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LOS ANGELES, July 18 (Xinhua) -- U.S. scientists have proven that oncogenes can change normal cells into stem-like cells, paving the way to a safer and more practical approach to treating diseases like multiple sclerosis and cancer with stem cell therapy.In a collaborative study, researchers from the Keck School of Medicine of the University of Southern California (USC), and the Children's Hospital of Orange County (CHOC) in California and Good Samaritan Hospital Medical Center in New York have successfully converted human skin cells into brain cells by suppressing the expression of p53, a protein encoded by a widely studied oncogene. This suggests that p53 mutation helps determine cell fate -- good or bad -- rather than only the outcome of cancer.Oncogenes are generally thought to be genes that, when mutated, change healthy cells into cancerous tumor cells.Study findings were appearing Monday on the website of the American Association for the Advancement of Science (AAAS)."The reality may be more complicated than people think," said Jiang F. Zhong, Ph.D., assistant professor of pathology at the Keck School. "What is a stem cell gene? What is a cancer gene? It may be the same thing.""When you turn off p53, people think the cell becomes cancerous because we tend to focus on the bad thing," Zhong said. "Actually, the cell becomes more plastic and could do good things, too. Let's say the cell is like a person who loses his job (the restriction of p53). He could become a criminal or he could find another job and have a positive effect on society. What pushes him one way or the other, we don't know because the environment is very complicated."Stem cells can divide and differentiate into different types of cells in the body. In humans, embryonic stem cells differentiate into three families, or germ layers, of cells. The reasons why and how certain stem cells differentiate into particular layers are not clearly understood. However, from those layers, tissues and organs develop. The endoderm, for example, leads to formation of the stomach, colon and lungs, while the mesoderm forms blood, bone and heart tissue. In its study, Zhong's team examined human skin cells, which are related to brain and neural cells from the ectoderm.When p53 was suppressed, the skin cells developed into cells that looked exactly like human embryonic stem cells. But, unlike other man-made stem cells that are "pluripotent" and can become any other cells in the body, these cells differentiated only into cells from the same germ layer, ectoderm."IPSCs (induced pluripotent stem cells) can turn into anything, so they are hard to control," Zhong said. "Our cells are staying within the ectoderm lineage."Zhong said he expects that suppressing other oncogenes in other families of cells would have the same effect, which could have critical significance for stem cell therapy. Future research should focus on determining which genes to manipulate, Zhong said.The study is slated to appear in the Proceedings of the National Academy of Sciences later this month, according to AAAS.

WASHINGTON, Sept. 26 (Xinhua) -- Older people with low blood levels of vitamin B12 markers may be more likely to have lower brain volumes and have problems with their thinking skills, according to researchers at Rush University Medical Center in Chicago.The results of the study will be published Tuesday in Neurology, the medical journal of the American Academy of Neurology.Foods that come from animals, including fish, meat, especially liver, milk, eggs and poultry are usual sources of vitamin B12.The study involved 121 older residents of the south side of Chicago over the age of 65. They had blood drawn to measure levels of vitamin B12 and B12-related markers that can indicate a B12 deficiency. The same subjects took tests measuring their memory and other cognitive skills.An average of four-and-a-half years later, MRI scans of the participants' brains were taken to measure total brain volume and look for other signs of brain damage.Having high levels of four of five markers for vitamin B12 deficiency was associated with having lower scores on the cognitive tests and smaller total brain volume."Our findings definitely deserve further examination," said Christine Tangney, associate professor at Rush University Medical Center and lead author of the study. "It's too early to say whether increasing vitamin B12 levels in older people through diet or supplements could prevent these problems, but it is an interesting question to explore. Findings from a British trial with B vitamin supplementation are also supportive of these outcomes."On the cognitive tests, the scores ranged from -2.18 to 1.42, with an average of 0.23. For each increase of one micromole per liter of homocysteine -- one of the markers of B12 deficiency -- the cognitive scores decreased by 0.03 standardized units or points.Tangney noted that the level of vitamin B12 itself in the blood was not associated with cognitive problems or loss in brain volume. "Our findings lend support for the contention that poor vitamin B12 status is a potential risk factor for brain atrophy and may contribute to cognitive impairment," said Tangney.

BEIJING, Aug. 14 (Xinhua) -- Gary Locke, the newest U.S. ambassador to China, promised on Sunday to promote bilateral cooperation and understanding between the two countries.Acknowledging challenges in the "important and complex diplomatic and economic bilateral relationship" between the two countries, Locke said he looks forward to working with the Chinese government to expand bilateral cooperation and collaboration.He made the remarks at a press conference held on Sunday afternoon, his first public appearance since arriving in Beijing on Friday evening. Locke's wife Mona Lee and their three children accompanied him at the conference.Speaking about the things he hopes to accomplish over the next several months, Locke said the most important thing will be "to promote stronger and better understanding between the U.S. and China.""This must be done so that more people in the United States understand China, its history, its contributions to world civilization, its challenges and the amazing progress China has made in such a short time," he said.Locke also stressed China's "unique history, culture, and philosophy," which he said must be understood if the two countries wish to forge a more cooperative relationship.Locke, a Democrat, was elected as Washington state's 21st governor in 1996, becoming the first Chinese-American governor in U.S. history. He won reelection in 2000. President Obama nominated Locke as Commerce Secretary in February 2009.

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