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