![]() The following table contains a protocol with a simple regressive stain that provides a nice balance of nuclear and cytoplasmic stains. In combination, these components make up the standard stain most used in the histology laboratory. In most cases, though, labs typically add this step to ensure appropriate bluing. In some locations, the tap water contains enough minerals so that the pH causes the water to be basic enough to allow for the bluing of nuclei without the need for a bluing specific reagent. These slightly basic solutions chemically alter the dye to produce this color change. Part of this trend is due to the use of automated staining, which must accommodate the movement of the robotic arm in addition to the time spent in the reagent.īluing reagents, such as Scott's Tap Water, are used to change the hematoxylin from red to the traditional blue color we expect. While hydrochloric acid (HCl) has historically been the standard, milder acids are being used to provide gentler dye removal. In the case of hematoxylin, hydrochloric acid (for rapid differentiation) and acetic acid (for slower, more controlled differentiation) are most commonly used. The differentiation of stains allows for the ability to selectively remove stain from tissues to the taste of the viewer. One of the best known is Weigert's, which is used in the Verhoeff-Van Gieson stain, shown in the image. This is because they can demonstrate more tissue structures than alum hematoxylins, such as myelin and elastin fibers. The hematoxylins that use iron salts as a mordant are typically used in special stains. Mucin and even adhesives used on the slide may become heavily contaminated with Gills. However, the nature of Gills is such that extra-nuclear staining may occur. Because it is made with water and ethylene glycol, autoxidation of the stain is typically prevented over months, making it more stable than Harris hematoxylin. It may be used as a progressive or regressive stain and is available in different concentrations. Gill's hematoxylin is an alum hematoxylin. One challenge when using Harris is that it is best differentiated with a mild acid, as opposed to the more commonly used hydrochloric acid-based differentiators. The staining tends to provide clear nuclear detail. Harris hematoxylin is another commonly used alum hematoxylin that may be used for progressive staining of cytology specimens but can also be used for either progressive or regressive staining in histology. For these applications, Mayer's is used to stain the nuclei and then blued without the use of a differentiator. It is often used as a nuclear counterstain for special stains and immunohistochemistry. Mayer's hematoxylin is an alum hematoxylin, a commonly used stain that may be employed for both progressive and regressive stains. ![]() This mordant causes the nuclei to be red in color, which is then changed to the more familiar blue color when the sample is later rinsed with a weakly basic solution. The most common mordant used in routine histology is aluminum ammonium sulfate (alum). ![]() The type of mordant also influences the final color of the stained components. This aids the bonding of the hematin to the anionic tissue component, which is most commonly chromatin. Mordants strengthen the positive ionic charge of the hematin. ![]() Hematoxylins are typically classified by the mordant used before staining.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |