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The expression of E-, N- and P-cadherin, alpha-, beta- and gamma-catenin, and actin was studied by immunohistochemistry, ELISA, and Western blot analysis in normal prostates, and in the prostates of men with benign prostatic hyperplasia and men with prostatic carcinoma, in order to evaluate their possible role in the pathogenesis of these diseases. Present results reveal that the immunophenotype of hyperplastic prostates differs from those of both normal and carcinomatous prostates in the intracellular distribution (observed by immunohistochemistry) and the intensity (measured by ELISA) of immunoreactions to cadherins, catenins, and actin. Hyperplastic prostates differ form normal prostates in the weaker immunoreaction to the three cadherin types, the two catenins, and actin, as well as in the intracellular distribution of P-cadherin, beta- and gamma-catenin, and actin. Differences between benign prostatic hyperplasia and prostatic carcinoma are less marked because hyperplastic prostates differ from carcinomatous prostates only in the weaker immunoreactions to P-cadherin, and alpha-catenin. The most remarkable findings in this study were: (1) alpha-catenin production was elevated in prostatic carcinoma in comparison with benign prostatic hyperplasia and normal prostate; and (2) P-cadherin expression in benign prostatic hyperplasia is reduced with regard to those of normal and carcinomatous prostates. It may be concluded that a decreased immunoreaction to cadherins, catenins, and actin, as well as changes in the intracellular distribution of actin in prostatic cells are not necessarily suggestive of malignancy, because these alterations are also present in BPH, and thus, the loss of cadherin-catenin-mediated adhesion alone is not sufficient to establish an invasive phenotype.

The presence and distribution pattern of paramyosin have been examined in different invertebrate muscle cell types by means of Western blot analysis and electron microscopy immunogold labelling. The muscles studied were: transversely striated muscle with continuous Z lines (flight muscle from Drosophila melanogaster), transversely striated muscle with discontinuous Z lines (heart muscle from the snail Helix aspersa), obliquely striated body wall muscle from the earthworm Eisenia foetida, and smooth muscles (retractor muscle from the snail and pseudoheart outer muscular layer from the earthworm). Paramyosin-like immunoreactivity was localized in thick filaments of all muscles studied. Immunogold particle density was similar along the whole thick filament length in insect flight muscle but it predominated in filament tips of fusiform thick filaments in both snail heart and earthworm body wall musculature when these filaments were observed in longitudinal sections. In obliquely sectioned thick filaments, immunolabelling was more abundant at the sites where filaments disappeared from the section. These results agree with the notion that paramyosin extended along the whole filament length, but that it can only be immunolabelled when it is not covered by myosin. In all muscles examined, immunolabelling density was lower in cross-sectioned myofilaments than in longitudinally sectioned myofilaments. This suggests that paramyosin does not form a continuous filament. The results of a semiquantitative analysis of paramyosin-like immunoreactivity indicated that it was more abundant in striated than in smooth muscles, and that, within striated muscles, transversely striated muscles contain more paramyosin than obliquely striated muscles.

A light and electron microscope immunocytochemical study and Western blotting analysis has been performed on intermediate filaments (vimentin, desmin and cytokeratins) in the testis of the teleost fish Gambusia affinis holbrooki. An immunoreaction to vimentin was observed in the epithelium of the efferent ducts, testicular canal and their surrounding peritubular cells. Positive vimentin immunostaining was also observed in the cells located around seminiferous tubules (boundary cells), Leydig cells, interstitial fibroblasts, chromatophores, and blood vessel endothelial cells. In contrast to mammals, no vimentin immunoreactivity was found in the Sertoli cells. Immunoreactivity to desmin was weak in the epithelial cells of the efferent ducts and testicular canal and intense in the peritubular cells that surrounded these ducts. Desmin immunoreactivity was also observed in the seminiferous tubule boundary cells. The immunoreactivity was weak in the boundary cells that surrounded germ cell cysts containing spermatogonia or spermatocytes and intense in the boundary cells around cysts with elongated or mature spermatids. Immunoreactivity towards cytokeratins was observed only in testicular blood vessels. Cytokeratin immunolabelling was intense in the endothelium and weak in the vascular smooth muscle cells. No cytokeratin immunoreactivity was found in the Sertoli cells, germ cells, interstitial cells or in the efferent duct epithelium. The absence of intermediate filaments in the Sertoli cells, the absence of cytokeratins in the epithelium of the sperm excretory ducts, and the presence of desmin filaments in these epithelial cells are the most important differences with regards to the intermediate filament phenotype in mammalian testes.