Revisiting vimentin expression in early chick development

Histogenesis of human renal cell carcinoma by using electron microscopy and immunohistochemical techniques

Electron microscopy and immunohistochemical techniques are powerful tools for the determination of tissue origin. Both techniques have been used in the current experiment for histogenesis of renal cell carcinoma. Fifty kidney tumors were subjected to immunohistochemical detection for intermediate filaments cytokeratin and vimentin, which are normally expressed in epithelial tissue and mesenchymal tissues, respectively. Twenty cases of the above were examined by electron microscopy for detection of ultrastructure features. From each kidney, two specimens were taken, one from the diseased area and another far from it to serve as a control. Immunohistochemical study revealed in cases of renal cell carcinoma, cytokeratin and vimentin were expressed alone in 44% of cases, and 40% of cases, respectively. Twelve percent of cases were coexpressed with both cytokeratin and vimentin. Electron microscopic study of diseased specimens revealed the expression of desmosomes which was observed in almost all tumor specimens. The expression of the vimentin in some cases either alone or with cytokeratin was interpreted as a change in the characters of some tumor cells which indicates the need for additional techniques in such cases to get the proper interpretation. The prevalence of the expression of cytokeratin and the persistence existence of desmosomes indicate the epithelial origin of the tumor. This data is very beneficial for determination of line of therapy and follow up of the patients. The results confirm the power of combined use of both immunohistochemistry and electron microscopy in the field of histogenesis.

Histology and Ultrastructure of the Equine Lingual Tonsil. I. Crypt Epithelium and Associated Structures

The microstructural and ultrastructural features of the equine lingual tonsil were studied in five young horses. Located at the root of the tongue it presented an irregular surface with rounded elevations, numerous folds and crypts. Stratified squamous non-keratinized epithelium lining its outer surface was modified by heavy infiltration of lymphoid cells to form reticular epithelium within the crypt. The latter implies a role in initiating and maintaining immune responses to incoming infectious agents and antigens. Lamellated structures resembling Hassall's corpuscle were observed towards the outer surface epithelium. Microplicae were visible by scanning electron microscopy on the surface of both the outer and reticular epithelia. No microvillus cells resembling M cells were observed. The stratum superficiale of the reticular epithelium showed strong affinity for Soybean (SBA), Phosphocarpus tetragonolobus 1 (WBA 1), Ulex europaeus (UEA) and Griffonia simplicifolia 1 isolectin-B4 (GS1-B4). The characteristic lectin binding patterns may be useful for embryological and microbiological investigations. Vimentin filaments were not detected consistent with absence of M cells. Mucus glandular acini in the deeper lamina propria mucosae contained glycogen, acidic, neutral and weakly sulphated mucopolysaccharides. Transmission electron microscopy revealed that the layers of the outer surface and reticular epithelia shared characteristic features except the stratum superficiale, which had nuclei of varying shapes and an abundance of cell organelles. A few mast cells with electron lucent granules and myelinated nerve fibres were localized in the deeper portion.