Yoji Tamura

Boron neutron capture therapy for malignant tumors related to meningiomas.

OBJECTIVE Malignant meningiomas, similar to glioblastomas, are difficult tumors to control. We tried to control malignant tumors related to meningiomas by boron neutron capture therapy (BNCT). METHODS Since June 2005, we applied BNCT with 13 rounds of neutron irradiation to seven cases of malignant tumors related to meningiomas. Three were anaplastic meningiomas, two were papillary meningiomas, one was an atypical meningioma, and one was a sarcoma transformed from a meningioma with cervical lymph node metastasis. All patients had previously undergone repetitive surgeries and radiotherapy. Follow-up images were available for six patients with an observation period between 7 and 13 months. We applied 18F-boronophenylalanine (BPA)-positron emission tomography (PET) before BNCT in six of the seven patients. One patient underwent methionine-PET instead of 18F-BPA-PET. RESULTS Five of the six patients who underwent BPA-PET analysis showed good BPA uptake, with a greater than 2.7 tumor-to-healthy brain ratio. The atypical meningioma case showed a tumor-to-healthy brain ratio of 2.0. The original tumor sizes were between 13.6 and 109 ml. Two of the three anaplastic meningiomas showed a complete response, and all six patients available for follow-up imaging showed radiographic improvements. Clinical symptoms before BNCT, such as hemiparesis and facial pain, were improved after BNCT in all but one patient. In this patient, a huge atypical meningioma arose from the falcotentorial junction and extended to the bilateral occipital lobes and brainstem; visual problems worsened after repetitive BNCT, with an increase in peritumoral edema. CONCLUSION Malignant meningiomas seem to be good candidates for BNCT.

Eosinophilic myelitis associated with atopic diathesis: a combined neuroimaging and histopathological study

Abstract. Histologically proven eosinophilic myelitis has rarely been reported except in connection with parasitism. To clarify its clinicopathological features, we conducted a nationwide survey of biopsy-proven eosinophilic myelitis of unknown cause throughout Japan. Six such cases were collected and studied immunologically and pathologically. All were young to middle-aged men. All showed a protracted and fluctuating course with mild disability for 3–25 (mean 12.5) months before biopsy. Magnetic resonance imaging revealed localized lesions of T2-high and T1-iso signal intensity with a partial gadolinium enhancement in all cases. Cerebrospinal fluid (CSF) examinations were completely normal except for modest pleocytosis in two cases. Eosinophilia was present in the peripheral blood in two cases but was absent from the CSF of all cases. In spite of the chronic nature of the disease, spinal cord pathology revealed very active lesions with marked cell infiltration consisting mainly of CD8+ T cells and varying numbers of eosinophils in the perivascular areas and the parenchyma. Both the myelin and axons were severely disrupted in all cases. Moreover, eosinophil cationic protein (ECP), an activated eosinophil product, was heavily deposited in the tissues. All but one case had hyperIgEemia and mite antigen-specific IgE in the sera, and two had accompanying atopic disorders. The present study thus revealed idiopathic eosinophilic myelitis to be a localized and persistent inflammation of the spinal cord, with distinct clinicopathological features, that has a possible link to atopic diathesis.

The use of intraoperative near-infrared indocyanine green videoangiography in the microscopic resection of hemangioblastomas

BackgroundThe authors assessed the usefulness of intraoperative near-infrared indocyanine green videoangiography (ICG-VA) in the microscopic resection of hemangioblastomas.MethodsFrom January 2009 to February 2012, nine consecutive patients (seven men, two women) who underwent surgery for hemangioblastomas using intraoperative ICG-VA were included in this study. Surgery was performed on four cystic cerebellar lesions with mural nodules, two solid tumors (one in the cerebellar hemisphere and one in the medulla oblongata), one spinal tumor and multiple tumors in two patients with von Hippel-Lindau disease. Of the nine patients, three were treated for recurrent tumor. The ICG-induced fluorescence images of hemangioblastomas with variable presentation were evaluated.ResultsAll tumors could be completely removed en bloc. Blood flow in the tumor and tumor-related vessels at the brain surface were clearly detected by ICG-VA in all cases, except one recurrent tumor where postoperative adhesive scar tissue obstructed ICG-induced fluorescence resulting in poor delineation of the blood flow patterns and tumor margins. ICG-VA was also helpful for detecting the multiple small mural nodules within the cyst or the tumors buried under thin gliotic neural tissue despite reduced fluorescence.ConclusionIntraoperative ICG-VA is a safe and easy modality for confirming the vascular flow patterns in hemangioblastomas. In addition, ICG-VA provided useful information for intracystic small lesions or lesions concealed under thin brain tissue in order to accomplish total resection of these tumors.

Thymic carcinoma presenting as cranial metastasis with intradural and extracranial extension: case report.

OBJECTIVE AND IMPORTANCEThymic carcinoma is an uncommon malignant tumor that is different from thymoma. Cranial and brain metastases from this tumor are extremely rare. We report a thymic carcinoma with cranial metastasis and discuss the behavior of this tumor. CLINICAL PRESENTATIONA 50-year-old man presented with headache and a palpable scalp tumor. Computed tomographic scans and magnetic resonance images revealed an osteolytic tumor with intradural and extracranial extension in the right occipital bone. INTERVENTIONAfter gross total resection and histological diagnosis, further investigation revealed a primary thymic tumor in the anterior upper mediastinum and liver metastases. The patient received multiple-cycle chemotherapy (cisplatin and gemcitabine) for primary and metastatic lesions. CONCLUSIONThymic carcinoma has a poor prognosis because of a high degree of malignancy, early metastasis, and delayed diagnosis. Thus, treatment of a patient with this tumor calls for prompt diagnosis, surgical treatment, and optimal adjuvant therapy.

Effect of Ebselen on Contractile Responses in Perfused Rabbit Basilar Artery

OBJECTIVE To evaluate the possible role of the antioxidant ebselen in the treatment of cerebral vasospasm, we examined the effects of ebselen on the vasoactive mechanisms induced by endothelin (ET)-1, oxyhemoglobin, and oxygen-derived radicals. METHODS Isolated rabbit basilar arteries with intact endothelium were fixed in a perfusion system and perfused intraluminally. Contraction of the artery was detected as an increase in perfusion pressure. RESULTS Ebselen, in a certain concentration range (3 x 10(-6) and 10(-5) mol/L), significantly reduced the contractile response to ET-1 (10(-10) to 10(-8) mol/L) but not the contraction induced by 40 mmol/L potassium. It reduced the contraction induced by 10(-4) mol/L 1,2-dioctanoyl-sn-glycerol, a protein kinase C activator. Addition of 10(-5) mol/L dithiothreitol, a sulfhydryl-reducing agent, partially reversed the inhibitory effects of ebselen on ET-1- and 1,2-dioctanoyl-sn-glycerol-induced contractions. Ebselen (10(-5) mol/L) as well as a combination of catalase (1000 units/mL) and superoxide dismutase (150 units/mL) inhibited the potentiating effects of oxyhemoglobin (10(-5) mol/L) on ET-1-induced contraction. Both ebselen and catalase inhibited the contractile response to hydroxyl radical generated by ferrous ion (10(-3) mol/L) plus hydrogen peroxide (10(-2) mol/L). Ebselen reduced the response to potassium when a high dose (3 x 10(-5) mol/L) was applied and failed to preserve contractility of the preparation after exposure to hydroxyl radical. CONCLUSION Ebselen suppressed ET-1-induced contraction and synergetic interaction between oxyhemoglobin and ET-1, where free radical formation was involved. These effects may result from modification of the intracellular regulatory system including protein kinase C, as well as from protection against free radicals.

Dissection of both frontal and parietal branches of the superficial temporal artery for bypass surgery through a single linear skin incision

BackgroundDouble superficial temporal artery (STA) to middle cerebral artery (MCA) bypass surgery has typically involved more than one linear incision. In this report, we demonstrate how the procedure can be performed through a single linear skin incision over the parietal branch of the STA.MethodsInitial dissection of the parietal branch and creation of a subcutaneous cavity along the frontal branch were performed using the conventional microscopic method. Detailed additional dissection and isolation of the frontal branch were accomplished with the aid of an endoscopic retractor.ResultsThis procedure was performed in five patients for harvesting of approximately 8- and 5-cm lengths of the parietal and frontal branches, respectively. The resultant lengths of the harvested vessels were sufficient for anastomotic revascularization of MCA recipient arteries in both the frontal and temporal lobes.ConclusionThis method can be safely performed with achievement of a less invasive dissection of the STA and an overall improved cosmetic outcome.

Pressure gradients between intraluminal and extraluminal spaces may affect the potassium induced contraction in the rabbit’s basilar arteries

In order to investigate the different contactile effects between intraluminal and extraluminal vasoactive agents, we studied the contractile responses of rabbit basilar artery to selective intraluminal and extraluminal administration of potassium, serotonin and histamine in vitro. We also studied how the physical pressure gradients, such as hydrostatic or osmotic pressure gradients between intraluminal and extraluminal spaces, affect potassium-induced contraction. Intraluminal potassium (30 mM) induced a significantly greater contraction than extraluminal potassium. Serotonin (2 x 10(-7) M) and histamine (10(-5) M) applied intraluminally caused the same magnitude of the contraction as those applied extraluminally and no significant differences were noted between these applications. These differences in potassium-induced contraction were more significant when the intraluminal hydrostatic pressure was elevated by 20 mmHg. Contraction by either intraluminal or extraluminal potassium was significantly decreased when intraluminal pressure was raised by 40 mmHg. As the osmotic pressure gradients between the extraluminal and the intraluminal spaces were increased, these differences in potassium-induced contraction were decreased. Our findings suggest that physical pressure gradients may affect potassium-induced contraction in a different manner from pharmacologically-induced contraction and that free ions can penetrate the vascular wall by physical pressure gradients between the intraluminal and extraluminal spaces of cerebral artery.

Endoscopic third ventriculostomy for hydrocephalus due to unruptured pineal AVM: case report and review of the literature.

INTRODUCTION Arteriovenous malformations (AVM) are considered to be static congenital lesions; however, a subset may possess dynamic pathophysiological capabilities of growth, regression or other morphological changes with time. We report on an adult patient harboring a pineal AVM who presented with progressive symptoms of obstructive hydrocephalus and was successfully treated by endoscopic third ventriculostomy (ETV). CLINICAL PRESENTATION This 63-year-old man was incidentally diagnosed 8 years previously with an asymptomatic unruptured pineal AVM and followed conservatively until he developed a progressive impairment in consciousness with gait apraxia and incontinence over a period of 2 months. Magnetic resonance imaging (MRI) revealed obstructive hydrocephalus due to nidal compression at the level of the aqueduct. Treatment by ETV resulted in resolution of neurological deficits and ventriculomegaly without evidence of complications at 18-months follow-up. CONCLUSION Treatment by ETV in adults with obstructive hydrocephalus due to deep pineal AVMs is a reasonable option in selected cases. A discussion of the pathological mechanisms and therapeutic options for this rare entity is presented.