Fixation --- Labeling ONLY surface molecules

JOHN BOUCHER jbouch at
Fri Feb 15 20:20:22 EST 2008

Elise, you took the words right out of my mouth.  I ,too, need to  
find a technique for overcoming the membrane leakiness caused by  
fixing RBCs (glutaraldehyde or formaldehyde) in order to label only  
surface molecules.

Improving the fixation technique to prevent/inhibit membrane pores,  
OR, "building" a fluorescent label larger than the pores so that they  
won't penetrate the membrane is a long sought goal.

Please, please, if someone answers you with a miracle answer, I'd  
appreciate knowing.

A couple of months ago, Vicki Singer (Invitrogen)  
(<vicki.singer at>) notified me that Invitrogen might be  
interested in looking into a solution for "getting around" the	
leakiness of cell membranes caused by fixatives.  If Vicki is  
listening, I hope she'll let us know the status of Invitrogen's  
possible solution.

John H. Boucher, DVM, PhD
Rheotech Labs, Inc.
Comparative Studies in Blood Rheology
2106 Salisbury Road
Silver Spring, MD 20910, U.S.A.
Phone:	301-585-1885
Email:	<jbouch at>
On Feb 14, 2008, at 5:01 PM, Palmer, Elise wrote:
> Hi,
> I was wondering if anyone has experience assessing apoptosis with  
> annexin V and 7AAD, and fixation?
> I need to run some HIV patient samples so they have to be fixed. I  
> will be looking at lymphocytes. I have had no success finding  
> anything in the literature in which both annexin V and 7AAD were used.
> I would really appreciate any ideas or help you can give me!
> Elise (University of Rochester Medical Center)

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