Processing

Description:	processing chapter two
Category:	Histology
Created by:	nperez on 2009-07-21

Question	Answer
take out water	dehydrating
replace alcohol w/a reagent miscible w/parafin	clearing
impregnation, permeation	infiltration
infiltration w/a supporting medium	embedding
chem reagent that can be used for dehydrating and clearing steps in tissue processor.	universal solvent
volatile oils have odor of plant from which they are made	essential oil
water soluble (polyethylene glycols)	carbowax
substance that changes one ion for another. used in decalcification and exchange an ammonium ion for the calcium ion removed from tissue	ion exchange
absorbs water from air so use it over a drying chemical like drierite or an anhydrous calcium chloriee	acetone
removing calcium from bone	decalcification
must be mixable with both dehydrating agent and infiltration medium	clearing agents
organic compounds that have property of binding certain metals,	chelating agent
capable of mixing or being mixed	miscible
alcohol, dioxane, acetone, tetrahydrofuran	dehydrating agents
xylene, toluene, benzene, acetone, chloroform, cedarwood oil, tetrhydrofuran, dioxane, limonene derivatives, aliphatic hydrocarbons	clearing agents
infiltration medium	paraffin
dealcoholization agents	clearing agents
inadequate clearing	inadequate infiltration
soft, mushy tissue	inadequate clearing, inadequate infiltration results in
hard, brittle tissue	prolonged period in clearing agent
most widely used clearing agent, used in processing and staining	xylene
prolonged treatment w/xylene during processing	tissue becomes overhardened
rapid in displacing alcohol, mixiable w/paraffin	xylene
turns cloudy in presence of water	xylene
has PEL of 100ppm, use w/adequate ventilation	xylene
doesnt overharden as much as xylene	toluene
best aromatic clearing agent	toluene
fast acting, doesnt overharden like xylene	benzene
hardens muscle,tendon and uterus more than toluene	benzene
evaporates rapidly from paraffin bath	benzene
when using this clearing agent, the paraffin used for infiltration does not require rotaion and changing as frequently as w/o clearing agents	benzene
carcinoge, affects blood and bone marrow	benzene
leaves tissue less brittle than xylene	chloroform
penetrates slowly, makes clearing a longer process	chloroform
use in tightly covered containers	chloroform
desiccates (dries) connective tissue	chloroform
very volatile, makes fluid levels difficult to maintain in open processor	chloroform and benzene
causes formation of phosgene	heating chloroform
a toxic gas	phosgene
PEL 50ppm, it is carcinogenic	chloroform
low boiling point 58C, will boil off and be replaced by paraffin	acetone
can also be used for dehydration	acetone
Universal solvent	acetone
show more shrinkage than those cleared with xylene	tissues cleared w/acetone
are very volatile	essential oils
volality is not sufficient to allow ready replacment during paraffing infiltration	essential oils
if oil remains in tissue, microtomy is difficult	essential oils
remove w/an aromatic hydrocarbon clearing agent	essential oils
best known most widely used of the oils	cedarwood oil
clears alcohol dehydrated tissue quickly and doesnt cause further shrinkage	cedarwood oil
hardens and damages tissue less than and other known clearing agent	cedarwood oil
tissue may remain in this oil indefinitely	cedarwood oil
are expensive reagents and are not used routinely	essential oils
have become popular during last dacade and have a strong citrus odor	limonene reagents
irritant, sensitizer in concetrated from, causes allergic reactions	limonene reagents
causes difficulty breathing, headaches	limonene reagents
PELS are unavailable for inhalation toxicity	limonene reagents
harden tissue less than xyelene but they cause more contamination of the paraffin	limonene reagents
when used in staining, these reagents are greasier	limonene reagents
newest class of clearing agent	aliphatic hydrocarbons (alkanes)
they are low in reactivity and toxicity	aliphatic hydrocarbons (alkanes)
they are nonirritant and nonsensitizing	aliphatic hydrocarbons (alkanes)
they have an 8hour exposure limit of 300ppm	aliphatic hydrocarbons (alkanes)
used in histo, they penetrate tissue faster, remove fat effectively and allow coverslips to dry in usual manner	light weight (short chains)aliphatics
they dont tolerate water and they are incompatible with some mounting media	disadvantage of aliphatics
difficult to use in areas of high humidity	aliphatic hydrocarbons
can be used on all tissue processors and automated stainers	aliphatic hydrocarbons
not recommended for use on automatic coverslippers	aliphatic hydrocarbons
dioxane, tertiary butanol, tetrahydrofuran, acetone	universal solvent (dehydrating and clearing)
adequate reagent volume must be maintained	to ensure high quality tissue sections
have a schedule for the processor. rotate and change the reagents	to ensure consistant section quality
holds cells and intracellular structures, while thin sections are cut	embedding media
most popular embedding media, large amounts of tissue can be processed in a short time	paraffin
is inert mixture of hydrocarbons produced by craking of petroleum	paraffin
contains beeswax, rubber and other waxes or plastics	commercial paraffin
formed when the firs section cut adheres to microtome knife	ribbons
paraffin becomes harder and provides better support for hard tissue	melting point increases
wax becomes soft and provides less suport for hard tissue	melting point decreases
should be matched to the hardness of tissue to be sectioned	paraffin
enhance ability of paraffin compounds to provide support for hard tissues	additives
55C to 58C	melting point of paraffin
tissue should remain in it the shortest time necessary for good infiltration	paraffin
prolonged heat causes shrinkage and hardening	paraffin
keep supply at 2C to 4C above the melting point	paraffin supply
tissues exposed to overheated paraffin will overhaden, and section quality will be changed, tissue will not be effected	paraffin
must be recorded daily	paraffin temp
will become contaminated w/clearing agentm, if it is not changed and monitored frequently	paraffin
three changes of paraffin are recommended	for infiltration
aided by vacumm	paraffin infiltration
staining problems	overprocessing
difficult to process on the same processing cycle should be processed overinght on an open processor w/o heat and vaccum	bx, uterus, breast and large specimens
dehydrates	alcohol
PEL 1,000 ppm	Ethyl alcohol
clear,colorless,flammable	Ethyl alcohol
drinkable, controlled by federal goverment, troublesome record keeping is required, reliable, fast acting, best dehydrant	Ethyl alcohol
is hydrophillic	Ethyl alcohol
mixable with water as well as organic solvents in all proportions	Ethyl alcohol
should be used in sequence of solutions that gradually increase in concentration	Ethyl alcohol
dehydration process is started at 95%, followed by absolute alcohol	Ehtyl alcohol
causes excessive shrinkage and hardening	Ethyl alcohol
poisonous and rarely used	Methyl alcohol
flammable, unpleasant odor, clear, colorless	Methyl alcohol
PEL of 200	Methyl alcohol
overexposure causes blindness and death	Methyl alcohol
substitute for ethanol	isopropanol
no goverment restrictions. doesnt harden or shrink tissue as much as ethanol	isopropanol
mildly irratant to eyes, nose, throat	isopropanol
PEL of 400 ppm	isopropanol
good dehydrant for plant and animal	butanol
pronounced odor and low dehydrating power.requires long period for dehydration	butanol
excellent dehydrant for slow processing	butanol
causes less shrinkage and hardening than ethanol	butanol
rapid reacting, less expensive, causes excessive shrinkage	acetone
PEL 1,000ppm	acetone
flammable, flash point of -17c	acetone
referred to as emebedding medium. holds cells and intracellular structures in proper relationship while thin sections are cut	infiltration media
Where the tissue cassettes are transported from one solution to next	open system processor
no vacuum used	open system processor
the tissue is stationary and fluids are pumped in and out of the closed chamber holding the tissue cassette	closed system processor
uses vacuum	closed system processor
different protocols based on open or closed system	processor solutions and times
shorter processing cycle is used for bx specimens so they wont be overhardened	processing time
casting or blocking	embedding
enclosing the tissue in the infiltration medium used for processing and then allowing the medium to solidify	embedding
is determined by the embedding medium used	method of processing
side down in the cassette is the side down in the mold	embedding reminders
upside can be notched or inked	embedding reminders
tissue should be in center of mold	embedding reminders
light pressure should be applied over the entire tissue during orientation and light chilling	embedding reminders
wipe forceps inbetween samples to prevent forcep metastasis	embedding reminders
place in a line parallel to the longer axis on the mold	multiple pieces
shuld be facing one side of the mold not up or down	the epithelium
embed on diagnol to aid in the ease of sectioning	bone
GI tract, cysts and gall bladder	tissue w/a wall
embed on an edge so all layers are showing	GI tract, cysts and gall bladder (tissue w/a wall)
fallopian tubes, appendix and arteries	Tubular structures
embed in a cross section so that the lume and all mucosa, submucosa and external muscle layers are obvious	fallopian tubes, appendix and arteries (tubular structures)
micible w/ lower alcohols, water, ether, chloroform, acetone, benzene, toluene, xylene and melted paraffing	tetrahydrofuran
same as dioxane in use but less expensive	tetrahydrofuran
acts rapidly w/o causing excessive shrinkage and hardening	tetrahydrofuran
can be used to dehydrate and clear stained slides	tetrahydrofuran
best universal solvent	tetrahydrofuran
very volatile, offensive odor, explosive peroxides may form, can cause conjuntivities, use in well ventilated room	tetrahydrofuran
produces less shrinkage than ethanol	dioxane
faster dehydrant than ethanol but m/b used in larger volumes	dioxane
can be reused by treating anhydrous calcium chloride or calcium oxide	dioxane
it has water in it, so if itis left in the tissue, it may shrink it up to 50% during infiltration	dioxane
cummulatively toxic, pronounced odor, rarely used	dioxane
Osha PEL 100ppm, NIOSH PEL 1ppm, carcinogen, flammable	dioxane
expensive, tends to solidify at room temp	tertieary butanol

micible w/ lower alcohols, water, ether, chloroform, acetone, benzene, toluene, xylene and melted paraffing	tetrahydrofuran
same as dioxane in use but less expensive	tetrahydrofuran
acts rapidly w/o causing excessive shrinkage and hardening	tetrahydrofuran
can be used to dehydrate and clear stained slides	tetrahydrofuran
best universal solvent	tetrahydrofuran
very volatile, offensive odor, explosive peroxides may form, can cause conjuntivities, use in well ventilated room	tetrahydrofuran
produces less shrinkage than ethanol	dioxane
faster dehydrant than ethanol but m/b used in larger volumes	dioxane
can be reused by treating anhydrous calcium chloride or calcium oxide	dioxane
it has water in it, so if itis left in the tissue, it may shrink it up to 50% during infiltration	dioxane
cummulatively toxic, pronounced odor, rarely used	dioxane
Osha PEL 100ppm, NIOSH PEL 1ppm, carcinogen, flammable	dioxane
expensive, tends to solidify at room temp	tertieary butanol
initial paraffin infiltration must be half tertiary butanol and half paraffin	tertiary butanol
can be used as a dehydrant in the staining process	tertiary butanol
odorus, PEL 100ppm	tertiary butanol
Dealcoholization	clearing
the removal of alcohol, to make tissue receptive to the infiltration medium	clearing
used for processing of tissue and staining of microscopic sections	clearing
hard brittle tissue, sectioning difficult	excessive clearing
reduces crystal size and increases stickiness and adhesion	beeswax
reduces brittleness, increases stickiness and maes the formation of ribbons during sectioning	rubber
other waxes produce smooth texture and smaller crystal size	Paraffin composition
beeswax,rubber and other waxes	Paraffin composition
increases the hardness and support	plastics
infiltrate tissue directly from aqueous fixative	water soluble waxes
will not infiltrate tissue containing large amounts of fat	carbowax