zulibimbamboom 3: Clearing (copy)

Clearing

process of removing the dehydrating agent from the tissue

Paraffin Wax

Clearing

What impregnation or infiltration agent should the sample dissolve with?

Canada Balsam

Clearing

What mounting medium should the sample dissolve with?

Alcohol

Clearing

Step 1: __ replaces water in all cells

Xylene

Clearing

Step 2: __ dissolves alcohol

Paraffin Wax

Clearing

Step 3: __displaces xylene

• specimen is ready to be embedded

serves to mix with alcohol and remove it from the tissue

Functions of the Clearing Agent

when used after alcohol dehydration

will make microscopic tissue preparation transparent

Functions of the Clearing Agent

when used after tissue section has been stained

will merely improve refractive index of the tissue (glycerin and gum syrup)

• no dealcoholization involved

Functions of the Clearing Agent

when the tissue is to be cleared directly from water

Alcohol

Characteristics of a Good Clearing Agent

be miscible with __

Paraffin Wax

Characteristics of a Good Clearing Agent

be miscible with and easily removed by __

transparent

Characteristics of a Good Clearing Agent

make tissues __

shrinkage, hardening

NOT Characteristics of a Good Clearing Agent

produce excessive __ and __

aniline dyes

NOT Characteristics of a Good Clearing Agent

dissolve out __

evaporate

NOT Characteristics of a Good Clearing Agent

__ quickly in a water bath

• boiling point

• viscosity

• prolonged exposure to clearing agent

Factors affecting Clearing

low

Factors affecting Clearing - Boiling Point

those with __ boiling point are more readily replaced by melted paraffin

penetration

Factors affecting Clearing - Viscosity

affects the speed of __ of the clearing agent

water

Factors affecting Clearing - Viscosity

To what liquid must the best clearing agent be closest to?

brittle

Factors affecting Clearing - Prolonged Exposure to Clearing Agent

causes tissue to become __

• type of tissue to be processed and the type of processing to be undertaken

• processor system to be used

• intended processing conditions such as temperature, vacuum, and pressure

• safety factors

• cost and convenience

• speedy removal of dehydrating agent

• ease of removal by molten paraffin wax

• minimal tissue damage

Choice of a clearing agent is dependent on 8 factors which are?

• xylene

• toluene

• benzene

• chloroform

• cedarwood oil

• aniline oil

• clove oil

• carbon tetrachloride

What are the commonly used clearing agents?

Xylene

What is the MOST commonly used clearing agent?

colorless

Xylene

What color does it exhibit?

0.5-1 hour

Xylene

What is its clearing time?

embedding, mounting

Xylene

It is used for the clearing of both __ and __ procedures

less than 24 hours

Xylene

Its routine histologic processing schedules last for?

<5 mm

Xylene

What is the thickness of the tissue block?

TRUE

TRUE OR FALSE

Xylene is the MOST rapid clearing agent.

transparent

Advantages of Xylene

makes tissue __

absolute alcohol, paraffin

Advantages of Xylene

miscible with __ and __

FALSE. Xylene does not extract out aniline dyes.

TRUE OR FALSE

Xylene EXTRACTS out aniline dyes.

mounting

Advantages of Xylene

for __ procedures

quickly

Advantages of Xylene

during embedding and impregnation, it evaporates __ in paraffin oven

TRUE

TRUE OR FALSE

Xylene is a cheap clearing agent.

TRUE

TRUE OR FALSE

Xylene is highly inflammable.

over 3 hours

Disadvantages of Xylene

makes tissue excessively hard if used __

nervous tissues, lymph nodes

Disadvantages of Xylene

not suitable for __ and __

subliming

Special Handling Procedures and Storage Requirements of Xylene

Keep container tightly closed to prevent xylene from __ and entering the atmosphere.

non-sparking

Special Handling Procedures and Storage Requirements of Xylene

Only __ tools may be used to handle xylene.

cool and dry area away from incompatible substances

• e.g. oxidizing agents, strong acids

Special Handling Procedures and Storage Requirements of Xylene

In what area must xylene be stored in?

flammable liquid storage cabinet

Special Handling Procedures and Storage Requirements of Xylene

In what type of cabinet must xylene be stored in?

TRUE

TRUE OR FALSE

Wash hands thoroughly after handling xylene, even if gloves were used.

contaminated clothing

Special Handling Procedures and Storage Requirements of Xylene

Remove __ and wash before reuse.

xylene or benzene

Toluene

Substitutes for __ or __ for clearing both during embedding and mounting processes

1-2 hours

Toluene

What is its clearing time?

absolute alcohol, paraffin

Advantages of Toluene

miscible with __ and __

FALSE. It acts RAPIDLY.

TRUE OF FALSE

Toluene acts SLOWLY.

over 24 hours

Advantages of Toluene

Does not make tissues excessively hard and brittle if left for __

slower

Disadvantages of Toluene

Is toluene faster or slower than xylene and benzene?

partially

Disadvantages of Toluene

Acidifies in a __ filled vessel

TRUE

TRUE OR FALSE

Toluene produces toxic fumes.

expensive

Disadvantages of Toluene

Toluene is more __ than xylene.

rapidly

Benzene

penetrates and clears tissues __

TRUE

TRUE OR FALSE

Benzene is rapid acting.

volatilizes

Advantages of Benzene

__ rapidly in paraffin oven

No. It does not make tissues hard and brittle.

Advantages of Benzene

Does benzene make tissues hard and brittle?

minimum

Advantages of Benzene

causes __ shrinkage

transparent

Advantages of Benzene

makes tissues __

Yes. It is highly inflammable.

Disadvantages of Benzene

Is benzene highly inflammable?

shrinkage

Disadvantages of Benzene

If left in benzene for a long time, considerable tissue __ is observed.

extremely toxic

Disadvantages of Benzene

excessive exposure may be __ to man

Aplastic Anemia

What occurs when the bone marrow fails and the cell production slows down and often stops?

• Supportive Therapy

• Curative Treatment

How is Aplastic Anemia treated?

• immunosuppressive treatment

• blood and marrow transplantation (BMT)

What are examples of curative treatment for aplastic anemia?

slower

Chloroform

When used for clearing in embedding process, it is __ than xylene

less

Chloroform

causes __ brittleness

1cm

Chloroform

used for thicker tissue blocks up to __

No. The tissues do not become translucent.

Chloroform

Do the tissues become translucent?

routine

Advantages of Chloroform

for __ work, 6-24 hours

absolute alcohol

Advantages of Chloroform

miscible with __

tough tissues for nervous tissues, lymph nodes, and embryos

• skin

• dibroid

• decalcified tissues

Advantages of Chloroform

causes minimum shrinkage and is for __ tissues

large specimens

Advantages of Chloroform

Is it used for large or small tissue specimens?

No. It is not flammable.

Advantages of Chloroform

Is it flammable?

liver

Disadvantages of Chloroform

toxic to the __

slow

Disadvantages of Chloroform

wax impregnation after chloroform is relatively __

No. It does not make tissues transparent.

Disadvantages of Chloroform

Does it make tissues transparent?

volatile

Disadvantages of Chloroform

not very __ in paraffin oven

vapor

Disadvantages of Chloroform

__ may attack rubber seal used in vacuum impregnating bath

complete

Disadvantages of Chloroform

__ clearing is difficult to evaluate

float

Disadvantages of Chloroform

tissues tend to __ in chloroform

quickly

Disadvantages of Chloroform

evaporates __ from a water bath

paraffin, celloidin

Cedarwood Oil

used to clear both __ and __sections during the embedding process

CNS tissues, cytological studies

Cedarwood Oil

recommended for __ and __

two

Cedarwood Oil

requires __ changes in clearing solution

2-3 days

Cedarwood Oil

What is its clearing time?

FALSE. It is very penetrating.

TRUE OR FALSE

Cedarwood Oil is NOT very penetrating.

95% alcohol

Advantages of Cedarwood Oil

miscible with __ alcohol, which it removes readily

5-6 days

Advantages of Cedarwood Oil

clears celloidin in __ days

minimal

Advantages of Cedarwood Oil

causes __ shrinkage and hardening

indefinitely

Advantages of Cedarwood Oil

tissue may be left __ without causing considerable damage and distortion

transparent

Advantages of Cedarwood Oil

makes tissues __

cutting

Advantages of Cedarwood Oil

improves __ of sections

slow

Disadvantages of Cedarwood Oil

extremely __

hard

Disadvantages of Cedarwood Oil

__ to be eliminated from tissues in paraffin bath

FALSE. The quality produced is NOT always uniform and good.

TRUE OR FALSE

The quality produced when using cedarwood oil is ALWAYS uniform and good.

milky

Disadvantages of Cedarwood Oil

becomes __ upon prolonged storage

crystals

Disadvantages of Cedarwood Oil

previously used to clear acetic-alcohol fixed tissues may produce __

No. It is very expensive.

Disadvantages of Cedarwood Oil

Is it cheap?