HISTOPATHOLOGY LECTURE (Topic 9) - ADHESIVES, MOUNTING, AND LABELING

After sections are floated on a water bath.

When is flashing out performed?

10°C lower than the melting point of wax.

What should the water bath temperature be during flashing out?

Slide is immersed in the water bath and the section is fished out and drained.

How is the section collected during flashing out?

Correct positioning of tissue section/ribbon on the slide.

What is orientation in histopathology?

Remove residual wax and firmly attach tissue to the slide.

What is the main goal of deparaffinization and drying out?

56°C–60°C for 2 hours

What temperature and duration are used in a wax oven?

Controlled melting and removal of paraffin.

Why is a wax oven used?

37°C overnight

What temperature is used in incubator drying?

Gentler and gradual drying method.

Why is incubator drying useful?

45°C–55°C for 30–45 minutes

What temperature is used in hot plate drying?

Quick deparaffinization for routine cases

Why is hot plate drying commonly used?

Rapid drying.

What is the purpose of alcohol lamp/Bunsen flame drying?

Avoid overheating and tissue damage.

What precaution must be observed with flame drying?

37°C for at least 24 hours

How are delicate tissues dried?

Prevent splitting or cracking.

Why are delicate tissues dried slowly?

50°C–55°C for 20–30 minutes.

What temperature is used in blower-type electric slide dryers?

Controlled airflow and temperature.

What does blower-type drying use?

Prevent washing off of tissue sections during staining.

What is the main purpose of adhesives?

On glass slides

Where are adhesives applied?

No.

Are adhesives necessary for routine staining?

When sections are exposed to acids and alkalis during staining.

When are adhesives essential?

Maintain integrity of tissue sections during staining

What is another role of adhesives?

When clean grease-free slides and properly dried sections are used

When may adhesives not be necessary?

Sections float off during staining

What may happen if sections are poorly adhered?

Cryostat sections for immunocytochemistry.

Which urgent procedure commonly requires adhesives?

Central nervous system tissue

Which nervous tissue commonly needs adhesives?

Tissues containing blood clots

What blood-related specimen often requires adhesives?

Decalcified tissues

Which processed tissues often require adhesives?

When sections are exposed to high temperatures

When else are adhesives important?

Mayer’s egg albumin, dried albumin, gelatin, gelatin-formaldehyde, Poly-L-Lysine, APES

What are common slide adhesives?

Mayer’s Egg Albumin

What is the most commonly used adhesive?

Egg white, glycerin, and thymol.

What are the components of Mayer’s Egg Albumin?

50 mL

What amount of egg white is used?

50 mL.

What amount of glycerin is used?

Prevent mold growth.

Why is thymol added?

Smeared on clean glass slides before section orientation

How is Mayer’s Egg Albumin applied?

Convenient, easy to make, and inexpensive

What is the advantage of Mayer’s Egg Albumin?

Retains stain and produces dirty background.

What is its disadvantage?

Dried albumin + NaCl + thymol.

What are the components of dried albumin adhesive?

In 70% alcohol until staining

How are slides stored after dried albumin application?

Gelatin + glycerol + phenol.

What are the components of 1% gelatin adhesive?

Water bath during flotation.

Where is 1% gelatin commonly added?

Gelatin + formaldehyde.

What are the components of gelatin-formaldehyde adhesive?

Air dried at 37°C for 1 hour or overnight.

How are gelatin-formaldehyde coated slides dried?

0.01%

What concentration is Poly-L-Lysine diluted to?

Immunohistochemistry

What field commonly uses Poly-L-Lysine?

3-aminopropyltriethoxysilane.

What does APES stand for?

Cytology

In which field is APES especially useful?

Cytospin preparations of proteinaceous or bloody material.

What preparations especially use APES?

APES

What is considered the best section adhesive?

Long storage life.

What is an advantage of APES-coated slides?

Reduces differences in light refraction

Why is mounting necessary?

Reduced microscopic detail

What may happen if stained sections are unmounted?

Close to glass and tissue

What RI should mounting media possess?

Image distortion

What does mounting help prevent?

Contrast and transparency

What does refractive index influence?

Greater transparency

What does a higher RI provide?

Protect specimen, improve transparency, reduce oxidation, preserve permanently, ease handling.

What are the major functions of mounting?

Center of the slide

Where is mounting medium first placed?

Gradually inclined downward onto the mountant.

How is the coverslip applied?

Gentle pressure on the coverslip

What spreads the mountant through the section?

12–24 hours at 37°C

How long are mounted slides incubated?

Harden the mountant

Why are mounted slides incubated?

No

Should immersion oil be used on uncovered slides?

Carefully and horizontally

How should slides be handled if viewed urgently?

No, not for 2 days

Should mounted slides be stored vertically immediately?

Fine cloth moistened with xylene

How is excess mountant removed?

Shrinkage and cracking.

What may excessive blotting cause?

Soak coverslip in xylene

How can remounting be performed?

Coverslip misalignment and bubbles

What may insufficient mountant cause?

Mounting needle or gentle pressure.

How are bubbles removed?

Heating at 50°C for 2 hours.

How can mountant setting be accelerated?

Close to glass (1.518)

What RI should good mounting medium have?

Colorless and transparent.

What appearance should mounting medium have?

Xylene and toluene

With what solvents should mountants mix freely?

Quickly without becoming sticky

How should mountants harden?

Physical and chemical damage

What should mounting medium protect against?

Yes

Should mountants resist contamination?

No

Should mountants cause tissue shrinkage?

No

Should mountants affect staining?

No

Should mountants crystallize or crack?

Stable permanent section

What should a properly set mountant produce?

Sealing margins of the coverslip

What is ringing?

Prevent leakage, evaporation, sticking, and coverslip movement

What are the functions of ringing?

Paraffin and powdered colophonium resin

What is Krong cement composed of?

Cellulose adhesive

What is Durofix?

Aqueous and non-aqueous/resinous.

What are the two major mounting media types?

Water-based substances like glycerol and sugar polymers.

What is the composition of aqueous mountants?

1.34–1.41

What RI range do aqueous mountants have?

Yes

Are aqueous mountants water-soluble?

No

Do aqueous mountants require dehydration and clearing?

Temporary mounting and water-soluble stains

What are aqueous mountants mainly used for?

Water, glycerin, glycerin jelly, Farrant’s medium, Apathy’s medium, Brun’s fluid.

What are examples of aqueous mountants?

1.33

What is the RI of water?

Temporary mounting

What is water mainly used for?

Evaporates easily

What is a disadvantage of water mountant?

1.46.

What is the RI of glycerin?

Preservative and semi-permanent medium.

What are the uses of glycerin?

Fat stains

What stains commonly use glycerin?

Inexpensive and non-poisonous

What are advantages of glycerin?