Neurofibromatosis 2 gene has novel alternative splicings which controls intracellular protein binding

Three novel isoforms of the neurofibromatosis 2 (NF2) gene transcripts generated from alternative splicing were identified from normal human brain, schwannoma and glioma tissues. The 3 novel transcripts lack exon 2, exons 2 and 3, exons 2-4, respectively. Recombinant isoform proteins encoded by those new transcripts have lost the previously reported ability to bind S-35-methionine labeled cellular proteins. Two of seven glioblastoma tissues expressed significantly high levels of the shorter transcripts whereas low grade astrocytomas expressed levels similar to those found in normal brain, suggesting that genomic mutation or aberrant alternative splicing of the NF2 gene may contribute to the progression of malignant gliomas.

Increased monocyte chemoattractant protein-1 expression by tumor necrosis factor-alpha can mediate macrophage infiltration in gliomas

We compared the in vitro effects of various cytokines on the expression of monocyte chemoattractant protein-1 (MCP-1) in glioma cell lines and found that MCP-1 expression was highly induced by tumor necrosis factor-alpha (TNF alpha) and interleukin-1 beta. The intra-tumoral injection of TNF alpha in rat glioma model increased the in vivo expression of MCP-1 at 1 to 12 h after the injection and induced macrophage infiltration into tumor tissue. The injection of TNF alpha into post-operative tumor cavity of human malignant glioma also increased the concentration of MCP-1 in the cavity fluid at 24 to 38 h after injection. These data, together with the previous finding that the growth of transplanted MCP-1-transfected cells was significantly inhibited by infiltrated macrophages, suggest that injection of TNF alpha inhibits turner growth via the induction of MCP-1 expression.

Magnetic resonance imaging of pilocytic astrocytomas: usefulness of the minimum apparent diffusion coefficient (ADC) value for differentiation from high-grade gliomas

BACKGROUND

On contrast-enhanced magnetic resonance (MR) images, pilocytic astrocytomas (PAs) are usually well-enhanced tumors that may mimic high-grade gliomas (HGGs). On the other hand, it has been suggested that areas exhibiting minimum apparent diffusion coefficient (ADC) values reflect the sites of highest cellularity within heterogeneous tumors.

PURPOSE

To test the hypothesis that the cellularity of PAs is significantly different to the cellularity of HGGs, which should result in significant differences in minimum ADC values.

MATERIAL AND METHODS

Between 1999 and 2005, 15 patients (nine males, six females) with histopathologically confirmed PAs underwent pretreatment MR examination including diffusion-weighted (DW) imaging. We reviewed their MR findings with respect to the size, location, morphology, contrast enhancement, and minimum ADC value of the tumors. The minimum ADC values of the 15 PAs were compared with those of 104 HGGs diagnosed during the same period.

RESULTS

The diameter of the 15 PAs ranged from 11 to 60 mm (mean 36 mm); all were located around the ventricles, and all contained enhancing components. All except two small (11 and 14 mm) PAs contained cystic components. The minimum ADC values were significantly higher in PAs (median 1.688, range 1.375-1.897 x 10(-3) mm(2)/s) than HGGs (0.997, 0.543-2.024 x 10(-3) mm(2)/s) (P < 0.0001), although there was substantial overlap. Among the tumors with enhancing components, all but one PA were differentiated from the 76 HGGs with enhancing components (0.922, 0.543-1.462 x 10(-3) mm(2)/s) when the minimum ADC cutoff value was set at 1.5 x 10(-3) mm(2)/s.

CONCLUSION

The minimum ADC value may be helpful for the differentiation between PAs and HGGs. A tumor with enhancing components should be PA instead of HGG when the minimum ADC value is higher than 1.5 x 10(-3) mm(2)/s.

Differentiation between paraclinoid and cavernous sinus aneurysms with contrast-enhanced 3D constructive interference in steady- state MR imaging

BACKGROUND AND PURPOSE

Differentiation between paraclinoid and cavernous sinus aneurysms of the internal carotid artery (ICA) is critical when considering treatment options. The purpose of this study was to determine whether contrast-enhanced (CE) 3D constructive interference in steady state (CISS) MR imaging is useful to differentiate between paraclinoid and cavernous sinus aneurysms.

MATERIALS AND METHODS

This study included 11 aneurysms in 10 consecutive female patients, ranging from 52 to 66 years of age. All aneurysms were adjacent to the anterior clinoid process. After conventional and CE 3D-CISS imaging on a 1.5T MR imaging unit, all patients underwent surgery, and the relationship between the aneurysms and the dura was confirmed. Two neuroradiologists evaluated the location of the aneurysms on CE 3D-CISS images and classified them as intradural, partially intradural, and extradural aneurysms. Operative findings were used as a reference standard. To understand the imaging characteristics, we assessed the boundary and signal intensity of the cavernous sinus, CSF, and carotid artery on the side contralateral to the lesion.

RESULTS

Operative findings disclosed that 5 aneurysms were intradural and 6 were extradural. All except 2 were accurately assessed with CE 3D-CISS imaging. One intradural aneurysm adjacent to a large cavernous aneurysm and 1 cavernous giant aneurysm were assessed as partially intradural. On CE 3D-CISS images, the boundary between the CSF, cavernous sinus, and carotid artery was identified by high signal-intensity contrast in all cases.

CONCLUSION

CE 3D-CISS MR imaging is useful for the differentiation between paraclinoid and cavernous sinus aneurysms.

External Manual Carotid Compression is Effective in Patients with Cavernous Sinus Dural Arteriovenous Fistulae

SUMMARY

External manual carotid compression is a non-invasive method to treat patients with cavernous sinus dural arteriovenous fistulae (CSDAVF). We studied a group of patients with CSDAVF to identify factors that made cure by compression therapy possible. We treated 23 patients with CS-DAVF without cortical venous drainage or a recent decline in visual acuity by compression therapy. All were followed up by magnetic resonance angiography (MRA) at one, three, six, and 12 months after treatment and the characteristics of the imaging findings, their neurological symptoms, and the patterns of symptom improvement were examined. In group A (n=8), cure was achieved by manual carotid compression; in the other 15 patients (group B), cure was not obtained. Group B manifested significantly higher ocular pressure and a significantly longer interval between symptom onset and treatment by manual carotid compression. In group A, venous drainage was via the superior orbital vein (SOV) with/without involvement of the inferior petrosal sinus (IPS); closure of the CS-DAVF occurred within 4.1 months after the start of treatment. In three patients symptom improvement progressed steadily and gradually. The other five cured patients experienced transient worsening of their symptoms at two to four months after the start of treatment, these resolved within four to seven months. Manual carotid compression was effective in patients without retrograde venous CS-DAVF drainage or a severe decline in visual acuity. The factors that rendered cure by compression therapy possible were lower ocular pressure and a shorter interval between symptom onset and the start of treatment. Venous drainage in those patients was exclusively via the SOV without involvement of the IPS.

Multiple prominent dilated perivascular spaces do not induce Wallerian degeneration as evaluated by diffusion tensor imaging

It is unknown whether dilated perivascular spaces can affect the adjacent neuronal fibers. We describe conventional MR and diffusion tensor imaging findings of a case with multiple, prominent dilated perivascular spaces in the left cerebral hemisphere. Diffusion tensor imaging showed no alterations in the fractional anisotropy and apparent diffusion coefficient values for the corona radiata, posterior rim of the internal capsule, and the cerebral peduncle, indicating no wallerian degeneration associated with dilated perivascular spaces.

Evaluation of the Stability of Small Ruptured Aneurysms with a Small Neck after Embolization with Guglielmi Detachable Coils. Correlation between Coil Packing Ratio and Coil Compaction

SUMMARY

It is difficult to predict the compaction of Guglielmi detachable coils (GDC) after endovascular surgery for aneurysms. Therefore, we studied the relationship between the coil packing ratio and compaction in 62 patients with acute ruptured intracranial aneurysms that were small (< 10 mm) had a small neck (< 4 mm) and were coil-embolized with GDC-10. We recorded the maximum prospective coil length, L, as the length that correspond with the volume of packed coils occupying 30% of the aneurysmal volume. L was calculated as L (cm) = 0.3 x a x b x c and the coil packing ratio expressed as packed coil length/L x 100, where a, b, and c are the aneurysmal height, length, and width in mm, respectively. Angiographic followup studies were performed at three months and one and two years after endovascular surgery. Of the 62 patients, 16 (25.8%) manifested angiographic coil compaction (ten minor and six major compactions); the mean coil packing ratio was 51.9 +/- 13.4%. The mean coil packing ratio in the other 46 patients was 80.5 +/- 20.2% and the difference was statistically significant (p < 0.01). In all six patients with major compaction the mean packing ratio was below 50%. We detected 93.8% of the compactions within 24 months of coil placement. In patients with small, necked aneurysms, the optimal coil packing ratio could be identified with the formula 0.3 x a x b x c. The probability of compaction was significantly higher when the coil packing ratio was under 50%. To detect coil compaction post-embolization, follow-up angiograms must be examined regularly for at least 24 months.

Serial changes in the regional cerebral blood flow of patients with hypertensive intracerebral hemorrhage -- long-term follow-up SPECT study

We analyzed serial changes in the regional cerebral blood flow (rCBF) of 13 patients with intracerebral hemorrhage by single photon emission computed tomography (SPECT) during the acute- to chronic stage (2 hr to 55 weeks). The (99m)Tc-ethyl cysteinate dimmer ((99m)Tc-ECD) was used as the nuclear mediator. The SPECT timing within 48 hours after the onset was considered to be acute stage, from 48 hours to 4 weeks to be subacute stage, and after 4 weeks to be chronic stage. The region of interest was each hemisphere in the whole brain without ventricles at the thalamic level. For semi-quantitative analysis of rCBF, we used the Brain Uptake Ratio method. Of the 13 patients (mean age 65.5 years), 3 had thalamic-, 4 putaminal-, 5 subcortical-, and one a cerebellar hemorrhage; the hematoma volume varied from 4-50 ml (<20 ml, n=9; 20-30 ml, n=1; >30 ml, n=3; mean 17 ml). The rCBF changes during the long-term follow-up were classified as increase-, decrease-, and unchanged type. Of 5 patients with increased rCBF, 4 made a good recovery and one was severely disabled; of 5 patients with decreased rCBF, 1 made a good recovery, 3 were moderately-, and one was severely disabled. All 3 patients with unchanged rCBF were moderately disabled. Our findings suggest that among patients with hypertensive intracerebral hemorrhage, those with increased rCBF over time may have a favorable outcome. We further need more cases with intracerebral hemorrhage to clarify this trend.

Clinico-pathological study of meningiomas with haemorrhagic onset

BACKGROUND

Haemorrhage from meningiomas is rare and the underlying pathophysiological mechanisms remain to be determined. We sought to identify these mechanisms by studying clinical and histological records of 6 meningioma patients treated at our institution.

PATIENTS AND METHODS

We retrospectively studied 6 patients with meningiomas whose acute onset was due to haemorrhage. We evaluated clinical features and imaging studies. The vascularity and proliferative nature of these tumours were examined immunohistochemically and tissue factor (TF) immunoreactivity was assessed. For comparison we evaluated 25 non-haemorrhagic meningiomas.

FINDINGS

At onset, the haemorrhages mimicked stroke in all 6 patients. On imaging studies, 3 of the haemorrhages were intra- and extratumoural, the other 3 were extratumoural only. Hyperintensity on T2-weighted MRI was a characteristic of these meningiomas. Histologically, they were of 3 subtypes, meningothelial (n=3), transitional (n=2), and anaplastic (n=1). The MIB-1 labelling index of the 5 WHO Grade I meningiomas was 5.8+/-2.2. The mean number of CD31-positive blood vessels did not differ in haemorrhagic and non-haemorrhagic meningiomas. The TF-positivity rate of haemorrhagic meningiomas was higher than of non-haemorrhagic meningiomas.

INTERPRETATION

The proliferative nature of the meningiomas and TF expression in tumour cells may have contributed to the eventual haemorrhage of the meningiomas in our series.

Hydroxyapatite and bFGF Coating of Detachable Coils for Endovascular Occlusion of Experimental Aneurysm

SUMMARY

The purpose of this study was to evaluate the effect of hydroxyapatite (HAp) and fibroblast growth factor-basic (bFGF) coating on Guglielmi detachable coils (GDCs) in an experimental aneurysm model. A total of 18 aneurysms were experimentally made in the common carotid arteries of swine. Embolization was done on these aneurysms using standard GDCs and coated GDCs with HAp (GDC-HAp) and with bFGF (GDC-HAp-bFGF). The animals were then killed 14 days after embolization. The development of tissue scarring and coverage the aneurysm's orifice were evaluated macroscopically. No significant difference of volume ratio of the coils exited in each groups. Macroscopically, covering ratio of fibrous membrane at the neck of aneurysms were 88.3 +/- 14.7% in a group with GDC-HAp-bFGF, while it were 26.7 +/- 15.3% in a group with standard GDC and it was 41.7 +/- 31.7% in a group with GDC-HAp. These results indicated that coating by hydroxyapatite and bFGF might facilitate a wound healing in an experimental aneurysm model.

Hydroxyapatite coating of detachable coils for endovascular occlusion of experimental aneurysm

SUMMARY

The purpose of this study was to evaluate the effect of hydroxyapatite (HAp) coating on Guglielmi detachable coils (GDCs) in an experimental aneurysm model. A total of 12 aneurysms were experimentally made in the common carotid arteries of swine using a microsurgical technique. Embolization was done on these aneurysms using standard GDCs and GDCs coated with HAp (GDC-HAp). The animals were then killed 14 days after embolization. The physical properties of coated coils and the development of tissue scarring and coverage the aneurysm's orifice were evaluated macroscopically and microscopically. Macroscopically, a scar formation and coverage at the neck of aneurysms were observed in a group with GDC-HAp, while such findings were not seen in a group with GDC. With light microscope, fibroblasts were seen in the neck of the aneurysms in a group using GDC-HAp, whereas only a fibrin- like net was seen in a group using GDC. In a group with GDC-HAp, inflammatory response was more intense in the dome of the aneurysm with faster re-endothelial coverage of the neck of the aneurysm than the ones in a group with GDC. These results indicated that GDC-HAp might create a clinically beneficial biological surface in an experimental aneurysm model.

A case of non-functioning pituitary adenoma with Cushing's syndrome upon recurrence

A 49-year-old woman presented with left visual disturbance. No signs of Cushing's disease were evident. Basal levels of serum cortisol and plasma adrenocorticotropic hormone (ACTH) were 16.8 microg/dL and 66.0 pg/mL, respectively. MRI demonstrated an irregularly shaped large pituitary tumor, and the patient then underwent transsphenoidal surgery. By light microscopy the tumor represented a chromophobic adenoma with a few of the adenoma cells showing immunoreactivity for ACTH. On the basis of clinical and light microscopic examinations, the diagnosis of silent corticotroph adenoma was made. Electron microscopy, however, demonstrated the honeycomb Golgi complex that has been reported as a typical finding of gonadotroph adenomas. MRI taken 7 months after the first operation revealed adenoma regrowth. Transcranial surgery was performed, and histology demonstrated a chromophobic pituitary adenoma with most cells immunopositive for ACTH. She was treated with gamma knife postoperatively. Three months later, MRI revealed remarkable shrinkage of the adenoma, but she developed typical signs and symptoms of Cushing's disease. Thus, the hormone immunostaining and biological activity of pituitary adenomas may change with time.

Analysis of loss of heterozygosity on chromosome 10 in patients with malignant astrocytic tumors: correlation with patient age and survival

OBJECT

The most frequent genetic abnormality in human malignant gliomas is loss of heterozygosity (LOH) on chromosome 10. Candidate genes on chromosome 10 that are associated with the prognosis of patients with anaplastic astrocytoma (AA) and glioblastoma (GBM) were evaluated.

METHODS

The authors used 12 fluorescent microsatellite markers on both arms of chromosome 10 to study LOH in 108 primary astrocytic tumors. The LOH on chromosome 10 was observed in 11 (32%) of 34 AAs and 34 (56%) of 61 GBMs. No LOH was detected in 13 low-grade gliomas. Loss of heterozygosity was not detected in any AA in the seven patients younger than 35 years, but it was discovered in 41% of the patients older than 35 years. The prognostic significance of LOH at each locus was evaluated in 89 patients older than 15 years; 33 (37%) had supratentorial AAs and 56 (63%) had supratentorial GBMs. The Cox proportional hazards model, adjusted for patient age at surgery, the preoperative Karnofsky Performance Scale score, and the extent of surgical resection revealed that LOH on marker D10S209 near the FGFR2 and DMBT1 genes was significantly associated with shorter survival in patients with AA. The LOH on markers D10S215 and D10S541, which contain the PTEN/MMAC1 gene between them, was significantly associated with shorter survival in patients with GBM.

CONCLUSIONS

In the present study it is found that LOH on chromosome 10 is an age-dependent event for patients with AAs and that LOH on marker D10S209 near the FGFR2 and DMBT1 loci is a significantly unfavorable prognostic factor. It is also reported that LOH on the PTEN/MMAC1 gene is a significantly unfavorable prognostic factor in patients with GBM.

Metastatic brain tumours from oesophageal carcinoma: neuro-imaging and clinicopathological characteristics in Japanese patients

BACKGROUND

Since metastatic brain tumours from esophageal carcinoma are essentially rare, previous reports have not determined the common neuro-radiological findings and its clinical aspects.

FINDINGS

We report the neuro-imaging and clinicopathological features of our 8 metastatic brain tumours from an esophageal site. Histologically, 6 of our 8 patients had squamous cell carcinoma and 2 had small cell carcinoma, a rare variant form. Both histological types mainly exhibited cystic lesions with a thin enhanced rim on magnetic resonance images (MRI, 4 of 6 squamous cell carcinomas and 1 of 2 small cell carcinomas). Combination therapy (irradiation and chemotherapy) after surgical treatment, the number of metastatic brain tumours, and the interval between their appearance and the diagnosis of the primary lesion could be prognostic factors in our series.

INTERPRETATION

Among Japanese, the vast majority of primary esophageal cancers are squamous cell carcinomas. Therefore, MRI findings of a cystic tumour with a thin enhanced rim may alert one to the possibility of a metastatic brain tumour from the esophagus.

Trends in the incidence of primary intracranial tumors in Kumamoto, Japan

BACKGROUND

The introduction of modern neuro-imaging techniques, as well as various environmental factors, have been changing the incidence and the proportions of the types of clinically diagnosed intracranial tumors. The aim of this study was to determine recent trends in the occurrence of primary intracranial tumors in the residents of Kumamoto Prefecture, Japan.

METHODS

We surveyed 2129 patients who were diagnosed with primary intracranial tumors between 1989 and 1998, with histological diagnosis being obtained in 71% of the patients.

RESULTS

Of the 2129 patients, 710 (33.3%) had meningiomas, 390 (18.3%) had pituitary adenomas, 315 (14.8%) had malignant gliomas, and 208 (9.8%) had schwannomas. The overall age-adjusted incidence rates were 10.97/100,000/year (males, 9.70; females, 11.86). One hundred and nine patients (5.1%) were younger than 15 years, and 480 patients (22.5%) were older than 70 years. The most common tumors in children were astrocytomas (37.6%), followed by germ-cell tumors (16.5%) and craniopharyngiomas (11.9%), medulloblastomas (11.0%), and ependymomas (4.6%). Meanwhile, the most common tumors in elderly residents were meningioma (51.7%), followed by malignant glioma (13.7%), pituitary adenoma (11.4%), schwannoma (7.7%), malignant lymphoma (4.6%), and astrocytoma (2.7%). The proportion of asymptomatic tumors increased, from 24.6% in 1989-1994 to 33.0% in 1995-1998; 169 (62.8%) were meningiomas, followed by pituitary adenomas (14.1%).

A device for stereotactic transection of fiber bundles in rats

We have designed a device for stereotactic transection of fiber bundles in experiments using rats. Here, we present our assessment of its features relative to those of conventional methods. The instrument consists of a stainless steel cannula and a thin inner wire with a hook at one end and a hilt at the other. The hook can be extended or withdrawn freely by pushing or pulling the hilt. Lesions were evaluated in 12 male Wistar rats, after two targets, the anterior commissure (n=6) and the caudate-putamen (n=6), were transected. After the cannula was introduced into the target, the inner hook was extended in an anterior direction orthogonally to the transverse plane. Next, the entire device was pulled back along the insertion path to transect the neuronal fibers. Then the inner hook was withdrawn into the cannula and the entire device was removed. Seven days later, brains were removed for histologic processing. Microscopic examination demonstrated a slit like gap produced by transection at the target; the lesions were infiltrated by microglia and surrounded by gliosis. Adjacent regions were minimally damaged. The path of the cannula demonstrated only minimal gliosis. Unlike conventional methods, this device permits precise transection of deep fiber bundles with minimal damage to surrounding brain tissue.

Angiogenic effect of thymidine phosphorylase on macrophages in glioblastoma multiforme

OBJECT

Thymidine phosphorylase (TP) and vascular endothelial growth factor (VEGF) are known angiogenic factors; however, there are few reports in which the relationship between these two factors is addressed. The authors compared expression patterns of TP and VEGF and investigated their role in the angiogenesis of glioblastoma multiforme (GBM).

METHODS

Surgical specimens from 41 cases of GBM were immunohistochemically stained for TP, VEGF, CD68 (a macrophage marker), and CD31 (an endothelial cell marker). Both TP labeling indices and VEGF immunoreactivity displayed significant correlations with vascular density. Although VEGF was diffusely distributed in the tumor, TP was strongly expressed around blood vessels and in vascular proliferation. Double labeling for TP and CD68 in 10 cases indicated that cells that reacted strongly positive for TP were almost always macrophages, and only small numbers of CD68-negative cells weakly expressed TP. The TP messenger (m)RNA expression was investigated using reverse transcription-polymerase chain reaction in six GBMs. All six specimens expressed TP mRNA. In addition, TP mRNA was detected in two of three groups of cultured GBM cells derived from surgical specimens. Macrophages, the production of which was induced from two volunteers' peripheral blood monocytes by applying macrophage colony-stimulating factor, also expressed TP mRNA. The glioma cell lines U251MG and U87MG, which barely express TP mRNA under normal conditions, expressed TP mRNA in response to interferon-beta stimulation or while in an anoxic condition.

CONCLUSIONS

Although it is feasible that GBM cells can express TP depending on their growing conditions, the majority of TP-expressing cells present in GBMs appear to be infiltrating macrophages. Coexistence of VEGF and TP may indicate a synergistic upregulation for angiogenesis because VEGF exerts a chemotactic activity on macrophages that express TP.

Suprasellar hemangioblastoma in a patient with von Hippel-Lindau disease confirmed by germline mutation study: case report and review of the literature

BACKGROUND

Hemangioblastoma (HBL) in the suprasellar region is extremely rare.

CASE DESCRIPTION

A suprasellar mass was found in a 33-year-old woman with retinal HBL and bilateral adrenal pheochromocytomas. The diagnosis of von Hippel-Lindau (VHL) disease was confirmed preoperatively not only by these clinical manifestations but also by germline mutation study. The existence of VHL disease indicated a diagnosis of HBL for the suprasellar mass. The results of our mutation study indicated that this patient had type II VHL disease, suggesting that careful follow-up is essential for the early detection of renal cell carcinoma, which is often associated with type II VHL disease. Here, we summarize the previously reported features of sellar and suprasellar HBLs.

CONCLUSIONS

HBLs in this region may be one manifestation of VHL disease. Genetic testing of the VHL gene of our patient could provide useful information to determine appropriate medical care and management.

Dural congestion accompanying meningioma invasion into vessels: the dural tail sign

Our purpose was to verify the histological appearance of the dural tail accompanying meningiomas on MRI. We studied seven patients such a dural tale. We examined the point of attachment of the tumour and the adjacent dura mater histologically. In all patients, rich vascularity and dilated vessels were observed in the dura mater at the point of attachment of the tumour; tumour cells invaded the dura mater and vessels, packing the latter. In the adjacent dura mater, showing as a dural tail on MRI, there was tumour-cell invasion in only one patient. Vascular congestion around the vessels compacted by the tumour cells in the dura mater and dilated vessels were seen in all patients. We therefore suggest that the mechanism of the dural tail sign is as follows. First, tumour cells invade vessels and pack them at the point of tumour attachment. Then, vessel congestion is induced in the adjacent dura mater, as a result of which it enhances markedly, giving rise to the dural tail sign.

Identification of the cis-acting region in the NF2 gene promoter as a potential target for mutation and methylation-dependent silencing in schwannoma

BACKGROUND

Although mutational inactivation and allelic loss in the NF2 gene appear to be causal events in the majority of vestibular schwannomas, involvement of another potentially important mechanism, transcriptional inactivation, has not been investigated.

RESULTS

We cloned and functionally characterized the 5'-flanking region of the human NF2 gene and identified the molecular mechanisms that regulate NF2 expression. Luciferase assay and site-directed mutagenesis demonstrated that a 70-base pair (bp) region (-591 to -522 bp from the translation start site) was essential for the basic expression of the NF2 gene. A gel mobility shift assay indicated recognition by nuclear protein of the unusually long ( approximately 66 bp) sequences in this region. Recognition was inhibited by either mutation of the binding core sequence or by methylation of three CpG sites. Point mutations at these CpG sites significantly decreased promoter activity, suggesting the importance of these sites. In 14 of 23 vestibular schwannomas, these three CpG sites were methylated in a site-specific manner and the methylation status was consistent with the expression of NF2 mRNA.

CONCLUSIONS

Suppressed expression by aberrant methylation or mutation of the promoter elements could be an alternative mechanism for inactivation of the NF2 gene.

Hippocampal transection attenuates kainic acid-induced amygdalar seizures in rats

Since the dorsal and ventral hippocampus in the rat may act differently from one another in limbic seizures, we studied effects of orthogonal transection between the dorsal and ventral hippocampus upon kainic acid-induced amygdalar seizures. A total of 26 rats were divided into three groups. Ten rats underwent transection using a modified wire knife (transection group); 16 others were untransection group (n=10) and controls (n=6). All the rats then underwent stereotactic implantation of electrodes in the left amygdala (LA), left dorsal hippocampus (LdH), left ventral hippocampus (LvH), and the left sensorimotor cortex (LCx). A stainless steel cannula also was introduced into the LA. Rats except controls later received 1.0 microg of kainic acid (KA) via the cannula. Controls received phosphate buffer solution alone. In the untransection group, multiple spike discharges in the LA immediately propagated concurrently to the LvH and LdH. Propagation involved the LCx to become status epilepticus 1 to 2 h after KA injection. Seizures, characterized by mastication, salivation, facial twitching, forelimb clonus, and sometimes rearing and falling, lasted 1 to 2 days. Microscopic examination revealed severe neuronal cell damage in the LA, LvH, and LdH. In the transection group, multiple spike discharges initiated from the LA and were propagated to LvH, but LdH as well as LCx involvement was slight. Status epilepticus involved only the LA and LvH 1 to 2 h following KA injection. Seizures subsided within 24 h, showing no ictal manifestations except for aggressiveness. Overall, seizures were weak and transient compared with those in controls. Histologically, hippocampal neuronal damage was slight, but damage to amygdalar neurons was similar to that in untransection group. No electroclinical and histological changes were seen in controls. These results indicated that connections between the dorsal and ventral hippocampus are important for full development of KA-induced amygdalar seizures.

Giant chondroma arising from the dura mater of the convexity. Case report and review of the literature

Chondromas arising from the dura mater are rare intracranial tumors. The authors present a case of intracranial giant chondroma originating from the dura mater of the convexity. Neuroimaging and surgical findings are described. The diagnostic clues are discussed and similar cases from the literature are reviewed.

Inhibitory effect of epigallocatechin-gallate on brain tumor cell lines in vitro

We investigated the effect of epigallocatechin-gallate (EGCG), the main constituent of green tea polyphenols, on human glioblastoma cell lines U-373 MG and U-87 MG, rat glioma cell line C6, and rat nonfunctioning pituitary adenoma cell line MtT/E. Cell viability was determined by assay with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), and the extent of apoptosis was studied by flow cytometric analysis. Apoptosis was also characterized by morphology using fluorescent microscopy. The role of insulin-like growth factor-I (IGF-I) was studied by assay with MTT, immunohistochemistry, and immunoradiometric assay. After 72-h exposure, a statistically significant loss of viability (P = < 0.0001) was observed at concentrations of 12.5, 25, 50, and 100 microg/ml in U-373 MG cells and U-87 MG cells. EGCG at concentrations of 50 microg/ml and higher significantly reduced the viability of C6 cells. EGCG inhibited viability of MtT/E cells only at a concentration of 100 microg/ml. Quantitative study by flow cytometry demonstrated that lower doses of EGCG (12.5, 25, 50 microg/ml) induced apoptosis in U-373 MG, U-87 MG, and C6 cells; however, only the highest dose (100 microg/ml) induced apoptosis in MtT/E cells. Compared with other cell lines, MtT/E cells showed stronger IGF-I immunoreactivity. Neutralization of IGF-I with an antihuman IGF-I antibody reduced viability of the cell lines. It can be concluded that EGCG has an inhibitory effect on malignant brain tumors, and IGF-I may be involved in the effects of EGCG.

Bilateral thalamic glioma: case report

We report a 63-year-old man who had a rare bilateral thalamic glioma. He complained of difficulty with calculations and had mental deterioration. T1-weighted images revealed bilateral thalamic swelling with homogeneous low signal and no contrast enhancement. The tumour, showing decrease of N-acetylaspartate and the presence of lactate on magnetic resonance spectroscopy, was diagnosed as an astrocytoma by stereotactic biopsy.

Suppression of the tissue factor-dependent coagulation cascade: a contributing factor for the development of intratumoral hemorrhage in glioblastoma

To clarify factors that may contribute to the development of intratumoral hemorrhage, we analyzed the expression of tissue factor (TF), an initiator of the extrinsic coagulation pathway, and of tissue factor pathway inhibitor (TFPI) in glioblastomas with or without massive intratumoral hematoma. Among 196 glioma cases reviewed, there were 13 with macroscopic intratumoral hemorrhage. We focused on the glioblastomas and used immunoblot- and immunohistochemical methods to compare the expression of TF and TFPI in 9 glioblastomas with macroscopic hematoma and 30 glioblastomas without macroscopic hemorrhage. Although TF was expressed in most glioblastomas irrespective of the presence or absence of macroscopic hemorrhage, the staining patterns differed significantly: TF-positive glioma cells were diffusely present in the non-hemorrhage group; in the group with hemorrhage, positive cells, primarily macrophages, were scattered throughout the tissue examined. The expression of TFPI was significantly higher in the group with than in the group without hemorrhage. Our results suggest that local suppression of the TF-dependent coagulation cascade is a contributing factor that permits the occurrence of intratumoral hemorrhage.

Intracranial dural metastasis of mediastinal seminoma--case report

A 24-year-old male presented with a rare intracranial dural metastasis from a mediastinal germ cell tumor infiltrating the superior vena cava, pericardium, ascending aorta, and lung. Routine chest radiography incidentally revealed the abnormal mediastinum, which was partially resected after median sternotomy, followed by radiotherapy. One year after the radiotherapy, magnetic resonance imaging revealed a right parasagittal tumor mimicking a meningioma. Partial tumor removal was performed. Two cycles of chemotherapy with carboplatin and etoposide were then performed, and the residual tumor almost completely disappeared. The histological diagnosis of both the mediastinal and intracranial tumors was pure seminoma. Sections of metastatic tumor revealed several thick fibrous septa and numerous epithelioid granulomas infiltrated by plasma cells, intermingled between the clusters of tumor cells. Follow up of patients apparently in remission from mediastinal seminoma without evidence of advanced or recurrent disease at other sites is recommended.

Randomized comparison of intra-arterial versus intravenous infusion of ACNU for newly diagnosed patients with glioblastoma

This prospective randomized trial was performed to compare the effectiveness of intra-arterial ACNU with intravenous ACNU in newly diagnosed patients with supratentorial glioblastoma. The primary end points were overall survival and progression-free survival. Within 3 weeks after surgery, patients were randomly assigned to receive either intravenous or intra-arterial ACNU (80 mg/m2) once every 6 weeks concomitant with radiotherapy. Intraarterial ACNU was administered for the first 3 courses followed by intravenous administration. Eighty-four patients were enrolled onto this study and among them 82 patients who passed eligibility criteria were analyzed. Patients characteristics were not different significantly between 2 treatment arms. Median survival and progression-free survival time was 59 and 24 weeks, respectively for intra-arterial arm and 56 and 45 weeks, respectively for intravenous arm. There was no significant difference respectively between two treatment arms. Among the prognostic variables including age, Karnofsky performance status, extent of surgery and treatment arm, Cox's proportional hazards model showed that age was the only significant factor for both survival and progression-free survival (P = 0.003 and 0.016, respectively). With regard to toxicity, there was no significant difference between two treatment arms. Leukoencephalopathy was not observed in intra-arterial arm. In conclusion, intra-arterial ACNU when administered by the method in this study does not increase the survival and progression-free survival of newly diagnosed patients with glioblastoma over that afforded by intravenous ACNU.

MRI of a cerebral cryptococcal granuloma

We report a patient with a cerebral cryptococcal granuloma who presented with recent memory disturbance and deteriorating mental status followed by temporary loss of consciousness. To our knowledge, this is the first report of a cerebral cryptococcal granuloma examined by a combination of conventional MRI, fluid-attenuated inversion recovery and diffusion-weighted imaging and in which the surgical specimen was analysed histochemically.

Incidence and clinical features of asymptomatic meningiomas

OBJECT

The increased use of computerized tomography (CT) and magnetic resonance (MR) technology has led to an increase in the detection of asymptomatic meningiomas, although the surgical indication for these tumors remains undetermined. The authors investigated the incidence of asymptomatic meningiomas and their clinical features.

METHODS

An epidemiological survey was conducted of primary intracranial tumors diagnosed in Kumamoto Prefecture between 1989 and 1996. Follow-up neuroradiological imaging and clinical studies for asymptomatic meningiomas were performed. Primary intracranial tumors were diagnosed in 1,563 residents. Of these lesions, 504 (32.2%) were meningiomas, and of these meningiomas 196 (38.9%) were asymptomatic. The incidence of asymptomatic meningiomas was significantly higher in individuals older than 70 years of age. Furthermore, the incidence of asymptomatic meningiomas was significantly higher in female than in male patients. Of the asymptomatic meningiomas in 196 patients, 87 (44.4%) were surgically removed, whereas 109 (55.6%) were treated conservatively. Of these conservatively treated patients, 63 received follow-up care for more than 1 year. In 20 of these 63 cases, the tumors increased in size over the 27.8-month average follow-up period (range 12-87 months), whereas in the other 43 cases, the tumor size did not increase during a 36.6-month average follow-up period (range 12-96 months). There was no significant difference with respect to age, tumor size, and male/female ratio between the patient group in which the tumor size increased and the group in which it did not increase during the follow-up period. Asymptomatic meningiomas that evidenced calcification on CT scans and/or hypointensity on T2-weighted MR images appear to have a slower growth rate.

CONCLUSIONS

Among patients older than age 70 years who underwent operation for asymptomatic meningioma, the neurological morbidity rate was 23.3%; it was 3.5% among younger patients. This indicates that the advisability of surgery in elderly patients with asymptomatic meningiomas must be considered very carefully.

Spinal seeding of anaplastic ependymoma mimicking fungal meningitis. A case report and review of the literature

BACKGROUND

The spinal seeding from brain tumors sometimes mimicks fungal meningitis on examination of cerebrospinal fluid.

METHODS AND RESULTS

A 19-year-old woman gradually developed increased intracranial hypertension. MRI identified a mass in the right parieto-occipital area. It was totally removed and histologically diagnosed as an anaplastic ependymoma. Radiation- and chemotherapy were administered postoperatively. The patient reported low back pain 5 months after the surgical treatment. MRI disclosed neither spinal dissemination nor tumor recurrence at the primary site. Lumbar puncture was performed and the cerebrospinal fluid (CSF) was found to have an extremely low glucose level (5 mg/dl); no tumor cells were identified. Blood samples were obtained and a relative increase of WBC and CRP was noted. A slight degree of inflammation and low-grade fever were recorded. A tentative diagnosis of fungal meningitis was made and anti-fungal therapy was administered transventricularly and transvenously. However, her neurological condition continued to deteriorate gradually. Sequential CSF studies showed that the glucose level remained extremely low, it even decreased to 0 mg/dl Eight months after the surgical treatment, MRI with Gd-DTPA revealed marked subarachnoid enhancement in both intracranial and spinal areas. An open biopsy was performed and a histological diagnosis of intracranial and spinal seeding of the anaplastic ependymoma was returned.

CONCLUSIONS

We report a patient with intracranial and spinal seeding of an anaplastic ependymoma that mimicked fungal meningitis. We discuss the difficulty of obtaining a differential diagnosis in this case and describe the mechanism of the decreased CSF glucose level.

Long-term follow-up study of patients with cavernous sinus aneurysm treated by proximal occlusion

Proximal occlusion of the internal carotid artery (ICA) is still the treatment of choice for a large cavernous sinus aneurysm. Endovascular occlusion or trapping of the ICA with or without an extracranial-intracranial bypass is sometimes performed. We analyzed the results of the long-term follow up of 11 patients with a giant or large cavernous sinus aneurysm treated by only proximal occlusion between 1975 and 1989. Proximal occlusion of the carotid artery was performed by Selverstone clamping. The follow-up period ranged from 6 to 21 years (mean 13.9 years). Eight of the 11 patients showed improvement of cranial nerves paresis or headache, and four became asymptomatic. None of the original aneurysms ruptured. The final outcomes were nine good recovery, one moderately disabled, and one severely disabled by the Glasgow Outcome Scale. The causes of morbidity were early ischemia and subarachnoid hemorrhage from a newly formed aneurysm. Late complications included ischemia in two patients, and new formation and enlargement of aneurysms at a site other than the original aneurysm in two patients, 13 and 17 years later. Therapeutic carotid artery occlusion requires strict test ICA occlusion. In addition, long-term follow up by periodical cerebral angiography using magnetic resonance, computed tomography, or digital subtraction angiography is necessary, and postoperative medical treatment is important to reduce the risk of late complications.

Highly efficient electro-gene therapy of solid tumor by using an expression plasmid for the herpes simplex virus thymidine kinase gene

We report successful electro-gene therapy (EGT) by using plasmid DNA for tumor-bearing mice. Subcutaneously inoculated CT26 tumor was subjected to EGT, which consists of intratumoral injection of a naked plasmid encoding a marker gene or a therapeutic gene, followed by in vivo electroporation (EP). When this treatment modality is carried out with the plasmid DNA for the green fluorescent protein gene, followed by in vivo EP with the optimized pulse parameters, numerous intensely bright green fluorescent signals appeared within the tumor. EGT, by using the "A" fragment of the diphtheria toxin gene significantly inhibited the growth of tumors, by about 30%, on the flank of mice. With the herpes simplex virus thymidine kinase gene, followed by systemic injection of ganciclovir, EGT was far more effective in retarding tumor growth, varying between 50% and 90%, compared with the other controls. Based on these results, it appears that EGT can be used successfully for treating murine solid tumors.

MRI demonstration of intracerebral cryptococcal granuloma

We report an intracerebral cryptococcal granuloma in a patient who presented with recent memory disturbance and deteriorating mental status followed by temporary loss of consciousness. To our knowledge, this is the first reported case of an intracerebral cryptococcal granuloma examined by a combination of conventional MRI, fluid-attenuated inversion-recovery and diffusion-weighted imaging and in which the surgical specimen was analysed histochemically.

Natural history of elderly patients with asymptomatic meningiomas

OBJECTIVE

For the treatment of elderly patients with asymptomatic meningiomas, it is important to determine their natural history. Based on results of follow up examinations, the natural history of such patients was clarified and prognostic factors concerning the potential of tumour growth in the aged were identified.

METHODS

The clinical records and imaging studies of 40 elderly (over 70 years) patients with asymptomatic meningiomas were analysed. The patients were followed up with repeated imaging studies, and changes in tumour size, clinical signs, and outcomes were evaluated.

RESULTS

There were 32 women and eight men with a mean age of 76.1 years. The mean follow up period was 38.4 months, ranging from 6 to 97 months. Six patients died during the follow up period from disorders other than the tumours, and one patient died as a result of the tumour. Twenty six patients (mean follow up period 41.8 months, range 10-97 months) showed no tumour growth. Fourteen patients showed tumour growth (mean follow up period 32.1 months, range 6-88 months). Five (four men and one woman) of these patients became symptomatic. Based on imaging analysis (1) calcification of the tumour was associated with no tumour growth (p=0.036), and (2) the tumour size at the initial diagnosis was related to subsequent tumour growth (p=0.016). Other possible factors related to tumour growth included sex and hyperintensity on MRI T2 weighted images.

CONCLUSION

In elderly patients with asymptomatic meningiomas, careful clinical follow up with imaging studies is important. The imaging features mentioned may contribute to prediction of tumour growth.

Reporter/Functional gene transfer in rat brain

Of the many methods and techniques for in vivo gene transfer, some have already been used in clinical trials. In most cases, genes are transferred into tissues using the infectivity of viral particles. However, viral systems have some known drawbacks (1,2). If an efficient and specific transfer method could be developed, naked plasmid DNA would be an ideal system for gene transfer. Plasmid-mediated methods would be economical and easy. Also, the transfer procedure could be easily repeated, as naked plasmid DNA has little antigenicity for the host (3,4).

Association of venous angioma and atypical meningioma--case report

A 67-year-old male presented with an atypical meningioma arising from the right tentorium associated with a venous angioma in the left cerebellar hemisphere. The venous angioma was detected incidentally during examinations for the brain tumor. The brain tumor was removed completely and the venous angioma followed conservatively. Venous angiomas associated with brain tumors should be followed conservatively, as the clinical significance and surgical indications are unclear.