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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, June 14 (Xinhua) -- Short sleep duration may contribute to the development or worsening of hyperactivity and inattention during early childhood, suggests a research abstract that was presented Tuesday at SLEEP 2011, the 25th Anniversary Meeting of the Associated Professional Sleep Societies LLC.Results show that less sleep in preschool-age children significantly predicted worse parent-reported hyperactivity and inattention at kindergarten. The sample consisted of approximately 6,860 children, and analyses controlled for gender, ethnicity and family income."Children who were reported to sleep less in preschool were rated by their parents as more hyperactive and less attentive compared to their peers at kindergarten," said lead author Erika Gaylor, senior researcher for SRI International, an independent, nonprofit research institute in Menlo Park, California. "These findings suggest that some children who are not getting adequate sleep may be at risk for developing behavioral problems manifested by hyperactivity, impulsivity, and problems sitting still and paying attention." According to the authors, attention-deficit/hyperactivity disorder (ADHD) is not generally diagnosed until the school-age years. However, the onset of developmentally inappropriate inattention, hyperactivity and impulsivity is often much younger. Sleep problems, particularly difficulty falling asleep and staying asleep, are frequently reported in children and adolescents with ADHD. However, the direction of causation, if any, has been difficult to determine. Longitudinal studies may provide a window into the direction of this complex relationship.Last year at SLEEP 2010, Gaylor reported that having a regular bedtime was the most consistent predictor of positive developmental outcomes at four years of age. Having an earlier bedtime also was predictive of higher scores for most developmental measures.

WUHAN, Aug. 6 (Xinhua) -- A Chinese man nearing 80 years old was recently diagnosed with HIV and doctors say he probably caught the virus through having "frequent unprotected sex."The case is the latest to support the opinions of experts who believe the virus is spreading fast among older Chinese men who have been largely neglected in the country's anti-AIDS campaigns.The latest diagnosed man, whose identity has been concealed for privacy reasons, was admitted to Zhongnan Hospital in central Chinese city of Wuhan with a lingering fever. He was later found to be HIV positive, doctors at the hospital said Friday.The man was widowed in his old age, has no record of blood transfusions, but had an "active unprotected sexual life," they said.Gao Shicheng, a HIV specialist in Zhongnan Hospital, said that HIV/AIDS has started to infect middle-aged and elderly Chinese men who have little or no AIDS prevention knowledge.Gao said this year alone he had diagnosed two senior men with HIV. Both contracted the virus through unprotected sex outside marriage.A recent survey conducted by the Chinese Center for Disease Control and Prevention (China CDC) shows that among the new HIV infections, the percentage of people aged 50 or above with it grew from 7.8 to 14.9 percent. Most of them were male and were found to have contracted the virus through sexual intercourse.Experts say the spread of HIV/AIDS has picked up among older Chinese men in recent years because China's senior citizens have become healthier, more open-minded about sex, and increasingly bored after retirement.They called for anti-AIDS campaigns, which usually target young people with a focus on gays, sex workers, and rural migrants, to also cover seniors in a bid to raise the awareness of HIV/AIDS prevention knowledge.China is fighting a hard battle to contain the spread of HIV/AIDS. According to a UNAIDS estimate, the country had about 740,000 people living with HIV by the end of 2009. Among them, 105,000 were estimated to have AIDS.By the end of August 2010, the cumulative total of reported HIV positives in China was 361,599, with 65,104 recorded deaths.Sex, other than blood transmission or mother-to-child transmission, has become the main channel for the spread of HIV in China.

BEIJING, Sept. 27 (Xinhuanet) -- Scientists have been making great efforts to show how harmful coffee is to us, though no evidence yet. A latest study may be reassuring for coffee-lovers.Women who drink caffeinated coffee are less likely to be depressed than those don't. And the more they drink, the lower risk of developing depression, according to a study published Monday in the Archives of Internal Medicine. Researchers of the study tracked the health of over 50,000 women aged between 30 and 55 in 1996 for a decade and recorded their mental health and coffee intake periodically.They find that women who drank two or three cups of coffee per day were 15 percent less likely than those who drank little or decaffeinated coffee to be depressed.And for those who drank four or more cups, the risk of developing depression reduced by 20 percent.The reason why coffee could protect depression is not clear. But the scientists from the Harvard University speculated that caffeine was the key player. More research is needed to show whether caffeine can ward off depression.It might be that not-depressed people tended to be more activated and the habit of coffee drinking just fit in their lifestyle.However, the depressed ones, who might suffer from sleeplessness, chose not to drink coffee because the caffeine might exacerbate it."There's no need to start drinking coffee," said Dr. Alberto Ascherio, the senior author of the study, "The message is that coffee is safe to drink, with no adverse effects. That's really all that can be said."

BERLIN, June 14 (Xinhua) -- A two-year-old boy became the first child to be killed by the deadly E. coli in Germany on Tuesday, officials said.To date, the terrifying EHEC infection has claimed 36 lives in Germany and one in Sweden.The child, from the northern town of Celle, died in hospital in Hanover of kidney failure and abnormal breakdown of red blood cells, two extreme symptoms of the infection with enterohaemorrhagic E. coli (EHEC), authorities in the state of Lower Saxony said.The boy became the youngest known fatal victim since the outbreak of E. coli in May. His father and 10-year-old brother were also infected with the deadly bacteria, but are recovering, doctors told a local newspaper.The Robert Koch Institute, Germany's national disease prevention and control agency, said on Tuesday that a total of 3, 235 cases had been reported in the country. Among them, 782 people are suffering from haemolytic uraemic syndrome (HUS), a life- threatening illness arising from E. coli, which would destroy human kidney and nervous system.The institute added that the number of new infections is declining sharply in recent days, with only seven reported on Tuesday.German authorities announced on Friday that bean sprouts from a farm in northern Germany were one source of the outbreak, and dropped the previous warning against eating raw cucumbers, tomatoes and lettuce. However, the food panic has caused losses worth hundreds of millions of dollars for European farmers.