Occurrence of mallory body‐like inclusions in parathyroid chief cells of ozone‐treated dogs

Ultrastructural characteristics of chief cells of the parathyroid glands of ozone‐treated dogs were examined 3 days, 10–13 days and 28 days after treatment. Dilated Golgi cisternae and vacuoles contained low electron dense fibrillar material. These changes in the Golgi were accompanied by massive accumulation of filaments in the perinuclear area where most of the cell organelles were disrupted to the peripheral zone of the filamentous inclusions. These inclusions were not enclosed by a membrane and corresponded with PAS‐positive and diastase‐resistant material in the chief cells at light microscopic level. Therefore these inclusions were arbitrarily designated as Mallory body‐like inclusions.