[Immuno- and enzymehistochemical studies of methacrylate-embedded biopsy material, especially iliac crest biopsies].

Immunohistochemical and histochemical methods are increasingly used and their application in surgical pathology is obvious. Especially we used these methods on bone marrow core biopsies. Optimal and comparable results have been obtained by using different methods after halving the biopsy cores longitudinally and/or transversally. The two halves were used for cytologic imprints. Two parts of the biopsy cores were embedded in polymethacrylate at low temperature (-20 degrees C). The methacrylate-embedded biopsy part for routine histology was fixed in Schaffer's solution (methanol-formalin-fixative). The methacrylate-embedded undecalcified section of 4 microns may be stained by most stains commonly employed in routine histopathology after removal of the plastic. The sections are virtually free of artefacts such as shrinkage and swelling in the light microscope. The second methacrylate-embedded part of biopsy cores was fixed in 2% paraformaldehyde with 5% sucrose in 0.02 M phosphate buffer (pH 7.4) and dehydrated in ethyleneglycolmonobutylether. All procedures were carried out at 4 degrees C. This method permits the use of immunohistochemical and histochemical procedures. The immunohistochemistry was carried out at sections of 4 microns after removal of the plastic with methoxide and use of proteolytic enzyme (0.1% alpha-chymotrypsin) to unmask antigens in sections. Surface and intracellular immunoglobulins were very well detected with the indirect FITC method. The histochemical procedures are carried out at sections of 7-8 microns after removal of plastic with xylene and toluol. The sections were incubated for specific esterase and nonspecific esterases, acid and alkaline phosphatase and then examined by light microscopy. A third part of biopsy cores may be immediately frozen, and cryostat sections are stained and evaluated for rapid diagnosis and used for immunohistologic analysis with mono- and polyclonal antibodies (FITC method) and/or histochemical investigations. Imprints of biopsy cores are evaluated for cytological, cytochemical and/or immunocytological analysis with mono- and polyclonal antibodies (FITC method). The cryostat sections and the imprints are fixed for all methods with 2% paraformaldehyde and 5% sucrose in PBS (0.02 M, pH 7.4) at 4 degrees C for 30 minutes. The best diagnostic results were obtained in the myelo- and lymphoproliferative disorders using the combination of methods described here. Examples were demonstrated.