We have shown the protection of human central nervous system (CNS) cultures by zinc (Zn) or cadmium (Cd)-pre-induced metallothionein (MT) synthesis from radiation-induced cytotoxicity (lactate dehydrogenase (LDH) release and neuronal dendritic injury). The present study is to further define the types of cell death induced by different dose levels of radiation and investigate the effect of MT induction (by Zn or Cd) on radiation-induced apoptosis in primary human CNS and astrocyte cultures. Apoptosis was detected by fragmented DNA electrophoresis, TUNEL technique, and propidium iodide staining. Expression of MT protein was examined by immunofluorescent staining. Results showed that exposure of primary human CNS cultures to 15 and 30Gy γ-radiation predominantly induced apoptotic cell death, while exposure to 60Gy γ-radiation predominantly induced necrotic cell death. Normal primary human CNS cultures showed weak MT staining, while primary human CNS cultures exposed to Zn or Cd showed intense MT staining. The induced apoptotic cell death by exposure to 30Gy γ-radiation increased to a maximum level at 12 and 24h, and was reduced significantly by Zn or Cd pre-induced MT. Using primary human astrocytes, the induction of MT protein by Zn or Cd was further confirmed. The enhanced MT expression also afforded a significant protection from 30Gy γ-ray-induced apoptosis in the primary human astrocytes. These results suggest that MT protected human CNS cells from apoptosis following ionizing radiation, probably through its antioxidant property.

HIV-1-associated dementia remains a common subacute to chronic central nervous system degeneration in adult and pediatric HIV-1 infected populations. A number of viral and host factors have been implicated including the HIV-1 120 kDa envelope glycoprotein (gp120). In human post-mortem studies using confocal scanning laser microscopy for microtubule-associated protein 2 and synaptophysin, neuronal dendritic pathology correlated with dementia. In the present study, primary human CNS cultures exposed to HIV-1 gp120 at 4 weeks in vitro suffered gliosis and dendritic damage analogous to that described in association with HIV-1-associated dementia.

Background: The ontogeny and maturity of neurons and oligodendroglia-like cells (OLC) found in dysembryoplastic neuroepithelial tumors (DNT) remains controversial. A developmental origin has been proposed based on the close association to cortical dysplasia and the benign microscopic and clinical course. Our goal was to characterize the expression of nestin, a neuroepithelial precursor/stem cell antigen in DNT, along with other pathological and clinical features of this entity. Methods: The clinical and operative features of 13 surgical specimens meeting the histological criteria for DNT were reviewed. Nestin, microtubule-associated protein 2 (MAP2), neurofilament (NF) and glial fibrillary acidic protein (GFAP) were examined by immunohistochemistry and confocal scanning laser microscopy. Results: Select neuronal cells in all cases demonstrated strong MAP2 immunoreactivity. Nestin-positive cells of neuronal morphology were found in 6 cases. OLC demonstrated frequent selective staining for MAP2, GFAP and nestin. Confocal microscopy demonstrated numerous examples of cells co-expressing nestin and MAP2. Conclusions: Our study suggests that OLCs represent a united population of immature neuronal (nestin + MAP2) and glial (GFAP) phenotypes. Larger, morphologically recognizable neurons also showed occasional co-expression of nestin and MAP2, suggesting a degree of dysmaturity in common with their OLC counterparts. The apparent mixed lineage of OLCs lends support to theories suggesting that DNTs arise from pluripotent neuroepithelial cells.

BACKGROUND:Dural cavernous angiomas are uncommon benign vascular malformations which may present intraoperative difficulties in hemostasis when the diagnosis is not suspected preoperatively. Preoperative diagnosis can be difficult when angiomas show atypical features and share imaging characteristics with other entities.METHODS:A patient presented with a radiographically aggressive lesion, subsequently identified as a dural cavernous angioma. The lesion is reviewed and its clinical, radiographic, and pathological features are compared with other vascular malformations.CASE REPORT:A 40-year-old man presented with new onset seizures and an enhancing lesion infiltrating the floor of the right middle cranial fossa. Due to its aggressive radiographic appearance, initial considerations included chondrosarcoma, meningioma or metastasis. Pathological examination, however, revealed the lesion to be a cavernous angioma of dura.CONCLUSION:This uncommon lesion may present a diagnostic challenge with significant intraoperative implications. T2 sequence hyperintensity in a relevant lesion should raise suspicion of an hemangioma. It is important to be aware of this entity and its potential to mimic other entities on radiographic grounds.

Primary dissociated human fetal forebrain cultures were grown in defined serum-free conditions. At 4 weeks in vitro the cultures contained abundant morphologically well differentiated neurons with complex dendritic arbors. Astrocytic proliferation was negligible without the use of antimitotic agents. Confocal scanning laser microscopy (CSLM) and electron microscopy confirmed the presence of a dense neuropil, numerous cell–cell contacts and synapses. Neurons expressed a variety of proteins including growth associated protein-43 (GAP43), microtubule associated protein-2ab (MAP), class-III beta tubulin (C3BT), neurofilaments (NF), synaptophysin (SYN), parvalbumin (PA) and calbindin (CB). The cultures have proven to be reliable and simple to initiate and maintain for many weeks without passaging. They are useful in investigations of dendritic growth and injury of primary human CNS neurons.

OBJECT:It is recognized that cortical dysplasia (CD) is associated with an increased incidence of glioneuronal neoplasms. Among hypothetical considerations, there is the possibility that CD and other neuronal migration abnormalities harbor dysmature cells with the potential to give rise to glioneuronal neoplasms. Such cells, if present, would be reasonably expected to display immature features. The goal of the present study was to characterize the expression of nestin, a neuroepithelial precursor/stem cell antigen, in CD, along with other pathological and clinical features of this entity.METHODS:Clinical and surgical features of 10 recent cases meeting the histological criteria for CD were reviewed. Expressions of nestin, MAP2, neurofilament, and glial fibrillary acidic protein (GFAP) were assessed using immunohistochemical analysis and confocal scanning laser microscopy. Immunoreactivity for both glial and neuronal antigens as well as nestin was found in a select group of cells within regions of CD. Immunohistochemical and confocal microscopic findings demonstrated that these cells with neuronal or ambiguous features are a mixed population, some of which are dysmature neurons (positive for nestin and MAP2), whereas others are astrocytic (positive for nestin and GFAP).CONCLUSIONS:Further insight into the nature of nestin-positive neurons may shed light on the cause and pathogenesis of the associated glioneuronal tumors and the accompanying chronic seizures.

PURPOSE There have been extensive studies on the regulation of metallothionein (MT) synthesis, and its biological role in liver and kidney. Although there are few reports on brain MT, there is a growing interest in the role of MT in brain. There have been no publications to date on MT synthesis in the human central nervous system (CNS) following exposure to ionizing radiation. In the present study, primary human CNS cultures were used to examine the effect of ionizing radiation on MT mRNA and protein synthesis. In the same cultures, the neuroprotective effects of zinc (Zn) and cadmium (Cd)-induced MT synthesis from high-dose radiation were also examined. MATERIALS AND METHODS Primary, serum-free, human CNS cultures were exposed to 30 or 60 Gy gamma-rays. The total MT protein was then measured by a Cd-heme assay, and mRNA for MT-II and MT-III was detected by reverse transcription polymerase chain reaction (RT-PCR). Cytotoxicity was measured by LDH release and apoptotic cell death by DNA fragmentation analysis. Sublethal neuroglial injury was assessed morphologically using specific astrocytic (glial fibrillary acidic protein--GFAP) and neuronal (microtubule-associated protein 2--MAP2) immunohistochemical markers. RESULTS The total MT protein content was increased 12h after exposure to 30Gy. The increase in MT content in response to 60Gy was not statistically significant. MT-II mRNA levels increased at 3 and 6h after exposure to 30Gy gamma-rays, with a maximum expression at 12-24 h. MT-III mRNA was not significantly affected. Exposure to 60 Gy, but not 30 Gy, caused a marked increase in LDH release. Cells exposed to 30 Gy or less showed some apoptotic cell death by DNA fragmentation analysis, while exposure to 60 Gy resulted in a DNA smear confirmed by LDH assays. Preinduction of MT by 5 microM Cd or 100 microM Zn resulted in a significant reduction in radiation-induced LDH release. Morphological evaluations revealed that Cd or Zn preincubation led to relative preservation of MAP2 staining and GFAP. CONCLUSION Both MT protein and MT-II mRNA can be induced in human CNS cells by ionizing radiation. Furthermore, induction of MT synthesis with Zn and Cd can protect human CNS cells from radiation-induced cytocidal and sublethal injuries. Both findings have implications in the development of strategies to protect human CNS tissue from damage during radiotherapy.