Cancer treatment in the future could have dramatically reduced side effects if new nanotechnology research proves useful. Heat-sensitive nanoparticles might be able to deliver drugs to a targeted location in the body—to a tumor, say—and release them on cue, a sought-after goal of biomedical research.
One research team has developed nanoparticle cages that can be stuffed with tiny amounts of drugs that are only released on demand. These “nanocages” are cubes of gold, with sides about 50-billionths of a meter long and holes at each corner. They are easily made, using silver particles as a mold, and then coated with strands of a smart polymer. The polymer strands are normally extended and bushy and cover the holes in the cube. But when heated the strands collapse, leaving the holes open and allowing the drug inside to escape [The New York Times]. The researchers say they can engineer the nanocages to stick to tumors.
Doctors could release the packaged drugs whenever they want, just by zapping the cages inside the patient’s body with near-infrared light. Near-infrared wavelengths are not greatly absorbed by body tissues, so light from a near-infrared laser could penetrate a couple of inches inside the body, but they are absorbed by gold [The New York Times]. Researchers could design the cages to fall apart at just a few degrees above normal body temperature, so they only spill their contents where the heat is applied; they could also alter the drug’s rate of release by adjusting the laser’s intensity. The technology, described in the journal Nature Materials, could help cut down on the side effects of today’s treatments which are often caused by toxic drugs coursing through the body.
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Image: Younan Xia, Washington University in St. Louis
The South Korean stem cell scientist who falsified cloning data was convicted today of embezzlement and illegally buying human eggs. The Seoul Central District Court sentenced Hwang Woo-suk to two years in prison for embezzling research funds and illegally buying human eggs. However, it suspended the penalty, allowing him to stay free if he breaks no laws for three years [Washington Post]. The judge stated Hwang has shown remorse and said that despite his fraudulent research the scientist has made other genuine advancements in cloning.
In May 2005, Hwang published a paper in the journal Science, saying his team had extracted material from cloned human embryos that identically matched the DNA of 11 patients. It was claimed such a technique could be the key to providing personalized cures for diseases such as cancer, Alzheimer’s and Parkinson’s [BBC News]. The paper garnered worldwide attention, along with heightened suspicion, because cloning embryonic stem cells was thought to be impossible due to the complexities of human cells. Proving the critics right, an investigation later concluded that the data were intentionally fabricated. Hwang later confessed to obtaining eggs for the research from his female colleagues, a clear violation of research ethics guidelines. However, he maintained that he did not fake his research, and is still working on animal cloning at a local institute.
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Image: iStockphoto
For all those patients who shudder at the thought of getting a colonoscopy and stubbornly refuse to make that appointment, there may soon be an alternative. Italian researchers have invented a “spider pill” that can be swallowed like a normal pill, but which later crawls through the intestines to check for signs of colon cancer. The researchers say the spider pill could be a great advance, because while the long and flexible endoscopes typically used in colonoscopies are very effective, many people balk at having a tube run through them.
The tiny bot contains a camera so doctors can monitor its progress through the digestive system (as demonstrated in this video). Once it hits the colon, doctors use a wireless link to command it to unfold its eight legs, and then order it to and fro so they can carefully check for polyps or tumors. Pills containing cameras already exist, but this is believed to be the first that can be controlled after it has been swallowed. Once the examination has finished, the spider pill exits the body naturally [Telegraph]. So far, the device has only been tested on pigs.
The researchers also invented a related device to survey the stomach, which contains more liquid than the intestines. That little bot uses propellers instead of legs to get around.
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Sigh. Less than three weeks after health officials convened a press conference in Thailand to announce a rare piece of good news in the hunt for an HIV vaccine, some scientists are asking whether the results were overstated.
The large clinical trial of the vaccine was a modest success, but it was plenty exciting for HIV vaccine researchers who have been waiting for years for any sign of progress. The U.S. Army and Thai researchers who collaborated on the trial found that the vaccine lowered the risk of infection by about 31% — a “modest benefit,” they said, but one that was statistically significant, suggesting the finding was not a fluke [The Wall Street Journal, blog]. But the press conference did not trumpet another analysis of the data, which included only those volunteers who carefully followed the experiment’s rules and got the full regimen of six shots at the right times. This second analysis showed a 26 percent rate of protection, and a much higher chance that the benefit was a fluke.
Some scientists say both analyses should have been revealed during the September announcement, and claim that the way the press conference was handled further undermines the research. “The press conference was not a scholarly, rigorously honest presentation,” said one leading HIV/AIDS investigator, who like others asked that his name not be used. “It doesn’t meet the standards that have been set for other trials, and it doesn’t fully present the borderline results. It’s wrong” [ScienceInsider].
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The movie Fight Club may have been on the right track when it suggested that the fat left over from liposuction procedures was too valuable to throw away–although the idea of making soap from forsaken flab is too gross to catch on. Instead, researchers have found a way to turn fat cells into stem cells, and say the process is much more efficient than the standard technique for stem cell production, which uses human skin cells.
Reprogramming human skin cells remains woefully inefficient; typically, it takes about a month for 1 in 10,000 fibroblast skin cells to give rise to induced pluripotent stem (iPS) cells. Such iPS cells can, like embryonic stem cells, develop into any cell type. So researchers have been on the lookout for tissue types that can more speedily and easily be turned pluripotent [Nature News].
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Using a bit of biotech wizardry that is becoming increasingly mundane, researchers took skin cells from patients with type 1 diabetes, and turned them first into induced pluripotent stem cells (iPS cells), the rough equivalent to the embryonic stem cells that can develop into any kind of tissue. Then researchers directed the cells to develop into insulin-producing beta cells, the type of cells that are destroyed by the immune system in type 1 diabetes.
Stem cell expert Meri Firpo notes that this technology could one day be used to create pancreatic beta cells for transplant from a person’s own skin cells. That way, there would be no need for immunosuppressive medications. However, because the current technique uses genetic manipulation to change the cell, Firpo said long-term safety issues would have to be addressed. Mouse cells that have been similarly manipulated have developed benign tumors, she said. So, using such cells for transplant is definitely not “a near-term thing,” she stressed [HealthDay News].
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A week-and-a-half after the first-ever human clinical embryonic stem cell trial was put on hold, Geron Corp. announced why: microscopic cysts that arose in laboratory animals but did not spread to other locations in the animals’ bodies.
In January, the FDA granted the company permission to begin using its stem cell treatment on patients with spinal cord injuries–but then the trial was delayed before the first patient could be enrolled. Although cysts developed occasionally during previous animal trials, they occurred more frequently in the more recent experiment. Geron was quick to point out, however, that the cysts were small and did not appear to be harmful in any way. In fact, the statement pointed out, cysts are not uncommon in victims of spinal cord injury, developing in the spinal cord scar tissue in up to 50% of patients [The Scientist]. In addition, the cysts did not develop into teratomas, a type of tumor that develops from pluripotent stem cells.
Geron said the company is working with the FDA to investigate the issue, and company officials are confident that the trial will soon be back on track. The FDA offered no comment regarding Geron’s announcement, saying they “neither confirm nor comment on clinical holds” [The Scientist].
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Image: iStockPhoto
Medical imaging tests such as CT scans are valuable diagnostic tools, but their increasing use in doctors’ offices and hospitals is providing a sizable dose of radiation for about 4 million Americans under the age of 65. About 400,000 of those Americans receive very high doses, more than the maximum annual exposure allowed for nuclear power plant employees or anyone else who works with radioactive material [The New York Times], according to a study published in The New England Journal of Medicine.
Researchers based their estimates on a study of almost 1 million people between the ages of 18 and 64 who they followed for almost three years, and found that nearly 70 percent of test subjects were subjected to at least one procedure that would have exposed them to radiation. Although the study didn’t examine whether this radiation could cause an increase in cancer rates, some experts believe it would probably result in tens of thousands of additional cancers…. Each individual patient is at relatively minor additional risk from the tests, [researcher and cardiologist Rita] Redberg said, but because they are given to so many people, the cumulative risk is significant [The New York Times].
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It may soon get easier to fix a broken hearts. Researchers have taken the next step towards heart patches that could one day help people recover from heart attacks.
Scientists have been experimenting with different ways to integrate new stem cells or cardiac cells with damaged heart tissue, but it’s a difficult task: the patches must be flexible enough to contract with the beating heart yet strong enough to hold up under the repetitive motion, and blood vessels must be coaxed through the new tissue to prevent the implanted cells from dying. In a new study published in Proceedings of the National Academy of Sciences researchers report that growing the patch in the belly of a rat brought better results when the patch was later moved to the rat’s heart.
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The next big leap in computing power may come from a surprising source: the genetic code. Researchers at IBM have found a way to use DNA strands as the scaffolding on which to place carbon nanotubes, creating tiny microchips that could eventually be more efficient and cheaper to produce than today’s silicon chips. To keep pace with Moore’s Law, which postulates that the number of transistors on an integrated circuit will double every two years, chip makers have to squeeze an increasing number of transistors onto every chip [Wired.com]. The new process offers an entirely different route to miniaturization.
Microchips are used in computers, cell phones and other electronic devices…. Right now, the tinier the chip, the more expensive the equipment. [An IBM spokesman] said that if the DNA origami process scales to production-level, manufacturers could trade hundreds of millions of dollars in complex tools for less than a million dollars of polymers, DNA solutions, and heating implements [Reuters].
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In a discovery that could be good news for denture users, scientists have grown teeth in adult mice using cells taken from a mouse embryo, according to a study published in Proceedings of the National Academy of Sciences. The method could pave the way towards the regeneration not just of teeth, but also human organs like livers and kidneys.
Scientists took tissue known as “tooth germ” from a mouse embryo and separated out two types of cells, which they recombined into a new bioengineered tooth germ. That tissue was then implanted into tooth sockets in the mouths of laboratory mice. After 37 days each clump of cells, which originally measured 500 micrometers, or 0.02 inches, had grown into a tooth visibly sprouting from the jawbones of the mice. The researchers also tracked gene expression in the engineered tooth “germ” with a fluorescent protein. This revealed that genes that were normally activated in tooth development were also active during growth of the engineered replacement [BBC News]. The implantation of the tooth “germ” was made possible by a method developed by the same team of scientists in 2007, which allowed them to grow immature teeth inside of the stomachs of embryonic mice.
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From the skin cells of humans and mice, scientists have successfully made brown fat, the kind that burns white fat by producing heat and is possessed in the greatest quantities by babies. The study, published in Nature, could potentially lead to a way to help overweight and obese people slim down.
Brown fat was once thought to be found only in children, but earlier this year researchers confirmed that adults also have a small amount of brown adipose tissue. In 2007, researchers discovered that a protein called PRDM16 made immature muscle cells turn into brown fat. In the new Nature study, the same team of scientists found that PRDM16, in combination with a second protein produced in muscle cells, is the master switch for brown fat cells and will also convert skin cells into brown fat, even though this is not the process nature intended. [Scientists] used this master switch to convert mouse skin cells to brown fat cells, which seem to work as expected when transplanted into normal mice [The New York Times]. The next step is to implant brown fat into obese mice to see if they lose weight; that will provide evidence that the discovery might be used outside of the lab.
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A startup biotechnology company unveiled its grand plans for a new energy source yesterday–although it didn’t share a few crucial details. The company, Joule Biotechnologies, says it has genetically engineered an organism that can efficiently produce unprecedented amounts of liquid fuel. However, chief executive Bill Sims will not reveal what that marvelous organism is. “If I tell you what the organism is, I’m inviting everyone else to take part in a transformational, evolutionary, game-changing technology” [Boston Globe], he says.
The company’s announcement comes soon after both ExxonMobil and Dow Chemical announced their investments in algae-derived biofuel production, and Joule’s technology has some similarities with those two projects. Like both those algae projects, Joule says it won’t be harvesting a plant and squeezing the oil out of it; instead the organism will secrete the fuel. But Sims says his organisms aren’t algae. In addition, Sims said the organisms do not need fresh water but can be grown in both brackish water or graywater, which is nonindustrial waste water from sources like baths and washing machines [Reuters].
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Injecting a certain protein into mice and rats stimulated their heart cells to multiply after a heart attack, improving cardiac function. The experiment’s results point to a possible method to regenerate damaged human heart tissue, according to a study published in the journal Cell.
The adult heart is remarkably static. Although research this year revealed that a tiny number of new heart muscle cells are created in adulthood, that cellular regeneration tapers off throughout life, so heart damage inflicted during a heart attack does not heal naturally. But scientists found that injecting a growth factor called neuregulin1 (NRG1) into mice and rats stimulated the animals’ heart cells to divide. After 12 weeks of daily injections, the animals’ hearts showed less hypertrophy, or enlargement, and improved function. For instance, the hearts had about a 10 percent increase in ejection fraction–the fraction of blood pumped out of the left ventricle with each beat. The treatment “didn’t make the damage go away completely, … but it did make the heart work significantly better” [Technology Review], says lead researcher Bernhard Kühn.
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From reprogrammed skin cells, scientists have made live mice.
The accomplishment is the latest step forward in the exciting new field of reprogrammed cells, which may offer an alternative to embryonic stem cells…. [It's] the most definitive evidence yet that the technique could help sidestep many of the explosive ethical issues engulfing the controversial field [Washington Post]. Two new studies describe the process, and one team of researchers reports producing 27 live mice. While there were abnormalities and unusual deaths with some of the first generation of mice, [the] team produced enough normal mice this way to create hundreds of second and third generation mice [AP].
It was only three years ago that Japanese stem cell researchers found a way to reprogram ordinary skin cells to behave like embryonic stem cells, which are thought to hold vast potential for medical research because they can develop into any kind of body tissue–from heart cells to toenail cells. But researchers didn’t know if the reprogrammed adult cells, known as induced pluripotent stem cells or iPS cells, were capable of differentiating into every type of tissue, the way embryonic stem cells do.
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