Figure 3 : Analysis of the interface within the renal stem/progenitor cell niche by transmission electron
microscopy.

Specimens were fixed by glutaraldehyde (a), glutaraldehyde including lanthanum (b), alcian blue (c), cupromeronic blue (d),
ruthenium red (e) or tannic acid (f). It is demonstrated that mesenchymal and epithelial cells are separated by an interface
(asterisk). Projections of mesenchymal cells cross the interface to contact a CD ampulla.
(a) Fixation by glutaraldehyde exhibits a bright interface separating mesenchymal and epithelial cells.
(b) Fixation by glutaraldehyde including lanthanum shows an inconspicuous interface.
(c) Fixation by glutaraldehyde including alcian blue illustrates that projections of mesenchymal cells are enveloped by filigree
extracellular matrix in form of a sleeve (serrated arrow).
(d) Fixation by glutaraldehyde including cupromeronic blue illustrates buckles of proteoglycans on the basal aspect of epithelial
stem/progenitor cells and on mesenchymal cell projections (arrow).
(e) Fixation by ruthenium red shows that a labeled band of extracellular matrix surrounds a CD ampulla. In some areas the
interface is bright, while in other areas a punctuate pattern of extracellular matrix is seen.
(f) Fixation by glutaraldehyde containing tannic acid shows a dense coat on the basal lamina of a CD ampulla. Distinct areas
of the interface are bright, while others contain filigree extracellular matrix. The basal lamina (lamina rara (L.r.), lamina
densa (L.d.) and lamina fibroreticularis (L.f.)) at the tip of 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