2011雅思阅读模拟试题精选(共4页).doc
《2011雅思阅读模拟试题精选(共4页).doc》由会员分享,可在线阅读,更多相关《2011雅思阅读模拟试题精选(共4页).doc(4页珍藏版)》请在淘文阁 - 分享文档赚钱的网站上搜索。
1、精选优质文档-倾情为你奉上2011雅思阅读模拟试题精选Why did a promising heart drug fail?Doomed drug highlights complications of meddling with cholesterol.1. The failure of a high-profile cholesterol drug has thrown a spotlight on the complicated machinery that regulates cholesterol levels. But many researchers remain confid
2、ent that drugs to boost levels of good cholesterol are still one of the most promising means to combat spiralling heart disease.2. Drug company Pfizer announced on 2 December that it was cancelling all clinical trials of torcetrapib, a drug designed to raise heart-protective high-density lipoprotein
3、s (HDLs)。 In a trial of 15000 patients, a safety board found that more people died or suffered cardiovascular problems after taking the drug plus a cholesterol-lowering statin than those in a control group who took the statin alone.3. The news came as a kick in the teeth to many cardiologists becaus
4、e earlier tests in animals and people suggested it would lower rates of cardiovascular disease. There have been no red flags to my knowledge, says John Chapman, a specialist in lipoproteins and atherosclerosis at the National Institute for Health and Medical Research (INSERM) in Paris who has also s
5、tudied torcetrapib. This cancellation came as a complete shock.4. Torcetrapib is one of the most advanced of a new breed of drugs designed to raise levels of HDLs, which ferry cholesterol out of artery-clogging plaques to the liver for removal from the body. Specifically, torcetrapib blocks a protei
6、n called cholesterol ester transfer protein (CETP), which normally transfers the cholesterol from high-density lipoproteins to low density, plaque-promoting ones. Statins, in contrast, mainly work by lowering the bad low-density lipoproteins.Under pressure5. Researchers are now trying to work out wh
7、y and how the drug backfired, something that will not become clear until the clinical details are released by Pfizer. One hint lies in evidence from earlier trials that it slightly raises blood pressure in some patients. It was thought that this mild problem would be offset by the heart benefits of
8、the drug. But it is possible that it actually proved fatal in some patients who already suffered high blood pressure. If blood pressure is the explanation, it would actually be good news for drug developers because it suggests that the problems are specific to this compound. Other prototype drugs th
9、at are being developed to block CETP work in a slightly different way and might not suffer the same downfall.6. But it is also possible that the whole idea of blocking CETP is flawed, says Moti Kashyap, who directs atherosclerosis research at the VA Medical Center in Long Beach, California. When HDL
10、s excrete cholesterol in the liver, they actually rely on LDLs for part of this process. So inhibiting CETP, which prevents the transfer of cholesterol from HDL to LDL, might actually cause an abnormal and irreversible accumulation of cholesterol in the body. Youre blocking a physiologic mechanism t
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- 2011 雅思 阅读 模拟 试题 精选
限制150内