Histopath Lec (Dehydration-Decalcification)

Question 1

is the removal of calcium ions (Ca2+)
from a bone or calcified tissue through a histological process in order to make them flexible and easier to cut

Answer 1

Decalcification

Question 2

Principle of Decalcification

Answer 2

Form soluble calcium salts in an ion exchange that moves calcium into the decalcifying solution

Question 3

Higher concentration of decalcifier = _________________

Answer 3

Faster Decalcification

Question 4

Higher temperature during decalcification = _________________

Answer 4

Increased rate of Decalcification

Question 5

Fluid to tissue ratio during Decalcification

Answer 5

20:1

Question 6

Compound found in bones

Answer 6

Ca10(PO4)6(OH)2
Hydroxyapatite

Question 7

Byproduct of decalcification reaction

Answer 7

6 H2PO4

Question 8

3 Main types of Decalcifying agents

Answer 8

Strong Mineral Acids
Weak Organic Acids
Chelating Agents

Question 9

37 deg C during decalcification = ____________

Answer 9

impaired nuclear staining of Von Gieson’s

Question 10

55 deg C during decalcification = ____________

Answer 10

tissue will undergo complete digestion within 24 hours

Question 11

Ideal time of decalcification

Answer 11

24-48 hours

Question 12

Types of Decalcifiers

Answer 12

ACIDS
CHELATING AGENTS
ELECTRIC IONIZATION

Question 13

Most widely used Type of Decalcifiers

Answer 13

ACIDS

Question 14

Type of Decalcifiers that involves the Exchanging particular ions
within the polymer.
Utilizes EDTA.

Answer 14

Chelating agents

Question 15

Ions move across a gel
membrane, leaving the
tissue, as they are repelled by like charges from electrodes.

Answer 15

Electrophoresis

Question 16

● Moderate acting
● Fixate and decalcify
● For post-mortem tissues
● For excellent nuclear cytoplasmic staining
● For small pieces of bones and teeth

Answer 16

FORMIC ACID

Question 17

For autopsy materials, bone marrow, cartilage, and tissues are studied for research purposes.

Answer 17

FORMIC ACID - SODIUM CITRATE

Question 18

● Inferior to Nitric Acid but produces good staining.
● Slower action and greater distortion to tissue.

Answer 18

HYDROCHLORIC ACID

Question 19

● Does not require washing out before dehydration.
● For teeth and small pieces of bone.

Answer 19

VON EBNER’S FLUID

Question 20

Composition of VON EBNER’S FLUID

Answer 20

(HCI + NaCl + H2O)

Question 21

● Good nuclear staining
● Does not require washing out
● Not recommended for urgent examinations (very slow acting)

Answer 21

TRICHLOROACETIC ACID

Question 22

● Fixative and decalcifying agent
● For minute bone spicules

Answer 22

CHROMIC ACID (FLEMMING’S FLUID)

Question 23

● Most common, very rapid.
● Good nuclear stain.
● Easily removed by 70% alcohol (R-OH).

Answer 23

NITRIC ACID

Question 24

NITRIC ACID is easily removed by _______

Answer 24

70% Alcohol

Question 25

Factors that Influence Decalcification (5)

Answer 25

Concentration Fluid Access Size and Consistency Agitation Temperature

Question 26

● Affect the rate at which Calcium is removed. ● Concentrated acid solutions decalcify more rapidly, but are more harmful to the tissue.

Answer 26

CONCENTRATION

Question 27

● Ready access to all surfaces of the specimen. ● Enhance diffusion and penetration into the specimen if suspected.

Answer 27

FLUID ACCESS

Question 28

● Increase in ____________________ of tissues will require longer periods for complete decalcification. ● Require up to 14 days or longer

Answer 28

SIZE AND CONSISTENCY

Question 29

________________ may increase the rate of Decalcification

Answer 29

Gentle agitation

Question 30

● Increased ___________ will hasten decalcification, but it will also increase the damaging effects of acids on tissue

Answer 30

temperature

Question 31

Optimum temperature for Decalcification

Answer 31

18-30 deg C

Question 32

MEANS OF MEASURING THE EXTENT OF DECALCIFICATION (3)

Answer 32

Physical/ Mechanical (Needle Test) Radiologic Chemical

Question 33

MEANS OF MEASURING THE EXTENT OF DECALCIFICATION: ● a. Inaccurate, vague ● Tissue is pierced with a needle to determine consistency (firm/smooth).

Answer 33

Physical/ Mechanical (Needle Test)

Question 34

MEANS OF MEASURING THE EXTENT OF DECALCIFICATION: ● Most accurate/sensitive but expensive

Answer 34

Radiologic

Question 35

In Radiologic: ● X-Ray film is used - ____________________ = Ca deposits

Answer 35

white discoloration

Question 36

MEANS OF MEASURING THE EXTENT OF DECALCIFICATION: ● Highly recommended ○ Use a litmus paper, ammonia water, & ammonium oxalate.

Answer 36

Chemical

Question 37

Expected result of Chemical Test

Answer 37

red/ acidic

Question 38

These substances are not strictly decalcifying agents, but they have mechanisms that contribute to make the tissue softer.

Answer 38

TISSUE SOFTENERS

Question 39

Examples of TISSUE SOFTENERS (5)

Answer 39

4% Aqueous Phenol Molliflex 2% Hydrochloric acid 1% Hydrochloric acid in 70% alcohol Perenyi’s Fluid

Question 40

Tissue softener that takes 1-3 days in action

Answer 40

4% Aqueous Phenol

Question 41

Tissue softener that results to tissues appearing swollen and soapy

Answer 41

Molliflex

Question 42

Tissue softener that is a decalcifying agent at the same time

Answer 42

Perenyi’s Fluid

Question 43

is the process of removing fixative and water from tissue

Answer 43

Dehydration or Desiccation

Question 44

Volume for Dehydration

Answer 44

Not less than 10x the Specimen

Question 45

Most common Dehydrant

Answer 45

Alcohol

Question 46

Tissues are exposed to increasing grades of concentration: _______________________

Answer 46

70% to 95% to 100%.

Question 47

For delicate tissues, particularly embryonic, starting with ________________ is recommended.

Answer 47

30% EtOH

Question 48

_______________________ tend to harden only the surface of the tissue while the deeper parts are not completely penetrated.

Answer 48

Concentrated alcohols 95% or absolute (~100%)

Question 49

Rapid acting dehydrant (0.5-2hrs)

Answer 49

Acetone

Question 50

Dehydrates and clears the specimen (2)

Answer 50

Tetrahydrofuran Triethyl Phosphate

Question 51

Ethylene glycol Monoethyl Ether is also known as _______________

Answer 51

Cellusolve

Question 52

Universal Solvent but toxic

Answer 52

Diethylene Dioxide (DIOXANE)

Question 53

After fixation, the tissue is subjected to dehydration. To avoid contamination of the dehydrant, it may be necessary to change ______________________-

Answer 53

gauze wrapping