Wednesday, May 7, 2008
Chew This Over: Mechanical Mouth Unveiled in France
French researchers have developed an artificial mechanical mouth, which can supposedly munch up food very similarly to how a human mouth does it. The device is intended to be used for testing various foods with regards to quality, and to also understand how flavors are influenced by the physical composition of the food.
The munching device mimics the first steps of digestion - chewing, saliva release and food breakdown. About five times the size of a human mouth inside, the steel container is kept at a steady 37°C by an electrical element. Its internal surfaces are coated with a chemically resistant plastic used for medical implants.The ceiling and floor of the cylindrical chamber are attached to variable speed motors. Food is placed on the floor which is able to revolve, while the ceiling coated spiky "teeth" moves up and down like a plunger (see image, right).
The compression and rotation simulate the mechanical forces food undergoes in the mouth. The process is made more realistic by the addition of enzyme-containing artificial saliva through a pipe in the base of the chamber.
Helium supplied through another inlet flows through the "mouth" to reproduce the effect of breathing and carry volatile compounds away for analysis.
More from the New Scientist...
Full article in the Journal of Agricultural and Food Chemistry (DOI: 10.1021/jf073145z)
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Wednesday, May 7, 2008
The SolarAid Revisited
Two years ago we reported on the SolarAid, a low cost solar-powered hearing aid intended for the hearing-impaired in developing countries. A recent article in Newsweek looks at the success of the device and gives a little insight into the mind behind it, Howard Weinstein:
Weinstein knew what he had to do: change the business model. Drawing on his years in the corporate bunker, he started working the phones, chatting up financiers, consulting with electronics wizards and haggling with manufacturers. He landed a small grant from the U.S. government-run African Development Foundation and, with help from some dedicated electronics geeks and industry execs willing to forgo their usual profits, came up with something new: a cheap hearing aid powered by rechargeable solar batteries. It looked ordinary enough—just a cashew-shaped piece of plastic to tuck behind the ear—but it cost less than $100, a fifth the price of the cheapest retail model. Rechargeable batteries, $1 apiece, last two to three years. None of this was much use without a reliable power source, so he also built a pocket-size recharger that can either plug into a wall outlet or use its own built-in solar panel.Weinstein has tapped into another source of underused energy: deaf people. "Because mastering sign language takes acute hand-eye coordination, deaf people are well suited to the fine soldering and microelectronics that go into making hearing aids," he says. Today the once empty room in the African semi desert has become the hub of a thriving nonprofit business. Some 20,000 people in 30 countries are using SolarAid brand hearing aids, chargers and batteries. With funding from the Ashoka Foundation and the Oregon-based Lemelson Foundation, Weinstein is working with engineers from the University of São Paulo on a second-generation, digital hearing aid. He sees Brazil as a beachhead for all of Latin America; he plans to set up another nonprofit company in Jordan to reach the entire Middle East. Then he'll take on China and India. All told, he hopes to employ 1,000 deaf people over the next three to five years.
Read the whole article here...
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Tuesday, May 6, 2008
Study Shows Incubators Change Babies' Heartbeat
Carlo Bellieni, et. al. from the University of Siena, Italy published a study in the latest Archives of Disease in Childhood that apparently shows changes in heart rate variability (HRV) in a small group of newborns in a neonatal ICU. The authors believe that electromagnetic fields in incubators, as documented in changes in HRV throughout three 5-minute periods (with incubator motor on, off, and on again), have some kind of effect on the neonatal autonomous nervous system.
To learn more about the study, read this editorial in Nature...
Abstract: Electromagnetic fields produced by incubators influence heart rate variability in newborns Arch. Dis. Child. Fetal Neonatal Ed..2008; 0: adc.2007.132738v2
Image credit: keaggy.com @ Flickr: My Blue Girl...
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Medical Pixie Dust: Is It Finally Here?
An Ohio man recently chopped off a part of his finger while playing with a model plane rotor. Luckily for Mr Lee Spievak, his brother Alan is a researcher within the field of regenerative medicine, and had access to Dr Stephen Badylak's "pixie dust", developed at the University of Pittsburgh.
The process [Dr Stephen Badylak] has been pioneering over the last few years involves scraping the cells from the lining of a pig's bladder. The remaining tissue is then placed into acid, "cleaned" of all cells, and dried out.It can be turned into sheets, or a powder. It looks like a simple process, but of course the science is complex.
"There are all sorts of signals in the body," explains Dr Badylak. "We have got signals that are good for forming scar, and others that are good for regenerating tissues. "One way to think about these matrices is that we have taken out many of the stimuli for scar tissue formation and left those signals that were always there anyway for constructive remodelling."
In other words when the extra cellular matrix is put on a wound, scientists believe it stimulates cells in the tissue to grow rather than scar.If they can perfect the technique, it might mean one day they could repair not just a severed finger, but severely burnt skin, or even damaged organs.
More from the BBC with video of the patient and Dr Badylak explaining the production process...
UPDATE: A Note on Medical Pixie Dust
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Monday, May 5, 2008
Cellular Quality Control via Organelle Autophagy
A group from the Baylor College of Medicine is reporting in the upcoming issue of Nature on discovering a novel mechanism responsible for the clearance of mitochondria in red blood cells. According to the researchers, such process is not only responsible for maintaining health and stability of red blood cells, but could also be involved in the quality assurance in other cells throughout the body. The discovery could have some major clinical implications:
A process of self-digestion called autophagy prompts the maturation of red blood cells. Without a protein called Nix, the cells would not effectively rid themselves of organelles called mitochondria and consequently become short-lived, leading to anemia, said researchers at Baylor College of Medicine in Houston in a report that appears online today in the journal Nature."It's changed our thinking on autophagy," said Dr. Jin Wang, assistant professor of immunology at BCM and senior author of the report. During autophagy, the cell forms an envelope or vesicle around components of the cell that need to be degraded and removed. The vesicle then fuses with a cellular component called a lysosome that degrades its contents. The inclusion of components in the cell by autophagy vesicles was generally considered to be nonspecific.
"This is not a random process," said Wang. "Nix is instructing the cell to get rid of these mitochondria."
Nix accomplishes this task by disrupting the mitochondrial membrane potential (represented by difference in voltage across the inner membrane of the mitochondria. The interior is negative and the outside positive. The difference generates a force that drives the synthesis of ATP, the cell's energy molecule).
"We think the finding is not limited to the clearance of mitochondria in red blood cells," said Wang. "When other cells get old or stressed, their organelles may become damaged and need to be cleared by autophagy for quality control. If the cells lack such quality controls, they might have problems that result in aging, cancer and neurodegenerative diseases."
"It helps get rid of old or damaged mitochondria," he said. "It is a way to keep the cell functioning without going through programmed cell death (apoptosis)."
"Such specific regulation of autophagy may also be important for cell types in the muscle, brain and pancreas," said Dr. Min Chen, assistant professor of immunology at BCM and a corresponding author of this work. "The next step is to identify proteins interacting with Nix for mitochondrial quality control by autophagy". Other factors may also regulate this process in addition to Nix, said Hector Sandoval, a BCM graduate student who is the first author of this paper.
Press release: Protein 'nixes' mitochrondria...
Image credit: Wellcome images: Red blood cells clearly showing their biconcave disc shape. Scanning electron micrograph 2006
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MIT Tech Review Talks to Systems Biologist Leroy Hood
Biotech pioneer Dr. Leroy Hood, who is also president and co-founder of the Institute for Systems Biology in Seattle, recently gave an interview to the MIT Tech Review.
A snippet:
TR: You've said that solutions to biological complexity will be applied to complex problems in other fields. Can you explain what you mean by this?LH: Evolution has had four billion years to figure out really clever solutions for new materials, new chemistries, new types of molecular machines, even new approaches to computing. I think by studying living organisms and deducing the mechanisms that underlie these evolutionarily sculpted solutions to complexity, those solutions can be applied to other fields. A classic example is materials science. The spectrum of different materials that organisms have evolved to make is enormous.
TR: For the past several years, researchers at your institute have talked about a diagnostic "nanochip" that would detect markers of disease from all over the body. Can you update me on that project?
LH: What we're interested in doing is developing strategies that will let us identify proteins in the blood that will permit us to interrogate the state of individual organs: the liver, the heart, the muscle--whatever you'd like to look at.
The basic idea is that the organ-specific proteins from, say, the liver will reflect the operation of the networks in the liver. So they'll be at one set of concentrations for normal liver, and a different set of concentrations for a liver that has cancer or hepatitis or cirrhosis and other diseases. These blood fingerprints, then, are not assays for a disease; they're assays for all disease. We've looked at two organ systems: the brain and the liver. We've certainly verified in general ways these principles.
We'd like to be able to identify fiftyish organ-specific blood proteins from each of the organs, and then be able to measure them so we could have an organ-wide assay. We'd like to give you a very broad-spectrum screen of all the different major organs in disease. The challenge is to be able to do the measurements in the blood, because that's the only organ that's readily accessible; that's the only organ that bathes all other organs; and it's an organ whose fluid properties make it easily manipulable for measurement and so forth.
More from Dr. Leroy Hood profile page at the Institute for Systems Biology...
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Cheaper Methods for Remote Medical Imaging
Researchers from the University of California at Berkeley and Hebrew University of Jerusalem developed a computational technique that could bring diagnostic medical imaging to poorer and more remote communities. The method is based on technology that quickly transmits medical images from devices by moving the image processing tasks, which typically require a great deal of calculations, to a remote server.
Most medical imaging devices, said Rubinsky, consist of three essential components: the data acquisition hardware that is connected to the patient, the image processing software and a monitor to display the image. When these components are combined into one unit, machine parts often become redundant, substantially increasing the cost of the device, he said.Rubinsky and his team came up with the novel idea of physically separating these components so that the most complicated element - the processing software used to reconstruct the raw data into a meaningful image - can reside at an offsite central location, presumably in a large center where resources are available for its operation and maintenance. This central location would be used to service multiple remote sites where far simpler machines collect the raw data from the patients.
That's where the cell phone comes in. The phone, hooked up to the data acquisition device, would transmit the raw data to the central server where the information would be used to create an image. The server would then relay the image back to the cell phone, where it can be viewed on the cell phone's screen.
"This design significantly lowers the cost of medical imaging because the apparatus at the patient site is greatly simplified, and there is no need for personnel highly trained in imaging processing," said Ivorra, the post-doctoral researcher. "The data acquisition device can be made with off-the-shelf parts that somebody with basic technical training can operate. As for cell phones, you could be out in the middle of a remote village and still have cell phone access. They're so prevalent because so little infrastructure is required to maintain wireless networks."
More from Roland Piquepaille at ZDNet...
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Wednesday, April 30, 2008
Shiny, Happy, Medilicious
A research duo from Dartmouth and Dana-Farber Cancer Institute has discovered that cancer medications have names that are associated with "lightness, smallness, and fastness". Moreover, Gregory Abel, a Dartmouth linguist, goes further to say that there might be a "subtle effect on both the patient taking the medicine and the doctor prescribing it."
The study, titled “Chemotherapy as language: Sound symbolism in cancer medication names,” was published online on Feb. 4, 2008, in the journal Social Science and Medicine. Glinert collaborated with Gregory Abel, a co-author on the study who is with the Center for Outcomes and Policy Research at Dana-Farber Cancer Institute and a member of the Dartmouth Class of 1991.In their paper, Abel and Glinert explain that the use of language and narrative and its significance in caring for patients has been studied. Their examination adds a linguistic layer to the scholarship, deepening the understanding of how the sounds in a medication’s name might have an underlying symbolism. The team looked at the sound symbolism of 60 frequently used cancer medications. Sound symbolism is the phenomenon where tiny bits of sounds have intrinsic connotations.
“Medications are a bridge between patients and health care providers, and our findings might point to some symbolic and subtle, yet powerful, associations with the names of those medications,” says Glinert, who is also affiliated with Dartmouth’s program in linguistics and cognitive science. “The fact that sounds that elicit lightness, smallness, and fastness were found in the names of cancer medicines might suggest that it helps patients handle the therapy.”
Press release: Researcher finds symbolic overtones in the names of cancer medicines
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Tuesday, April 29, 2008
Absinthe Is Just Booze
We have some sad news for all the absinthe aficionados: you are simply alcohol lovers. The whole idea of supposed absinthe exceptionalism is up in flames, so to speak.
The American Chemical Society explains the results of this latest study:
A high alcohol content, rather than thujone, the compound widely believed responsible for absinthe's effects. Although consumed diluted with water, absinthe contained about 70 percent alcohol, giving it a 140-proof wallop. Most gin, vodka, and whiskey are 80 to 100-proof and contain 40-50 percent alcohol or ethanol.The study is scheduled for the May 14, 2008 issue of the American Chemical Society's bi-weekly Journal of Agricultural and Food Chemistry, where the full text of the article can be downloaded now without charge.
Absinthe took on legendary status in late 19th-Century Paris among bohemian artists and writers. They believed it expanded consciousness with psychedelic effects and called it 'the Green Fairy' and 'the Green Muse.' The drink's popularity spread through Europe and to the United States. However, illness and violent episodes among drinkers gave absinthe the reputation as a dangerous drug, and it was banned in Europe and elsewhere.
In the new study, Dirk W. Lachenmeier and colleagues point out that scientists know very little about the composition of the original absinthe produced in France before that country banned the drink in 1915. Only a single study had analyzed one sample of preban absinthe. The researchers analyzed 13 samples of preban absinthe from sealed bottles-"the first time that such a wide ranging analysis of absinthe from the preban era has been attempted," they say.
The analysis included thujone, widely regarded as the 'active' ingredient in absinthe. "It is certainly at the root of absinthe's reputation as being more drug than drink," according to Lachenmeier. Thujone was blamed for 'absinthe madness' and 'absinthism,' a collection of symptoms including hallucinations, facial contractions, numbness, and dementia.
However, the study found relatively small concentrations of thujone, amounts less than previously estimated and not sufficient to explain absinthism. Thujone levels in preban absinthe actually were about the same as those in modern absinthe, produced since 1988, when the European Union (EU) lifted its ban on absinthe production. Laboratory tests found no other compound that could explain absinthe's effects. "All things considered, nothing besides ethanol was found in the absinthes that was able to explain the syndrome of absinthism," according to Lachenmeier.
He says that scientific data cannot explain preban absinthe's reputation as a psychedelic substance. Recent historical research on absinthism concluded that the condition probably was alcoholism, Lachenmeier indicates.
Press release: Absinthe uncorked: The 'Green Fairy' was boozy -- but not psychedelic...
Image credit: absinthe still life by Agenda893 on Flickr
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How Roses Handle Water
A team of chemists from Tsinghua University in Beijing, China figured out why tiny water droplets seem to get stuck to petals of red roses. Not unexpectantly, the mechanism, known as the Cassie impregnating wetting state, is a result of nanostructures ("hierarchical micropapillae" and "nanofolds") on the surface of petals. What does it all have to do with medicine? Well, the usual: possible future medical materials, or other technologies.
Nature explains:
The beading of water droplets on natural materials is not a rare thing. But on many flowers and leaves the droplets slide off with the slightest tremble, taking dust and small insects off with them. The effect is known by biologists as 'self cleaning' and has been well studied by researchers keen to make better water-repellent materials.The water slides off because the surfaces are very rough and spiky at the microscopic scale, and the tips of the spikes are covered in wax. The water molecules therefore come into contact with only a tiny fraction of the surface, and then only to water-repelling wax.
Lin Feng and her colleagues at Tsinghua University in Beijing found that although rose petals are coated with similar projections, they have wide, gentle-sloping troughs between the spikes, and no wax. The spikes keep the dew drops in a spherical shape, but the water 'leaks' into the troughs between spike-covered bumps, giving a bit of 'stick' and stopping a small droplet from rolling around (see diagram). Feng and colleagues report this structure in the journal Langmuir.
Once the team realized what the rose petals were doing to hold water, they were curious whether they could replicate the effect. They put some polyvinyl alcohol onto rose petals and allowed it to set, then peeled off a thin plastic cast of the petal surface. This film, the researchers found, had the same properties as the rose petal: the film could hold droplets of between 3-5 microlitres even when held upside down...
For a rose, this stickiness might come in handy as reflective water drops that glisten in the Sun might attract pollinating insects. In the lab, such materials might be useful for 'lab on a chip' devices that need to hold and shunt around tiny quantities of liquid without leaking or being contaminated by nearby materials.
Read: Raindrops on roses...
Abstract: Petal Effect: A Superhydrophobic State with High Adhesive Force Langmuir, 24 (8), 4114 -4119, 2008.
Image credit: . . . captured in a rose by fmarq on Flickr
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Salvia Divinorum's Mysteries Being Studied
Salvia divinorum, an unusual psychoactive sage described by a Brookhaven National Lab scientist as "probably one of the most potent hallucinogens known," is currently on brisk sale throughout lower Manhattan, as well as most of the rest of the country where it is currently legal. The plant has gained some popularity over the years, and scientists are trying to learn more about its interaction with the brain.
Hooker [Jacob Hooker, chemist at Brookhaven and lead author of the study --ed.] and fellow researchers used positron emission tomography, or PET scanning, to watch the distribution of salvinorin A in the brains of anesthetized primates. In this technique, the scientists administer a radioactively labeled form of salvinorin A (at concentrations far below pharmacologically active doses) and use the PET scanner to track its site-specific concentrations in various brain regions.Within 40 seconds of administration, the researchers found a peak concentration of salvinorin A in the brain - nearly 10 times faster than the rate at which cocaine enters the brain. About 16 minutes later, the drug was essentially gone. This pattern parallels the effects described by human users, who experience an almost immediate high that starts fading away within 5 to 10 minutes.
High concentrations of the drug were localized to the cerebellum and visual cortex, which are parts of the brain responsible for motor function and vision, respectively. Based on their results and published data from human use, the scientists estimate that just 10 micrograms of salvia in the brain is needed to cause psychoactive effects in humans.
Salvia doesn't cause the typical euphoric state associated with other hallucinogens like LSD, Hooker said. The drug targets a receptor that is known to modulate pain and could be important for therapies as far reaching as mood disorders.
"Most people don't find this class of drugs very pleasurable," Hooker said. "So perhaps the main draw or reason for its appeal relates to the rapid onset and short duration of its effects, which are incredibly unique. The kinetics are often as important as the abused drug itself."
The Brookhaven team plans to conduct further studies related to salvia's abuse potential. The scientists also hope to develop radioactive tracers that can better probe the brain receptors to which salvia binds. Such studies could possibly lead to therapies for chronic pain and mood disorders.
Press release: Brookhaven Scientists Explore Brain's Reaction to Potent Hallucinogen
PET images (color) of [11C]-salvinorin A in the baboon brain overlaid on MRI template (black and white) summed from 3-7 minutes post-injection. High concentrations (red) were observed in the cerebellum and activity was seen throughout cortical and subcortical regions. The maximum concentration of [11C]-salvinorin A in the brain occurs in 40 seconds and clears with a half-life of only 8 minutes, matching the pharmacological duration of action.
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Monday, April 28, 2008
The Human Speechome Project
One might think that Deb Roy is a paranoid individual, seeing how he installed 11 video cameras and 14 microphones throughout his house to monitor every movement and word spoken by anyone inside. Yet, what Dr. Roy of MIT Media Lab is attempting to learn from this seeming madness is how children learn to speak over time, and his newborn son is the first subject.
“My ultimate goal is to understand how language works,” Roy explains. That’s a tall order, and the logical place to start, he maintains, is with children. Decades of inquiry involving video and audio recordings of children interacting with caregivers and psychologists in institutional “speech labs” have laid a foundation to begin answering questions about how children develop language skills. The day-in/day-out interactions between children and adults, Roy points out, are key to the way children grasp language. “But for all of the interest in how children learn language, there’s no comprehensive data of even a single child’s development,” Roy says. “Most researchers rely on speech recordings that cover less than 1.5 percent of a child’s complete linguistic experience.”
We wonder whether the child's name is Truman by any chance.
More from Apple science profiles...
(hat tip: Engadget)
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Friday, April 25, 2008
Possible Link Between Viruses and Lung Cancer Shown
Researchers from University of Louisville, Kentucky and Soroka Medical Center in Beer Sheva, Israel have presented two papers at the 1st European Lung Cancer Conference showing more evidence that viruses may be responsible for lung cancer development.
In one report at the conference (Abstract No. 124PD; Friday 25th April, 09:50)Dr.Arash Rezazadeh and colleagues from the University of Louisville, Kentucky, USA, describe the results of a study on 23 lung cancer samples from patients in Kentucky.The researchers found six samples that tested positive for the presence of human papilloma virus (HPV), the virus that also causes many cases of cervical cancer. One was later shown to be a cervical cancer that had spread to the lungs.
Of the remaining 5 virus-positive samples, two were HPV type 16, two were HPV type 11 and one was HPV type 22. "The fact that five out of 22 non-small-cell lung cancer samples were HPV-positive supports the assumption that HPV contributes to the development of non-small-cell lung cancer," the authors say.
All the patients in this study were also smokers, Dr. Rezazadeh notes. "We think HPV has a role as a co-carcinogen which increases the risk of cancer in a smoking population," he says.
In another paper (Abstract No. 125PD; Friday 25th April, 09:50), Israeli researchers suggest that measles virus may also be a factor in some lung cancers. Their study included 65 patients with non-small-cell lung cancer, of whom more than half had evidence of measles virus in tissue samples taken from their cancer.
"Measles virus is a ubiquitous human virus that may be involved in the pathogenesis of lung cancer," says lead author Prof. Samuel Ariad from Soroka Medical Center in Beer Sheva, Israel. "Most likely, it acts in modifying the effect of other carcinogens and not as a causative factor by itself."
Press release from the European Society for Medical Oncology: Viruses may play a role in lung cancer development
Image credit: Wellcome images: Papilloma virus, human...
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The Social Ladder Is Really In Your Head
Researchers at the National Institutes of Health discovered how the brain seems to exhibit signs of hard wiring when reacting to events within the social hierarchy, like seeing one's superiors.
To find out, the NIMH researchers created an artificial social hierarchy in which 72 participants played an interactive computer game for money. They were assigned a status that they were told was based on their playing skill. In fact, the game outcomes were predetermined and the other "players" simulated by computer. While their brain activity was monitored by fMRI, participants intermittently saw pictures and scores of an inferior and a superior "player" they thought were simultaneously playing in other rooms.Although they knew the perceived players' scores would not affect their own outcomes or reward — and were instructed to ignore them — participants' brain activity and behavior were highly influenced by their position in the implied hierarchy.
"The processing of hierarchical information seems to be hard-wired, occurring even outside of an explicitly competitive environment, underscoring how important it is for us," said Zink.
Key study findings included:
The area that signals an event's importance, called the ventral striatum, responded to the prospect of a rise or fall in rank as much as it did to the monetary reward, confirming the high value accorded social status.
Just viewing a superior human "player," as opposed to a perceived inferior one or a computer, activated an area near the front of the brain that appears to size people up — making interpersonal judgments and assessing social status. A circuit involving the mid-front part of the brain that processes the intentions and motives of others and emotion processing areas deep in the brain activated when the hierarchy became unstable, allowing for upward and downward mobility.
Performing better than the superior "player" activated areas higher and toward the front of the brain controlling action planning, while performing worse than an inferior "player" activated areas lower in the brain associated with emotional pain and frustration.
The more positive the mood experienced by participants while at the top of an unstable hierarchy, the stronger was activity in this emotional pain circuitry when they viewed an outcome that threatened to move them down in status. In other words, people who felt more joy when they won also felt more pain when they lost.
Press release: Human Brain Appears "Hard-Wired" for Hierarchy
Photo courtesy of Erik van der Neut.
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Trigger in Heparin Deaths Identified
An international group of investigators identified oversulphated chondroitin sulphate, a contaminant found in vials of heparin from China linked to a recent series of deaths, as a triggering agent. In the picture, oversulphated chondroitin sulphate is a top molecule, and regular heparin is the lower image.
From the statement by MIT:
The team, led by Professor Ram Sasisekharan of MIT, identified the chemical structure of the contaminant, known as oversulfated chondroitin sulfate (OSCS). The researchers present their findings and offer new approaches to detecting the contaminant in a report appearing today in the online edition of Nature Biotechnology.Another team led by Sasisekharan has shown exactly how OSCS can kill--specifically by setting off an allergy-like reaction. The biological effects of the contaminant are outlined in a report also being published online today in the New England Journal of Medicine.
"Sophisticated analytical techniques enabled complete characterization of the contaminant present in heparin. Further, this study also provides the scientific groundwork for critical improvements in screening practices that can now be applied to monitor heparin, thus ensuring patient safety," said Sasisekharan, senior author of the papers, the Underwood Prescott Professor of Biological Engineering and Health Sciences and Technology at MIT and at the David H. Koch Institute for Integrative Cancer Research at MIT.
Heparin, a blood thinner often used during kidney dialysis or heart surgery, is normally produced from pig intestines. FDA officials say the contaminated heparin came from factories in China that manufacture the drug for Baxter International.
Baxter recalled its heparin in February after dozens of deaths were reported, dating back to November. The tainted heparin has been blamed for 81 U.S. deaths so far, and earlier this week, the FDA announced that contaminated batches were also found in 10 other countries.
The New England Journal of Medicine study offers the first potential link between the contaminant and the reported deaths. The researchers found that the contaminated heparin activates two inflammatory pathways, causing severe allergic reactions and low blood pressure.
"These results provide a potential link between the presence of chemical contaminant in heparin and the clinical symptoms observed in affected patients. Our findings also suggest that a simple bioassay could help protect the global supply chain of heparin, by screening heparin lots for the presence of polysulfated contaminants that may have unintended pharmacological consequences," said Sasisekharan.
Heparin consists of a long, complex chain of repeating sugar molecules. The contaminant, which is derived from animal cartilage, has a structure very similar to that of heparin and thus cannot be identified with the tests normally used to inspect batches of heparin.
It is unclear whether the contaminant got into the heparin during the manufacturing process, or how and where contamination could have occurred during the process. More investigations are needed to address this issue.
Traditional heparin safety screens test only for contaminants such as protein, lipids or DNA, and thus would not detect the presence of sugar chains that do not belong. Sasisekharan's laboratory has played a key role in developing new technologies for analyzing complex sugars. Using the new technology, the research team was able to detect the presence of the faulty sugars.
"In addition to being vital for public health, identifying the recent impurity in heparin was a chemical triumph," said Jeremy M. Berg, director of the National Institute of General Medical Science, which supported the work. "The research team accomplished this difficult task by using a unique combination of scientific techniques that might in the future be used to detect other impurities in pharmaceutical materials."
More than 100 patients have experienced adverse reactions after receiving the tainted heparin. Symptoms include extremely low blood pressure, swelling of the skin and mucus membranes, shortness of breath, and abdominal pain.
The researchers found that the contaminant activates two inflammatory pathways: one that initiates blood clotting and dilation of the blood vessels, and one that produces anaphylactic toxins. The first leads to a dangerous decrease in blood pressure, the second a serious allergic reaction. In blinded laboratory tests, the contaminated heparin activated the biological pathways, while normal heparin did not.
Sasisekharan emphasized the remarkable willingness of dozens of scientists across the globe to work together to rapidly resolve what might otherwise have left people with serious uncertainties about drug safety.
"The generosity and willingness of people to do whatever they could to help solve this problem was unlike anything I'd experienced before. It is extremely satisfying to see how teamwork has resulted in the application of rigorous, peer-reviewed science that helps to keep our medicines safe," he said.
Sasisekharan expressed his hope that such effective teamwork will extend to other dimensions of public health, in which rigorous team-based science leads not only toward safer drugs, but also toward safer foods and a safer environment.
Researchers from the FDA, Momenta Pharmaceuticals of Cambridge, Mass., Rensselaer Polytechnic Institute and the Istituto di Recherche Chimiche e Biochimiche of Milan, Italy, also contributed to the Nature Biotechnology paper.
Researchers from the FDA, Momenta Pharmaceuticals, Virginia-Maryland Regional College of Veterinary Medicine at Virginia Tech, and Brigham and Women's Hospital contributed to the New England Journal of Medicine paper.
MIT: Teams unravel heparin death mystery...
More from Nature: Trigger in heparin deaths confirmed...
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Wednesday, April 23, 2008
Claim: Mother's Diet May Determine Child's Gender
Expecting fathers, hoping to have a baby boy, may consider pampering their wives with fancy breakfasts in bed, as it may be the only method known to science to help influence the sex of the child. Scientists at the Universities of Exeter and Oxford found a correlation between a mother's high energy diet and an increased chance of having a male child.
The study focused on 740 first-time pregnant mothers in the UK, who did not know the sex of their fetus. They were asked to provide records of their eating habits before and during the early stages of pregnancy. They were then split into three groups according to the number of calories consumed per day around the time they conceived. 56% of the women in the group with the highest energy intake at conception had sons, compared with 45% in the lowest group. As well as consuming more calories, women who had sons were more likely to have eaten a higher quantity and wider range of nutrients, including potassium, calcium and vitamins C, E and B12. There was also a strong correlation between women eating breakfast cereals and producing sons.Over the last 40 years there has been a small but consistent decline, of about one per 1000 births annually, in the proportion of boys being born in industrialised countries, including the UK, the USA and Canada. Previous research has also shown a reduction in the average energy intake in the developed world. The ‘obesity epidemic’ is largely ascribed to declines in physical activity and differences in food quality and eating habits. There is also evidence that skipping breakfast is now common in the developed world: in the USA, the proportion of adults eating breakfast fell from 86% to 75% between 1965 and 1991.
Dr Fiona Mathews of the University of Exeter, lead author on the paper, said: “This research may help to explain why in developed countries, where many young women choose to have low calorie diets, the proportion of boys born is falling. Our findings are particularly interesting given the recent debates within the Human Fertilisation and Embryology Committee about whether to regulate ‘gender’ clinics that allow parents to select offspring sex, by manipulating sperm, for non-medical reasons. Here we have evidence of a ‘natural’ mechanism that means that women appear to be already controlling the sex of their offspring by their diet.”
Scientists already know that in many animals, more sons are produced when a mother has plentiful resources or is high ranking. The phenomenon has been most extensively studied in invertebrates, but is also seen in horses, cows and some species of deer. The explanation is thought to lie with the evolutionary drive to produce descendants.
University of Exeter press release: You are what your mother eats ...
Abstract: You are what your mother eats: evidence for maternal preconception diet influencing foetal sex in humans Proc. R. Soc. B
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fMRI Scanners Used to Detect Wandering Mind
Using functional MRI machines researchers at the University of Bergen in Norway detected how the brain sails off on its own course during mental activity, a process that produces inattention and leads to mistakes.
The recordings revealed a cascade of shifting activity in the parts of the brain associated with focusing attention and maintaining routines. Researchers observed test subjects' minds going on autopilot up to half a minute before the subjects actually made mistakes, even though the subjects weren't aware of their own lapses of attention.If the same mechanisms produce other, more meaningful errors -- slips on the assembly line or behind a steering wheel -- then the research could be used to design biofeedback systems that could catch mistakes before they're made.
"People could be made aware that they're not in the best condition to be working. Or people might learn to identify their 'bad' brain state," said study co-author Tom Eichele, a neuroscientist at the University of Bergen in Norway.
Up to 30 seconds before Eichele's test subjects carelessly said that an arrow pointing in one direction was pointing in another, blood flow decreased in their posterior medial frontal cortex, a brain region associated with sustaining effort and focus.
At the same time, activity increased in the so-called default mode network -- a region of the brain spanning the precuneus, retrosplenial cortex and anterior medial frontal cortex. The default mode network is associated with maintaining baseline routines, and tends to be most active during sleep and sedation.
More from Wired...
(hat tip: Engadget)
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Defense Department Sponsors Aggressive Stem Cell Research
The US military is initiating a major research project to develop regenerative medicine technologies, that will hopefully allow for regrowth of tissues, skin, and body parts.
The newly established Armed Forces Institute of Regenerative Medicine, known by the acronym AFIRM, will serve as the military's operational agency for the effort, Dr. S. Ward Casscells, the assistant secretary of defense for health affairs, told reporters at a Pentagon news conference.A key component of the initiative is to harness stem cell research and technology in finding innovative ways to use a patient's natural cellular structure to reconstruct new skin, muscles and tendons, and even ears, noses and fingers, Casscells said.
AFIRM will fall under the auspices of the U.S. Army Medical Research and Material Command, based at Fort Detrick, Md., and it also will work in conjunction with U.S. Army Institute of Surgical Research, in San Antonio.
The Medical Research and Material Command is the Army's lead medical research, development and related-material acquisition agency. It comes under U.S. Army Medical Command, which is led by Lt. Gen. Eric B. Schoomaker, the Army's surgeon general.
Press release: Regenerative Medicine Seen as Means to Repair Wounded Warriors ...
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(hat tip: Engadget)
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Tuesday, April 22, 2008
The Search for Breast Cancer Biomarkers
At the Pacific Northwest National Laboratory, scientists are harnessing mass spectrometers in attempts to systematically identify breast cancer biomarkers that might be present in the blood of sufferers.
Although scientists have identified two genes that predispose young women to breast cancer, the vast majority of cases in pre-menopausal women have no obvious genetic link. A blood-borne biomarker would add substantially to the tools available to fight the disease. Many groups are looking for such biomarkers, but access to a 30,000-sample blood and tissue collection, and cutting-edge high-throughput proteomics sets this project apart."We're lookin