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, |6 f8 G$ ?( u2 E"But just getting iPS cells with a mutant DMPK gene may not fully mimic the complicated triplet-repeat damage that occurs in type 1 myotonic dystrophy, because of the complex genomic and epigenetic changes associated with reprogramming. Also, iPS cells may not in any case help us understand the critical events in very early development that lead to the myotonic dystrophy syndrome."--Marc Peschanski, director of the Institute for Stem Cell Therapy in Evry.. }: S2 }4 I- w2 @ y
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"Processing our dinner every day is a tough job so the lining of our intestines quickly get worn out. To keep the intestine working stem cells in little pockets along the surface replace the
0 ^' Y: k. J Wlining, cell by cell, about once a week. We already knew these stem cells existed for a while we didn't know much about them because it was difficult to distinguish them from all of the other types of cells in our intestines. Our team was able to single them out and study them because we discovered a gene that is only turned on in these particular stem cells."--Professor Nick Barker of the Institute of Medical Biology in Singapore.! V h3 G8 O( O
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"Everybody is trying to understand what 5-hydroxymethylcytosine is doing. Is it an intermediate, or is it an end product? What is its biological function?...It's the first time we have the whole picture of where this new modification is in embryonic stem cells. We found that its role in regulating transcription is complicated. It's not simply activating or repressing genes - it depends on the context."--University of North Carolina at Chapel Hill biochemist Yi Zhang,2 M3 S: E) b5 w3 Q' L3 P- u
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"It's smaller than a grain of sand, it has no structure, no blood. But it allows us to do things that were previously impossible."--Dr. John Wagner, pediatrics professor and director of the division of hematology-oncology and blood and marrow transplantation at the University of Minnesota's Stem Cell Institute.
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4 M( `5 C" I6 R* [9 [9 v"Often when you produce stem cells in the lab, you want them to take on a particular set of characteristics – say, those of a nerve cell. But it can be really difficult to get 100% of cells that are the same – there are often a significant minority of cells with other characteristics. We think this might be because inside an animal it is crucial that stem cells generate the right numbers of the right types of cells and in the right locations, and there are mechanisms that ensure this is the case. Encouraging a cell down one route in the lab may well trigger activation of these balancing mechanisms, and thus act to limit the proportion of cells that go down this route. For this reason, understanding the mechanisms generating this balance is crucial."--Dr Robert Kelsh from the University of Bath.3 F3 ^+ f9 W; }& I
/ r9 b5 D3 _$ q"This has strong policy implications. It has not ever been a scientifically driven argument that iPS cells are a worthy and complete substitute for embryonic stem cells. Those arguments were always made based on political and religious opposition to embryonic stem cells."--Dr. George Daley of the Harvard Stem Cell Institute and Harvard Medical School., C" V( O( ]1 X, }; m$ G4 q4 b- X
7 r5 }3 H, [% b; U9 h/ o& ]* q0 D“In adult stem cell research money is flowing like a river. [In contrast], money going into embryonic stem cell research is resulting in nothing but dead embryos.”--Scott Fischbach, executive director of Minnesota Citizens Concerned for Life, an affiliate of the National Right to Life Committee.' |/ p7 |* d- u5 d- H! W! U' j
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“This work provides an exciting new perspective on what makes embryonic stem cells special. It shows how the balance between opposing epigenetic marks is important for the ability of stem cells to differentiate into different tissues. We may be able to use the new epigenetic mark, hydroxymethylation, for improved strategies for reprogramming any cell into a stem cell, and hence in regenerative medicine.”--Professor Wolf Reik at the Babraham Institute.
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* S2 Z2 h- G' S) a, g$ l0 b“We perform a bypass to reroute blood flow around blockages in the coronary arteries. The injection of stem cells might enhance the bypass surgery by causing the formation of new blood vessels at the site of injection.”--Dr. Brian Bruckner, cardiac surgeon at the Methodist DeBakey Heart & Vascular Center. ' ]( r9 z6 l. Y+ `! R8 v
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"Mesenchymal stem cells have several advantages. First and foremost, they are universal, basically akin to blood group O - the universal red cell donor. MSCs are able to adapt to any transplant environment and will not be rejected. They were discovered by Soviet scientist Alexander Friedenstein, who was also first to successfully multiply these cells. Our institute has been studying them since the 1970s; we learned how to cultivate Mesenchymal stem cells but at first used them solely for diagnostic purposes, unaware of their healing capabilities."--Head of the department of cell and experimental radiation therapy Dr. Anatoly Konoplyannikov.
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( k% r3 `6 }+ V$ ~8 ^. N4 mThis issue:
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发表于 2011-4-10 21:12
