INFILTRATION Flashcards
What is infiltration?
- Removal of clearing agents from the tissue
- Replacing the clearing agent in a supportive medium
This is the process of completely filling the tissue spaces with a medium with a firm consistency.
Impregnation
What would be filled in the impregnation process?
Natural cavities
Spaces
Interstices
Under care and selection of waxes, what should be the volume of the medium?
25X tissue volume
Under care and selection of waxes, what should be the melting point?
56C
This type of tissue requires a higher melting point
Hard tissues
What is the type of microtome used under infiltration and impregnation?
Fixed-knife microtome
What type of knife is used under fixed-knife microtomes?
Heavier knives
This infiltrates support and encloses tissue specimens which provide structural integrity and shape of the tissue.
Embedding media
This encloses the tissue specimens for complete protection from the cutting of the tissues without damaging the tissue samples.
Embedding media
What should be the characteristic of an embedding media?
Must be capable of being converted readily from liquid to solid form.
What is commonly used in crystallization?
Paraffin and carbowax
Paraffin and carbowax are used in?
Crystallization
What is used in evaporation of the solvent?
Celloidin
Celloidin is used in?
Evaporation of the solvent
What is used in polymerization?
Plastics
Plastics are used in?
Polymerization
What are the mechanisms of solidification?
Crystallization
Evaporation
Polymerization
Enumerate the types of embedding
Paraffin embedding
This type of embedding is the most commonly used in routine tissue processing, and the best embedding medium.
Paraffin embedding
Paraffin embedding shrinks about _______ on cooling.
10%
Under paraffin embedding, what is the melting point for normal routine work?
56-58C
The paraffin oven that would be used under paraffin embedding should be set at what temperature?
2-5C higher than the melting point of paraffin wax.
What are the methods of paraffin impregnation?
Manual processing
Automatic processing
Vacuum processing
How many changes are done under manual processing? Include the temperature.
4 changes at 2-5C higher than the melting point of the wax
Under fixation of manual processing, how many hours is needed for 10% NBF?
24 HOURS
Under clearing of manual processing, how many hours should it take for Xylene or Toluene?
1 hour
Under impregnation and Embedding of manual processing, how long should it take for the Paraffin wax?
Impregnation : 15 minutes
Embedding : 3 hours
How often do you change under automatic processing? Include the time.
2-3 changes for at least 3C higher than the melting point of the wax.
If you are using a wax bath, what should be the temperature?
3C higher than the melting point
Under automatic processing how long is the processing time of 10%NBF and 70% alcohol and Chlorform?
2 hours
How long is the processing time of Xylene of Toluene under automatic processing?
1 hour
How long is the processing time of Benzene 1 and 2 under automatic processing?
30 minutes (1)
1 hour (2)
What is the negative atmospheric pressure of Vacuum processing?
400-500mmHg
How often do you change in vacuum processing? Include the time
3 changes at 2-4C above the melting point of wax.
Where do you apply vacuum processing?
Urgent biopsies
Dense biopsies
Delicate biopsies
Fibrous biopsies
Vacuum processing is composed of?
Flat-bottom heavy brass chamber
2 screw valves
Vacuum processing has 2 valves, what is the function of each valve?
1st : readmission of air
2nd: Connected to a tube and a suction pump
One consideration of the method of paraffin impregnation is:
Paraffin ax must be _____: used only ______.
Pure: Twice
At what temperature will water remove be removed by heating paraffin?
100-105C
What are the substitutes for paraffin wax?
Paraplast
Ester wax
Water soluble waxes
What is the melting point of paraplast?
56-57C
More elastic and resilient than regular paraffin wax.
It can withstand or it can handle more than the
paraffin wax. It doesn’t crumble during
microtomy or cutting of tissues
Paraplast
Better ribboning with ease
Doesn’t require cooling
Paraplast
What are the type of paraplast?
Embeddol
Bioloid
Tissue mat
Synthetic wax used as a substitute for paraplast
Less brittle than paraplast (during sectioning)
Embeddol
What is the melting point of embeddol?
26-58C
Semisynthetic wax that is used in impregnating and
embedding eye samples
Bioloid
Contains rubber (from paraffin)
Tissue mat
What is the melting point of ester wax?
To which reagent is fixative soluble?
46-48C
75 ethyl alcohol
Lower melting point but harder than paraffin
Ester wax
What is the melting point of water soluble waxes?
38-42C or 45-56C
What is the composition of Water soluble waxes?
Polyethylene glycol
Does not require dehydration and clearing
Suitable for histochemical and enzyme studies
Carbowax
What is the common advantage of Carbowax?
It does not remove neutral fats and lipids
At what temperature is blocking done at carboxy processing?
50C
Avoid overheating in carboxy processing because it will?
Crumby blocks
One precaution when doing carboxy processing is that it is highly soluble in water or?
Hygroscopic
Carbowax cannot float in water because it is hygroscopic, therefore what would be the remedy?
Add soap or 10% polyethylene glycol 900 ml in water
bath
Use floating solutions
What are the floating solutions used in carboxy processing?
Pearse solution
Blank and Mc Carthy solution
Mixture of formalin, Diethyl glycol, Distilled
water
Pearse solution
Containing gelatin and potassium chromate
BLANK and MC CARTHY SOLUTION