Staining Techniques Flashcards
What does Hematoxylin stain?
Hematoxylin is positively charged/basophilic and will stain negative parts of the cells blue (nucleus, nucleous, RER)
What does Eosin stain?
Eosin is negatively charged/acidophilic and will stain positive parts of the cell pink/red (cytoplasmic filaments, intracellular membranous components, most proteins)
What is an acidophilic stain?
Reacts with cationic (+) groups
What is a basophilic stain?
Reacts with anionic (-) groups
What does Trichrome stain?
Used to distinguish between collagen and muscle
Mallory vs. Masson Trichrome staining
Mallory stains collagen sky blue vs Masson stains collagen greenish-blue
Elastic stain plus H&E
Used to stain elastic fibers which stain black/purple. Ex Aldehyde fuchsin is an elastic stain
What does silver stain identify?
Reticular fibers are stained black with silver stain in lymph nodes and spleen
What does Periodic Acid-Schiff (PAS) stain?
Carbohydrates, which are usually washed out by preparation, are stained with carbohydrates (mucus) and basement membrane a red-ish color
What does Alcian blue stain?
Acidic mucus - carbohydrate
What does oil red O stain?
Lipids - fixation with formalin removed lipids, but staining with oil red O will stain lipid droplets as red droplets, as opposed to H&E in which you assume the presence of the lipid in empty blank spheres
What does osmium tetroxide stain?
Lipids - staining them dark brown/black, such as myelin sheaths, stains by crosslinking lipids
Phase-contrast microscopy
Used for visualizing unstained, unpigmented living cells
Darkfield microscopy
Used to increase the contrast of small objects in unstained specimens
Polarizing microscopy
Filter blocks unrotated light from reaching the eyepiece, such that only well-ordered structures are visible - such as cystalline or paracrystalline array - MTs, collagen fibers
Fluorescence microscope
Detects molecules with fluorescence that emit visible light when exposed to specific UV wavelengths
Confocal scanning microscope
produces an optical section of unsectioned specimen, can see different layers of whole object
Enzyme Histochemistry
Product of the enzyme reaction is precipitated, and the product is visualized rather than the enzyme
Immunohistochemistry
Used to detect specific proteins of interest, requires antibodies
Autoradiography
Used to localize newly synthesized macromolecules in cell and tissue sections through incorporation of tagged molecule, usually Tritium H3
