X-Message-Number: 23881
From: "Mark Plus" <>
Subject: Military scientists to study regrowth of limbs 
Date: Tue, 13 Apr 2004 08:24:23 -0700

This has some bearing on the problem of constructing new bodies for 
cryonicists, especially neuros:




Mon 12 Apr 2004
Military scientists to study regrowth of limbs


HUMANS could eventually re-grow lost arms and legs if a pathfinding project 
launched by US military researchers proves successful.

The natural regeneration of limbs, which has fascinated scientists for more 
than 200 years, is seen as possible if the secrets of a similar process in 
amphibians can be deciphered.

The military research has been spurred by the need for potential treatments 
for the increasing numbers of soldiers with disfiguring injuries.

However, scientists who have long grappled with the problem believe the 
cloning of Dolly the sheep in 1996 and the first stem cell lines two years 
later have taken them significantly closer to their goal.

The United States  Defence Advanced Research Projects Agency (DARPA) is 
spearheading an initial  250,000 research project, codenamed ReGenesis, to 
investigate the potential of such work.

Dr Brett Giroir, the deputy director of DARPA s defence sciences office, 
said the ability to regrow severed limbs could follow on from studies into 
accelerating the healing of wounds and burns.

He told a conference in California last month: "This ability to regenerate 
limbs is present in many species, and even humans can regenerate a normal 
liver after removing as much as 90 per cent of it during surgery.

"So why can t this regenerative capability be available for human limbs or 
the brain and spinal cord?"

While flatworms, sea squirts, fish and amphibians can regrow internal organs 
and even entire limbs to varying extents, humans can fully regenerate only a 
very few tissues and organs, including the liver, the blood, and the 
outermost skin layer.

As children, humans can renew fingertips from the base of the nail upwards. 
But some scientists believe that growing a new finger could ultimately prove 
to be as simple as taking a pill, applying a drug-coated bandage or spraying 
liquid on to a freshly-damaged stump.

"This is doable - I believe it is inevitable that we will regenerate an 
entire human limb," Dr Ellen Heber-Katz, a biologist at the Wistar Institute 
in Philadelphia, told the Los Angeles Times.

The science behind the research dates back to 1768, when Lazzaro 
Spallanzani, an Italian monk, noted that amphibians could regrow their body 

One hundred years later, August Weismann, a German biologist, suggested that 
"ids" - or genes - provided the information which directed the body s 

He thought these progressively worked outwards, so cells at the elbow could 
construct a forearm, hand and fingers. In this way, he believed a stump 
should contain sufficient information for regrowing an arm or leg.

A further breakthrough came in 1976 when a group of American biologists 
found that when a salamander s leg was amputated, the nascent limb which 
started to grow in its place would prompt other limbs to grow on the 
amphibian s body if it was transplanted elsewhere.

However, some claim the science was transformed by the arrival of the 
world s most famous sheep, at the Roslin Institute in Midlothian.

"Dolly was the  Aha!  moment," Dr Gerald Schatten, a developmental biologist 
at the University of Pittsburgh, told the LA Times. "Most medical research 
viewed salamander regeneration as esoteric, but Dolly has changed the entire 
thinking about the plasticity of mammals, including humans."

The emergence of stem cells was seen as a further key step, since these 
offered the possibility of regenerating any other type of cell in the body.

However, researchers are still trying to establish the genetic signals which 
trigger the first steps towards regeneration.

Dr David Gardiner, a professor of developmental cell biology at the 
University of California at Irvine, who is experimenting with salamanders, 
believes there is a "signal and response" when wounds occur. Under this 
theory, when tissues are damaged in an amputation, cells at the site release 
signals to call in reinforcements.

Dr Gardiner is convinced that limb regrowth can be achieved because it would 
follow a similar process that is involved in a human embryo developing arms 
and legs for the first time.

But other scientists are sceptical about whether such research will ever 
lead to complete limbs being regrown.

Dr Bruce Carlson, of the University of Michigan, and a leading figure in 
regeneration research, believes the human body grows scars rather than new 
limbs to prevent it bleeding to death - and there is good reason for this 
natural defence mechanism.

Dr Jeremy Brockes, of the department of biochemistry at University College, 
is only marginally less sceptical.

He said: "The idea that you could make a complex structure like a limb seems 
at present quite fanciful."

However, he added: "I genuinely believe it is too difficult to say if it is 
impossible. There is no clear reason why, in principle, it should not 

Or, we could use the more direct approach pioneered by Dr. Vladimir Mironov. 
A year ago in "The Futurist" magazine, Mironov claimed that "organ printing" 
could in principle produce a functional adult human body in short order:

Organ printing: computer-aided jet-based 3D tissue engineering


"The Venturist," 2nd Quarter 2003 (scroll down to page 4):


Mark Plus

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