Preliminary Electron Microscope Study Research Articles

An electron microscopic study of human thyroid cells in vitro

The morphology of suspensions of trypsinized human thyroid cells has been studied under the electron microscope and it has been established that these cells are derived from the thyroid secretory epithelium and not from any other cell type. In addition a preliminary electron microscopic study has been made of the cytotoxic effect of complement-fixing thyroid antibody on these human thyroid cells in vitro. The morphological changes are compared with the sequence of events seen under phase contrast microscopy.

Pinocytosis in the rabbit corneal endothelium.

Introduction In view of the demonstration that rabbit corneal epithelium actively transports sodium, 1,2 a preliminary electron microscopic study of this structure was undertaken. Previous electron microscopic studies had been primarily concerned with the characterization of the fibrous components of the cornea, and the specialized staining used to study these fibers did not present the cellular elements to best advantage. It was hoped that by examining unstained preparations a possible anatomic site for such active transport might be identified or that, at least, pinocytosis might be seen in the epithelium as a conceivable mechanism by which sodium ions are transported across this multicellular layer. The results of this attempt were disappointing: although clear electron micrographs of the epithelium were readily obtained, no structures suggestive of pinocytosis were demonstrated. An examination of the endothelium not only confirmed Speakman's 3 and Jakus' 4,5 observations of numerous mitochondria in these cells but also

Electron microscope study of the human neuromuscular junction.

A preliminary electron microscope study of human neuromuscular junction is presented. The biopsy material was taken from the palmarus longus, and fixed routinely in osmium tetroxide and embedded in methacrylate. The structure of the motor endings and the relationship of the synaptic vesicles to the axolemmal membrane are described. The synaptic clefts are filled with an homogeneous material in continuity with the basement membrane covering the muscle fiber. The subneural apparatus is described, and special attention is paid to a vesicular component present in the sarcoplasm of the junctional area, which differs from synaptic vesicles and is presumed to be a derivate of the sarcoplasmic reticulum.

ELECTRON MICROSCOPY OF LYSOSOME-RICH FRACTIONS FROM RAT LIVER

A preliminary electron microscope study has revealed the presence in lysosome-rich fractions, isolated from rat liver, of hitherto undescribed cytoplasmic particles, called "dense bodies." Approximately 0.37 micro in length, the dense bodies often possess an internal cavity and external membrane. They contain many electron-dense granules 55 to 77 A, or less, in diameter. Such dense bodies are also visible in electron micrographs of parenchymatous cells in liver sections. The correlations between dense bodies and lysosomes are listed, but until pure preparations are available it is not possible to assert that dense bodies and lysosomes are identical.

A Preliminary Electron Microscope Study of the Active Deposit from Radiothorium

A Preliminary Electron Microscope Study of the Active Deposit from Radiothorium