[Histonet] sections falling off

[Olek Michalski]

Well, what can I say? It seemed a little silly to me too but I was told  
this step is for removing fat (myelin) which does not allow a good  
contrast in Nissl staining. Nevetheless most of us use chlorofom/ethanol  
mixture instead of xylene as a first step and I have never seen such a  
strange "ruffling" on sections processed this way even if sections fall  
off sometimes.
It is common here to cut strongly fixed tissue. It is collected in PBS  
filled wells or on gelatin covered slides. In the latter case the sections  
are spread using brush and drop of buffer and air-dried (no alcohol stage  
between cutting and drying). Maybe it would be better to keep them in  
higher temperature for some time as suggested Mary? I am afraid that the  
problem is in too strong fixation. Any comments are wellcome.

Olek Michalski

2008-02-05 19:30:54 Rene J Buesa <rjbuesa <@t> yahoo.com> wrote:

> If they were cryosectioned she did not have to go through xylene or  
> graded alcohols to "dewax and hydrate" since there was no dehydration or  
> wax infiltration to begin with.
>  Cryosectioned sections just need to wash away the medium used to  
> cryosection (OCT perhaps?) and just stain with the aqueous solutions.
>  Later they can de dehydrated and cleared if a permanent mount is  
> desired.
>   Try to float the sections in a water bath and pick them up and don't  
> try again to use xylene or alcohols.
>   Probably she was following a procedure for paraffin embedded tissue  
> that should have been adapted to frozen sections and it was not.
>   René J.
>
> Olek Michalski <olek.michalski <@t> nencki.gov.pl> wrote:
> Dear Histonetters,
>
> a friend of mine just faced a massive sections falling off. She is doing
> Nissl staining in mouse brain (brains perfused with formalin, postfixed 3
> days, and cryosectioned) on poly-L-lysined slides. She just managed to
> pass trough xylene and decreasing grades of alcohol to water and the
> sections started to detach. We were trying to reattach them but it went
> out that sections are not flat any more. It seems like the tissue is
> rehydrated unevenly, but keeping it in water for hours didn't work. Is
> there any way to spread these sections not damaging them at the same  
> time?
> She is likely to rescue this sections even if some work is needed.
>
> Best regards
> Olek Michalski