CLEARING Flashcards
REMEMBER!
Clearing is also known as DEALCOHOLIZATION
The process wherein ALCOHOL or DEHYDRATING FLUID IS REMOVED from the tissue and replaced with intermediate solvent that is fully miscible with both ethanol and paraffin wax
CLEARING
Clearing agent should be at least _______ the volume of the tissue:
10 TIMES
Characteristics of a good clearing agent
- Miscible with alcohol
- Miscible with paraffin wax
- Should not produce excessive shrinkage
- Should not dissolve out aniline dyes
- Should not evaporate quickly in a water bath
- Makes tissues transparent
CLEARING AGENTS:
- Xylene (xylol)
- Chloroform
- Benzene
- Toluene
- Cedarwood oil
- Aniline oil
- Methyl benzoate and methyl salicylate
- Clove oil
- Carbon tetrachloride
Colorless, MOST COMMONLY USED CLEARING AGENT; MOST RAPID CLEARING AGENT, suitable for URGENT BIOPSIES which it clears within 15 to 30 minutes
XYLENE (XYLOL)
Xylene becomes milky when an _________ tissue is immersed in it
INCOMPLETE DEHYDRATION
Xylene is miscible with:
alcohol and paraffin wax
Used for TOUGH TISSUES (skin, fibrinoid, decalcified tissues), nervoues tissues, lymph nodes and embryos because it causes minimum shrinkage and hardening of tissues; TOXIC TO LIVER upon prolonged exposure and it DOES NOT MAKE THE TISSUE TRANSPARENT
CHLOROFORM
RAPID ACTING (15 TO 60 MINUTES); Excessive exposure to this clearing agent may be extremely toxic and may become carcinogenic or it may damage the bone marrow resulting in APLASTIC ANEMIA
BENZENE
Used as a SUBSTITUTE FOR XYELENE OR BENZENE for clearing both during embedding and mounting processes
TOLUENE
Recommended for CENTRAL NERVOUS SYSTEM (CNS) tissues and CYTOLOGICAL STUDIES, particularly of smooth muscles and skin
CEDARWOOD OIL
This clearing agent becomes milky upon prolonged storage and should be filtered before use
CEDARWOOD OIL
Recommended clearing agent for EMBRYO and fine, VERY DELICATE SPECIMENS due to its ability to clear 70% alcohol without excessive tissue shrinkage and hardening
ANILINE OIL
Slow-acting clearing agents that can be used when COUBLE EMBEDDING TECHNIQUES are required
METHYL BENZOATE and METHYL SALICYLATE
