Structure-staining relationships in histochemistry and biological staining. I. Theoretical background and a general account of correlation of histochemical staining with the chemical structure of the reagents used.

A description is given of the choice, rationale and calculation of several numerical coefficients for describing the chemical structures of staining reagents such as dyestuffs, enzyme substrates, diazonium and tetrazolium salts. Using such coefficients, structure-staining correlations may be made for many staining systems. Examples include the structural correlations of the quantitative affinity measurements of the staining of chromatin with basic dyes, the tetrazolium salts for use as visualizing agents in enzyme histochemistry, and the use of bis-azo compounds as acid or basic dyes, or as fat stains. The value of such structure-staining correlation models for assisting the rational selection and design of new histochemical reagents, and for understanding old reagents and procedures, is discussed.