[Histonet] Modified GMS Protocols

[Gudrun Lang]

Biological stains were mainly found by trial and error through the century. I think the main goals were to find a good result (for the purpose) within the available resources (cheap / expensive, easy/difficult to get) and with a practical application. 
Later also health-concerns played a role, that eliminated some protocols. I believe, that the "forefathers" had a hard time to find the best-working protocols. And after that, the histological community acts upon the sentence "never change a winning team" and sticks to the protocols. And we have to admit, that the chemical knowledge of the histologists and the histological knowledge of the chemists may be rather decreased than grown bigger. (a lack of universal scientists)

For the diverse oxidants I think (without literature as evidence) it is also a practical matter. The oxidizising result depends on strength of acid and duration of incubation. If you use a very strong oxidant, the time has to be watched very carefully and there is the risk of overoxidation. If you use a weaker oxidant, you have a longer time-space for a sufficient result. (5 min in periodic acid may refer to 20 sek in potassiumpermanganat ?) 

Gudrun



-----Ursprüngliche Nachricht-----
Von: Nipuna Weerasinghe via Histonet [mailto:histonet at lists.utsouthwestern.edu] 
Gesendet: Donnerstag, 28. Dezember 2017 20:30
An: histonet at lists.utsouthwestern.edu
Betreff: [Histonet] Modified GMS Protocols

I would like to know from subject matter expert why KMno4 never used as an alternative oxidant to CrO3 in Modified GMS. Oxidation of 1,2-glycol linkages in carbohydrates to aldehyde groups can be done by KMNO4 and used to do the same in Castella’s potassium permanganate-Schiff reaction, and Gordon and Sweets' reticulum. Moreover, KMNO4 is a strong oxidant that can oxidized aldehyde to carboxylic, so this leads to closer mimicking of function of CrO3.

Also why people only tried periodic and not any other oxidant to replace CrO3. I could not find any primary literates concnering this matter. Only handful of attempts with periodic is there.

Thanks for your answers in advanced

Lip.
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