[Histonet] Isopentane

[Peggy Bisher]

Liquid nitrogen (-196C) and nitrogen slush (-207) are the coldest cryogens
used, but they have the slowest freezing rates. The most effective cryogens
are those that are those that stay a liquid when cooled almost to the
temperature of liquid nitrogen.

Propane (-189.6C mp) or Ethane (183.5C mp) is the cryogen of choice that we
use for cryo electron microscopy.


Margaret E. Bisher
Electron Microscopy & Histology Core Facility Manager
Department of Molecular Biology
Princeton University
Moffett Laboratory, Room 113
Princeton, New Jersey
Office: (609) 258-7026
Fax: (609) 258-8468
mbisher <@t> princeton.edu






On 12/16/08 10:02 PM, "Tony Henwood" <AnthonyH <@t> chw.edu.au> wrote:

> Depends on how you freeze.
> When we freeze tissue in liquid nitrogen, the tissue is shaken, ensuring
> that the gas layer is broken up.
> And in so doing we have not seen evidence of ice crystal formation.
> 
> I can send you a reprint of a paper that describes the effect of storage
> of brain tumours in saline prior to freezing (causing much distortion of
> the tumour) verses receiving the samples fresh on damp gauze or card.
> The pics show the evidence.
> 
> Henwood, A., (2007) "Adverse effect of saline on brain intraoperative
> (frozen section) Histology" J Histotechnol 30(3):193
> 
> Regards
> 
> Tony Henwood JP, MSc, BAppSc, GradDipSysAnalys, CT(ASC)
> Laboratory Manager & Senior Scientist
> Tel: 612 9845 3306
> Fax: 612 9845 3318
> the children's hospital at westmead
> Cnr Hawkesbury Road and Hainsworth Street, Westmead
> Locked Bag 4001, Westmead NSW 2145, AUSTRALIA
> 
> 
> 
> 
> -----Original Message-----
> From: Markus F. Meyenhofer [mailto:micro <@t> superlink.net]
> Sent: Wednesday, 17 December 2008 1:47 PM
> To: Tony Henwood; Dana Settembre; carmen loiselle; pathology education
> Subject: Re: [Histonet] Isopentane
> 
> 
> Isopentane is cooled by liquid N2!
> To freeze tissue direct in LN2  is not the best way to freeze tissue due
> to 
> the Leidenfrost effect, creating an insulating gas layer between the
> tissue 
> and the liquid and delaying the speed of freezing = an increase in ice
> crystal formation.
> Regards,
> Markus F. Meyenhofer
> 
> ----- Original Message -----
> From: "Tony Henwood" <AnthonyH <@t> chw.edu.au>
> To: "Dana Settembre" <settembr <@t> umdnj.edu>; "carmen loiselle"
> <carmen_loiselle <@t> hotmail.com>; "pathology education"
> <histonet <@t> pathology.swmed.edu>
> Sent: Tuesday, December 16, 2008 6:19 PM
> Subject: RE: [Histonet] Isopentane
> 
> 
> Try liquid nitrogen
> 
> Regards
> 
> Tony Henwood JP, MSc, BAppSc, GradDipSysAnalys, CT(ASC) Laboratory
> Manager & Senior Scientist
> Tel: 612 9845 3306
> Fax: 612 9845 3318
> the children's hospital at westmead
> Cnr Hawkesbury Road and Hainsworth Street, Westmead
> Locked Bag 4001, Westmead NSW 2145, AUSTRALIA
> 
> 
> 
> 
> -----Original Message-----
> From: histonet-bounces <@t> lists.utsouthwestern.edu
> [mailto:histonet-bounces <@t> lists.utsouthwestern.edu] On Behalf Of Dana
> Settembre
> Sent: Wednesday, 17 December 2008 5:27 AM
> To: carmen loiselle; pathology education
> Subject: Re: [Histonet] Isopentane
> 
> 
> Hello Carmen,
> Sorry I have no alternative.  I know most labs use that.
> When I worked in a neuropathology lab the isopentane was kept in the
> refrigerator - an explosion proof one. I believe that means there's no
> lightbulb inside and no inner working of a lightbulb inside either.
> 
> 
> Dana Settembre, HT ASCP
> Immunohistochemistry Lab
> UMDNJ - University Hospital
> Newark, NJ    USA
> 
> 
>>>> carmen loiselle <carmen_loiselle <@t> hotmail.com> 12/16/08 12:24 PM
>>>> 
> 
> Hello ,
> 
> I currently work in a neuromuscular lab and all muscle biopsies received
> should be cut frozen, no formalin fixed tissues.  My concern though, is
> to work with isopentane , a well known excellent heat conductor but also
> it has the bad reputation of being very explosive. In fact , I've been
> told that few years ago, a lab close by of where I work , did explode
> because of this solution.  Is there , in your knowledge, any other
> chemical we can use as replacement and that give as good results.
> 
> Any input will be greatly appreciated
> 
> Merry XMas to all and happy New Year
> _________________________________________________________________
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