A double embedding technique for the electron microscopic analysis of the liver acinus

A double embedding technique allowing accurate and systematic sampling of zones of the hepatic acinus by electron microscopy was developed. The method involved the primary embedding of large (10 mm x 30 mm x 0.5 mm) liver slices and the preparation of 10 micrometers thick tissue sections by means of a rotary microtome with a steel knife. Veins 20--40 micrometers in diameter, the landmarks of the hepatic acinus, were localized by light microscopy, dissected from surrounding tissue and reembedded for ultramicrotomy. The method facilitated the systematic evaluation of hepatocyte ultrastructure in each zone of the microcirculatory unit of the liver, the hepatic acinus.