Health Highlights: Aug. 22, 2005

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

Paxil Linked to Adult Suicide Risk, Review Contends

The antidepressant Paxil is linked to a higher risk of suicide attempts in adults, according to a review of 16 studies by researchers in Norway.

The review, published in BMC Medicine journal, looked at adult patients in studies comparing the medicine with a placebo. The researchers, led by Ivar Aursnes and colleagues at the University of Oslo, found seven suicide attempts among those taking Paxil (paroxetine), compared with one among those taking a placebo, they said in an e-mailed statement to Bloomberg news.

In April, European health regulators warned that GlaxoSmithKline''s Paxil, Eli Lilly & Co.''s Prozac and other antidepressants shouldn''t be used to treat children due to a risk of suicide. Aursnes said his study may persuade doctors and regulators to more closely monitor all use of the drug.

Glaxo officials, who hadn''t seen the study, said they will review the paper, which looked at 916 patients taking Paxil and 550 patients on placebo.

"These conclusions in no way reflect the picture that has been built up about the benefits and risks of paroxetine in adults through an extensive clinical trials program involving 24,000 patients," Glaxo spokesman Chris Hunter-Ward said.

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Newly Identified Germ May Cause Child Respiratory Infections

Swedish researchers say they have identified a virus that may be responsible for many of the pediatric lower respiratory infections now classified as "unknown origin."

Currently, scientists at the Karolinska Institute say, a cause for up to 40 percent of the lower respiratory infections that affect children can''t be determined. But in studying hundreds of respiratory tract samples from a pediatric infectious disease ward, they used sophisticated DNA testing to identify a parvovirus tentatively named HBoV.

Writing in the current issue of the Proceedings of the National Academy of Sciences, the researchers said 17 of the samples tested positive for HBoV.

The scientists also suggested that the DNA screening methods they used to identify and test for the virus be used to reveal other germs that have yet to be identified.

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New Blood Test Furthers Personalized Medicine

The U.S. Food and Drug Administration has approved a new blood test that will make it easier for doctors to prescribe certain drugs based on a person''s genetic profile, the agency said in a statement issued Monday.

The Invader UGT1A1 Molecular Assay detects a genetic variation that determines how a particular body processes certain drugs. Doctors can use the results to help determine dosing information and whether a person might be subject to dangerous drug reactions, the agency said.

The newly approved test was studied in 66 patients who received a colorectal cancer treatment called irinotecan. The research revealed that participants with a certain genetic variant had five times greater risk of irinotecan toxicity (poisoning) than those without the genetic trait, the FDA said.

The new test is produced by the Madison, Wisc., firm Third Wave Technologies, Inc.

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Gene Fragments Could Fight SARS

As reported by the Associated Press, genetic material called interfering RNA could be a key weapon against severe acute respiratory syndrome (SARS), a team of Chinese and U.S. researchers reported Sunday.

SARS, which first emerged in 2002, raised global health alarms and killed 774 people worldwide before it was contained.

Reporting in Nature Medicine, researchers led by Patrick Yu of Intradigm Corp., of Rockville, Md., say tiny gene snippets known as siRNA effectively silenced specific genes in the SARS genome-- reducing existing infection in monkeys and helping protect the animals from new SARS infections.

All of the treated monkeys did show some symptoms, but they were greatly reduced after treatment with an siRNA nasal spray, the researchers said. Throat samples taken four days after infection found evidence of SARS virus in only a quarter of animals receiving the gene-based treatment.

Speaking to the AP, SARS expert Dr. Krishan K. Pandey of the University of Minnesota, said the success of the treatment in monkeys is impressive, since they are such close genetic relatives of humans. "Another strong point of this study is the successful use of siRNA in prophylactic treatment of SARS, which is surely a great thing if it is successful in humans," he said.

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Immune Discovery Could Lead to Blood Cancer Vaccine

An experimental vaccine appears to prime the human immune system to fight an aggressive form of lymphoma, even if prior therapy has depleted nearly all the B cells thought necessary to this type of immune response.

Reporting in Nature Medicine on Sunday, researchers at the National Cancer Institute in Bethesda, Md, and the M.D. Anderson Cancer Center in Houston, found that only a tiny number of B cells were needed to trigger an effective response in killer T cells.

Before this study, experts assumed that relatively high amounts of both cell types were needed to spur a vaccine-like attack on lymphomas.

"This is the first human cancer vaccine study to see T-cell responses in the absence of B cells, and this paves the way to use vaccines in a number of hematological cancers that are treated by eliminating diseased B cells," study lead author Dr. Sattva Neelapu, of the M.D. Anderson Cancer Center, said in a prepared statement.

His team''s Phase I trial of the vaccine against deadly mantle cell lymphoma noted T-cell responses following the third vaccination. Furthermore, "an antibody response to the tumor produced by recovering B cells was seen after the fourth or fifth vaccination," Neepalu said.

While some patients have relapsed while on the therapy, others have survived, suggesting the vaccine "did modify the natural history of the disease," the Texas researcher said. His team is now working to improve the vaccine with the aim of testing it further.