CD4 Cell-英语听力

[00:00.10]From VOA Learning English, this is the Health Report. [00:05.37]December 1 marked World Aids Day. [00:10.27]People around the world Join together to celebrate progress in fighting acquired immune deficiency syndrome, [00:20.74]better known as AIDS. [00:23.11]A new device aims to make identification of AIDS easier and to lower the cost of testing in developing countries. [00:33.70]The device is used to count a disease-fighting white blood cells called the CD4 cell. [00:42.45]The human immunodeficiency virus -- [00:45.58]HIV attacks and destroys CD4 cells making patients unable to fight off infection. [00:55.68]Doctors often suggest patients use antiretroviral drugs to help strengthen the body's natural defences for fighting disease. [01:07.68]A CD4 cell count can help doctors decide if the drug treatment is necessary or not. [01:16.75]The count requires a blood sample and a laboratory equipped to study the cells. [01:24.55]This can be difficult to do in some African nations where many people have AIDS but where testing laboratories are in short supply. [01:36.70]Rashid Bashir heads the bioengineering department at the University of Illinois at Urbana-Champaign. [01:46.38]He and his team have developed the new device which they call "lab on a chip". [01:53.82]It is a 3-centimeter-by-4-centimeter cartridge with all the equipment and chemicals needed to perform a CD4 cell count. [02:06.35]"The promise is to bring the lab to the patient rather than the patient to the lab," he said. [02:10.87]The device uses just a drop of blood. [02:14.72]It separates the white cells from the red cells which carry oxygen. [02:20.63]It then counts the CD4 cells immediately. [02:25.43]Rashid Bashir has a financial interest in a business called Daktari Diagnostics. [02:33.30]The company is working to market the "lab on a chip" and develop a hand-held device to read the results. [02:42.24]Xuanhong Cheng is a bioengineering professor at Lehigh University in Pennsylvania. [02:50.83]She is not involved in Mr Bashir's research, [02:54.41]but she says combining processing and identification in one chip is more helpful than other CD4 counters in development. [03:06.37]"A lot of people just look at the detection side. [03:08.94]But if the sample has to be processed using very complicated methods, [03:12.44]then it's still not quite applicable in resource-limited settings," she said. [03:15.74]Ms Cheng says it will be at least a few years before any of those devices is available on the market. [03:25.46]She is also working on developing a CD4 counter. [03:31.22]"The way that we make a device in a lab is very different from industrial manufacturing processes. [03:37.67]So, the process is not as straightforward as some people would think," she said. [03:41.56]There is an urgent need for better CD4 tests, and she says she is happy about the competition. [03:51.48]And that's the Health Report from VOA Learning English. [03:55.53]I'm Milagros Ardin.