fixation Flashcards
used as a simple fixative
ethyl alcohol
fixative for routine post mortem
formol HgCl soln
mechanism in fixation which is not incorporated but alters the conposition of tissues by removing the bound water
non additive fixation
pH in fixation
pH 6-8
temperature in fixation?
for electron microscopy/histochem?
for rapid fixation?
for tissues w/ TB?
π room temp
π 0-40 C
π 60 C
π 100 C
fixative that preserve chemical constituents of tissue
histochemical
thickness of section:
for electron microscope?
for light microscope?
π 1-2 sqmm
π 2 sqcm
iso/hypotonic soln causes
cell swelling
type of fixatives accdg to composition (2)
simple and compound
osmolality in fixation?
range?
π slightly hypertonic
π 400-450 mOsm
fixative that permits the general microscopic study of tissue structures
microanatomical
gas produced by oxidation of methyl alc?
buffered to? with?
fixation time?
π formalin
π pH 7 with phosphate buffer
π 24 hrs
duration of primary fixation in buffered formalin
2-6 hrs
duratin of fixation for electrom microscopy? then?
3 hrs; then placed in holding buffer
recommended for nuclear prep
flemmingβs soln
saturated formaldehyde
10% formol saline
for central nevous tissues and general post mortem tissues for histochem staining
10% formol saline
prevents precipitation of acid formalin pigments
10% neutral buffered formalin
concn of formaldehyde?
glutaraldehyde?
glutaraldehyde (for immune-electron microscope)?
π 10%
π 3%
π 0.25%
process of removing excess fixative
washing out
recommended for preservation and storage of surgical, post mortem and research specimens
10% neutral buffered formalin
alcohol recommended for routine dehydration of tissues
ethyl alc
% of glutaraldehyde for small tissue? how long?
for large tissue? how long?
π 2-5% for 2-4 hrs
π 4% for 6-8 hrs to 24 hrs
made up of two or more fixatives
compound fixatives
alcohol that is toxic, primarily employed for blood and tissue films and for smear prep
methyl alc
alcoholic formalin
gendreβs fixative
most and critical in histotechnology
fixation
fixation aims to? (2)
π preserve the morphological and chemical integrity
π hardenand protect the tissue
fixative for amino acid histochem?
for glycogen fixation?
for human skin?
NBFormol saline/ formalddehyde vapor
alcoholic fixatives
alcoholic formaldehyde
fixative that preserve specific parts
cytological
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%
recommended for cytoplasmic structures particularly the mitochondria
flemmingβs soln without acetic acid
recommended for fixing chromosomes, lymph glands and urgent biopsies
carnoyβs fluid
formalin diffuses into the tissues at the rate of?
1 mm/hr
how to remove Hg deposits (4 steps)
what process?
0.5% lugolβs iodine in 70% ethanol (5-10 mins)
rinsed w/ water
decolorize in 5% Na thiosulfate (5 mins)
washed w/ running water
π de-zenkerization
recommended for fixing mucopolysaccharide and nuclear proteins
newcomerβs fluid
form of secondary fixation whereby a primarily fixed tissue is placed in 2.5-3% K dichromate for 24 hrs
post-chromatization
preparation/formula for 10% NBF (4) with wt or volume
π sodium dihydrogen phosphate 3.5 gm
π disodium hydrogenphosphate 6.5 gm
π 40% formaldehyde 100 mL
π distilled h20 900 mL
artifact found in surgical specimens due to intense eosinophilic staining
crush artifact
excelent fixative for glycogen
brasilβs alcoholic picroformol fixative
for demonstration of chromatin, mitochondria, golgi bodies, etc
regardβs (muller) fluid
commonly used fixatives for nucleic acids (3)
ethanol
methanol
carnoyβs soln
fixatives contain ___ & ____ to preserve lipids in cryostat
hgcl
K dichromate
aldehyde mixtures used for electron cytochem (2)
karnovskyβs paraformaldehyde-gluta
acrolein
fixation prevents (4)
π degeneration
π decomposition
π putrefaction
π distortion of tissues
widely used as secondary fixative
hgcl
fixative which preserves phospholipids?
cholesterol?
bakerβs formol-Ca
digitonin
for tumor biopsies especially of the skin?
after using this fixative, transfer to?
heidenhainβs susa soln
high-grade alcohol
% of formaldehyde for working soln?
for stock soln?
10%
37-40%
for tissue photography
metallic fixatives
commonly used in pathology for demonstration of various antibodies
immunofluorescence techniques
to prevent from drying, put the small tissue biopsies into ____
peti dish with moistened filter paper
fixative used in strong saturated aqueos soln (1%)?
1-2%?
3%?
4%?
picric acid
chromic acid
K dichromate
lead fixative
commonly used in pathology for demonstration of various antibodies
immunofluorescence techniques
excess mucus maybe washed by?
NSS
fiaxtive used for fixing touch prep
95% isopropyl alc
strong oxidizing agent
chromic acid
dyes the tissue but the yellow color may be removed by ___
picric acid fixative
lithium carbonate/acid dye
recommended for acid mucopolysaccharide
lead fixative
preserves cytoplasmic structures?
contains glacial acetic acid, T/F?
pH?
cytoplasmic fixatives
F
> 4.6
precipitates all proteins and preserves carbohydrates
chromic acid
temperature which inactivates enzymes
cold temperature
fixative which preserves the nuclear structure (chromosomes) ?
primary component?
ph?
nuclear fixative
glacial acetic acid
fixative for embryos and pituitary biopsies
bouinβs soln
acts both nuclear and histochemical fixative
newcomerβs fluid
temperature which inactivates enzymes
cold temperature
excellent for blood smeArs
100% methyl alc
fixative useful in the study of nuclear components of cell?
solidifies at what tempearture?
glacial acetic acid
17 C
used to remove excess: chromates? formalin? picric acid? osmic acid? mercuric fixatives?
tap water tap water 50-70% alc tap water alcoholic iodine
mechanism in fixation in which chemical constituent of fixative becomes part of tissue by forming crosslinks
additive fixation
type of fixative accdg to action (3)
π microanatomical fixatives
π cytological fixatives
π histochemical fixatives
human brains:
to prevent from flatenning?
washing out blood by?
cord tied under the circle of willis
intravascular perfusion with ringerβs lactate
this is done before dehydration and after deparaffinization before staining procedure
secondary fixation
added to hgcl stock soln forming zenkerβs fluid to prevent turbidity and formation of black precipitate
glacial Acetic acid
recommended for study of early degeneartive processes and tissue necrosis and it demonstrates ricketssiae
orthβs fluid
method to soften hardened tissue
lendrumβs method (running water overnight and immersed in 4% aqueous phenol soln for 1-3 days)
hypertonic soln causes
cell shrinkage
most common metallic fixative
HgCl
fixative recommended for small pieces of liver, spleen, CT fibers and nuclei?
tissue should be cut in? (mm)
zenkerβs fluid
2-3 mm
excellent microanatomical fixative for pituitary gland, BM, spleen and liver?
added to hgcl stock soln?
to remove brown pigments?
zenker-formol/hellyβs soln
strong formaldehyde
immerse in NaOH
most common chrome-osmium acetic acid fixative
flemmingβs soln
softening effect on dense fibrous tissue
trichloroacetic acid
artifact found in surgical specimens due to intense eosinophilic staining
crush artifact
fixative which preserves mitochondria?
pH?
preserves ___ when acidified? (3)
K dichromate
4.5-5.2
cytoplasm, chromatin bodies & chromosomes
fixative used at ice cold tempearture?
range?
acetone
-5 to 4 C
procedure which involves thermal coagulation of tissue proteins for rapid diagnosis
heat fixation
commonlu used fixative for bone marrow biopsies
b-5 fixative
pale yellow powder which dissolves in water, forming a strong oxdizing soln?
what % and temp?
osmium tetroxide
6% at 20 C
impotance of secondary fixation (3)
facilitate and improve teh demonstration of substance
act as a mordant
for complete preservation
method to soften hardened tissue
lendrumβs method (running water overnight and immersed in 4% aqueous phenol soln for 1-3 days)
large amt of blood should be flushed out by?
saline BEFORE fixing
fixes conjugated-fats and lipids permanently
osmium tetroxide
thickness of tissue with lung edema
1-2 cm thick
to avoid air-filled lungs to floate, it should be covered with?
several layers of gauze
human brains:
to prevent from flatenning?
washing out blood by?
cord tied under the circle of willis
intravascular perfusion with ringerβs lactate
well known artifact that may be produced under acid conditions
formalin pigment
amt of fixative (osmium tetroxide) should be __x the tissue vol
5-10x
large amt of blood should be flushed out by?
saline BEFORE fixing
fixation time can be cut down by using? (4)
π heat
π agitation
π microwave
π vacuum
used to fix brain tissue for diagnosis of rabies
carnoyβs fluid
factors t hat affect fixation (retarded by) 5
size & thickness (larger, longer)
presence of mucus, fat, blood
cold temperature
thickness of tissue with lung edema
1-2 cm thick
temperature for RNA?
DNA?
45 C
65 C
to avoid air-filled lungs to floate, it should be covered with?
several layers of gauze
factors t hat affect fixation (retarded by) 5
size & thickness (larger, longer)
presence of mucus, fat, blood
cold temperature
maybe used as a weak decalcifying agent
trichloroacetic acid
well known artifact that may be produced under acid conditions
formalin pigment
amt of fixative (osmium tetroxide) should be __x the tissue vol
5-10x