Health Highlights: Jan. 31, 2005

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

U.S. Adds More Substances to Known Carcinogens List

U.S. health officials have added 17 substances to the list of cancer-causing agents, bringing the total to 246. And for the first time, viruses are listed in the report: hepatitis B, hepatitis C, and some human papillomaviruses that cause common sexually transmitted diseases.

Other new additions to the list include lead and lead compounds, X-rays, and a variety of substances used in textile dyes, paints and inks.

The Report on Carcinogens, Eleventh Edition lists cancer-causing agents in two categories -- "known to be human carcinogens" and "reasonably anticipated to be human carcinogens." The report now contains 58 "known" and 188 "reasonably anticipated" entries. By law, the Secretary of Health and Human Services must publish the report every two years.

Six substances have been added to the "known" category:

Hepatitis B and hepatitis C are viruses that cause acute or chronic liver disease. Human papillomaviruses (HPVs) are viruses that are sexually transmitted; some are listed in the report because studies show they cause cervical cancer in women.

X-rays and gamma-rays are also listed as "known human carcinogens." Of the total worldwide exposure to X-radiation and gamma-radiation, 55 percent is from low-dose medical diagnosis such as bone, chest and dental X-rays, and 43 percent is from natural sources like radon.

The full report is available at http://ntp.niehs.nih.gov.

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Enzyme Linked to Type 2 Diabetes

An enzyme that triggers inflammation has been directly linked to insulin resistance and resulting type 2 diabetes. And inhibiting the enzyme in the body''s immune system might prove to be a new diabetes therapy, according to scientists at the University of California, San Diego School of Medicine.

Their study, published in the February 2005 issue of the journal Nature Medicine, describes research in mice that identifies enzyme IkB kinase β (Ikk-β) as a central coordinator of inflammatory responses in the liver and macrophages, immune system cells that attack infections.

Both control mice and mice with Ikk-β deleted in specific types of cells were fed a high-fat diet that normally causes insulin resistance and type 2 diabetes. While the control mice developed diabetes and insulin-resistant symptoms, mice without the Ikk-β maintained healthy insulin levels.

"The potential for a new diabetes treatment is great," said one of the study''s senior authors, Dr. Jerrold Olefsky, chief of UCSD''s Division of Endocrinology and Metabolism in the Department of Medicine. "An inhibitor of Ikk-β could be used, or an inhibitor of any other molecule in the inflammation pathway."

Diabetes, which affects 18.2 million Americans, is a disease in which the body doesn''t produce or properly use insulin, a hormone needed to convert sugar, starches and other foods into energy for cells.

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New Panel Seeks to End Health Care Disparities

The American Medical Association, the National Medical Association and the National Hispanic Medical Association announced Monday the creation of a commission to end disparities in medical care.

The Commission to End Health Care Disparities, consisting of leaders from the nation''s largest physicians'' organizations and more than 30 health-related groups, said it will work to educate doctors and health professionals about health care disparities while identifying and developing strategies to eliminate gaps in care due to race and culture.

Studies have shown that minority patients experience lower quality health services and are more likely to develop diseases such as cancer, cardiovascular disease and diabetes. To help minority patients get the care they need, the commission has established four committees that will work to raise professional awareness, improve data gathering, increase education and training and promote workforce diversity, according to a statement from the panel.

"The causes of health disparities are complex, and raising awareness is an important step toward ending inequality in care," said AMA President Dr. John C. Nelson.

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Hillary Clinton Collapses During Speech

Sen. Hillary Rodham Clinton collapsed Monday during a speech in Buffalo, N.Y., but recovered quickly from what her aides described as a fainting spell brought on by a 24-hour bout with the flu, NBC News reported.

Clinton, 57, received medical treatment at the private Saturn Club, where she was giving an address on Social Security to a group of women voters. She went on to give another speech later in the day at a nearby college, the network said.

Clinton was speaking to a crowd of 150 people when she briefly lost consciousness, an aide said. "She was weak and needed to sit down. She fainted," said the aide, who spoke anonymously to the Associated Press.

Vincent Tracy, general manager of the Saturn Club, said Clinton walked out of the building a short time later. "I saw her walk out the door by herself; she smiled and said ''thank you,'' " he said.

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Scientists Convert Stem Cells to Muscle-Moving Neurons

Human embryonic stem cells have been successfully coaxed into becoming muscle-controlling neurons that could ultimately offer remedies for spinal cord injuries and conditions like muscular dystrophy, scientists say.

While the University of Wisconsin researchers said it will be years before they could apply the discovery to people, they added that the study proved that lab-grown motor neurons could make muscle cells contract in a petri dish, the Bloomberg news service reported.

The next step, the scientists wrote in the journal Nature Biotechnology, is to inject the neurons into the spinal cords of chicken embryos.

Embryonic stem cells --- master cells that contain the building blocks of life -- have the ability to grow into a diverse range of cells, including bone, muscle, organs or even brain and nerve tissue. But harvesting them has proven controversial, since the human embryos must be destroyed in the process.

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Sexual Orientation Linked to Multiple Genetic Traits

Multiple genes -- not a single gene or sex chromosome -- help determine a person''s sexual orientation, University of Illinois scientists concluded in new research.

The findings, reported in the journal Human Genetics, suggest there is no single "gay gene," but a host of genetic traits that are associated with homosexual behavior. The scientists said environmental factors probably are involved, too.

According to BBC News Online, past research has focused on the X chromosome that''s passed to boys by their mother. The new study examined all 22 pairs of non-sex chromosomes of 456 people from families with two or more gay brothers.

About 60 percent of these brothers shared identical DNA on chromosomes 7, 8, and 10, the study found.

"Our study helps to establish that genes play an important role in determining whether a man is gay or heterosexual, the researchers wrote. "Our best guess is that multiples genes, potentially interacting with environmental influences, explain differences in sexual orientation."