[Histonet] DRGs histogel

Tue Feb 23 12:53:19 CST 2010

  I think dehydration during processing can effect the outcome with histogel. I use it frequently to help orient small samples with very good results almost always. 

One time, I was trying to arrange several samples in the same block and the histogel got too cold and set up when I was partly finished. I put it all in our oven hoping to remelt it. When I took it out, it had become a hard thin sheet, sort of like dried paint or glue. The only thing I could think of that had happened, was that since it was in a shape with a lot of surface area, it had dried out instead of melting. I wanted to save the sample that was in it, so I added some water. Thankfully, the histogel became gel like again and I was able to find the sample which I transfered to fresh histogel. The reconstituted histogel seemed to be the same as regular histogel, excep it lost its pink color. The samples also were ok.

 I've never had any real problems cutting histogel (and hope I don't), but if I get one that is a little crumbly, I soak it extra long and that helps. I think that maybe when there are inconsistent results with histogel, maybe something happens during processing so it becomes dried out or overly dehydrated.  I have used it both out of formalin and out of 70%. I've also embedded it both wet and dry without problems. Sometimes it is whiter than others.

Karen Doty

> Date: Mon, 22 Feb 2010 09:35:10 -0800
> From: dunatrsd <@t> sbcglobal.net
> To: portera <@t> msu.edu; algranth <@t> email.arizona.edu; histonet <@t> lists.utsouthwestern.edu
> Subject: Re: [Histonet] DRGs
> CC: 
> 
> I also think that it is strange of the way Histogel processes. I have posted on the Histonet previously about this exact problem. I worked with Jennifer Hofecker when she was at Vanderbilt U.(sent her my Histogel and she sent me hers) and ended up with perfectly processed Histogel blocks at our facility and hers. I processed a couple of blocks last week and they were just terrible. No change in the processing schedule, or the way Histogel was liquefied (placed in hot water that was heated in the microwave). Prior to the last two blocks, I must have processed at least a dozen blocks without any problems. There was an incident where I placed two histogels in the same cassete. One processed beautifuly and the other was all shrunken and dried up.
> I do not liquefy the entire tube, rather I scoop out the approximate amount that I need and transfer to another tube to heat up. If there is anyone out there in Histoland that has not had any issues with the Histogel, can you please post your procedure on liquefying the Histogel, method of cooling/solidifying and processing schedule? The only thing that I do that is not exact is I do not know the temp of my hot water when i place the Histogel to liquefy. I basically have to wait several minutes for the gel to melt and I use it immediately.
> Any new information or solution from anyone, would be greatly appreciated.
> Thank you
> Dusko Trajkovic
> 
> 
> 
> ________________________________
> From: Amy Porter <portera <@t> msu.edu>
> To: Andrea Grantham <algranth <@t> email.arizona.edu>; HISTONET <histonet <@t> lists.utsouthwestern.edu>
> Sent: Mon, February 22, 2010 9:01:22 AM
> Subject: RE: [Histonet] DRGs
> 
> I think it is strange that we are all doing similar techniques and wind up
> with different outcomes using the histogel.  I would be curious how many of
> us are using the equipment sold with the histogel for warming and cooling
> opposed to any of us who don't.  we did not purchase the equipment and I
> wonder sometimes if warming the histogel using other means causes some type
> of breakdown / and do any of you repeatedly reheat the same tube once it has
> been warmed and resolidified??
> 
> -----Original Message-----
> From: histonet-bounces <@t> lists.utsouthwestern.edu
> [mailto:histonet-bounces <@t> lists.utsouthwestern.edu] On Behalf Of Andrea
> Grantham
> Sent: Monday, February 22, 2010 9:41 AM
> To: HISTONET
> Subject: Re: [Histonet] DRGs
> Importance: High
> 
> Hi Carol,
> I have used histogel for these kinds of samples and also other small,  
> thin tissues like insect antennae and insect GI tracts and midguts.  
> Since I get all my projects already fixed in whatever fixative the  
> investigator chooses, rinsed and placed in 70% ETOH the histogel never  
> touches formalin. I don't use formalin on my processor but start in  
> 70%. I've never had a problem with the histogel. We just put the  
> sample in the histogel flat and stand it up (turn 90°) when embedding  
> in paraffin. I use tissue prep for embedding.
> If you don't want to use histogel you could try to put the drg's on GN  
> Metricel membrane disc filters. We do this with a lot of the samples I  
> receive, actually I have the investigators or their techs do this. The  
> tissue sticks to the membrane and orientation is a dream. The membrane  
> presents no problem when sectioning. You can get it from VWR.
> 
> Andi
> 
> 
> 
> Andrea Grantham, HT (ASCP)
> Senior Research Specialist
> University of Arizona
> Cell Biology and Anatomy
> Histology Service Laboratory
> P.O.Box 245044
> Tucson, AZ 85724
> 
> algranth <@t> email.arizona.edu
> Tel: 520.626.4415    Fax: 520.626.2097
> 
> "happy slicing and dicing and may all your stains work perfectly" -  
> Paula Sicurello
> P Please consider the environment before printing this email.
> 
> 
> 
> 
> On Feb 18, 2010, at 11:23 AM, Barone, Carol wrote:
> 
> > Histonetter's...we received a "boat-load" of mouse DRGs that had been
> > prepared in histogel and are cutting...well..not so good.
> > We normally do DRGs from FS and get beautiful results.
> >
> > We have used histogel before with other small sample and have never  
> > had
> > issues...  not sure if it is the Histogel or DRG's (fixed in 10% NBF  
> > and
> > then transferred to 70% before placed into the histogel).is the  
> > issue..I
> > seem to remember that histogel requires formalin and wonder if the
> > transfer to 70% is causing our problem ...but, obviously there is not
> > much room for error with such tiny- tiny samples and they are already
> > process and in paraffin?
> >
> > I am not quite sure how twe can improve the ones that came in  
> > histogel,
> > and were processed to paraffin a paraffin block....any idea's? any
> > experience? any anything? Thx- ASAP!
> >
> > cbarone <@t> nemours.org
> > _______________________________________________
> > Histonet mailing list
> > Histonet <@t> lists.utsouthwestern.edu
> > http://lists.utsouthwestern.edu/mailman/listinfo/histonet
> >
> 
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