41-68 Flashcards
Usual thickness of tissue sections for routine histologic procedures
4-6 u
Process of cutting the tissue into thin slices
Sectioning
Clearance angle when sectioning
0-15degrees
Temp of Water bath used for flotation
45-50’C (10’C lower than the melting point of the wax)
Process whose purpose is to optically differentiate the cells, cellular constituents and tissue constituents by variation in color
STAINING
Routine staining method used for tiasues
HEMATOXYLIN AND EOSIN METHOD
Process of putting coverslip on the stained tissue using mounting medium to stick the coverslip on the slide
Mounting
It is done to facilitate the handling of the slide to prevent damage to the section
Mounting
It is a means of identification of the specimen; the year, S or A, and number are indicated on one end of the slides
Labeling
Complete removal of calcium salts from the tissue following fixation
Decalcification
4 types of decalcification
- Acids
- Chelating agents
- Ion exchange resin
- Electrolytic method
In acid method, the common slides are:
Nitric acid(5-10%)
Formic acid(5%)
Formic acid-sodium citrate soln
Hydrochloric acid (1%)
Trichloroacetic acid(5%)
Chromic acid (Flemmings fluid)
Perenyi’s Fluid
This acid frequently develop a yellow color due to the formation of nitrous acid and the addition of .1% urea to the concentrated soln temp arrests discoloration
5-10%Nitric Acid
Decal time of nitric acid
1-3 days
Formula of nitric acid
5-10mL Conc HNO3
100mL D. H20
Recommended for post-mortem and research tissue
Formic acid
Decal time of Formic acid
2-7 days
Recommended for research purpose, bone marrow and autopsy
Formic acid-Sodium citrate soln
decal time of Formic acid-Na citrate soln
2-7 days
Recommended for urgent biopsies
1% HCl
Decal time of 1% HCl
1-2 days
Recommended for small spicule of delicate tissues
5% TCA(trichloroacetic acid)
Decal time of TCA
4-6 days
It is a very weak decal agent and not used for DENSE tissue
5% TCA
For routine purpose, for minute biopsies
Chromic Acid (Flemming’s Fluid)
It may be used as a decal agent and a fixing agent
Chromic acid or Flemming’s fluid
Recommended for routine work
Perenyo’s fluid
Decal time of Chromic acid
2-6 days
Decal time of perenyi’s fluid
2-8 days
Decalcifies and softens bones at the same time
Perenyi’s fluid
These are substances that combine with calcium ions, other salts like iron and magnesium deposits to form weakly dissociated complexes and facilitate removal of calcium salt
Chelating agents
These are recommended for detailed microscopic studies
Chelating agents
This is a rapid commercial decalcifying agent consisting of a solution of a chelating agent in dilute hydrochloric acid
Cal -Ex
This solution combines with calcium and forms soluble non-ionized complexes
Versene (EDTA)
Decalcification time of Cal-Ex
2-24 hrs
Decalcification time of Versene (EDTA)
2-4 days
An ammonium form of polysterene resin which is addedto the decalcifying solution to speed up the process of decalcification
Ion exchange resin
Common choice of decalcifying agent when adding ion exchange resin
It consists of a nonmineral acid
Formic acid
A process whereby insoluble calcium salts in the bone are changed to an ionizable salt and acid by the electrical fields between the electrodes causing calcium ion to migrate to the cathode
Electrolytic method
This method is recommended for small fragments of bones, processing tissue paper on a limited number of time
Electrolytic method
Decalcification time of electrolytic method
1-4 hrs
This is apt to produce needle tract artifact and destroys cellular details and also small calcified foci may not be detected
Physical/mechanical test by needling
It is very expensive although the most ideal and most reliable method of determining extent of the calcification due to its ability to detect even the smallest focus of calcium which remains opaque in any xray plate
Xray or Radiological test
In chemical testing, if result: fluid is clear
Complete Decalcification
In chemical testing, if result: fluid is cloudy
Incomplete Decalcification
3 staining methods of decalcified Bones
1) by using modified Harris (or Ehrlich’s )hematoxylin-eosin staining method
2) by using harris hematoxylin and van Gieson’s stain
3) by using Schmorl’s picrothionine stain
Stain which is excellent for demonstrating the canalicular structure of the bone because it forms a thionine-picrate ppt in the canaliculi
Schmorl’s picrothionine stain
Color of bone canaliculi, cells and nuclei in Schmorl’s picrothionine stain
Blue to blue-black
Color of bone matrix in Schmorl’s picrothionine stain
Yellowish
Color of cartilage ground substance in Schmorl’s picrothionine stain
Purple
