[Improved methods for the cytochemical demonstration of platelet peroxidase (author's transl)]

The variability of results to demonstrate the peroxidase of platelets has been attributed to an inhibition of the enzyme by glutaraldehyde. In order to eliminate this difficulty, two new methods have been employed prior to incubation in the diaminobenzidine medium: 1. Fixation was omitted. 2. Fixation was performed in a mixture of tannic acid-formaldehyde glutaraldehyde. With these two procedures, intense and reproducible peroxidase staining of human platelets and chicken thrombocytes was obtained. Only when the fixation procedure was omitted could the peroxidase of rat platelets be demonstrated histochemically. The importance of the detection the peroxidase as a marker enzyme of the megakaryocyte cell line and the relationships of this peroxidase with those of leukocyte peroxidases are discussed.