fixation Flashcards

1
Q

used as a simple fixative

A

ethyl alcohol

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2
Q

fixative for routine post mortem

A

formol HgCl soln

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3
Q

mechanism in fixation which is not incorporated but alters the conposition of tissues by removing the bound water

A

non additive fixation

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4
Q

pH in fixation

A

pH 6-8

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5
Q

temperature in fixation?
for electron microscopy/histochem?
for rapid fixation?
for tissues w/ TB?

A

πŸ’Ž room temp
πŸ’Ž 0-40 C
πŸ’Ž 60 C
πŸ’Ž 100 C

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6
Q

fixative that preserve chemical constituents of tissue

A

histochemical

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7
Q

thickness of section:
for electron microscope?
for light microscope?

A

πŸ’Ž 1-2 sqmm

πŸ’Ž 2 sqcm

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8
Q

iso/hypotonic soln causes

A

cell swelling

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9
Q

type of fixatives accdg to composition (2)

A

simple and compound

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10
Q

osmolality in fixation?

range?

A

πŸ’Ž slightly hypertonic

πŸ’Ž 400-450 mOsm

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11
Q

fixative that permits the general microscopic study of tissue structures

A

microanatomical

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12
Q

gas produced by oxidation of methyl alc?
buffered to? with?
fixation time?

A

πŸ’Ž formalin
πŸ’Ž pH 7 with phosphate buffer
πŸ’Ž 24 hrs

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13
Q

duration of primary fixation in buffered formalin

A

2-6 hrs

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14
Q

duratin of fixation for electrom microscopy? then?

A

3 hrs; then placed in holding buffer

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15
Q

recommended for nuclear prep

A

flemming’s soln

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16
Q

saturated formaldehyde

A

10% formol saline

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17
Q

for central nevous tissues and general post mortem tissues for histochem staining

A

10% formol saline

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18
Q

prevents precipitation of acid formalin pigments

A

10% neutral buffered formalin

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19
Q

concn of formaldehyde?
glutaraldehyde?
glutaraldehyde (for immune-electron microscope)?

A

πŸ’Ž 10%
πŸ’Ž 3%
πŸ’Ž 0.25%

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20
Q

process of removing excess fixative

A

washing out

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21
Q

recommended for preservation and storage of surgical, post mortem and research specimens

A

10% neutral buffered formalin

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22
Q

alcohol recommended for routine dehydration of tissues

A

ethyl alc

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23
Q

% of glutaraldehyde for small tissue? how long?

for large tissue? how long?

A

πŸ’Ž 2-5% for 2-4 hrs

πŸ’Ž 4% for 6-8 hrs to 24 hrs

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24
Q

made up of two or more fixatives

A

compound fixatives

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25
Q

alcohol that is toxic, primarily employed for blood and tissue films and for smear prep

A

methyl alc

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26
Q

alcoholic formalin

A

gendre’s fixative

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27
Q

most and critical in histotechnology

A

fixation

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28
Q

fixation aims to? (2)

A

πŸ’Ž preserve the morphological and chemical integrity

πŸ’Ž hardenand protect the tissue

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29
Q

fixative for amino acid histochem?
for glycogen fixation?
for human skin?

A

NBFormol saline/ formalddehyde vapor
alcoholic fixatives
alcoholic formaldehyde

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30
Q

fixative that preserve specific parts

A

cytological

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31
Q

fixative which rapidly denatures and precipitates protein by destroying H & other bonds?
concn ranging?(%)
less concentrated soln will produce ____ of cells
% to preserve the color?

A

alcohol
70-100%
lysis
80%

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32
Q

recommended for cytoplasmic structures particularly the mitochondria

A

flemming’s soln without acetic acid

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33
Q

recommended for fixing chromosomes, lymph glands and urgent biopsies

A

carnoy’s fluid

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34
Q

formalin diffuses into the tissues at the rate of?

A

1 mm/hr

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35
Q

how to remove Hg deposits (4 steps)

what process?

A

0.5% lugol’s iodine in 70% ethanol (5-10 mins)
rinsed w/ water
decolorize in 5% Na thiosulfate (5 mins)
washed w/ running water

πŸ’Ž de-zenkerization

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36
Q

recommended for fixing mucopolysaccharide and nuclear proteins

A

newcomer’s fluid

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37
Q

form of secondary fixation whereby a primarily fixed tissue is placed in 2.5-3% K dichromate for 24 hrs

A

post-chromatization

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38
Q

preparation/formula for 10% NBF (4) with wt or volume

A

πŸ’Ž sodium dihydrogen phosphate 3.5 gm
πŸ’Ž disodium hydrogenphosphate 6.5 gm
πŸ’Ž 40% formaldehyde 100 mL
πŸ’Ž distilled h20 900 mL

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39
Q

artifact found in surgical specimens due to intense eosinophilic staining

A

crush artifact

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40
Q

excelent fixative for glycogen

A

brasil’s alcoholic picroformol fixative

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41
Q

for demonstration of chromatin, mitochondria, golgi bodies, etc

A

regard’s (muller) fluid

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42
Q

commonly used fixatives for nucleic acids (3)

A

ethanol
methanol
carnoy’s soln

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43
Q

fixatives contain ___ & ____ to preserve lipids in cryostat

A

hgcl

K dichromate

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44
Q

aldehyde mixtures used for electron cytochem (2)

A

karnovsky’s paraformaldehyde-gluta

acrolein

45
Q

fixation prevents (4)

A

πŸ’Ž degeneration
πŸ’Ž decomposition
πŸ’Ž putrefaction
πŸ’Ž distortion of tissues

46
Q

widely used as secondary fixative

A

hgcl

47
Q

fixative which preserves phospholipids?

cholesterol?

A

baker’s formol-Ca

digitonin

48
Q

for tumor biopsies especially of the skin?

after using this fixative, transfer to?

A

heidenhain’s susa soln

high-grade alcohol

49
Q

% of formaldehyde for working soln?

for stock soln?

A

10%

37-40%

50
Q

for tissue photography

A

metallic fixatives

51
Q

commonly used in pathology for demonstration of various antibodies

A

immunofluorescence techniques

52
Q

to prevent from drying, put the small tissue biopsies into ____

A

peti dish with moistened filter paper

53
Q

fixative used in strong saturated aqueos soln (1%)?
1-2%?
3%?
4%?

A

picric acid
chromic acid
K dichromate
lead fixative

54
Q

commonly used in pathology for demonstration of various antibodies

A

immunofluorescence techniques

55
Q

excess mucus maybe washed by?

A

NSS

56
Q

fiaxtive used for fixing touch prep

A

95% isopropyl alc

57
Q

strong oxidizing agent

A

chromic acid

58
Q

dyes the tissue but the yellow color may be removed by ___

A

picric acid fixative

lithium carbonate/acid dye

59
Q

recommended for acid mucopolysaccharide

A

lead fixative

60
Q

preserves cytoplasmic structures?
contains glacial acetic acid, T/F?
pH?

A

cytoplasmic fixatives
F
> 4.6

61
Q

precipitates all proteins and preserves carbohydrates

A

chromic acid

62
Q

temperature which inactivates enzymes

A

cold temperature

63
Q

fixative which preserves the nuclear structure (chromosomes) ?
primary component?
ph?

A

nuclear fixative

glacial acetic acid

64
Q

fixative for embryos and pituitary biopsies

A

bouin’s soln

65
Q

acts both nuclear and histochemical fixative

A

newcomer’s fluid

66
Q

temperature which inactivates enzymes

A

cold temperature

67
Q

excellent for blood smeArs

A

100% methyl alc

68
Q

fixative useful in the study of nuclear components of cell?

solidifies at what tempearture?

A

glacial acetic acid

17 C

69
Q
used to remove excess:
chromates?
formalin?
picric acid?
osmic acid?
mercuric fixatives?
A
tap water
tap water
50-70% alc
tap water
alcoholic iodine
70
Q

mechanism in fixation in which chemical constituent of fixative becomes part of tissue by forming crosslinks

A

additive fixation

71
Q

type of fixative accdg to action (3)

A

πŸ’Ž microanatomical fixatives
πŸ’Ž cytological fixatives
πŸ’Ž histochemical fixatives

72
Q

human brains:
to prevent from flatenning?
washing out blood by?

A

cord tied under the circle of willis

intravascular perfusion with ringer’s lactate

73
Q

this is done before dehydration and after deparaffinization before staining procedure

A

secondary fixation

74
Q

added to hgcl stock soln forming zenker’s fluid to prevent turbidity and formation of black precipitate

A

glacial Acetic acid

75
Q

recommended for study of early degeneartive processes and tissue necrosis and it demonstrates ricketssiae

A

orth’s fluid

76
Q

method to soften hardened tissue

A

lendrum’s method (running water overnight and immersed in 4% aqueous phenol soln for 1-3 days)

77
Q

hypertonic soln causes

A

cell shrinkage

78
Q

most common metallic fixative

A

HgCl

79
Q

fixative recommended for small pieces of liver, spleen, CT fibers and nuclei?
tissue should be cut in? (mm)

A

zenker’s fluid

2-3 mm

79
Q

excellent microanatomical fixative for pituitary gland, BM, spleen and liver?
added to hgcl stock soln?
to remove brown pigments?

A

zenker-formol/helly’s soln
strong formaldehyde
immerse in NaOH

79
Q

most common chrome-osmium acetic acid fixative

A

flemming’s soln

79
Q

softening effect on dense fibrous tissue

A

trichloroacetic acid

79
Q

artifact found in surgical specimens due to intense eosinophilic staining

A

crush artifact

80
Q

fixative which preserves mitochondria?
pH?
preserves ___ when acidified? (3)

A

K dichromate
4.5-5.2
cytoplasm, chromatin bodies & chromosomes

81
Q

fixative used at ice cold tempearture?

range?

A

acetone

-5 to 4 C

82
Q

procedure which involves thermal coagulation of tissue proteins for rapid diagnosis

A

heat fixation

83
Q

commonlu used fixative for bone marrow biopsies

A

b-5 fixative

84
Q

pale yellow powder which dissolves in water, forming a strong oxdizing soln?
what % and temp?

A

osmium tetroxide

6% at 20 C

85
Q

impotance of secondary fixation (3)

A

facilitate and improve teh demonstration of substance
act as a mordant
for complete preservation

86
Q

method to soften hardened tissue

A

lendrum’s method (running water overnight and immersed in 4% aqueous phenol soln for 1-3 days)

87
Q

large amt of blood should be flushed out by?

A

saline BEFORE fixing

88
Q

fixes conjugated-fats and lipids permanently

A

osmium tetroxide

89
Q

thickness of tissue with lung edema

A

1-2 cm thick

90
Q

to avoid air-filled lungs to floate, it should be covered with?

A

several layers of gauze

91
Q

human brains:
to prevent from flatenning?
washing out blood by?

A

cord tied under the circle of willis

intravascular perfusion with ringer’s lactate

92
Q

well known artifact that may be produced under acid conditions

A

formalin pigment

93
Q

amt of fixative (osmium tetroxide) should be __x the tissue vol

A

5-10x

94
Q

large amt of blood should be flushed out by?

A

saline BEFORE fixing

95
Q

fixation time can be cut down by using? (4)

A

πŸ’Ž heat
πŸ’Ž agitation
πŸ’Ž microwave
πŸ’Ž vacuum

96
Q

used to fix brain tissue for diagnosis of rabies

A

carnoy’s fluid

97
Q

factors t hat affect fixation (retarded by) 5

A

size & thickness (larger, longer)
presence of mucus, fat, blood
cold temperature

98
Q

thickness of tissue with lung edema

A

1-2 cm thick

99
Q

temperature for RNA?

DNA?

A

45 C

65 C

100
Q

to avoid air-filled lungs to floate, it should be covered with?

A

several layers of gauze

101
Q

factors t hat affect fixation (retarded by) 5

A

size & thickness (larger, longer)
presence of mucus, fat, blood
cold temperature

102
Q

maybe used as a weak decalcifying agent

A

trichloroacetic acid

103
Q

well known artifact that may be produced under acid conditions

A

formalin pigment

104
Q

amt of fixative (osmium tetroxide) should be __x the tissue vol

A

5-10x