Summary
Congo Red is an acid-base indicator dye. In free solution the colour and absorption characteristics of Congo Red depend not only on the pH but are also governed by the nature of the solvent environment. In tissue sections stained by Congo Red, alteration of the pH and the use of non-aqueous solvents can effect differential colouring of the tissue components. Stained sections of unmodified and chemically substituted celluloses show that differential red or blue coloration reflects the acidic or basic character of the substrate. In stained tissue sections, secondary protein structure and porosity of the substrate may also influence their colour. The effect of non-aqueous solvents is probably to modify the ionization state of the dye- substrate complex, thus altering the colour of the Congo Red. Such solvents may also change the aggregation or solvation states of the dye, with consequent modification in the colour of tissue components.
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References
Baker, J. r. (1958)Principles of Biological Microtechnique, London: John Wiley.
Banyal, E. (1972) Acid-base indicators. InIndicators (edited byBishop, E.), pp. 74–75. Oxford: Pergamon Press.
Barnard, K., Partridge, S. m., Whiting, A. h., Fantl, V. &Mccullagh, K. g. (1982) Immunological studies with human aortic elastin.Conn. Tis. Res. 9, 233–40.
Covington, A. k. &Dickinson, T. (1973)Physical Chemistry of Organic Solvent Systems. London: Plenum Press.
Davies, J. d. &Young, E. w. (1982) Congo blue: a rapid stain for elastic fibres.J. clin. Path. 35, 789–91.
Davies, J. d., Young, E. w., Mera, S. l. &Barnard, K. (1983) Lysozyme is a component of human vascular elastic fibres.Experientia 39, 382–3.
Davies, J. d. &Mera, S. l. (1983) Congo “blue” staining: A histochemical problem.Bristol Med-Chi. J. 98, 90.
Dickerson, R. e. &Geis, I. (1969)The Structure and Action of Proteins, New York: Harper and Row.
Eanes, E. d. &Glenner, G. g. (1968) X-ray diffraction studies on amyloid filaments.J. Histochem. Cytochem. 16, 673–7.
Finar, A. l. (1967)Organic Chemistry. Vol. 1 5th edn. pp. 835–6. London: Longmans.
Highman, B. (1946) Improved methods for demonstrating amyloid in paraffin sections.Arch. Path. 41, 559–62.
Horobin, R. w. &James, N. t. (1970) The staining of elastic fibres with Direct Blue 152. A general hypotheses for the staining of elastic fibres.Histochemie 22, 324–36.
Horobin, R. w. &Flemming, L. (1980) Structure-staining relationships in histochemistry and biological staining.J. Microsc. 119, 357–72.
Janz, G. j. &Tomkins, R. p. t. (1972)Non-aqueous Electrolytes Handbook. Vol. 1 London: Academic Press.
Kulonen, E. &Pikkarainen, J. (1970) Comparative studies of the chemistry and chain structure of collagen. InChemistry and Molecular Biology of the Intercellular Matrix (edited byBalazs, E.), pp. 81–97. London: Academic Press.
Lendrum, A. c., Fraser, D. s., Slidders, W. &Henderson, R. (1962) Studies on the character and staining of fibrin.J. clin. Path. 15, 401–13.
Lendrum, A. c., Sidders, W. &Fraser, D. s. (1972) Renal hyalin. A study of amyloidosis and diabetic fibrinoid vasculosis with new staining methods.J. clin. Path. 25, 373–96.
Lian, J. b., Aviram, M., Skinner, M., Cohen, A. s. &Lees, R. s. (1980) The dissociation of secondary amyloid fibrils into constitutents related to serum amyloid protein and apolipoprotein. InAmyloid and Amyloidosis (edited byGlenner, G. g., Pinho e costa, P. andFalcao de freitas, A.), pp. 1–13. Amsterdam Excerpta Medica.
Lloyd, D. j., Dempsy, M. &Farrod, M. (1946) The swelling of protein fibres in organic solvents.Trans. Faraday Soc. 428, 228–44.
Lucas, F., Shaw, J. t. b. &Smith, S. g. (1958) The silk fibroins.Adv. Protein Chem. 13, 107–242.
Mckay, R. b. &Hillson, P. j. (1966) Metachromatic behaviour of dyes in solvents of low dielectric constant.Trans. Faraday Soc. 62, 1439–46.
Mckay, R. b. &Hillson, P. j. (1967) Metachromatic behaviour of dyes in solvents of high dielectric constant: the anomaly of water.Trans. Faraday Soc. 63, 777–80.
Padday, J. f. (1970) Metachromasy of dyes in solution. InChemistry and Molecular Biology of the Intercellular Matrix (edited byBalazs, E.), pp. 1007–31. London: Academic Press.
Pearse, A. g. e. (1968)Histochemistry: Theoretical and Applied. Vol. 1. 3rd edn. London: J. & A. Churchill.
Puchtler, H., Sweat, F. &Levine, M. (1962) On the binding of Congo Red by amyloid.J. Histochem. Cytochem. 10, 355–64.
Ross, R. (1973) The elastic fibre: a review.J. Histochem. Cytochem. 21, 199–208.
Tribe, C. r. &Perry, V. a. (1979) Diagnosis of amyloidosis.Assoc. Clin. Pathol. Broadsheet 92, 1–9.
West, W. &Geddes, A. l. (1964) The effects of solvents and of solid substrates on the visible and molecular absorption spectrum of cyanine dyes.J. Phys. Chem. 68, 837–47.
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Mera, S.L., Davies, J.D. Differential Congo Red staining: The effects of pH, non-aqueous solvents and the substrate. Histochem J 16, 195–210 (1984). https://doi.org/10.1007/BF01003549
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DOI: https://doi.org/10.1007/BF01003549