[A new electron microscopic method of determining acidification in phagocyte subcellular structures].

A new method is elaborated for detecting acidification in phagocytes on the ultrastructural level. The method is based on the reaction between Cu2+ and [Fe(CN)6]4- which form a pellet of cupric ferrocyanide in the neutral medium. It is possible to induce pellet formation under definitely determined pH values on adding different amounts of chelating agent (citrate) to the reaction mixture. The fine-grained electron dense pellet of cupric ferrocyanide persists throughout the whole subsequent procedure of fixation, dehydration and embedding of the biological material for electron microscopy. Data are presented on the degree of acidification and its localization in subcellular structures of the phagocyte during phagocytosis.