[Conformation preserving methods of fixation (author's transl)]

For immune- and enzymehistochemical studies it is necessary to preserve biological activities of fixed cells and tissues. Aldehyde fixed biological materials give not in all cases results to provide for the needs in histochemistry, because aldehydes depressed by conformational changes of macromolecules strongly their antigen-, antibody- and enzyme-activity. Thus, it is successful a fixation by mild cross linking fixatives. Carbodiimides, diimidate compounds as well as other bifunctional reagents are excellent reagents, which can preserve in the most parts the genuine biological peculiarities of the cells. Several examples of their histochemical employment are introduced and are further discussed.