First bioengineered animal drug approved After nearly a decade of effort—and years of political and scientific contro­versy—Monsanto won Food & Drug Administration approval Nov. 5 to mar­ket genetically engineered bovine soma­totropin (BST), a protein hormone that increases milk production in cows.

Monsanto says it is pleased that it will be the first to bring this type of product to market, and that it can now begin to recoup its "significant investment."

But that won't happen immediately. In August, Congress imposed a 90-day moratorium on BST sale to take effect after FDA approval (C&EN, Aug. 16, page 4). Monsanto will use the interval to educate farmers and veterinarians on the benefits of BST use. Up to now, the company has been limited to talk­ing about human safety.

Monsanto believes BST promises con­siderable benefits. In test herds, cows re­ceiving a small subcutaneous injection of BST every two weeks produced an aver­age 9 lb more milk per day than untreat­ed cows. Milk from these test herds has been sold since 1985. Prosilac, Monsan-to's trademarked name for its BST, in­creases milk output by supplementing natural BST produced in a cow's pitu­itary gland. BST allows farmers to pro­duce more milk with fewer cows.

A September 1992 General Account­ing Office study reported that FDA found evidence in trials that BST-treated

Feingold: consumers don't want BST

cows have 15% more cases of mastitis, a common udder infection, raising con­cern that increased use of antibiotics to treat the disease might lead to increased residues of such drugs in milk. Howev­er, after review, FDA concluded that ad­equate safeguards are in place to prevent sale of milk with unsafe residue levels.

"There is virtually no difference in milk from [BST-]treated and untreated cows," says FDA commissioner David A. Kessler. "In fact, if s not possible us­ing current scientific techniques to tell them apart. This has been one of the most extensively studied animal drug products to be reviewed by the agency . . . we are confident that this product is safe for the consumers, for cows, and for the environment."

Still, opposition to BST's use remains strong. Some opponents—such as Sen. Russ Feingold (D.-Wis.), who spear­headed the moratorium effort in Con­gress—argue that the U.S. simply doesn't need cows that can produce more milk. He calls FDA's action "another threat to small family farms."

Feingold points out that during the 90-day moratorium, the federal govern­ment is mandated to conduct a study of the budgetary, social, and economic ef­fects of widespread use of this new tech­nology, and to report its findings to Con­gress within 45 days. "I hope that the Administration's study will accurately reflect what I've been hearing from farmers all over Wisconsin," Feingold says: "that BST is bad for the dairy in­dustry, that we don't need it, and that consumers don't want it in their milk."

Other opponents—such as Consum­ers Union and the Foundation on Eco­nomic Trends' Pure Food Coalition— charge that BST is unsafe for cows and threatens human health. They say that FDA is failing to protect consumers from dangerous drug residues in milk.

The coalition, created by long-time biotechnology critic Jeremy Rifkin, is organizing numerous demonstrations against BST, beginning last week in Boston, Chicago, Cincinnati, Madison (Wis.), and Milwaukee. It also will con­duct a national advertising campaign urging consumers to purchase only dairy products clearly labeled as being BST free. On Feb. 3,1994, the day Mon­santo can begin selling BST, John C. Stauber, national organizer for the coa­lition, promises milk dumping demon­strations in more than 800 cities.

Janice Long

Scanning microscopy enters picosecond realm Two research groups, working inde­pendently, have combined scanning tunneling microscopy with ultrafast la­ser optics to create a powerful new tool for probing surface phenomena not only on the atomic length scale of angstroms (10~10 meter), but also on the atomic time scale of picoseconds (10~12 second).

One of the researchers, Daniel S. Chemla, a physics professor at the Uni­versity of California, Berkeley, says the technique opens "a new window on time and space": It potentially could be used to make "movies" of physical and chemical processes that occur at speeds of a few angstroms per femtosecond (10~15 second).

The two groups were unaware of each other's efforts until recently. One team, led by Chemla, who directs Lawrence Berkeley Laboratory's mate­rials science division, published its findings in the Nov. 1 issue of Applied Physics Letters [63, 2567 (1993)]. The other team, led by physicist Mark R. Freeman of IBM's Thomas J. Watson Research Center in Yorktown Heights, N.Y., described its results last week in Science [262,1029 (1993)].

Both groups used a different nonlin-earity to resolve, on picosecond time scales, signals that result from laser ex­citation. Freeman's group used the nonlinear relationship between the cur­rent and voltage of a scanning tunnel­ing microscope (STM). Chemla's group used the nonlinear response of a light-activated switch on the STM tip. The underlying principle is general and could be applied to the many other types of scanning probe microscopes.

Chemla's group can image surfaces with two-picosecond time resolution and better than 50-À spatial resolution. Conventional STMs offer better spatial resolution. But a compromise was nec­essary, Chemla notes, to achieve a time resolution that he says is nine orders of magnitude better than that currently attainable with the STM. Two indepen­dent scientists consulted by C&EN con­sidered Chemla's nine orders of magni­tude claim somewhat overstated, but they had not yet seen his paper.

Freeman and his former coworker, Geoff Nunes Jr., explain that the new STM method serves as a stroboscope

NOVEMBER 15,1993 C&EN 9