When it comes to needles and drawing blood, most patients agree that bigger is not better. But in the first study of its kind, Rice University bioengineers have found results from a single drop of blood are highly variable, and as many as six to nine drops must be combined to achieve consistent results.

The study examines the variation between blood drops drawn from a single finger-prick. The results suggest that health care professionals must take care to avoid skewed results as they design new protocols and technologies that rely on finger-prick blood.

“We began looking at this after we got some surprising results from our controls in an earlier study,” said lead investigator Rebecca Richards-Kortum, Rice’s Malcolm Gillis University Professor and director of Rice 360°: Institute for Global Health Technologies. “Students in my lab are developing novel, low-cost platforms for anaemia, platelet and white blood cell testing in low-resource settings, and one of my students, Meaghan Bond, noticed there was wide variation in some of the benchmark tests that she was performing on hospital-grade blood analysers.”

The benchmark controls are used to gauge the accuracy of test results from the new technology under study, so the variation among the control data was a sign that something was amiss. What wasn’t immediately clear was whether the readings resulted from a problem with the current experiments or actual variations in the amount of haemoglobin, platelets and white blood cells (WBC) in the different drops of blood.

Richards-Kortum and Bond designed a simple protocol to test whether there was actual variation, and if so, how much. They drew six successive 20-microliter droplets of blood from 11 donors. As an additional test to determine whether minimum droplet size might also affect the results, they drew 10 successive 10-microliter droplets from seven additional donors.

All droplets were drawn from the same finger-prick, and the researchers followed best practices in obtaining the droplets; the first drop was wiped away to remove contamination from disinfectants, and the finger was not squeezed or “milked,” which can lead to inaccurate results. For experimental controls, they use venipuncture, the standard of care in most hospitals, to draw tubes of blood from an arm vein.

Each 20-microliter droplet was analysed with a hospital-grade blood analyser for haemoglobin concentration, total WBC count, platelet count and three-part WBC differential, a test that measures the ratio of different types of white blood cells, including lymphocytes and granulocytes. Each 10-microliter droplet was tested for haemoglobin concentration with a popular point-of-care blood analyser used in many clinics and blood centres.

“A growing number of clinically important tests are performed using finger-prick blood, and this is especially true in low-resource settings,” Bond said. “It is important to understand how variations in finger-prick blood collection protocols can affect point-of-care test accuracy as well as how results might vary between different kinds of point-of-care tests that use finger-prick blood from the same patient.”

Bond and Richards-Kortum found that haemoglobin content, platelet count and WBC count each varied significantly from drop to drop.

“Some of the differences were surprising,” Bond said. “For example, in some donors, the haemoglobin concentration changed by more than two grams per deciliter in the span of two successive drops of blood.”

Bond and Richards-Kortum found that averaging the results of the droplet tests could produce results that were on par with venous blood tests, but tests on six to nine drops blood were needed to achieve consistent results.

“Finger-prick blood tests can be accurate and they are an important tool for health care providers, particularly in point-of-care and low-resource settings,” Bond said. “Our results show that people need to take care to administer finger-prick tests in a way that produces accurate results because accuracy in these tests is increasingly important for diagnosing conditions like anaemia, infections and sickle-cell anemia, malaria, HIV and other diseases.” Rice University

A group of people with fatal H1N1 flu died after their viral infections triggered a deadly hyperinflammatory disorder in susceptible individuals with gene mutations linked to the overactive immune response, according to a study.

Researchers at Cincinnati Children’s Hospital Medical Center, the University of Alabama Birmingham and Children’s of Alabama led the study. They suggest people with other types of infections and identical gene mutations also may be prone to the disorder, known as reactive HLH (rHLH), or haemophagocytic lymphohistiocytosis.

HLH causes the immune system to essentially overwhelm the body with inflammation that attacks vital organs, often leading to death. Study authors raise the possibility of screening children for HLH genes to identify those who may be at risk during a viral infection.

“Viruses that cause robust immune responses may be more likely to trigger rHLH in genetically susceptible people,” said Randy Cron, M.D., Ph.D., a senior investigator on the study and physician in paediatric rheumatology at UAB and Children’s of Alabama. “Prenatal screening for mutations in common HLH-associated genes may find as much as 10 percent of the general population who are at risk for HLH when an inflammation threshold is reached from H1N1 or other infection triggers.”

This study is the first to identify mutations of HLH-associated genes in H1N1 cases where patients had clinical symptoms of rHLH and a related condition called macrophage activation syndrome, or MAS. An outbreak of H1N1 in 2009 turned into a global pandemic. H1N1 has since become part of the viral mix for the annual flu season and preventive vaccine, the authors note. University of Alabama Birmingham

Physicians and others now recognize that seemingly mild, concussion-type head injuries lead to long-term cognitive impairments surprisingly often. A brain protein called SNTF, which rises in the blood after some concussions, signals the type of brain damage that is thought to be the source of these cognitive impairments, according to a study led by researchers from the Perelman School of Medicine at the University of Pennsylvania, and the University of Glasgow, Glasgow, UK.

“The brain protein specifically indicates the presence of nerve fibre damage that we call diffuse axonal injury,” said senior author Douglas H. Smith, MD, director of the Penn Center for Brain Injury and Repair and the Robert A. Groff Professor of Neurosurgery. “Our findings also confirm that even relatively mild, concussion-type brain impacts can cause permanent damage of this kind.”

The results suggest that blood tests for SNTF might one day be used to diagnose diffuse axonal injury and predict cognitive impairment in concussion patients. Penn Medicine

Alex Travis, associate professor at the Baker Institute for Animal Health, co-authored the study that led to the development of a new stroke diagnosis tool.
Minutes count when treating stroke, but current diagnostics take as long as three hours, careful lab work and skilled technicians to arrive at a conclusive diagnosis. Scientists at Cornell’s Baker Institute for Animal Health have developed a device that helps diagnose stroke in less than 10 minutes using a drop of blood barely big enough to moisten your fingertip.

Having demonstrated proof of principle, the technology eventually could be expanded and used in point-of-care testing devices to diagnose other conditions in humans and animals, including traumatic brain injury (concussion), some forms of dementia, and even some types of cancer and heart disease.

The study’s lead author, Roy Cohen, a research scientist at the Baker Institute, says the technology represents the successful pairing of two big goals in medical diagnostics – small size and simplicity, a combination that means testing could be carried out at a patient’s bedside.

“Three-quarters of stroke patients suffer from ischemic stroke – a blockage of a blood vessel in the brain. In those cases, time is of the essence, because there is a good drug available, but for a successful outcome it has to be given within three or four hours after the onset of symptoms,” says Cohen. “By the time someone identifies the symptoms, gets to the hospital and sits in the emergency room, you don’t have much time to obtain the full benefit of this drug.” Enhancing the speed of diagnosis could save many people from suffering lasting effects of ischemic stroke, he says.

To diagnose stroke, a condition in which blood flow to an area of the brain is limited or cut off, the technology will one day detect several bloodborne biomarkers, molecules that appear in the blood when the stroke occurs. The technology uses enzymes attached to nanoparticles to detect the biomarker molecules and convert that detection into light.

To demonstrate the effectiveness of this new approach, the researchers focused on the biomarker neuron-specific enolase (NSE), a substance found in higher concentrations in the blood of victims of stroke and other conditions. By measuring the amount of light produced from various samples, Cohen and his colleagues can determine the concentration of NSE in the sample. At each step of the way, the signal from the NSE is amplified, so even minute quantities give off enough light for detection.

The idea to tether the enzymes, says co-author Alex Travis, associate professor of reproductive biology at the Baker Institute for Animal Health, came from the hardworking enzymes tethered to the shafts of sperm tails. These sperm enzymes efficiently turn sugars into energy that powers the flagellum and moves the sperm along. The fact that they’re attached to the sperm tail instead of floating around in solution enables the enzymes to efficiently pass the substrate along from point to point and get the most “bang for the buck” from a sugar molecule, according to Travis.

Going forward, Travis and his team will collaborate with a private company to develop the stroke-detecting technique for clinical testing and eventually make it available for use in hospitals. But he’s also excited to expand the system to diagnose other conditions.

“This system could be tailored to detect multiple biomarkers,” says Travis. “That’s the strength of the technique. You could assemble a microfluidic card based on this technology that could detect 10 biomarkers in different wells, and the readout would be the same for each one: light.” Using the same detection system for multiple different biomarkers would make for a simple system in a relatively small package, he says. Cornell University

Stress induced cardiomyopathy after cerebral haemorrhage has been shown to increase the risk of further brain damage. These patients can now be identified by a simple blood test, and a possible treatment for stress induced cardiomyopathy has been discovered – a different kind of anaesthesia than that currently being used.

Stress induced cardiomyopathy is a relatively recently discovered disease where part of the heart muscle ceases to function and results in the heart having reduced pumping capacity. Approximately 90 percent of those affected are upper middle-aged women. The onset is similar to a heart attack, with chest pain and difficulty breathing, but stress induced cardiomyopathy follows a different course.

With stress induced heart failure, the heart spontaneously recovers within a few weeks and thus the prognosis has been seen as good; but, new findings show the prognosis to be approximately the same as for acute ischemic heart disease.

In a new thesis from Sahlgrenska Academy, all patients from the region that suffered a specific type of cerebral haemorrhage (subarachnoid haemorrhage) were followed for two years. In conjunction with the haemorrhage, patients experience a strong stress component. Stress induced cardiomyopathy is therefore relatively common (10-20 percent of the patients) following this type of cerebral haemorrhage, which can cause significant brain damage.
“We saw that patients with stress induced cardiomyopathy had an increased risk of further brain damage in the aftermath of a cerebral haemorrhage and had a worse long-term prognosis, even after we made adjustments for other risk factors,” says Jonatan Oras, PhD Student at Sahlgrenska Academy.

In the thesis, two biomarkers were identified that can be used to identify patients who suffer from stress induced heart failure.
“With a blood test, we are now able to quickly identify patients with stress induced heart failure and apply the right measures sooner,” says Jonatan Oras.

In the experimental part of the thesis, an animal model was used with rats to find a possible treatment for stress induced heart failure. It was found that if the animals were anesthetized with a particular anaesthetic (isoflurane), they did not develop heart failure and the heart muscle retained its elasticity and pumping capacity.

“When we used other anaesthetics, including those currently in use in healthcare, we saw no cardioprotective effect. This is the first potential cardioprotective treatment for stress induced cardiomyopathy to be presented,” says Jonatan Oras.

Further studies of this possible treatment for stress induced cardiomyopathy on patients at risk of developing stress induced cardiomyopathy should be conducted,” Jonatan Oras points out. Sahlgrenska Academy