No abstract available.
Neuroepithelial Cells* ; Regeneration*

Teratomas are embryonal neoplasms that show characteristics from all three germ layers(ectoderm, endoderm, and mesoderm). These tumors are frequently present in infancy and childhood. Teratomas are classified into three groups : mature teratoma, immature teratoma, and teratomas with malignant elements. The histopathologic findings of immature teratoma is primitive neuroepithelial cells compounding pseudostratified tubular formations. The pure immature teratoma accounts for fewer than 1% of all germ cell malignancies. The immature teratomas in nasal cavity are very rare tumor. These tumors are often presented as neonatal respiratory distress, nasal obstruction and epistaxis. We report a case of histologically confirmed immature teratoma in nasal cavity in 48 years old man with review of the literature.
Endoderm ; Epistaxis ; Germ Cells ; Humans ; Middle Aged ; Nasal Cavity* ; Nasal Obstruction ; Neoplasms, Germ Cell and Embryonal ; Neuroepithelial Cells ; Teratoma*

Eph receptors and their ligands, ephrins, are abundantly expressed in neuroepithelial cells of the early embryonic brain. Overstimulation of Eph signaling in vivo increases apoptotic cell death of neuroepithelial cells, whereas null mutation of the Eph gene leads to the development of a larger brain during embryogenesis. Thus, it appears that Eph-ephrin signaling plays a role in regulating apoptotic cell death of neuroepithelial cells, thereby influencing brain size during embryonic development. Interestingly, Eph-ephrin signaling is bi-directional, with forward signaling from ephrin- to Eph-expressing cells and reverse signaling from Eph- to ephrin-expressing cells. However, it is not clear whether this forward or reverse signaling plays a role in regulating the size of the neuroepithelial cell population during early brain development. Also, Eph receptors and their corresponding ligands are mutually exclusive in their expression domains, and they encounter each other only at interfaces between their expression domains. This expression pattern may be a critical mechanism for preventing overstimulation of Eph-ephrin signaling. Nevertheless, Eph receptors are co-expressed with their corresponding ligands in certain brain regions. Recently, two studies demonstrated that brain region-specific apoptosis may be triggered by the overlapping expression of Eph and ephrin, a theme that will be explored in this mini-review.
Apoptosis ; Brain ; Cell Death ; Embryonic Development ; Ephrins ; Female ; Ligands ; Neuroepithelial Cells ; Pregnancy ; Receptor, EphA1 ; Receptors, Eph Family

Epigenetic modification such as DNA methylation and histone acetylation plays essential roles in many aspects of cellular function and development of animals. There is an increasing amounts of evidence for dynamic changes in the histone acetylation of specific gene segments, but little attempt was made to examine global pattern changes in the histone acetylation in developing nervous system. In this study, we found that acetylated histone H3 and H4 immunoreactivities were relatively weak in neuroepithelial cells in the ventricular zone of developing rat cerebral cortex or chick spinal cord, compared to the immature young neurons in the cortical plate of a rat embryo or lateral motor column in chick spinal cord. On the other hand, adult neural stem cells in the dentate gyrus (DG) of rat hippocampal formation did not exhibit such diminished histone acetylation, compared to neuroblasts and mature DG neurons. These results suggest that the level of histone acetylation is highly dynamic and tightly linked to the neuronal types and the differentiation stages.
Acetylation ; Adult ; Animals ; Cerebral Cortex ; Dentate Gyrus ; DNA Methylation ; Embryonic Structures ; Epigenomics ; Hand ; Hippocampus ; Histones ; Humans ; Nervous System ; Neural Stem Cells ; Neuroepithelial Cells ; Neurons ; Rats ; Spinal Cord

Teratogenic effects of a diphenylhydantoin on the neurulation of the explanted early chick embryos were studied using the punched-out filter paper explantation technique. The 6th to 9th Hamburger and Hamilton staged chick embryos were explanted and cultured in the Ham's F-10 media treated with 15 microgram/ml, 30 microgram/ml, 60 microgram/ml, 90 microgram/ml, 120 microgram/ml of diphenylhydantoin in the CO2 incubator for 6-9 hours. The morphological chracteristics and the ultrastructural changes of the neuroepithelium of early chick embryos were compared with the control and experimental group using the stereomicroscope and the electron microscope. Of th 40 chick embryos cultured in the Ham's F-10 media without drug, 37 embryos(92.5%) developed normally and 3 embryos(7.5%) developed abnormally in 94 embryos(61.4%). The frequent anomalous features of the embryos were deformities of the neural folds in the cranial regions, failure of neural tube closure, dispersion of somites and developmental arrest. The scanning electron microscopic findings of neuropithelial cells of abnormally developed embryos were diminished surface blebs and microvilli, flattened and smooth cellular surfaces, and irregular size of cells. The transmission electron microscopic findings of neuroepithelial cells of abnormally developed embryos showed no significant changes of the development of intracellular organelles except the smooth cellular surface and mild underdevelopment of microfilaments.
Actin Cytoskeleton ; Animals ; Blister ; Chick Embryo* ; Congenital Abnormalities ; Embryonic Structures ; Incubators ; Microvilli ; Neural Crest ; Neural Tube ; Neuroepithelial Cells ; Neurulation* ; Organelles ; Phenytoin* ; Somites

Dysembryoplastic neuroepithelial tumors (DNETs) arise mostly in the supratentorial cerebral cortex. A very rare case of intraventricular DNET with diffuse ependymal involvement, which causes spinal drop metastasis, is presented.
Adult ; Diagnosis, Differential ; Ependymoma/*pathology/radiotherapy ; Female ; Humans ; Lumbosacral Region/*pathology ; *Magnetic Resonance Imaging ; Neuroepithelial Cells/pathology ; Spinal Neoplasms/radiotherapy/*secondary

OBJECTIVE: To explore the methods of isolation, culture and identification of brain tumor stem cells (BTSCs) in neuroepithelial tumor tissues in vitro, and to study the correlation between BTSCs and the patholorical grades of neuroepithelial tumors. METHODS: Tumor cells from patients undergoing neuroepithelial tumors excision were acutely dissociated, triturated into single cells, and then seeded into serum-free medium. After the primary brain tumor spheres (BTSs) were generated, they were triturated again and passaged in fresh medium. The expression of Nestin and CD133 of BTSs was detected by immunocytochemistry staining, and the expression of CD133 of tumor specimen sections was detected by immunohistochemistry staining . The expression of CD133 of 46 brain tumors and 5 normal brain tissues were analysed by SABC immunohistochemical staining, and the correlation between the expression and pathological grade of the tumors was analysed. RESULTS: BTSCs from neuroepithelial tumors could be isolated and cultured, and could be generated and passaged in vitro. The expression of Nestin and CD133 could be detected in BTSCs. CD133 could be detected in neuroepithelial tumor tissues, but not in normal brain tissues. There was significant difference between the expression of CD133 and the different grades of tumors (P < 0.01), and there was a positive correlation between the expression of CD133 and the histologic grading of tumors (P < 0.01). CONCLUSION A small proportion of stem cells have the ability to self-renew in human neuroepithelial tumors, and there is a positive correlation between the expression of CD133 and histologic grading of tumors.
AC133 Antigen ; Antigens, CD ; analysis ; Brain Neoplasms ; pathology ; Glycoproteins ; analysis ; Humans ; Intermediate Filament Proteins ; analysis ; Neoplasms, Neuroepithelial ; pathology ; Neoplastic Stem Cells ; pathology ; Nerve Tissue Proteins ; analysis ; Nestin ; Peptides ; analysis ; Tumor Cells, Cultured

Teratogenic effects of carbamazepine, an anticonvulsant, on the neurulation of the explanted early chick embryos were studied utilizing the punched-out filter paper explantation and culture technique. Fresh fertilized white leghorn hen eggs were incubated for 20-30 hours in an egg incubator. The Hamburger and Hamilton stage 4-11 chick embryos were explanted using the punched-out filter paper explantation technique and cultured in the CO2 cell culture incubator for 6-10 hours. They were randomly divided into a control group and an experimental group. The experimental group was divided into five subgroups according to the carbamazepine concentrations of 20micrometer 40micrometer 100micrometer 200micrometer 400micrometer with which the Ham's F-10 culture media were treated. The morphological characteristics and the incidences of teratogenic effects on the neurulation of early chick embryos in the control and experimental groups were compared with each other using the stereomicroscope and the electron microscope. The chick embryos of the same developmental stage were selected from the control and experimental groups, and immunohistochemical staining for fibronectin was done by the double-bridge PAP method. The results were as follows. 1) Of the 41 chick embryos cultured in the Ham's F-10 media without carbamazepine, 38 embryos(92.7%) developed normally, and 3 embryos(7.3%) developed abnormally. In contrast, among the 98 embryos cultured in the carbamazepine-treated media, 54 embryos(55.1%) developed abnormally. The frequent anomalous features were deformities of the neural folds, failure of neural tube closure, derangement of somites, and developmental arrest. 2) The frequency and severity of abnormal embryos increased in dose-dependent fashion. The embryos cultured in the media treated each with 20micrometer 40micrometer 100micrometer 200micrometer 400micrometer of carbamazepine developed abnormally in 12.5%, 21.1%, 60.0%, 81.0%, 86.4% respectively. 3) The scanning electron microscopic findings in neuroepithelial cells of abnormally developed embryos were flattened and smooth cellular surface with diminished surface blebs and microvilli, and size irregularity of the cells. On transmission electron microscope, underdevelopment of intracellular microfilaments was seen, but there was no significant change in the intracellular organelle. 4) The immunohistochemical stainability of the extracellular fibronectin at the basal side of the neuroepithelium was decreased in the carbamazepine-treated embryos.
Actin Cytoskeleton ; Animals ; Blister ; Carbamazepine ; Cell Culture Techniques ; Chick Embryo* ; Congenital Abnormalities ; Culture Media ; Culture Techniques ; Eggs ; Embryonic Structures ; Fibronectins* ; Incidence ; Incubators ; Microvilli ; Neural Crest ; Neural Tube ; Neuroepithelial Cells ; Neurulation* ; Organelles ; Ovum ; Somites

To figure out the occurrence pattern of pediatric brain tumors in the aspects of age, sex, location and histopathological diagnosis, 365 cases of pediatric(age less than 16 year) brain tumor which were operated upon at the Department of Neurosurgery, Seoul National University Hospital from January 1959 to June 1993, were reviewed. Only the tumors, of which the pathological specimens were taken, were included. Tumors of bone origin or purely extradural mass, non-tumorous cystic lesions and vascular malformations were excluded. The mean age of 365 cases was 8.1 years and the sex ratio(M : F) was 1.3 : 1. Supratentorial tumors(56.2%) were more prevalent than infratentorial tumors(43.4%). Neuroepithelial tumors comprised of 64.4% of the 365 brain tumors. Forth three percent of the neuroepithelial tumors were embryonal origin such as medulloblastoma(MBL), primitive neuroectodermal tumor(PNET) and ependymoblastoma. Pathological common tumors were astrocytic tumor(22.7%), MBL(20.0%), craniopharyngioma(13.4%), germ cell tumor(GCT, 8.8%), PNET(6.6%), and ependymal tumor(6.3%) in the order of decreasing frequency. PNET and ependymal tumors were frequent in early childhood while pituitary adenoma and non-teratomatous GCT were common in older children. GCT, PNET and ependymoma were prevalent in male. The relative incidences of GCT, PNET, brain stem glioma, oligodendroglial tumor, pituitary adenoma and neuronal tumor increased in MRI era. In contrast, those of astrocytic tumor, MBL and ependymal tumor decreased.
Adenoma ; Brain Neoplasms* ; Brain Stem ; Brain* ; Child ; Diagnosis* ; Ependymoma ; Germ Cells ; Glioma ; Humans ; Incidence ; Magnetic Resonance Imaging ; Male ; Neoplasms, Neuroepithelial ; Neural Plate ; Neuroectodermal Tumors, Primitive ; Neurons ; Neurosurgery ; Pituitary Neoplasms ; Seoul ; Vascular Malformations