Scientists grow cartilage to reconstruct nose

Scientists at the University of Basel report first ever successful nose reconstruction surgery using cartilage grown in the laboratory. Cartilage cells were extracted from the patient’s nasal septum, multiplied and expanded onto a collagen membrane. The so-called engineered cartilage was then shaped according to the defect and implanted. The results will be published in the current edition of the academic journal The Lancet.A research team from the University of Basel in Switzerland has reported that nasal reconstruction using engineered cartilage is possible. They used a method called tissue engineering where cartilage is grown from patients’ own cells. This new technique was applied on five patients, aged 76 to 88 years, with severe defects on their nose after skin cancer surgery. One year after the reconstruction, all five patients were satisfied with their ability to breathe as well as with the cosmetic appearance of their nose. None of them reported any side effects.Cells from the nasal septumThe type of non-melanoma skin cancer investigated in this study is most common on the nose, specifically the alar wing of the nose, because of its cumulative exposure to sunlight. To remove the tumor completely, surgeons often have to cut away parts of cartilage as well. Usually, grafts for reconstruction are taken from the nasal septum, the ear or the ribs and used to functionally reconstruct the nose. …

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Human and dog brains both have dedicated ‘voice areas’

The first study to compare brain function between humans and any nonprimate animal shows that dogs have dedicated voice areas in their brains, just as people do. Dog brains, like those of people, are also sensitive to acoustic cues of emotion, according to a study in the Cell Press journal Current Biology on February 20.The findings suggest that voice areas evolved at least 100 million years ago, the age of the last common ancestor of humans and dogs, the researchers say. It also offers new insight into humans’ unique connection with our best friends in the animal kingdom and helps to explain the behavioral and neural mechanisms that made this alliance so effective for tens of thousands of years.”Dogs and humans share a similar social environment,” says Attila Andics of MTA-ELTE Comparative Ethology Research Group in Hungary. “Our findings suggest that they also use similar brain mechanisms to process social information. This may support the successfulness of vocal communication between the two species.”Andics and his colleagues trained 11 dogs to lay motionless in an fMRI brain scanner. That made it possible to run the same neuroimaging experiment on both dog and human participants — something that had never been done before. They captured both dogs’ and humans’ brain activities while the subjects listened to nearly 200 dog and human sounds, ranging from whining or crying to playful barking or laughing.The images show that dog and human brains include voice areas in similar locations. Not surprisingly, the voice area of dogs responds more strongly to other dogs while that of humans responds more strongly to other humans.The researchers also noted striking similarities in the ways the dog and human brains process emotionally loaded sounds. In both species, an area near the primary auditory cortex lit up more with happy sounds than unhappy ones. Andics says the researchers were most struck by the common response to emotion across species.There were some differences, too: in dogs, 48% of all sound-sensitive brain regions respond more strongly to sounds other than voices. …

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Better broccoli, enhanced anti-cancer benefits with longer shelf life

While researching methods to increase the already well-recognized anti-cancer properties of broccoli, researchers at the University of Illinois also found a way to prolong the vegetable’s shelf life.And, according to the recently published study, the method is a natural and inexpensive way to produce broccoli that has even more health benefits and won’t spoil so quickly on your refrigerator shelf.Jack Juvik, a U of I crop sciences researcher, explained that the combined application of two compounds, both are natural products extracted from plants, increased the presence of cancer-fighting agents in broccoli while prolonging the post-harvest storage period.”We had figured out ways to increase the anti-cancer activity in broccoli, but the way we figured it out created a situation that would cause the product to deteriorate more rapidly after application,” Juvik said. “For fresh-market broccoli that you harvest, it’s not too big a deal, but many of these products have to be shipped, frozen, cut up, and put into other products. Usually the idea is to get it from the farm to at least the distributor (grocery store) within two to three days.”If we could figure out a way to prolong the appearance, taste, and flavor long after harvest and maintain the improved health-promoting properties, that’s always of great interest to growers,” he added.The researchers first used methyl jasmonate (MeJA), a non-toxic plant-signal compound (produced naturally in plants) to increase the broccoli’s anti-cancer potential, which they sprayed on the broccoli about four days before harvest. When applied, MeJA initiates a process of gene activity affiliated with the biosynthesis of glucosinolates (GS), which are compounds found in the tissue of broccoli and other brassica vegetables (such as cauliflower, cabbage, and kale).Glucosinolates have been identified as potent cancer-preventative agents because of their ability to induce detoxification enzymes, such as quinone reductase (QR), that detoxify and eliminate carcinogens from the human body.However, during this process, MeJA also signals a network of genes that lead to plant decay by inducing the release of ethylene, Juvik explained. “While we can use MeJA to turn on phytochemicals like the glucosinolates and dramatically increase the abundance of those helpful anti-cancer compounds, MeJA also reduces the shelf life after harvest,” he said.So the researchers tried using the recently developed compound 1-methylcyclopropene (1-MCP), which has been shown to interfere with receptor proteins in the plant that are receptor-sensitive to ethylene. They applied the compound after harvesting the same broccoli that had already been treated with MeJA before harvest.”Ethylene will move and bind to ethylene receptors and that binding process initiates decay. What this compound does is that it more competitively lands on the protein and binds to or pushes out ethylene,” Juvik explained. “It basically stops or dramatically slows down the decay associated with ethylene.”The combination is good,” he said.Like MeJA, 1-MCP is also a non-toxic compound naturally produced in plants, although Juvik said synthetic forms can be produced. He stressed that both the MeJA and 1-MCP treatments required very small amounts of the compounds.”It’s very cheap, and it’s about as toxic as salt. It takes very little to elevate all the desirable aspects. …

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Grasshoppers are what they eat: New method to extract plant DNA from grasshopper guts sheds light on plant-insect interactions

Grasshoppers may be small, but the damages they are causing to the U.S. agriculture industry are anything but. Every year, they feed on crops and on rangelands needed for raising livestock, costing landowners millions of dollars. Although they pose a major threat, grasshopper populations play a positive role in cycling nutrients from decomposing plant matter back into the soil. A new method to investigate their feeding patterns could be the key to a better understanding of the impact of grasshoppers on plant communities.”The main problem with current control methods is the damage done to non-target plant and insect species,” says University of Cincinnati researcher Alina Avanesyan, who developed the new protocol while studying grasshopper leaf tissue consumption. “Accurately determining the feeding preferences of grasshoppers can help us to understand the magnitude of plant damage, and consequently, whether or not control of grasshoppers is needed in a given area.”The method recovers high-quality DNA of ingested plant tissue from grasshopper guts. This plant DNA offers valuable information about grasshopper diets because it holds more data than what can be observed by the naked eye. Scientists can use it to compare specific feeding patterns between different grasshopper species and uncover behaviors that might lead to intensive crop damage in certain areas. A detailed description of the dissection and DNA extraction, including a video illustrating the dissection technique, can be viewed in the February issue of Applications in Plant Sciences.According to Avanesyan, “With this protocol, a researcher can focus on a variety of research questions, such as detecting plant-insect interactions, determining how long the food has been digested, estimating the prevalence of different plants in insect guts, exploring the sequence of multiple plant species consumed, and inferring feeding preferences.”The protocol begins with a basic dissection kit used to isolate the grasshopper guts. A DNA extraction is then performed on the gut components, which results in a combination of grasshopper and plant DNA. …

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Mesothelioma Treatment Options

Mesothelioma Treatment OptionsBy Garry NealeMesothelioma is a cancer caused by contact with asbestos, a carcinogen. The disease attacks the lining of the lung or the lining of the abdominal cavity. It can be difficult to deal with this type of cancer and find decent mesothelioma info online. This article will outline some of the main treatment options available to deal with the disease. The more knowledge you have about this disease, the better.Most people searching for mesothelioma info are looking for information regarding the different treatments currently available to those affected by the cancer. The type of treatment you receive for it depends on many factors, including cancer stage, location of the disease, and how far it has spread. It also depends on how the cancer …

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Scientists use blur to sharpen DNA mapping

Oct. 9, 2013 — With high-tech optical tools and sophisticated mathematics, Rice University researchers have found a way to pinpoint the location of specific sequences along single strands of DNA, a technique that could someday help diagnose genetic diseases.Proof-of-concept experiments in the Rice lab of chemist Christy Landes identified DNA sequences as short as 50 nucleotides at room temperature, a feat she said is impossible with standard microscopes that cannot see targets that small, or electron microscopes that require targets to be in a vacuum or cryogenically frozen.The technique called “super-localization microscopy” has been known for a while, Landes said, but its application in biosensing is just beginning. Scientists have seen individual double-stranded DNA molecules under optical microscopes for years, but the ability to see single-stranded DNA is a new achievement, and breaking the diffraction limit of light adds value, she said.The work by Landes, Rice postdoctoral associate Jixin Chen and undergraduate student Alberto Bremauntz is detailed in the American Chemical Society journal Applied Materials and Interfaces.The Rice researchers call their super-resolution technique “motion blur point accumulation for imaging in nanoscale topography” (mbPAINT). With it, they resolved structures as small as 30 nanometers (billionths of a meter) by making, essentially, a movie of fluorescent DNA probes flowing over a known target sequence along an immobilized single strand of DNA.The probes are labeled with a fluorescent dye that lights up only when attached to the target DNA. In the experimental setup, most would flow by unseen, but some would bind to the target for a few milliseconds, just long enough to be captured by the camera before the moving liquid pulled them away. Processing images of these brief events amidst the background blur allows the researchers to image objects smaller than the natural diffraction limits of light-based imaging, which do not allow for the resolution of targets smaller than the wavelength of light used to illuminate them.Even the Landes lab’s system is subject to these physical limitations. Individual images of fluorescing probes on targets are just a pixelated blur. But it’s a blur with a bright spot, and careful analysis of multiple images allows the researchers to pinpoint that spot along the strand.”The probes are moving so fast that in real time, all we would see with the camera is a line,” Chen said. But when the camera firing at 30-millisecond intervals happened to catch a bound probe, it clearly stood out. The probes sometime picked out two sequences along a strand that would have been seen as a single blur via regular fluorescent microscopy.Landes said one goal for mbPAINT is to map ever-smaller fragments of DNA. …

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Breakthrough discerns normal memory loss from disease

Sep. 11, 2013 — Cornell University researchers have developed a reliable method to distinguish memory declines associated with healthy aging from the more-serious memory disorders years before obvious symptoms emerge. The method also allows research to accurately predict who is more likely to develop cognitive impairment without expensive tests or invasive procedures.Their results hold promise for detecting cognitive impairment early and monitoring treatment, but also have implications for healthy adults, said Charles Brainerd, professor of human development and the study’s lead co-author with Valerie Reyna, director of the Institute for Human Neuroscience and professor of human development, both in Cornell’s College of Human Ecology.Their research, “Dual-retrieval models and neurocognitive impairment,” appears online in the Journal of Experimental Psychology: Learning, Memory and Cognition.The memory abilities affected by cognitive impairment differ from those affected by healthy aging, the authors say, resulting in unique error patterns on neuropsychological tests of memory. Their theory-driven mathematical model detects these patterns by analyzing performance on such tests and measuring the separate memory processes used.”With 10 or 15 minute recall tests already in common use worldwide, we can distinguish individuals who have or are at risk for developing cognitive impairment from healthy adults, and we can do so with better accuracy than any existing tools,” said Brainerd.The notion that memory declines continuously throughout adulthood appears to be incorrect, they say. “When we separated out the cognitively impaired individuals, we found no evidence of further memory declines after the age of 69 in samples of nationally representative older adults and highly educated older adults,” said Reyna.To develop their models, the team used data from two longitudinal studies of older adults — a nationally representative sample of older adults, the Aging, Demographics and Memory Study, and the Alzheimer’s Disease Neuroimaging Initiative — that include brain and behavioral measures as well as diagnoses for cognitive impairment and dementia.Specifically, the researchers found that declines in reconstructive memory (recalling a word or event by piecing it together from clues about its meaning, for example, recalling that “dog” was presented in a word list by first remembering that household pets were presented in the list) were associated with mild cognitive impairment and Alzheimer’s dementia, but not with healthy aging. Declines in recollective memory — recalling a word or event exactly — were a feature of normal aging.Over a period of between one and a half to six years, declines in reconstructive memory processes were reliable predictors of future progression from healthy aging to mild cognitive impairment and Alzheimer’s dementia, and better predictors than the best genetic marker of such diseases.”Reconstructive memory is very stable in healthy individuals, so declines in this type of memory are a hallmark of neurocognitive impairment,” Reyna said.Younger adults rely heavily on recollection, Brainerd said, but this method becomes increasingly inefficient throughout mid-adulthood. “Training people how to make better use of reconstructive recall as they age should assist healthy adult memory function,” he said. “Our analytical models are readily available for research and clinical use and could easily be incorporated into existing neuropsychological tests.”

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Mosquito bites deliver potential new malaria vaccine

Sep. 11, 2013 — A study published in Vaccine could provide hope for new live-attenuated malaria vaccineThis study suggests that genetically engineered malaria parasites that are stunted through precise gene deletions (genetically attenuated parasites, or “GAP”) could be used as a vaccine that protects against malaria infection. This means that the harmless (attenuated) version of the parasite would interact with the body in the same way as the infective version, but without possibility of causing disease. GAP-vaccination would induce robust immune responses that protect against future infection with malaria.According to the World Health Organization, there were 219 million documented cases of malaria in 2010, causing the deaths of up to 1.2 million people worldwide. Antimalarial treatments are available to reduce the risk of infection, but as yet there is no effective vaccine against the disease.Last month, a team of scientists announced the results of a trial with a new kind of malaria vaccine, a whole-parasite preparation weakened by radiation. The trial showed promising results, but the method of vaccination was not optimal, requiring intravenous administration and multiple high doses. This current paper outlines a method of attenuation through genetic engineering rather than radiation, which offers hope for a more consistent vaccine that gives better protection.”Malaria is one of the world’s biggest killers, and threatens 40 percent of the world’s population, yet still no effective vaccine exists,” said Stefan Kappe, Ph.D., lead author of the paper and professor at Seattle BioMed. “In this paper we show that genetically engineered parasites are a promising, viable option for developing a malaria vaccine, and we are currently engineering the next generation of attenuated parasite strains with the aim to enter clinical studies soon.”For the first time, researchers created a weakened version of the human malaria parasite by altering its DNA. They tested the safety of the new modified parasite by injecting six human volunteers through mosquito bites. Five of the six volunteers showed no infection with the parasite, suggesting that the new genetic technique has potential as the basis for a malaria vaccine.”Our approach offers a new path to make a protective malaria vaccine that might overcome the limitations of previous development attempts. …

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Possibility of selectively erasing unwanted memories

Sep. 10, 2013 — The human brain is exquisitely adept at linking seemingly random details into a cohesive memory that can trigger myriad associations — some good, some not so good. For recovering addicts and individuals suffering from post-traumatic stress disorder (PTSD), unwanted memories can be devastating. Former meth addicts, for instance, report intense drug cravings triggered by associations with cigarettes, money, even gum (used to relieve dry mouth), pushing them back into the addiction they so desperately want to leave.Now, for the first time, scientists from the Florida campus of The Scripps Research Institute (TSRI) have been able to erase dangerous drug-associated memories in mice and rats without affecting other more benign memories.The surprising discovery, published this week online ahead of print by the journal Biological Psychiatry, points to a clear and workable method to disrupt unwanted memories while leaving the rest intact.”Our memories make us who we are, but some of these memories can make life very difficult,” said Courtney Miller, a TSRI assistant professor who led the research. “Not unlike in the movie Eternal Sunshine of the Spotless Mind, we’re looking for strategies to selectively eliminate evidence of past experiences related to drug abuse or a traumatic event. Our study shows we can do just that in mice — wipe out deeply engrained drug-related memories without harming other memories.”Changing the Structure of MemoryTo produce a memory, a lot has to happen, including the alteration of the structure of nerve cells via changes in the dendritic spines — small bulb-like structures that receive electrochemical signals from other neurons. Normally, these structural changes occur via actin, the protein that makes up the infrastructure of all cells.In the new study, the scientists inhibited actin polymerization — the creation of large chainlike molecules — by blocking a molecular motor called myosin II in the brains of mice and rats during the maintenance phase of methamphetamine-related memory formation.Behavioral tests showed the animals immediately and persistently lost memories associated with methamphetamine — with no other memories affected.In the tests, animals were trained to associate the rewarding effects of methamphetamine with a rich context of visual, tactile and scent cues. When injected with the inhibitor many days later in their home environment, they later showed a complete lack of interest when they encountered drug-associated cues. At the same time, the response to other memories, such as food rewards, was unaffected.While the scientists are not yet sure why powerful methamphetamine-related memories are also so fragile, they think the provocative findings could be related to the role of dopamine, a neurotransmitter involved in reward and pleasure centers in the brain and known to modify dendritic spines. Previous studies had shown dopamine is released during both learning and drug withdrawal. …

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Early detection of Parkinson’s disease through handwriting

Sep. 9, 2013 — Today’s primary tool for diagnosing Parkinson’s disease is the diagnostic ability of the physician, who can generally identify the clinical symptoms only when the disease is at a relatively advanced stage. A new joint study by researchers at the University of Haifa and Rambam Hospital that compared the handwriting of 40 sick and healthy subjects suggests an innovative and noninvasive method of diagnosing Parkinson’s at a fairly early stage.“Identifying the changes in handwriting could lead to an early diagnosis of the illness and neurological intervention at a critical moment,” explains Prof. Sara Rosenblum, of the University of Haifa’s Department of Occupational Therapy, who initiated the study.The methods for diagnosing Parkinson’s today are a physician evaluation or a test called SPECT, which uses radioactive material to image the brain. The latter, however, is no more effective in diagnosing the illness than an expert doctor and it exposes the patient to unnecessary radiation.Studies from recent years show that there are unique and distinctive differences between the handwriting of patients with Parkinson’s disease and that of healthy people. However, most studies that to date have focused on handwriting focused on motor skills (such as the drawing of spirals) and not on writing that involves cognitive abilities, such as signing a check, copying addresses, etc.According to Prof. Rosenblum, Parkinson’s patients report feeling a change in their cognitive abilities before detecting a change in their motor abilities and therefore a test of cognitive impairment like the one performed in this study could attest to the presence of the disease and offer a way to diagnose it earlier.This research was conducted in cooperation with Dr. Ilana Schlesinger, head of the Center for Movement Disorders and Parkinson’s Disease at Haifa’s Rambam Medical Center and occupational therapists working in the hospital. In the study, the researchers asked the subjects to write their names and gave them addresses to copy, two everyday tasks that require cognitive abilities. Participants were 40 adults with at least 12 years of schooling, half healthy and half known to be in the early stages of Parkinson’s disease (before obvious motor signs are visible).The writing was done on a regular piece of paper that was placed on electronic tablet, using a special pen with pressure-sensitive sensors operated by the pen when it hit the writing surface. …

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Novel method to identify suitable new homes for animals under threat from climate change

Sep. 5, 2013 — Scientists at the Zoological Society of London (ZSL) have devised a novel method to identify suitable new homes for animals under threat from climate change.Conservation scientists used their knowledge on species ecology to create habitat suitability maps and correctly identify sites that will remain viable in the future regardless of changing climate. However, the key for success is to understand, and account for, the link between variation in species population size, climate and how the climate may change.Almost half of all bird and amphibian species are believed to be highly vulnerable to extinction from climate change. Species in extreme or rare habitats such as the emperor penguin in the Antarctic and American pika in the USA have already experienced drastic declines in populations due to the impact of climate change on their home.As climate changes, many species will need to move to a different location in order to survive. For species that aren’t able to do this naturally, the only chance of survival is a helping hand through the use of translocations.The research is published today (6 September) in the Journal of Applied Ecology.Dr Nathalie Pettorelli, ZSL’s climate change coordinator and senior author on the paper, says: “Climate change poses a worrying threat to many animals, and relocating vulnerable species to new and more suitable habitats may be the only way to protect them. However, this is an extreme conservation action, which needs to be thoroughly justified, and requires clear guidance on where threatened populations should be moved. Our research shows how these key requirements can be met.”The team used the hihi bird as an example because of the conservation success which came after efforts put into its relocation since the 1980s. Yet, despite large investments into its protection, climate change is now posing a significant threat to its future survival.Dr Alienor Chauvenet, lead author of the study, says: “All current hihi populations are surrounded by either a large stretch of water or unsuitable habitat such as farmland or cities with plenty of non-native predators. This isolation makes it very perilous for them to move and individuals attempting to relocate naturally are unlikely to survive.”Our work shows that assisted colonisation may be the only way to guarantee the survival of this unique species under climate change,” Dr Chauvenet added.Translocations will continue to be an important part of conservation as climate changes. ZSL’s novel method shows how these interventions can be planned to be successful even under the influence of a changing environment. …

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Pico-world of molecular bioscavengers, mops and sponges being designed

Sep. 5, 2013 — Protein molecule ‘dragnets’ were designed on computers and built in a lab to recognize and unite with small moleculesComputer-designed proteins that can recognize and interact with small biological molecules are now a reality. Scientists have succeeded in creating a protein molecule that can be programmed to unite with three different steroids.The achievement could have far wider ranging applications in medicine and other fields, according to the Protein Design Institute at the University of Washington.”This is major step toward building proteins for use as biosensors or molecular sponges, or in synthetic biology — giving organisms new tools to perform a task,” said one of the lead researchers, Christine E. Tinberg, a postdoctoral fellow in biochemistry at the UW.The approach they took appears in the Sept. 4 online issue of Nature. Tinberg and Sagar D. Khare headed the study under the direction of David Baker, UW professor of biochemistry and Howard Hughes Medical Institute investigator. Khare is currently an assistant professor at Rutgers University.Their Nature paper is accompanied by a commentary, “Computational biology: A recipe for ligand binding proteins.” The commentator, Giovanna Ghirlanda of Arizona State University, wrote that the method developed “to design proteins with desired recognition sites could be revolutionary” because cell processes such as cell cross-talk, the production of gene products and the work of enzymes all depend on molecular recognition.The scientific team overcame previously unsolved problems in building accurate protein-small molecule interfaces. Earlier attempts struggled with discrepancies between the computer plans and the structures of the actual molecules.In conducting the study, the researchers learned general principles for engineering small molecule-binding proteins with strong attraction energies. Their findings open up the possibility that binding proteins could be created for many medical, industrial and environmental uses.In medical diagnostics, for example, a rationally programmed protein might detect biomolecules found only in a specific disease state, such as an early-stage cancer. …

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Mechanical chest compressions for cardiac arrest just as good as manual, study suggests

Sep. 1, 2013 — In the event of cardiac arrest outside of a hospital it is important to provide effective chest compressions without interruption. Creating blood flow reduces the risk of brain damage and improves the chances of survival. A new Swedish study shows that mechanical treatment yields results that are at least as good as manual treatment.The new findings are being presented today at the annual ESC (European Society of Cardiology) conference in Amsterdam. Research on cardiac arrest has focused for many years on improving treatment by increasing blood flow in cardiopulmonary resuscitation and by lowering the body temperature in order to limit brain damage and increase the chance of survival. In recent years there has been a growing interest in mechanical chest compression, and a few products are now available on the market. But there have been no rigorous scientific studies of their function.After a small pilot study in collaboration with the company that developed the LUCAS device for mechanical chest compressions, a comprehensive clinical study was started in 2008. The study looked at 2.589 patients with cardiac arrest from six ambulance areas in Sweden, the Netherlands, and England. They were randomly placed either in a group that received mechanical chest compressions or in a group that underwent traditional treatment with manual chest compressions according to guidelines.Patients’ survival and neurological condition were monitored from four hours after the cardiac arrest up to six months after they were discharged from hospital. The results show no significant differences between the groups — both groups survived to the same extent and in equally good neurological condition. …

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‘Mini human brains’ created: Scientists grow human brain tissue in 3-D culture system

Aug. 29, 2013 — Complex human brain tissue has been successfully developed in a three-dimensional culture system established in an Austrian laboratory. The method described in the current issue of Nature allows pluripotent stem cells to develop into cerebral organoids — or “mini brains” — that consist of several discrete brain regions.Instead of using so-called patterning growth factors to achieve this, scientists at the Institute of Molecular Biotechnology (IMBA) of the Austrian Academy of Sciences (OeAW) fine-tuned growth conditions and provided a conducive environment. As a result, intrinsic cues from the stem cells guided the development towards different interdependent brain tissues. Using the “mini brains,” the scientists were also able to model the development of a human neuronal disorder and identify its origin — opening up routes to long hoped-for model systems of the human brain.The development of the human brain remains one of the greatest mysteries in biology. Derived from a simple tissue, it develops into the most complex natural structure known to man. Studies of the human brain’s development and associated human disorders are extremely difficult, as no scientist has thus far successfully established a three-dimensional culture model of the developing brain as a whole. Now, a research group lead by Dr. Jürgen Knoblich at the Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA) has just changed that.Brain Size MattersStarting with established human embryonic stem cell lines and induced pluripotent stem (iPS) cells, the group identified growth conditions that aided the differentiation of the stem cells into several brain tissues. While using media for neuronal induction and differentiation, the group was able to avoid the use of patterning growth factor conditions, which are usually applied in order to generate specific cell identities from stem cells. …

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Could planting trees in the desert mitigate climate change?

July 31, 2013 — As the world starts feeling the effects of increasing atmospheric carbon dioxide and consequent global temperature rise, researchers are looking for a Plan B to mitigate climate change. A group of German scientists has now come up with an environmentally friendly method that they say could do just that. The technique, dubbed carbon farming, consists in planting trees in arid regions on a large scale to capture CO2.They publish their study today in Earth System Dynamics, a journal of the European Geosciences Union (EGU).”Carbon farming addresses the root source of climate change: the emission of carbon dioxide by human activities,” says first-author Klaus Becker of the University of Hohenheim in Stuttgart.”Nature does it better,” adds Becker’s colleague Volker Wulfmeyer, “if we understand and can make use of it in a sustainable manner.”When it comes to sequestering carbon from the atmosphere, the team shows that Jatropha curcas does it better. This small tree is very resistant to aridity so it can be planted in hot and dry land in soil unsuitable for food production. The plant does need water to grow though, so coastal areas where desalinated seawater can be made available are ideal.”To our knowledge, this is the first time experts in irrigation, desalination, carbon sequestration, economics and atmospheric sciences have come together to analyse the feasibility of a large-scale plantation to capture carbon dioxide in a comprehensive manner. We did this by applying a series of computer models and using data from Jatropha curcas plantations in Egypt, India and Madagascar,” says Wulfmeyer.The new Earth System Dynamics study shows that one hectare of Jatropha curcas could capture up to 25 tonnes of atmospheric carbon dioxide per year, over a 20 year period. A plantation taking up only about 3% of the Arabian Desert, for example, could absorb in a couple of decades all the CO2.produced by motor vehicles in Germany over the same period. With about one billion hectares suitable for carbon farming, the method could sequester a significant portion of the CO2.added to the atmosphere since the industrial revolution.But there are more advantages. Carbon farming’s price tag ranges from 42 to 63 euros per tonne of CO2. making it competitive with other CO2.reduction techniques such as carbon capture and storage. …

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Number one source for new teeth

July 29, 2013 — Stem cells derived from urine can be used to generate tooth-like structures, reports a study published this week in the open access Cell Regeneration Journal. It’s thought the technique might one day help researchers grow new, tailor-made teeth for dental patients.That stem cells can be generated from urine is not new; previous studies have shown that cells discarded in human urine can be coaxed to become induced pluripotent stem cells (iPSCs), which themselves can generate many different cell types, including neurons and heart muscle cells. But researchers had yet to generate solid organs or tissues from iPSCs — until now.Duanqing Pei and colleagues have developed a novel chimeric tissue culture system to coax human urine-derived iPSCs into tiny structures that resemble teeth. The system mimics normal tooth development, which results from an interaction between two different cell types; epithelial cells, which give rise to enamel, and mesenchymal cells, which give rise to the other three main components of teeth (dentin, cementum and pulp).First, the team used chemicals to coax the cultured iPSCs into flat sheets of epithelial cells. They then mixed these cells with mouse embryonic mesenchymal cells, and transplanted them into mice. Three weeks later, tooth-like structures had grown.The primitive teeth-like organs are structurally and physically similar to human teeth. They are of roughly the same elasticity, and contain pulp, dentin and enamel-forming cells. But the method has its limitations — it involves mouse cells, has a success rate of around 30% and the structures were about one-third of the hardness of human teeth.To resolve these issues, human mesenchymal stem cells could be substituted for mouse ones and the tissue culture conditions tweaked. The revised method could, in theory, be used to create a bioengineered tooth bud that could be cultured in vitro then transplanted into the jawbone of a needy patient to form a fully functional tooth.iPSCs are of interest over embryonic stem cells because their derivation avoids the controversial use of embryos. iPSCs have previously been derived from cultured skin and blood cells, but urine represents an more readily accessible source. …

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New modular vaccine design combines best of existing vaccine technologies

July 29, 2013 — A new method of vaccine design, called the Multiple Antigen Presentation System (MAPS), may result in vaccines that bring together the benefits of whole-cell and acellular or defined subunit vaccination. The method, pioneered by researchers at Boston Children’s Hospital, permits rapid construction of new vaccines that activate mulitple arms of the immune system simultaneously against one or more pathogens, generating robust immune protection with a lower risk of adverse effects.As reported by Fan Zhang, PhD, Ying-Jie Lu, PhD, and Richard Malley, MD, from Boston Children’s Division of Infectious Disease, in the Proceedings of the National Academy of Sciences on July 29, the method could speed development of new vaccines for a range of globally serious pathogens, or infectious agents.Broadly speaking, the vaccines available today fall into two categories: whole-cell vaccines, which rely on weakened or killed bacteria or viruses; and acellular or subunit vaccines, which include a limited number of antigens — portions of a pathogen that trigger an immune response. Both approaches have advantages and disadvantages.”Whole-cell vaccines elicit a broad range of immune responses, often just as an infection would, but can cause side effects and are hard to standardize,” said Malley. “Acellular vaccines can provide good early immunity with less risk of side effects, but the immune responses they induce wane with time.”The MAPS method may allow vaccine developers to take a middle ground, where they can link multiple protein and polysaccharide (sugar) antigens from one or more pathogens together in a modular fashion, much as one would connect Lego blocks.The resulting complex — which resembles a scaffold of polysaccharides studded with proteins — can stimulate both antibody and T-cell responses simultaneously much like whole-cell vaccines, resulting in stronger immunity to the source pathogen(s). However, because the composition of a MAPS vaccine is well defined and based on the use of isolated antigens (as one would find with an acellular vaccine) the risk of side effects should be greatly reduced.For instance, mice injected with a MAPS vaccine combining proteins from tuberculosis (TB) and polysaccharides from Streptococcus pneumoniae (pneumococcus) mounted vigorous antibody and T-cell responses against TB, whereas those vaccinated with TB protein antigens alone mounted only an antibody response.Similarly, 90 percent of mice given a MAPS-based vaccine containing multiple pneumococcal polysaccharide and protein antigens were protected from a lethal pneumococcus infection, mounting strong antibody and T-cell responses against the bacteria. By contrast, 30 percent of mice vaccinated with the same antigens in an unbound state survived the same challenge.”The MAPS technology gives you the advantages of: whole-cell vaccines while being much more deliberate about which antigens you include; doing it in a quantitative and precise way; and including a number of antigens so as to try to replicate the effectiveness of whole-cell vaccination,” Malley explained. “The immunogenicity of these constructs is greater than the sum of their parts, somewhat because they are presented to the host as particles.”The system relies on the interactions of two compounds, biotin and rhizavidin, rather than covalent binding as is used in most of the current conjugate vaccines. To build a MAPS vaccine, biotin is bound to the polysaccharide(s) of choice and rhizavidin to the protein(s). The biotin and rhizavidin then bind together through an affinity interaction analogous to Velcro. The construction process is highly efficient, significantly reducing the time and cost of vaccine development and production.While his team’s initial work has focused on bacterial pathogens, Malley believes the technology could impact vaccine development for a broad range of pathogens, in particular those of importance in the developing world. …

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New method rapidly identifies specific strains of illness

July 10, 2013 — Researchers from Boston University School of Medicine (BUSM) and George Washington University (GWU) have developed a method to rapidly identify pathogenic species and strains causing illnesses, such as pneumonia, that could help lead to earlier detection of disease outbreaks and pinpoint effective treatments more quickly.The findings are featured online in the journal Genome Research.Emerging sequencing technologies have revolutionized the collection of genomic data for bioforensics, biosurveillance and for use in clinical settings. However, new approaches are being developed to analyze these large volumes of genetic data. Principal investigator Evan Johnson, PhD, assistant professor of medicine at BUSM, and Keith Crandall, PhD, director of the Computational Biology Institute at GWU, have created a statistical framework called Pathoscope to identify pathogenic genetic sequences from infected tissue samples.This unique approach can accurately discriminate between closely related strains of the same species with little coverage of the pathogenic genome. The method also can determine the complete composition of known pathogenic and benign organisms in a biological sample. No other method can accurately identify multiple species or substrains in such a direct and automatic way. Current methods, such as the standard polymerase chain reaction detection or microscope observation, are often imperfect and time-consuming.”Pathoscope is like completing a complex jigsaw puzzle. Instead of manually assembling the puzzle, which can take days or weeks of tedious effort, we use a statistical algorithm that can determine how the picture should look without actually putting it together,” said Johnson. “Our method can characterize a biological sample faster, more accurately and in a more automated fashion than any other approach out there.”This work will be relevant in a broad range of scenarios. For example, in hospitals, this sequencing method will allow for rapid screening of thousands of infectious pathogens simultaneously, while being sensitive enough to monitor disease outbreaks caused by specific pathogenic strains. Veterinarians can even apply the method in their practices. …

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First child born following embryo screening with new genome analysis technique

July 8, 2013 — The first birth has been achieved following the analysis of embryos using a new genome sequencing technique which promises to revolutionise embryo selection for IVF. The technique, which has never before been applied in the screening of embryos, is reported today at the annual meeting of ESHRE by Dr Dagan Wells of the NIHR Biomedical Research Centre at the University of Oxford, UK.The analysis technique is known as “next generation sequencing,” a powerful method capable of decoding entire genomes. Vast quantities of DNA data are produced from each sample tested, simultaneously revealing information on the inheritance of genetic disorders, chromosome abnormalities and mitochondrial mutations. Next generation sequencing (NGS) is already revolutionising many areas of genetic research and diagnostics, said Dr Wells, and, when applied to the assessment of embryos, will allow the concurrent analysis of serious inherited disorders and lethal chromosome abnormalities. “Next generation sequencing provides an unprecedented insight into the biology of embryos,” said Dr Wells.The identification of an embryo destined to implant in the uterus and form a pregnancy remains the holy grail of IVF. On average, only around 30% of embryos currently selected for transfer actually implant. The reason for this high failure rate is unknown, but the prime suspects are unidentified genetic or chromosomal defects. Several genetic screening methods have been introduced over the past decade, but all have been shown to have drawbacks (and have not realised their potential) when tested in randomised clinical trials. This new NGS technique developed by Dr Wells and colleagues, however, seems to overcome the major drawbacks of current methods:Complete chromosome information can be produced revealing abnormalities often responsible for miscarriage Serious gene defects can be identified at the same time The analysis can be completed rapidly (around 16 hours), thus avoiding the need for embryo freezing while awaiting results The test could greatly reduce the costs of embryo screening, which is currently an expensive add-on to IVF. The study described today was designed to test the accuracy and predictability of NGS in embryo selection. …

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Long-held assumption of gene expression in embryonic stem cells challenged

July 3, 2013 — Whitehead Institute researchers have determined that the transcription factor Nanog, which plays a critical role in the self-renewal of embryonic stem cells, is expressed in a manner similar to other pluripotency markers. This finding contradicts the field’s presumptions about this important gene and its role in the differentiation of embryonic stem cells.A large body of research has reported that Nanog is allelically regulated — that is, only one copy of the gene is expressed at any given time — and fluctuations in its expression are responsible for the differences seen in individual embryonic stem (ES) cells’ predilection to differentiate into more specialized cells. These studies relied on cells that had a genetic marker or reporter inserted in the DNA upstream of the Nanog gene. This latest research, published in this week’s edition of the journal Cell Stem Cell, suggests that results from studies based on this approach could be called into question.To quantify the variations in Nanog expression, Dina Faddah, a graduate student in the lab of Whitehead Institute Founding Member Rudolf Jaenisch, looked at hundreds of individual mouse ES cells with reporters inserted immediately downstream of the Nanog gene. One Nanog allele had a green reporter, while the other had a red reporter, allowing Faddah to determine which of the two alleles was being expressed.After analyzing the results and comparing them to the expression of a “housekeeping” gene and other pluripotency factors, Faddah concluded that, regardless of the cells’ growing environment, most ES cells express both Nanog alleles and the variability of this expression corresponds to that of the other genes.When Faddah tested the established method of inserting a reporter upstream of Nanog, her results reflected the earlier studies’ conclusions. However, when she checked the results with other forms of gene expression analysis, she found that the method was not a faithful indicator of Nanog’s expression.”The way the reporter was inserted into the DNA seems to disrupt the regulation of the alleles, so that when the reporter says Nanog isn’t being expressed, it actually is,” says Faddah.For Jaenisch, this is an instructional tale that should be heeded by all geneticists.”Clearly, the conclusions for this particular gene need to be reconsidered,” says Jaenisch, who is also a professor of biology at MIT. “And it raises the question for other genes. For some genes, there might be similar issues. For other genes, they might be more resistant to this type of disturbances caused by a reporter.”This work is supported Vertex Scholars Program, the National Science Foundation (NSF), Jerome and Florence Brill Fellowship, Croucher and Ludwig Research Fellowship, the National Institutes of Health (NIH) (1 F32 GM099153-01A1, HD 045022 and R37CA084198).

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