HISTOPATH DEHYDRATION Flashcards
CHARACTERISTICS OF IDEAL DEHYDRATING AGENT
Dehydrate rapidly w/o producing shrinkage
Evaporate very fast
Dehydrate fatty tissues
Should not harden tissue excessively
Should not remove stains
Should not be toxic to the body
Should not be fire hazard
Commonly used Dehydrating agents
Alcohol
Acetone
Dioxane 4-cellosolve
Triethyl phosphate
Tetrahydrofuran
For routine dehydration of tissues
Clear, colorless, flammable fluid
Best dehydrating agent (fast acting, mixes with water and many organic solvents, penetrates tissue easily, not poisonous, not very expensive)
ETHYL ALCOHOL
Toxic dehydrating agent
For blood and tissue films
For smear preparations
Methyl alcohol
Utilized in plant and animal micro-techniques
Slow dehydrating agent
Produces less shrinkage of tissue and hardening
Recommended for tissues not requiring rapid processing
BUTYL ALCOHOL
Harden only the surface of the tissue while the deeper parts are not completely penetrated
Generally smaller and more delicate tissues require lower concentrations
(below 70%) tends to macerate the tissue
37 Degrees celsius will hasten dehydration time
Concentrated/95% Alcohols
Cheap, rapid-acting dehydrating agent
For urgent biopsies
Dehydrates ½ to 2 hours
Clear, colorless fluid that mixes with water, ethanol and most organic solvents
Highly flammable, extreme volatility
Not recommended for routine dehydration
ACETONE
Excellent dehydrating and clearing agent
Miscible with water, meled paraffin,alcohol and xylol
Less tissue shrinkage
Tissue can be left for longer period
Expensive, dangerous (vapor is toxic in man)
Shld not be recycled, it create explosive peroxides
Dioxane (Diethylene Dioxide)
Dehydrate rapidly
Tissue maybe transferred from water or NSS directly to cellosolve and stored for months w/o hardening
Combustible at 110-120 farenheit
Toxic by inhalation, contact and ingestion
The reproductive, fetal, urinary and blood systems are vulnerable to their side effects
Cellosolve (Ethylene glycol monoethyl ether)
Removes water
Produces very little distortion and hardening
Soluble in alcohol, water, ether, benzene, chloroform, acetone and xylene
Dehydrate sections and smears ff certain stains
Produces minimum shrinkage
Triethyl phosphate
Dehydrate and clears
Miscible with water and paraffin
Dissolves fats
Miscible with lower alcohols, ether, chloroform, acetone, benzene and xylene
Toxic if ingested and inhaled
Causes nausea, dizziness, headache and anesthesia
Tetrahydrofuran (THF)
in THF
Eye and skin irritant
Done in well ventilated room
No way to protect the skin from irritation
Additives to Dehydrating Agents
Addition of 4% Phenol to 95% Ethanol, it acts as a softener for hard tissues such as tendon, nail, or dense fibrous tissue
Hard tissues can be immersed in a glycerol/alcohol mixture or in Molliflex
