Light Microscopic Histochemistry on Plastic Sections

摘要: As compared with conventional paraffin, celloidin, and frozen sections, semithin plastic sections offer a superior quality of the light microscopic image in terms better resolution, absence distortion shrinkage artifacts, suitability for calcified tissues. Application histochemical methods to such often encounters, however, serious difficulties resulting from considerably reduced reactivity plastic-embedded biological material. Factors involved include poor penetration reagents into embedding media due steric or hydrophobic hindrance, as well blockade reactive chemical groups sample interactions fixatives plastics. Embedding polar (hydrophilic) plastics, glycol methacrylate, permits carrying out large number reactions, including demonstration enzymatic activities, directly on but is less suitable combined light/electron studies because an imperfect ultrastructural preservation nonpolar epoxy resins, particularly if double aldehyde-osmium fixation, results high ultrastructure almost fully inhibits embedded In order restore this reactivity, i.e. unmask bound by polymerized resin, require removal matrix alkoxides prior procedure. Additional steps are also necessary: treatment osmium-fixed oxidative agents, e.g., hydrogen peroxide periodate which reoxidize osmium remove it tissue, controlled proteolytic digestion, especially useful immunocytochemical studies, probably cleaves bonds between primary aldehyde fixative, sites. This article reviews have been successfully applied Using methacrylates and/or resins media, has possible demonstrate proteins aminoacid residues, carbohydrates, lipids, nucleic acids, biogenic amines, inorganic ions, some enzymes, although spectrum found material far narrower than that available paraffin sections.(ABSTRACT TRUNCATED AT 400 WORDS)