HISTOCHEMICAL METAL UPTAKE REACTIONS OF THE BILE PIGMENTS OF OBSTRUCTIVE ICTERUS AND OF HEMATOIDIN

Mordanting with CrO 3 and K 2 Cr 2 O 7 : but not with K 2 CrO 4 induces acetic hematoxylin staining (pH 2.5) of bile pigment granules, bile casts and erythrocytes in icteric human livers. Mordanting with tri- or divalent salts of Cr, Fe, Cu, and Sn also induces hematoxylin staining of these objects at pH levels determined by the specific requirements of the metal ion concerned. Mordant concentrations of 1, 10 and 50 mM were used for Cr , Fe , Fe ++ , Cu ++ and Sn ++ salts. Higher concentrations yielded somewhat denser staining, but did not extend the pH range of hematoxylin staining downward. Cr required a hematoxylin pH level of 6-7, Cu ++ of 5-7, Fe of 2.8-7, Fe + of 5-7 and Sn ++ of 2.8-7. Alkaline pH levels were not used. Fe and Fe ++ uptake were also shown by the positive Prussian and Turnbull's blue reactions obtained after both valency mordantings, indicating partial reduction of Fe and partial oxidation of Fe ++ . Fe ++ and Sn ++ are bound equally well by bile cases in untreated sections and in sections previously reduced 24 hr in 0.1 M H 2 SO 3 mixtures. Colors produced were blue-black for hexavalent and trivalent Cr, black for Fe and Fe ++ , dark blue for Cu ++ and dark red for Sn ++ . Hematoidin colors blue-black with acetic hematoxylin after 6-hr 0.2% CrO 3 oxidation, with and without prior dithionite desiderization of the concurrently present hemosiderin in pulmonary, cerebral and splenic infarcts.