active genes. Microarrays, which can detect the activity of thousands of genes at once, can help predict the toxicity of chemical compounds
SAN FRANCISCO -. Scientists dream of one day using a single chip studded with DNA to help determine the health risks of drugs, food additives and industrial chemicals. Now, this technique has passed a preliminary test with flying colors, the researchers reported here on March 26 at a meeting of the Society of Toxicology.
The principle is simple. The researchers exposed laboratory animals to a chemical, then extract the genetic material called mRNA (which is produced only by active genes) of their cells. A microarray chips or so-called DNA tests for the activity of thousands of genes at once. The profile of active genes should reveal exactly what the toxin is an animal -. If the signal can be distinguished from normal changes in gene activity
therefew months, Cynthia Afshari the National Institute of Environmental Health Sciences in Research Triangle Park, North Carolina, put the new technology to the test. Using microarrays 1,700 genes that may be important in the response of rats to toxins, the team Ashfari first product of genomic fingerprint for two types of liver toxins well studied: phenobarbital and three members of a diversified chemical class of compounds called peroxisome proliferators. Then they did a blind test of rat mRNA from another laboratory.
By comparing gene activity in these 26 extracts the two references, postdoc Hisham Hamadeh of Ashfari correctly identified all the rats that had been exposed to a peroxisome proliferator or phenobarbital derivative. He also acknowledged that several rats were exposed to a wild-card consists not in the database. Hamadeh made only one mistake, misidentification of a wild-card sample as a weak analog of phenobarbital; it was actually an unrelated compound.
The accuracy of DNA matrix surprised scientists who filled the room for the presentation of Afshari. "This work is important," said J. Christopher Corton, the CIIT Centers for Health Research in Research Triangle Park, North Carolina. Toxicologists have a long way to go before they can use genomic tests to predict a wide range of toxicities, he added. But the work of Afshari shows that the objective can be achieved much more quickly than expected, Corton said.
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