The advantage that silver nanoparticles, also called nanosilver, provide over older silver treatments is that their small size allows them to enter the bloodstream directly.

New and Improved Silver Nanoparticles Could Help Hospitals Combat MRSA

Strains of gonorrhea have developed resistance to last-resort antibiotics, according to a recent report by the Centers for Disease Control and Prevention (CDC), making it one of a growing list of diseases that traditional antibiotics may soon be unable to cure. As the age-old war between humans and infectious microbes intensifies, one solution may be a new version of an ancient medical substance: silver.


 But the silver comes in a form that doctors thousands of years ago never would have imagined—nanoparticles. A team of researchers at Nankai University in China has created a
 <a href="http://pubs.acs.org/doi/abs/10.1021/acsami.6b09267">
 silver nanoparticle
 </a>
 designed to be more effective against bacteria in wounds and the bloodstream while being minimally toxic to human cells. The nanoparticle has been tested in rats, and the authors claim that it could be used clinically.

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 While nanoparticles are a recent technology, the antimicrobial properties of silver have been known for thousands of years: the ancient Phoenicians stored liquids in silver vessels to prevent them from spoiling. “That’s why we call forks and knives silverware. You get less sick if you eat with silver,” said Georgios Sotiriou, assistant professor in the department of microbiology, tumor and cell biology at Karolinska Institutet in Sweden. More recently, silver has been used as an antimicrobial in medical applications for decades, such as in wound dressings for burn victims.


 The advantage that silver nanoparticles, also called nanosilver, provide over older silver treatments is that their small size allows them to enter the bloodstream directly and release silver ions at a much higher rate. Silver ions only disperse at a particle’s surface, so the greater the ratio of surface area to volume, the more effective the particle. Nanoparticles, which have no dimension greater than 100 nanometers—roughly one thousandth the width of a human hair—are highly effective.


 However, silver particles have yet to see wide use because they tend to clump together in solution, decreasing their effectiveness. To solve this problem, the team combined silver with a compound known as an alkylated ε-polylysine that they found to be especially effective at preventing clumping. Furthermore, the compound was itself a good antimicrobial agent—polylysines are used as food preservatives in Japan.

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 When combined, the silver and compound worked together to kill more bacteria than either could alone. The addition of the compound was “the key reason making the nanoparticles more effective,” said paper co-author Xinge Zhang, an associate professor at the Nankai University Institute of Polymer Science.


 Silver nanoparticles are effective against even antibiotic-resistant strains of bacteria because they use different mechanisms than traditional antibiotics, Zhang said. The particles can kill bacteria in several ways, such as by anchoring to bacterial cell walls to tear them or by releasing silver ions that penetrate the cell membrane and deactivate important enzymes. That silver nanoparticles kill bacteria in multiple ways at once will likely make it harder for bacteria to develop resistance to them, Sotiriou said.


 The new silver nanoparticle “should be effective against MRSA,” Zhang said, referring to the deadly, highly antibiotic-resistant hospital superbug.


 Still, some concerns about silver nanoparticles remain.


 Though bacterial resistance to silver is not common, it has been found in burn victim wards where silver is used frequently. Because of this, some scientists object to the current widespread use of nanosilver as an antibacterial ingredient in consumer products from hand sanitizers to children’s toys to deodorized socks.


 Silver’s toxicity to humans is another potential concern. The Nankai research team modified the length of one part of their nanoparticle in a way that they claim minimized toxicity—but experts aren’t very concerned about toxicity in the typical medical usage of silver nanoparticles anyway.


 “Silver nanoparticles applied to skin or ingested are not very toxic,” said University of Colorado Boulder assistant professor Marina Vance, who was not affiliated with the study. Vance cautioned that there are still concerns about long-term effects of silver accumulation in people and in the environment. “Introducing antimicrobial products in the wastewater stream may affect the biological process we use to treat wastewater,” Vance said.


 In spite of the concerns, research groups around the world are experimenting to find new applications for silver nanoparticles. If and when the particles will be used in hospitals is hard to know. “The research is still in its early stage,” Zhang said.

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 Photo credit:
 <a href="https://www.flickr.com/photos/105572614@N04/10304285224">
 Sprott Money / Flickr (CC BY 2.0)
 </a>

A new silver nanoparticle could be effective against bacteria—even antibiotic-resistant strains—while being minimally toxic to human cells.

The Venom of This Dangerous Wasp Could Someday Help Treat Anxiety

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 Entomologist Justin Schmidt describes being stung by a
 
 Synoeca
 
 wasp in his sting pain index, a list that ranks insect stings from least to most painful, as “torture. You are chained in the flow of an active volcano.”
 

 It is perhaps counterintuitive, then, that the venom of one
 
 Synoeca
 
 wasp may be beneficial for a person’s mental health. While entomologists like Schmidt have been interested in
 
 Synoeca
 
 wasps for years because of their advanced social structures, few researchers have paid attention to the wasp’s venom—other than as something to avoid. But a researcher team in Brazil
 <a href="http://www.sciencedirect.com/science/article/pii/S0041010116302781">
 has discovered
 </a>
 that the wasp’s venom contains a previously unknown compound that could treat anxiety. The compound worked as effectively as the “gold standard” anti-anxiety drug diazepam when tested in rats, according to the study.
 
<figure class="richtext-image full-width">
<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/synoeca-surinama.width-990_khuhZL9.jpg"/>
<figcaption>This wasp’s venom contains a compound that worked as effectively as the "gold standard" anti-anxiety drug diazepam when tested in rats.
 
 </figcaption>
</figure>

 Márcia Mortari, a professor at the University of Brasília and the team’s lead researcher, said she focused her efforts on anxiety and other neurological diseases and disorders because they were “very prevalent and, unfortunately, there are no efficient treatments for them.” Anxiety disorders affect
 <a href="https://www.nimh.nih.gov/health/statistics/prevalence/any-anxiety-disorder-among-adults.shtml">
 18.1% of U.S. adults
 </a>
 .
 

 The team isolated the potential drug from extracted venom and tested it using an elevated plus maze (EPM), a common test that evaluates anxiety by seeing how much time rats are willing to spend in raised, open spaces. To rats, it’s the nerve-wracking equivalent of walking across a tall bridge without railings. When the team injected rats with the wasp venom compound, the rats became more willing to explore and linger in open spaces.
 

 The EPM “is one of the best tests to measure acute fear” and has been used to test existing anti-anxiety drugs, so it is a good measure of the compound’s efficacy, said Dr. S.M. Korte, an associate professor of pharmacology at Utrecht University in the Netherlands who was unaffiliated with the study.
 

 Venoms contain hundreds of compounds, so finding one that treats a particular disease is “a bit like finding the needle in the haystack,” said Dr. Volker Herzig, a senior research officer at the University of Queensland in Australia who was also not affiliated with the study.
 

 Mortari’s team made their discovery through trial and error. They tested several compounds in rats for both seizure prevention and anti-anxiety effects and made one positive match, Mortari said. The team has also tested wasp venom in search of treatments for Parkinson’s and Alzheimer’s disease and pain relief.
 

 Mortari said her team was the first to try cataloging the therapeutic effects of venom in this particular wasp species, though researchers have been looking to animal venoms for potential pharmaceuticals for decades. Captopril, released in 1981, is used to treat high blood pressure and cardiac failure and was based on Jararaca pit viper snake venom. However, of the millions of compounds from venom that have been catalogued, very few have ever made it into clinical trials, let alone onto pharmacy shelves.
 

 Herzig and Korte were skeptical that the wasp venom compound would ever become a pharmaceutical drug. Mortari agreed that it would not be effective if taken orally because it would not be absorbed well in the digestive system. The team is working on alternative delivery systems, such as a nanoparticle that would carry the compound with it into the bloodstream or transdermal patches that would deliver the drug through the skin.
 

 However, even if Mortari could coax the compound into the bloodstream, Herzig and Korte both expect it would to be too large to pass the blood-brain barrier, and so would not reach the brain. The problem is shared among many potential drugs for CNS disorders, which is one reason why there are so few effective treatments.
 

 Given the obstacles, the compound may not be the next anti-anxiety wonder drug, but it could still “help us better understand the neurobiology of anxiety,” Mortari said. Korte agreed that the research had value regardless of the clinical results, saying, “It is high-risk fundamental research.”
 

 The research is risky in more ways than one, because in order for Mortari’s lab to continue their work, someone will have to collect more wasps to extract venom from. As Schmidt, the entomologist, can confirm, getting too close to
 
 Synoeca
 
 wasps can be a painful endeavor: “Any takers?”
 
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 Photo credit:
 <a href="https://www.flickr.com/photos/lolodoc/4916358830/sizes/l">
 Lauren DEJAULT / Flickr (CC BY-SA 2.0)
 </a>

What Might Genetic Sequencing Mean For Your Future?

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 When most people’s kids have trouble with their teeth, they consult a dentist. When geneticist Heidi Rehm’s daughter had a problem, Rehm decided to get part of her daughter’s genome sequenced.
 

 Rehm learned that the problem went well beyond her daughter’s teeth. Instead, she discovered that her daughter had a rare mutation that put her at risk of developing dilated cardiomyopathy, a disease than can lead to heart failure. The disease is often hereditary, so Rehm got her own genome sequenced, and discovered that she, too, had the same mutation, as did her mother. However, no one could tell Rehm what the genetic results meant: how likely was she to get the disease because she had this one mutation associated with it?
 

 As a genetics expert—Rehm is the clinical director of the Laboratory for Molecular Medicine in Cambridge, Massachusetts—instead of letting the bad news paralyze her, she was motivated to find out more. She started by searching for people with the same mutation to ask how the disease has progressed for them. So far she’s identified a total of nine cases around the world—including herself, her mother, and her daughter.
 

 That’s not much information, but it’s still more than another worried mother in Rehm’s position would have. When most patients get results like Rehm’s, they have no way to know what their genetics mean for their futures. Rehm wants to solve that problem.
 
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<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/gel-electrophoresis_2048x1152.width-990_3JP5Bxr.jpg"/>
<figcaption>Gel electrophoresis, a method for separation of DNA fragments, is shown here in ultraviolet light.
 
 </figcaption>
</figure>

 Genetic sequencing is the predominant tool used in personalized—or precision—medicine, which monitors people’s DNA and biomarkers to improve their healthcare. Precision medicine allows doctors to alert healthy patients to their disease risks and match sick patients to effective treatment plans.
 

 Precision medicine has led to many advances in healthcare. For example, a subset of leukemia patients have a genetic mutation that makes them respond positively to a certain drug, said David Steensma, an oncologist at the Dana-Farber Cancer Institute. If the oncologist knows to screen for that mutation, the patients can be cured. “I have patients [with the mutation] who had been resistant to several other treatments, but now are alive several years later when they wouldn’t have been,” Steensma said.
 

 However, the connection between many genetic mutations and possible diseases remains poorly understood, as was the case with Rehm’s daughter, so different doctors may give patients very different information about their disease risks after looking at the same genetic data. Rehm is involved in several initiatives within the field of precision medicine to standardize and improve genetic research practices and doctor-patient discussions. She helped develop the American College of Medical Genetics and Genomics and the Association for Molecular Pathology guidelines for assessing the disease risk of genetic mutations using a five-tier system that ranges from pathogenic to benign. She’s also working on improving databases in which labs can share their interpretations of which mutations cause diseases.
 

 Building a scientific consensus on which mutations have a high likelihood of causing disease is important because uncertainty can have serious consequences. Dr. Mary Norton, an obstetrician-gynecologist and professor at the University of California, San Francisco, is an expert in prenatal genetic testing and said that the testing often reveals mutations of unknown significance. “You might have to say, ‘We don’t really know. Maybe it’s really bad, maybe it’s nothing. Do you want to terminate your pregnancy?’” Norton said.
 

 Geneticists including Norton stress the importance of patients receiving counseling about what the tests could reveal before getting their genomes sequenced. If not properly counseled beforehand, including about the possibility of uncertain results, some patients may find out information that they wish they could unlearn, Norton said. “Our ability to test has far outstripped our ability to interpret. It’s going to be complicated. We have to be mindful,” Norton said.
 

 When labs interpret a mutation incorrectly, having a procedure in place to revisit the results or make the data public so outside geneticists can catch the error can make a big difference. However, many laboratories that sequence genomes lack detailed procedures for data sharing or reanalysis, according to a survey of current practices published in
 <a href="http://www.nature.com/gim/journal/vaop/ncurrent/full/gim2016152a.html">
 Nature
 </a>
 co-authored by Rehm. Rehm wants all labs to “share and compare” their data results.
 

 “From anecdotes, I knew [genetic interpretation] was being done with very different standards, and inaccurate information was being delivered to patients,” Rehm said. She helped create a system for labs that share their data to identify conflicting interpretations—cases where different labs looked at patients with the same mutations and reached different conclusions about their disease risk. “Now we have targeted efforts to systematically resolve these differences,” Rehm said.
 

 When it comes to interpreting genetic results, “we’re very clumsy at this stuff right now,” said Dr. Michael Snyder, the director of the Stanford Center for Genomics and Personalized Medicine, “but in the future we’ll get good at it.”
 

 Snyder has personal reason to believe in the utility of genetic sequencing: his lab has been monitoring his genome and other biomarkers for seven years. (He gets blood drawn up to 20 times a year.) Rehm calls him the “poster child of self-monitoring.” This testing helped him to discover he was at risk of developing type 2 diabetes shortly before he got the disease. Because the lab caught it early, Snyder has been able to keep his diabetes well managed.
 

 Snyder said that as geneticists gather more data and figure out the significance of mutations, genetic sequencing will change how people think about healthcare. He envisions a future where everyone gets genomic and biomarker checkups. “We generally only see people when they get sick or ill. We rarely put much effort to keep them healthy,” Snyder said. Precision medicine could help people get treatment sooner or keep them from getting sick entirely. Along with catching Snyder’s diabetes, his lab has helped patients find cancer in very early stages, know which cancers to keep an eye out for, and understand how their bodies respond to different diet and exercise choices.
 

 Rong Chen, the director of Clinical Genome Informatics at the Icahn School of Medicine at Mount Sinai, who has worked with Snyder before, said that with Snyder’s and others’ work “collecting this sort of longitudinal data, you’ll be able to change people’s lives.”
 

 However, Chen is not quite as optimistic as Snyder about a bigger role for precision medicine in the near future. There are numerous roadblocks to developing a better knowledge base about how to interpret genetic data, Chen said, including lack of data sharing, issues with data quality, and gathering enough patients—especially from underrepresented populations.
 

 Rehm mentioned another major roadblock: the possibility of bankrupting the healthcare system. “If we unleash genomes on everyone, and a good percentage of people have got things that need to get followed up, I don’t know that our healthcare system can afford to deal with that,” she said. In particular, until doctors know which genetic mutations actually are significant and high risk, the healthcare system would end up paying for a lot of unnecessary follow up.
 

 Yet Rehm is determined to follow up on her family’s rare mutation. She still doesn’t know if it means they will one day get the disease. She says she doesn’t let the finding get to her. “Should I be worried about it? No. Because I can’t change it,” Rehm said. But she continues to track down any information that she can. “Why? Because I want to know what’s in store potentially for me, my daughter, and my mother.”
 
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 Image credit:
 <a href="https://www.flickr.com/photos/qubodup/11585831014/">
 Iwan Gabovitch / Flickr (Public Domain)
 </a>

New System Predicts Flash Droughts Up to Four Months Ahead of Time

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 The 2012 U.S. flash drought that cost the country
 <a href="https://www.nsf.gov/news/news_summ.jsp?cntn_id=190023">
 $30 billion
 </a>
 in economic losses could have been predicted up to four months in advance.
 

 Scientists at the National Center for Atmospheric Research (NCAR) have analyzed soil moisture and snowpack data in the months leading up to the drought and have discovered that they could have been used to make a much earlier
 <a href="http://onlinelibrary.wiley.com/doi/10.1002/2016JD025322/full">
 drought prediction
 </a>
 . If the model can be applied to similar droughts in the future, it could have huge impacts on crop yields, food prices, water management, and perhaps even taxpayers’ wallets.
 

 After the 2012 U.S. drought, taxpayers footed the bill for
 <a href="https://www.nrdc.org/media/2013/130827">
 $17.3 billion
 </a>
 in federally subsidized crop insurance payouts to farmers. Prices for produce and meat shot up in response to low crop yields, with effects lasting several years and—because the U.S. is a major food exporter—affecting the
 <a href="http://www.worldbank.org/en/news/press-release/2012/08/30/severe-droughts-drive-food-prices-higher-threatening-poor">
 entire globe
 </a>
 .
 
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<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/dry-drought_2048x1152.width-990_n5GJwHG.jpg"/>
<figcaption>If droughts could be predicted before planting season, farmers could change their irrigation and planting schedules.
 
 </figcaption>
</figure>

 Current drought forecasting systems cannot predict flash droughts like the 2012 one because these droughts are not preceded by typical indicators, such as large shifts in weather systems that lead to less precipitation. The new model, developed at NCAR, looks to the ground as well as the sky for clues to an upcoming drought.
 

 “We need to understand the land surface conditions in addition to understanding the overlying climate conditions,” said NCAR scientist James Done, co-author of the study.
 

 Case in point, soil moisture affects the exchange of water and heat between the ground and atmosphere, which in turn affects weather patterns and precipitation. Due to that connection, an earlier study found that low soil moisture could be used to predict flash droughts one to two months in advance. NCAR scientist Debasish PaiMazumder, along with Done, wondered if that model could be improved upon.
 

 PaiMazumder, who moved to Boulder, Colorado, in February 2012, months before the drought hit that region hard, recalled being surprised by the mild winter. He wondered if the lack of snow in February could have been related to the drought conditions in the summer. He and Done analyzed decades of data on snowmelt, soil moisture, and drought. They found that low snowmelt in the spring correlated with dry soil later on and could be used to extend the previous drought prediction model to four months lead time.
 

 The research has not been incorporated into active weather forecasting systems yet. The process of turning research results into prediction tools can take around six months, Done said, based off previous experience.
 

 Earlier drought prediction forecasts “will give more time for farmers, ranchers, and water resource managers to prepare for this type of drought,” PaiMazumder said. “Lead time could be important for mitigation strategies.”
 

 During the 2012 drought,
 <a href="http://www.nytimes.com/2012/07/26/business/food-prices-to-rise-in-wake-of-severe-drought.html?_r=2&amp;mtrref=blog.ucsusa.org&amp;mtrref=www.nytimes.com&amp;gwh=81ACEE68FEE2F203C555CBBC6C64115C&amp;gwt=pay">
 88% of U.S. corn crops
 </a>
 were affected. Yield decreased by 50% in the cornbelt, causing corn prices to rise by around 20%, said Gary Schnitkey, a professor at the University of Illinois who researches farm and risk management. If droughts could be predicted before planting season, farmers could change their irrigation and planting schedules, in accordance with drought
 <a href="http://smallfarms.oregonstate.edu/sfn/sp14drought">
 mitigation strategies
 </a>
 . They might plant more drought resistant crops instead of corn, Schnitkey said.
 

 In spite of the new research, Schnitkey was skeptical of the prospect of an accurate long-range drought forecast system, at least in the unpredictable climate of the U.S. cornbelt. “There really isn’t a model that most people believe or that has been proven to be accurate” for predicting weather more than a few weeks in advance, he said. A “false positive” in which farmers cut back on crops or culled cattle in preparation for a drought that never came would be a serious problem, Schnitkey said.
 

 The NCAR team is optimistic that their research can be used to improve existing drought prediction forecasts, but agrees that advanced weather forecasting is challenging and that lots of unknown factors remain. PaiMazumder and Done are already searching for more drought predictors that could be added to the model, as well as for indications of how “flash drought is changing in changing climate,” PaiMazumder said.
 

 The frequency of flash droughts is expected to increase in the coming years, so NCAR scientists are working with a sense of urgency to build better models. “Watch this space,” Done said.
 
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 Photo credit:
 <a href="https://commons.wikimedia.org/wiki/File:Drought-780088.jpg">
 daeron / Wikimedia Commons (CC0 1.0)
 </a>

Greta Friar

Articles

New and Improved Silver Nanoparticles Could Help Hospitals Combat MRSA

The Venom of This Dangerous Wasp Could Someday Help Treat Anxiety

What Might Genetic Sequencing Mean For Your Future?

New System Predicts Flash Droughts Up to Four Months Ahead of Time

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