[Immunomorphological methods for identifying cells of the APUD system of the digestive organs].

Possibilities of application of immunomorphologic methods to gastrointestinal apud cells study were evaluated. These are: immunofluorescent, immunoenzyme, immune-peroxidase, peroxidase-antiperoxidase, avidinbiotin. Causes of immunologic and non-immunologic non-specific background staining and the means of its elimination are discussed, as well as problems of fixation and embedding of the material.