Veterinary Clinical Biochemistry and Laboratory Diagnosis-II

SECTION CUTTING AND MOUNTING

Section Cutting 

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• The cutting of excellent quality sections depends upon thorough knowledge of equipment and practical experience.
• Microtomes are mechanical devices used for cutting thin uniform tissue sections.
• The good quality section cutting depends greatly on quality and care of knife.
• The varieties of microtomes are:
  • Rotary microtome
  • Rocking microtome
  • Freezing microtome
  • Sledge microtome
  • Ultramicrotome
• The block is trimmed by removing the excess paraffin all around.
• Attach the block to the holder of microtome.
• Orient the block so that top and bottom of the block is parallel and horizontal to edge of knife .
• Section is cut in a (4-5 µm thickness) microtome.
• Operate the microtome until complete sections are obtained.

Fixing the sections to slides

• Paraffin sections become slightly compressed and creased.
• To remove the creases and flatten the sections, the sections are transferred from the cutting edge of the microtome knife with the help of a spatula to a tissue flotation bath having warm water (40 to 45 ^o C).
• Sections spread out uniformly and are then taken on the clean glass slides coated with Meyer’s albumin – glycerine mixture. Drain off the excess water and lay the slide flat on tray.
• Transfer the section slides to incubator (40-50^◦C) minimum for one hour or overnight at 37^◦ C. This ensures drying of sections. The sections become ready for staining.

Preparations of Albuminized slides

• Mayer’s glycerol –albumnin mixture is prepared by mixing 1 volume of egg white and an equal volume of glycerol.
• Add a small crystal of thymol to prevent growth of bacteria and fungi.
• A small drop of solution is placed on slide and smeared on the surface with finger.