Hiroshi K. Inoue

Gamma knife for glioma: Selection factors and survival

PURPOSE To determine factors associated with survival differences in patients treated with radiosurgery for glioma. METHODS AND MATERIALS We analyzed 189 patients treated with Gamma Knife radiosurgery for primary or recurrent glioma World Health Organization (WHO) Grades 1-4. RESULTS CONCLUSION The median minimum tumor dose was 16 Gy (8-30 Gy) and the median tumor volume was 5.9 cc (1.3-52 cc). Brachytherapy selection criteria were satisfied in 65% of patients. Median follow-up of all surviving patients was 65 weeks after radiosurgery. For primary glioblastoma patients, median survival from the date of pathologic diagnosis was 86 weeks if brachytherapy criteria were satisfied and 40 weeks if they were not (p = 0.01), indicating that selection factors strongly influence survival. Multivariate analysis showed that increased survival was associated with five variables: lower pathologic grade, younger age, increased Karnofsky performance status (KPS), smaller tumor volume, and unifocal tumor. Survival was not found to be significantly related to radiosurgical technical parameters (dose, number of isocenters, prescription isodose percent, inhomogeneity) or extent of preradiosurgery surgery. We developed a hazard ratio model that is independent of the technical details of radiosurgery and applied it to reported radiosurgery and brachytherapy series, demonstrating a significant correlation between survival and hazard ratio. CONCLUSIONS Survival after radiosurgery for glioma is strongly related to five selection variables. Much of the variation in survival reported in previous series can be attributed to differences in distributions of these variables. These variables should be considered in selecting patients for radiosurgery and in the design of future studies.

Identification of a synaptic vesicle-specific 38,000-dalton protein by monoclonal antibodies

Synaptic vesicles were purified from the guinea pig cerebrum by sucrose density gradient centrifugation, and monoclonal antibodies (MAbs) were produced against this vesicle fraction. Seven MAbs (171B5, 171E8, 174D12, 174H11, 177A2, 177H11 and 178D4) recognized a novel acidic protein of about 38,000 daltons which was specific to synaptic vesicles. In immunofluorescence microscopy, the staining pattern of these MAbs corresponded to the distribution of the synapses in the guinea pig central nervous system. These MAbs appeared to stain all synaptic regions, irrespective of their synaptic function or type of neurotransmitters. MAb 171B5 and 174H11 stained the rat, rabbit and bovine synapses similarly to the guinea pig. Two other MAbs (171E8 and 177H11) stained other mammals weakly but the remaining 3 MAbs reacted only with the guinea pig. In immunoelectron microscopy of both the cerebellar tissue and isolated vesicle fraction, these MAbs selectively labeled the synaptic vesicles but not other structures. Immunoblot analysis was performed on electrophoretically separated proteins in vesicle fraction and brain homogenate. All of 7 MAbs reacted with a band at a molecular weight of about 38,000 from the guinea pig. Isoelectric focussing disclosed that this protein was acidic (pI 4.5-5).

Pituitary Adenomas Treated by Microsurgery with or without Gamma Knife Surgery: Experience in 122 Cases

The clinical outcome of 122 patients with pituitary adenomas treated by microsurgery and/or Gamma Knife radiosurgery (GKRS) was analyzed to evaluate patient selection criteria and the role of GKRS. Sixty-six resections were performed in 59 patients. All tumors were macroadenomas, except for 5 ACTH-producing adenomas. Twenty-four of the 31 hypersecreting adenomas showed normal serum hormone values after treatment. Postoperative complications were rhinorrhea, cranial nerve palsies, and a small thalamic infarct. GKRS was performed on 18 of the operated patients because of residual tumors, mostly in the cavernous sinus. Thirty-five of the 63 patients treated by GKRS were followed for more than 2 years. All adenomas except 2 were stable or had decreased in size. Eleven of 17 functioning adenomas showed normal serum hormone values after treatment. It is concluded that tumors that compress the optic pathway should be removed and that residual tumors in the cavernous sinus are good indications for radiosurgery.

Four synaptic vesicle-specific proteins: identification by monoclonal antibodies and distribution in the nervous tissue and the adrenal medulla

Synaptic vesicles from the guinea-pig cerebrum were isolated and administered to mice for the production of monoclonal antibodies (MAb). Four vesicle-associated proteins in the guinea-pig nervous tissue were specifically and differentially recognized by MAbs thus obtained. These proteins had molecular weights of 30,000, 36,000, 38,000 and 65,000 Da and were named SVPs (synaptic vesicle proteins) 30, 36, 38 and 65, respectively. Immunohistochemistry demonstrated that all SVPs were localized in the synaptic regions throughout the central nervous system and in the adrenal medulla. Nerve terminals in skeletal muscle, smooth muscle and sympathetic ganglion contained SVPs 36 and 38. Immunoelectron microscopy of the cerebellar cortex confirmed the localization of SVPs in the synaptic vesicles and the adjacent membranes of the presynaptic nerve terminals. Fractionation of the cerebral tissue and treatment with various agents showed that SVPs were localized in the synaptic vesicles and the synaptic plasma membrane and that SVPs were integrated within the membrane and liberated only after solubilization of the membrane.

Localization of a developmentally regulated neuron-specific protein S54 in dendrites as revealed by immunoelectron microscopy

We sought to determine the ultrastructural localization of the developmentally regulated neuron-specific protein S54 in the chicken cerebellar cortex and optic tectum. The brains were fixed by perfusion with paraformaldehyde and glutaraldehyde. Frozen sections were immunocytochemically labeled with a monoclonal antibody to S54 protein. The immunoreactivity for S54 protein was localized in dendrites. No immunoreactivity for S54 protein was detected in axons and their presynaptic terminals.

An unusual variant of ependymoma with extensive tumor cell vacuolization

Abstract We report a case of ependymoma with unusual vacuolar features arising in the left occipital lobe of a 2-year-old child. The tumor was composed of cells with single or multiple cytoplasmic vacuoles and clear cells. Some cells showed a signet ring-like configuration. Clear cells were compactly arranged and showed an oligodendroglioma-like appearance. In addition, there were cellular ependymoma-like areas including perivascular pseudorosettes. On immunohistochemistry, glial fibrillary acidic protein and vimentin were mainly detected in cytoplasmic processes, and epithelial membrane antigen (EMA) staining showed granular and small vesicular reactivity. Ultrastructural investigation demonstrated intercellular microrosettes with or without cilia and long zonula adherens-type junctions that are typical of ependymoma. Furthermore, many intracytoplasmic lumina (ICL) were observed. Some ICL had microvilli and some did not. The latter varied in size, and may have fused with each other to develop giant ICL which could correspond to the signet ring-like configuration. Small ICL without microvilli had an appearance similar to that of distended endoplasmic reticula. Serial semithin and ultrathin sections revealed that EMA-positive structures were consistent with ICL containing microvilli and intercellular microrosettes. To determine the presence of unusual vacuolated ependymoma, electron microscopical examination was required. However, light microscopy was useful for detecting EMA-positive microvesicular and granular structures.

Three-dimensional observations on microvascular growth in rat glioma using a vascular casting method

SummaryThe microvascular growth of ethylni-trosourea-induced rat glioma was observed using vascular casting and scanning electron microscopy (SEM). Light microscopy showed central necrosis and marginal invasive tumor cell growth with increased vascularity, and suggested that adopted pre-existing circulation was dominant in the inoculated brain tumors. In SEM, numerous buds or nodular protrusions and a few large and tortuous vessels along the tumor margin were seen at the early stage. In the intermediate stage, microaneurysms, buds with septum formation and anastomotic arches appeared, and these tumor vessels became more tortuous and larger, and extended as the tumor grew. Several “potato-shaped” huge vessels and linear nodular large vessels also appeared. In the late stage, glomeruli appeared and potato-shaped huge vessels increased in number. The neovascularization and microvascular growth of the tumors was characterized by three patterns: (a) growth of the parent vessels forming buds, (b) vascular growth in a meshwork formation producing glomeruli, and (c) vascular enlargement without a definite pattern creating potato-shaped huge vessels. The tumor vessels gradually lost their natural three-dimensional structure.

Stimulation of L‐type Ca2+ channel in growth cones activates two independent signaling pathways

Although growth cones respond to various modulators of neurite outgrowth, such as neurotrophins, neurotransmitters, and cell adhesion molecules, the signal‐transducing mechanisms for these modulators in growth cones are unclear. Since recent studies have suggested that the signals of these modulators are mediated by Ca2+ influx through L‐type voltage‐sensitive Ca2+ channels (VSCCs) in the growth cone, we examined L‐type VSCC‐dependent signaling pathways, using isolated growth cones (IGCs) from developing rat forebrains. Binding assays revealed that L‐type VSCC is enriched in growth cone membrane and gradually decreased in amount developmentally, while N‐type VSCC has the opposite tendency. In intact IGCs, Bay K 8644 (BK, an L‐type agonist) induced much more rapid elevation of [Ca2+]i than that in adult synaptosomes. Ca2+‐dependent phosphorylation of GAP‐43 and MARCKS protein by protein kinase C (PKC) was enhanced in the IGC by BK, resulting in the release of these proteins from the membrane, which is consistent with our recent report. In addition, the Ca2+‐dependent degradation of brain spectrin (fodrin) by calpain was also enhanced by BK or GABA, consequently inducing the release of α‐actinin from the membrane skeleton of the growth cones. The activities of PKC and calpain were not inhibited by inhibitors of the other, indicating that these reactions occur independently. Our results suggest that Ca2+ influx through L‐type VSCCs activates two distinct signaling branches, probably in the different domains of the growth cone, i.e., Ca2+‐dependent phosphorylation of GAP‐43 and MARCKS protein, and Ca2+‐dependent degradation of brain spectrin and the release of α‐actinin by calpain. J. Neurosci. Res. 51:682–696, 1998.

Gamma Thalamotomy for Parkinsonian and Other Kinds of Tremor

On the basis of our experiences with selective ventralis intermedius thalamotomy with microrecording, certain cases of tremor with Parkinsons disease (PD, six cases), intentional tremor (one case) and essential tremor (one case) were treated by Gamma Knife. In all cases, 140-150 Gy were irradiated using 4-mm collimators. Three different strategies were used. (1) Gamma thalamotomy as the primary surgical treatment. (2) As a secondary treatment, irradiation of the symmetric point of the contralateral selective thalamotomy. (3) Extension of the previous thalamotomy. For the first three cases (all PD), a special plug pattern (100 plugs) was used, but was not employed for the later cases. No acute untoward effects were noted, and overall there appeared to be a reduction in tremor. The time course of tremor reduction varied from case to case, from about 5-6 months to 1 year.

Diagnosis of germinal neoplasm in the thalamus and basal ganglia

Germinal neoplasms originating in the thalamus and basal ganglia were histologically verified by stereotactic biopsies in five cases and by other methods in three cases. Immunoperoxidase staining was performed on the tumors using antibodies against human chorionic gonadotropin and placental alkaline phosphatase. The presence of human chorionic gonadotropin was demonstrated in one germinoma and two mixed tumors, but not in three germinomas. Placental alkaline phosphatase was demonstrated to be present in four germinomas and one mixed tumor. Stereotactic biopsy specimens can be studied immunohistochemically, and the placental isoenzyme of alkaline phosphatase appears to be a new tumor marker for germinoma.