文章来源:未知 文章作者:meng 发布时间:2010-07-09 02:59 字体: [ ]  进入论坛

Having discovered a dramatic increase of an easy-to-detect enzyme1(酶) in the red blood cells of people with diabetes2 and prediabetes(前驱糖尿病) , Johns Hopkins scientists say the discovery could lead to a simple, routine test for detecting the subtle(微妙的,精细的) onset3 of the disease, before symptoms or complications occur and in time to reverse its course. Pilot studies, published online April 22 in Diabetes, show the enzyme O-GlcNAcase is up to two to three times higher in people with diabetes and prediabetes than in those with no disease: "That's a big difference, especially in an enzyme that's as tightly regulated as this one is," says Gerald Hart, Ph.D., the DeLamar Professor and director of biological chemistry at the Johns Hopkins School of Medicine.

Building on their previous research, which showed how an abundant but difficult-to-detect sugar switch known as O-GlcNAc (pronounced oh-GLICK-nack) responded to nutrients4 and stress, the Hopkins team knew this small molecule5(分子) was elevated in the red cells of patients with diabetes. "The question was whether the elevation6 happened in the earliest stages of diabetes and therefore might have value as a diagnostic tool," Hart said.

To find out, Kyoungsook Park, a graduate student of biological chemistry working in Hart's lab, focused on levels of O-GlcNA case, an enzyme that removes O-GlcNAc in red cells. O-GlcNAc modifies many of the cell's proteins to control their functions in response to nutrients and stress. Nutrients, such as glucose7 and lipids(脂肪,油脂) , increase the extent of O-GlcNAc modification8 of proteins affecting their activities. When the extent of O-GlcNAc attached to proteins becomes too high, as occurs in diabetes, it is harmful to the cell.

First, Park purified human red blood cells by depleting9 them of their main constituent10, hemoglobin(血红蛋白) . The samples had been collected by two sources — the National Institute of Diabetes, Digestive and Kidney Diseases, or NIDDK, and Johns Hopkins Diabetes Center in collaboration11 with Christopher D. Saudek, M.D. — and characterized as normal (36 samples), prediabetes (13 samples) and type 2 diabetes (53 samples) according to traditional tests that require patient fasting. Defined as normal hemoglobin A1c with impaired12 fasting glucose(葡萄糖) , prediabetes is an intermediate state of altered glucose metabolism13(新陈代谢) with a heightened risk of developing type 2 diabetes and other associated complications.

Then, she measured and compared the amount of the enzyme protein within the red cells associated with the sugar molecule, O-GlcNAc.

"When I checked the enzyme levels and saw how dramatically different they were between the prediabetic cells and the controls, I thought I did something wrong," Park says. "I repeated the test five times until I could believe it myself."

Hart speculates that in diabetes and prediabetes, it's not a good thing for the increased amount of sugar to be attached to proteins, so the cell is responding by elevating the enzyme that gets rid of it.

"This is an example of how basic research is directly affecting a serious disease," Hart says, adding that his team's pilot studies(初步研究) encourage further investigation14 of a method that potentially could fill the void(空虚,空间) that currently exists for an easy, accurate routine test for prediabetes. "Only a much larger clinical trial will determine if, by measuring O-GlcNAcase, we can accurately15 diagnose prediabetes."


1 enzyme cPozF     
  • Above a certain temperature,the enzyme molecule will become unfolded.超过一定温度,酶分子将会展开。
  • An enzyme that dissolves the fibrin of blood clots.能溶解血凝块中的纤维的酶。
2 diabetes uPnzu     
  • In case of diabetes, physicians advise against the use of sugar.对于糖尿病患者,医生告诫他们不要吃糖。
  • Diabetes is caused by a fault in the insulin production of the body.糖尿病是由体內胰岛素分泌失调引起的。
3 onset bICxF     
  • The drug must be taken from the onset of the infection.这种药必须在感染的最初期就开始服用。
  • Our troops withstood the onset of the enemy.我们的部队抵挡住了敌人的进攻。
4 nutrients 6a1e1ed248a3ac49744c39cc962fb607     
n.(食品或化学品)营养物,营养品( nutrient的名词复数 )
  • a lack of essential nutrients 基本营养的缺乏
  • Nutrients are absorbed into the bloodstream. 营养素被吸收进血液。 来自《简明英汉词典》
5 molecule Y6Tzn     
  • A molecule of water is made up of two atoms of hygrogen and one atom of oxygen.一个水分子是由P妈?f婘??妈?成的。
  • This gives us the structural formula of the molecule.这种方式给出了分子的结构式。
6 elevation bqsxH     
  • The house is at an elevation of 2,000 metres.那幢房子位于海拔两千米的高处。
  • His elevation to the position of General Manager was announced yesterday.昨天宣布他晋升总经理职位。
7 glucose Fyiyz     
  • I gave him an extra dose of glucose to pep him up.我给他多注射了一剂葡萄糖以增强他的活力。
  • The doctor injected glucose into his patient's veins.医生将葡萄糖注入病人的静脉。
8 modification tEZxm     
  • The law,in its present form,is unjust;it needs modification.现行的法律是不公正的,它需要修改。
  • The design requires considerable modification.这个设计需要作大的修改。
9 depleting ae23633b1a5c6c21ae0d93b205d84331     
使大大的减少,使空虚( deplete的现在分词 ); 耗尽,使枯竭
  • Regulations are outlawing certain refrigerants, such as chlorofluorocarbons, which contain ozone-depleting chemicals. 随后出台的政策禁用了部分制冷剂,如破坏臭氧层的氟氯碳化合物。
  • Aging, being a series of continual losses, can be keenly depleting. 老龄化,作为一个系列的连续亏损,可以清楚地消耗。
10 constituent bpxzK     
  • Sugar is the main constituent of candy.食糖是糖果的主要成分。
  • Fibre is a natural constituent of a healthy diet.纤维是健康饮食的天然组成部分。
11 collaboration bW7yD     
  • The two companies are working in close collaboration each other.这两家公司密切合作。
  • He was shot for collaboration with the enemy.他因通敌而被枪毙了。
12 impaired sqtzdr     
adj.受损的;出毛病的;有(身体或智力)缺陷的v.损害,削弱( impair的过去式和过去分词 )
  • Much reading has impaired his vision. 大量读书损害了他的视力。 来自《现代汉英综合大词典》
  • His hearing is somewhat impaired. 他的听觉已受到一定程度的损害。 来自《现代汉英综合大词典》
13 metabolism 171zC     
  • After years of dieting,Carol's metabolism was completely out of whack.经过数年的节食,卡罗尔的新陈代谢完全紊乱了。
  • All living matter undergoes a process of metabolism.生物都有新陈代谢。
14 investigation MRKzq     
  • In an investigation,a new fact became known, which told against him.在调查中新发现了一件对他不利的事实。
  • He drew the conclusion by building on his own investigation.他根据自己的调查研究作出结论。
15 accurately oJHyf     
  • It is hard to hit the ball accurately.准确地击中球很难。
  • Now scientists can forecast the weather accurately.现在科学家们能准确地预报天气。
TAG标签: cells disease diabetes