Search results for "Myelin Sheath"
showing 5 items of 55 documents
Disturbed structural connectivity in schizophrenia primary factor in pathology or epiphenomenon?
2007
Indirect evidence for disturbed structural connectivity of subcortical fiber tracts in schizophrenia has been obtained from functional neuroimaging and electrophysiologic studies. During the past few years, new structural imaging methods have become available. Diffusion tensor imaging and magnetization transfer imaging (MTI) have been used to investigate directly whether fiber tract abnormalities are indeed present in schizophrenia. To date, findings are inconsistent that may express problems related to methodological issues and sample size. Also, pathological processes detectable with these new techniques are not yet well understood. Nevertheless, with growing evidence of disturbed structu…
Brain lateralization probed by water diffusion at the atomic to micrometric scale
2019
International audience; Combined neutron scattering and diffusion nuclear magnetic resonance experiments have been used to reveal significant interregional asymmetries (lateralization) in bovine brain hemispheres in terms of myelin arrangement and water dynamics at micron to atomic scales. Thicker myelin sheaths were found in the left hemisphere using neutron diffraction. 4.7 T dMRI and quasi-elastic neutron experiments highlighted significant differences in the properties of water dynamics in the two hemispheres. The results were interpreted in terms of hemisphere-dependent cellular composition (number of neurons, cell distribution, etc.) as well as specificity of neurological functions (s…
Sonic hedgehog promotes the migration and proliferation of optic nerve oligodendrocyte precursors.
2007
Optic nerve (ON) oligodendrocyte precursors (OPCs) are generated under the influence of the Sonic hedgehog (Shh) in the preoptic area from where they migrate to colonise the entire nerve. The molecular events that control this migration are still poorly understood. Recent studies suggested that Shh is often used by the same cell population to control different processes, including cell proliferation and migration, raising the possibility that Shh could contribute to these aspects of OPC development. In support of this idea, we show here that Shh induces the proliferation of OPCs derived from embryonic mouse ON explants and acts as a chemoattractant for their migration. In ovo injections of …
Combined pre- and postnatal ethanol exposure in rats disturbs the myelination of optic axons.
2011
Aims: To analyse myelination and outgrowth of the optic axons in relation to the neuro-ophthalmological manifestations of ethanol (EtOH) abuse during pregnancy. Methods: An experimental model of chronic EtOH exposure was developed in rats and their offspring by subjecting the dams to a liquid diet (35% of the daily total calories as either EtOH or maltose-dextrose nutritional controls (Con). Eyeballs and optic nerves were obtained at key developmental stages and processed for morphologic, immunocytochemical and immunoblotting procedures, using alternatively antibodies against myelin basic protein (MBP) or neurofilament (NF) protein, and image analysing. Results: A significant delay in onset…
Fresh cell therapy followed by fatal coma
1986
A 60-year-old woman received a 3-day course of nine injections of “fresh” cells from fetal lamb ovary, placenta, brain (hypothalamus) and liver. There were no immediate complications, but a few days later she developed headache, fever and hemiparesis. She subsequently fell into a coma and died 3 weeks after her fresh cell therapy and 2 weeks after the onset of her clinical symptoms. Autopsy revealed perivenous leucoencephalopathy with a probably steroid-treatment-induced paucity of perivascular inflammation. Fresh cell therapy, clinical symptomatology and morphological findings suggest, though do not prove, that this patient's monophasic and probably immune-mediated disease is a rare and fa…