Dear Jean,

   Despite  previous  posts on this subject, to my opinion using paraffin
   sections as positive control along with cytology cytospin preps is not
   such  a  good  idea! That  also  accounts  for paraffin  cytoblocks as
   positive  control.  I  do understand that finding appropriate positive
   controls here isn't easy from practical point of view.

   My  point is that a cyotology cytospin prep consists of cells that are
   (more   or  less)  intact  with an outer  membrane,  whereas  paraffin
   sections from tissue or cytoblocks contain cut-open cells and no outer
   membrane.  We  have observed  here  quite dramatic differences between
   intact  cells  and cut-open cells when performing IHC techniques. This
   has  everything  to  do  with  the  cellular outer membrane as barrier
   for your  antibodies. I  think  that  immunostaining of  intact cells,
   needs  intact  cells  as  positive  control.  And,  immunostaining  of
   sections, needs sections as positive control. Having said that, I also
   think   we   have   to   go   back   to   the   original  terminology:
   "immunocytochemistry"  for cells and "immunohistochemistry" for tissue
   sections. Mixing up those terms long time ago was a pretty bad idea.

   Chris van der Loos, PhD
   Dept. of Pathology
   Academical Medical Center M2-230
   Meibergdreef 9
   NL-1105 AZ Amsterdam
   The Netherlands

   phone:  +31 20 5665631
   fax:    +31 20 6960389


   Date: Tue, 19 Jul 2005 15:40:51 +0100
   From: Jean Gillson 
   Subject: [Histonet] Cytology Immuno's
   To: "'histonet@lists.utsouthwestern.edu'"
   
   Can  I  ask  you  all,  what  do you use as controls when doing ICC on
   cytology
   cytospin preps or smears?  Since there isn't much sample, do you use
   paraffin sections as positive controls and is that adequate control
   measures?   We  currently only use paraffin cytoblocks but considering
   ICC on
   thin layer cytology preps and wondering what control material to use.
   Thanks for your help.
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