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LOS ANGELES, June 5 (Xinhua) -- A latest study has found no evidence that screening for ovarian cancer may reduce the risk of dying from the disease, it was reported on Sunday.Screening, however, does increase the likelihood of unnecessary invasive procedures, according to researchers at the University of Utah.The researchers presented their findings at an on-going meeting of the American Society of Clinical Oncology in Chicago, The Los Angeles Times said.Researchers studied 78,216 women, ages 55 to 74, who participated in the National Cancer Institute's Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. Half of the women received the usual care from their OB-gyns, and half received a CA 125 screening every year for six years and an ultrasound every year for four years. They were then followed for a maximum of 12 years.The researchers observed 212 ovarian cancers in the screened group and 176 in the normal care group. There were 118 ovarian cancer deaths in the screened group and 100 in the normal care group. The differences were not statistically significant. Overall, there were 2,924 deaths from all causes in the screened group and 2,914 in the normal care group.But the researchers also observed that 3,285 women had false- positive diagnoses from the screening. Among those, 1,080 underwent surgery that included an oophorectomy (surgical removal of one or both ovaries). Fifteen percent of those who had surgery developed major complications as a result. Overall, 1,771 women in the screened group (7.7 percent) had an oophorectomy, compared with 1,304 in the normal care group (5.8 percent)."We conclude that annual screening for ovarian cancer ... does not reduce disease-specific mortality in women at average risk for ovarian cancer but does increase invasive medical procedures and associated harms," the researchers said in the study.New data presented at the meeting also showed that the widely used cancer drug Avastin can improve treatment of ovarian cancer, The Times said.About 21,880 American women are diagnosed with ovarian cancer each year and about 13,850 die from it, according to the American Cancer Society. Because it produces few symptoms, the disease is typically not diagnosed until it has become advanced and spread throughout the body. As a result, five-year survival is only about 30 percent, and the disease is one of the five most deadly cancers among women. Being able to detect the cancer at an earlier stage when it might be more curable could thus, theoretically, improve the survival rate.The tests most commonly used to detect ovarian cancer include a transvaginal ultrasound to look for tumor masses and a blood test that screens for increased levels of a tumor marker called CA 125.

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.

BEIJING, July 3 (Xinhuanet) -- The Atlantis mission to be launched by NASA on July 8 will not be an end to the space age, as some media suggest.Although it is the final mission of the space shuttle, it will open up "the next chapter" in the United States' space exploration, NASA's administrator Charles Bolden Jr said at the National Press Club in Washington on Friday."When I hear people say - or listen to media reports - that the final shuttle flight marks the end of US human space flight, I have to say . . . these folks must be living on another planet," he said."As a former astronaut and the current NASA administrator, I'm here to tell you that American leadership in space will continue for at least the next half-century because we have laid the foundation for success - and for NASA, failure is not an option," he said.NASA administrator Charles Bolden Jr drew a lot of media attention during his speech at the National Press Club in Washington DC.One of the foundations is the "unprecedented" research capabilities the International Space Station (ISS) now possesses, largely thanks to the space shuttle missions.Although some media imply that "the game will be up" once the ISS is out of orbit in 2020, he said the splendid research results and rich knowledge astronauts and scientists have accumulated through more than 1,200 experiments since 1998 have laid out "a stepping-stone to the rest of the solar system and the tip of what comes next".As NASA turns a new page, it will "focus on deep space exploration", while leaving US private companies to operate low Earth orbit transportation systems for tourism and business, he said.NASA will develop "a deep space crew vehicle and an evolvable heavy-lift rocket," he said. The moon, asteroids and Mars will be the next destinations for humans to live and work, he said."We will maintain and grow US leadership in space and derive all the benefits that flow from it. Tomorrow's space program is taking shape right now," he said.

WASHINGTON, July 8 (Xinhua) -- U.S. President Barack Obama on Friday hailed space shuttle Atlantis' final flight in NASA's shuttle program, saying Americans across the country watched with pride as America reached for the heavens once more.Obama expressed his "sincere gratitude" to Atlantis astronauts and space workers because they "helped our country lead the space age.""Today's launch may mark the final flight of the space shuttle, " Obama said in a statement. "But it propels us into the next era of our never-ending adventure to push the very frontiers of exploration and discovery in space."Friday's flight is the 33rd voyage for Atlantis. Its return to the earth later this month will mark the end of the 30-year shuttle program."What a truly awesome day today," said NASA Associate Administrator for Space Operations Bill Gerstenmaier at the STS- 135 postlaunch news conference. "What you saw is the finest launch team and shuttle preparation teams in the world.""It truly was an awesome, spectacular launch," added Kennedy Space Center Director Bob Cabana, who looked ahead to plans for future development beyond the shuttle program as space station operations continue.Atlantis will be the last shuttle to be retired. Discovery was first in March, followed by Endeavour at the beginning of June. Each shuttle will head to a museum.When the U.S. space shuttle program officially ends later this year, the Russian space program's Soyuz capsule will be the only method for transporting astronauts to and from the station.

BEIJING, May 30 (Xinhuanet) -- Chronic diseases, including heart disease, stroke, cancer, chronic respiratory diseases and diabetes, are the leading cause of mortality in China, representing 85 percent of all deaths, said a senior health official.Kong Lingzhi, deputy director of the disease prevention and control bureau under the Ministry of Health, made the remarks on Saturday at the Forum of Prevention and Control of Chronic Disease."China is facing a great challenge from chronic diseases, which has a serious impact on both the economy and society," said Kong.Each year, about 3.7 million people die before they reach 60 because of chronic diseases. There are currently 200 million hypertension patients and 90 million diabetics in China, official statistics show.To address the challenge, "the government is now drafting an inter-ministerial roadmap for chronic disease intervention, which will set targets, define responsibilities and distribute guidelines for the prevention and control of chronic diseases," she said.The initiative aims to strengthen national and global monitoring and surveillance; scale up the implementation of evidence-based measures to reduce risk factors, such as tobacco use, an unhealthy diet, physical inactivity and harmful alcohol use; and improve access to cost-effective healthcare to prevent complications, disabilities and premature death.But more importantly, the roadmap will help gain attention and support for preventing and controlling chronic diseases and place it high on government working agendas, Kong explained.The government has focused more on addressing instant health crises up to now and policy and funding support for chronic disease control and prevention was very limited, admitted Mao Qun'an, spokesman of the ministry.Given that chronic disease control requires a systematic approach, tasks such as public health education, training for medical workers (especially the grassroots ones) and policies encouraging doctors' involvement need to be carried out, he said.The ultimate goal is to prevent people from getting ill rather than treating diseases, he added.Lei Zhenglong, deputy director of the disease prevention and control bureau, said that to enhance the capacity of medical workers was now the top priority for the initiative.At present, effective disease prevention work usually contradicts the financial interests of clinical doctors, analysts said.A respiratory disease doctor surnamed He with the Peking University People's Hospital said that he came under pressure from the hospital authorities when the number of inpatients declined due to his efforts to inform his patients about chronic disease prevention.