Editing Amyloid (section)

==Definition==
The name ''amyloid'' comes from the early mistaken identification by [[Rudolf Virchow]] of the substance as [[starch]] ({{Lang|la|amylum}} in [[Latin]], from {{Langx|grc|ἄμυλον|translit=amylon}}), based on crude [[iodine-staining]] techniques. For a period, the scientific community debated whether or not amyloid deposits are [[lipid|fatty]] deposits or [[carbohydrate]] deposits until it was finally found (in 1859) that they are, in fact, deposits of [[albumin|albumoid]] proteinaceous material.<ref>{{cite journal | vauthors = Kyle RA | title = Amyloidosis: a convoluted story | journal = British Journal of Haematology | volume = 114 | issue = 3 | pages = 529–38 | date = September 2001 | pmid = 11552976 | doi = 10.1046/j.1365-2141.2001.02999.x | s2cid = 23111535 | doi-access =  }}</ref>
* The classical, [[histopathology|histopathological]] definition of amyloid is an extracellular, proteinaceous [[fibrillar]] deposit exhibiting [[β-sheet]] [[Secondary structure of proteins|secondary structure]] and identified by apple-green [[birefringence]] when stained with [[congo red]] under [[Polarization (waves)|polarized light]]. These deposits often recruit various sugars and other components such as [[serum amyloid P component]], resulting in complex, and sometimes inhomogeneous structures.<ref>{{cite journal | vauthors = Sipe JD, Cohen AS | s2cid = 16442783 | title = Review: history of the amyloid fibril | journal = Journal of Structural Biology | volume = 130 | issue = 2–3 | pages = 88–98 | date = June 2000 | pmid = 10940217 | doi = 10.1006/jsbi.2000.4221 }}</ref> Recently this definition has come into question as some classic, amyloid species have been observed in distinctly intracellular locations.<ref name="pmid17353506">{{cite journal | vauthors = Lin CY, Gurlo T, Kayed R, Butler AE, Haataja L, Glabe CG, Butler PC | title = Toxic human islet amyloid polypeptide (h-IAPP) oligomers are intracellular, and vaccination to induce anti-toxic oligomer antibodies does not prevent h-IAPP-induced β-cell apoptosis in h-IAPP transgenic mice | journal = Diabetes | volume = 56 | issue = 5 | pages = 1324–32 | date = May 2007 | pmid = 17353506 | doi = 10.2337/db06-1579 | doi-access = free }}</ref>
* A more recent, [[biophysics|''biophysical'']] definition is broader, including any polypeptide that polymerizes to form a cross-β structure, ''in vivo'' or ''in vitro'', inside or outside [[Cell (biology)|cells]]. [[Microbiologists]], [[biochemists]], [[biophysicists]], [[chemists]] and [[physicists]] have largely adopted this definition,<ref name="pmid15283924">{{cite journal | vauthors = Nilsson MR | title = Techniques to study amyloid fibril formation in vitro | journal = Methods | volume = 34 | issue = 1 | pages = 151–60 | date = September 2004 | pmid = 15283924 | doi = 10.1016/j.ymeth.2004.03.012 }}</ref><ref name="pmid17530168">{{cite journal | vauthors = Fändrich M | title = On the structural definition of amyloid fibrils and other polypeptide aggregates | journal = Cellular and Molecular Life Sciences | volume = 64 | issue = 16 | pages = 2066–78 | date = August 2007 | pmid = 17530168 | doi = 10.1007/s00018-007-7110-2 | s2cid = 32667968 | pmc = 11138455 }}</ref> leading to some conflict in the biological community over an [[Linguistic prescription|issue of language]].