Use of Thick Histochemical Preparations, Whole Mount Cultured Cells or Thick Sections from Embedded Tissues, for Three-Dimensional Observation by Ultrahigh Voltage Electron Microscopy

We have observed very thick biological specimens, both whole mount cultured cells and thick sections from embedded tissues, which were stained with histochemical reactions for specific cell organelles, by means of high or ultrahigh voltage electron microscopy (UHVEM).Thick histochemical specimens, both whole mount cultured cells and semithin sections from embedded tissues were used. Two cell strains in culture, one established CHO-K1 cell line and the other primary culture cells of adult Wistar rat hepatocytes were used. Culture cells were seeded onto formval coated gold meshes and incubated in CO2 incubator. CHO-K1 cells were cultured in Ham’s F12 medium containing HRP (1 mg/ml), while rat hepatocytes were in L-15 medium containing Clofibrate (0.2 mM). The cultured cells were stained with DAB reaction, dried in a critical point dryer (Hitachi HCP-1). Thick sections (0.2-1.0 μm) from DEHP fed rat livers, fixed in 2.5% glutaraldehyde, stained with DAB reaction, postfixed in 1% osmium tetroxide and embedded in Epon, or semithin Epon sections (0.2μm) from the pancreases of 3H-thymidine or 3H-uridine injected mice, fixed doubly, radioautographed with Sakura NR-H2 emulsion.