文章来源:未知 文章作者:meng 发布时间:2009-11-09 06:55 字体: [ ]  进入论坛

Tiny metal particles have been shown to cause changes to DNA1 across a cellular2 barrier - without having to cross it.


The study used fibroblast cells to <a href=illuminate3 the cell signalling" width="226" height="170" src="/upimg/091109/4_065939_1.jpg" />
The study used fibroblast cells to illuminate the cell signalling

The nanometre(毫微米) and micrometre(微米) scale particles resulted in an increase of damage to DNA across the barrier via a never-before-seen cell signal process.

Reporting in Nature Nanotechnology, the researchers say the mechanism4 could be both a risk and an opportunity.

They say the preliminary result(预备结果) is relevant as more medical therapies rely on small-scale particles.

For instance, nanoparticle-based approaches are being considered for use to improve MRI images or direct the delivery of cancer drugs.

However, they concede their model system is far simpler than the human body, where the effects will be harder to unpick.

As yet, the researchers are not even certain of the mechanism by which the signalling molecules5 cause damage to DNA.

Communication skills

The team studied the effects of particles made from cobalt(钴) and chromium(铬), either 30 billionths of a metre or four millionths of a metre across.

These metals are used in implants7(植入体) such as artificial hips8 or knees.

They grew a thin, artificial membrane9(人工膜) from human cells and placed the particles on the membrane. Beneath it, they placed fibroblast cells(纤维母细胞), which in the body help to form connective tissue.

Although the team showed that the particles had not crossed the membrane, the fibroblast cells beneath were shown to have about 10 times as many damage sites in their DNA than the case in which no particles were used.

Gevdeep Bhabra, lead author on the research from the Bristol Implant6 Research Centre, explained that cells in close contact are known to exhibit cell-to-cell communication through structures known as gap junctions10 and hemichannels.

"We used a variety of chemicals to block this cell-to-cell signalling and found that in the presence of these blockers, the damage we were seeing was completely prevented," he said.

The team stressed that the concentrations of the particles were thousands of times higher than would be found in the human body, for instance from wear and tear(磨损,折磨) on implants.

As a result, there is no reason to believe that implants pose a risk via the signalling mechanism.

However, its discovery suggests that there is much work to be done to establish if the mechanism that appears to be responsible for the DNA damage is limited to those materials, or can occur in the presence of other materials of a similar size.

That issue is of particular importance as more therapeutic11 and imaging approaches begin to make use of nano-scale materials.

Ashley Blom, head of orthopaedic surgery(矫正外科,骨科) at the University of Bristol, explained that although the signalling could pose a future risk, once understood it could be put to good therapeutic use.

"If the barriers in the human body do work in this way, the first exciting thing is: can we deliver novel therapies across barriers without having to cross them?

"For example, if you have a condition that affects the brain, maybe we could treat you with something that doesn't cross the blood-brain barrier, that does not come in contact with the brain."


1 DNA 4u3z1l     
(缩)deoxyribonucleic acid 脱氧核糖核酸
  • DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
  • Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。
2 cellular aU1yo     
  • She has a cellular telephone in her car.她的汽车里有一部无线通讯电话机。
  • Many people use cellular materials as sensitive elements in hygrometers.很多人用蜂窝状的材料作为测量温度的传感元件。
3 illuminate zcSz4     
  • Dreams kindle a flame to illuminate our dark roads.梦想点燃火炬照亮我们黑暗的道路。
  • They use games and drawings to illuminate their subject.他们用游戏和图画来阐明他们的主题。
4 mechanism zCWxr     
  • The bones and muscles are parts of the mechanism of the body.骨骼和肌肉是人体的组成部件。
  • The mechanism of the machine is very complicated.这台机器的结构是非常复杂的。
5 molecules 187c25e49d45ad10b2f266c1fa7a8d49     
分子( molecule的名词复数 )
  • The structure of molecules can be seen under an electron microscope. 分子的结构可在电子显微镜下观察到。
  • Inside the reactor the large molecules are cracked into smaller molecules. 在反应堆里,大分子裂变为小分子。
6 implant YaBxT     
  • A good teacher should implant high ideals in children.好教师应该把高尚理想灌输给孩子们。
  • The operation to implant the artificial heart took two hours.人工心脏植入手术花费了两小时。
7 implants c10b91e33a66c4b5cba3b091fcdfe0ac     
n.(植入身体中的)移植物( implant的名词复数 )
  • Hormone implants are used as growth boosters. 激素植入物被用作生长辅助剂。 来自《简明英汉词典》
  • Perhaps the most far-reaching project is an initiative called Living Implants From Engineering (LIFE). 也许最具深远意义的项目,是刚刚启动的建造活体移植工程 (LIFE)。 来自英汉非文学 - 生命科学 - 医学的第四次革命
8 hips f8c80f9a170ee6ab52ed1e87054f32d4     
abbr.high impact polystyrene 高冲击强度聚苯乙烯,耐冲性聚苯乙烯n.臀部( hip的名词复数 );[建筑学]屋脊;臀围(尺寸);臀部…的
  • She stood with her hands on her hips. 她双手叉腰站着。
  • They wiggled their hips to the sound of pop music. 他们随着流行音乐的声音摇晃着臀部。 来自《简明英汉词典》
9 membrane H7ez8     
  • A vibrating membrane in the ear helps to convey sounds to the brain.耳膜的振动帮助声音传送到大脑。
  • A plastic membrane serves as selective diffusion barrier.一层塑料薄膜起着选择性渗透屏障的作用。
10 junctions 8d6818d120fa2726af259fc9dc6c7c61     
联结点( junction的名词复数 ); 会合点; (公路或铁路的)交叉路口; (电缆等的)主结点
  • Metals which were mutually soluble would tend to give strong junctions. 可互溶的金属趋向于产生牢固的结合点。
  • Some adhering junctions are present as narrow bands connecting two cells. 有些粘附连接以一窄带的形式连接两个细胞。
11 therapeutic sI8zL     
  • Therapeutic measures were selected to fit the patient.选择治疗措施以适应病人的需要。
  • When I was sad,music had a therapeutic effect.我悲伤的时候,音乐有治疗效力。
TAG标签: metal DNA barrier