Motohiko Maruno

Induction of aquaporin-4 water channel mRNA after focal cerebral ischemia in rat.

Aquaporin-4 (AQP4) is a member of a water-selective channel aquaporin-family and mainly expressed in the several structures of the brain and in the collecting duct of the kidney. Here we show its functional involvement in the water homeostasis of the ischemic brain. The expression of AQP4-mRNA is increased in the peri-infarcted cortex during the observation period ( approximately 7 days) after MCA-occlusion, maximally on day 3. The change corresponds to the generation and resolution of brain edema monitored by MRI. The signals for the mRNA are predominantly observed in glial cells in the molecular and outer granular layer of the peri-infarcted cortex. These results indicate that AQP4 plays a role in post-ischemic edema formation.

Fiber-tracking does not accurately estimate size of fiber bundle in pathological condition : initial neurosurgical experience using neuronavigation and subcortical white matter stimulation

The fiber-tracking method enables in vivo visualization of the white matter tracts of the brain using a diffusion tensor MR imaging technique. While this method represents a promising tool in the field of neurosurgery, especially when confronted with brain tumors in eloquent areas, its reliability remains unknown. We present here our preliminary validation of tractography in human subjects harboring brain tumors by comparing the results produced by neuronavigation and electrical white matter stimulation in two patients with gliomas in the eloquent area. Although we were able to visualize the pyramidal tract with the fiber-tracking technique, the images failed to present the actual size of the fiber bundles. Here we discuss the advantages and limitations of fiber-tracking in the field of neurosurgery.

Phase II clinical trial of Wilms tumor 1 peptide vaccination for patients with recurrent glioblastoma multiforme

OBJECT The object of this study was to investigate the safety and clinical responses of immunotherapy targeting the WT1 (Wilms tumor 1) gene product in patients with recurrent glioblastoma multiforme (GBM). METHODS Twenty-one patients with WT1/HLA-A*2402-positive recurrent GBM were included in a Phase II clinical study of WT1 vaccine therapy. In all patients, the tumors were resistant to standard therapy. Patients received intra-dermal injections of an HLA-A*2402-restricted, modified 9-mer WT1 peptide every week for 12 weeks. Tumor size, which was obtained by measuring the contrast-enhanced area on magnetic resonance images, was determined every 4 weeks. The responses were analyzed according to Response Evaluation Criteria in Solid Tumors (RECIST) 12 weeks after the initial vaccination. Patients who achieved an effective response continued to be vaccinated until tumor progression occurred. Progression-free survival and overall survival after initial WT1 treatment were estimated. RESULTS The protocol was well tolerated; only local erythema occurred at the WT1 vaccine injection site. The clinical responses were as follows: partial response in 2 patients, stable disease in 10 patients, and progressive disease in 9 patients. No patient had a complete response. The overall response rate (cases with complete or partial response) was 9.5%, and the disease control rate (cases with complete or partial response as well as those in which disease was stable) was 57.1%. The median progression-free survival (PFS) period was 20.0 weeks, and the 6-month (26-week) PFS rate was 33.3%. CONCLUSIONS Although a small uncontrolled nonrandomized trial, this study showed that WT1 vaccine therapy for patients with WT1/HLA-A*2402-positive recurrent GBM was safe and produced a clinical response. Based on these results, further clinical studies of WT1 vaccine therapy in patients with malignant glioma are warranted.

Frequency-dependent spatial distribution of human somatosensory evoked neuromagnetic fields

Using synthetic aperture magnetometry (SAM), we examined the spatial distribution of frequency changes in magnetoencephalography signal rhythms on individual magnetic resonance images following somatosensory stimulation. SAM is a novel statistical spatial filtering method that uses an adaptive beamformer. Electrical stimulation of the right median nerve demonstrated high-frequency event-related synchronization (ERS) in the 50-200-Hz range, consistently localized in the contralateral primary sensorimotor area in all subjects (n=7). Event-related desynchronization (ERD) was demonstrated in the 8-13, 13-25 and 25-50-Hz ranges bilaterally in the area surrounding the central sulcus. The differences in the spatial distribution as well as the frequency bands between ERS and ERD suggest that ERS and ERD reflect the responses of different cell assemblies rather than a frequency shift of the same cell assembly.

Cellular dynamics of macrophages and microglial cells in reaction to stab wounds in rat cerebral cortex.

Summary To examine the cellular dynamics of macrophages and microglial cells in response to cerebral injury, we studied the brain adjacent to cortical stab wounds in young adult rats. Brains were obtained 30 min after intravenous infusion of bromodeoxyuridine (BrdU) on one day (day 1) to 28 days (day 28) after wounding. Brain sections were double-labelled immunohistochemically for monocyte/macrophage antigen ED1 and for BrdU. ED1-positive (ED1+) cells were classified morphologically into two groups, ED1+L and ED1+S cells, representing macrophages and microglial cells, respectively. ED1+L cells appeared on day 1 after wounding and rapidly increased in number to reach a maximum on day 3, but quickly disappeared by day 5. ED1+S cells also appeared on day 1, but the increase in number was slower, reaching a maximum only on day 7. ED1+L cells were all negative for BrdU, but some ED1+S cells were stained for BrdU, evidence of proliferation. The present investigation demonstrated different cellular dynamics for macrophages and microglial cells responding to a stab wound, and also indicated differing sources for the two cell type. It may be possible to prevent the accumulation of these cells which are harmful to the brain in reducing the damage suffered.

Genetic analysis of human glioblastomas using a genomic microarray system.

Genomic microarray systems can simultaneously provide substantial genetic and chromosomal information in a relatively short time. We have analyzed genomic DNA from frozen sections of 30 cases of primary glioblastomas by GenoSensor Array 300 in order to characterize gene amplifications, gene deletions, and chromosomal information in the whole genome. Genes that were frequently amplified includedPFC2/CYLN2 (63.3%),EGFR (53.3%),IL6 (53.3%),ABCB1 (MDR1) (36.7%), andPDGFRA (26.7%). Genes that were frequently deleted includedFGFR2 (66.7%),MTAP (60.0%),DMBT1 (56.7%),CDKN2A (p16)/MTAP (50.0%),PIK3CA (43.3%), andEGR2 (43.3%), but deletion ofRB1 orTP53 was rarely detected. Chromosomal gains were observed frequently for 7q (33.3%), 7p (20.0%), and 17q (13.3%). Loss of the 10q was frequently detected in 13 of 30 cases (46.7%). Loss of the entire chromosome 10 was seen in 9 of 30 cases (30.0%), and was often accompanied byEGFR amplification (7 cases, 77.8%). The GenoSensor Array 300 proved to be useful for identification of genome-wide molecular changes in glioblastomas. The obtained microarray profile can also yield valuable insight into the molecular events underlying carcinogenesis of brain tumors and may provide clues about clinical correlations, including response to treatment.

Expression of thrombomodulin in astrocytomas of various malignancy and in gliotic and normal brains

SummaryA total of 22 surgical specimens, 16 astrocytomas with various malignancy, 3 brains adjacent to tumor and 3 brains with non-neoplastic lesion, was investigated immunohistochemically for the expression of thrombomodulin (TM). This membrane protein is localized on the vascular endothelium of nearly every human tissue and plays a crucial role in the maintenance of antithrombotic property of the endothelial cells. Although the normal cerebral vessels were negative for TM, the tumor vessels were positive for TM. The increased expression of TM was, however, demonstrated not only in glioblastomas but also in low-grade astrocytomas. Furthermore, the vessels in the brains adjacent to tumor and gliotic brains were also positive for TM. Those observations suggested that the tendency of intratumoral bleeding, which is rather characteristic of glioblastomas, is not simply explained by the altered expression of vascular endothelial TM. In two cases of glioblastoma, not only the blood vessels but also the tumor cells were positive. Considering the mitogenic activity of thrombin, a ligand for TM, the increased expression of TM might be related to the tumor neovascularization and also the tumor growth.

Overexpressed Skp2 within 5p amplification detected by array‐based comparative genomic hybridization is associated with poor prognosis of glioblastomas

To better understand the pathogenesis of glioblastoma multiforme (GBM) and to increase the accuracy of predicting outcomes for patients with this disease, we performed genome‐wide screening for DNA copy‐number aberrations in 22 glioma‐derived cell lines using a custom‐made comparative genomic hybridization‐array. Copy‐number gains were frequently detected at 3q, 7p, 7q, 20q, Xp and Xq, and losses at 4q, 9p, 10p, 10q, 11q, 13q, 14q, 18q, and 22q. Among several non‐random chromosomal aberrations, the gain/amplification of DNA at 5p, which has never been reported before in GBM, was detected with a relatively high ratio (log2 ratio = 0.41–1.19) in four cell lines. Amplification and subsequent overexpression of SKP2, a possible target of amplification within 5p, were detected in four of the 22 cell lines. We also investigated the expression of the gene product in primary GBM by immunohistochemistry, which revealed increased levels of Skp2 in 11 of the 35 tumors examined (31.4%). Heightened expression of Skp2 was associated with shorter overall survival (P = 0.001, logrank test), especially in patients younger than 65 years. These results suggest that overexpression of Skp2 through gene amplification may contribute to the pathogenesis of GBM, and that overabundance of the protein might be a useful prognostic tool in patients with this disease.(Cancer Sci 2005; 96: 676 – 683)

Stereotactic radiofrequency ablation for sessile hypothalamic hamartoma with an image fusion technique

Summary¶Background. Radiosurgery has been advocated as a primary treatment for hypothalamic hamartoma (HH), but it has a risk of damaging the surrounding structures and does not have an immediate effect for refractory epilepsy, endocrinological and mental disorders.Method. We report on a 13-year-old boy with a large and sessile HH who presented with intractable seizures, precocious puberty and aggressiveness. Stereotactic radiofrequency ablation (SRA) combined with an image fusion technique was performed to make a maximum ablative lesion within the HH via multiple trajectories.Findings. After surgery, we observed rapid cessation of the gelastic seizures and aggressiveness. The ophthalmological function did not get worse, and the hypothalamopituitary function improved.Interpretation. SRA in combination with an image fusion technique is a viable alternative treatment for HH, because it provides precise preoperative simulation and immediate improvement of symptoms can be obtained.

Cerebral motor control in patients with gliomas around the central sulcus studied with spatially filtered magnetoencephalography

Objective: Application of spatially filtered magnetoencephalography (MEG) to investigate changes in the mechanism of cerebral motor control in patients with tumours around the central sulcus. Methods: MEG records were made during a repetitive hand grasping task in six patients with gliomas around the central sulcus and in four control subjects. Power decreases in the α (8–13 Hz), β (13–30 Hz), and low γ bands (30–50 Hz) during the motor tasks (event related desynchronisation, ERD) were analysed statistically with synthetic aperture magnetometry. The tomography of ERD was superimposed on the individual’s magnetic resonance image. Results: β ERD was consistently localised to the contralateral primary sensorimotor cortex (MI/SI) in control subjects, whereas the α and low γ ERD showed considerable intersubject variability. β ERD in patients during non-affected side hand movement was also localised to the contralateral MI/SI, but exclusively to the ipsilateral hemisphere during affected side hand movement. Conclusions: The altered pattern of ERD in the patient group during affected side hand movement suggests recruitment of diverse motor areas, especially the ipsilateral MI/SI, which may be required for the effective movement of the affected hand.