Here are some of the latest health and medical news developments, compiled by editors of HealthDay:
Texas Scientists Test Ricin Vaccine
Researchers at the University of Texas Southwestern Medical Center will start conducting human clinical trails to test the safety of an experimental vaccine against ricin, the deadly toxin.
The researchers received approval from the U.S. Food and Drug Administration to test the genetically engineered protein vaccine RiVax, the Associated Press reported.
The vaccine was developed by a team led by Dr. Ellen Vitetta of UT Southwestern.
In this trial, volunteers will be given the vaccine and their blood will then be checked to see if their bodies produce protective antibodies. Those antibodies would then be injected into mice that would be exposed to lethal doses of ricin in order to assess the protective effects of the human antibodies, the AP reported.
As little as 500 micrograms of ricin -- an amount that would fit on the head of a pin -- can kill an adult. There are concerns that ricin could be used in a bioterror attack.
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Experts Blast U.S. Abstinence Emphasis
On the eve of World AIDS Day, the United States is being condemned for its emphasis on sexual abstinence among young people as a way of slowing the spread of HIV/AIDS.
Several experts have repeated their criticism of the U.S.-backed ABC campaign, which is a pillar of the Bush administration's $15-billion, five-year commitment on AIDS. At the request of U.S. religious groups, 7 percent of that money is to be spent on promoting abstinence, Agence France-Presse reported.
In the ABC campaign, "A" is for abstinence, "B" is for being faithful to a single partner if abstinence doesn't work, and "C" is for condom use if the first two approaches fail.
Critics charge that the ABC campaign is often ineffectual and wasteful and even a potential threat to lives. It's unworkable in African countries where HIV and sexual activity are rampant, said Mary Crewe, director of the Centre for the Study of AIDS at the University of Pretoria in South Africa.
"In countries where there are very high levels of sexual activity around, with social dislocation, family breakdowns, sugar daddies, with young people bored and with nothing to do, to suddenly come in and say you should stop having sex is absolutely ludicrous," Crewe told the AFP.
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Japanese Cows Get ID Codes
In an attempt to ease fears about mad cow disease, Japan will give all cows in the country an identification code that can be checked by consumers before they dig into their steaks or other beef products.
Consumers will be able to enter the codes into their cell phones or computers in order to trace the history of individual cows, from birth to slaughter and into supermarket coolers and freezers.
This information about the source of their beef will allow people to avoid meat from farms with a history of previous mad cow disease, Agence France-Presse reported.
The ID system will be implemented Wednesday and will apply to both Japanese-bred and imported beef cattle. Japan is the only Asian country that's had confirmed mad cow disease.
It's unknown how people eating in restaurants would track the history of the cow, according to AFP.
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Stress Speeds Up Aging, Researchers Confirm
Long-term stress can make people sick and grow old before their time, according to a new study that has identified the first direct link between stress and aging, the Washington Post reported Tuesday.
Constant stress seems to speed up the shriveling of genes inside cells that naturally occurs during the aging process, according to scientists at the University of California at San Francisco (UCSF). If the small study's results are confirmed in larger trials, it would represent the first confirmation at the cellular level that chronic stress accelerates the aging process, the newspaper reported.
Lead researcher Elissa Epel, a UCSF psychiatrist, and her colleagues studied 39 women ages 20 to 50 who suffered chronic stress because they had been caring for a chronically ill child. The researchers studied telomeres, which are caps at the ends of chromosomes that naturally get shorter and shrivel as cells age and continue to divide. The scientists concluded that chronic stress appears to speed up this process.
A key factor appeared to be women's perceptions of how stressed they were. Those who professed to be under the most stress had telomeres equivalent to someone 10 years older, the researchers said.
The study appears in the Nov. 29-Dec. 3 issue of the Proceedings of the National Academy of Sciences.
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New Cancer Drug Extends Survival
The new Genentech, Inc., cancer drug Avastin appears to extend survival for patients with colorectal cancer by nearly two months, U.S. National Cancer Institute researchers have concluded.
Avastin is the first among a new class of drugs designed to kill tumors by cutting off their blood supply, according to an account in the San Jose Mercury News. The drug was approved by the U.S. Food and Drug Administration in February.
Avastin was studied among a group of 829 patients who had already failed earlier treatment. Patients who received the drug plus standard chemotherapy had a median survival of 12.5 months, compared with 10.7 months among those who took chemotherapy alone.
Avastin does increase a user's risk of heart attack and stroke, particularly among older patients who have a history of cardiovascular problems, the newspaper reported. Deaths due to those complications were included in the survival statistics.
A month's supply of Avastin sells for about $4,400, the Mercury News reported.
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Fossil Fuel Exhaust Shortens Life
Fine-particle pollution caused by the burning of fossil fuels and wood is cutting life expectancy in Europe by as much as two years, a new United Nations-sponsored report found.
Other recent studies have concluded that particles narrower than a human hair can invade the lungs and bloodstream, causing respiratory and cardiovascular problems, according to an account by the Associated Press.
While larger particles tend to fall from the air quickly, finer pollutants can travel long distances from their sources, which may include motor vehicles, power stations, and factories. The Vienna-based International Institute for Applied Systems Analysis, which is conducting the research, said the problem of fine-particle pollution is most serious in the nations of Belgium, the Netherlands, northern Italy, and parts of the former Soviet Union, the AP reported.
While the study included only European nations, Asia, the United States, and other parts of North America are similarly afflicted, an institute spokesman told the AP.
