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diagnostics

Brain Scans Show Early Signs of Autism Spectrum Disorder

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Unhappy baby

Source: Getty Images

For children with autism spectrum disorder (ASD), early diagnosis is critical to allow for possible interventions at a time when the brain is most amenable to change. But that’s been tough to implement for a simple reason: the symptoms of ASD, such as communication difficulties, social deficits, and repetitive behaviors, often do not show up until a child turns 2 or even 3 years old.

Now, an NIH-funded research team has news that may pave the way for earlier detection of ASD. The key is to shift the diagnostic focus from how kids act to how their brains grow. In their brain imaging study, the researchers found that, compared to other children, youngsters with ASD showed unusually rapid brain growth from infancy to age 2. In fact, the growth differences were already evident by their first birthdays, well before autistic behaviors typically emerge.


Snapshots of Life: Virus Hunting with Carbon Nanotubes

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H5N2 trapped in carbon nanotubes

Credit: Penn State University

The purple pods that you see in this scanning electron micrograph are the H5N2 avian flu virus, a costly threat to the poultry and egg industry and, in very rare instances, a health risk for humans. However, these particular pods are unlikely to infect anything because they are trapped in a gray mesh of carbon nanotubes. Made by linking carbon atoms into a cylindrical pattern, such nanotubes are about 10,000 times smaller than width of a human hair.

The nanotubes above have been carefully aligned on a special type of silicon chip called a carbon-nanotube size-tunable-enrichment-microdevice (CNT-STEM). As described recently in Science Advances, this ultrasensitive device is designed to capture viruses rapidly based on their size, not their molecular characteristics [1]. This unique feature enables researchers to detect completely unknown viruses, even when they are present in extremely low numbers. In proof-of-principle studies, CNT-STEM made it possible to collect and detect viruses in a sample at concentrations 100 times lower than with other methods, suggesting the device and its new approach will be helpful in the ongoing hunt for new and emerging viruses, including those that infect people.


Portable System Uses Light to Diagnose Bacterial Infections Faster

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PAD system

Caption: PAD system. Left, four optical testing cubes (blue and white) stacked on the electronic base station (white with initials); right, a smartphone with a special app to receive test results transmitted by the electronic base station.
Credit: Park et al. Sci. Adv. 2016

Every year, hundreds of thousands of Americans acquire potentially life-threatening bacterial infections while in the hospital, nursing home, or other health-care settings [1]. Such infections can be caused by a variety of bacteria, which may respond quite differently to different antibiotics. To match a patient with the most appropriate antibiotic therapy, it’s crucial to determine as quickly as possible what type of bacteria is causing his or her infection. In an effort to improve that process, an NIH-funded team is working to develop a point-of-care system and smartphone app aimed at diagnosing bacterial infections in a faster, more cost-effective manner.

The portable new system, described recently in the journal Science Advances, uses a novel light-based method for detecting telltale genetic sequences from bacteria in bodily fluids, such as blood, urine, or drainage from a skin abscess. Testing takes place within small, optical cubes that, when placed on an electronic base station, deliver test results within a couple of hours via a simple readout sent directly to a smartphone [2]. When the system was tested on clinical samples from a small number of hospitalized patients, researchers found that not only did it diagnose bacterial infections about as accurately and more swiftly than current methods, but it was also cheaper. This new system can potentially also be used to test for the presence of antibiotic-resistant bacteria and contamination of medical devices.


Lyme Disease: Gene Signatures May Catch the Infection Sooner

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Borrelia burgdoferi

Caption: Borrelia burgdorferi. Immunofluorescent antibodies bind to surface proteins on the bacterium that causes Lyme disease, producing fluorescent yellow, red, and green hues.
Credit: National Institute of Allergy and Infectious Diseases

Each year, thousands of Americans are bitten by deer ticks.These tiny ticks, common in and around wooded areas in some parts of the United States, can transmit a bacterium into the bloodstream that causes Lyme disease. Those infected experience fever, headache, stiff necks, body aches, and fatigue. A characteristic circular “target” red rash can mark the site of the tick bite, but isn’t always noticed. In fact, many people don’t realize that they’ve been bitten, and weeks can pass before they see a doctor. By then the infection has spread, sometimes causing additional rashes and/or neurological, cardiac, and rheumatological symptoms that mimic those of other conditions. All of this can make getting the right diagnosis frustrating, especially in areas where Lyme disease is rare.

Even when Lyme disease is suspected early on, the bacterium is unusually slow growing and present at low levels, so it can take a while before blood tests detect antibodies to confirm the condition. By then, knocking out the infection with antibiotics can be more challenging. But research progress continues to be made toward improving the diagnosis of Lyme disease.

An NIH-supported team recently uncovered a unique gene expression pattern in white blood cells from people infected with the Lyme disease-causing bacterium Borrelia burgdorferi [1]. This distinctive early gene signature, which persists after antibiotic treatment, is unique from other viral and bacterial illnesses studies by the team. With further work and validation, the test could one day possibly provide a valuable new tool to help doctors diagnose Lyme disease earlier and help more people get the timely treatment that they need.


Gene Expression Test Aims to Reduce Antibiotic Overuse

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Doctor with ER patient

Caption: Duke physician-scientist Ephraim Tsalik assesses a patient for a respiratory infection.
Credit: Shawn Rocco/Duke Health

Without doubt, antibiotic drugs have saved hundreds of millions of lives from bacterial infections that would have otherwise been fatal. But their inappropriate use has led to the rise of antibiotic-resistant superbugs, which now infect at least 2 million Americans every year and are responsible for thousands of deaths [1]. I’ve just come from the World Economic Forum in Davos, Switzerland, where concerns about antibiotic resistance and overuse was a topic of conversation. In fact, some of the world’s biggest pharmaceutical companies issued a joint declaration at the forum, calling on governments and industry to work together to combat this growing public health threat [2].

Many people who go to the doctor suffering from respiratory symptoms expect to be given a prescription for antibiotics. Not only do such antibiotics often fail to help, they serve to fuel the development of antibiotic-resistant superbugs [3]. That’s because antibiotics are only useful in treating respiratory illnesses caused by bacteria, and have no impact on those caused by viruses (which are frequent in the wintertime). So, I’m pleased to report that a research team, partially supported by NIH, recently made progress toward a simple blood test that analyzes patterns of gene expression to determine if a patient’s respiratory symptoms likely stem from a bacterial infection, viral infection, or no infection at all.

In contrast to standard tests that look for signs of a specific infectious agent—respiratory syncytial virus (RSV) or the influenza virus, for instance—the new strategy casts a wide net that takes into account changes in the patterns of gene expression in the bloodstream, which differ depending on whether a person is fighting off a bacterial or a viral infection. As reported in Science Translational Medicine [4], Geoffrey Ginsburg, Christopher Woods, and Ephraim Tsalik of Duke University’s Center for Applied Genomics and Precision Medicine, Durham, NC, and their colleagues collected blood samples from 273 people who came to the emergency room (ER) with signs of acute respiratory illness. Standard diagnostic tests showed that 70 patients arrived in the ER with bacterial infections and 115 were battling viruses. Another 88 patients had no signs of infection, with symptoms traced instead to other health conditions.


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