ATTEND NEUROSCEINCES MEETINGS IN ORLANDO, NOVEMBER, 2002 |
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Welcome to the Orange County Convention Center, site of the 2002 Neuroscience Meetings where two Unversity of Delaware undergraduate students presented their research in Poster Sessions. |
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Erin Henninger and Alexandra Cretu |
OF FIBRONECTIN BY RADIAL GLIA IN DEVELOPING BRAIN. Erin
M.Henninger; D.S.Galileo
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Neurons migrate along radial glial cell guides during brain development. It has been shown previously that the cell adhesion receptor 8 1 integrin plays a key role in mediating this migration and also in survival via an unidentified substrate. Fibronectin (Fn) and several other potential extracellular matrix (ECM) substrate proteins were considered. Immunohistochemistry was used to determine which substrates were expressed in developing chick optic tectum (OT). Radial glia were identified with a monoclonal antibody specific for vimentin and ECM molecules were identified with polyclonal antibodies. Cryostat sections of OT from embryonic days 6-12 (E6-E12) were double-label immunostained for vimentin and one of the suspected ECM molecules. The sections indicated specific staining patterns of Fn along the radial glia. Other ECM molecules either did not display positive staining or did not display a pattern indicative of radial migration. Immunolocalization was carried out also in suspended cells from dissociated OT and analyzed on a flow cytometer. Results showed expression of Fn by most, if not all, radial glia and some neurons. Finally, dissociated optic tectum cells were cultured and treated with Brefeldin A, to accumulate intracellular Fn. Confocal microscopy indicated the accumulation of fibronectin within radial glia, whereas Fn surrounding neuronal cells appeared to be on the cell surface. These results demonstrate that radial glia express Fn, which is then aligned along their surfaces. This suggests a potential role for radially oriented Fn in neuronal migration and survival during brain development. Supported in part by NIH/NINDS. |
XENOGRAFT MODEL FOR STUDY OF GLIOMAS. Alexandra
Cretu; G.R.Molloy;
D.S.Galileo
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Adhesion molecules play important roles during development of the nervous system, such as in axon extension, fasciculation and neuronal migration. Some gliomas express adhesion molecules such as L1, which may facilitate their local invasiveness in brain, especially along axonal tracts. We have developed a new xenograft model to test the role of adhesion molecules like L1 in glioma cell invasiveness. Human and rat glioma cell lines were injected into the ventricle of early chick embryos on E5 to assess their ability to grow and to form invasive tumors. Tumor lines tested included U-87, C6, 9L, and a modified 9L line that was made to express NgCAM (chick L1). All lines expressed the lacZ marker gene to facilitate their observation. Brains were analyzed at various times up to two weeks after injection by X-gal staining and routine paraffin histology. All lines grew and formed tumors in the embryonic chick brain. Intraventricular tumors became highly vascularized by chick brain microvasculature. C6 was the most invasive into brain tissue, U-87 was somewhat invasive, and 9L generally stayed confined to perivascular areas. Thus, behavior of the different glioma lines was generally similar to that in the rodent brain. This demonstrates the potential usefulness of our new model for future studies of gliomas. |