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Histopath must knows > FIXATION > Flashcards

FIXATION Flashcards

1
Q

Primary aim of FIXATION

A

preserve the morphologial and chemical integrity of the cell in as life-like manner as possible

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2
Q

Most important chemical reaction in fixation?

A

STABILIZE THE PROTEIN

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3
Q

Fixation is best carried at what ph?

A

Neutral pH - pH 7
range 6-8)

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4
Q

Give the optimum temperature of fixation of the ff;
1.Electron microscope
2. tissue processor
3. Fast formalin
4. M. tuberculosis
5. Mast cells

A
  1. Electron microscope 0-4 deg. cel.
  2. Tissue processor 40 deg. cel.
  3. Fast formalin 60 deg cel
  4. M. tuberculosis 100 deg cel
  5. Mast cells at RT
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5
Q

Concentration of FORMALIN, GLUTARALDEHYDE and for EM

A

FORMALIN - 10%
GLUTARALDEHYDE - 3%
EM - 0.25%

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6
Q

How do we fix a specimen suspected for CJD?

A

Immerse in formalin (48 hrs) –> Formic acid (1 hr) –> Formalin (48 hrs)

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7
Q

Alcoholic formalin is AKA

A

Gendre’s fixative

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8
Q

Metallic fixatives and their examples
Mercuric Chloride (BHZZ)
Chromate (CROP)

A

Mercuric Chloride
B-5 fixative
Heidenhain’s Susa
Zenker’s fluid
Zenker-formol (Helly’s fluid)

Chromate
Chromic acid
Regaud’s sol’n
Orth’s sol’n
Potassium dichromate

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9
Q

Alcoholic Fixatives (MINCE)

A

Methyl alcohol (100%)
Isopropyl alcohol (95%)
Newcomer’s fluid
Carnoy’s fluid
Ethyl alcohol (70% - 100%)

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10
Q

Give examples of Osmium tetroxide

A

Flemming’s sol’n
Flemming’s sol’n without acetic acid

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11
Q

A microanatomical fixative must never contain ______ because it inhibits hematoxylin

A

Osmium tetroxide

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12
Q

Give examples of Microanatomical fixatives (10,10 HFZZBB)

A

10% Formol saline
10% NBF
Heidenhain’s susa
Formol Sublimate
Zenker’s sol’n
Zenker formil (Helly’s)
Bouin’s solution
Brasil’s solution

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13
Q

A nuclear fixative must contain ______ as their primary component due to its affinity for nuclear chromatin

A

GAA

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14
Q

Nuclear fixative includes? BFNCH

A

Bouin’s
Flemming’s
Newcomer’s
Carnoy’s
Heidenhain’s Susa

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15
Q

pH for nuclear fixatives?

A

pH of less than 4.6

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16
Q

Cytoplasmic must never contain what compound? Give its examples HROFF

A

Must never contain GAA
Helly’s (Zenker formil
Regaud’s
Orth’s
Flemming’s fluid w/o acetic acid
Formalin with post chroming

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17
Q

Give the examples of Histochemical fixative 10% FANA

A

10% Formol saline
Absolute ethyl alcohol
Newcomer’s
Acetone

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18
Q

Both histochemical and nuclear

A

Newcomer’s solution

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19
Q

Both microanatomic and nuclear

A

Heidenhain’s susa

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20
Q

Both a microanatomic and cytoplasmic

A

Zenker formol (Helly’s)

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21
Q

Both microanatomic and histochemical

A

10% Fomol saline

22
Q

Secondary fixation may be done when?

A

Before dehydration and on deparaffinized sections BEFORE staining

23
Q

Process of post-chromatization?

A

primary fixed tissue placed in aquatic. sol’n of 2.5% to 3% potassium dichromate for 24 hrs

24
Q

What is used to remove excess chromate from tissues fixed in Helly’s, Zenker’s and Flemming’s excess formalin and osmic acid

25
Used to wash out excess amount of picric acid
50% - 70% alcohol
26
Used to remove excessive mercuric fixatives
Alcoholic iodate
27
3 F in lipid fixation
FATS are best demonstrated in FROZEN SECTION using FORMALIN as the fixative
28
Phospholipids are fixed by?
aldehydes
29
Cholesterol can be fixed with ______ for ultrastructure
digitonin
30
Carbohydrate fixation (GAP)
GLYCOGEN can be fixed in ALCOHOLS and PICRIC ACID
31
Most commonly used fixative for Amino Acid histochem or protein fixation
Neutral buffered formol saline or formaldehyde vapor
32
Electron Microscope Fixatives 'GOPKZ"
Glutaraldehyde Osmium tetroxide Paraformaldehyde Karnovsky Zamboni fluid
33
Concentration of Formalin available in commcercial sol'n
37% to 40% considered as 100%
34
How do we remove paraformaldehyde deposits
removed via filtration or adding 10% methanol * methanol can be added as a preservative for formaldehyde
35
Methods in removing formalin pigments
1. Picric acid (saturated alcoholic solution of picric acid) 2. Kardasewtsch's method (Ethyl alcohol and ammonia water 3. Lillie's method (ammonia water, hydrogen peroxide, acetone)
36
Recommended fixative for CNS and general post-mortem tissues
10% Formol saline
37
Best fixative for iron pigment, give it's composition
10% NBF Sodium dihydrogen phosphate Disodium hydrogen phosphate 40% Formaldehyde Distilled water
38
It fixes and dehydrates at the same time, a good preservative of glycogen and for micro incineration technique
Alcoholic formalin (Gendre's fluid) - 95% ethanol saturated with picric acid - Formaldehyde - Glacial Acetic Acid
39
Fixative satisfactory for EM
Glutaraldehyde
40
This is the most common metallic fixative and when fixed it it usually contains black precipitates of ____ except?
mercury chloride Except Susa and can be removed by DEZENKERIZATION
41
MERCURIC CHLORIDE STOCK SOLUTION
- mercuric chloride - potassium dichromate - Sodium sulfate - distilled water
42
Routine fixative of choice for preservation of cell detail in TISSUE PHOTOGRAPHY
MERCURY CHLORIDE
43
What does Zenker formol (Helly's) stain? PBB
Pituitary gland Bone marrow Blood-containing organs
44
Excellent cytologic fixative recommended for tumor biopsies especially for the skin
Heidenhain's susa
45
Fixative used for the cytology of bone marrow
B-5 fixatives
46
Regaud's fixative is recommended for? GMRC
Golgi bodies, Mitochondria, RBC, Colloid containing tissue
47
Orth's fluid is for?
Study of early degenerative processes and tissue necrosis, also recommended for the demonstration of Rickettsia
48
This type of fixative is recommended for Acid mucopoysaccharides
Lead fixative
49
Advantages of Picric acid fixatives, GAP
Glycogen demo Suitable for ANILINE stains Prevents small fragments to be overlooked due to its yellow stain
50
Fixes and dehydrates at the same time
Carnoy's fixative
51
Gives the most usable DNA fragments for PRC
70% to 100% ethyl alcohol
52
Fastest fixative (CURL)
Carnoy's fixative for Chromosome Urgent biopsy Rabies Lymph glands/nodes

Histopath must knows (4 decks)

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