fixation Flashcards
1
Q
used as a simple fixative
A
ethyl alcohol
2
Q
fixative for routine post mortem
A
formol HgCl soln
3
Q
mechanism in fixation which is not incorporated but alters the conposition of tissues by removing the bound water
A
non additive fixation
4
Q
pH in fixation
A
pH 6-8
5
Q
temperature in fixation?
for electron microscopy/histochem?
for rapid fixation?
for tissues w/ TB?
A
💎 room temp
💎 0-40 C
💎 60 C
💎 100 C
6
Q
fixative that preserve chemical constituents of tissue
A
histochemical
7
Q
thickness of section:
for electron microscope?
for light microscope?
A
💎 1-2 sqmm
💎 2 sqcm
8
Q
iso/hypotonic soln causes
A
cell swelling
9
Q
type of fixatives accdg to composition (2)
A
simple and compound
10
Q
osmolality in fixation?
range?
A
💎 slightly hypertonic
💎 400-450 mOsm
11
Q
fixative that permits the general microscopic study of tissue structures
A
microanatomical
12
Q
gas produced by oxidation of methyl alc?
buffered to? with?
fixation time?
A
💎 formalin
💎 pH 7 with phosphate buffer
💎 24 hrs
13
Q
duration of primary fixation in buffered formalin
A
2-6 hrs
14
Q
duratin of fixation for electrom microscopy? then?
A
3 hrs; then placed in holding buffer
15
Q
recommended for nuclear prep
A
flemming’s soln
16
Q
saturated formaldehyde
A
10% formol saline
17
Q
for central nevous tissues and general post mortem tissues for histochem staining
A
10% formol saline
18
Q
prevents precipitation of acid formalin pigments
A
10% neutral buffered formalin
19
Q
concn of formaldehyde?
glutaraldehyde?
glutaraldehyde (for immune-electron microscope)?
A
💎 10%
💎 3%
💎 0.25%
20
Q
process of removing excess fixative
A
washing out
21
Q
recommended for preservation and storage of surgical, post mortem and research specimens
A
10% neutral buffered formalin
22
Q
alcohol recommended for routine dehydration of tissues
A
ethyl alc
23
Q
% of glutaraldehyde for small tissue? how long?
for large tissue? how long?
A
💎 2-5% for 2-4 hrs
💎 4% for 6-8 hrs to 24 hrs
24
Q
made up of two or more fixatives
A
compound fixatives
25
alcohol that is toxic, primarily employed for blood and tissue films and for smear prep
methyl alc
26
alcoholic formalin
gendre's fixative
27
most and critical in histotechnology
fixation
28
fixation aims to? (2)
💎 preserve the morphological and chemical integrity
| 💎 hardenand protect the tissue
29
fixative for amino acid histochem?
for glycogen fixation?
for human skin?
NBFormol saline/ formalddehyde vapor
alcoholic fixatives
alcoholic formaldehyde
30
fixative that preserve specific parts
cytological
31
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?
alcohol
70-100%
lysis
80%
32
recommended for cytoplasmic structures particularly the mitochondria
flemming's soln without acetic acid
33
recommended for fixing chromosomes, lymph glands and urgent biopsies
carnoy's fluid
34
formalin diffuses into the tissues at the rate of?
1 mm/hr
35
how to remove Hg deposits (4 steps)
| what process?
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
💎 de-zenkerization
36
recommended for fixing mucopolysaccharide and nuclear proteins
newcomer's fluid
37
form of secondary fixation whereby a primarily fixed tissue is placed in 2.5-3% K dichromate for 24 hrs
post-chromatization
38
preparation/formula for 10% NBF (4) with wt or volume
💎 sodium dihydrogen phosphate 3.5 gm
💎 disodium hydrogenphosphate 6.5 gm
💎 40% formaldehyde 100 mL
💎 distilled h20 900 mL
39
artifact found in surgical specimens due to intense eosinophilic staining
crush artifact
40
excelent fixative for glycogen
brasil's alcoholic picroformol fixative
41
for demonstration of chromatin, mitochondria, golgi bodies, etc
regard's (muller) fluid
42
commonly used fixatives for nucleic acids (3)
ethanol
methanol
carnoy's soln
43
fixatives contain ___ & ____ to preserve lipids in cryostat
hgcl
| K dichromate
44
aldehyde mixtures used for electron cytochem (2)
karnovsky's paraformaldehyde-gluta
| acrolein
45
fixation prevents (4)
💎 degeneration
💎 decomposition
💎 putrefaction
💎 distortion of tissues
46
widely used as secondary fixative
hgcl
47
fixative which preserves phospholipids?
| cholesterol?
baker's formol-Ca
| digitonin
48
for tumor biopsies especially of the skin?
| after using this fixative, transfer to?
heidenhain's susa soln
| high-grade alcohol
49
% of formaldehyde for working soln?
| for stock soln?
10%
| 37-40%
50
for tissue photography
metallic fixatives
51
commonly used in pathology for demonstration of various antibodies
immunofluorescence techniques
52
to prevent from drying, put the small tissue biopsies into ____
peti dish with moistened filter paper
53
fixative used in strong saturated aqueos soln (1%)?
1-2%?
3%?
4%?
picric acid
chromic acid
K dichromate
lead fixative
54
commonly used in pathology for demonstration of various antibodies
immunofluorescence techniques
55
excess mucus maybe washed by?
NSS
56
fiaxtive used for fixing touch prep
95% isopropyl alc
57
strong oxidizing agent
chromic acid
58
dyes the tissue but the yellow color may be removed by ___
picric acid fixative
| lithium carbonate/acid dye
59
recommended for acid mucopolysaccharide
lead fixative
60
preserves cytoplasmic structures?
contains glacial acetic acid, T/F?
pH?
cytoplasmic fixatives
F
> 4.6
61
precipitates all proteins and preserves carbohydrates
chromic acid
62
temperature which inactivates enzymes
cold temperature
63
fixative which preserves the nuclear structure (chromosomes) ?
primary component?
ph?
nuclear fixative
| glacial acetic acid
64
fixative for embryos and pituitary biopsies
bouin's soln
65
acts both nuclear and histochemical fixative
newcomer's fluid
66
temperature which inactivates enzymes
cold temperature
67
excellent for blood smeArs
100% methyl alc
68
fixative useful in the study of nuclear components of cell?
| solidifies at what tempearture?
glacial acetic acid
| 17 C
69
```
used to remove excess:
chromates?
formalin?
picric acid?
osmic acid?
mercuric fixatives?
```
```
tap water
tap water
50-70% alc
tap water
alcoholic iodine
```
70
mechanism in fixation in which chemical constituent of fixative becomes part of tissue by forming crosslinks
additive fixation
71
type of fixative accdg to action (3)
💎 microanatomical fixatives
💎 cytological fixatives
💎 histochemical fixatives
72
human brains:
to prevent from flatenning?
washing out blood by?
cord tied under the circle of willis
| intravascular perfusion with ringer's lactate
73
this is done before dehydration and after deparaffinization before staining procedure
secondary fixation
74
added to hgcl stock soln forming zenker's fluid to prevent turbidity and formation of black precipitate
glacial Acetic acid
75
recommended for study of early degeneartive processes and tissue necrosis and it demonstrates ricketssiae
orth's fluid
76
method to soften hardened tissue
lendrum's method (running water overnight and immersed in 4% aqueous phenol soln for 1-3 days)
77
hypertonic soln causes
cell shrinkage
78
most common metallic fixative
HgCl
79
fixative recommended for small pieces of liver, spleen, CT fibers and nuclei?
tissue should be cut in? (mm)
zenker's fluid
| 2-3 mm
79
excellent microanatomical fixative for pituitary gland, BM, spleen and liver?
added to hgcl stock soln?
to remove brown pigments?
zenker-formol/helly's soln
strong formaldehyde
immerse in NaOH
79
most common chrome-osmium acetic acid fixative
flemming's soln
79
softening effect on dense fibrous tissue
trichloroacetic acid
79
artifact found in surgical specimens due to intense eosinophilic staining
crush artifact
80
fixative which preserves mitochondria?
pH?
preserves ___ when acidified? (3)
K dichromate
4.5-5.2
cytoplasm, chromatin bodies & chromosomes
81
fixative used at ice cold tempearture?
| range?
acetone
| -5 to 4 C
82
procedure which involves thermal coagulation of tissue proteins for rapid diagnosis
heat fixation
83
commonlu used fixative for bone marrow biopsies
b-5 fixative
84
pale yellow powder which dissolves in water, forming a strong oxdizing soln?
what % and temp?
osmium tetroxide
| 6% at 20 C
85
impotance of secondary fixation (3)
facilitate and improve teh demonstration of substance
act as a mordant
for complete preservation
86
method to soften hardened tissue
lendrum's method (running water overnight and immersed in 4% aqueous phenol soln for 1-3 days)
87
large amt of blood should be flushed out by?
saline BEFORE fixing
88
fixes conjugated-fats and lipids permanently
osmium tetroxide
89
thickness of tissue with lung edema
1-2 cm thick
90
to avoid air-filled lungs to floate, it should be covered with?
several layers of gauze
91
human brains:
to prevent from flatenning?
washing out blood by?
cord tied under the circle of willis
| intravascular perfusion with ringer's lactate
92
well known artifact that may be produced under acid conditions
formalin pigment
93
amt of fixative (osmium tetroxide) should be __x the tissue vol
5-10x
94
large amt of blood should be flushed out by?
saline BEFORE fixing
95
fixation time can be cut down by using? (4)
💎 heat
💎 agitation
💎 microwave
💎 vacuum
96
used to fix brain tissue for diagnosis of rabies
carnoy's fluid
97
factors t hat affect fixation (retarded by) 5
size & thickness (larger, longer)
presence of mucus, fat, blood
cold temperature
98
thickness of tissue with lung edema
1-2 cm thick
99
temperature for RNA?
| DNA?
45 C
| 65 C
100
to avoid air-filled lungs to floate, it should be covered with?
several layers of gauze
101
factors t hat affect fixation (retarded by) 5
size & thickness (larger, longer)
presence of mucus, fat, blood
cold temperature
102
maybe used as a weak decalcifying agent
trichloroacetic acid
103
well known artifact that may be produced under acid conditions
formalin pigment
104
amt of fixative (osmium tetroxide) should be __x the tissue vol
5-10x
