...And optimism about a novel therapy....and optimism about a novel therapy A custom-designed, boron-containing compound that tumor cells absorb and retain preferentially has potential as a cancer therapy, scientists report. When the compound is irradiated with a beam of "slow neutrons" -- a form of low-energy radiation that does not by itself cause tissue damage -- the boron boron (bōr`ŏn) [New Gr. from borax], chemical element; symbol B; at. no. 5; at. wt. 10.81; m.p. about 2,300°C;; sublimation point about 2,550°C;; sp. gr. 2.3 at 25°C;; valence +3. atoms split and "explode" like tiny atomic bombs, killing the cancer cell. Researchers say experiments on cultured hamster hamster, Old World rodent, related to the voles, lemmings, and New World mice. There are many hamster species, classified in several genera. All are solitary, burrowing, nocturnal animals, with chunky bodies, short tails, soft, thick fur, and large external cheek cells and in mice with cancer indicate the treatment is one of the more promising new applications of "neutron capture Neutron capture is a kind of nuclear reaction in which an atomic nucleus collides with one or more neutrons and they merge to form a heavier nucleus. Since neutrons have no electric charge, they can enter a nucleus more easily than charged particles which are repelled by therapy." Scientists have experimented with similar treatments since the 1950s, but with poor results. Stephen B. Kahl and his colleagues at the University of California, San Francisco , deeloped the molecular "package bomb" as a 20-sided solid with one atom of boron-10 -- a neutron-absorbing isotope of boron--at each of the molecule's 12 corners. Four or more of these icosahedrons are bound together to a molecule of porphyrin, an iron-containing molecule that remains preferentially incancer cells. The advantages of this approach are many, Ralph Fairchild of the Brookhaven National Laboratory Brookhaven National Laboratory, scientific research center, at Upton (town of Brookhaven), Long Island, N.Y. It was founded in 1947 by Associated Universities, a management corporation sponsored by nine eastern U.S. universities. in Upton, N.Y., told SCIENCE NEWS. Since neutron beams can penetrate far into the body, even deep-seated tumors can be targeted, he says. And because the boronated compound actually enters the tumor cells-rather than simply binding to the outside membranes as is the case with similar experimental therapies--the approach is effective withonly one-tenth the amount of boron that would otherwise be required. Boron is normally nontoxic but becomes radioactive when exposed to slow neutrons. Fairchild notes that Kahn's boron compound is the most efective of a half-dozen target compounds his team has looked at so far. Within one to two years, the San Francisco researchers say, clinical tests may begin on patients with a deadly form of brain tumor Brain Tumor Definition A brain tumor is an abnormal growth of tissue in the brain. Unlike other tumors, brain tumors spread by local extension and rarely metastasize (spread) outside the brain. called glioma glioma /gli·o·ma/ (gli-o´mah) a tumor composed of neuroglia in any of its states of development; sometimes extended to include all intrinsic neoplasms of the brain and spinal cord, as astrocytomas, ependymomas, etc. . Preliminary experimental results were presented recently at the American Chemical Society's national meeting in Los Angeles. |
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