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Tag Archive: Stem cell


The cells, made with cloning technique behind Dolly the sheep, have the potential to regenerate damaged organs and tissues

Cloning technique: a donor egg before nucleus extraction

A human egg before nuclear extraction and fusion with a skin cell. The resulting embryonic stem cells were genetically identical to the skin donor. Photograph: Oregon Health & Science University

Scientists have used the cloning technique that led to Dolly the sheep to turn human skin into embryonic stem cells – which can make any tissue in the body.

The US team overcame technical problems that had frustrated researchers for more than a decade to create batches of the body’s master cells from donated skin.

The work will spark fresh interest in the use of cloning in medical research, and reignite the controversy over a procedure that demands a supply of human eggs, and the creation and destruction of early stage embryos. The US group employed the technique to make embryonic stem cells that were genetically matched to individuals. Such cells could be used to study diseases in exquisite detail, and regenerate damaged organs and tissues.

“Our finding offers new ways of generating stem cells for patients with dysfunctional or damaged tissues and organs,” said Shoukhrat Mitalipov at Oregon Health and Science University. “Such stem cells can regenerate and replace those damaged cells and tissues and alleviate diseases that affect millions of people.”

Dolly was born in 1996 after researchers led by Sir Ian Wilmut in Edinburgh created an embryo by fusing a cell from a sheep’s udder with an egg that had had its nucleus removed. The embryo was a clone – genetically identical to the adult sheep the udder cell came from.

 

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Ordinary Heart Cells Become ‘Biological Pacemakers’ With Injection of Single Gene

 

Cedars-Sinai Heart Institute researchers have reprogrammed ordinary heart cells to become exact replicas of highly specialized pacemaker cells by injecting a single gene (Tbx18)-a major step forward in the decade-long search for a biological therapy to correct erratic and failing heartbeats.

Science Daily

The advance will be published in the Jan 8 issue of Nature Biotechnology and also will be available on the journal’s website.

“Although we and others have created primitive biological pacemakers before, this study is the first to show that a single gene can direct the conversion of heart muscle cells to genuine pacemaker cells. The new cells generated electrical impulses spontaneously and were indistinguishable from native pacemaker cells,” said Hee Cheol Cho, PhD., a Heart Institute research scientist.

Pacemaker cells generate electrical activity that spreads to other heart cells in an orderly pattern to create rhythmic muscle contractions. If these cells go awry, the heart pumps erratically at best; patients healthy enough to undergo surgery often look to an electronic pacemaker as the only option for survival.

The heartbeat originates in the sinoatrial node (SAN) of the heart’s right upper chamber, where pacemaker cells are clustered. Of the heart’s 10 billion cells, fewer than 10,000 are pacemaker cells, often referred to as SAN cells. Once reprogrammed by the Tbx18 gene, the newly created pacemaker cells — “induced SAN cells” or iSAN cells — had all key features of native pacemakers and maintained their SAN-like characteristics even after the effects of the Tbx18 gene had faded.

But the Cedars-Sinai researchers, employing a virus engineered to carry a single gene (Tbx18) that plays a key role in embryonic pacemaker cell development, directly reprogrammed heart muscle cells (cardiomyocytes) to specialized pacemaker cells. The new cells took on the distinctive features and function of native pacemaker cells, both in lab cell reprogramming and in guinea pig studies.

Previous efforts to generate new pacemaker cells resulted in heart muscle cells that could beat on their own. Still, the modified cells were closer to ordinary muscle cells than to pacemaker cells. Other approaches employed embryonic stem cells to derive pacemaker cells. But, the risk of contaminating cancerous cells is a persistent hurdle to realizing a therapeutic potential with the embryonic stem cell-based approach. The new work, with astonishing simplicity, creates pacemaker cells that closely resemble the native ones free from the risk of cancer.

For his work on biological pacemaker technology, Cho, the article’s last author, recently won the Louis N. and Arnold M. Katz Basic Research Prize, a young investigator award of the American Heart Association.

“This is the culmination of 10 years of work in our laboratory to build a biological pacemaker as an alternative to electronic pacing devices,” said Eduardo Marbán, MD, PhD, director of the Cedars-Sinai Heart Institute and Mark S. Siegel Family Professor, a pioneer in cardiac stem cell research. A clinical trial of Marbán’s stem cell therapy for heart attack patients recently found the experimental treatment helped damaged hearts regrow healthy muscle.

If subsequent research confirms and supports findings of the pacemaker cell studies, the researchers said they believe therapy might be administered by injecting Tbx18 into a patient’s heart or by creating pacemaker cells in the laboratory and transplanting them into the heart. But additional studies of safety and effectiveness must be conducted before human clinical trials could begin.

 

Story Source:

The above story is reprinted from materials provided by Cedars-Sinai Medical Center.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Journal Reference:

  1. Nidhi Kapoor, Wenbin Liang, Eduardo Marbán, Hee Cheol Cho. Direct conversion of quiescent cardiomyocytes to pacemaker cells by expression of Tbx18. Nature Biotechnology, 2012; DOI: 10.1038/nbt.2465

Politics, Legislation and Economy News

Politics / Legislation  :   Rule Of Law – Women’s Rights –  Reproductive Rights

 New Todd Akin Videos Reveal His  Dystopian Nightmare Vision of America

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Todd Akin is scared.
Photo by Whitney Curtis/Getty Images

After becoming a national scandal with his claims that “legitimate rape” cannot result in pregnancy, Rep. Todd Akin has been slowly regaining lost ground in the contest against incumbent Sen. Claire McCaskill for a Missouri Senate seat. Akin’s strategy has been to characterize the remark as a mere misspeaking that is not indicative of his larger character, and the strategy must be working, because at least one poll has him up by one percentage point.

But the left-wing PAC American Bridge 21st Century pointed me toward some C-SPAN videos that make it very difficult to take the “legitimate rape” thing as an anomaly.

One revealing glimpse into the Akin worldview: May 24, 2005, Akin’s speech denouncing stem cell research on the House floor. It’s a marvel of right-wing paranoia in which he fantasizes about what will happen if stem cell research continues—if it reaches what he calls “step three”—based on a story about harvesting organs from real humans that his daughter wrote:

My own daughter wrote a little story—I will read it—about step three. “I live with 40 others in a compound, supervised by cool, efficient orderlies. Instead of playing, I stood pondering a troubling dream from the night before. It was of a loving father, giving his child a name. I’ve always been just 5-25-61-B.”

Looks like someone’s been reading Never Let Me Go.

Here’s a clip of the speech, in which he also drops this gem of a quote characterizing women as climate control and food distribution systems: “Now an embryo may seem like some scientific or laboratory term, but in fact the embryo contains the unique information that defines a person. All you add is food and climate control, and some time, and the embryo becomes you or me.”

Daily Kos did some minor reporting on Akin’s weird ideas about abortion providers, but watching the full speech Akin gave on Jan. 22, 2008, reveals that his statement, “And yet we have terrorists in our own culture called abortionists,” is just a minor part of an elaborate fantasy about who abortion providers are, what they do, and why they do it.

Who wants to be at the very bottom of the food chain of the medical profession? And what sort of places do these bottom-of-the-food-chain doctors work in? Places that are really a pit. You find that along with the culture of death go all kinds of other law-breaking: not following good sanitary procedure, giving abortions to women who are not actually pregnant, cheating on taxes, all these kinds of things, misuse of anesthetics so that people die or almost die. All of these things are common practice, and all of that information is available for America.

It is clearly lost on Akin that the image he’s invoking—of dirty clinics that operate illegally and misuse pain medication—is the reality he’s trying to create. He wants to ban abortion, which is a surefire way to get a whole bunch of  illegal, underground clinics that aren’t held accountable to standard medical practice. If you want clean, safe abortion, you need it to be legal.

 

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