Olivier Gandrillon Olivier.Gandrillon at
Mon Oct 19 03:56:55 EST 1998

Dear Dr Shapiro

Dedifferentiation is a concept that I personnally have never seen ANY 
solid evidence of. As I understand it, to prove its existence, you would 
have to start from ONE cell, verify its differentiated characteristics, 
and THEN try to make it become something else. ALL of the evidences that 
rely on cell POPULATIONS are NOT convincing  for me because how would 
you exclude that there is in the population a very small number of 
bipotent cells that can alternatively generate two final ligneages?

Olivier Gandrillon

Dr. S. Shapiro wrote:
> Dear Colleagues;
>         I am seeking information about a mammalian (human?) tissue
> that is capable of de-differentiating and then giving rise to a new dif-
> ferentiated tissue.  The only thing I can think of offhand is the liver.
> It is my understanding that the liver consists of a large variety of highly
> differentiated cells.  Yet, when as much as 90% of the liver is surgically
> removed, the remaining 10% of this organ can regenerate the entire
> liver in a relatively short time.  Does this mean that some of the remain-
> ing liver cells can de-differentiate into pluripotent or totipotent cells and
> subsequently re-differentiate into the desired liver cells during the course
> of liver regeneration?  I am not a medical doctor or mammalian physiologist/
> pathologist, and haven't studied these things for some 30 years, so perhaps
> someone who is a little more up to date can advise me on this?  Please
> give references where available.
>         Also, I would like information about other(?) mammalian tissues
> that are capable of de-differentiating and then re-differentiating.  Of course,
> references are crucial.
>         Responders are kindly requested to contact me directly at
>                 toukie at
> Thanks in advance to all responders,
> S.  Shapiro
> toukie at

Dr O. Gandrillon
Département de biologie
Ecole Normale supérieure de Lyon
46, allée d'Italie
69364 Lyon Cedex 7
Phone: 04-72-72-86-15
Fax: 04-72-72-86-86
E.mail: ogandril at
"The reasonable man adapts himself to the world; the unreasonable one 
persists in trying to adapt the world to himself. Therefore, all 
progress depends on the unreasonable man."
George Bernard Shaw

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