title: Ribosome-submembranous density complex. A new specialized cell unit.
abstract: Ultrastructural study of a malignant meningioma revealed an organelle complex composed of: (1) A band-like densification of the cell cytoplasm adjacent to and in contact with the cell membrane. (2) An arciform filament immediately subjacent to it, with concavity directed away from the cell membrane. (3) A row of regularly spaced ribosomes located in the concavity, but at some distance from the arciform filament. (4) A pericellular condensation of interstitial ground substance. Occasionally, a second, thinner filament was seen "threading" the ribosomes together. Its morphology was consistent with that described for messenger RNA . It is suggested that the ribosomes are engaged in the synthesis of proteins for other portions of the organelle complex and that the ultimate role of the specialized unit would be that of an attachment device.
mesh_terms: D002462:Cell Membrane / Q000648:ultrastructure; D005260:Female; D006801:Humans; D008577:Meningeal Neoplasms / Q000648:ultrastructure; D008579:Meningioma / Q000648:ultrastructure; D008854:Microscopy, Electron; D008875:Middle Aged; D009940:Organoids / Q000648:ultrastructure*; D012270:Ribosomes / Q000648:ultrastructure