Marchin.
/ˈmɑːki/, U.S. /ˈmɑrki/ Pathology.
1. attributive and (now rarely) in the genitive. Designating a method of fixing and staining nerve tissue to identify degenerating myelin, which is selectively stained black; esp. in Marchi method, Marchi technique. Also: designating the combination of reagents (a solution of potassium bichromate and osmium tetroxide) employed in this method.
ΚΠ
1900 A. Hill tr. H. Obersteiner Anat. Central Nervous Organs (ed. 2) i. 30 Marchi's method of staining is most sensitive to degenerative changes in nerve-tissue.
1926 H. M. Carleton Histol. Technique xiii. 262 The same remarks regarding the time limits of its application apply as to the Marchi technique.
1970 C. R. Leeson et al. Textbk. Histol. (ed. 2) x. 211/1 Osmium tetroxide blackens myelin and when used with potassium bichromate (Marchi stain), demonstrates degenerating fibers.
1974 C. F. A. Culling Handbk. Histol. & Histochem. Techniques (ed. 3) 450 It is said that Marchi's fluid may be used directly as a fixative.
1990 Brain 113 305 The corticospinal tract consists mainly of small diameter fibres, many of which will not be stained by the Marchi method, but they run intermingled with the larger Marchi-stained fibres.
2. attributive. Employing, or resulting from the use of, the Marchi method.
ΚΠ
1936 Arch. Neurol. & Psychiatry (Chicago) 35 847 Lorente de Nó..agreed with our solution of the problem after having studied our Marchi preparations.
1968 Brain 91 601 Ranson, Ranson and Ranson..did not find them [sc. the pallido-fungal fibres] degenerated in their Marchi studies in the macaque.
1990 Brain 113 305 Much of our material consists of Marchi preparations as they show degenerating fibres very clearly.
3. Marchi-positive adj. stained black by the Marchi technique; containing degenerating myelin identified by such staining.
ΘΚΠ
the world > health and disease > healing > diagnosis or prognosis > tests > [adjective] > reactions to tests
Schick-positive1927
Schick-negative1932
Marchi-positive1956
1956 Jrnl. Neurol., Neurosurg. & Psychiatry 19 67/1 Black-stained, Marchi-positive material was present in some of the cases only.
1976 Jrnl. Compar. Neurol. 170 191 The Marchi-positive bodies and argyrophilic granules, which are present in normal white matter, represent different histochemical expressions of the same entity—the myelinoid body.
1987 Lancet 12 Dec. 1365 Marchi-positive degeneration was found in the cords of 3 professional divers.
1993 Progress in Neurobiol. 40 319 These bodies are Marchi-positive and argyrophilic.
This is a new entry (OED Third Edition, September 2000; most recently modified version published online March 2022).
<
n.1900