"Pop-off" technic. The ultrastructure of paraffin-embedded sections.

Stained paraffin embedded sections sometimes contain a precise area that warrants further investigation at an ultrastructural level. A technic is described whereby an area in question may be reembedded into plastic and sectioned for examination under the electron microscope. The decoverslipped paraffin section is "popped-off" into an inverted BEEM capsule. Suspected viral inclusions in sections may be identified or ruled out with this technic. Special stains, especially heavy metal applications, not able to be utilized in conventional plastic embedding may be reembedded into plastic. The metallic granules may be visualized ultrastructurally without further grid staining. This method is especially helpful for cell smears and cell monolayers since they may be the only material available for study. Although ultrastructural detail is often poor, one does have the ability to study the identical section under both the light and the electron microscopes.