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Betreff:
Electronics Zero
in on Cancer Cells |
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Von: Iris Atzmon |
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Datum: Wed, 5 Sep 2007 20:31:45 +0300 |
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From a cancer forum
----- Original Message -----
From: Sally Gould Good afternoon, Cited
below is a fascinating article on using electronics to zero in on cancer
cells. Researchers
are using a: "....minimally invasive surgical technique that
makes use of irreversible electroporation, essentially killing cancer cells with short
electrical pulses while leaving neighboring healthy cells unharmed"
.... And this procedure has been shown to cure cancer in lab rats. Different
types of cancerous tissues have been treated in lab animals. What is
interesting is that, apparently, with the short electrical pulses, there is no
harmful heat produced. And
what is really cool is that the researchers have slated human trials for
prostate cancer for next year. Sally
News & Trends To print: Select File and
then Print from your browser's menu. Electronics zero in on cancer cells Curing cancer is usually
the domain of medical doctors, but biomedical engineers at Virginia Tech and the
University of California at Berkeley have now invented a promising electronic
therapy. Using short electrical
pulses that target only cancer cells, together with
real-time monitoring via electrical impedance tomography, the procedure has
already been shown to cure cancer in lab rats. "We have invented an
inexpensive, minimally invasive surgical
technique that makes use of irreversible electroporation, essentially
killing cancer cells with short electrical pulses while leaving neighboring
healthy cells unharmed," said bioengineering professor Rafael Davalos of Virginia Tech's
School of Biomedical Engineering and Science. "We are also using
electrical-impedance tomography to monitor progress and make sure all the
cancer cells get treated." Work has progressed from
cell cultures to rats to mice, with human
trials on prostate cancer slated for next year. If those trials are
successful, curing other types of cancer will be tried in humans. Opening pores Davalos
and UC-Berkeley collaborator Boris Rubinsky, however, use extended sessions
with the electrical pulses to electrocute the cancer cells, permanently
opening pores that kill the cell as its contents drain out. "We use needle electrodes to surround the cancerous
area, then we use external electrodes to monitor our progress with
electrical-impedance tomography," said Davalos. "When the pores
stick open on a cell, it lowers the bulk resistance of that tissue, which we
can image with submillimeter cell-scale resolution." By
treating an area while watching their progress using tomography, then moving
the needles and repeating as necessary, the engineers have been able to treat
different types of cancerous tissue in laboratory animals. The treatment
takes about 1min. per affected area. "The pulses are so short that the
cells don't heat up," added Davalos. Freezing cancer "Our procedure doesn't affect neighboring
cells," said Davalos. "Our treatment is also
tissue-independent—all cells just behave in this way. All we have to be
able to do is get the needles to the targeted area, and in just one treatment
you are rid of the cancer." A key problem with traditional
cancer treatments, the researchers said, is that oncologists cannot tell if
the cancer cells are dead until a week or so after treatment. Consequently,
if oncologists are not aggressive enough during the treatment, they can miss
some cancer cells, and if they are too aggressive, they can damage
surrounding healthy tissue. "With other
procedures, you don't get immediate feedback. With ours, you can see how
successful the treatment is as you go along," said Davalos. - R. Colin Johnson
Posted: 03
Sep 2007
Engineers have been using electroporation since the mid-1960s to take
electronic control of the pores in a living cell's outer membrane. For
instance, genetic engineers routinely use electroporation to load DNA
sequences into cells. By using 2,500V
electrical pulses that are 100µs long, pores can be opened in any cell
membrane, allowing liquids to flow in and out. Other cancer
researchers use electroporation to temporarily make tumor cells more
permeable to cancer-killing drugs than to the surrounding healthy tissue.
Another technique can claim the same thing: Cryoablation freezes cancer
cells. The downside is that killing the cancer cells with cold sometimes
damages nearby healthy cells, just as heat can.
EE Times