Focal areas of @entity730 are frequent in @entity35 myocardium 30 and 60 days after administration of @entity19295 . These areas are PAS-positive, stain deeply with alcian blue and show high affinity for colloidal @entity68 . Calcification is almost completely confined to intracellular structures. Small clusters of needle-shaped crystals are first found in apparently undamaged mitochondria in undamaged myocardial cells. When all the mitochondria are calcified, the cell degenerates, and inorganic crystals are laid down in relationship with its myofilaments. In other myocardial cells, clusters of amorphous or finely granular inorganic substance are found in both mitochondria and myofibrils. Both structures show signs of @entity528 . Inorganic substance has only occasionally been found within the structures of the sarcoplasmic reticulum. These structures do not seem to be involved in @entity296 under the present experimental conditions. Calcification of myocardial cells gives rise to a cellular reaction. Many macrophagic cells surround the calcified areas, which are rapidly reabsorbed. The present results show that myocardial mitochondria are actively engaged in controlling the intracellular concentration and movement of @entity460 ions. Their role in the myocardial contraction-relaxation cycle and the possible mechanism of @entity296 are discussed.

Experimental XXXX of the myocardium. Ultrastructural and histochemical investigations.

@entity296 :: ('MESH:D009202', 'Disease') :: ['myocardial calcification'] @entity19295 :: ('MESH:D004097', 'Chemical') :: ['dihydrotachysterol'] @entity730 :: ('MESH:D002114', 'Disease') :: ['calcification'] @entity460 :: ('MESH:D002118', 'Chemical') :: ['calcium'] @entity35 :: ('10116', 'Species') :: ['rat'] @entity528 :: ('MESH:D009410', 'Disease') :: ['advanced degeneration'] @entity68 :: ('MESH:D007501', 'Chemical') :: ['iron']
@entity730 :: (MESH:D002114,Disease) :: ['calcification']
