News From The American Chemical Society

Main Category: Biology / Biochemistry
Also Included In: Nutrition / Diet;  GastroIntestinal / Gastroenterology
Article Date: 08 Jan 2008 - 6:00 PDT

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Benzene concentrations in beverages

Only nine percent of 199 beverage samples had benzene levels above the U. S. Environmental Protection Agency (EPA) limit of 5 parts per billion (ppb) for benzene in drinking water, according to a study by EPA and U. S. Food and Drug Administration (FDA) scientists. It is scheduled for the current issue of ACS' Journal of Agricultural and Food Chemistry, a bi-weekly journal.

Products containing benzene above the EPA level were reformulated by the manufacturers to minimize or eliminate benzene and one product was discontinued, researchers said. Benzene levels in the reformulated products were 1.1 ppb or less. About 71 percent of beverage samples in the study contained less than 1 ppb. Based on results from the survey and actions taken by the beverage industry, FDA concluded that the levels of benzene found did not pose a safety concern for consumers.

In the study, FDA's Patricia Nyman and colleagues point out that benzene can form at ppb levels in some beverages that contain a food preservative, benzoate salt, and ascorbic acid (vitamin C). In the early 1990s, the U.S. beverage industry discovered benzene in some beverages and reformulated those products. In 2005, the substance again was found in some beverages, likely because new manufacturers were unaware of the problem, the study says. Some manufacturers also have added vitamin C to drinks in response to consumers' desire for healthier products.

The study found that product formulation, shelf-life, and storage conditions were important factors affecting benzene formation. The report also describes the in-house validation of FDA's analytical method for determining benzene in beverages. - JS

ARTICLE: "Survey Results of Benzene in Soft Drinks and Other Beverages by Headspace Gas Chromatography/Mass Spectrometry"

CONTACT:
Patricia Nyman
U.S. Food and Drug Administration
College Park, Md. 20740

Toward solving the mystery of idiosyncratic drug reactions

A mysterious and unpredictable group of side effects from modern medications called idiosyncratic drug reactions (IDRs) likely will persist as a major health care problem unless there is a dramatic increase in research funding, according to a 20-year review of research in the field scheduled for the January issue of ACS' Chemical Research in Toxicology, a monthly journal.

The review, by Jack Uetrecht, defines IDRs as reactions that happen unexpectedly and with no obvious connection to the known effects of a medication's ingredients or dosage. Although relatively rare, IDRs make an important contribution to the annual burden of death, illness, and increased health care costs from serious adverse drug reactions. In addition, serious IDRs that appear after a new drug has gone into wide use can force drug companies to withdraw products after R&D investments totaling hundreds of millions of dollars.

Two decades of research have produced significant progress, the report acknowledges. However, medical science still has only a "superficial" understanding of how and why IDRs occur and a growing recognition that the mechanisms behind IDRs may be as complicated as those involved in cancer or diabetes. The review describes a need for increased research funding, with more scientists focusing on IDRs, in order to achieve faster progress. - JS

ARTICLE: "Idiosyncratic Drug Reactions: Past, Present, and Future"

CONTACT:
Jack Uetrecht, M. D., Ph.D.
University of Toronto
Toronto, Canada M5S, 3M2

Discovery of enzyme's structure may lead to new treatments for celiac disease

Researchers have discovered a new structure for a key enzyme associated with celiac disease, a finding that could lead to the design of new medications for the common digestive disorder, according to an article in Chemical & Engineering News, ACS' weekly newsmagazine.

Celiac disease is a condition in which the stomach cannot properly digest wheat and other gluten-containing foods. The disease afflicts an estimated 2 million people in the United States alone.

In the article, C&EN Deputy Assistant Managing Editor Stu Borman notes that the disease is believed to occur when the protein gluten interacts with an enzyme called transglutaminase 2 (TG2), triggering an autoimmune reaction that damages the small intestine and causes diarrhea, abdominal pain and other symptoms. As a result, people with the disease are urged to follow a strict gluten-free diet.

Although scientists have previously obtained the X-ray crystal structure of human TG2, they have only revealed its "closed" or inactive form, the article points out. Now, Chaitan Khosla and colleagues at Stanford University report the first-ever determination of the "open" structure of the enzyme, in which its active site is accessible to substrates. The finding that could help scientists design inhibitors of the enzyme that could serve as medications for celiac disease and other related conditions, according to the article.

ARTICLE: "Enzyme opens for business"

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Article adapted by Medical News Today from original press release.
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The American Chemical Society - the world's largest scientific society - is a nonprofit organization chartered by the U.S. Congress and a global leader in providing access to chemistry-related research through its multiple databases, peer-reviewed journals and scientific conferences. Its main offices are in Washington, D.C., and Columbus, Ohio.

Source: Michael Woods
American Chemical Society