From Big Medical Encyclopedia

CONGO RED (German. Kongorot; synonym congo red) — the azoic dye which is applied to coloring of animal fabrics and products of their life activity, derivative benzidine.

Red-brown powder, water soluble and alcohol. Solutions K. in alkaline and neutral condition red, in acid — blue. Property K. to get blue coloring in acid medium it is used during the definition free salt to - you in a gastric juice, for overseeing by change of reaction of digestive vacuoles of protozoa during the coloring by their weak solutions K. At intravenous administration of 0,01 — 0,1% of solutions K. the amyloid which is contained in fabrics is painted in rose-red color. In this regard To. apply to intravital identification of amyloid at animals in an experiment and to recognition of the latent forms of an amyloidosis in clinic (see. Bennkholda test ).

To. apply to identification in gistol. cuts of amyloid on Bennkhold's way in Pukhtler's modification, for coloring of elastic fibers on Matsuura's way, for coloring of obkladochny and main cells of glands of a mucous membrane of a stomach. During the studying of processes of ossification 0,3% solution K are used., painting a neogenic bone tissue in brick-red color. To. it is applied also to coloring of a keratin in epidermis, to identification of fabric localization of the polyvinylpirrolidone entered into blood, etc.

See also the Benzidine dyes , Histologic methods of a research .

Bibliography: Lille R. Patogistologicheskaya of the technician and a practical histochemistry, the lane with English, page 477, M., 1969; Merkulov G. A. Course of the patologogistologichesky equipment, page 281, L., 1969; Pearce E. A histochemistry, the lane with English, page 255, etc., M., 1962.

Ya. E. Hesinonim