Electron Microscopy after the Application of Lanthanum as Tracer Particles and Ionic Stain

Abstract

[Human] lenses with pseudoexfoliation (PE) were suspended in a solution of La, which was present partly in ionic form, partly as electron-dense tracer particles in colloidal solution, dependent on pH and on the concentration of La. By EM the tracer particles were found in a narrow zone along the surface of the PE excrescences. Only a few of the smallest particles had penetrated into their most superficial layer. In the specimens treated with ionic La, the effect was an electron-dense staining of the PE material within a 1-2 .mu.m thick superficial layer. The PE fibrils and parts of the interfibrillar spaces were stained. Proteoglycans were found. An interfibrillar matrix apparently excludes other macromolecules and particles from penetrating into the material.