Here are some of the latest health and medical news developments, compiled by the editors of HealthDay:

New Rules Would Improve Medical Helicopter Safety

Stricter flight rules being proposed for helicopters in the United Sates include many that would increase the safety of medical helicopters.

The new regulations proposed by the Federal Aviation Administration would require all air ambulance helicopters to have an electronic warning system that alerts pilots about proximity to the ground or other obstacles, the Associated Press reported.

Other proposals for helicopter air ambulances include stricter weather limitations for pilots flying under visual flight rules (without the aid of navigational instruments). In addition, pilots commanding medical helicopters would have to have instrument flight certification.

The proposals represent "significant progress on a very important public health issue," Gary Robb, an author and attorney who specializes in helicopter safety, told the AP.

"About 400,000 people are airlifted every year, and fewer of them will die," if these proposals become law, he said.

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Alfalfa Sprouts Recalled

Possible salmonella contamination has prompted the recall of bulk and retail-size packages of alfalfa sprouts distributed by Michigan-based Living Foods, Inc.

The company said one package of the sprouts tested positive for salmonella and it is working with federal and state officials to determine the source of the salmonella, the Associated Press reported.

The recall includes 4-ounce cups, 4-ounce bags, 5-pound bulk containers, and boxes of four 1-pound plastic bags. All the products have a sell-by date of Oct. 2. Consumers with these products should discard them, Living Foods said.

No illnesses associated with the sprouts have been reported, according to the company, the AP reported.

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Insights Into Molecule May Lead to New Cancer, HIV Treatments

New understanding about the structure of a molecule associated with cancer and HIV infection could lead to the development of new drugs to treat the diseases, say U.S. researchers.

They used a technique called X-ray crystallography to reveal the structure and workings of the CXCR4 molecule, which is part of a family of proteins that control practically every bodily process, BBC News reported.

In normal conditions, CXCR4 helps activate the immune system and stimulate cell movement. But when signals that activate CXCR4 are not properly regulated, the molecule can spur the growth and spread of cancer.

"This is exciting research as CXCR4 has been linked to the growth and spread of a variety of different cancers. Unraveling the structure of this molecule is a vital step towards designing new drugs to help treat cancer," Josephine Querido, senior science information officer at Cancer Research UK, told BBC News.

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Pfizer Recalled Lipitor Because of 'Uncharacteristic Odor'

Drug maker Pfizer Inc. said Thursday that it recalled nearly 200,000 bottles of the anti-cholesterol drug Lipitor in August because of an unusual odor, but there was no risk to consumers, according to published reports.

In a statement to CNN, Pfizer spokesman Rick Chambers said the "uncharacteristic odor" involved bottles from a supplier company. He said a total of seven batches of Lipitor totaling 191,000 bottles were recalled in the United States and Canada, United Press International reported.

The U.S. Food and Drug Administration posted a recall notice Thursday.

"Pfizer has been working closely with the bottle supplier to determine the cause of the odor problem and to rapidly address it," Chambers said. "We don't anticipate a product shortage resulting from the recall."

Pfizer has determined there is no risk of health problems to consumers because of the smell, UPI reported.

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Obama Health Care Law Gets Boost From Michigan Ruling

A constitutional challenge to President Barack Obama's health care reform package suffered a setback Thursday, with a Michigan judge ruling that Congress did not overstep its authority in passing legislation requiring people to purchase health insurance, CBS News reported.

In his ruling, Federal Judge George Caram Steeh rejected claims put forward by the Thomas More Law Center and a number of Michigan residents who said they should not have to purchase a health plan that could fund abortions. The decision hinged on two constitutional issues: whether the legislation contravened the Commerce Clause because it outstripped Congressional authority, and whether it could be considered an unconstitutional tax.

According to CBS, Steeh rejected both arguments, saying that Congress did have the power to pass the law since it had an effect on interstate commerce and was an ingredient in broader regulatory action.

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California Whooping Cough Cases Most Since 1955

California's whooping cough epidemic has reached 5,270 cases, the highest number since the 4,949 cases reported in 1955, the state's health department said this week.

The epidemic of the highly contagious bacterial infection has claimed the lives of nine infants this year. All of them were too young to be fully immunized against the illness, the Associated Press reported.

Typically, babies receive a series of whooping cough vaccinations, followed by booster shots between the ages of 4 and 6 and again after they're 10 years old. Booster shots are recommended every 10 years for adults.

Last week, Gov. Arnold Schwarzenegger signed a bill that will require all junior and high school students in the state to get booster shots against whooping cough before the start of school in 2011. That requirement will be extended to students entering grade 7 in the fall of 2012, the AP reported.

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U.S. Lags in Life Expectancy Gains: Study

The United States is falling behind other nations when it comes to gains in life expectancy, finds a new study.

For example, even though life expectancy in the U.S. rose between 1975 and 2005, the life expectancy ranking for a 45-year-old man in the U.S. fell from third place to 12th during that time, while 45-year-old American women were in last place, United Press International reported.

The researchers at Columbia University's Mailman School of Public Health in New York analyzed data from the U.S., Australia, Belgium, Canada, France, Germany, Italy, Japan, the Netherlands, Sweden, Switzerland and the United Kingdom.

The study, which appears in the journal Health Affairs, was conducted for the Commonwealth Fund.

The researchers said the U.S. decline in life expectancy ranking may be due to reasons such as unregulated fee-for-service health care payments and a reliance on specialty care, UPI reported.