Re: about laser microdissection on paraffin-embeded sections

From:Todd Sherman

Hello Yichao,

Ideally, all of your solutions used in the production of your slides 
should be "RNase free".  This means that you would probably want to use 
millipore, DEPC-treated, autoclaved water when making solutions. 
Further, and this is an unusual but desirable condition, you would 
separate your regular specimens from your research (LCM) specimens. 
This would optimally require a second tissue processor that is cleaned 
and "sterilized", ie. RNase-free.  The solutions should be as fresh as 
possible and only your work load can determine how often to rotate them.

Next, all glassware and containers during the production of your of your 
slides must be RNase free.  Glassware, including slides, should be oven 
baked and handled with gloves at all times.  After mounting, always keep 
the slides well protected. RNAZap 
comes in handy when the containers cannot be baked.  Cut and mount your 
sections the day before you are going to use the LCM.  The same day 
would be ideal but that may be asking too much from the techs. 
Typically, we mounted and stained (H&E) in the afternoon and performed 
LCM the next morning.

These are some of the suggestions I can think of off the top of my head 
to help you control the RNases.  Not comprehensive but a beginning 

Good luck,

Yichao WU, Ph.D candidate queried:

 >Another problem I care about mostly is how would the process of making 
 >paraffin-embeded sections destroy RNA? I believe formalin fixation 
 >would protect RNA,but How about other steps? From the incubation at 
60C >after sticking to slides to the deparaffinization.

Todd Sherman
HistoSoft Corporation
"Biology in a new form..."

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