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Very odd abstract found. Any comments?

Excelife excelife at earthlink.net
Wed Sep 9 22:20:30 EST 1998

In article <35f71d5b.28673484 at nntp.ix.netcom.com>, ufotruth at ix.netcom.com 
>I found the following abstract on the web. I was wondering if anyone
>had any comments about it. From everything I have read before it
>seemed like it had been proven that cells taken from younger
>individuals did indeed divide more times than cells from older
>Could the experiment mentioned in the following abstract be flawed or
>in error? Hey, it might be for real but it seems to me that it has
>already been tested many times that cells from younger people divide
>more times than from older people....
>Anyway.. Here is the abstract.
>Best Regards,
>Vol. 95, Issue 18, 10614-10619, September 1, 1998
>Cell Biology
>Relationship between donor age and the replicative lifespan of human
>cells in culture: A reevaluation 
>(cell proliferation/cell senescence/aging) 
>Vincent J. Cristofalo*,<Picture: dagger >, Robert G. Allen*, Robert J.
>Pignolo*, Bernard G. Martin*, and Jeanne C. Beck<Picture: Dagger > 

One particular study comes to mind that doesn't contradict these findings but 
does provide an explanation for them.

In this study it shows that telomeric loss is not consistent over the course 
of aging.  Telomeric loss is related to cellular growth rates that vary in 
the course of development and it would not be unexpected that replicative 
life span of cells from persons of diverse ages might be similar. 

Proc Natl Acad Sci U S A 1998 May 12;95(10):5607-5610

The rate of telomere sequence loss in human leukocytes varies with age.

Frenck RW Jr, Blackburn EH, Shannon KM

Clinical Investigation Department, U.S. Naval Hospital, Oakland, CA 94627,
University of California, San Francisco, CA 94143, USA.

A gradual loss of telomeric repeat sequences with aging previously has been
noted in normal adult tissues, and this process has been implicated in cell
senescence. No data exist that address the rate of telomere shortening in
normal human cells within families or early in life. To address these
questions, we measured telomere lengths in peripheral blood leukocytes
(PBLs) from 75 members of 12 families and in a group of unrelated healthy
children who were 5-48 months old. Here we report the surprising
observation that rates of telomere attrition vary markedly at different
ages. Telomeric repeats are lost rapidly (at a rate of >1 kilobase per
year) from the PBLs of young children, followed by an apparent plateau
between age 4 and young adulthood, and by gradual attrition later in life.
These data suggest that the loss of telomeric repeats in hematopoietic
cells is a dynamic process that is differentially regulated in young
children and adults. Our results have implications for current models of
how telomeric sequences are lost in normal somatic cells and suggest that
PBLs are an excellent tissue to investigate how this process is controlled.


Thomas Mahoney, Pres.
Lifeline Laboratories, Inc.

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