Fixatives

Question 1

When is glutaraldehyde used?

Answer 1

for Electron Microscopy

Question 2

True or False. Glutaraldehyde needs to be diluted also since we cannot use it concentrated.

Answer 2

True

Question 3

Percentage of glutaraldehyde used for small tissue fragments or needle biopsies.

Answer 3

2.5% solution

Question 4

Percentage of glutaraldehyde used for large tissues less than 4mm thick.

Answer 4

4% solution

Question 5

Type of formaldehyde fixative that preserve CNS tissue and post mortem specimens.

Answer 5

10% formol saline

Question 6

This is a diluted form of formalin which uses NSS.

Answer 6

10% formol saline

Question 7

Type of formaldehyde fixative for tissues with iron pigments.

Answer 7

10%NeutralBufferedformalin

Question 8

What is the difference between 10%NeutralBufferedformalin and 10% formalin?

Answer 8

Same with 10% formalin EXCEPT that sodium phosphate is added as a buffer

Question 9

Type of formaldehyde fixative that is used for preserving lipids and neutral phospholipids.

Answer 9

Formol corrosive (Formol sublimate)

Question 10

Composition of Formol corrosive (Formol sublimate).

Answer 10

Formalin + Mercuric Chloride

Question 11

Type of formaldehyde fixative, aside from 10% formalin, used for sputum specimen and for microincineration technique.

Answer 11

Alcoholic formalin (Gendres)

Question 12

Composition of Alcoholic formalin (Gendres).

Answer 12

Ethyl alcohol + Glacial acetic acid + formalin

Question 13

Regarded as the smallest aldehyde but rapid/fast acting.

Answer 13

Glyoxal

Question 14

Enumerate the ALCOHOLIC FIXATIVES

Answer 14

Ethanol
Methanol
Isopropyl (IPA)
Carnoy’s
Newcomer’s

Question 15

What are the 2 fixatives that are used to preserve brain tissue for diagnosis of rabies.

Answer 15

Acetone and carnoy`s fluid

Question 16

Fixative and dehydrating agent for phosphatases and lipases.

Answer 16

Acetone

Question 17

True or False. Acetone must be used at ice cold temperature.

Answer 17

True

Question 18

True or False. Acetone is used In routine tissue processing.

Answer 18

False, it is not used routinely because of its disadvantages: Volatile (evaporates easily), Dissolves fat

Question 19

Considered as the most rapid fixative.

Answer 19

Carnoy’s fluid

Question 20

Type of fixative used for fixing chromosomes and lymph glands.

Answer 20

Carnoy’s fluid

Question 21

Fixative that is excellent for glycogen demonstration.

Answer 21

Picric acid fixative

Question 22

Picric acid is considered a versatile reagent because of its three uses. What are those?

Answer 22

Can be used as decalcifying agent (because it is an acid)
Can be used as a stain
Can also be used as a fixative

Question 23

One of the disadvantage of this fixative is it can impart a yellow color.

Answer 23

Picric acid fixative

Question 24

Give 3 examples of picric acid fixative.

Answer 24

Bouins fluid, Brasils, Hollande`s

Question 25

This fixative is under picric acid fixative and is used to preserve embryos, pituitary biopsies & endometrial curettings but contraindicated for kidney structures and not compatible with Feulgen’s stain.

Answer 25

Bouin’s fluid

Question 26

Fixatives for touch preparations

Answer 26

95% isopropyl alcohol

Question 27

This fixative solidifies at 17degC.

Answer 27

Glacial Acetic Acid

Question 28

At what temperature does glacial acetic acid solidify?

Answer 28

17deC

Question 29

It is a Nuclear fixative (contraindicated for cytoplasmic fixation) that is often used in combination with other fixatives to form compound fixatives.

Answer 29

Glacial Acetic Acid

Question 30

This type of fixative is for mucopolysaccharides and nuclear protein.

Answer 30

Newcomer’s Fixative

Question 31

Give the 3 fixatives that can be used for electron microscopy.

Answer 31

Osmium tetroxide, Glutaraldehyde, Paraformaldehyde

Question 32

This type of fixative can be used for myelin and peripheral nerves (neurologic structures) but is slow in action.

Answer 32

Osmium tetroxide