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This Week
Eight MS flare-ups, or relapses, occurred
among the patients during the study, but
seven of these struck patients who had finished receiving the vaccine, says study coauthor Amit Bar-Or, a neurologist and immunologist at McGill University in Montreal.
These results allayed concerns that the vaccine might exacerbate MS.
Spinal fluid obtained from three patients
before and after getting the vaccine showed
a reduction in rogue antibodies that react
against myelin. In addition, blood samples
from five patients showed a decrease in
immune T cells that react to myelin.
“This is an important development in the
field of MS therapy,” says immunologist
Gérald J. Prud’homme of the University of
Toronto, who wasn’t part of the study team.
“This is the first demonstration of a beneficial effect of DNA vaccination in a clinical trial of autoimmune disease.”
The vaccine may inhibit myelin damage
in several ways, Bar-Or says. For example,
the vaccine’s DNA apparently enters the
nuclei of dendritic cells and other traffic
cops that orchestrate immune reactions,
he says. Because of the DNA’s tweaked
structure, the myelin basic protein that
these cells then produce isn’t seen as an
enemy, and other immune cells decrease
their responses against it.
This calming effect may extend to
immune cells targeting central nervous system proteins besides myelin basic protein.
However, more work needs to be done to
confirm this, Bar-Or says.
Meanwhile, the findings have cleared
the way for a larger trial designed to assess
whether the therapeutic vaccine can limit
the nerve damage that marks MS. In that
study, researchers have already given
290 patients a longer course of the vaccine
than the safety study entailed. The team
expects to release the results of the current study within the next year. —N. SEPPA
“We can image the cell as it is,” says Won- That 360-degree scan can yield a more
shik Choi of the Massachusetts Institute of detailed 3-D image than the MI T device
Technology (MIT). The new device could be provides, Depeursinge says. However, the
retrofitted to existing microscopes and Swiss team’s technique required sus-could track dynamic processes such pending cells in glycerin.
as cell reproduction or microbial “The main advantage of [the
invasions, Choi adds. MIT] approach seems to be
Most cells are colorless, speed,” says Stanford
translucent, and barely University’s Thomas
visible even under Baer. That could
a microscope. For enable researchers
more than a cen- to image viruses,
tury, researchers bacteria, or other
have stained living microbes as they
cells with dyes to invade cells, and
increase the con- “lead to a better
trast between parts understanding of
such as the nucleus how these processes
and the cytoplasm. occur,” Baer says.
In recent years, re- The MIT researchers
searchers have learned say that their device can
to image live cells by take as many as 10 frames
mapping how the cells’ per second, making it pos-materials slow the speed sible to film such
of light to different INTIMATE VIEW Nucleoli in this processes as they
extents. Light’s lower cervical cancer cell appear green, unfold—although real-speed in water than in indicating slower light propagation than time imaging is not yet
air is what makes a pen- in the cytoplasm, which appears red. possible, since com-cil look broken when it’s puters take up to 30
dipped halfway into water. minutes to process each frame. “One obvi-
In the MIT device, a laser beam passes ous thing” would be to make a movie of a
through a sample into a microscope and cell as it divides, says MIT team leader
then on to a digital camera. The camera’s Michael Feld. —D. CASTELVECCHI
detector records tiny shifts in the light
waves with respect to a reference beam
from the same laser. Those shifts indicate
how the laser light slowed as it crossed different cell parts.
A system of tilting mirrors and lenses
deflects the beam, allowing it to scan the
sample across a 120-degree range of viewpoints. A computer algorithm—similar to
the ones that produce computerized tomography scans from multiple X-ray views—
then reconstructs a 3-D image of the sample. Differences in the speed of light as it
passes through various parts of the cell can
be displayed as different colors.
The researchers produced distinct
images of nucleoli—structures contained
in cellular nuclei—and the cytoplasm of cervical cancer cells, they report in an upcoming Nature Methods. The team also scanned
and highlighted the internal structures of
live microscopic roundworms.
The researchers estimate that their
equipment can already resolve details as
small as half a micron, and that they can
probably bring the resolution down by
two-thirds. Other imaging devices, such
as electron microscopes, have much
higher resolution, but they can’t image
living cells.
Last year, Christian Depeursinge and his
colleagues at the École Polytechnique
Fédérale in Lausanne, Switzerland, took
similar 3-D scans of cells by rotating the
sample while holding it inside a pipette.
Shocking
Sheets
Power paper packs
a punch
A Moment in
the Life of a Cell
Microscopic scan images
without intruding
A new imaging tool could enable re-
searchers to get three-dimensional images
of single living cells without resorting to the
time-honored procedure of staining their
inner structures with chemicals.
A new, ultrathin material made from cellu-
lose, the main ingredient in paper, could
power future electronic gadgets, medical
implants, and even hybrid vehicles. Developed by researchers at Rensselaer Polytechnic Institute in Troy, N. Y., the material can
be rolled into a tube, folded, and cut into different shapes with no effect on its function.
“This new, paperlike energy device could
fundamentally change the way we power
things,” says Ning Pan, a materials scientist at the University of California, Davis.
Rensselaer biomaterials specialist Robert
Linhardt and his students conceived the
power paper while experimenting with cellulose membranes for kidney-dialysis
machines. To strengthen the membranes,
the researchers thought of mixing the cellulose with carbon nanotubes.
Working with Pulickel Ajayan, a carbon-nanotube researcher at Rensselaer, the Linhardt team dissolved cellulose in an ionic
liquid—a liquid salt—and poured the solution over an array of vertically aligned carbon nanotubes on a silicon wafer. The
CHOI
