HISTOPATHOLOGY LEC & LAB

Sectioning/Microtomy

Sectioning

• Cutting tissues into thin slices

• Types of Tissue Sections:

  • Paraffin Sections: 4-6 um

  • Celloidin Sections: 10-15 um

  • Frozen Sections (Cryostat): 4um

Types of Microtome

• Rocking Microtome/Cambridge:

  • Thickness of sections: 10-12 u

• Rotary Microtome:

  • Thickness of sections: 4-6 u

• Sliding Microtome:

  • Thickness of sections: 7-9 um

• Freezing Microtome:

  • Thickness of sections: 10-15 um

• Cryostat or Cold Microtome

• Ultrathin Microtome

Microtome Knives

• Types: Plane Concave, Biconcave, Plane wedge

• Honing & Stropping:

  • Purpose and methods

• Disposable Blades, Glass Knives, Diamond Knives

De-paraffinization

• Methods: Flame, Xylene, Oven

Flotation Water Bath

• Used to remove wrinkles and folds

• Temperature: 6-10 degC lower than wax melting point

Drying of Slides

• Methods: Incubator, Oven, Hot plate

Adhesives

• Types and purposes

• Fishing out: removal of ribbons from the float out bath

Frozen Sections

• Rapid diagnosis in OR

• Methods of Freezing: Liquid nitrogen, Isopentane, Aerosol sprays, Carbon dioxide, Freon 2.2

Temperature Control

• Paraffin Oven: 55-60 degC

• Float out Bath: 45-50 degC

Specialized Stains

• Immunofluorescent & immunohistochemical staining

• Enzyme histochemistry

Conclusion

• Microtomy techniques are crucial in preparing tissue sections for hist