Special stains

SPECIAL STAINS

1. Special Stains

2. Hematoxylin and Eosin Staining Principle Hematoxylin , being a basic dye, has an affinity for the nucleic acids in the cell nucleus Result After staining nuclei appear basophilic that is bluish to purple in color Principle Eosin is an acidic dye with an affinity for cytoplasm and membrane of the cell Result After staining cytoplasm appear eosinophilic that is pinkish in color

3. Mucin stains contin … PAS ( peroidic acid-Schiff) Uses: Stains glycogen, mucins, mucoprotein , glycoprotein and fungi and useful for outlining tissue structures--basement membranes, capsules, blood vessels To differentiate between glycogen from mucin, tissue can be pre-digested with diastase/amylase , the glycogen will be removed but not mucins Fungus; further confirmed by fungal stains Result : Positives magenta color

4. Mucin stains Mucicarmine Uses: Very specific for epithelial mucins, but it is very insensitive, so not very useful Result: positive shows red color Alcian blue Uses: pH of this stain can be adjusted to give more specificity. Mucins of epithelial cells containing sialic acid positive at pH 2.5 and adenocarcinoma is positive at pH 1 Result: Positive shows blue color

5. Melanin stain - Fontana-Masson Normal melanin granules brownish in color Principle: Fontana-Masson method relies upon the melanin granules to reduce ammonical silver nitrate thus giving blackish staining (but argentaffin , chromaffin, and some lipochrome pigments also stain black) Schmorl's method helps in differentiating melanin by using the reducing properties of melanin to stain granules blue-green Normal

6. Lipochrome ( lipofucsin ) pigments Lipochrome ( wear-and-tear pigments) products of intracellular breakdown from oxidation of lipids and lipoproteins Found most commonly in heart, liver, CNS, and adrenal cortex (zona reticularis ) Lipochrome can be stained by; - Sudan black B - Schmorl's methods

7. Iron (hemosiderin) stain Perl's iron stain Classic method for demonstrating iron in tissues Principle: Tissue section treated with dilute HCL to release ferric ions from binding proteins which react with potassium ferrocyanide to produce an insoluble blue compound (the Prussian blue reaction ) Hemosiderin, liver, iron stain.

8. Fat stains O il red O (ORO) is a rapid and simple stain, can identify neutral lipids and fatty acids in smears and tissues It is useful in identifying fat emboli in lung tissue or clot sections of peripheral blood Fresh smears or cryostat sections of tissue are necessary because fixatives containing alcohols, or routine tissue processing with clearing, will remove lipids Oil red O stain of fat emboli in lung

9. Romanowsky-type" stains Giemsa stain; can be helpful for identifying components in a variety of tissues Wright-Giemsa stain; utilized to stain peripheral blood smears Methylene blue and Toluidine blue dyes; Have property of metachromasia , this means that a tissue component stains a different color than the dye itself For example, mast cell graules , cartilage, mucin, and amyloid will stain purple and not blue, which is helpful in identifying these components C ytoplasmic granules of mast cells in the upper dermis stain metachromatically , giving the intense purple color

10. AFB (acid fast bacilli) stain The most commonly used method is the Ziehl-Neelsen method which uses carbol-fuchsin to stain the lipid walls of acid fast organisms such as  M. tuberculosis A modification of this stain is the Fite stain used to stain   M. leprae   bacilli Other acid fast things includes cryptosporidium, isospora , and the hooklets of cysticerci

11. Gomori M ethenamine S ilver (GMS) stain Used to stain fungi and Pneumocystis carinii C ell walls of these organisms are stained, so the organisms are outlined by the brown to black stain Cryptococcus neoformans Candida albicans

12. Connective tissue stains Masson Trichrome stain Helps to highlight the supporting collagenous stroma in normal structures , such as connective tissue capsules of organs, the lamina propria of gastrointestinal tract, and the bronchovascular structures in lung and in pathological conditions Result: gives blue color to fibrocollagenous tissue A- Chronic hepatitis B- Cirrhosis of liver

13. Stains for Calcium Only calcium that is bound to an anion (such as PO4 or CO3) can be demonstrated as blue color on H&E stain VonKossa stain demonstrates phosphates and carbonates, usually present along with calcium giving black color and is most useful as in bone Azan stain can be used to differentiate osteoid from mineralized bone

14. Congo red stain Used to demonstrate amyloid deposits in a tissue Result: Amyloid material red in color Positive for amyloid stain Medullary carcinoma thyroid

15. Assignment Q1. Name the components of the cell which appear basophilic and eosinophilic after staining with hematoxylin and eosin, and also give reason. Q2. G astric biopsy shows signet ring cell carcinoma and superadded candida infection. a. Name the special stain to demonstrate signet ring cell carcinoma b. Which stain can be helpful for the identification of candida albicans ? Q3. Liver biopsy of a thalassemia patient is submitted to check the iron deposits. Which stain can be used for this purpose and what will be result of staining? Q4. To assess the stage of fibrosis in a liver biopsy from a patient of chronic hepatitis ; which special stain you will apply on a liver biopsy section and what will be the result of staining?

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