Fixation

Question 1

Defined as the killing, penetration and hardening of tissues

Answer 1

fixation

Question 2

Fixation also be defined as the alteration of tissues by stabilizing _ so that tissues become resistant to further changes

Answer 2

protein

Question 3

primary goal of fixation:

secondary goal of fixation:

Answer 3

primary: preserve
secondary: harden & protect

Question 4

fixation methods
— done in microbiology to fix bacterial smears

Answer 4

heat fixation (physical method)

Question 5

fixation methods
— fixing neurochemical substances in brain like acetylcholine

Answer 5

microwave technique (physical method)

Question 6

fixation method
— immerse/subject/place the specimen in chemical fixatives

Answer 6

chemical method

Question 7

use as holding solutions for tissues to be transported to frozen sections or kidney biopsies for special processing

Answer 7

isotonic solution

Question 8

concentration for EM & immunoEM

Answer 8

3% glutaraldehyde for EM
0.25% glutaraldehyde for immunoEM

Question 9

temperature range that will accelerate fixation

Answer 9

37-56 deg C

Question 10

fixative for EM; required volume is _ the volume of the specimen because it’s quite expensive

Answer 10

Osmium tetroxide; 5-10x

Question 11

Autopsy materials should be fixed as soon after death as possible. If not possible, body must be placed in a _

Answer 11

mortuary ref (temp 4degC)

Question 12

Human Brain must undergo _ washing out of blood by using _

Answer 12

INTRAVASCULAR PERFUSION ; Ringer’s lactate

Question 13

_ should not be dissected before they are fixed

Answer 13

Eyes

Question 14

Hard tissues (cervix, uterine, fibroid etc) must undergo _ immersing specimen in _

Answer 14

LENDRUM’S METHOD ; 4% aqueous phenol for 1-3 days

Question 15

preserves glycogen

Answer 15

picric acid (Brasil’s)

Question 16

liver/spleen fixative

Answer 16

formalin but Zenker’s fluid is better

Question 17

“All fixatives that are available are additive fixatives except _”

Answer 17

acetone
alcohol

Question 18

fixative for brain tissue for the diagnosis of rabies

Answer 18

Carnoy’s & Acetone

Question 19

fixative NOT compatible with kidney

Answer 19

bouin’s

Question 20

water-free (anhydrous) acetic acid that freezes and solidifies at about 17°C.

Answer 20

glacial acetic acid

Question 21

acetic acid major effect

Answer 21

precipitate dna, which is split off from nucleoprotein

Question 22

Excellent for trichrome staining & tissue photography

Answer 22

mercuric chloride

Question 23

mercuric chloride for pituitary gland, BM, liver & spleen

contains potassium dichromate & 40% formaldehyde

Answer 23

helly’s fluid (zenker’s formol)

Question 24

mercuric chloride for connective tissue & nuclei, liver & spleen

contains Glac Hac

Answer 24

zenker’s fluid

Question 25

used to wash out excess mercuric fixatives

Answer 25

alcoholic iodine

Question 26

mercuric fixatives leave

Answer 26

black mercury deposits

Question 27

fixative temperature for EM & histochemistry fixation temperature using autotechnicon

Answer 27

0-4 °Celsius - EM & histochem 40°Celsius- autotechnicon

Question 28

fixative & temperature for rapid fixation of urgent biopsies

Answer 28

formalin @60deg C

Question 29

fixative & temperature for fixing tissues w TB

Answer 29

formalin @100 deg C

Question 30

slow down decomposition of tissue needs to be photographed and cannot be fixed immediately

Answer 30

refrigeration

Question 31

types of fixative according to: i. mechanism of action

Answer 31

additive and non-additive

Question 32

types of fixative according to action

Answer 32

i. microanatomical ii. cytological (cytoplasmic & nuclear) iii. histochemical

Question 33

allows the general microscopic study of tissue structures without altering the structural pattern and normal intercellular relationship of tissues

Answer 33

microanatomical

Question 34

added to prevent precipitation of formaldehyde to white paraformaldehyde

Answer 34

10% methanol

Question 35

CNS tissues & post-mortem tissues

Answer 35

10% formol saline (w/ NSS & sodium chloride)

Question 36

Tissues with iron pigments and elastic fibers

Answer 36

10% Neutral Buffered formalin (NSS + sodium phosphate)

Question 37

formaldehyde for lipids, neutral phospholipids

Answer 37

formol corrosive/ formol sublimate

Question 38

used for: fixing / preserving sputum specimen and MICROINCINERATION TECHNIQUE

Answer 38

Alcoholic formalin (Gendres)

Question 39

mercuric chloride for tumor skin biopsies contains TCA, Glac Hac & formalin

Answer 39

Heidenhain’s Susa

Question 40

mercuric chloride for bone marrow contains anhydrous sodium acetate

Answer 40

B5

Question 41

for carbohydrates

Answer 41

1-2% Chromic acid

Question 42

for lipids, mitochondria

Answer 42

Potassium dichromate (3%)

Question 43

mitochondria, RBC containing colloid tissues

Answer 43

Regaud’s (Moller’s)

Question 44

Rickettsiae & other bacteria, tissue necrosis

Answer 44

Orth’s fluid

Question 45

picric acid can act as

Answer 45

- fixative - decal - stain

Question 46

picric acid remedy for yellow color stain (major drawback)

Answer 46

50-70% alcohol in book: saturated soln of lithium carbonate in 70% alcohol, water. —> 70% ethanol, sodium thiosulfate, water

Question 47

for embryos; pituitary biopsies & endometrial curettings - Not for kidney structures - Not compatible with feulgen’s (demonstrates DNA & RNA)

Answer 47

bouin’s (picric)

Question 48

for GIT biopsies & endocrine tissues

Answer 48

Hollande’s soln (picric)

Question 49

use as raw material in making shabu

Answer 49

acetone

Question 50

Causes: glycogen polarization

Answer 50

alcohol

Question 51

for fixing wet and dry smears, blood smears and BM tissues

Answer 51

methyl alcohol (100%)

Question 52

recommended for touch preparations

Answer 52

isopropyl (95%)

Question 53

for fixing chromosomes and lymph glands - contains absolute alcohol, glacial HAC and chloroform

Answer 53

Carnoy’s

Question 54

classified both as nuclear (to preserve nuclear proteins) and histochemical fixative (can preserve musopolysaccharides)

Answer 54

newcomer’s

Question 55

CT mucins & umbilical cord

Answer 55

rossman’s

Question 56

used to fix myelin and peripheral nerves and for processing neurological tissues

Answer 56

osmium tetroxide

Question 57

solidifies @ about 17deg C

Answer 57

glacial acetic acid