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MTAP 2 SPECIFICS > Dehydrating and clearing agents > Flashcards

Dehydrating and clearing agents Flashcards

1
Q

For routine dehydration of tissues
Best dehydrating agent - fast acting
Not poisonous
Not expensive

A

Ethyl Alcohol

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2
Q

Toxic dehydrating agent
Primarily employed for blood and tissue films and for smear preparation

A

Methyl Alcohol

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3
Q

This dehydrating agent is utilized in PLANT and ANIMAL microtechnique
Slow dehydrating agent
Producing less shrinkage and hardening than ethyl alcohol
Recommend for tissue which do not require rapid processing

A

Butyl Alcohol

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4
Q

Routine dehydration process

A

70% alcohol - 6 hours
95% alcohol - 12 hours
100% alcohol - 2 hours
100% alcohol - 1 hour
100% alcohol - 1hour

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5
Q

Dehydration of tissue NOT more than 4mm thick

A

70% Ethanol -15 min
90% ethanol - 15 mins
100% Ethanol - 15 mins
100% ethanol - 15 mins
100% ethanol - 30 mins
100% Ethanol -45 mins

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6
Q

A cheap, rapid acting dehydrating agent
Dehydrates in 1/2 to 2 hours
More miscible with epoxy resins than alcohol
20:1 ratio (Fixative)
Clear, Colorless highly flammable and extremely volatile fluid
Rapid in action but penetrates tissues poorly and causes brittleness in tissues that are prolonged dehydrated
Most lipids are removed
Produces considerable tissue shrinkage
NOT RECOMMENDED for routine dehydration purposes

A

Acetone

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7
Q

Excellent dehydrating and CLEARING agent
Produces less tissue shrinkage
Tissues can be left for long periods of time w/o affecting the consistency or staining properties of the specimen
Tissue sections dehydration with this dehydrating agent tends to ribbon POORLY
EXPENSIVE and extremely dangerous (Vapor is toxic)
Formed peroxide may EXPLODE upon air exposure

A

Dioxane (Diethyl Dioxide)

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8
Q

Dehydrates rapidly
The tissue may be transferred from water or normal saline directly to cellosolve and stored in it for months w/o producing hardening or distortion

Caution: Ethylene glycol ether is combustible at 110F to 120F and is toxic

Propylene based glycol ether should be used instead

A

Cellosive (Ethylene glycol monoethyl ether)

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9
Q

Removes water
Produces very little distortion and hardening of tissues
Soluble in alcohol, water, ether, benzene, chloroform acetone, and xylene
Used to dehydrate SECTIONS AND SMEARS

A

Triethyl Phosphate

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10
Q

BOTH DEHYDRATES and CLEARS tissues since it is miscible in water and paraffin
Can be used for demixing, clearing, and dehydration paraffin sections before and after staining
Causes less shrinkage and EASIER cutting of sections with FEWER artefacts
Does NOT dissolve aniline dyes
TOXIC if INGESTED or INHALED
Vapors causes nausea, dizziness, headache, and anesthesia

A

Tetrahydrofuran

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11
Q

Added to each 95T ethanol bats as part of dehydration process
Acts as a softener for hard tissues

A

4% Phenol

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12
Q

Dehydrating agent for Electron microscopy
Accompanied by PROPYLENE OXIDE as a transition fluid
Along with propylene oxide, this solvent have some undesirable propery

A

Ethanol

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13
Q

A good substitute for propylene
Non-carcinogenic, less toxic, and not as flammable as propylene oxide
Excellent dehydrating agent

A

Acetonitrile

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14
Q

Colorless clearing agent that is MOST COMMONLY used ⭐

Most rapid clearing agent, suitable for urgent biopsies

Clearing time is 1/2 hour to 1 hour

Makes tissue transparent

Does not extract aniline dye

Can be used for Celloidin sections because it does NOT dissolve celloidin

NOT suitable for nervous tissue and lymph nodes

CHEAP

A

Xylene

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15
Q

May be used as a SUBSTITUTE OR ALTERNATIVE ONLY for xylene or benzene ⭐

Clearing time is 1 - 2 hours

Acts fairly rapidly and is recommended for routine purpose

Tissues do not become excessively hard and brittle even if left for 24 hours

NOT carcinogenic

SLOWER than xylene and benzene
EXPENSIVE

A

Toluene

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16
Q

Preferred as a clearing agent in the embedding process of tissues because it penetrates and clears tissues rapidly

Clearing time is 15 to 60 minutes

Does not make tissues hard and brittle but it causes MINIMUM SHRINKAGE

Makes tissues transparent

FLAMMABLE

TISSHUE SHRINKAGE may be OBSERVED if left for a long time

Excessive exposure is TOXIC and CARCINOGENIC to human

May damage the bone marrow resulting in APLASTIC ANEMIA ⭐

A

Benzene

17
Q

Slower in action than xylene but causes less brittleness

Suitable for LARGE TISSUE SPECIMENS. Thicker blocks can be processed

Clearing time 6-24 hours

Recommended for NERVOUS TISSUES, LYMPH NODES, and EMBRYOS ⭐

NOT FLAMMABLE

Relatively toxic to the LIVER after prolonged inhalataion

Wax impregnation after this clearing agent is relatively slow

DOES NOT make tissue transparent

Difficult to REMOVE from paraffin section because it is NOT very volatile

Complete clearing is difficult to evaluate

A

Chloroform

18
Q

Advantages and Disadvantages are the same with chloroform ⭐

Produces CONSIDERABLE tissue HARDENING and DANGEROUS to inhale on prolonged exposure due to its highly toxic effects

A

Carbon tetrachloride

19
Q

Used to clear both PARAFFIN and CELLOIDIN sections during embedding process

Recommended for CNS tissues, and Cytological studies
CCC = _____ , CNS, Cytological

Very penetrating agent

Becomes MILKY upon prolonged storage and should be filtered before use ⭐

VERY EXPENSIVE

Extremely slow clearing agent, not for routine purposes

Clearing time is 2-3 days
Celloidin clearing is 5-6 days

A

Cedarwood oil

20
Q

Not normally utilized as a clearing agent

Recommended for clearing embryos, INSECTS, and VERY DELICATE SPECIMENS due to its ability to clear 70% ALCOHOL without excessive tissue shrinkage and hardening ⭐

A

Aniline oil

21
Q

Causes MINIMUM shrinkage of tissues

Its quality is not guaranteed due to its tendency to become ADULTERATED ⭐

Wax impregnation after clearing with this clearing agent is SLOW and DIFFICULT

Tissues become BRITTLE, aniline dyes are REMOVED and celloidin is DISSOLVED

EXPENSIVE and UNSUITABLE for routine clearing purposes

A

Clove oil

22
Q

Slow-acting clearing agents that can be used when DOUBLE EMBEDDING techniques are required ⭐

OIL OF WINTERGREEN

A

Methyl benzoate and Methyl Salicylate

23
Q

For frozen section

No de-alcoholization is involved in this process

A

Glycerin and gum syrup

MTAP 2 SPECIFICS (6 decks)

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