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 The hook can be extended or withdrawn freely by pushing or pulling the hilt.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 Then the inner hook was withdrawn into the cannula and the entire device was removed.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.