Figure 4 : Details of the interface within the renal stem/progenitor cell niche analyzed by transmission
electron microcopy.

After fixation of specimens with glutaraldehyde (a), glutaraldehyde including lanthanum (b), alcian blue (c), cupromeronic
blue (d), ruthenium red (e) or tannic acid (f). In all of cases can be seen that mesenchymal cell projections line through the
interstitial interface (asterisk) to contact a CD ampulla.
(a) Fixation by glutaraldehyde shows that mesenchymal cells are separated from epithelial stem/progenitor cells by a
bright interface.
(b) Fixation by glutaraldehyde including lanthanum shows an inconspicuous interface.
(c) Fixation by glutaraldehyde including alcian blue demonstrates that the end of a cell projection is integrated in filigree
extracellular matrix in form of a sleeve (serrated arrow).
(d) Fixation by glutaraldehyde including cupromeronic blue illuminates that buckles of proteoglycans (arrow) connect
the basal aspect of epithelial stem/progenitor cells and the surface of mesenchymal cell projections.
(e) Fixation by ruthenium red illustrates a broad label surrounding the tip of a CD ampulla and contacting projections
of mesenchymal cells. In part the interface shows a punctuate pattern, while other areas are bright.
(f) Fixation by glutaraldehyde containing tannic acid shows on a CD ampulla a dense label. Restricted areas of the
interface are bright, while others contain filigree extracellular matrix contacting cell projections. The basal lamina
(lamina rara (L.r.), lamina densa (L.d.) and lamina fibroreticularis (L.f.)) on a CD ampulla is marked by a cross (+).

Minuth et al.Stem Cell Biology and Research  2014 1:4DOI : 10.7243/2054-717X-1-4