Scientists have identified the “master” stem cell that gives rise to the three types of heart cells, possibly opening the door for new methods of pharmaceutical research and heart therapies, such as growing a patch to repair cardiac tissue damaged by heart disease, according to a study published in Nature.
The research illuminates a crucial facet of how heart tissue develops and shows why past studies to repair heart tissue with stem cells had poor results: the cells used were not the heart tissue progenitors that lead author Kenneth Chien and his team identified. The researchers then purified the cells, cloned them and tracked their journey from single stem cell to the three major lineages of heart cells — smooth muscle, cardiomyocyte [or striated] muscle and endothelial cells [U.S. News and World Report], which line the inside of the heart. For years, scientists have studied the development of the heart in animals like the zebra fish, but this finding will allow researchers to closely examine the genesis of human cardiac tissue in unprecedented detail.
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Although ethical debates about the use of embryonic stem cells continue to rage, stem cell technology is beginning to make its way into the medical marketplace. Yesterday, General Electric division GE Healthcare announced that it’s teaming up with the biotechnology company Geron in a venture that will use embryonic stem cells to develop products that could give drug developers an early warning of whether new medicines are toxic [Reuters].
The agreement marks the first time that a company of GE’s stature and size has announced a business venture involving the controversial field of embryonic stem cells. That could reflect a more tolerant climate for the technology in the wake of the Obama administration’s recent relaxation of restrictions on embryonic stem-cell research [The Wall Street Journal]. Supporters of embryonic stem cell research say the work will lead to a host of treatments for cancer and other diseases, while opponents believe that the destruction of any human embryo is unacceptable.
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Chemotherapy destroys cancer cells, but it also kills healthy cells. In addition, cancer cells left behind after treatment can develop resistance to therapy, rendering follow-up treatment ineffective. But a new type of cancer treatment that uses cellular “Trojan horses” to slip into cancer cells could remedy that. In a study published in Nature Biotechnology, Australian researchers describe a method that has successfully treated aggressive and resistant tumors in mice and dogs.
The technique uses a rising technology known as RNA interference, or RNAi, which was the subject of research for the 2006 Nobel Prize in medicine recipients. This technology prevents the cell from manufacturing proteins by muting the genes responsible for their production, and relies on “mini-cells” to silence these genes. In the new study, these mini-cells were produced by bacteria and then coated with antibodies the cancer cells recognized, which allowed the mini-cells to target and slip inside of cancer cells like a Trojan horse.
The researchers use a two-step attack against the cancer cells. The first wave of mini-cells releases molecules that switch off the production of proteins that make the cancer cell resistant to chemotherapy. A second wave of EDV [mini] cells is then accepted by the cancer cell and releases chemotherapy drugs, killing the cancer cell. “The beauty is that our EDVs operate like ‘Trojan Horses’ They arrive at the gates of the affected cells and are always allowed in” [Reuters], says study coauthor Jennifer MacDiarmid.
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It was only a few years ago that scientists figured out how to reprogram adult cells to make them act like multipurpose stem cells, but the next discoveries are coming fast and furious. Researchers had previously transformed human skin cells into so-called induced pluripotent stem (iPS) cells that can grow into any type of tissue; now, a new study reports that the same feat has been accomplished with pig cells. The achievement raises the possibility that genetically engineered pigs could be reared as organ donors, researchers say.
The created iPS cells could be genetically altered, and then cloned to produce pigs with certain traits. By adding or deleting certain genes, for example, researchers could produce pigs whose organs can be transplanted into patients without them being recognised and rejected. Efforts to do such xenotransplants have already been under way for at least a decade, but iPS cells are easier to genetically engineer and grow in the lab than pig embryos, opening up new possibilities for xenotransplantation [New Scientist]. Pigs are considered potential organ donors because their organs are already similar to those of humans in size and function.
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Researchers have found a new way to reprogram human skin cells to act like multipurpose stem cells, and say their safe technique produces stem cells that are ready for medical use. If the researchers are right, clinical trials on the induced pluripotent stem (iPS) cells, which can turn into virtually any cell type and potentially be used to treat disorders ranging from spinal cord injury to diabetes, could start within two years [Nature News].
Many experts say that reprogrammed skin cells have several advantages over embryonic stem cells, for reasons both societal and medical. Using adult cells dodges the ethical controversy involved in taking cells from embryos, and it also raises the possibility that patients’ own cells could be used in their medical treatment, negating the chance that the cells would be rejected by their bodies. But reprogramming cells is still a scientific frontier, and researchers have struggled to find safe ways to accomplish the feat.
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In a masterful work of “DNA origami,” researchers have created a nanoscale DNA “box” which can be opened with DNA “keys”. One day, such structures could be filled with drugs, injected into the blood, and then unlocked when and where the drugs are required [New Scientist]. Researchers say the boxes could also be used as minuscule environmental sensors that open or close in response to a stimulus, or as the logic gates of a DNA-based computer.
To accomplish this feat, described in a paper in Nature, researchers exploited the fact that complementary DNA bases–the fundamental building blocks of DNA’s double helix–attach to each other. To design the box, the researchers developed a computer program to generate a continuous single-stranded DNA sequence that, along with smaller DNA fragments that act as staples, would self-assemble into the desired shape. The sequence was devised with many complementary regions so that it would automatically fold into six roughly square accordion-like sheets–the sides of the box–based on DNA’s natural tendency to pair into double strands. The DNA staples, also driven by the pairing of complementary sequences, stitched the sheets’ edges together to form a hollow cube with a hinged lid [Technology Review]. The final product was a box that measured 42 by 36 by 36 nanometers, and had a cavity big enough to hold enzymes or virus particles.
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A new genetically modified (GM) corn that produces beta carotene and precursors of vitamin C and folic acid is the first crop to be engineered to make more than one vitamin. Says lead researcher Paul Christou: “The major message of the paper is that it’s possible to engineer crops with multiple nutrients…. If you look at other nutritionally enhanced GM crops, up until now people have only been able to increase levels of one nutrient or vitamin” [Wired]. But anti-GM campaigners have not been won over by the scientific feat, even though the research behind it was not funded by agricultural corporations.
The researchers inserted five genes from other organisms—including rice and Escherichia coli—into a popular South African white corn variety called M37W that Christou said is “completely devoid of vitamins” [Los Angeles Times]. They then bombarded the corn embryos with metal particles coated with chunks of DNA that, if taken up by the embryo, would alter its internal biochemical processes to make it produce the vitamins [BBC]. Follow-up analysis of plants grown from the modified seeds showed not only their successful manipulation, but that the changes lasted several generations. The changes amounted to a 169-fold increase in beta carotene, a precursor of vitamin A. The corn also has six times the normal amount of vitamin C and double the usual level of folate [Los Angeles Times].
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A high-powered consortium in the United Kingdom has declared a push to create synthetic blood from embryonic stem cells over the next decade. “In principle, we could provide an unlimited supply of blood in this way” [BBC News], says researcher Marc Turner. Synthetic blood would be guaranteed to be free of viruses like HIV, and could also prevent shortages at blood banks, emergency rooms, and battlefield operations.
While the American biotech company Advanced Cell Technology (ACT) announced last August that they had developed a technique of creating blood from embryonic stem cells, the new UK effort has more significant institutional backing. The multimillion-pound deal involving NHS [National Health Service] Blood and Transplant, the Scottish National Blood Transfusion Service and the Wellcome Trust, the world’s biggest medical research charity, means Britain will take centre stage in the global race to develop blood made from embryonic stem cells [The Independent].
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Researchers have tweaked HIV virus to create a strain that can infect monkeys, and say the development will allow better testing of vaccines and AIDS drugs. Until now, AIDS researchers used monkeys infected with simian immunodeficiency virus, or SIV. The virus is similar to ours, but it’s far from a perfect research tool…. Though SIV and HIV wreak similar havoc on their hosts’ immune systems, drugs affect them differently. While that makes SIV useful for studying how the disease progresses, it’s less useful for studying potential treatments [Wired News].
The new strain of HIV was developed by altering a single gene in the human version to allow it to infect a type of monkey called a pig-tailed macaque [Reuters]. The researchers replaced one HIV gene with the SIV version of the gene, which blocks virus-killing proteins made by the monkey and allows the infection to take hold. Even this altered virus doesn’t make the monkeys very sick, but while animal lovers may see that as a benefit, researchers see it as the final hurdle to overcome.
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A new study shows that teenage boy developed cancerous tumors because of the stem cell therapy he received years ago for a rare genetic condition. The boy, now 17, suffered from ataxia telangiectasia, or AT, a neurodegenerative disease that interferes with the part of the brain that controls movement and speech. AT patients do not usually live past their teens or 20s, and the Israeli boy, whose identity was not publicly revealed, was taken to Russia for experimental treatment. The first neural stem cells, taken from fetuses, were first injected into his brain and spinal cord when he was nine, and he received further injections at ages 10 and 12.
His condition deteriorated and he was using a wheelchair by age 13, when he also began to complain of headaches. Tests showed two growths, one pushing on his brain stem and the other on his spinal cord. The tumors were removed in 2006 and his health has since remained stable. But scientists at Tel Aviv University who wanted to determine the origin of the cancer have been in the lab ever since, and their findings have just been published in PLoS Medicine. The team found that the tumor could not have arisen from the boy, because he [has two disease-causing versions of the gene] that causes AT, while the DNA from the tumor cells carried only the normal version [The Scientist].
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In an important step towards the creation of artificial life, scientists in Florida announced this week they have created a synthetic form of DNA that, with a catalyst, can replicate itself. The breakthrough moves biochemist Steven A. Benner closer to achieving what he calls “Darwinian evolution in a test tube” [Seed Magazine].
Benner’s artificial genetic system comprises four nucleotides—building blocks of DNA—seen in humans, plus eight extra nucleotides he created by altering the human versions. He got the synthetic DNA to reproduce using the polymerase chain reaction, a common tool of molecular biology whereby an enzyme triggers the duplication of genetic material; natural DNA, in contrast, can replicate on its own. Once the synthetic form can self-replicate, said Benner, “then it’s artificial life” [LiveScience].
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The future, according to author and technological soothsayer Ray Kurzweil, is going to be awesome. In his books, he maps out a future for humanity in which we live forever, supported by a fleet of cleverer-than-human artificial intelligences who solve such trivial problems as hunger and disease, while simultaneously creating ever more intelligent computer minds, racing technological progress forward according to his Law of Accelerated Returns [Telegraph]. Now, Kurzweil is opening a new school, Singularity University, that will gather smart people together and encourage them to bring that future to pass.
Kurzweil dreamed up the school with Peter Diamandis, CEO of the X Prize Foundation, and got backing from Google and NASA; it will be housed on the NASA Ames base in California. The university takes its name from Kurzweil’s recent book, The Singularity Is Near, in which he argues that exponential advances in technology will shortly transform human life beyond all recognition…. This is Kurzweil’s own take on the widespread science-fiction use of the term “singularity” to refer to the day when artificial “intelligence” and/or processing power surpasses that of the human race’s collective brains. Sci-fi writer Vernor Vinge probably did most to hijack the word “singularity” from its use in physics to describe the breakdown of normal principles near a black hole [The Register].
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An extinct mountain goat that was once common in the Pyrenees briefly became the first animal to be brought back from extinction, as researchers used frozen DNA to produce a clone. But the newborn kid died within minutes of birth due to breathing difficulties, signaling that the Jurassic Park dream of resurrecting extinct species is still some way off.
The Pyrenean ibex, or bucardo, is a subspecies of the Spanish ibex that is believed to have died out completely in 2000. Before the death of the last known individual (a 13-year-old female known as Celia), biologists captured her and took cells from her skin and ears, which were frozen in liquid nitrogen. An earlier cloning attempt using the skin cells failed during gestation. But the latest attempt involved the creation of 439 ibex-goat hybrid cloned embryos made by inserting the cell nuclei of the ibex’s skin cells into the egg cells of domestic goats which had their own cell nuclei removed. Of these cloned embryos, 57 were transferred into surrogate mothers and seven resulted in pregnancies, but only one goat gave birth and the newborn clone died after seven minutes as a result of lung deformities [The Independent].
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Fingerprints are for more than a good grip; they also allow fingers to feel fine textures, according to a new study. As fingers move across a surface, the intricate geography of the finger tips, known as epidermal ridges, help select and amplify just the right vibrations to convey information from the skin to the brain. Neuroscientist Ellen Lumkin compares the ridges on fingers to the cochlea in the ear. “Like the cochlea is a frequency analyzer for sounds, the fingertips are frequency analyzers for fingers,” says Lumpkin [Science News] Fingerprints help filter out the tactile equivalent of white noise.
When a finger sweeps over a finely textured surface, such as a cotton sleeve or a wooden coffee table, the interaction sends a large range of vibrations into the skin. Specialized sensors called Pacinian fibers, the tips of nerve fibers, detect only a select few of the vibrations — those right around 250 hertz — before sending the signal to the brain, where the touch sensation is processed [Science News]. But since Pacinian fibers are located relatively deep—about 2 millimeters—under the skin, researchers guessed that fingerprints help magnify the vibrations.
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A Florida couple has just received a genetic copy of their beloved and deceased golden Labrador Sir Lancelot, naming the three-month-old puppy Lancelot Encore. The couple paid $155,000 for one of the first commercially cloned dogs in the world, and say the money was well spent. “He was a wonderful dog,” said Nina Otto, 66. “Money wasn’t an object. We just wanted our wonderful, loving dog back” [ABC News]. The project was masterminded by the California biotech company BioArts.
Lancelot Encore joins a handful of other dogs cloned either commercially or as a proof of concept, and the latest success seems to indicate that researchers have thoroughly overcome the scientific barriers to cloning man’s best friend. Canines are considered one of the more difficult mammals to clone because of their reproductive cycle that includes difficult-to-predict ovulations [Reuters]. Now the fate of the fledging pet cloning industry is largely dependent on whether dog lovers think that clones are worth the high price tag. However, just yesterday another cloning company announced a new technique that could reduce the cost of dog cloning to about $50,000 within three years.
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