Hello Mark

"TUNEL" stands for:  Terminal deoxynucleotidyl transferase mediated dUTP
nick end labeling.   The assay enzymatically labels the free 3'OH ends of
DNA independent of template.  In the later stages of apoptosis, DNA cleavage
occurs producing ~800 bp fragments.  The free 3'OH ends are the target your
trying to label to demonstrate apoptosis.  However other processes,  namely
necrosis,  can also produce fragmented DNA.  In fact, harsh treatment of
slides can also induce strand breaks that can be labeled by the TUNEL assay;
so one must use extreme care when interpreting the results.  When we
interpret our TUNEL,  we use the morphological characteristics of apoptosis
as well.

Hope this helps
Luis

--------------------------------------

-----Original Message-----
From: mark.lewis@thermo.com [mailto:mark.lewis@thermo.com]
Sent: Thursday, September 05, 2002 10:21 AM
To: histonet@pathology.swmed.edu
Subject: What is a Tunnel stain


Hello everyone,

Could someone please explain to me what a Tunnel stain is Is it to show
apoptosis ?   Any info would be appreciated

Thanks !


Best regards,

Mark

Mark Lewis
Product Specialist
Thermo Shandon
171 Industry Drive, Pittsburgh, PA 15275 USA
Direct: (412) 747-4013
Fax: (412) 788-1097
E-mail: mark.lewis@thermoshandon.com

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