Adhesives and mounting media

• Mounting


  e last step in tissue processing that results in a permanent histological preparation suitable for microscopy, after adhesion of the sections on to the slide and appropriate staining of the tissue
• ADHESIVES


  substance which can be smeared on to the slides so that the sections stick well to the slides
• Albumin


  most commonly use adhesive
• Albumin solution

  prepared by mixing equal parts of glycerin, distilled water and white of eggs, then filtered through coarse filter paper and a crystal of Thymol is added.
• Poly-L-lysine


  a favorite adhesive, can be bought as a 0.1 % solution and further diluted (1 in 10 with distilled water) when ready to use. Sections are coated with this dilute poly-L-lysine and allowed to dry. With time, the adhesive ability of this substance slowly loses its effectiveness. Therefore the coated slides should be used within a few days.
• Aminopropyltriethoxysilane (APES)


  better section adhesive and coated slides can be stored for a long time.
• Mayer's Egg Albumin

  FORMULA:

  Egg White 50 cc.

  Glycerin 50 cc.

  Filter and add about 100 mg. crystals of thymol to prevent the growth of molds
• Mayer's egg albumin


  most commonly used because it is very easy to make, is convenient, and is relatively inexpensive
• Dried Albumin


  dried, and stored in 70% alcohol until it is ready for staining
• Dried Albumin


  FORMULA

  Dried albumin 5 gm

  Sodium chloride 5 gm

  Dissolve in 100 cc. of Distilled Water and add crystals of thymol.
• Gelatin (1%)


  FORMULA:

  Gelatin 1 gm

  Distilled water 100 ml

  Glycerol 15 ml Phenol Crystal 2 gm

  Adding up to 30 ml of 1% aqueous gelatin to the water in a floating out bath and mixing it well is a most convenient alternative to direct coating of slides.
• Gelatin-formaldehyde mixture


  FORMULA:

  1% gelatin 5 ml

  2% formaldehyde 5 ml

  Coat the slides with the above mixture.

  Allow coated slides to dry at 37°C for one hour or overnight before use.
• Poly-L-Lysin e


  This aqueous detergent can be purchased as a 0.1% solution which is further diluted 1:10 with distilled water (final dilution to 0.01%) prior to use
• APES (3-aminopropylthriethoxysilane)


  very useful in cytology, particularly for cytospin preparations of proteinaceous or bloody material. The slides are dipped in 2% APES in acetone, drained, dipped in acetone, drained again, and finally dipped in distilled water
• MOUNTING MEDIUM


  -usually a syrupy fluid applied between the section and the coverslip after staining, setting the section firmly, preventing the movement of the coverslip.

  -It protects the stained section from getting scratched, to facilitate easy handling and storage of the slides, and to prevent bleaching or deterioration due to oxidation, thereby preserving the slides for permanent keeping.
• AQUEOUS MOUNTING MEDIA


  used for mounting sections from distilled water when the stains would be decolorized or removed by alcohol and xylene as would be the case with most of the fat stains (Sudan methods) or for metachromatic staining of amyloid.
• Water


  ow refractive index, is moderately transparent and evaporates easily, hence is good only for temporary mounting.
• Glycerin


  also be used as a preservative. It has a high index of refraction and provides greater visibility if slightly diluted with water (for moist sections).
• Glycerin


  This is a very suitable semi-permanent mounting medium with a refractive index of 1.46,
• GLYCERIN JELLY (KAISER'S 1880


  (Refractive Index 1.47)
• GLYCERIN JELLY


  FORMULA:

  Gelatin 10 gm.

  Glycerol 70 ml.

  Distilled water 60 ml.

  Phenol crystals (preservative) 0.25 gm. Gelatin is added to distilled water and incubated in a water bath at 60°C until dissolved.
• Glycerin jelly


  standard mounting medium used when dehydration and clearing with xylene cannot be made (as in fat stains).
• FARRANT'S MEDIUM

  Refractive Index 1.43
• FARRANT'S MEDIUM


  FORMULA:

  Gum arabic 50 gm.

  Distilled water 50 ml.

  Glycerol 50 ml.

  Sodium merthiolate 0.025 gm.

  Dissolve gum arabic in distilled water with gentle heating and add glycerol and sodium merthiolate. Mix well and label
• Arsenic trioxide may be used as a substitute of sodium merthiolate for preservation of the medium. Addition of 50 gm. potassium acetate will produce a neutral (pH 7.2) instead of an acid (pH 4.4) medium, and therefore, will raise the refractive index to 1.44.
• APATHY'S MEDIUM


  Refractive Index 1.52
• APATHY'S MEDIUM


  FORMULA:

  Pure gum arabic (crystals not powder) 50 gm.

  Pure cane sugar or sucrose 50 gm.

  Distilled water 50 ml.

  Thymol crystals 0.05 gm
• APATHY'S MEDIUM


  medium is used for methylene blue-stained nerve preparations and as a general purpose aqueous mountant. It is one of the most useful aqueous mountants for fluorescent microscopy
• BRUN'S FLUID


  FORMULA:

  Glucose 24 gm.

  Glycerine 6 ml.

  Spirits of camphor 6 ml.

  Distilled water 84 ml.

  Mix, shake well, and filter. Store the solution in a well-stoppered bottle.
• BRUN'S FLUID


  recommended for mounting frozen sections from water.
• RESINOUS MOUNTING MEDIA


  used for preparations that have been dehydrated and cleared in xylene or toluene, and are recommended for majority of staining methods
• Canada Balsam

  Refractive Index 1.524
• Canada Balsam


  natural resin extracted from the Canadian tree, Abus Balsamea, usually dissolved in xylene in an incubator at 37°C or paraffin oven at 58 °C, and filtered, obtaining the desired consistency by controlled evaporation of the solvent.
• Canada balsam


  recommended for whole mounts and for thick sections because it does not shrink much
• DPX - (Dibutyl Phthalate and Xylen)

  Refractive Index 1.532
• DPX


  resinous medium recommended for small tissue sections but not for whole mounts because of shrinkage produced on drying; hence, it should be used in excess amounts.
• XAM


  Refractive Index 1.52
• XAM


  synthetic resin mixture in xylene, available in a pale yellow or colorless solution. It dries quickly without retraction, and preserves stains well. Sections are quickly mounted from xylene.
• CLARITE


  Refractive Index 1.544
• CLARITE


  synthetic resin which is soluble in xylene (it is used as a 60% solution in xylene), and is generally preferred over D.P.X. Other recommended synthetic mounting media include Permount (made by Fisher Scientific), H.S.R. (Harleco Synthetic Resin), and Clearmount (Gurr).