太原眼视网膜病变训练模型(江西人体躯干冠状断层解剖模型（男性（) (今日更新中)

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, Aug. 23 (Xinhuanet) -- More than 90 percent of U.S. heart attack patients who need the lifesaving procedure receive it within just 90 minutes of being admitted to the hospital, according to a study released Monday in the journal Circulation.The study on the American Heart Association's journal shows that in 2010, 91 percent of heart attack patients who needed angioplasty were treated within the 90-minute window. While in 2005, 44% were.Researchers analyzed data on more than 300,000 such patients who underwent emergency angioplasty between January of 2005 and October of 2010.The improvement is the result of a nationwide effort between federal agencies, health care organizations and health care providers to improve heart attack care and outcome, said study author Dr. Harlan M. Krumholz, a professor of medicine and epidemiology and public health at Yale University School of Medicine, according to U.S. News reports.

BEIJING, August 1 (Xinhuanet) -- U.S. researchers have discovered a genetic mutation unique to African Americans that links to heighten their asthma risk, according to reports published on Sunday in the journal Nature Genetics.Researchers of University of Chicago found a gene, PYHIN1, and its variations may account for asthma risk in people of African descent. In their study, they examined data from nine previous genome-wide association studies, totaling more than 2 million single nucleotide polymorphisms in 3,246 asthma patients and 3,385 control patient, 1,702 patient-parent groupings, 355 family-based cases, and 468 family-based controls.In the study, the researchers found that between 26 percent and 29 percent of people of African-descent carried at least one copy of the gene.  In particular, one polymorphism of the gene was 34 percent more likely found in African-American and Afro-Caribbean people with asthma.  More interestingly, this variant of the gene is rarely found in Caucasian people and in Latino population, it was found in less than 5 percent.This new variant is part of a family of genes linked with the body's response to viral infections. It is thought to be involved in interferon signaling, which could influence the occurrence of asthma.The team stressed that each gene variant on its own plays only a small role in increasing asthma risk, but that risk could be multiplied when combined with other risk genes and with environmental factors.

MOSCOW, Aug. 3 (Xinhua) -- Two Russian cosmonauts manually launched a mini satellite from the International Space Station ( ISS) during a six-hour spacewalk Wednesday, said the Mission Control center near Moscow.Sergei Volkov and Alexander Samokutyayev, who started the spacewalk with a 20-minute delay, found the 30-kg Kedr has lost one of its two antennas during its delivery to the ISS in January. After consulting with the Mission Control, they have decided to launch the device anyway, Interfax news agency reported.The Kedr satellite, which was made by Russian students, was created to transmit from the orbit greetings in 15 languages about the 50th anniversary of Yuri Gagarin's first space flight. It could also photograph the Earth and re-transmit information from the ISS equipment.During the spacewalk, the cosmonauts were expected to install new stream video equipment on the station's outer surface, and to take pictures holding photos of the founders of Russian space explorations, including Konstantin Tsiolkovski, Sergei Korolyov and Yuri Gagarin.

SAN FRANCISCO, June 20 (Xinhua) -- Google and the British Library announced Monday that the Internet search giant will digitize 250,000 out-of-copyright books from the library's collections, making up to 40 million pages from 1700 to 1870 available to the public online.In a joint statement, the British Library and Google said they will work in partnership over the coming years to deliver the content free through Google Books and the library's website, and full text search, download and reading will be available. Google will cover all digitization costs.The project is going to cover a huge range of printed books, pamphlets and periodicals dated 1700 to 1870, a period of political and technological turmoil, from the Industrial Revolution to the French Revolution, from the introduction of the income tax in Britain and the invention of the telegraph and railway.It will include material in a variety of major European languages and will focus on books that are not yet freely available in digital form online, said the statement.Since December 2004, Google has announced partnership with some 40 high-profile university and public libraries, planning to digitize and make available some 15 million volumes within a decade through Google Books service.The project has triggered controversy as publisher and author associations oppose the plan to put copyrighted titles online in a class action lawsuit.

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