Myelin isolation

The data in Table 4-1 indicate that myelin accounts for much of the total lipid of white matter, and that the lipid composition of gray matter is quite different from that of myelin. The composition of brain myelin from all mammalian species studied is very much the same. There are, however, some species differences for example, myelin of rat has less sphingomyelin than does that of bovine or human (Table 4-1). Although not shown in the table, there are also regional variations for example, myelin isolated from the spinal cord has a higher lipid-to-protein ratio than brain myelin from the same species. 

Ogawa-Goto K, Funamoto N, Ohta Y, Abe T, Nagashima K (1992) Myelin gangliosides of human peripheral nervous system An enrichment of GMl in the motor nerve myelin isolated from cauda equina. J Neurochem 59 1844—1849. 

Ogawa-Goto, K., Ohta, Y., Kubota, K., Funamoto, N., Abe, T., Taki, T., and Nagashima, K. (1993). Glycosphingolipids of human peripheral nervous system myelins isolated from cauda equina. J. Neurochem. 61 1398-1403. 

R = / -C H ), in low doses, exhibits the former behavior and is used primarily as an extradural agent in obstetrics. The lowest effective extradural concentration of etidocaine (21, X = CH, R = R = 2H, R = / -C H ), however, shows both adequate sensory and profound motor blockade so that it is useful in surgical situations where maximum neuromuscular blockade is necessary. In an isolated nerve preparation, bupivacaine blocks unmyelinated C fibers which are mainly responsible for pain perception at a much greater extent than the myelinated A fibers which carry motor impulses. It is postulated that absorption of bupivacaine by the vasculature at the site of injection, combined with the slow diffusion of this agent, results in an insufficient amount of the drug penetrating the large A fibers to cause motor conduction blockade. Clinically, motor block can be observed in some procedures. 

Component of the myelin sheath surrounding the axons of nerve cells. Additional compounds of the myelin sheath are phospholipids, cholesterol, cerebrosides, and specific keratins. The myelin sheath constitutes an isolating barrier during electrophysiological axonal signaling. 

Boulias, C., Pang, H., Mastronardi, F., and Moscarello, M. A., The isolation and characterization of four myelin basic proteins from the unbound fraction during CM52 chromatography, Arch. Biochem. Biophys., 322, 174, 1995. 

The composition of myelin is well characterized because it can be isolated in high yield and purity by subcellular fractionation 56 Central nervous system myelin is enriched in certain lipids 56 Peripheral and central nervous system myelin lipids are qualitatively similar 58... 

Lemke, G., Lamar, E. and Patterson, J. Isolation and analysis of the gene encoding peripheral myelin-protein zero. Neuron 1 73-83,1988. 

Taylor, K.S., G.D. Waller, and L.A. Crowder. 1987. Impairment of a classical conditioned response of the honey bee (Apis mellifera L.) by sublethal doses of synthetic pyrethroid insecticides. Apidologie 18 243-252. Theophilidis, G., M. Benaki, and E. Papadopoulu-Mourkidou. 1997. Neurotoxic action of six pyrethroid insecticides on the isolated sciatic nerve of a frog (Rana ridibunda). Comp. Biochem. Physiol. 118C 97-103. Tippe, A. 1987. Evidence for different mechanisms of action of the three pyrethroids, deltamethrin, cypermethrin, and fenvalerate, on the excitation threshold of myelinated nerve. Pestic. Biochem. Physiol. 28 67-74. 

EGF-responsive neural stem cells isolated from rat and mouse brain are capable of differentiating into oligodendrocytes and of forming myelin following transplantation into the myelin deficient rat. Duncan, I.D., Archer, D.R., Hammang, J.P. (1993). Abstr Soc Neurosci, 19 (1-3) Abs 689. 

We obtained unexpected findings using this method to study myelin the oxidation by galactose oxidase of myelin-bound cerebrosides could not be detected. The oxidation did not occur either with the intact spinal cord preparation, with isolated myelin, or even with lyophilized myelin. In one experiment, lyophilized myelin containing 5 mg each of dry weight was incubated with 100, 200, and 500 units of galactose oxidase for 60 min at room temperature, and no cerebroside oxidation occurred. 

B30. Burns, J., Rosenzweig, A., Zweiman, B., and Lisak, R. R, Isolation of myelin basic protein-reactive T cell lines from normal human blood. Cell. Immunol. 81, 435-440 (1993). 

Habler et al. (1990, 1992) examined the functional properties of unmyelinated and myelinated primary afferent neurons innervating the pelvic viscera in anesthetized cats. The axons were isolated from the intact dorsal root and the intact or chronically de-efferented ventral root of segment S2. The responses of the neurons were studied with natural stimulation of the urinary bladder using innocuous or noxious increases of intravesical pressure. 

TakigawaT, YasudaH, KikkawaR, Sliigeta Y, Saida T, KitasatoH(1995) Andbodies against GMl ganglioside affect K+ and Na+ cunents in isolated rat myelinated nerve fibers. Ann Neui ol 37 436-442. 

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