Figure 4: Toluidine blue staining (4a-c) and histochemical label for SBA (4df), Laminin γ 1 (4g-i), Cingulin (4j-l) and Collagen III (4m-o). Toludine blue stained cryosections show numerous tubules (T) covered at the upper and lower side by I-7 fleece layers consisting of polyester fibers (PF) (a). At Posi- 4 (b) and Posi-5 (c) polyester fleeces toludine blue stain demonstrates that tubules develop between the fleece layers as well as between the polyester fleece fibers. Cryosections reveal after SBA-label numerous tubules containing a basal lamina (asterisk) and a lumen (arrow) (d-f). The basal lamina of all generated tubules is positive for Laminin γ 1 (g-i). Positive label for Cingulin exhibt polarization in all of the epithelial cells (j-l). Collagen type III (m-o) labels the basal lamina as well as interstitial fibers. Newly synthesized extracellular matrix (О).