SPECIAL STAINS. PART 7 Flashcards
OIL RED O STAIN
What is the purpose of oil red O stain
Oil Red O (‘ORO’) is used to demonstrate
the presence of fat or lipids in fresh,
frozen tissue sections
Why is oil red o not recognized as a true special stain
because it can’t form bonds with lipid components.
( It is actually a pigment that functions as an oil-soluble colorant)
why are lipids not retained in tissues
During tissue processing xylene and alcohol are used to dehydrate and clear the tissue and unfortunately these solvents can dissolve and remove the lipids from the tissue that is why lipids are not retained in tissues.
Why is it that lipids are suspected by their absence. Explain
when the H&E stain is applied to the tissue lipids do not take up the stain as a result areas where areas lipids were present remain unstained appealing as holes in the stained tissue. therefor the absence of staining indicates the likely precence of lipids.
So how are lipids suspected in a tissue
They are suspected by their absence
Explain the general principle of the stain
The basis for staining lipids with an oil-soluble dye lies in its increased solubility in fatty substances as opposed to the dye solvents that are used in routine tissue processing.
The choice of solvent for this reaction is also critical, since it must be able to extract excess dye without dissolving the lipid to be stained- propylene glycol is the preferred solvent for this technique.
The end result is that fat and lipids in tissue sections stain bright red, and nuclei stain blue. Although other stains are available to help detect the presence of lipids in
tissues, the intensity of its red coloration makes ORO the preferred choice.
How is oil red o used in diagnostic lab. mention 3
- It is also useful to identify tumors, such as lipomas and liposarcomas that arise from fat cells
- Fractures or crush injuries in fatty areas of the body can release fat into the bloodstream, resulting in fat emboli (Fat emboli are small particles of fat that enter the circulatory system through veins or arteries) . These emboli can be fatal, and they are identified using oil red o staining.
- Deposits of fat may also appear in the liver and kidney in a variety of pathological conditions
How is oil red o used in forensics labs
As a reagent for fingerprint development.
(n 2004, Alex Beaudoin discovered a technique using ORO as a reagent to enhance latent prints produced by the lipids found in fingerprints)
