X-Message-Number: 8152
From:  (Randy)
Subject: CRYONICS Repair/regrowth of body parts
Date: Tue, 29 Apr 1997 22:41:46 GMT

Here are a couple of excerpts from an article
By Nigel Hawkes, the Times of London about how some scientists are
working on genetic switches that may give us the ability to
regrow/replace missing/damaged body parts.

If a small breakthrough in this area were to occur, it may help people
see the potential of cryonics by pointing the way to possible revival
scenarios.

Excerpt 1:
>>
 Lose an arm and you'll never grow another one. That may seem obvious,

but all the original genes which instructed the first arm to grow are=20
still there and, in theory, available for service.

Turning them on again and enabling the body to rebuild itself after=20
accident or disease has become the target of ambitious developmental=20
biologists. They dream of reconstructing bones damaged by
osteoporosis,=20
or persuading the heart to build new muscle after a heart attack.

"The whole circuitry is there, ready to go," says Dr. Doros Platika,=20
president and chief executive of Ontogeny, a biotech company in=20
Cambridge, Massachusetts
>>
excerpt 2
>>

"What we are aiming to do=20
is to revive capabilities that are lying dormant. If we can, we should

be able to treat a number of degenerative diseases, from osteoporosis
to=20
Alzheimer's." Dr. Platika's optimism is based on the huge progress
made=20
in the past ten years in understanding the process by which the single

cell of a fertilised egg develops into the multiplicity of organs of
the=20
human body. This process, akin to a miracle, appears to use exactly
the=20
same mechanisms required in adults for growth, tissue regeneration and

repair.

The trouble, explains Dr. Platika, is that as we age, we lose the=20
capability to turn on repair mechanisms. Operations on adults
generally=20
leave a scar, but operations carried out in the womb heal so perfectly

that it is impossible to tell they have taken place.

In adults, the ability to regenerate organs is not lost: blood, bone,=20
and many other organs are constantly being remade. The process is not=20
universal, however. When a coronary artery is blocked, the body does
not=20
have the ability to create another one. But when a solid tumour
develops=20
anywhere in the body, it needs blood vessels to feed it, and they are=20
created in great numbers. This shows, says Dr. Platika, that the
ability=20
to create new organs is not lost in adults, but merely latent. Provide

the right circumstances and it can be triggered back to life.

That answer, Ontogeny believes, is based on a family of proteins
called=20
Hedgehog.
>>
excerpt 3
>>

Since then, several more Hedgehog genes have been found. Dr. Philip=20
Ingham, of Sheffield University and a member of Ontogeny's scientific=20
advisory board, was responsible with others for showing that higher=20
animals have three Hedgehogs, called equally quaintly Sonic hedgehog,=20
Indian hedgehog, and Desert hedgehog. (Conventionally, genes are given

italics to distinguish them from the proteins they make, which are=20
printed in roman script.)

Sonic hedgehog has several roles, including the creation of cells in
the=20
brain and central nervous system. Indian hedgehog is expressed in the=20
limbs, directing the development of bone and cartilege, while Desert=20
hedgehog drives the development of male sperm. The belief is that
there=20
are limited numbers of Hedgehogs -- probably no more than three or
four=20
in humans, in which case it is possible that all of them have been=20
discovered.
>>
excerpt 4
>>

The embryologist Professor Lewis Wolpert, of University College
London,=20
is sceptical that things will prove as simple as Ontogeny and its=20
partners hope. He suspects that clinical applications remain a long
way=20
off, if only because the process of signalling involves not just the=20
Hedgehogs, but many other "inducing molecules" that are triggered in a

cascade.

Hedgehogs are signalling molecules," he says, "but I would be very=20
surprised if the problem in most diseases is in the signal, rather
than=20
the response. My reason for believing that is quite simple. If
diseases=20
were caused by deficiencies in Hedgehog, then you wouldn't expect just

one thing to go wrong, but lots of things."

Dr. Platika acknowledges that there may be dozens of genes
orchestrated=20
by Hedgehog, and the company has developed a neat system for
discovering=20
them. The ability of geneticists to identify genes has outstripped
their=20
ability to discover exactly what they do. Ontogeny has developed a=20
screening system, which enables candidate genes to be tested, and to=20
discover if they have any function in the development process.
>>
end of excerpt 4

Randy  =20
Cryonics: Gateway to the Future?
http://members.wbs.net/homepages/c/r/y/cryofan1.html            =20
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