Re: questions @ Tdt and DNA/cytokeratin

From: larry_seamer@bio-rad.com
Date: Tue Oct 07 1997 - 12:03:22 EST


     In response to Kathy Altig's last question.
     
     Bio-Rad Labs makes a DNA - Cytokeratin single-step kit called 
     Kinesis-CK. Basically it is PI and FITC labeled anti-cytokeratin with 
     the necessary ancillary reagents in single use vials, optimized for 
     flow cytometry. For more information you can call (800) 2-bio-rad.
     
     Larry Seamer
     Associate Product Manager/Flow Cytometry
     Bio-Rad Labs


______________________________ Reply Separator _________________________________
Subject: questions @ Tdt and DNA/cytokeratin 
Author:  <Kathy_Altig@phsor.org (Kathy Altig) > at Internet
Date:    10/6/97 2:17 PM


     
     My first question concerns Tdt by flow cytometry vs. Tdt by slide 
     (immunofluorescence).  I ran flow cytometry on a Bone Marrow aspirate 
     from a patient previously diagnosed with RAEB. The clinician's 
     supposition was that he was converting to leukemia.  The aspirate 
     contained a large group of cells that marked with CD33,CD34,MPO, (all 
     50%) and Tdt 50%.  The Wright's stained slide confirmed the presence 
     of some very ugly cells in a high proportion.  The pathologist writing 
     the interpretation wanted to check the Tdt (which didn't fit with her 
     probable interpretation) by slide.  I performed the slide Tdt, and the 
     cells "appeared " to be positive in the cytoplasm, not the nuclear 
     areas.  When I relayed this information, she felt that the flow Tdt 
     was not "real", and interpreted it as negative.
     
     Does this mean that Tdt by flow (we use the Tago Fix & Perm kit) is 
     not a reliable test, and we must do the slide test?  I must confess, 
     we hate doing the slide test;  and the flow test has seemed to be a 
     great est -- however we have not done the test by both slide and flow 
     methodologies many times.  We did a few times, in the beginning, then 
     after declaring the flow test good, we have done our best to avoid 
     doing the slide test.
     
     What does it mean if the Tdt appears to be "cytoplasmically" positive 
     on the slide?  
     
     My second question has to do with cytokeratin staining with DNA 
     analysis.  We have physicians requesting this for bladder washings, 
     paraffin prep.s and fresh frozen tumors.  I am in the process of 
     collecting procedures and anecdotal information.  Please send me 
     anything that would be helpful.
     
     Thank you!
     Kathy Altig
     Providence Portland Medical Center
     
     Kathy_Altig@ccmgate.phsor.org
     



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