clinical trials using weekly or three-weekly doses of CPT-11 have demonstrated imaging responses in only 10-15% of patients.

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A 74-year-old man presented with life-threatening intracranial hemorrhage and prolonged activated partial thromboplastin time (APTT). The massive subdural hematoma was removed, but multiple intracranial hemorrhages occurred despite the administration of factor VIII and factor IX concentrates. Subdural hematoma, intracerebral hemorrhage in the left temporal lobe, and thalamic hemorrhage subsequently occurred with further prolongation of APTT.

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An 18-year-old man presented with a rare spinal subdural hematoma (SSH) manifesting as headache, which developed following diving into the sea the day before. Computed tomography of the head revealed no abnormality. His headache persisted followed by neck stiffness and mild lumbago.

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A 27-year-old woman was referred to our hospital with mild disorientation, bilateral abducens nerve palsy, and mild left hemiparesis. Magnetic resonance (MR) imaging revealed diffuse mass lesions resembling malignant glioma in the right frontal intraparenchymal region, with enhancement of multiple meningeal and intraparenchymal nodules. Partial resection of the frontal lesion was performed.

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Objective: Symptomatic unruptured aneurysms have been considered at relatively high risk for future rupture, and the majority of aneurysms that cause symptoms of mass effect are large. Unruptured aneurysms smaller than 1 cm in diameter sometimes cause neurological symptoms, but their clinical aspects remain obscure. In this article, we review our experience with small unruptured aneurysms presenting with oculomotor nerve palsy.

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Synopsis of recent research by authors named "Ryota Mashiko"

  • Ryota Mashiko's recent research primarily focuses on various aspects of neurosurgery and neurological conditions, addressing both surgical interventions and case studies related to chronic subdural hematoma, brainstem anesthesia, and dural sinus thrombosis.
  • His work includes investigating conservative treatment options for chronic subdural hematoma using Gorei-san, highlighting outcomes from a retrospective evaluation of asymptomatic patients.
  • Additionally, Mashiko has explored unique neurological presentations in cases of meningeal carcinomatosis and intracranial infections, contributing to a deeper understanding of atypical imaging findings and postoperative risks in neurosurgical patients.