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LOS ANGELES, April 2 (Xinhua) -- People taking antidepressants may be more likely to develop thicker arteries which may raise the risk of heart disease and stroke, a new study suggests.Depression can heighten the risk for heart disease, but the effect of antidepressant use is separate and independent from depression itself, according to the study make public by the American Association for the Advancement of Science (AAAS) on Saturday.The data suggest that antidepressants may combine with depression for a negative effect on blood vessels, said study first author Amit Shah, MD, a cardiology fellow at Emory University School of Medicine.Study findings will be presented on April 5 at the American College of Cardiology meeting in New Orleans, according to the AAAS.The study included 513 middle-aged male twins who both served in the U.S. military during the Vietnam War. Twins are genetically the same but may be different when it comes to other risk factors such as diet, smoking and exercise, so studying them is a good way to distill out the effects of genetics.Researchers measured carotid intima-media thickness - the thickness of the lining of the main arteries in the neck -- by ultrasound. Among the 59 pairs of twins where only one brother took antidepressants, the one taking the drugs tended to have higher carotid intima-media thickness (IMT), even when standard heart disease risk factors were taken into account.The effect was seen both in twins with or without a previous heart attack or stroke. A higher level of depressive symptoms was associated with higher IMT only in those taking antidepressants."One of the strongest and best-studied factors that thickens someone's arteries is age, and that happens at around 10 microns per year," Shah said. "In our study, users of antidepressants see an average 40 micron increase in IMT, so their carotid arteries are in effect four years older."Antidepressants' effects on blood vessels may come from changes in serotonin, a chemical that helps some brain cells communicate but also functions outside the brain, Shah said."I think we have to keep an open mind about the effects of antidepressants on neurochemicals like serotonin in places outside the brain, such as the vasculature. The body often compensates over time for drugs' immediate effects," Shah said. " Antidepressants have a clinical benefit that has been established, so nobody taking these medications should stop based only on these results. This isn 't the kind of study where we can know cause and effect, let alone mechanism, and we need to see whether this holds up in other population groups."

WASHINGTON, May 11 (Xinhua) -- Johns Hopkins University researchers have demonstrated that human liver cells derived from adult cells coaxed into an embryonic state can engraft and begin regenerating liver tissue in mice with chronic liver damage.The work, published Wednesday in the journal Science Translational Medicine, suggests that liver cells derived from so- called "induced-pluripotent stem cells (iPSCs)" could one day be used as an alternative to liver transplant in patients with serious liver diseases, bypassing long waiting lists for organs and concerns about immune system rejection of donated tissue."Our findings provide a foundation for producing functional liver cells for patients who suffer liver diseases and are in need of transplantation," says Yoon-Young Jang, assistant professor of oncology at the Johns Hopkins Kimmel Cancer Center. "iPSC-derived liver cells not only can be generated in large amounts, but also can be tailored to each patient, preventing immune-rejection problems associated with liver transplants from unmatched donors or embryonic stem cells." A microsopic view shows human embryonic stem cells in various stages of differentiation into liver cells in this photo taken at Stanford University and released by the California Institute for Regenerative Medicine, March 9, 2009iPSCs are made from adult cells that have been genetically reprogrammed to revert to an embryonic stem cell-like state, with the ability to transform into different cell types. Human iPSCs can be generated from various tissues, including skin, blood and liver cells.Although the liver can regenerate in the body, end-stage liver failure caused by diseases like cirrhosis and cancers eventually destroy the liver's regenerative ability, Jang says. Currently, the only option for those patients is to receive a liver organ or liver cell transplant, a supply problem given the severe shortage of donor liver tissue for transplantation. In addition, mature liver cells and adult liver stem cells are difficult to isolate or grow in the laboratory, she says. By contrast, iPSCs can be made from a tiny amount of many kinds of tissue; and the embryonic stem- like iPSCs can grow in laboratory cultures indefinitely.For the study, Jang and colleagues generated human iPSCs from a variety of adult human cells, including liver cells, fibroblasts ( connective tissue cells), bone marrow stem cells and skin cells. They found that though the iPSCs overall were molecularly similar to each other and to embryonic stem cells, they retained a distinct molecular "signature" inherited from the cell of origin.

BEIJING, March 11(Xinhuanet)-- People with more fat around their waist, often known as “apple shape”, may not have a greater risk of heart attack than those with fatter bottoms and hips, according to a new study published in Lancet as quotted by media reports Friday.This study funded by the Medical Research Council and British Heart Foundation, reviewed 220,000 individual records from 17 countries and monitored the occurrence of heart attacks or strokes based on body mass index (BMI) versus waist-hip circumference. It found that people with "apple-shaped" obesity were at a higher risk of having heart risks compared to those with general obesity as assessed by their BMI.  This contradicts previous claims that "apple shaped" bodies were three times more likely to suffer heart attacks than those with more generally distributed fat.But experts warn obesity is still bad for the heart, no matter where the fat is, and they argue there is confusion about the best way to measure it. "Regardless of how you measure it, being obese is bad for your heart. This study suggests that measuring your waist is no better than calculating your BMI but it's not time to throw away the tape measure just yet, “Dr Mike Knapton, associate medical director at the British Heart Foundation said."We tend to underestimate our body shape and size, so measuring our waist or checking our BMI are both quick and easy ways we can check our health at home."Besides, he also listed some other heart risk factors that we need to think about too, such as blood pressure, cholesterol, diabetes and smoking.

SAN FRANCISCO, April 4 (Xinhua) -- Web exploit toolkits, or " packaged" attack frameworks that can be traded online, are rapidly growing as the top cybercrime weapon due to ease of use and high success rate, a new report has found."When it comes to conducting online crime, exploit toolkits are the weapon of choice for many cyber criminals," said the "2010 Top Cyber Security Risks Report" published by Hewlett-Packard Co. (HP) on Monday.The trend started in 2006 with the release of WebAttacker, considered by many to be the first modern day web exploit toolkit, according to the report.An emerging trend ensued and soon took off, and today the Internet is subjected to hundreds of exploits originating from these toolkits."With the ever-increasing, web-based criminal activity, the number of exploit toolkits has skyrocketed and shows no signs of slowing down," the report stated.Though protecting against attacks originated with web exploit toolkits is becoming increasingly difficult, there are ways to minimize the risk of infection, said the report, noting that one of the most effective defenses is to install patches onto host systems.The report also found that while the number of attacks against known vulnerabilities continues to rise, the number of discovered vulnerabilities has plateaued in 2010."We've discovered that rather than investing resources to uncover new exploits, attackers are focused on current, unpatched vulnerabilities in web applications, social networking sites and Web 2.0 interfaces," Mike Dausin, a manager at HP Digital Vaccine Labs, said in a statement.Data from the report showed that nearly half of all reported vulnerabilities exist in web applications, and third-party plug- ins to content management systems have become the leading cause of web application vulnerabilities.

HAIKOU, Jan. 28 (Xinhua) -- China's aviation authorities on Friday started to allow helicopters to fly in low-altitude airspace over the tourist island of Hainan on a trial basis for the first time. The aim is to eventually open a part of the country's tightly-controlled airspace to private aircraft.Four helicopters were manned by eight pilots from Shanghai-based Zhengyang Investment Group, a leading domestic firm in the general aviation industry. They are expected to conduct test flights in the sky, 1,000 meters above the ground in Hainan in the next two months.The flight test will collect data for low-altitude flying and test the ground control system's response to emergencies, said Zou Jianming, chairman of Zhengyang Investment Group.Hainan is the first place in China to conduct test flights of private aircraft in low-altitude airspace, said Jiang Sixian, deputy governor of the province. Domestic and foreign firms are both welcome to invest in Hainan's general aviation sector to develop world-class tourism here.China's low-altitude airspace is controlled by the Air Force and the Civil Aviation Administration of China (CAAC). Every private aircraft flight needs approval, and the procedure can take from one day up to a week.But last November, the State Council and the Central Military Commission said that part of the low-altitude airspace would be opened to promote the country's general aviation sector, including the purchase and use of private planes.General aviation refers to the part of the aviation industry that excludes flights for military, law enforcement and public transport. China has only 900 aircraft, 80 airports and fewer than 10,000 pilots in the general aviation segment.The market for general aviation in China is valued at only 13 billion yuan (1.98 billion U.S. dollars) but is expected to grow by 15 percent annually until 2020, Hainan aviation officials said.