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Science and technology
科學和技術
Medical technology
醫療技術
A not-so-hard graft
一個不那么難的移植
Transplantable blood vessels can now be grown as desired
可移植的血管現可隨意培育
The old-fashioned way
古老的方式
ANOTHER advance in the emerging technology of regenerative medicine has just been announced.
新興再生醫學技術的又一項進展剛剛被公布。
It should soon be possible to make blood vessels that can be stored and used off the shelf for surgery that requires arteries or veins to be bypassed.
該項技術應該不久就可能制造血管，這種血管可以儲存，需要進行繞過動靜脈的外科手術時可以現貨供應。
The vessels, prototypes of which are described this week in a paper in Science Translational Medicine, are made by Humacyte, a small firm based in Durham, North Carolina, that was founded by Shannon Dahl, the paper's principal author, and two colleagues.
本周《科學轉化醫學》上的一篇論文描述了這種血管的原型，它是由北卡羅來納州達勒姆的一家小公司Humacyte制造的，而公司的創立者為該論文的主要作者夏倫?達爾和其兩位同事。
The recipe Dr Dahl and her colleagues concocted begins with smooth-muscle cells.
達爾博士及其同事的制做方法是由平滑肌細胞開始。
Smooth muscle is different from the familiar sort that cloaks bones and enables bodily movement.
平滑肌不同于我們熟悉的那種包覆骨骼并使身體運動的肌肉。
It is a component of organs such as the gut and the blood vessels that sometimes need to change shape while they are functioning.
它是腸道和血管等器官的組成部分，這些器官有時需要改變形狀才能行使功能。
To make artificial blood vessels the team took smooth-muscle cells from fresh corpses and cultured them on tubular scaffolds made of a material called polyglycolic acid.
為了制造人造血管，這個小組從新鮮尸體上采集平滑肌細胞，將其放在聚羥基乙酸材料制成的管式支架上培養。
Grown this way, smooth muscle secretes collagen, a structural protein that is, among several other things in the body, an important component of the walls of blood vessels.
采取這種方式生長，平滑肌可分泌膠原，一種結構蛋白，是人體中除其它幾種物質外組成血管壁的重要成分。
The polyglycolic acid degrades spontaneously over the course of a few weeks with the consequence that it is, in effect, replaced by the collagen.
聚羥基乙酸在幾個星期內自發降解，實際結果就是被膠原蛋白取代了。
The result is a tube of the length and diameter of the original scaffold, that is composed of collagen and smooth-muscle cells—a structure similar to a natural blood vessel.
所得物保持原來支架的長度和直徑，由膠原蛋白和平滑肌細胞組成，其結構類似天然血管。
Transplanting that into a patient, however, would risk provoking an immune reaction, since the muscle cells are foreign tissue.
不過將其移植到患者身上會有引發免疫反應的風險，因為人造血管上的肌肉細胞是外來組織。
To get around this, Dr Dahl and her colleagues wash the muscle cells away with a detergent, leaving just the collagen.
為了避免這個問題，達爾博士和其同事用洗滌劑洗去這些肌肉細胞，只留下膠原蛋白。
Though the end product is a nonliving simulacrum of a blood vessel rather than an artificial version of the real, biologically active thing, experiments on animals suggest that it works well enough to substitute for a diseased natural vessel.
雖然最終產品是無生命的模擬血管，而不是真正的、具有生物活性的人造血管，但是動物實驗表明，它足以代替患病的天然血管。
It can also act as a tap from which the blood of people whose kidneys have failed might be drawn for dialysis.
它也可以充當腎病患者龍頭，引出患者的血液進行透析。
At the moment, the optons for either of these things are limited.
目前，適合這些用途的任一用途的血管選擇都很有限。
The best approach is to use a length of vessel taken from elsewhere in the patient's body.
最好的方法就是采用來自病患身體其它部位的一段血管。
But that requires such transplants to be healthy themselves—and each length of transplanted vessel can be used only once.
但這要求這樣的移植對患者無害，而且每根移植的血管只能使用一次。
Synthetic vessels made of Teflon exist, but they are prone to infection and blockage by blood clots, and tend to work for only a few months.
現已存在聚四氟乙烯制成的人造血管，但它們很容易感染和形成血栓，且往往只能起幾個月的作用。
The animal experiments suggest the new, all-collagen vessels are capable of lasting at least a year without noticeable deterioration.
動物實驗表明，新型全膠原蛋白的血管有能力至少維持一年而沒有明顯惡化。
They are also, once implanted, able to remodel themselves in ways that improve their function—changing shape in response to blood flow, being colonised by cells from the patient's body, and showing signs of incorporating elastin, another structural protein found in natural vessels.
一旦植入，它們也能按照提高其功能的方式自我改造—針對血流改變形狀，讓病患的身體細胞在其上生長，并顯示出混合了天然血管中發現的另一個結構蛋白彈性蛋白的跡象。
Also, if kept in a suitable saline buffer at 4°C, they can be transplanted a year after they were made without a perceptible degradation of their properties.
此外，如果保存在4 ° C合適的鹽水緩沖液中，它們可以在制成一年后被移植，而沒有可察覺的性能退化。
So, if human trials confirm these results, the surgical-repairer's toolkit will have acquired a useful additional instrument—and the age of the cyborg will be just that little bit nearer.
所以，如果人體試驗證實了這些結果，外科修復師的工具包就會增添一個有用的額外工具，且生控體系統時代的來臨就又接近了一點點。
