title: A reliable method with good cell preservation for the demonstration of peroxidase activity in human platelets and megakaryocytes.
abstract: We have tried to improve existing methods for demonstration of platelet peroxidase (PPO) in human platelets and megakaryocytes by introducing a fixation of 0.1% glutaraldehyde prior to incubation in the DAB medium. This prefixation with low concentration of glutaraldehyde preserves excellent morphological detail and does not inhibit PPO activity. All 23 platelet-rich plasma samples show PPO reaction product in the dense tubular system after incubation in DAB medium with 0.003% H2O2. When 0.01% H2O2 is used in excessive DAB medium, PPO activity can also be demonstrated in platelets and megakaryocytes of bone-marrow cell suspensions. This method can be used for the identification of megakaryoblasts in acute non-lymphocytic leukemia, myelodysplastic syndromes and in blastic crisis of chronic myeloid leukemia. PPO cytochemistry can be combined with postfixation in a OsO4-ruthenium red mixture. This method reveals alpha-granules, dense bodies, microtubuli, glycogen, mitochondria, dense tubular system and invaginated membrane system in the same platelet and is useful for investigation of platelet ultrastructure.
mesh_terms: D001792:Blood Platelets / Q000201:enzymology* / Q000648:ultrastructure; D005404:Fixatives; D005976:Glutaral; D006651:Histocytochemistry; D006801:Humans; D008533:Megakaryocytes / Q000201:enzymology* / Q000648:ultrastructure; D008854:Microscopy, Electron; D009940:Organoids / Q000201:enzymology; D010544:Peroxidases / Q000097:blood / Q000378:metabolism*; D012430:Ruthenium Red
chemical_list: D005404:Fixatives; D012430:Ruthenium Red; D010544:Peroxidases; D005976:Glutaral