Ultrastructural Examination and Technical Developments

In this issue of Ultrastructural Pathology focus is on technical aspects. Optimal processing has always been an important matter and is reflected in regular contributions in the journal. During the last few years we have published papers on the use of energy- dispersive X-ray in diagnostics [[1], [2]], the use of immuno-EM on material retrieved from paraffin [[3]], the application of infrared microspectroscopic detection of epithelial and stromal growth [[4]], and ultrastructural telepathology [[5]].

In this issue Soheir Mansy reports a technical development in handling cells in suspension [[6]]. Such cells are usually embedded in a supporting medium before processing for electron microscopy. Mansy has used an agarose gel as an embedding medium for sediments from urine samples. The low melting point of the agarose makes it more appealing to manipulate Mansy compared this processing method with the standard one and found that more cells were available for examination, a more uniform distribution of cells was seen, and the cells were better preserved [[6]]. In addition, a simultaneous processing of the block both for light microscopy and electron microscopy is an advantage in cytology.

Barshack and coworkers [[7]] present a new method for processing wet tissue without fixation and complex preparation procedures. Specimens are imaged in sealed specimen capsules and separated from the evacuated interior of the electron microscope by a strong, thin, electron-transparent membrane. Imaging was done in an SEM and with use of backscattered electron microscopy. A resolution up to 20 nm was achieved without the use of dehydration or coating [[7]].

Palestrant and coworkers [[8]] examined microbial biofilms in the gut by EM and used acridine orange staining for confirmation. Fresh frozen tissues stained with acridine orange revealed biofilms in the mucus lining normal gut epithelium. In most studies so far no biofilms have been reported, but many micrographs of bacteria are presented. The commonly used preparation methods, washing with saline or fixation with aldehyde, tend to disrupt the biofilms. Thus, confirmation with another method as shown in this study leads to the conclusion that biofilms are a normal phenomenon in the gut [[8]].