Human Structure Virtual Histology
    Slide Preparation and Staining: Special stains
     
    		 

    Masson's trichrome: A three-color staining protocol used to differentiate cells from surrounding connective tissue. Most recipes produce red keratin and muscle fibers, blue or green collagen and bone, light red or pink cytoplasm, and dark brown to black cell nuclei. The trichrome is applied by immersion of the fixated sample into Weigert's iron hematoxylin, and then two different solutions.
    Periodic acid-Schiff stain (PAS): A staining method used primarily to identify glycogen in tissues. The reaction of periodic acid selectively oxidizes the glucose residues, creates aldehydes that react with the Schiff reagent and creates a purple-magenta color. A suitable basic stain is often used as a counterstain. PAS staining is mainly used for staining structures containing high proportion of carbohydrate macromolecules (glycogen, glycoprotein, proteoglycans), typically found in eg. connective tissues, mucus, and basal laminae.
    Alcian blue (AB): Alcian blue is a phthalocyanine dye that contains copper. The dye stains acid mucopolysaccharides and glycosaminoglycans, for which it is one of the most widely used cationic dyes; the stained parts are blue to bluish-green. It is sometimes combined with H&E staining and van Gieson staining methods. It bonds by electrostatic forces with the negatively charged macromolecules. By gradual increasing of the electrolyte concentration used to wash the bound dye, one can selectively identify neutral, sulphated, and phosphated mucopolysaccharides.
    The Van Gieson stain (Ira van Gieson, 1865-1913, an American bacteriologist) is specific for connective tissue (CT) elements. This combination permits you to distinguish two types of CT elements in the wall of this artery: the black strands are elastic fibers and the bright red material is the reinforcing collagen. As with other combined stains, it provides structural information that the single components alone can't; and complements the general structural stains such as H&E.

    Transmission electron microscopy, what is meant and what can you see.

     

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