[国际新闻] 世界首只「人羊」诞生

日月光

近年来，科学界在将人类与动物细胞混合进行研究的问题上吵得不可开交，反对者有之，我行我素者也有之。英国报章称，美国科学家经过几年实验，终于培育出了世界上第一只人兽混种绵羊，它的体内含有15%的人类细胞。 人在德国 社区) j) {* n9 S* L

9 u  |' s/ C0 f" L: O# H9 E混种绵羊将成「活体工厂」
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. Y$ M4 M( ~5 Q据英国《每日邮报》3月25日报道，美国内华达大学的伊斯梅尔·赞加尼教授领导的研究小组用了7年时间完善这项技术。目前绵羊体内的人类细胞比例达到15%，动物细胞比例爲85%。
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这项研究的最终目标是在绵羊体内「种」出病人需要的各种可移植器官。过程包括从病人的骨髓中提取干细胞，然后将其注入一只绵羊的胚胎腹膜中，等胚胎发育成形、羊羔降生，人类干细胞也会通过新陈代谢系统进入绵羊所有器官的循环系统。两个月后，绵羊含有部分人类基因的肝脏、心脏和大脑就会发育健全，这时就能「回收利用」了。
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赞加尼教授表示，从人体骨髓提取不到56克的干细胞就足以注入10个绵羊胚胎，这样就能培养出多个可供移植的器官，假如第一个器官移植失败，还有很多备用器官。这样，人兽混种绵羊将成爲「活体工厂」，爲人类提供组织器官，同时也可用于药物实验。 . A& |5 L, H1 \4 T
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安全和伦理问题令人担忧 4 m7 l1 u( a' h- S9 r( A" }+ r+ L! Z2 [

$ I0 C, j. t0 ]/ t; g目前，全世界有大量的病人急需器官移植，需求量远大于捐赠量，而且供体与病人的各方面条件也未必匹配。据统计，仅英国就有7168人在等待器官移植，其中三分之二的人可能在找到合适的器官前就会死去。如果赞加尼教授的最终目标得以实现，人类将彻底解决可移植器官供应短缺的问题。
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然而，不少科学家质疑，认爲这将大大增加人类传染动物病毒的风险。研究生物学趋势的帕特里克·狄克逊教授表示：「许多动物身上的隐性病毒将会给人类带来一场‘生物梦魇’。突变性动物病毒是真正的威胁，我们已经见识过艾滋病病毒的威力了。」 # W8 f4 O8 N. u; h5 i) c

4 A4 V$ M* L1 N% Q% J还有不少动物权利保护人士也担心，当人、羊细胞混杂在一起时，会形成新的融合细胞，并诞生兼具人类与绵羊特征的混种怪兽。对此，赞加尼教授解释说，将人体细胞注入到早期的绵羊胚胎不会导致融合细胞的出现。从目前的观察来看，研究人员没有发现混种绵羊表现出除绵羊以外的其它动物的行爲。
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1 [/ \) `& Y) H7 m+ }大衆网-齐鲁晚报25日报道

日月光

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SCIENTISTS have created the world's first human-sheep chimera - which has the body of a sheep and half-human organs.
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The sheep have 15 per cent human cells and 85 per cent animal cells - and their evolution brings the prospect of animal organs being transplanted into humans one step closer.
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Professor Esmail Zanjani, of the University of Nevada, has spent seven years and £5m  ($A12m) perfecting the technique, which involves injecting adult human cells into a sheep's foetus.
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- d1 D4 U5 g+ S6 h) r2 f; m9 ]3 Y; GHe has already created a sheep liver which has a large proportion of human cells and eventually hopes to precisely match a sheep to a transplant patient, using their own stem cells to create their own flock of sheep.
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The process would involve extracting stem cells from the donor's bone marrow and injecting them into the peritoneum of a sheep's foetus.
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+ Z6 p) L$ \- ]* e& F; uWhen the lamb is born, two months later, it would have a liver, heart, lungs and brain that are partly human and available for transplant.
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"We would take a couple of ounces of bone marrow cells from the patient," Prof Zanjani told Britain's Mail on Sunday. " o9 F& Y$ \: J/ J

% e- L$ d+ K$ l2 z* B"We would isolate the stem cells from them, inject them into the peritoneum of these animals and then these cells would get distributed throughout the metabolic system into the circulatory system of all the organs in the body. 6 N2 i$ t- t1 a1 k

: r5 `& r( j$ N6 T! u"The two ounces of stem cell or bone marrow cell we get would provide enough stem cells to do about ten foetuses. So you don't just have one organ for transplant purposes, you have many available in case the first one fails." * l8 K: r: V6 J3 ?7 ]& Q
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At present 7,168 patients are waiting for an organ transplant in Britain alone, and two thirds of them are expected to die before an organ becomes available.
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/ b* p: V4 I4 E2 s2 V$ j& O" tScientists at King's College, London, and the North East Stem Cell Institute in Newcastle have now applied to the HFEA, the Government's fertility watchdog, for permission to start work on the chimeras. 人在德国 社区0 J7 t0 ^( I0 z+ A/ L
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But the development is likely to revive criticisms about scientists playing God, with the possibility of silent viruses, which are harmless in animals, being introduced into the human race. 人在德国 社区) k( ^/ k! l& _# _3 x% @7 j

2 D2 h' T& l; Q7 J5 mwww.csuchen.deDr Patrick Dixon, an international lecturer on biological trends, warned: "Many silent viruses could create a biological nightmare in humans. Mutant animal viruses are a real threat, as we have seen with HIV." www.csuchen.de% N" Y8 W3 F+ n

+ L- u: W6 L! `# `7 eAnimal rights activists fear that if the cells get mixed together, they could end up with cellular fusion, creating a hybrid which would have the features and characteristics of both man and sheep. www.csuchen.de$ j% l: [1 M+ M% K" Q* s0 e1 \
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But Prof Zanjani said: "Transplanting the cells into foetal sheep at this early stage does not result in fusion at all."

日月光

中新网洛杉矶3月25日电 (记者 贾国荣)据美国媒体3月25日报道，世界第一只人兽混种羊在美国内华达大学的伊斯梅尔·赞加尼教授领导的研究小组诞生,目前羊体内的人类细胞比例达到15%，动物细胞比例为85%。www.csuchen.de4 d" c& X; K4 m: e
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　　研究小组用七年时间终于培育出人兽混种羊,这项研究的最终目标是在绵羊体内“种”出病人需要的各种可移植器官。包括从病人骨髓中提取干细胞，然后将其注入绵羊的胚胎腹膜中，等胚胎发育成形、羊羔降生，人类干细胞也会通过新陈代谢系统进入绵羊所有器官的循环系统。两个月后，绵羊含有部分人类基因的肝脏、心脏和大脑就会发育健全，这时就能为人类利用了。' I% X: Z  u' e# D

4 G6 `7 A& N" ^: v! Y6 z　　赞加尼教授表示，从人体骨髓提取不到56克的干细胞就足以注入10个绵羊胚胎，这样就能培养出多个可供移植的器官，假如第一个器官移植失败，还有很多备用器官。这样，人兽混种绵羊将成为“活体工厂”，为人类提供组织器官，同时也可用于药物实验。
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　　但是,这一技术正在科学界引起激烈争论,后果难说。/ e' |& {* ?( n9 L: b( Z# m

: F1 R- X( }9 a[ 本帖最后由 日月光 于 2007-3-26 12:22 编辑 ]