California

DNA evidence defended in Laci Peterson case

An FBI scientist Wednesday denied that a DNA sample used to link Laci Peterson to a hair on her husband’s boat was contaminated.

Bruce Budowle was called by prosecutors to rebut testimony from a defense expert who had criticized the DNA techniques used to analyze the hair, found in pliers in the boat Scott Peterson said he took fishing the day Laci disappeared.

Budowle said the database the FBI used to determine the probability that the hair could have been from the 27-year-old Modesto woman was large enough that scientists were confident of their findings.

The hair has become the most time-consuming element in the preliminary hearing to determine if there is enough evidence to try Peterson on charges of murdering his wife and unborn son. Their bodies were washed ashore in April in the Bay Area.

San Francisco

Experimental vaccine fails in AIDS study

An experimental AIDS vaccine tested in Thailand on some 2,500 drug users failed to protect them from becoming infected with HIV, the vaccine’s developer said Wednesday.

The poor results were widely expected since VaxGen Inc. had said earlier that its vaccine did not work in a larger North American study.

Two dozen other vaccines are being tested on 12,000 human volunteers.

Officials at Brisbane, Calif.-based VaxGen said the Thai results underscored again how wily AIDS was in thwarting the immune system.

VaxGen’s vaccine, like most others being tested, did not contain the virus itself and cannot cause AIDS. Instead, the vaccine contained small, manmade genetic bits of the virus that scientists had hoped would provoke an immune response strong enough to stop the virus from invading healthy cells.