COULD gene therapy provide a
means of busting the plaques that
cause Alzheimer’s disease?
Alzheimer’s occurs when a
protein called amyloid-beta (Aß)
accumulates in the regions of the
brain concerned with memory
and thought. Existing therapies
treat the symptoms of the
disease but do nothing to target
this underlying cause.
Now, Matthew Hemming
and his colleagues at Harvard
Medical School in Boston have
used gene therapy to boost levels
of an enzyme called neprilysin in
through the body instead
of remaining bound to cell
membranes. “It allows the
enzyme to go to the sites of Aß
accumulation rather than just
sitting on the cell,” says Hemming
(PLoS Medicine, DOI: 10.1371/
journal.pmed.0040262).
The researchers now plan to
inject the cells into other parts of
the body, to see if neprilysin can
still reach the brain. The ultimate
goal is to incorporate the cells into
a small implant that could be
placed anywhere under the skin,
says Hemming.
mice with the equivalent of
Alzheimer’s. Neprilysin was
already known to degrade the
amyloid protein and its levels are
reduced in people with Alzheimer’s.
Hemming’s team took
fibroblast cells from the skin of
the mice and engineered them to
contain the gene for neprilysin.
When they injected these cells
into the hippocampus, nearby
plaques disappeared. Crucially,
plaques further away also
diminished. This is because the
gene had been altered to create a
form of neprilysin that can travel
Alzheimer’s plaques dissolve after gene therapy
A RARE edge-on alignment of
Uranus’s rings as seen from Earth
has revealed extensive changes
since the Voyager 2 probe
observed them in 1986.
Voyager 2 photographed
Uranus’s major rings, thought to
be made of chunks of rock, along
with some wispy dust rings. In
2003, the Hubble Space Telescope
revealed two new dust rings.
Imke de Pater of the University
of California, Berkeley, and her
team have now taken infrared
images of the dust rings using
the 10-metre Keck II telescope on
Mauna Kea, Hawaii. They found
that one dust ring seen by
Voyager 2, called the zeta ring,
seems to have disappeared
altogether, while a new one has
appeared in a zone that had
previously looked empty (Science,
DOI: 10.1126/science.1148103).
The changes reinforce the
emerging view that ring systems
are much more dynamic than
previously thought. “We used
to think it was like studying
geology,” says team member
Mark Showalter of the SETI
Institute in Mountain View,
California. “Now we’re learning
that studying them is more like
studying weather.”
Ringside view of change at Uranus
MEN hunted, women gathered. That is
how the division of labour between the
sexes is supposed to have been in the
distant past. According to a new study,
an echo of these abilities can still be
found today.
Max Krasnow and colleagues at the
University of California, Santa Barbara,
have discovered that modern women
are better than men at remembering
the location of food such as fruit and
veg in a market.
The researchers led 86 adults to
certain stalls in Santa Barbara’s large
Saturday farmer’s market, then back to
a location in the centre of the market
from where the stalls could not be seen.
They were then asked to point to each
stall’s location. This requires dead
reckoning – a skill that men may once
have used to return from hunting, and
one that men today still usually perform
better than women in experiments.
Despite this, the women performed
27 per cent better than men at locating
the food (Proceedings of the Royal Society B, DOI: 10.1098/rspb.2007.0826).
They were also consistently better at
locating high-calorie foods such as olive
oil and honey than low-calorie foods
such as cucumbers, regardless of
whether they liked the stall or the food.
Observations of modern tribes suggest
that foragers need to preferentially
remember where such high-value foods
are, the researchers say.
PITY the villains of the Marvel
comics – they never had a chance
against superheroes like Spider-Man.
An analysis of the social webs within
the fictional Marvel universe reveals
that villains were banished to the
periphery of society, while the
superheroes were well connected.
Physicist Pablo Gleiser of the
National Council for Scientific and
Technical Research in Buenos Aires,
Argentina, studied the social web
within the fictional universe of
Marvel comics, comprising 6486
characters in 12,942 issues. Taking
two characters to be linked if they
appeared in the same issue, he
found a superficially realistic
social network. A small fraction of
characters – notably the superheroes
themselves – had far more links
than most others, acting as key social
hubs. “The Marvel universe looks
almost like a real social network,”
says Gleiser (www.arxiv.org/
abs/0708.2410).
However, even prominent
arch-villains always played marginal
social roles at the periphery of the
network, says Gleiser. He suggests
that this may reflect the restrictions
on comic writers laid down by
the rules of the Comics Magazine
Association of America. One reads:
“Criminals shall not be presented so
as to be rendered glamorous or to
occupy a position which creates the
desire for emulation.”
No wonder the superheroes
always win.
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Only the good have social power
Women are still the best gatherers
www.newscientist.com 1 September 2007 | NewScientist | 21
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