title: The fine structural localization of endogenous and exogenous peroxidase activity in human bone marrow mast cells under pathological conditions.
abstract: We have examined the ultrastructural characteristics of peroxidase activity in human bone marrow mast cells. These studies were performed in three patients with systemic mast cell disease, and in another six patients showing bone marrow mast cell hyperplasia. Endogenous peroxidase activity was localized in the perinuclear cisternae and strands of endoplasmic reticulum, but never in the granules. We have also demonstrated the "in vivo" existence of exogenous peroxidase activity in two of the three cases of systemic mast cell disease. The peroxidase internalization involved its binding to the plasma membrane, followed by its incorporation into the cell by a general endocytic process comprising the uptake of dispersed peroxidase-positive material mainly by phagocytosis of granular structures containing peroxidase. The exogenous peroxidase appeared in non-membrane bound granules, vacuoles or aggregates, but we have never seen the enzyme linked to the mast cell granules.
authors.affiliation: Department of Haematology, Hospital Ramón y Cajal, Universidad de Alcalá de Henares, Madrid, Spain.
authors.forename: L M
authors.initials: LM
authors.lastname: Escribano
authors.forename: E
authors.initials: E
authors.lastname: Villa
authors.forename: L
authors.initials: L
authors.lastname: Gabriel
authors.forename: B
authors.initials: B
authors.lastname: Heinrichs
authors.forename: J
authors.initials: J
authors.lastname: Perez de Oteyza
authors.forename: M D
authors.initials: MD
authors.lastname: Valdés
authors.forename: J L
authors.initials: JL
authors.lastname: Aranda
authors.forename: J L
authors.initials: JL
authors.lastname: Navarro
mesh_terms: D000328:Adult; D000368:Aged; D001853:Bone Marrow / Q000201:enzymology*; D006801:Humans; D008297:Male; D008407:Mast Cells / Q000201:enzymology* / Q000648:ultrastructure; D008415:Mastocytosis / Q000201:enzymology*; D008854:Microscopy, Electron; D008875:Middle Aged; D010544:Peroxidases / Q000032:analysis*
chemical_list: D010544:Peroxidases