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CONCENTRATES HEQNiiEia
Nanotubes cross cell membranes
alkaline conditions. However, the pentoses under those conA carbon-nanotube-based carrier system that could have ditions rapidly decompose to applications in drug and vaccine delivery has been discovered by sci- polymeric mixtures of brown entists in Europe. Organic chemistry professor Maurizio Prato at tar. A team led by University of the University oflrieste, in Italy, Alberto Bianco, an organic chemist Florida chemistry professor at the Institute ofMolecular & Cellular Biology, Strasbourg, France; StevenA. Benner shows that boand their colleagues show that single-walled carbon nanotubes rate minerals help stabilize ri(SWNTs) functionalized with a fluorescent probe—fluorescein bose synthesized under alkaline isothiocyanate (FITC)—or with an FITC-peptide conjugate are conditions [Science, 303,196 able to penetrate the membranes of human and mouse fibroblasts (2004)}. In the absence of bo[Chem. Comm., 2004,16}. Functionalized SWNTs could be used rate, a mixture of pentoses, into deliver peptides or small organic molecules into cells, the authors cluding ribose, turns brown and suggest. Both types of SWNTs are water soluble and nontoxic to degrades after an hour of incuthe cells at low concentrations. The SWNT-FITC derivative bation. When the mixture is in(shown) accumulates mainly in the cytoplasm of the cells, whereas cubated in the presence of borate minerals, the solution the S WNT-peptide-FITC derivative enters the nudoesn't degrade over an extendclei. How the nanotubes get across the memed period. Borate minerals were branes remains to be elucidated. 'The abprobably also available on early sence of immunogenicity of the Earth. The authors argue that nanotubes, in comparison to their results help support—or common protein carriers, will at least don't exclude—prebiotincrease the efficacy of the ic formation of ribose. therapeutics delivered in this manner," the group notes.
ering penetration enhancers, in which the penetration of radiolabeled solutes into or across the skin is measured. Using the INSIGHT method with a library of more than 5,000 formulations, they found potent penetration enhancers that cause minimal skin irritation. Two promising formulations increased the flux of macromolecular drugs across skin during in vitro experiments. And one formulation was used to deliver leuprolide acetate across the skin of hairless rats in vivo.
Contaminants in farmed salmon
Farm-raised salmon hold more persistent chlorinated contaminants, including polychlorinated biphenyls and transport 'pollution' nitrogen dioxins, than those caught in to pristine or rural sites," Sparks the wild, according to a resays. When plants take up search collaboration led by enPAN, the pollution is distribResearchers have gathered uted less widely. Sparks and Despite the advantages of vironmental chemistry profesthe first proof that plants take coworkers estimate that plants transdermal drug delivery such sor Ronald A. Hites at Indiana up a reactive organic nitrogen remove about 3% of the total as increased patient compli- University [Science, 303, 226 gas from the atmosphere [Geo- reactive nitrogen in air. This af- ance, only a few drugs are de- (2004)}. In addition, farmed phys.Res.Lett., 30,2189 (2003)1. fects not only global nitrogen livered via patches, and those salmon bought in European By directly measuring the en- cycling, Sparks says, but carbon are generally small molecules. cities hold more contaminants try of peroxyacetyl nitrate cycling as well; plants with more Chemical engineers at the Uni- than equivalent fillets picked (PAN) through the leaf pores, nitrogen available to them can versity of California, Santa Bar- up in North American cities. or stomata, of eight plant do more photosynthesis and bara, have developed a method (Much of the farmed salmon that could make it easier to find sold in the U.S. comes from species ranging from mango to take up more C0 2 . effective transdermal formula- Canada and Chile; salmon sold lodgepole pine, Jed P. Sparks, a tions. In a method that they in Europe are usually raised professor of ecology and evolucall INSIGHT screening (for in European waters.) The retionary biology at Cornell Uniin vitro skin-impedance-guid- searchers suspect that farmversity andhis colleagues at the ed high-throughput screening), raised salmon accumulate more University of Colorado, Boulder, and the National Oceanic For the "RNA world" hypoth- assistant professor Samir Mi- contaminants because ofwhat &AtmosphericAdministration esis of the origins of life to be tragotri, grad student Pankaj they eat. Feed used on salmon watched plants breathe in re- true, RNAmust have been syn- Karande, and postdoc Amit farms consists offish oil and active nitrogen. Sparks calls thesized prebiotically Ribose— Jain use impedance mea- meal made from small oceanic PAN a transport compound for the sugar in RNA—and other surements of skin to identify fish. The oil concentrates the reactive nitrogen. The two pentoses can be made from combinations of penetration contaminants. And perhaps main nitrogen gases emitted by the precursors formaldehyde enhancers that improve trans- European feed holds a higher cars and factories, NO and and glycolaldehyde, which are dermal delivery [Nat. Biotech- load of contaminants, the reN 0 2 , don't travel far alone. In- known to exist in interstellar nol., published online Jan. 4, searchers say, because it comes from the more industrial wastead, they are incorporated in- space and presumably would http://dx.doi.org/10.1038/nbt9 to larger organic molecules— have been available on early 28}. Their screening method is ters of Europe's North Atlantic most commonly PAN. "In Earth. Using these precursors, 100 times more efficient than compared with the waters off effect, PAN is the form that can pentoses can be formed under the current method of discov- North and South America.
Helping drugs go more than just skin deep
Plants pick up gaseous nitrate
Borates stabilize ribose
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C&EN / JANUARY
12, 2004
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