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Rapid Automatic Paraffin Wax Processing

Rapid Automatic Paraffin Wax Processing

In the schedule below, it is presumed that the working day is from 8:00 a.m. to 5:00 p.m.. If other than that, appropriate adjustments should be made.

Tissue Preparation

  • Thickness: As thin as practical, usually about 1 mm maximum. Thicker tissues may not be properly processed.
  • Area: 10 mm × 15 mm. Thin slices that have too large an area will tend to curl, making sectioning the full surface difficult. Submit more than one piece if a larger area is needed.
  • Fixed tissue: Breadloaf large organs and store in NBF for 48 hours. Select tissue from fixed areas and trim to size.
  • Unfixed tissue: Trim to size and fix at least 2 hours with preheated NBF at 65°C in a closed container, or fix with a rapid fixative (e.g. Carnoy).
  • Times: This is a rapid and minimalist processing schedule.
  • Clearing agent: Xylene or another clearing agent that will clear tissues in similar times should be used.
  • Processing time: This schedule requires 5 hours after fixation.

Processing Schedule

It has been presumed that the processor has 12 stations. If it has more than 12, increase the number of absolute ethanol stations first, as clearing and wax infiltration proceed faster with complete dehydration. If it is possible to elevate temperatures, do so in all stations.

  1. Trim fixed tissues during the day and keep in NBF until 4.30 p.m.
    Place in an oven at 65°C for 2 hours during this time.
    Place on processor.
  2. 70% ethanol 15 minutes with elevated temperature.
  3. 95% ethanol 15 minutes with elevated temperature.
  4. First absolute ethanol 30 minutes with elevated temperature.
  5. Second absolute ethanol 30 minutes with elevated temperature.
  6. Third absolute ethanol 30 minutes with elevated temperature.
  7. Fourth absolute ethanol 45 minutes with elevated temperature.
  8. First clearing agent 15 minutes with elevated temperature.
  9. Second clearing agent 15 minutes with elevated temperature.
  10. Third clearing agent 30 minutes with elevated temperature.
  11. First wax at 58°C under vacuum 15 minutes.
  12. Second wax at 58°C under vacuum 30 minutes.
  13. Third wax at 58°C under vacuum 30 minutes.
  14. Cast the blocks, allow to skin over, then gently lower into cold tap water until solid.
  15. Trim and face blocks, then store face down on ice until sectioned.

Notes

  • It should be understood that this processing schedules is a guide only, and the times given may need to be altered to take the type of tissues being processed into account, as well as other local conditions.

Safety Note

Prior to handling any chemical, consult the Safety Data Sheet (SDS) for proper handling and safety precautions.