Re: Seeking MMA sectioning tips/tricks etc

From:louise renton

Dear Tony,

The first thing to remember when using a motorised microtome is: Mind your 
fingers!! :)

On with my 2 (American) cents worth. Generally we use a cutting speed of 
between 3 and 5mm/sec. The speed that you cut at is governed by the density 
of the block (teeth for instance might be cut slower) and the nimbleness 
with which you can grasp the section with forceps (or flatten with a a 
brush) as it rolls off the block face. We gently flatten the section with a 
brush while simultaneously tensioning it by gripping it with a pair of fine 
pointed forceps.
You might find that wetting with 30% alcohol also eases cutting.

Alignment of the block in relation to the knife edge is also important. We 
like to orient the long axis of cortical bone at right angles to the knife 
to prevent "shattering".

For some reason, we have found that the best sections of our resin (Kplast) 
is with the knife holder set at 0, however, I have  also determined that 
with a new resin I am using, that an adjustment of 2-4 degrees improves 

Hope this helps
Best regards

Louise Renton
Bone Research Unit
South Africa
Tel & fax +27 11 717 2298
"Time flies like an arrow, fruit flies like a banana"

>From: Anthony Norman 
>To: HistoNet Server 
>Subject: Seeking MMA sectioning tips/tricks etc
>Date: Fri, 17 Jan 2003 19:49:22 -0800
>Hello All,
>Well, I ended up going with the Leica 2500E system which arrived today in 
>what I believe is a minor record for getting my university's purchasing 
>dept moving on a product in this price range. Now I have a new toy to play 
>with and my chairman is a tad on the antsy side to get things to look at 
>and publish. So, in the interests of getting up and running quickly, I 
>thought I would ask people's advice on starting points, at least. (they 
>would like to have data for an abstract due in April and the tissues are 
>not going to be here for a couple of weeks still ... plus I am still taking 
>classes and occasionally try to sleep and eat).
>Our blocks consist of rabbit or canine bone/cartilage in a MMA/GMA resin 
>(85/10%) and the block cutting faces are going to be in the range of 3x4 cm 
>(rabbit) and 6x4.5cm (canine) (we don't do anything on a small scale around 
>here). Desired section thickness anywhere from 5-20 um. I'm most interested 
>in learning best cutting speeds (never used a motorized system before) and 
>starting blade angles. I seem to have all sorts of 
>protocols/recommendations for the embedding, laying out of sections and 
>staining, but little to no info on what would seem the slightly more 
>important bit of actually getting the section from the block. Actually, I 
>guess that is my largest anxiety source at present as the engineer side of 
>my brain is warning me about breaking a machine which costs more than 3 
>times my annual salary.
>Anyway, any thoughts, tips etc you might be able to lend as I get this 
>program up to speed would be greatly appreciated!
>Tony Norman
>Graduate Research Assistant
>UW-Bioengineering/Orthopaedics and Sports Medicine
>Seattle, WA

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