Binding of lectin Ricinus communis agglutinin-1 (RCA-1) to rat brain tumors.

These results demonstrate that vim entin is present in the epithelial cells of renal tubules involved in foci of nonsup-purative interstitial nephritis, one of the most common in-flammatory processes of the bovine kidney.' Vimentin is frequently expressed in human renal cell carcinomas, 10 which are assumed to arise from tubular cells, and in tubular epi-thelial cells during the course of various nonneoplastic renal diseases in humans beings and rats.' The metanephric origin of the renal epithelial cells may explain the possible expression of vim entin in tubules affected by several pathologic conditions, such as tumoral dedifferentiation, active regen-eration, or damage due to interstitial infiltration, and sclerosis , In such conditions, tubular cells reexpress the intermediate filament protein present in the embryonal mesenchyme, namely vimentin.'? In vitro studies have demonstrated that the expression of vimentin in bovine renal epithelial cells may be induced by the presence oflow cell density in monolayer culture-or when desmosomal cell contacts are disrupted. 3 These observations suggest that the presence of vimentin in tubular epithelial cells is influenced by mutual contact and the extracellular environment.' The changes that occur in the peritubular environment in foci of interstitial nephritis probably act as the promoters of vim entin expression in tubular cells. The biological significance of this phenomenon is not understood, although it indicates a severe modification of the tubules during the course of interstitial nephritis. Further studies are needed to determine if this structural modification may interfere with the functional activity of the nephron. References Azumi N, Battiflora H: The distribution of vimentin and keratin in epithelial and nonepithelial neoplasms. Am J Clin Pathol 88:286-296, 1987 2 Ben-Ze'ev A: Differential control of cytokeratins and vim entin synthesis by cell-cell contact and cell spreading in cultured epithelial cells. junctional complexes in cultured epithelial cells is followed by the inhibition of cytokeratin and desmoplakin synthesis. Exp Cell Res 164:335-352, 1986 4 Gown AM, Vogel AM: Monoclonal antibodies to human intermediate filament proteins. II. Distribution of filament proteins in normal human tissues. Coexpression of keratin and vim entin in damaged and regenerating tubular epithelia of the kidney. Use of avidin-biotin-per-oxidase complex (ABC) in immunoperoxidase techniques: a comparison between ABC and unlabeled an-tibody (PAP) procedures. The catalog of human cytokeratins: patterns of expression in normal epithelia, tumors and cultured cells. Cell 31:11-24,1982 9 Raymond WA, Leong AS: Co-expression of cytokeratin and vimentin intermediate filament proteins in benign and neoplastic breast epithelium. …