Re: mouse feet in paraffin

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From:Barry Rittman <brittman@mail.db.uth.tmc.edu> (by way of histonet)
To:histonet@histosearch.com
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I must agree completely with Gayle. There should not be significant
problems in processing and
sectioning this tissue. It is true that removing the skin will help or as
an alternate shaving the
hairs will help also. Hairs tend to trap air and may hinder penetration of
some agents.
The only tissue that have a tendency to lift are the cartilages on the end
of the bones. Have to be
a little more careful in sectioning, mounting and staining.
Barry

Gayle Callis wrote:

> Sorry to disagree, never had problems with decalcified mouse feet in
>paraffin but never had much
> success with GMA (poor infiltration and controlling polymerization, PMMA
>is a better choice
> here).   Adjustments in fixation, dehydration, and infiltration must be
>made to deal with
> 1) dense connective tissue on foot pads 2) bones close to each other 3)
>skin 4) whole foot
>
> A challenge but know of other labs who successfully section these tiny
>feet.  One lab had a
> series of H&E sections, that looked like footprints walking up a wall, on
>a slide hanging like a
> window pane!
>
> Previous discussion of rat elbows is basically the same technic, works fine.
>
> Having seen the pitter patter of little mouse feet paraffin sections,
>
> Gayle Callis
>
>    ****************************************************
>
>         Dear Taffy & Monique,
>
>         When you think about it, sectioning mouse feet from paraffin is never
> going to work.  What you are working with is tiny pieces of bone,
> cartledge, & hardened skin.  They are going to lift out of the paraffin
> every time
>
>         The only way you are going to get results is to go to resin
>embedding,
> even then you can expect some problems.  I would suggest something that is
> low viscosity with relatively long infiltration times, I don't think it
> would really matter what type of resin.  However, if you used a hydrophilic
> resin (JB4, LR Gold) & therefore didn't have to do any dehydration, then
> you might get some really great results.
>
>         Regards
>
>         Rob W.
>
> At 02:27 07/05/2000 -0500, you wrote:
> >THANK YOU!!!
> >I have been beating myself up over the SAME problem..the mice feet will NOT
> >section..I thought they were not completely fixed..I have shortened the
> >processing time, I have extended the processing time, we have used EDTA to
> >decal as well as Decal I..nothing seems to work. I keep getting the same
> >kind of sections that you describe. Let me know if you find the answer and I
> >will do likewise.
> >GOOD LUCK
> >Taffy Hooser
> >
> >At 09:05 AM 6/29/00 -0700, you wrote:
> >>Hello there,
> >>I just joined the histonet so this will be very helpful to me.  I
> >>received two mice feet to embed and cut, they were fixed then I
> >>decalcified them with Cal-ex.  I processed them as usual and blocked
> >>them, but now when I tried to cut them they won't cut, there is just
> >>a hole in the paraffin sections where the sample is.  When I cut it
> >>sounds as if the bone is still a bit hard so I soaked the blocks
> >>again in Cal-ex to see if that would help and I haven't yet tried to
> >>cut them again.  Does anyone esle have any other suggestions that
> >>will help or is there some other trick for cutting bone this is the
> >>first time I have had to do it.  Thanks for any help.
> >>Monique Tourand
> >>University of Alberta




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