Clearing

Question 1

1. clearing agents only
2. dealcoholizing agents only

Answer 1

1. glycerin, gum syrup, brun’s solution
2. chloroform, carbon tetrachloride

Question 2

Clearing in Embedding
1. done after ___ & before _____
2. agents (4)

Clearing in Mounting
1. done after ___ & before _____
2. agents (4)

Answer 2

Clearing in Embedding
1. after dehydration & before infiltration
2. xylene, toluene, dioxane and chloroform

Clearing in Mounting
1. after staining & before mounting
2. xylene, toluene, terpineol, carbol-xylene

Question 3

FACTORS OF CLEARING

1. agents w/ __ BP are readily replaced by paraffin (except chloroform)
2. higher viscosity = ___ penetration
3. does not affect the rate but affects the quality of cleared tissue

Answer 3

1. low BP
2. slow
3. Refractive Index

Question 4

Common Clearing Agents

1. most rapid; excellent clearing agent but tends to make tissues excessively hard & brittle (time)
   - turns milky when _____
2. substitute for xylene (time)
   - highly inflammable; carcinogenic&raquo_space; ___ (toxic to bm)
3. similar to xylene but doesn’t harden tissues nearly so much (time)
   - not carcinogenic but emits _____
4. for nervous tissues, lymph nodes & embryos (time)
   - cheaper alternative
5. recommended for cns, smooth muscles & skin (time)
   - susbstite
   - form crystals with
   - turns milky on ______

Answer 4

1. Xylene (15-30mins)
   - dehydration is not complete
2. Benzene (15-60mins)
   - aplastic anemia
3. Toluene (1-2hrs)
   - toxic fumes
4. Chloroform (6-24hrs)
   - Carbon Tetrachloride):
5. Cedarwood oil (2-3 days)
   - Terpineol
   - acetic alcohol fixatives
   - prolonged storage

Question 5

Other Clearing Agents
1. for embryos, insects and delicate specimen
- clears
2. slow; may be adulterated; removes aniline dyes
3. both dehydrating and clearing
4. for large pieces of tissues & embryonic materials
5. used in double embedding

Answer 5

1. Aniline Oil
   - 70% alcohol
2. Clove Oil
3. Dioxane
4. Amyl acetate
5. Methyl Benzoate/ Salicylate

Question 6

Other Clearing Agents
1. tissue is to be cleared directly from water (no de-
alcoholization, merely improves RI)
2. for materials that are difficult to clear
- thoroughly rinsed in ____
3. others (3)
4. Newer Clearing
Agents
- volatile oil found in citrus peels
- long chain aliphatic HC

Answer 6

1. Glycerin, Gum Syrup & Brun’s solution
2. Carbon Xylene
   - xylene
3. • oil of bergamot
   • phenol in alcohol
   • creosote
4. • Terpenes
   • Clearite