国产av不卡一区二区_欧美xxxx做受欧美_成年人看的毛片_亚洲第一天堂在线观看_亚洲午夜精品久久久中文影院av_8x8ⅹ国产精品一区二区二区_久久精品国产sm调教网站演员_亚洲av综合色区无码一二三区_成人免费激情视频_国产九九九视频

Download

For the first time, doctors have successfully transplanted a vein grown with a patient's own stem cells, another example of scientists producing human body parts in the lab.

In this case, the patient was a 10-year-old girl in Sweden who was suffering from a severe vein blockage to her liver. Last March, the girl's doctors decided to make her a new blood vessel to bypass the blocked vein instead of using one of her own or considering a liver transplant.

They took a 9-centimeter section of vein from a deceased donor, which was stripped of all its cells, leaving just a hollow tube. Using stem cells from the girl's bone marrow, scientists grew millions of cells to cover the vein, a process that took about two weeks. The new blood vessel was then transplanted into the patient.

Because doctors used her own cells, the girl did not have to take any drugs to stop her immune system from attacking the new vein, as is usually the case in transplants involving donor tissue.

"This is the future for tissue engineering, where we can make tailor-made organs for patients," said Suchitra Sumitran-Holgersson of the University of Gothenburg, one of the study's authors.

She and colleagues published the results of their work online on Thursday in the British medical journal Lancet. The work was paid for by the Swedish government.

The science is still preliminary, and one year after the vein was transplanted, it needed to be replaced with another lab-grown vein when doctors noticed the blood flow had dropped.

Experts from University College London raised questions in an accompanying commentary about how cost-effective the procedure might be, citing "acute pressures" on health systems that might make these treatments impractical for many patients.

Sumitran-Holgersson estimated the cost at between $6,000 and $10,000.

Patients with the girl's condition are usually treated with a vein transplant from their own leg, a donated vein or a liver transplant. Those options can be complicated in children, and using a donated vein or liver also requires taking anti-rejection medicine.

Since her first transplant, the girl, who was not identified, has grown 6 cm and gained weight. Her parents say she is much more focused, articulate and physically active, Sumitran-Holgersson said.

"She was always tired and hardly went to school before," she said. "Last week, her father said she did somersaults for the first time."

Other experts predicted that it should soon be possible for doctors to build arteries for patients.

（中國日報網英語點津 Helen 編輯）

About the broadcaster:

Nelly Min is an editor at China Daily with more than 10 years of experience as a newspaper editor and photographer. She has worked at major newspapers in the U.S., including the Los Angeles Times and the Detroit Free Press. She is also fluent in Korean.