Nuclear and cytoplasmic microfilaments in the pineal chief cells of the rat

An ultrastructural study of intranuclear rodlets in a malignant extracranial neuroepithelial neoplasm

This report describes for the first time the presence of intranuclear rodlets in a malignant extracranial neuroepithelial neoplasm. This malignant neoplasm appeared poorly differentiated by light microscopy and presented initially as a diagnostic problem. Electron microscopy revealed neoplastic cells joined by macula adherens-type junctions and containing numerous interdigitating cell processes diagnostic of a neuroepithelial neoplasm. A quantitative analysis of 500 cells revealed the presence of intranuclear rodlets in 5% of the neoplastic cells. The rodlets were composed of individual filaments that measured 7-9 nm in width. An extensive review of the literature revealed the high frequency of reported rodlets in normal neurons, normal paraneurons, neoplasms of the nervous system, and paraneuromas. The significance of this interesting structure to the physiology of the cell is discussed.

Origin, development, and nature of intranuclear rodlets and associated bodies in chicken sympathetic neurons

Correlative data are presented here on the developmental history, dynamics, histochemistry, and fine structure of intranuclear rodlets in chicken sympathetic neurons from in vivo material and long-term organized tissue cultures. The rodlets consist of bundles of approximately 70 +/- 10 A proteinaceous filaments closely associated with approximately 0.4-0.8 micro spheroidal, granulofibrillar (gf) bodies of a related nature. These bodies are already present in the developing embryo a week or more in advance of the rodlets. In early formative stages rodlets consist of small clusters of aligned filaments contiguous with the gf-bodies. As neuronal differentiation progresses these filaments increase in number and become organized into well-ordered polyhedral arrays. Time-lapse cinemicrography reveals transient changes in rodlet contour associated with intrinsic factors, changes in form and position of the nucleolus with respect to the rodlet, and activity of the gf-bodies. With the electron microscope filaments may be seen extending between the nucleolus, gf-bodies, and rodlets; nucleoli display circumscribed regions with fine structural features and staining reactions reminiscent of those of gf-bodies, We suggest that the latter may be derivatives of the nucleolus and that the two may act together in the assemblage and functional dynamics of the rodlet. The egress of rodlet filaments into the cytoplasm raises the possibility that these might represent a source of the cell's filamentous constituents.