Figure 2. Lanthanum penetration through the extracellular pathway.

In normal control skin (left panel), electron dense lanthanum tracer permeation is halted at the stratum granulosum – SC junction, whereas in ichthyosis vulgaris (right panel), tracer permeates beyond the junction, but remains restricted within the extracellular lamellar lipid pathway. Freshly obtained skin biopsies were exposed to 4% colloidal lanthanum nitrate tracer in 0.05 M Tris buffer, pH 7.4, for one hour, containing 2% glutaraldehyde and 2% paraformaldehyde, followed by post-fixation in OsO₄. Magnification bars = 1 µm (left panel), and = 2 µm (right panel).