Thanks- the shrink problem on frozen sections--By low temperature of liquid N2?

From:yichao wu

Dear Margaret,

It is very nice to receive your email! Thank you for your kind suggestions.I 
will certainly get much help from it,really.

And it is very nice to know your experience of cruising down the Yangtsee 
River.That is really wonderful :-) I wish someday you could travel to this 
old city again.

Have a nice weekend!


>From: "Margaret Blount" 
>To: "yichao wu" 
>Subject: RE: Thanks- the shrink problem on frozen sections--By low 
>temperature of liquid N2?
>Date: Wed, 2 Jul 2003 14:20:36 +0100
>Dear Yichao,
>I always used to open my bottle in the fume hood, but once I had dispensed
>enough, I used it in the lab. Of course you should  make sure that there 
>no naked flames in the lab, no bunsen burners, etc. I used to dispense just
>enough into a small reagent bottle to keep for routine use and never had 
>problems with explosion or fire. As you say, it should be OK to freeze such
>a small sample embedded in OCT directly in liquid N2. I just thought that 
>experiences of isopentane might help. Good luck.
>Sorry to hear that your summer isn't so good this year. I particularly
>enjoyed the boat ride on the canal. But I also had the privelege of 
>down the Yangtsee river before the dam was completed and was very impressed
>with the work in  progress in building the dam. I enjoyed the whole of my
>visit to China and the Chinese people were very welcoming to us.
>Best wishes
>Margaret (not Dr I'm afraid, just Miss!)
>-----Original Message-----
>From: yichao wu []
>Sent: Wednesday, July 02, 2003 2:24 AM
>Subject: Thanks- the shrink problem on frozen sections--By low
>temperature of liquid N2?
>Dear Dr. Blout,
>Thank you so much for your suggestions.Actually I have learned such
>suggestion of using isopentane cooled by LN2 instead of LN2 directly. But I
>am worried about the safty of isopentane.I have not any kind of experience
>of it.And it is said to be easy to explode.
>How should I use it safely.In what temperature? Does it safe to open the
>bottle of isopentane directly in lab room at room temperature?
>Thank you very much! BTW,I used kidney biopsy specimens.I just wonder if it
>is somewhat acceptable to freeze such a tiny tissue embeded in OCT directly
>in liquid N2?
>And it is very nice to know you once travelled to my city.It has a cool
>summer this year.
> >From: Margaret Blount 
> >To: yichao wu ,
> >CC:
> >Subject: RE: still the shrink problem on frozen sections--By low
> >temperature of liquid N2?
> >Date: Tue, 01 Jul 2003 09:08:57 +0100
> >
> >Dear Yichao Wu,
> >
> >May I suggest that you freeze your samples in Isopentane cooled over 
> >nitrogen, it is better than using liquid nitrogen direct as the nitrogen
> >boils and produces a layer of nitrogen gas around the sample which slows
> >the
> >cooling. Suspend a plastic or metal beaker (about 100ml size) over the
> >liquid nitrogen, half fill it with Isopentane (2-methyl butane) then 
> >it gently into the liquid nitrogen. The liquid nitrogen will boil as you 
> >this so be very patient and slowly lower the beaker until it is
> >sufficiently
> >surrounded by nitrogen to cool the contents without being swamped. Allow
> >the
> >isopentane to freeze completely and raise it above the level of the 
> >You can then freeze your samples in the isopentane liquid generated as it
> >thaws, making sure that there is always some frozen isopentane in the
> >bottom
> >of the beaker to ensure that it is still cold enough. I always suspend 
> >beaker for the isopentane from a retort stand so that I have both hands
> >free
> >to handle my specimens. I hope I have explained this clearly, it is alway
> >easier to demonstrate this method.
> >
> >Good luck. By the way I visited Nanjing some years ago as a tourist and
> >very
> >much like the city.
> >
> >Regards
> >
> >Margaret Blount
> >Dept of Clinical Biochemistry
> >University of Cambridge
> >UK
> >   -----Original Message-----
> >   From: yichao wu []
> >   Sent: Tuesday, July 01, 2003 6:29 AM
> >   To:
> >   Cc:
> >   Subject: still the shrink problem on frozen sections--By low 
> >of liquid N2?
> >
> >
> >
> >
> >
> >
> >   Dear Tony,
> >
> >   Now I take back fresh biopsy specimen and incubate immediately in 
> >N2.Then section at -20C.It has better morphology.
> >
> >   But I find there is little space in the Bowan's Capsule.That is to 
> >the glomeruli still shrink much,therefore the space in between the
> >capillaries and the capsule around it decreased.
> >
> >   I wonder if the very low temperature causes the space to disappear? 
> >long should I put the specimen in liquid N2?
> >
> >   Thank you very much!
> >
> >   Yichao WU
> >
> >   Jinling Hospital,Nanjing,China
> >
> >
> >
> >
> >
> >
> >
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