Masayuki Miyazono

Trigeminal neuralgia caused by venous compression.

OBJECTIVE:The purpose of this study is to clarify whether venous compression on the trigeminal nerve really causes trigeminal neuralgia or not, and to identify which veins are the offending veins. METHODS:We used microvascular decompression in operations on 121 patients with typical trigeminal neuralgia. We analyzed the intraoperative findings and surgical results in these 121 cases. RESULTS:In 7 of the 121 cases, only the vein was identified as a compressive factor on the trigeminal nerve. In 6 of these 7 cases, single venous compression was found, whereas the remaining case had two offending veins. The transverse pontine vein was most frequently found as the offending vein near Meckel’s cave. All patients showed complete relief of trigeminal pain after decompression of the veins, but four of them developed facial numbness after surgery, which tended to be slight and did not require any treatment. CONCLUSION:Our surgical experiences showed that venous compression could cause trigeminal neuralgia by itself and that the transverse pontine vein should be carefully observed because it is most frequently the offending vein.

Preferential expression of αB-crystallin in astrocytic elements of neuroectodermal tumors

Recently the authors have identified a major component of Rosenthal fibers as αBcrystallin, a major lens protein. In the current study the authors investigated the expression of αB‐crystallin in four cultured glioma cell lines and in 115 human neuroectodermal tumors. αB‐crystallin was expressed differentially by those glioma cell lines, but not by neuroblastoma cell lines. Northern blot analysis revealed two distinct messages for αB‐crystallin in C‐6, whereas only a single message in U‐373MG and G26‐24. In human surgical specimens positive immunostaining was frequently observed in the following brain tumors: pilocytic astrocytoma of the juvenile type, anaplastic astrocytoma, glioblastoma multiforme, and subependymal giant cell astrocytoma. The astrocytic elements of mixed oligoastrocytomas, glioblastomas with sarcomatous components, and gangliogliomas were likewise strongly stained. In contrast, little immunoreactivity was observed in ependymal and choroid plexus tumors. Thus, αB‐crystallin is mainly expressed by astrocytic tumors among neuroectodermal neoplasms, without regard to the presence of Rosenthal fibers. Cancer 68:2230–2240, 1991.

Colocalization of prion protein and β protein in the same amyloid plaques in patients with Gerstmann-Sträussler Syndrome

SummaryWe examined paraffin-embedded brain sections from three patients with Creutzfeldt-Jakob disease (CJD) and four patients with Gerstmann-Sträussler syndrome (GSS) who also had β protein deposits in the brains. Immunostaining using anti-prion protein (PrP) and anti-β protein coupled with formic acid pretreatment, revealed PrP deposits and β protein deposits, respectively. In all four GSS patients examined, sequential double immunostaining and single immunostaining in serial sections or simultaneous double immunofluorescence revealed the colocalization of PrP and β protein in the same amyloid plaques. The plaques labeled with both antibodies were designated as β-PrP plaques. Small kuru plaques of less than 15 μm in diameter were rarely found to coexist with β deposits. The percentages of β-PrP plaques in larger kuru plaques were not constant among the four GSS patients. The colocalization patterns of both deposits were observed as being roughly of two types as follows: (1) diffuse β protein deposits located around the PrP core; and (2) a β protein core and PrP core simultaneously existing in one amyloid plaque. Under an electron microscope, we were able to confirm the presence of both β protein and PrP in a single plaque in four GSS patients older than 60 years old. In contrast, no colocalization of either deposits was seen in the amyloid plaque core fractions of a young GSS patient who had no β protein deposits, even at the electron microscopic level. Therefore, the colocalization of both proteins in a single plaque is believed to be age-related and incidental in GSS patients but suggests a similar morphogenesis of both amyloid deposits.

Creutzfeldt-Jakob disease with codon 129 polymorphism (Valine): a comparative study of patients with codon 102 point mutation or without mutations

SummaryWe examined 7 patients with Creutzfeldt-Jakob disease (CJD) with a methionine-to-valine change at prion protein (PrP) codon 129 (CJD129 patients). These CJD129 patients did not have either a condon 117 or 198 point mutation. For comparison, we also examined 7 patients with Gerstmann-Sträussler syndrome (GSS) with a proline-to-leucine change at PrP codon 102 (GSS102 patients) and 13 patients without any known mutations at codons 102, 117, 129, 178, or 200 (CJDwild patients). CJD129 patients had a long clinical duration and ataxia at onset, but rarely had any periodic synchronous discharge in their electroencephalogram. Unlike CJDwild patients, all CJD129 patients have typical congophilic PrP plaques in their brain. These clinicopathological findings were similar to those of GSS102. However, the distribution and morphology of PrP deposits revealed by immunohistochemistry were different between CJD129 and GSS102. In GSS102 more numerous and various types of PrP plaques are seen throughout the brain, while in CJD129 patients a unicentric core was the major feature of PrP plaques. The change in codon 129 influences the clinical course and pathological findings in CJD.

Effects of single low dose irradiation on subventricular zone cells in juvenile rat brain.

Abstract Although the juvenile human brain is relatively radioresistant, irradiation can result in brain growth retardation, progressive mental disturbance, and neurologic abnormalities. As neural stem cells or progenitor cells may be a target of radiation injury and may play an important role in the brains functional recovery, we examined the effects of whole brain irradiation on these cells in juvenile rat. Six-week-old Wistar rats, where the brain is still growing, were irradiated with single doses of 1, 2, or 3 Gy X-ray. We measured their body and brain weights at 30 or 60 days after irradiation. The chronological changes of the subventricular zone (SVZ) were examined at 6 h, 2, 7, 14, 30, or 60 days after irradiation by immunohistochemistry, specifically looking at the neural stem cells or progenitor cells using anti-nestin antibodies specific for these cells. The rate of brain weight gain of irradiated rats significantly decreased in comparison to controls, although that of body weight gain was similar among them. Multiple apoptotic cells appeared in the SVZ at 6 h after irradiation with simultaneous reduction in nestin-positive cells (69% of the control). The cell levels recovered within a week, with the nestin-positive cells reaching maximal numbers (182%) on Day 14. Nestin-positive cells returned to baseline levels within 30 days (96%) and remained unchanged for the subsequent 60 days. The X-ray dosage did not affect these findings. Our findings revealed that single low dose X-ray administration reversibly affected the levels of neural stem and progenitor cells in the SVZ region. These results suggest that continuous multiple administrations of X-rays in clinical treatment may affect irreversible changes on neural stem or progenitor cells, causing brain growth retardation, or dysfunction.

Astrocytoma of the pituitary gland (pituicytoma): case report

Abstract. A 34-year-old man presented with a 4-month history of visual obscuration. Magnetic resonance imaging showed a solid, discrete, contrast-enhancing pituitary mass with suprasellar extension. Surgery, which was performed via a transsphenoidal approach, disclosed the pituitary tumor to be a fibrillary astrocytoma (pituicytoma). This case report contains the clinical and neuroimaging features of this rare tumor of the neurohypophysis, which masqueraded as a pituitary adenoma.

Three-dimensional CT angiography for the surgical management of the vertebral artery-posterior inferior cerebellar artery aneurysms

SummaryBackground. Surgery of vertebral artery-posterior inferior cerebellar artery (VA-PICA) aneurysms is not easy because there is a close anatomical relationship between aneurysms and the surrounding neurovascular structures, and bony structures in the lateral foramen magnum. The preoperative evaluation for a circumstantial comprehension of anatomical relationships is very important for the surgical treatment of the VA-PICA aneurysms. Our experience in using three-dimensional CT angiography (3D-CTA) for the surgical management of VA-PICA aneurysms is herein reported. Methods and findings. We successfully performed neck clipping in 5 cases of VA-PICA aneurysm using 3D-CTA. On 3D reconstructed images, we could see the characteristics of the aneurysms such as their relationships to the jugular tubercle and hypoglossal canal, the projecting direction of the dome, and the configuration of the neck in each case. 3D-CTA also provided a clear surgical view as well as the relationships of the aneurysms to the VA and origin of the PICA. Based on such information, we selected the most appropriate surgical approach among the transcondylar fossa approach, the transcondylar approach, or the far lateral approach with a C1 laminectomy. Conclusions. Since 3D-CTA demonstrates the surgical anatomy of VA-PICA aneurysms in detail, it is very useful for helping surgeons to select the optimal approach.

Widespread distribution of tau in the astrocytic elements of glial tumors

SummaryRecently tau immunoreactivity has been observed in astrocytes in Alzheimers disease and other neurological diseases. We examined the immunohistochemical localization of tau in 110 human brain tumors. Tau was widely distributed in the glial neoplastic cells and the reactive astrocytes in tumor tissues. In human surgical specimens positive immunostaining for tau was frequently observed in astrocytic tumors, oligodendroglial tumors, and glioblastoma, as well as neuronal tumors. The astrocytic neoplastic cells in medulloblastoma and other poorly differentiated tumors were also stained. In contrast, no immunoreactivity was observed in meningiomas and schwannomas. The expression of tau in brain tumors was mainly restricted to those cells with astrocytic features rather than small immature cells. The expression of tau mRNA was also demonstrated in astrocytic tumors. In conjunction with the findings of tau-positive astrocytes in some degenerative disorders, astrocytes are considered to have a potential to express tau through neoplastic transformation and reactive processes.

Two surgical cases of internal carotid- ophthalmic artery aneurysms: Special reference to the usefulness of three-dimensional CT angiography

Abstract Three-dimensional computerized tomography angiography (3D-CTA) is a noninvasive tool for the diagnosis of cerebral aneurysms. 3D-CTA is helpful in the evaluation of the configuration of aneurysms and their surrounding vessels and anatomical structures. The aim of this study is to assess the usefulness of 3D-CTA for patients with unruptured internal carotid-ophthalmic artery aneurysms. We pre-operatively obtained surgical simulation images using 3D-CTA and 3D reconstruction and then compared them with magnetic resonance angiography (MRA), conventional cerebral angiography and operative findings in the patients. Two patients with unruptured internal carotid-ophthalmic artery aneurysm were selected. These patients underwent direct neck clipping after the optic canal was unroofed through a combined epidural-subdural approach. The cerebral aneurysm was detected by 3D-CTA, MRA and conventional cerebral angiography in each case. Only by 3D-CTA, however, could we easily detect the relationships among the aneurysm neck, ophthalmic artery and optic canal. Based on this information, direct clipping operations were performed safely without any complications. 3D-CTA is an excellent noninvasive diagnostic method not only for detecting cerebral aneurysms, but also for evaluating the relationships between the aneurysms and surrounding structures.

Fibroxanthoma arising from the cranial dura mater

Abstract A primary xanthomatous tumor is very rare in the central nervous system (CNS). Here we report the case of a fibroxanthoma arising from the dura mater of the cerebrum that demonstrated no systemic disease or metabolic abnormalities. A 19-month-old, otherwise healthy boy was found to have an enlarged head. Magnetic resonance imaging demonstrated a left occipital dural mass lesion and an enlarged left cerebral hemisphere with ipsilateral ventricular enlargement. Subtotal removal of the tumor was performed through the left parieto-occipital craniotomy. The tumor was composed of a central fibrous portion, a peripheral xanthomatous area, and a boundary. The peripheral area of the tumor showed abundant uniform xanthomatous cells with a thin fibrous stroma and the mass was diagnosed as fibroxanthoma involving the dura. This may represent a distinct category of tumor, which is different from the previously reported cases of fibrous xanthoma and fibrous histiocytoma. Intracranial xanthomatous tumors may be heterogeneous in their origin and histological features. However, further studies are needed to elucidate their clinical features, biological behavior, and optimal treatment strategies.