[Histonet] Coverslipping mystery

Adam Boanas a.boanas at epistem.co.uk
Mon Jul 13 02:30:44 CDT 2015

Hello again,

Thought I might offer an update on the coverslipping issue as it might be of use in future.
I ran a test last week of manual coverslipping using blank charged and un-charged slides and using DPX and Pertex as the mountant. I also used 2 methods of application.
1) Mountant applied using plastic Pasteur pipette
2) Mountant applied using aluminium screw cap tube.
Following immersion in xylene for 5 mins the coverslips were applied. From viewing this morning, all slides were clear with the exception of those coverslipped using DPX applied with the Pasteur. In each case, these slides had the 'parched earth' artefact having been left to dry over the weekend.
I suspect that the DPX has had a reaction with the plastic of the pipette during application and the artefact is caused by residual `molten` plastic from the pipette that only reveals itself over time.
Does this sound plausible? No problem with the pertex and pipettes (which is what I've used for years with no issue)

-----Original Message-----
From: Caroline Miller [mailto:mills at 3scan.com] 
Sent: 11 July 2015 15:18
To: John Kiernan
Cc: Adam Boanas; histonet at lists.utsouthwestern.edu
Subject: Re: [Histonet] Coverslipping mystery

I really like DPX, although funnily enough we used cytoseal in my lab in London but always called it the DPX! I think I remember by boss telling me about the bad DPX time.....

When I moved to the USA the lab I started in had a bottle of DPX and i loved it! I always decant some of the DPX into a 100ml glass bottle, put in a plastic squeeze pipette and then screw a lid on it to stop it drying out (with the pipette still inside) when not in use. Surprisingly the pipette doesn't melt! Which is good because I am a recycle freak and i couldn't stand using a new one every time I mounted something!


Caroline Miller (mills)
Director of Histology
3Scan, Inc

> On Jul 10, 2015, at 10:55 PM, John Kiernan <jkiernan at uwo.ca> wrote:
> DPX is a polystyrene mounting medium. In principle you can make your own from published recipes. In practice, everyone buys commercial resinous mounting media.
> In the 1990s we had trouble similar to what you describe. The commercial DPX was cloudy, and not because of alcohol in our xylene. The Canadian supplier acknowledged the bad DPX and urged us to buy Entellan instead. Entellan is a poly(methacrylate) plastic and is an excellent but expensive mounting medium. Another poly(methacrylate) mountant called CytoSeal was less expensive and also came in a squeeze-easy plastic bottle for delivery onto the slide or coverslip. It's now my routine resious mountant. 
> Good DPX returned to the market in the 2000s, but in old-fashioned bottles and not easy to apply to slides or coverslips. 
> John Kiernan
> = = =
>> On 09/07/15, Adam Boanas  <a.boanas at epistem.co.uk> wrote:
>> Hello,
>> We are having a problem that is developing into a big issue in our lab and I was wondering if anybody could shed any light on it. Our CV5000 coverslipper has recently started introducing microscopic air bubbles onto the slides during coverslipping. We have been told by our engineer that it is a consequence of the age and use of the motor and that sourcing another for an instrument that old (15yrs) will be v difficult. As such, we have been forced to manually coverslip using DPX and a pipette - manually applying the coverslips to the slide, thus mirroring the action of the coverslipper. This is fine at first and for the next few days the slides look great and very clean. However, after about day 4 -5 days post coverslipping, the slides develop an odd appearance down the microscope which looks like very fine `parched earth / crazy paving` all over the slide - including the section. The excess mountant around the edge of the coverslip also has a very faint, cloudy appearance wh!
>>  en this occurs. This of course renders the slide un-useable. Does anyone have a clue what this might be down to / how we can stop it?
>> We are struggling for ideas with this one! - this occurs with fresh DPX also.
>> Many thanks
>> Adam
>> Adam Boanas
>> Senior Research Associate
>> Epistem Ltd
>> 48 Grafton Street
>> Manchester, M13 9XX
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