Initially, biological specimens were prepared for EM by negative staining, a method in which the specimen is dried and embedded in a layer of electron-dense heavy metal salts, which provides high contrast for imaging in the electron microscope.
Interestingly, we noted patches of apposed ER cisternae separated by a thin layer of electron dense cytosol, resembling the apposed ER cisternae reported by Borgese and coworkers.
The chorionic layer of electron dense material is seen covering the exochorion structure of the eggs.
Furthermore, the SC of SASP−/− mice showed 7 10 layers of electron dense and tightly compacted cell layers compared with that of SASP+/+, which usually exhibited 5 7 layers (Fig 2C H).
First of all, this is the absence of a continuous layer of electron-dense inclusions as well as practically completes absence of phagosomes – debris of the photoreceptor outer segments phagocytized by pigment epithelium, whirling extensions of the basement membrane into the cytoplasm.
SASP−/− hairless mice showed a marked decrease in SC hydration and an increased number of electron dense layers in the SC.
After fixation with glutaraldehyde-OsO4-tannic acid, a film of electron dense material external to the TL-layer is recognisable, probably due to a precipitation of tannic acid; moreover, the inner polysaccharide layer becomes more evident.
A variety of electron dense labels, including peroxidase, ferritin, colloidal gold, and more recently quantum dots, have been used as markers in electron microscopy.
In some regions, the cortical layer showed accumulation of electron dense material and the placement of the epicuticle was mis-specified as it was within the cortical layer instead of at the apical surface of the cuticle.
A discontinuous layer of an electron dense substance was observed beneath the boarder between the endothelial layer and Descemet's membrane (fig 5).
Electron microscopy of peripheral ventricular cell layers in uninjured hearts revealed subepicardial cardiomyocytes with prominent myofilaments and groups of electron dense mitochondria and a single layer of epicardial cells (Fig. 3A).
