DECALCIFICATION

Question 1

true or false. decalcification is part of routine tissue processing.

Answer 1

false. not all undergo decalcification.

Question 2

tissue spx that undergo decalcification

Answer 2

bones
teeth
tuberculous organs
arteriosclerotic blood bessels

Question 3

ratio of decal agent to tissue

Answer 3

20:1

Question 4

types of decal agents

Answer 4

acids
chelating agents
ion exchange resin
electrical ionization

Question 5

most widely used for routine decal

Answer 5

acid decal agents

Question 6

most common and fastest decal agent

Answer 6

nitric acid

Question 7

recommended conc of nitric acid

Answer 7

5-10%

Question 8

rapid, recommended for urgent biopsies

Answer 8

aqueous nitric acid (10%) (12-24 hrs)

Question 9

rapid, produces less tissue destruction

Answer 9

formol-nitric acid (1-3 days)

Question 10

decal and softens tissue at the same time, slow

Answer 10

perenyi’s fluid (2-7 days)

Question 11

the MOST rapid decal agent of all

Answer 11

phloroglucin nitric acid (12-24 hrs)

Question 12

inferior to nitric acid but produces good nuclear staining at 1% conc

Answer 12

hydrochloric acid

Question 13

decal agent for teeth and small pieces of bones

Answer 13

von ebner’s fluid (derived from HCl)

Question 14

BEST decal agent

recommended for postmortem research and suitable for immunohistochem staining

Answer 14

5% formic acid

Question 15

what is added to hasten decal of formic acid?

Answer 15

citrate

Question 16

both used as a fixative and decal agent.

suitable for small spicules of bone

Answer 16

trichloroacetic acid

Question 17

very weak decal agent.

suitable for minute pieces of bone

Answer 17

sulfurous acid

Question 18

carcinogenic decal agent

Answer 18

chromic acid

Question 19

decal agent that does not produce cell or tissue distortion

Answer 19

citric acid-citrate buffer solution 4.5 pH

Question 20

chelating agent in decal

Answer 20

EDTA

Question 21

combine with calcium ions to form weakly dissociated complexes and facilitate the removal of calcium ions

Answer 21

chelating agents

Question 22

chelating duration

Answer 22

small spx: 1-3 weeks

dense bones: 6-8 weeks or longer

Question 23

chelating optimum binding capacity

Answer 23

pH 8

Question 24

true or false. EDTA is not suitable for immunohistochem or enzyme staining and electron microscopy

Answer 24

false. EDTA is excellent to use on these.

Question 25

this method works by removing calcium ions from formic acid-containing decal solutions

Answer 25

ion exchange resin

Question 26

what resin is used on ion-exchange resin?

Answer 26

ammonium form of polystyrene resin

Question 27

ion exchange resin is not recommended on:

Answer 27

nitric acid and hydrochloric acid

Question 28

which decal agent is added in ion exchange resin?

Answer 28

formic acid (20-30x)

Question 29

process where positively charged calcium ions are attracted to a negative electrode and subsequently removed from the solution

Answer 29

electrophoresis

Question 30

time of calcium is shortened due to:

Answer 30

heat and the production of electrolytic reaction

Question 31

which decal agent is added in electrophoresis?

Answer 31

88% formic acid

Question 32

hastens decal (3):

Answer 32

concentration temp agitation

Question 33

retards decal:

Answer 33

increase in size and consistency

Question 34

done by touching or bending the tissue

Answer 34

physical or mechanical test

Question 35

decal measurement that is routinely used

Answer 35

chemical method

Question 36

cloudy soln chemical check:

Answer 36

incomplete decal

Question 37

clear soln chemical check:

Answer 37

complete decal

Question 38

very expensive but the most ideal, sensitive, and reliable method to determine extent of decal

Answer 38

x-ray or radiologic method

Question 39

x-ray method is not recommended to what type of tissues?

Answer 39

mercuric chloride-fixed tissues

Question 40

ways to do post-decal:

Answer 40

1. lithium bicarbonate/sodium bicarbonate 2. rinse in tap water 3. formol-saline w/ sucrose or phosphate-buffered saline w/ sucrose

Question 41

this may be required for unduly hard tissues

Answer 41

tissue softeners

Question 42

acts as both decal agent and tissue softener

Answer 42

perenyl's

Question 43

tissue softener that makes use of 4% phenol

Answer 43

lendrum's

Question 44

tissue softener that leaves a soapy and swollen effect

Answer 44

molliflex

Question 45

optimum temperature for decalcifying

Answer 45

18-30 C (room temp)

Question 46

ideal time required:

Answer 46

24-48 hours