Biomedical subjects

Soichi Oya

Publications and source records attributed to Soichi Oya.

8 recordsLinked to original sources

PubMed2026

Evaluation of the clinical and mechanistic role of MCM2 expression in the prediction of meningioma recurrence after radiotherapy.

OBJECTIVE: Postoperative radiotherapy is an effective treatment for meningiomas; however, treatment response varies among patients. In addition, practical methods for predicting tumor recurrence after radiotherapy have not been well established. Minichromosome maintenance protein 2 (MCM2), a key regulator of DNA replication licensing, was recently implicated in highly proliferative molecular subtypes of meningioma. In this study, the authors evaluated whether MCM2 immunohistochemical expression predicts response to radiotherapy in patients with meningiomas. METHODS: The authors retrospectively analyzed the records of patients with WHO grade 1-3 meningiomas treated with resection followed by radiotherapy at a single institution between July 2003 and November 2023. The MCM2 labeling index was assessed immunohistochemically, and patients were stratified into MCM2-high and -low groups using a cutoff of 35%. Progression-free survival (PFS) was defined as the interval from the completion of radiation therapy to postoperative radiological tumor recurrence or regrowth. Patients who showed no progression were censored at their last follow-up. PFS was estimated using Kaplan-Meier analysis and subsequently evaluated with Cox proportional hazards models. To further investigate the biological mechanisms associated with MCM2 expression, comprehensive transcriptomic analyses, including gene set enrichment analysis, was performed to elucidate the molecular processes that occur within MCM2-high tumors. RESULTS: The study population included 15 men (42%) and 21 women (58%), with a mean age of 63 years. Ten tumors (28%) were classified as MCM2-high meningiomas and 26 (72%) as MCM2-low meningiomas. High MCM2 expression was significantly associated with WHO grades 2-3 histology and higher Ki-67 labeling indices. During a median follow-up of 2.52 years, tumor progression after radiotherapy occurred in 47% of the patients. High MCM2 expression (HR 8.34, p = 0.03) was significantly associated with shorter PFS and remained an independent predictor of recurrence after adjustment for WHO grade, tumor size, and Ki-67 labeling index. Transcriptomic analyses of MCM2-high tumors revealed upregulation of cell proliferation-related pathways, accompanied by increased signaling through the E2F8-CHEK1 axis associated with radiation resistance and suppression of the TNF-α signaling pathway implicated in radiosensitivity. CONCLUSIONS: In meningiomas, high MCM2 expression is associated with early recurrence following radiotherapy. The study findings suggest that this association is driven by diverse biological mechanisms related to cell cycle regulation and radioresistance. Immunohistochemical assessment of MCM2 expression may serve as a practical and accessible biomarker for risk stratification and may support the future development of individualized postoperative radiotherapy strategies.

Humans↗

PubMed2005

Ruptured arteriovenous malformation in the auditory nerve: technical case report.

OBJECTIVE AND IMPORTANCE: Arteriovenous malformations in the cranial nerves are very rare, and only one case has been reported in the literature. To our knowledge, this is the first case report of an arteriovenous malformation in the auditory nerve. CLINICAL PRESENTATION: A 30-year-old woman presented with a subarachnoid hemorrhage resulting from rupture of an arteriovenous malformation in the auditory nerve. INTERVENTION: During the operation, the auditory nerve bundle was found to be severely damaged and a nidus was identified inside the bundle. CONCLUSION: Although arteriovenous malformations are thought to arise in the 4th to 8th weeks of gestation, this case might indicate a more specific time of emergence based on embryogenesis of the cranial nerves.

Adult↗

PubMed2005

Intracranial extracerebral glioneuronal heterotopia. Case report and review of the literature.

The authors report a case of intracranial extracerebral glioneuronal heterotopia (IEGH) in an infant. Glioneuronal heterotopias are rare congenital disorders that arise in the head, face, spine, and thoracic cavity. They consist of nodular accumulations of neuronal and glial cells that have developed abnormally, ranging in size from small lesions to large masses. Among heterotopias, IEGHs are relatively rare. They cause various clinical symptoms, depending on their size and location. The neuroimaging studies, histological examinations, and intraoperative findings presented provide insight into the pathogenesis of this disorder. The findings support the separation and detachment theory, which proposes that IEGHs originate from a third telencephalon that erroneously forms between the 4th and 6th week of embryogenesis. More detailed case reports are necessary to understand fully the pathogenesis of IEGHs.

Adult↗

PubMed2004

[A case of pial single-channel cerebral arteriovenous fistula].

A 60-year-old man presented with dizziness, dysarthria, and right hemifacial palsy with sudden onset. Computed tomography scan revealed a small cerebellar hematoma near the left flocculus. Since the site of the hemorrhage was atypical for cerebellar hemorrhages, emergency angiography was performed and revealed a pial single-channel arteriovenous fistula (AVF) in the early arterial phase with drainage into the dilated perimedullary vein. The feeding artery was a peripheral branch of the left anterior inferior cerebellar artery. There were no angiographical findings indicating a nidus or capillary network. The patient underwent left lateral suboccipital craniotomy. A small dilated perimedullary vein and an abnormally red spherical varix were found during the operation. A peripheral branch of the left anterior inferior cerebellar artery was thought to be a feeder because it seemed to be firmly attached to the dilated vein. Based on the operative technique for dural AVFs, electrocoagulation of the varix was performed aiming at obliteration of the fistula. The postoperative angiogram demonstrated the obliteration of the fistula and of the early filling vein. Feeders of cerebral AVF are cerebral arteries. A pial single-channel AVF is defined as a vascular malformation with a single venous channel in communication with one or more arteries with no intervening nidus or vessels. To date, reports in the literature of cerebral arteriovenous fistula have been very few. Its clinical entities such as origin, bleeding rate and the necessity of surgery remain subjects of debate. Here we report our experience and discuss its issues of the treatment we used.

Arteriovenous Fistula↗

PubMed2003

Adult-onset moyamoya disease with repetitive ischemic attacks successfully treated by superficial temporal-middle cerebral artery bypass--case report.

A 78-year-old Japanese woman presented with adult-onset moyamoya disease manifesting as repetitive ischemic attacks over a period of 26 years. Initial ischemic attack occurred at age 52 years. Neurological status deteriorated, associated with worsening in angiographical and single photon emission computed tomography findings over the last 10 years. She suffered frequent transient attacks of aphasia and right hemiparesis. Superficial temporal-middle cerebral artery anastomosis was performed. Postoperative angiography and single photon emission computed tomography revealed a marked increase in cerebral blood flow and symptoms showed considerable improvement. Direct revascularization may be the treatment of choice even for aged patients with moyamoya disease.

Aged↗

PubMed2002

Tilting operating table with self-control foot switch: a new neurosurgical tool.

BACKGROUND: Observation of the surgical field from all directions is essential in microneurosurgery. A tilting operating table operated by the surgeon can satisfy this need. METHODS: A tilting operating table operated by the surgeon using a foot switch was developed by modifying the Sugita table incorporating the X-Y shifter. RESULTS AND CONCLUSIONS: The modified operating table allows the surgeon to move the patient in the head up or down directions, as well as the left side down or right side down directions, so the surgical field can be inspected from all aspects without changing the vertical axis of the operating microscope.

Equipment Design↗

PubMed2002

Snare technique of vascular transposition for microvascular decompression--technical note.

Recurrence of trigeminal neuralgia (TN) or hemifacial spasm (HFS) after microvascular decompression (MVD) is not rare. The prosthesis material eventually adheres to the neurovascular structures and again transmits arterial pulsation to the nerve. A snare ligature technique using a Gore-Tex tape can be used for the transposition of the offending artery. No prosthesis is necessary once the transposition is complete. This technique requires introduction of either Gore-Tex tape or thread around the artery and suture over the petrous dura, so an adequate working space as if operating in a shallow basin is essential. Therefore, the osteoplastic craniotomy is a little larger than usual with the scalp flap entirely reflected using a semicircular skin incision. The Gore-Tex tape can be directly snared around the artery and sutured over the petrous dura. If this procedure is difficult, a thread can be attached to both ends of the Gore-Tex tape to pass the tape around the vessel. Seven patients with TN and 13 patients with HFS have undergone this surgery. Although the follow-up period is not yet long enough, there has been no case of recurrence. The present technique for MVD can provide complete and permanent transposition of the offending artery.

Decompression, Surgical↗

PubMedDate not supplied

Posterolateral odontoidectomy for irreducible atlantoaxial dislocation: a technical case report.

BACKGROUND CONTEXT: For the treatment of irreducible atlantoaxial dislocation (AAD), anterior decompression has been commonly used by removal of the odontoid process and fixation of the vertebral body by means of the transoral approach. Although the transoral approach has been well established, there are some disadvantages. By contrast, there have been few technical case reports of the posterolateral approach, especially for irreducible AAD. PURPOSE: To describe a technical case report of the posterolateral approach for irreducible AAD, demonstrating the specific advantages. STUDY DESIGN/SETTING: Technical case report. PATIENT SAMPLE: Case report. OUTCOME MEASURES: Report of postoperative symptoms. METHODS/DESCRIPTION: A 74-year-old woman presented with sudden left hemiparesis because of irreducible AAD. She underwent the odontoidectomy and reduction by means of the posterolateral approach. Posterior fixation with instrumentation and an iliac bone graft was performed 16 days later. The results of radiological examinations were satisfactory. The posterolateral approach takes advantage of the particular features of C1-C2 dislocation of irreducible AAD. CONCLUSIONS: We suggest the possibility that the posterolateral approach is feasible and effective in most cases with irreducible AAD.

Aged↗