But daily use of the antiretroviral drug commonly known as Truvada may greatly cut the chance of getting infected with AIDS, researchers have found in a groundbreaking new study.
The study published November 2010 in the New England Journal of Medicine offered the first indication of an oral method to prevent the spread of HIV among those at high risk.
"This is an important trial that further extends the growing appreciation that antiretroviral therapy can play a vital role in controlling the HIV epidemic," said Dr. Paul Volberding, co-director of the University of California San Francisco Center for AIDS Research, who was not involved with the study.
Although the study was limited to one kind of high-risk group, further pre-exposure prophylaxis (PrEP) studies are looking at other groups at risk for transmission, including heterosexual couples and intravenous drug users. Researchers also plan to conduct a longer term follow up to the original published study beginning 2011.
For years, scientists have been able to genetically modify plants and animals. But this year, for the first time, a group of researchers successfully created the first man-made cell.
Researchers at the private firm J. Craig Venter Institute replaced the genome of a bacterium with one they wrote themselves. The cell turned into a different species than its original form and was able to live and replicate.
"[The new cell is] the first self-replicating species we've had on the planet whose parent is a computer," Dr. Craig Venter said at a news conference in May announcing the technique's success.
The so-called synthetic cell further pushed open the door to synthetic biology, combining chemicals, biology and genetics research to replicate fuels, vaccines and living organisms.
Bisphosphonates are commonly prescribed to prevent osteoporosis and make bones stronger. But an ABC News investigation found mounting evidence that for some women, taking the popular osteoporosis drug Fosamax or its generic alendronate for more than five years could cause spontaneous thigh-bone fractures.
The U.S. Food and Drug Administration announced in March that it will look into whether a link exists between the long-term use of the osteoporosis drugs and femur fractures after ABC News investigated the possible connection.
"We are seeing people just walking, walking down the steps, patients who are doing low-energy exercise," said Dr. Kenneth Egol, professor of orthopedic surgery at NYU Langone Medical Center. "Very unusual, the femur is one of the strongest bones in the body."
Egol said X-rays of some of his patients look more like an injury endured by a car accident than an otherwise minimal fall.
Many studies suggest an overall benefit from taking the medication for women who are at risk for osteoperosis. Indeed, bisphosphonates can help prevent hip and spine fractures, which for many women may lead to death.
Although bisphosphonates are generally recommended for postmenopausal women, research does not indicate how long women should be on the drug. Many doctors now recommend a five-year limit.