Fixation

Question 1

Primary Objective of Fixation

Answer 1

To stabilize proteins which would preserve tissues and cellular components in a life-like state that would present autolysis and putrefication.

Question 2

Classification according to Action

Answer 2

Microanatomical
Cytological
Histochemical

Question 3

Permit the GENERAL microscopic
study of the structures without altering the
structural pattern and normal intercellular
relationship of the tissues in question.

Answer 3

Microanatomical Fixatives

Question 4

Preserves the specific parts and
particular microscopic elements of the cell
itself

Answer 4

Cytological Fixative

Question 5

Characteristics of a “ideal” fixative

Answer 5

1. Cheap
2. Stable
3. Safe to handle
4. Must only produce minimum shrinkage and distortion of cell components
5. Hardens tissue
   .6. Isotonic for minimal physical and chemical
   alteration of the cells.
6. Permit the application of many staining procedures

Question 6

True or False. It should have at least ONE

characteristic to be considered a “good” fixative

Answer 6

False. Fixative should have at least TWO or MORE of the characteristics to be considered a “good” fixative.

Question 7

From oxidation of methyl alcohol

Answer 7

Formalin

Question 8

Pure Stock Solution - Highest concentration of Formalin equal to 100%

Answer 8

37-40% Formalin

Question 9

Usual dilution of Formalin or % solution.

Answer 9

10% Formalin solution

Dilution: 1:10 or 1:20

Question 10

Formalin Pigments are formed from?

Answer 10

Acidic formalin solutions due to formation of formic acid by oxidation of formalin.

Question 11

Removing Formalin Pigment

Answer 11

Kardasewitsch Method
Lillie’s Method
Picric Acid Method

Question 12

Measurements by which Pathologists cuts small portion of the organ.

Answer 12

3-5 mm thickness

3 by 2.5 cm in area

Question 13

A microanatomical fixative recommended for fixation of CNS and GENERAL post mortem
tissues and SILVER IMPREGNATION

Answer 13

10% Formol Saline

Question 14

Considered as BEST GENERAL fixative and for tissues containing IRON GRANULES.

Answer 14

10% NBF

Question 15

10% NBF are most recommended to used for?

Answer 15

preservation and storage of SURGICAL specimens
RESEARCH specimens
Tissues with IRON Granules
Elastic Fiber preservation

Question 16

Advantages of 10% NBF?

Answer 16

1. Doesn’t cause formalin pigment preventing precipitation of acid.
2. Doesn’t require for post-treatment
3. Fixative of choice in tissues containing Iron pigments.

Question 17

Recommended for routine POST-MORTEM tissues

Answer 17

Formol Corrosive/Sublimate

Question 18

Satisfactory for EM

Answer 18

Glutaraldehyde

Question 19

Most common metallic fixative

Answer 19

Mercuric Chloride

Question 20

Advantages of Metallic Fixative

Answer 20

1. Increase staining Brightness
2. Nuclear Detail
3. Applied for Hematopoietic reticuloendothelial tissues.

Question 21

Recommended for TRICHROME staining and GAA is added before use.

Answer 21

Zenker’s Fluid

Question 22

Heidenhain’s Susa

Answer 22

SKIN TISSUE BIOPSIES

Question 23

Chromate Fixatives

Answer 23

ROCK

Regaud’s (Moller’s): Chromatin, Golgi bodies, Colloid containing tissue
Orth’s: Rickettsia & Early Tissue Necrosis
Chromic Acid: Carbohydrates
K2CrO4: MITCHONDRIA

Question 24

Recommended for ACID MUCOPOLYSACCHARIDE & CT Mucin

Answer 24

Lead Fixative

Question 25

Best for GLYCOGEN demonstration & allows brilliant staining with the TRICHROME METHOD

Answer 25

Picric acid

Question 26

Picric acid fixative for EMBRYOS

Answer 26

Bouin's Solution

Question 27

A NUCLEAR fixative used to form COMPOUND soln. that fixes and precipitates NUCLEOPROTEINS (Chromosome & Chromatin)

Answer 27

Glacial Acetic Acid

Question 28

Methanol

Answer 28

BM and Blood Smears

Question 29

Isopropanol

Answer 29

Touch Preparations

Question 30

Gendre's Fixative (Alcoholoc Formalin)

Answer 30

SPUTUM that coagulates mucus

Question 31

Fixes conjugated FATS and LIPIDS permanently

Answer 31

Osmic Acid/Osmium Tetropxide

Question 32

Differentiate Flemming's Solution wit GAA and without GAA

Answer 32

Flemming's with GGA: NUCLEAR preparation and PERMANENTLY fixes fat Flemming's without GAA: CYTOPLASMIC structure (mitochondria)

Question 33

Heat Fixation

Answer 33

Used: Frozen Tissue Sections Bacteriologic Smears

Question 34

Fixing brain tissues for diagnosis of RABIES.

Answer 34

Acetone

Question 35

This process removes excess Fixatives.

Answer 35

Washing Out

Question 36

Enumerate what are removed by the ff. solutions in washing out. 1. Tap Water 2. 50-70% Alcohol 3. Alcoholic Iodine

Answer 36

``` 1. Tap Water - excess chromates, formalin, osmic acid (NOT Bouin’s) 2. 50-70% Alcohol - excess picric acid (Bouin’s) 3. Alcoholic Iodine - excess mercuric fixatives ```

Question 37

True or False. Formalin Penetration is 1mm/minute

Answer 37

False. | Formalin penetration - 1 mm/hr

Question 38

True or False. Specimen should be transferred > 1 hour to fixative quickly.

Answer 38

False. < 1 hour.

Question 39

Volume of Fixing fluid-to-Tissue

Answer 39

15-20: 1

Question 40

A secondary fixation

Answer 40

Post-chromatizarion

Question 41

Fixation time

Answer 41

6-24 hours

Question 42

Histopathologic Techniques

Answer 42

1. Fixation 2. Decalcification 3. Dehydration 4. De-alcoholization or Clearing 5. Infiltration or Impregnation 6. Embedding 7. Trimming 8. Sectioning 9. Staining 10. Mounting 11. Labelling

Question 43

Factors involved in Fixation ``` pH: Thickness: EM - ____; LM - _______ Temperature: Traditionally @ RT - ___________ For tissues w/ TB - ____________ Osmolality: Slightly Hypertonic - __________ Isotonic - ____________ ```

Answer 43

Factors involved in Fixation ``` pH: 6-8 Thickness: EM - 1-2 mm; LM - 2 cm Temperature: Traditionally @ RT - surgical specimens For tissues w/ TB - Formalin @ 100C Osmolality: Slightly Hypertonic - 400-450 mOSm Isotonic - 340 mOsm ```

Question 44

Formula: 10% NBF

Answer 44

Monosodium phosphate Disodium phosphate 40% Formalin

Question 45

Formula: Zenkers Fluid

Answer 45

Mercuric Chloride Potassium Dichromate GAAA

Question 46

Formula: Helly's - Zenker's Formol

Answer 46

Mercuric Chloride Potassium Dichromate Sodium Sulfate 40% Formaldehyde

Question 47

Formula: Heidenhains

Answer 47

``` Mercuric Chloride NaCl Trichloroacetic Acid GAA Formaldehyde - 40% ```

Question 48

Recommended for demonstration of Ricketssia

Answer 48

Orth's fluid

Question 49

GAA solidifies at ____

Answer 49

17C

Question 50

Precipitates proteins

Answer 50

TCA

Question 51

Acetone fixative is used at ice cold temperature ranging from ____ to ____

Answer 51

-5C - 4C

Question 52

Secondary fixative in Post chromatization

Answer 52

2.5-3% Potassium dichromate