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Notes on the Marchi method for staining degenerating myelin i

Notes on the Marchi method for staining degenerating myelin i

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doi: 10.1136/jnnp.31.2.110 1968 31: 110-114 J Neurol Neurosurg Psychiatry S J Strich system. peripheral and central nervous staining degenerating myelin in the Notes on the Marchi method for http://jnnp.bmj.com/content/31/2/110.citation Updated information and services can be found at: These include: References http://jnnp.bmj.com/content/31/2/110.citation#related-urls Article cited in: service Email alerting online article. article. Sign up in the box at the top right corner of the Receive free email alerts when new articles cite this Notes http://jnnp.bmj.com/cgi/reprintform To order reprints of this article go to: http://jnnp.bmj.com/subscriptions go to: Journal of Neurology, Neurosurgery & Psychiatry To subscribe to group.bmj.com on February 17, 2010 - Published by jnnp.bmj.com Downloaded from
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J. Neurol. Neurosurg. Psychiat., 1968, 31, 110-114 Notes on the Marchi method for staining degenerating myelin in the peripheral and central nervous system SABINA J. STRICH From the Department of Neuropathology, Institute of Psychiatry, London S.E.5 The Marchi method for staining degenerating myelin (Marchi, 1886) has exasperated and intrigued many because it is so useful yet prone to disturbing artefacts and because the reaction of osmium tetroxide with tissue components has interesting theoretical implications (Adams, 1965). Essentially, tissues are placed in a mixture of osmium tetroxide and an oxidizing agent such as KC103; degenerating myelin then becomes black, whereas normal sheaths remain unstained. The method has been used mainly to demonstrate so-called Wallerian degeneration: when a nerve fibre is interrupted, the axon and myelin sheath of the piece severed from the cell body degenerate and the breakdown products of this process can be stained with Marchi fluid. There are contradictory views about the chemical nature of the material which reduces osmium tetroxide in this procedure. Thus the material which stains with the Marchi method has been characterized as a lipid, probably cholesterol ester, by some (Adams, 1958; Wolfgram and Rose, 1958; Adams, 1960) and as a polysaccharide by others (Wolman, 1956, 1957). Conflicting opinions have also been expressed about the persistence of this material in the degenerating neural tissue. Some workers state that the method is only useful two to five weeks after the interruption of myelinated nerve fibres (Mettler and Hanada, 1942), whereas others have obtained satisfactory preparations from three days (Glees, 1948) to many months after the onset of the degenera- tion (Glees, 1943; Smith, 1956a). Similarly some authorities (Swank and Davenport, 1934; Mettler and Hanada, 1942; Glees, 1943) insist that the tissue to be stained should not be fixed for more than 48 hours, otherwise there may be loss of stainable material or increased artefacts; others claim good results, in some cases, years after fixation in formalin (Smith, 1956a; Smith, Strich, and Sharp, 1956).
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