[Histonet] Re: Do I have to destabilize MMA?

[abtdhu <@t> gmail.com]

Thank John very much. I will check out your references. 
Hope we are not only be able to follow the protocol, but fully understand it.

Dorothy

Sent from my iPad

> On Jan 16, 2014, at 1:37 PM, John Kiernan <jkiernan <@t> uwo.ca> wrote:
> 
> Methacrylate monomers are sold with added hydroquinone to inhibit spontaneous polymerization. The NaOH treatment to remove hydroquinone dates from the earliest years of plastic embedding (Newman et al. 1949 Science 110: 66-68).  The NaOH treatment is not necessary, however, because the stabilizing action of hydroquinone can be overcome by simply using a larger amount of the polymerization catalyst. About 2% of either benzoyl peroxide or 1,2-dichlorobenzoyl peroxide will catalyze the polymerization of stabilized methacrylate monomer. See Hayat, MA 1981 Principles and Techniques of Electron Microscopy  Vol 1. Baltimore: University Park Press, pp. 167-168.
>  
> See Baker, JR 1960 Cytological Technique, 4th ed. London: Methuen, pp.77-84 for a thorough but simple explanation of the chemistry of methacrylate embedding. The whole book (which is a classic) is available, free, at http://archive.org.
>  
> John Kiernan
> Anatomy & Cell Biology
> University of Western Ontario
> London, Canada
> = = = 
>> On 16/01/14, Dorothy Hu <abtdhu <@t> gmail.com> wrote:
>> Thanks Jack's answer. I though I shouldn't to destabilization step as well.
>> But my boss wants to do it. Is there a chemical theory behind this? Why
>> previous protocol has this step (it must be reason)? And why the step is
>> skipped now?  I wish I know before approaching my boss.
>> 
>> Additionally, there is a problem always bothering me in plastic sectioning.
>> I often get cortical bone shattering ( crumbly) in the midshaft of long
>> bone. Cortical bone and marrow are operate in the midshaft. I don't know
>> why is that. It's not happen in the two ends of tibia and femur bone. And
>> doesn't happen on ankle bones. Is that because the bone was stored in 70%
>> EtOH too long (~one year)? I think infiltration is good since I did three
>> times, 2 days each infiltration under vacuum condition in 4oC. If I use 40%
>> EtOH to fix and store the bones will help?
>> 
>> One more question. What is advantage if I use perkadox 16 to replace BP as
>> catalyst? Do I have to dry MMA//DBP/perkadox 16 mixture through CaCl2?
>> 
>> Thanks in advance for your help.
>> 
>> Dorothy
>> MGH endocrine histocore
>> 
>> 
>> On Wed, Jan 15, 2014 at 11:02 PM, <abtdhu <@t> gmail.com> wrote:
>> 
>> > I am new to MMA plastic bone technique. Some one gave me his protocol, in
>> > which has NaOH and d-water to wash MMA mixture before drying it in CaCl2.
>> > But others told me I don't need to do the destabilization step. Could any
>> > expert in this area to tell me if this step is necessary? And why have to
>> > do?
>> >
>> > Sent from my iPad
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