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UND 363 Font masson
UND 363 Fontana Masson
Question | Answer |
---|---|
purpose for Fontana Masson | demo argentaffin substances (melanin, argentaffin granules of carcinoid tumor, and neurosecretory granules |
principle for Fontana Masson | argentaffin tissue can bind ammoniacal silver and reduce to visible with w/o reducer |
fix for Fontana Masson | NBF, avoid alcohol due to argentaffin dissolving properties, also avoid chromatic and mercuric chloride |
tech | 4-5, chem cleaned glassware and non metalic instruments |
Qc | skin section for melanin, small int/appendix for argentaffin granules |
reagents for Fontana Masson | ammoniacal silver nitrate - impregnation, gold chloride to tone, sodium thio' - remove excess gold and unreduced silver, N fast red - counterstain |
results for Fontana Masson | melanin and argentaffin granules black, nuclei - pink |
since this tech is not specific for melanina dn argentaffin granules what will also give positive reaction | formalin pigment |
what should be done with silver solutions after several days | disposal, may form explosive cmpd. |
what will overstaining do | lead to dirty gray background and loss of contrast |
if the tissue is friable what should be done | use celloidin or the sections will lift off slide |
if ammonia evaporates what will occur and what can fix | leads to poor staining, use closed coplin jar |
what can be done for weak stains | increase temp or extend stain times (prolonged heat to 56○C can lead to precipitate on slide) |
if doing melanin demo what should be done | cut duplicate section and bleach (potassium permanganate, wash and then oxalic acid), stain with N fast red |