Staining by numbers: A tool for understanding and assisting use of routine and special histopathology stains

摘要

Most benchworkers consider successful histopathological staining as a matter of skills, experience, and rules of thumb. This article champions a further factor: making useful predictions concerning stains and staining using QSAR (quantitative structure-activity relations) models, for instance, when selecting new stains, or modifying old stains, or trouble-shooting problem stains. QSAR models require a description of properties of stain molecules by numbers, with these numbers being used to make predictions and to understand what's happening. Key numerical parameters ("numbers") describe electric charge, overall size of a dye or dye ion, hydrophilicity/lipophilicity, and size of a dye's aromatic system. Simple case examples discussed are the nature of acid and basic dyes; the effects of staining rates on demonstration of mucins with basic dyes; the control of lipid staining by dye lipophilicity; and influence of the size of a dye's conjugated system on high-affinity staining. More complicated applications of QSAR models are also discussed, namely the selection of alternative stains to alcians blue and yellow; avoidance of stain loss during washing, cleaning, and mounting; and identification of positive artifacts, specifically background staining occurring with resin embedded specimens. Do-it-yourself staining by numbers also is discussed.