[Histochemistry of copper and copper-binding protein in liver with a comparison between histologic sections and...

A quantitative analysis of copper in liver tissue and a qualitative analysis of copper-binding protein in the histologic sections were subjected to correlative study. Liver sections, obtained from autopsies and surgical resections, were examined histopathologically by orcein staining, rhodanine staining, and other special stainings, in addition to hematoxylin eosin (HE) staining. The quantitative analysis was carried out by an atomic absorption spectrophotometry. Copper and copper-binding protein were not detectable by HE staining. The amount of orcein positive granules (OPGs) was graded semiquantitatively from negative (-) to three plus ( ). The average copper content was 24.9 micrograms/g dry liver weight (micrograms/g) in (-) group, 60.9 micrograms/g in (+) group, 158.9 micrograms/g in (++) group, and 299.3 micrograms/g in ( ) group respectively. Although the copper content and the amount of OPGs were relatively well correlated as mentioned above, standard deviations of copper contents were comparatively large in each group, especially in (++) or ( ) group. Based upon the comparative study of staining qualities of various dyes, rhodanine staining and orcein staining were specific for copper or copper-binding protein. Finally, orcein staining was thought to be the most excellent method from the viewpoints of sensitivity, specificity, contrast and simplicity. The distribution of excessive copper in pathologic conditions was fairly uneven. We recommend a histopathologic examination by using many liver sections stained by orcein, when the condition of copper overload is suspected.