Melanin
Validation Stain: Fontana Masson
Other Applicable Stains: Schmorl Melanin
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PRODUCT SPECIFICATIONS:
Tissue: Positive staining skin.
Fixation: Formalin 10%, Phosphate Buffered (Part 1090).
Section/Glass: Paraffin sections cut at 4 microns on Superfrost™ Plus slides.
Quality Control Stain: Fontana Masson quality control stained slide(s) included.
Reactivity: Guaranteed product specific reactivity for one year from date of receipt. Revalidate after one year to verify continued reactivity.
Storage: 15-30°C in a light deprived and humidity controlled environment.
Intended Use: To verify histological techniques and reagent reactivity.
Before using unstained control slides, review the enclosed stained slide(s) to ensure that this tissue source is acceptable for testing needs.
CONTROL SLIDE VALIDATION:
With Fontana Masson Stain Kit: | Part 9105A | Individual Stain Solution | |
Solution A: | Silver Nitrate 10%, Aqueous | 250 ml | Part 13806 |
Solution B: | Ammonium Hydroxide 28-30%, ACS | 250 ml | Part 1006 |
Solution C: | Gold Chloride 0.2%, Aqueous | 250 ml | Part 11286 |
Solution D: | Sodium Thiosulfate 5%, Aqueous | 250 ml | Part 1389 |
Solution E: | Nuclear Fast Red Stain, Kernechtrot | 250 ml | Part 1255 |
APPLICATION:
Newcomer Supply Melanin Control Slides are for the positive histochemical staining of melanin in tissue sections.
PRESTAINING PREPARATION:
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- Heat dry sections in oven according to your laboratory protocol.
- All glassware/plasticware must be acid cleaned prior to use.
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- See Procedure Notes #1 and #2.
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- Prepare Fontana Silver Working Solution (diamine silver) in an acid cleaned Erlenmeyer flask:
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- Solution A: Silver Nitrate 10%, Aqueous; 25 ml
- Add Solution B: Ammonium Hydroxide 28-30%, ACS drop by drop, mix with swirling motion until solution clouds, then clears. Use caution to not add excess Ammonium Hydroxide.
- Add more Solution A: Silver Nitrate 10%, Aqueous drop by drop until clear solution becomes slightly cloudy.
- Let solution stand for 2-4 hours before use.
- For use; after standing, filter the solution. Combine 20 ml of this filtered diamine silver solution with 40 ml of distilled water; 60 ml total.
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NEWCOMER SUPPLY VALIDATION PROCEDURE:
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- Deparaffinize sections thoroughly in three changes of xylene, 3 minutes each. Hydrate through two changes each of 100% and 95% ethyl alcohols, 10 dips each. Wash well with distilled water.
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- See Procedure Notes #3 and #4.
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- Immerse slides in the Fontana Silver Working Solution (Step #3) in a 45°-60°C water bath for 1 hour.
- Check slides microscopically; remove control, rinse in warm distilled water. Confirm that reaction is complete when granules are dark brown and background is colorless.
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- Return to heated Fontana Silver Working Solution for longer incubation if indicated.
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- Rinse well in three changes of distilled water.
- Immerse in Solution C: Gold Chloride 0.2%, Aqueous; 10 minutes.
- Rinse well in distilled water.
- Place in Solution D: Sodium Thiosulfate 5%, Aqueous; 5 minutes.
- Rinse well in distilled water.
- Counterstain in Solution E: Nuclear Fast Red Stain, Kernechtrot for 5 minutes.
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- Shake solution well before use; do not filter.
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- Rinse well in distilled water.
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- See Procedure Note #5.
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- Dehydrate quickly in two changes each of 95% and 100% ethyl alcohol. Clear in three changes of xylene, 10 dips each; coverslip with compatible mounting medium.
- Deparaffinize sections thoroughly in three changes of xylene, 3 minutes each. Hydrate through two changes each of 100% and 95% ethyl alcohols, 10 dips each. Wash well with distilled water.
RESULTS:
Melanin | Black |
Nuclei | Pink-red |
PROCEDURE NOTES:
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- Acid clean all glassware/plasticware (Part 12086) and rinse thoroughly in several changes of distilled water.
- No metals of any kind should come in contact with silver solutions to prevent precipitation of silver salts. Use plastic forceps (Part 5500) or paraffin coated metal forceps.
- Drain slides after each step to prevent solution carry over.
- Do not allow sections to dry out at any point during procedure.
- Wash well after Nuclear Fast Red Stain, Kernechtrot to avoid cloudiness in dehydration steps.
- If using a xylene substitute, follow manufacturer’s recommendation for deparaffinization and clearing steps.
REFERENCES:
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- Luna, Lee G. Histopathologic Methods and Color Atlas of Special Stains and Tissue Artifacts. Gaitheresburg, MD: American Histolabs, 1992. 286-287.
- Sheehan, Dezna C. and Barbara B. Hrapchak. Theory and Practice of Histotechnology. 2nd ed. St. Louis: Mosby, 1980. 276-277.
- Modifications developed by Newcomer Supply Laboratory.