Intracytoplasmic inclusion bodies in hepatocytes during prolonged extracorporeal circulation

Hyaline inclusion bodies appeared in hepatocytes of acutely congested livers produced by prolonged extracorporeal circulation. The inclusions were positive by PAS, PTAH and Ziehl-Neelsen staining and were colored light green to green by Masson's trichrome staining. In methylene blue-stained sections, they were divided into two groups, pale to light blue (Type I) and dark blue (Type II). By electron microscopy, small vacuolar structures which contained small amounts of flocculent material appeared near the vascular pole of hepatocytes at early stages of the experiment. With lapse of time, they became larger and had compact amorphous material. These inclusions corresponded to the Type I inclusions seen by light microscopy. By electron microscopic cytochemistry, these inclusions were usually positive to the acid phosphatase reaction and negative to the DAB reaction. With an increase in serum free hemoglobin, electron-dense inclusions corresponding to the Type II inclusions appeared in the hepatocytes. They were strongly positive to the DAB reaction. Large ones were usually positive to the acid phosphatase reaction in the peripheral narrow rim. Large invaginations of cytoplasmic membranes and large hydropic vacuoles were observed at the late stage of the experiment. They contained frequently fibrin strands or a few erythrocytes. Autophagic vacuoles and myelin figures were also increased in the hepatocytes at the late stage of the bypass circulation.