Second edition, volume 2, section Pityriasis. Four descriptive varieties and the objection that one usage of nigra lacks scaling. This is a pre-1865 text, not a modern taxonomy.

British and Foreign Medico-Chirurgical Review 35(69), January 1865, pp. 248–259. Section XII, pp. 255–256, reports narrowed coronary openings and aortic and cardiac plexus disease in a case of angina; a contemporary report of a case is not proof of a necessary cause.

A pericyte is a vessel-associated biological cell located along the outside of small blood vessels, closely associated with endothelial cells. Pericytes help regulate vessel maturation and barrier properties. In mice with reduced pericyte coverage, vascular permeability and transport across the blood-brain barrier change; this connects a surrounding support cell to the function of the endothelial cell barrier. Coverage, anatomical location and functional evidence should be considered together when identifying pericytes. ^[ref]

A melanocyte is a pigment-producing biological cell that synthesizes melanin in specialized compartments called melanosomes. In skin, melanosomes are transferred to neighbouring keratinocytes, so the site of pigment production differs from much of its final distribution. Melanin helps attenuate ultraviolet radiation; differences in pigmentation depend on pigment production and handling, rather than simply the number of melanocytes. ^[ref]

A specialized contact connecting neighbouring biological cells or connecting a cell to its surroundings.

Different junctions perform different tasks: an adherens junction mechanically couples cells, a tight junction regulates passage between them, and a gap junction permits selected intercellular exchange. The shared category therefore specifies an organized contact rather than one universal permeability or mechanical function. ^[ref]

A giant cell is a conspicuously large biological cell, often containing several cell nuclei. It can arise by fusion of separate biological cells or by repeated nuclear division without completed cytokinesis. These routes differ experimentally: more DNA or more nuclei does not establish that cell fusion occurred. Macrophage fusion produces some inflammatory giant cells, whereas normal specialized large cells also occur. The term describes morphology rather than one developmental lineage. ^[ref]