ADHESIVES, MOUNTING MEDIA AND MICROTOMY Flashcards
COMMON TYPES OF ADHESIVES
MAYER’S EGG ALBUMIN
DRIED ALBUMIN
GELATIN
GELATIN-FORMALDEHYDE MIXTURE
STARCH PASTE
PLASMA
POLY-L-LYSINE
APES (3-AMINOPROPYLTHRIETHOXYSILANE)
dried albumin components
5 grams albumin, 5 g NaCl, 100cc distllled water
gelatin (1%) components
1 gm gelatin, 100m water, 15ml glycerol, 2 gm penol crystals
Gelatin-formaldehyde mixture
1% gelatin 5ml, 2% formaldehyde 5ml
starch paste composition
1 g powdered starch, 30ml water, 2 drops HCl and thymol crystals.
plasma adhesive composition
Plasma is readily available from outdated blood stored in blood banks, dispensed into sterile tubes of 0.5ml each.
can be purchased as a 0.1% solution which is further diluted at 1:10 with distilled water (final dilution to 0.01%) prior to use. Sections are coated with this solution and allowed to dry.
Poly-L-Lysine
widely used as a section adhesive in immunohistochemistry.
Poly-L-Lysine
for cytospin preparations of proteinaceous or bloody material.
APES (3-Aminopropylthriethoxysilane)
Is usually syrupy fluid applied between the section and the coverslip after staining, setting the section firmly, preventing the movement of the coverslip.
mounting medium
CHARACTERISTICS OF GOOD MOUNTING MEDIUM
Avoid tissue distortion
Miscible with xylene and toluene
Should not dry quickly
Should not crack or produce artefactual granularity on the slide upon drying
Should not dissolve out or fade tissue sections
Should not cause shrinkage and tissue distortions
Should not leach out any stain or affect staining
Should not change color or pH
Should set hard, producing permanent mounting of sections
mounting medium 2 main groups
- aqueous media
- resinous mounting media
Are designed to mount water-miscible preparations directly from water in cases where the stain is removed or decolorized with alcohol or xylene
aqueous media
example of aqueous media
water, glycerin
Has low refractive index, moderately transparent and evaporates easily
water
Has high refractive index, provides greater visibility if slightly diluted with water.
Glycerin
Glycerin media example
Glycerin Jelly
Farrant’s Medium
Apathy’s Medium
Brun’s Fluid
Are used for preparations that have been dehydrated and cleared in xylene or toluene.
Resinous Mounting Media
Transparent, almost colorless oleoresin that adheres firmly to glass and sets to a hard consistency without granulation
Canada Balsam
canada balsam is dissolved in xylene in an incubator at ____ or paraffin oven at ___
37 deg.c ; 58 deg celsius
Resinous medium, for small tissue sections
DPX - dibutyl phtalate and xylene (Refractive Index 1.532)
refractive index 1.52
Synthetic resin mixture in xylene
XAM
refractive index 1.544
synthetic resin soluble in xylene
preferred than DPX
clarite
Is the process of sealing the margins of the cover slip to prevent the escape of fluid or semi-fluid mounts and evaporation of mountant
immobilized the coverslip
Prevent sticking of the slides upon storage
ringing
For cutting serial sections of large blocks of paraffin embedded tissues
rocking microtome
For cutting sections for electron microscopy
ultrathin microtome
For cutting paraffin embedded sections
rotary microtome
For cutting celloidin embedded sections
sliding microtome
For cutting umembedded frozen sections
freezing microtome
for manual sharpening when cutting edge has been rendered blunt or nicked
belgium yellow
gives more polishing effect than the belgium yellow
arkansas
much coarser than the first two types and is used only for badly nicked knives followed by either one of the first two knife sharpeners
fine carborundum
hone is about ____ long; remove ____
8”x3” long; remove irregularities
Its surface is wiped clean with a soft moistened with xylene in order to remove the scattered small particles of stones and metal.
Then, covered with a thin film of mineral and clove oil, xylene, liquid paraffin or soapy water for lubrication
hone
direction of hone
Heel (handle end) to toe (head portion) direction
hone knife
10-20x minot/plane wedge knife
Used vibrating frosted glass plate or wheel driven by an electrical motor
Approximately 30 double strokes are given each side of the knife to which very gently pressure is applied
Quite expensive
Time saving
Produced well sharpened knives with uniform levels
MECHANICAL MICROTOME KNIFE SHARPENING
precaution for mechanical microtome knife sharpening
lubricated with warm soapy water or fine oil before using, then washed with water
Presure should be gentle
Strokes should be 20-30x in each direction
After honing wipe off the oil or soap from the knife with xylene
Then strop it thoroughly
BURR formed during honing is removed
To polish and sharpen the cutting edge
Toe to heel direction
Paddle strop made up of best quality horse leather
40-120 double strokes
Stropping (polishing)
PRECAUTIONS IN STROPPING
Knife should be wiped clean with cloth
Knife edge is oiled or greased to prevent rusting
Strop should be treated with vegetable oil (castor oil) applied at the back of the strop not the surface; it should not be used for at least 24-48 hrs after treatment
Mineral oil is NOT recommended
2 types of disposable blades
glass knives
diamond knives
used fro trimming and semi-thin sectioning of tissue blocks for EM
glass knives
cut any type of resin block for electron microscopy
diamond knives
a disposable blades that is Brittle and expensive
Very durable
diamond knives
