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UND 363 Aur/Rhodamin
UND 363 Mwave Auramine Rhoadmine Flourescence
Question | Answer |
---|---|
principle for Mwave Auramine Rhoadmine Flourescence | demo myco tuberculosis or other A/F organisms |
Principle | dyes used are basic that floursece at short wavelengths. Using both dyes in combo will yield better results than alone (auramine O & Rhodamine B) |
how do the bacteria gain the flourescence to be seen | mycolic acid in the cell wall stains with the flourochromes in the dyes. |
fix | NBF preferred |
micron | 4-5 (will also need a flourescent microscope) use 40x hi-dry with exciter filter and colorless UV barrier filter |
qc | tissue with A/F organisms, must use Millipore filtered (.45 micron pore size) water, and a negative control from same day workload. |
reagents in order | auramineO-RhodamineB soln', acid alcohol - decolor/diff'r, eriochrome black T - counterstain |
results | A/F bacteria - red (yellow flourescence), background - black |
why is this stain prone to false positives | it is extremely sensitive and highly specific therefore it is difficult for inexperienced microscopists |
if results are questionable with the aur/rho stain what can be used in addition | carbol fuchsin can be used to restain for confirmation of the results (it is NOT possible to then go back to using Aur/rho after carbol fuchsin has been used) |
if there are dead and dying organisms will they still stain | yes, it will still stain dead and dying more so than the carbol-fuchsin method |
why is it important to only use a small amount of rhodamine B? | too large a quantity can quench flourescence (even in low conc.) |
what can occur if rhodamine B concentration is reduced | it will intensify the flourescens of mycobacteria but it will change the flourescence of the auramine o from yellow to orange-yellow and intensifies it. |
what formalin soln's can't be used in this stain and why | zine formalin. it will inhibit flourescence microscopy due to quenching. |