Re: [=LONGEVITYru=] Человечеству подарили бессмертие?!?
Привет всем!
в родственной рассылке http://groups.yahoo.com/group/h-longevity/
прошло сообщение о серьёзном открытии британских учёных.
некоторые журналисты даже поспешили сообщить, что открыт секрет бессмертия.
суть в том, что найден белок способствующий восстановлению теломеров. сокращение
теломеров считается одной из причин ведущих клетку к старению.
однако, уже доказано неоднократно, что только с помощью надстройки теломеров
старение не остановить, хотя мышам, по-моему, продлевали жизнь на треть. также
добивались омоложения сердечной мышцы.
так что увы, не смотря на всю важность открытия - это ещё не бессмертие :(
ниже два текста: русский и английский
в английском тексте акценты расставлены вернее.
С уважением, Рязанов Дмитрий.
Продление жизни, научный иммортализм и трансгуманизм.
www.bessmertie.ru www.transhumanism.ru Dmit***@b*****.ru
Источник: http://www.medicalnewstoday.com/index.php?newsid=7818
New clues to the secret of eternal life
30 Apr 2004
SOME OF the mystery surrounding ageing, death and cancer is dispelled tomorrow
(Friday) by a major new study in the premier journal Cell*.
Scientists from Cancer Research UK and Breast Cancer Campaign have uncovered
the first evidence of an entirely new system for holding the ravages of time
at bay.
The system involves adding thimble-like caps to the ends of chromosomes in order
to protect DNA from damage and slow the ageing process.
Cancer cells may rely on DNA capping for their remarkable ability to grow and
divide eternally - ignoring the normal constraints on lifespan. The discovery
could provide a new route of attack for up to 10 per cent of tumours.
Each human cell has an inbuilt timer to ensure it lives as long as necessary
and no longer. Attached to the ends of the chromosomes (the packages of genetic
material within cells) are repetitive strips of DNA called telomeres. These get
shorter each time a cell divides until there is nothing left - and the cell knows
it is time to die.
But cancer cells are immortal - they are able to reset or stop their timer, giving
them unlimited lifespan. Many cancer cells do this by using an enzyme called
telomerase to rebuild their telomeres, but researchers knew this couldn't be
the only culprit, since cancer cells can achieve immortality without it.
In the new study, scientists at the Cancer Research UK London Research Institute,
with additional funding from Breast Cancer Campaign, investigated how else cancer
cells might subvert the natural ageing process.
They used a technique called immunofluorescence to light up various molecules
within cancer cells and see precisely where they were operating. One particular
molecule, called RAD51D, appeared time and again at the site of the telomeres,
suggesting it was interacting in some way with the timer mechanism.
When researchers blocked the activity of RAD51D using a second technique called
RNA interference, they found substantial damage to the telomeres and other parts
of the genome - the telltale signs of accelerated ageing.
RAD51D is known to play a role in repairing DNA, but the authors suggest that
is has a second role - as supplier of a protective cap for the telomeres.
Dr Madalena Tarsounas, leading the study at the Cancer Research UK London Research
Institute and funded by both Breast Cancer Campaign and Cancer Research UK, says:
"Cancer has an amazing ability to shake off the shackles of ageing and death,
which is one of the reasons why it can be so hard to treat.
"Understanding how cancer cells remain eternally young has been a key focus of
research for more than a decade, so it's particularly exciting to have made such
a striking discovery.
"We have found evidence of a completely new mechanism for stopping the clock
on a cancer cell's timer and preventing its lifespan from ticking down. It raises
the possibility of starting the clock again and making cancer cells susceptible
to death once more."
Having a stable telomere is important to prevent a cell's genetic material from
becoming unstable. Researchers believe that in normal cells, RAD51D may stabilise
the telomeres without interfering with the timer that limits their lifespan.
But in cancer cells RAD51D may be over-active, stopping the clock and allowing
the cells to grow and divide indefinitely.
Drugs to block the action of RAD51D could potentially be effective against many
different tumours, by stripping cancer cells of their immortality.
Dr Tarsounas adds: "We think as many as 10 per cent of tumours may be heavily
reliant on the new mechanism to keep their cells alive and these may also be
highly susceptible to drugs targeted against it.
"As well as opening the way to new types of treatment for cancer, our study has
shed light on the complex but intriguing processes which control how and when
we get old."
Pamela Goldberg, Chief Executive of Breast Cancer Campaign, says: "By avoiding
one of the normally inescapable cell mechanisms, cell death, cancer cells are
able to have unique control in the human body.
"This research has discovered an important element which appears to be essential
in sidestepping this cell death process and if we can in some way control this
we may be able to stop the growth and spread of cancer cells."
Professor Robert Souhami, Cancer Research UK's Director of Clinical and External
Affairs, says: "Ageing, at least at a cellular level, isn't just a question of
running out of steam but a carefully planned process to keep the number of old
and new cells in balance.
"Cancer cells are adept at slipping the constraints of the ageing process, but
this highly significant study points to ways of making them mortal, and vulnerable,
once more."
* Cell, Vol. 117, 337-347, April 30, 2004
Media contact
If you would like to get in touch with the Cancer Research UK press office, please
go to our contacts page at:
http://www.cancerresearchuk.org/news/contacts/
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Более подробная информация по этой теме есть на странице
http://www.grani.ru/Society/Science/m.68983.html
Там рассказывается что раковые клетки бессмертны не только из-за синтеза
теломеразы, но и за счет восстановления теломеров белком RAD51D.
Да кстати я таки купил наконец нооклерин. Оказался таки в одной аптеке
нашего города.
Original Message From: "Дмитрий А. Рязанов" <Dmit***@b*****.ru>
To: "science.news.bessmertie (4249009)" <avrel***@u*****.ru>
Sent: Monday, May 03, 2004 1:41 PM
бессмертия.
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