TY - JOUR T1 - The cutaneous amyloidoses: Pathogenesis and therapy AU - Breathnach SM Y1 - 1985/04/01 N1 - 10.1001/archderm.1985.01660040054011 JO - Archives of Dermatology SP - 470 EP - 475 VL - 121 IS - 4 N2 - The term amyloidosis refers to the extracellular deposition of an abnormal protein material with characteristic tinctorial properties and ultrastructural features.1 Under the electron microscope, amyloid deposits consist largely of a loose network of 7.5 to 10-nm rigid, linear, nonbranching, aggregated, paired fibrils of indefinite length and with hollow cores on profile.2 Infrared spectroscopy and X-ray diffraction crystallography have revealed that amyloid fibrils are usually composed of polypeptide chains arranged perpendicularly to the long axis of the fibril with the conformation of a meridional, antiparallel, β-pleated sheet.3,4 During the course of purification of extracted amyloid fibril preparations, a further amyloid tissue protein, quite separate from the fibrillar component of amyloid deposits, was identified.5 This novel amyloid tissue protein, termed amyloid P (plasma) component (AP) because of its antigenic identity to an α-globulin in the blood of normal individuals,6 may represent up to 14% by weight of extracted amyloid material.1 SN - 0003-987X M3 - doi: 10.1001/archderm.1985.01660040054011 UR - http://dx.doi.org/10.1001/archderm.1985.01660040054011 ER -