TISSUE PROCESSING Flashcards
(53 cards)
1
Q
- optional step
- decalcification is needed
- Bones, teeth, calcified specimens
- Process whereby calcium or lime salts are removed from tissues, following fixation
A
DECALCIFICATION
2
Q
Acid decalcifying agents?
A
- nitric acid
- hydrochloric acid
- formic acid
- trichloroacetic acid
- sulfurous acid
- chromic acid
- citric acid
3
Q
Histopathologic techniques
A
- numbering
- fixation
[decalcification] - dehydration
- clearing
- wax impregmentation
- embedding
- blocking
- trimming
- sectioning
- staining
- mounting
- labelling
4
Q
6 main factors involved in fixation?
A
- hydrogen ion concentration
- temperature
- tissue section thickness
- osmolality
- concentration of fixative
- duration of fixation
5
Q
hydrogen ion concentrations should be ph of ____ to be satisfactory…
A
6-8
6
Q
temperature of fixatives in manual methods is?
A
room temperature
7
Q
the ideal size for light microscopy in fixatives of tissue section thickness is
A
2 cm^2
8
Q
osmolality should be ____ so that it cannot alter the morphology of the cell…
A
slightly hypertonic [400-450 mOsm]
9
Q
concentration of fixative is?
A
low
10
Q
duration of fixation is ____ hrs. once specimen is received…
commonly used reagent/chemical in duration of fixation?
A
2-6
Neutral buffered formalin
11
Q
Types of Aldehyde Fixatives:
A
- formaldehyde [formalin]
- 10% formol saline
- 10% neutral buffered formalin
- formol corrosive [formol sublimate]
- glutaraldehyde
12
Q
- commercially available as 40% PURE STOCK SOLUTION
- pure stock solution are not ideal for routine fixation
- commonly used @ 4% solution, making a 10% formalin for fixation
A
Formaldehyde [formalin]
13
Q
advantages of formaldehyde?
A
- cheap
- readily available
- stable [no storage requirement]
- easy to prepare
- compatible w/ many routine stains
14
Q
disadvantages of formaldehyde?
A
- irritating fumes
- produce shrinkage if prolonged fixation occurs
- produce quality of cytologic staining if unbuffered
15
Q
- Saturated Formaldehyde diluted to 10% with sodium chloride
- Common diluent used: distilled water
A
10% formol saline
16
Q
- saturated formaldehyde diluted to 10% & buffered w/ sodium dihydrogen phosphate & disodium hydrogen phosphate
- Common diluent used: distilled water
- Buffering a solution makes sure that it will reduce shrinkage from happening
A
10% neutral buffered formalin
17
Q
- saturated formaldehyde diluted to 10% using saturated aqeous mercuric chloride [makes this fixative acidic]
A
formol corrosive [formol sublimate]
18
Q
- Made up of two formaldehyde residues linked by three carbon chains
1. ____ solution for small tissues & needle biopsies [2-4 hrs]
2. ____ solution for large tissues (less than 4 mm thick) [6-8 hrs]
A
Glutaraldehyde
1. 2.5%
2. 4%
19
Q
advantages of glutaraldehyde:
A
- more stable effect on tissues
- preserves plasma proteins
20
Q
disadvantages of glutaraldehyde:
A
- more expensive
- less stable as a reagent
21
Q
- Most common metallic fixative (Aq. Solution 5-7%)
- Used as a secondary fixative
- Included with many compound fixatives
- Mercury deposits are removed before staining (0.5% iodine solution in 70% ethanol for 5-10 mins)
component of mixture used to reduce detrimental effect of this fixative.
A
Mercuric chloride
Glacial acetic acid
22
Q
Advantages of Mercuric chloride:
A
-
Nuclear components are shown in
fine detail
23
Q
Disadvantages of Mercuric chloride
A
- Causes marked shrinkage of cells
- Cause precipitation of cells; mercury that will cause confusion in microscopy
24
Q
Example of Chromate fixatives?
A
- chromic acid
- potassium dichromate
25
- **1-2% Aqueous Solution**
- Used as a **component in compound fixatives**
Chromic Acid
26
- **3% Aqueous solution**
- **Preserves lipids**
- In formalin or formaldehyde, lipids are not preserved well
Potassium Dichromate
27
Alcohol dehydrating agents?
1. ethanol
2. methyl alcohol
3. butyl alcohol
28
- **Recommended for routine dehydration** of tissues
- **“best dehydrating agent”**
- **works the fastest & the least hazardous**
Ethanol
29
Used for **blood and tissue films for smear preparations**
Methyl Alcohol
30
- For **plant and animal micro-techniques**
- works the **slowest**
Butyl alcohol
31
Starting point ng babaran sa alcohol?
70-75%
32
Common clearing agents?
- Xylene
- Toluene
33
- **Most commonly used as a clearing agent** ***(1/2-1 hr)***
- Ideally **used on tissue blocks with less than 5 mm thickness**
Xylene
34
Advantages of Xylene?
- most rapid clearing agents
- miscible w/ alcohol & paraffin wax
- cheap
35
Disadvantages of xylene?
- Makes tissues excessively **hard and brittle if used for long periods (>3 hrs)**
- **Not suitable for nervous tissues and lymph nodes**
36
clearing agent used for nervous tissues & lymph nodes?
chloroform
37
- **1-2 hours clearing time**
- Suitable **substitute for xylene or benzene**
## Footnote
benzene - clearing agent but more toxic
Toluene
38
Advantages of toluene?
- Tissues do not become excessively hard or brittle
- Not carcinogenic
39
Disadvantages of toluene?
- More expensive
- Reacts relatively slower than xylene or benzene
40
Melts at 54-58 C (Laboratory temperature must be taken in consideration)
Paraffin wax
41
Advantages of Paraffin wax?
- Individual sections of the **tissue block may be cut with ease**
- **Allows for rapid process (24 hrs)**
- **Tissue blocks may be stored immediately**
42
Disdvantages of Paraffin wax?
- *Overheated* paraffin **makes specimen brittle**
- *Prolonged impregnation* **causes shrinkage of cells**
- **Not recommended for fatty tissues**
43
- Utilizes **micro-anatomical studies of tissue**
- It is a **regressive staining method**
HAEMATOXYLIN AND EOSIN STAINING
44
is used to stain nuclear components
Haematoxylin
45
used for cytoplasmic components
Eosin
46
Nuclei?
blue to black
47
Karyosome?
dark blue
48
Karyosome?
dark blue
49
Cytoplasm?
light pink
50
Cartilage?
pale pink
51
Calcified bone?
purplish blue
52
Decalcified bone matrix, collagen, and osteoid?
pink
53
muscle fibers?
deep pink
