Anterior clinoidal meningiomas: report of a series of 33 patients operated on through the pterional approach.
(9/145)
Between 1985 and 1995, 33 cases of clinoidal meningioma were surgically treated by pterional approach. In 6 cases, according to the grading scale of Al-Mefty, the lesions were group I, having originated from the lower part of the clinoid; in 22 cases, the lesions were group II, having originated from the upper or lateral part of the clinoid process; and in 5 cases, the lesions were group III since they arose from the optic foramen. Postoperatively, 17 patients showed an improvement, 4 were unchanged, and 6 presented further deficits. Five patients died after surgery: two from pulmonary thromboembolism, one from myocardial infarction, one from hematoma of the operative field, and one from cerebral ischemia after severe vasospasm of the internal carotid artery (unresponsive to treatment). The mean follow-up was 53.7 months (range 12-108 months) and included 19 patients. During this period, there were five recurrences, and three patients underwent resection again and showed no signs of tumor regrowth 1 year later; one patient who did not undergo resection again due to his age and poor general conditions died 3 years after onset of the recurrence; the last patient has so far refused a second operation. The clinical, diagnostic, and therapeutic aspects of this not infrequent pathology are discussed in the light of our experience and the pertinent literature. (+info)
Dominant localization of prostaglandin D receptors on arachnoid trabecular cells in mouse basal forebrain and their involvement in the regulation of non-rapid eye movement sleep.
(10/145)
Infusion of prostaglandin (PG) D(2) into the lateral ventricle of the brain induced an increase in the amount of non-rapid eye movement sleep in wild-type (WT) mice but not in mice deficient in the PGD receptor (DP). Immunofluorescence staining of WT mouse brain revealed that DP immunoreactivity was dominantly localized in the leptomeninges (LM) of the basal forebrain but that PGD synthase immunoreactivity was widely distributed in the LM of the entire brain. Electron microscopic observation indicated that DP-immunoreactive particles were predominantly located on the plasma membranes of arachnoid trabecular cells of the LM. The region with the highest DP immunoreactivity was clearly defined as bilateral wings in the LM of the basal forebrain located lateral to the optic chiasm in the proximity of the ventrolateral preoptic area, one of the putative sleep centers, and the tuberomammillary nucleus, one of the putative wake centers. The LM of this region contained DP mRNA 70-fold higher than that in the cortex as judged from the results of quantitative reverse transcription-PCR. PGD(2) infusion into the subarachnoid space of this region increased the extracellular adenosine level more than 2-fold in WT mice but not in the DP-deficient mice. These results indicate that DPs in the arachnoid trabecular cells of the basal forebrain mediate an increase in the extracellular adenosine level and sleep induction by PGD(2). (+info)
A 65-year-old woman presented with a ruptured saccular aneurysm associated with a rare variation of the posterior communicating artery (PcoA), partially duplicated PcoA. The PcoA with this variation forked just distal to the aneurysmal neck, and the two branches independently merged into the posterior cerebral artery. Initial clipping failed to isolate the aneurysm from one of the two branches, so the aneurysmal dome continued to pulsate and bleed. Temporary clipping of the proximal internal carotid artery revealed the fork of the two branches just distal to the aneurysmal neck. A curved Yasargil clip was used to clip the aneurysm and preserve the PcoA and branches. Careful observation of this PcoA variation is needed because the arterial structures may be hidden by the thickened arachnoid membrane. (+info)
Nf2 gene inactivation in arachnoidal cells is rate-limiting for meningioma development in the mouse.
(12/145)
Biallelic NF2 gene inactivation is common in sporadic and in neurofibromatosis type 2 (NF2)-related meningiomas. We show that, beginning at four months of age, thirty percent of mice with arachnoidal cell Cre-mediated excision of Nf2 exon 2 developed a range of meningioma subtypes histologically similar to the human tumors. Additional hemizygosity for p53 did not modify meningioma frequency or progression suggesting that Nf2 and p53 mutations do not synergize in meningeal tumorigenesis. This first mouse model initiated with a genetic lesion found in human meningiomas provides a powerful tool for investigating tumor progression and for the preclinical evaluation of therapeutic interventions. (+info)
A case of spinal cord compression, presumed to be due to a calcification in the arachnoid, is presented. Its relationship to a previous spinal subarachnoid haemorrhage is mentioned. The literature is reviewed and the relationship of this condition to spinal subarachnoid haemorrhage, previous myelogram, and spinal anaesthetic is stressed. (+info)
Macrophages related to leptomeninges and ventral nerve roots. An ultrastructural study.
(14/145)
In immature rats active macrophages were frequently seen projecting into the subarachnoid space from the surface of the leptomeninges. They also occurred between the layers of the pia and within the nerve roots. They were most frequent during the first two weeks after birth, which is a period of rapid neural growth and myelination in ventral roots. In contrast, they were much fewer at later stages. The ultrastructural characteristics of these cells are described. It is suggested that these cells take part in tissue growth and remodelling by the removal of material which degenerates or becomes redundant during development. For example, they may ingest effete leptomeningeal cells or fragments of them. Those within the ventral roots may phagocytose abnormal Schwann cells, or the myelin of sheaths which have failed to develop normally. It is also suggested that macrophages may be involved in the excavation of the subarachnoid space. Another possible function in which they may be involved is the ingestion of material, possibly of a protein nature, from the cerebrospinal fluid. (+info)
Pontine glioblastoma multiforme initially presenting with leptomeningeal gliomatosis.
(15/145)
A 49-year-old female presented with diffuse leptomeningeal gliomatosis as the initial manifestation of pontine glioblastoma. Magnetic resonance imaging initially revealed diffuse leptomeningeal enhancement caused by metastatic deposits, predominantly along the basal cistern and bilateral sylvian fissures. The primary pontine lesion appeared as hypointense on T1-weighted imaging and hyperintense on T2-weighted imaging, but with no enhancement by gadolinium-diethylenetriaminepenta-acetic acid. There was no diffuse enlargement of the pons. The patient died 11 months after the initial presentation. The primary lesion in the pons was histologically confirmed at autopsy. Diffuse enhancement of leptomeningeal dissemination may occur as the initial manifestation of non-enhanced pontine glioblastoma. (+info)
Extensive oligonucleotide microarray transcriptome analysis of the rat cerebral artery and arachnoid tissue.
(16/145)
Cerebral vessels have certain distinct anatomical and developmental characteristics which are well known, but their characteristic genetic expression profile remains as yet only poorly understood. We investigated gene expression in the rat cerebral artery in comparison with the rat descending aorta, two locations which have obviously different anatomical and developmental characteristics. Since the contamination of cerebral small arteries by arachnoid tissue is to a certain extent inevitable, we also performed a gene expression analysis of arachnoid tissue as a background. In an effort to obtain the necessary quality and quantity of total RNA, a novel freeze-fracture apparatus minimizing the time required for the entire procedure from tissue separation to RNA preparation was used. With the material obtained, a group of genes highly expressed in each tissue was detected by oligonucleotide microarray analysis. In the circle of Willis, peptide-19 (PEP-19), connexin-37 (CXN-37), growth arrest-and DNA damage-inducible gene (GADD45), and the putative G protein coupled receptor RA1c, Notch-1, and jagged-1 were predominantly expressed. In arachnoid tissue, bone morphologic protein (BMP)-7, BMP-6, beta defensin-1, neuroendocrine protein 7B2, thiol-specific antioxidant protein, IL-18, beta-chain clathrin-associated protein complex AP-1, and angiopoietin-2 were highly expressed. In the aorta, most of the abundantly expressed genes related to lipid metabolism. By means of oligonucleotide microarray analysis, the distinct gene expression profiles in the circle of Willis arachnoid tissue, and aorta were made evident. From these findings it is reasonable to conclude that a functional interaction exists between the circle of Willis and arachnoid tissue. (+info)