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

FDA Approves Breathing Aid Used By Christopher Reeve

A device that helps people with spinal cord injuries breathe without a ventilator for at least four hours at a time has been approved by the U.S. Food and Drug Administration, the agency said Wednesday.

Actor Christopher Reeve, who died in 2004, first used the then-experimental device a number of years ago, the Associated Press reported. He had been paralyzed below the neck after a horseback riding accident in 1995.

The NeuRX DPS RA/4 Respiratory Stimulation System uses four electrodes to stimulate the diaphragm, a lower abdominal muscle that's essential for breathing. People who are paralyzed due to spinal cord injury often lose control of the muscle, which contracts when a person inhales and relaxes when a person exhales.

"While the NeuRx RA/4 does not cure paralysis of the diaphragm, allowing patients to be free from a mechanical ventilator for at least four hours a day may enhance their quality of life," Dr. Daniel Schultz, director of the FDA's Center for Devices and Radiological Health, said in a statement.

The device is manufactured by Synapse Biomedical Inc., in Oberlin, Ohio.

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Tiger Woods Facing Knee Surgery, Out for Season

Golf legend Tiger Woods will miss the remainder of the 2008 season to have reconstructive surgery on a torn anterior cruciate ligament (ACL) in his left knee.

Woods tore the ligament last summer while running near his Orlando, Fla. home, he said on his Web site. In April, he had arthroscopic surgery on the area, and while recovering, sustained a double stress fracture of the left tibia, The New York Times reported Wednesday.

The announcement came two days after Woods' dramatic victory at the U.S. Open in San Diego after a 19-hole sudden death playoff. Despite the win, he had a noticeable limp and often winced after making shots.

Woods said he had hoped to avoid reconstructive surgery until after the season ended. There had been no prior mention of an ACL injury, the newspaper said.

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Americans Have to Wait Until 2011 for Generic Lipitor

Generic versions of the cholesterol drug Lipitor won't be available in the United States until Nov. 30, 2011, under the terms of a patent dispute agreement reached between Pfizer Inc. and Ranbaxy Laboratories Ltd. of India.

"The agreement provides patients with access to a generic product much earlier than if Ranbaxy were unsuccessful in obtaining approval for its product and overcoming the relevant patents," Ian Read, president of worldwide pharmaceutical operations for Pfizer, said in a prepared statement, the Associated Press reported.

Along with giving more certainty to the timing of generic versions of Lipitor, the agreement gives Pfizer more time to develop replacements for Lipitor before generic versions of the drug go on the market.

The deal also permits Ranbaxy to sell generic versions of Lipitor in Australia, Belgium, Canada, Germany, Italy, the Netherlands and Sweden, the AP reported. Pfizer and Ranbaxy also resolved conflicts over Lipitor in Brunei, Malaysia, Peru and Vietnam.

The two companies are still involved in patent infringement litigation over Lipitor in Denmark, Finland, Portugal, Romania, and Spain.

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Certain Gene Variants Boost Levels of Good Cholesterol

One third of people have genes that increase levels of "good" HDL cholesterol and may help fight heart disease, says a study by U.K. and Dutch researchers.

They analyzed the findings of almost 100 studies that included about 147,000 patients and found that people with certain types of the CETP gene have about a 5 percent reduced risk of heart attack, BBC News reported.

The findings lend support to the idea that raising HDL cholesterol levels by influencing CETP activity could help prevent heart disease, said study leader Professor John Danesh.

The study, funded by the British Heart Foundation, was published in the journal Circulation.

"Researchers are questioning whether approaches that raise HDL cholesterol could further prevent heart disease. This suggests that it might have benefits, but that more studies are needed to determine how much (benefit) might be derived," Professor Peter Weissberg, of the British Heart Foundation, told BBC News.

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Obese Women Less Likely to Have Cervical Cancer Screening

Compared to women with average body weight, obese women are less likely to be screened for cervical cancer, say Canadian researchers who analyzed the responses of 38,000 women, ages 20 to 69, who took part in a national survey in 2007.

The more obese a woman was, the less likely she was to have Pap smear testing, CBC News reported.

"Obese women are 30 to 40 percent less likely -- depending on the degree of obesity -- to have recommended cervical cancer screening performed," Raj Padwal, a researcher at the University of Alberta's Faculty of Medicine, said in a prepared statement.

A number of factors may be to blame. For example, Padwal and colleagues found that severely obese women were nearly twice as likely as average-weight women to express fear about cervical cancer screening due to pain, embarrassment or anxiety about the findings, CBC News reported.

A woman's weight didn't have any effect on breast and colon cancer screening.

The study was expected to be published in the August issue of the American Journal of Preventive Medicine.

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AMA Mum on Menthol Cigarette Exemption

The American Medical Associated voted Tuesday to defer comment on a proviso in federal tobacco legislation that would grant an exemption to menthol while banning other cigarette flavor additives such as mint, clove, and vanilla.

The AMA voted "to refer the decision on menthol to its board, effectively silencing the doctors who wanted the organization to speak out against the exemption," the Associated Press reported. The exemption is key to a compromise that would give regulatory control of cigarettes to the U.S. Food and Drug Administration.

While the other additives tend to be favored by younger people, menthol is preferred by more than 75 percent of blacks who smoke. That compares to fewer than 25 percent of whites who smoke, the AP said, citing government estimates.

Former Secretary of Health and Human Services Louis Sullivan, who held the post from 1989 to 1993, is among seven former health secretaries who have written to Congress opposing the menthol exemption.

"If we're banning things such as clove and peppermint, then we should ban menthol," he said. "This bill [if it includes the exemption] will be discriminatory against African-Americans."

But AMA President Dr. Ron Davis is among those who favors keeping the exemption, having said that removing it could threaten passage of the entire bill, the AP reported. "It would change the entire political dynamic," he said.