Keeping you up to date on recent headlines in diagnostics

Researchers develop technique to quickly diagnose pneumonia . . . University of Georgia (UGA; Athens, Georgia) researchers have developed a technique that can diagnose a common type of pneumonia within minutes, potentially replacing existing tests that can take several days for results. The researchers, whose findings are detailed online in the journal PLoS ONE, detected Mycoplasma pneumoniae, which causes atypical or “walking pneumonia,“ in true clinical samples with over 97% accuracy using a recently-developed nanotechnology-based platform. “If you can make a positive identification from a 10-minute test, then appropriate antibiotics can be prescribed, limiting both the consequences in that patient and the likelihood that it will spread to others,“ said lead-author Duncan Krause, a professor in the department of microbiology in the UGA Franklin College of Arts and Sciences. Krause and his colleagues built upon an existing technology called surface-enhanced Raman spectroscopy, which works by detecting spectral signatures of a near-infrared laser as it scatters off a biological specimen. They were able to enhance the Raman signal by using silver nanorod arrays to detect the tiny bacteria in throat swab specimens. Krause, who also directs the interdisciplinary UGA Faculty of Infectious Diseases, compared the nanorod array developed by collaborator Yiping Zhao, director of the UGA Nanoscale Science and Engineering Center, to a brush with densely packed bristles, where each of the tiny silver rods extends out at a specific angle. The sample, such as bacteria from a throat swab, penetrates among the bristles, where the spectral signature produced by the laser is amplified and then analyzed by a computer program. Krause noted that infections due to M. pneumoniae are very common yet difficult to diagnose. The bacterium is a major cause of respiratory disease in humans and the leading cause of pneumonia in older children and young adults. “Walking pneumonia feels like a bad chest cold that will not go away,“ he explained. “It can persist for weeks and even months and can cause permanent damage to the lungs if not diagnosed promptly. A delay in diagnosis extends the likelihood for complications as well as continued transmission of the infection to others.“ Krause said the device can be reduced to a size that could fit in a briefcase, although their testing is currently done only in a laboratory setting. “Our hope is that when we begin to explore the capabilities of this technology, it can be applied in point-of-care testing,“ he added. “Then the impact becomes truly significant.“ Krause hopes the combined efforts of the research specialists in nanotechnology and infectious disease will eventually be able to determine if the technique is effective in detecting other pathogens in clinical samples. “We need to do a thorough job with mycoplasmas first,“ said Krause. “Then we can go to other clinical samples and ask the same questions with other infectious agents.“

Troponin Assay, nanotechnology provide clues to heart failure . . . Today, heart failure is by far the single biggest reason for acute hospital admission. Around 30 million people in Europe have heart failure and its incidence is still increasing: more cases are being identified, more people are living to an old age, and more are surviving a heart attack but with damage to the heart muscle. Yet traditional risk-factor prediction models have only limited accuracy in this population to identify those at highest risk for worsening outcomes. So far, those risk prediction models have relied on measurements of a biomarker known as pro-B-type natriuretic peptide (BNP) for prognostic information, but studies have provided inconsistent and often inaccurate results. Measurements of troponin have been previously used in some types of cardiovascular disease, but the standard assays were not sufficiently sensitive to detect relevant changes in most heart failure patients. Now, the introduction of highly sensitive troponin assays has improved accuracy and allowed the detection of even small concentration changes. This latest study assessed the prognostic value of the new high-sensitive assay with nanotechnology (ie, within the nanogram per liter range) in patients admitted to hospital with heart failure. The investigation, part of the Veteran Affairs Effects of Therapy study, was performed at the San Diego Veteran Affairs Medical Center in California in which 144 patients with acute heart failure were followed from admission to 90 days post-discharge. Troponin I and BNP levels were checked on admission, discharge, and up to four consecutive days during hospitalization. Thirty-eight of the 144 patients reached the study's primary endpoint of mortality or heart failure-related readmission and 22 patients had died by 90 days. Using the new high sensitive assay, troponin measurements could be quantified in more than 99% of serum samples taken from all patients in the study. Analysis showed that levels in the higher quartile ranges (even at these small nanogram levels) were significantly associated with increased risk of mortality and readmission; patients with increasing levels during treatment also had higher mortality rates than those with stable or decreasing levels. The associations with troponin were statistically significant, while those with BNP were not.

Docs develop womb cancer test . . . Doctors have developed a test that can detect womb cancer months before any symptoms. The news is based on research in 37,000 postmenopausal women. It found that an ultrasound technique called transvaginal ultrasound (TVS) can detect about 80% of cases of endometrial cancer (cancer of the womb lining) before symptoms appear. This well-conducted research was the first large study to look at the accuracy of TVS for endometrial cancer. It found that TVS, which measures the thickness of the womb lining (endometrium), had a relatively high accuracy in predicting cases of endometrial cancer and ruling out the presence of cancer. However, the accuracy of the test varied depending on the endometrial thickness that was considered abnormal, as well as risk factors such as bleeding and family history of the disease. Importantly, this study did not look at whether screening led to improved survival rates from the disease. In addition, the potential benefits of screening need to outweigh possible problems, such as false diagnoses and unnecessary treatment. Further research is now needed to identify specific groups that TVS womb screening would clearly benefit.

Drexel researchers develop cell probe to identify diseases in early stage . . .Artist renderings of a nano-needle poking a single cell have become the symbol of nanotechnology, surfacing on covers of magazines and books for about a decade but actual nano-needles able to interrogate small cells without causing cellular damage have not become reality until recently. A Drexel University (Philadelphia) team of engineers, scientists and biologists have developed a carbon nanotube-based device for probing single living cells without damaging them. This technique will allow experts to identify diseases in their early stage and advance drug discovery. The research led by. Yury Gogotsi, professor of materials science and engineering and director of the A.J. Drexel Nanotechnology Institute, and Gary Friedman, professor of electrical engineering, uses the nanotube-based device, known as a cellular endoscope, to evaluate cells about a thousand times smaller than a human hair. The cellular endoscope interrogates the intracellular environment of living cells, delivers fluorescent quantum dots and analyzes molecules inside a cell without the cell recognizing the needle's presence. “Drexel's W. M. Keck Institute for Attofluidic Probes now manufactures the smallest endoscopes ever created,“ Gogotsi said. “Endoscopes provide a potentially transformative technology for studying the fundamentals of single living cells and more broadly, for cell biology.“ Cell biologists usually destroy a large number of cells to extract cellular components and biological molecules needed for identifying diseases and analyzing effects of new drugs, or to achieve a better understanding of how the cell functions. Glass pipettes are widely used to inject material into cells. The pipettes cause too much damage to remain within the cell for a long time and are not designed to report information in the form of optical or electrical signals from within the cell. “We had an idea for a minimally invasive cellular probe, the tip of which could remain within the cell for a long time while reporting important information in the form of optical and electrical signals and transferring tiny amounts of material to and from the cell. This probe is similar to an endoscope employed by doctors to perform minimally invasive operations inside human patients, only much smaller“ said Friedman. “A cellular endoscope reported here is a novel, but conceptually simple device,“ said Riju Singhal, a doctoral candidate and author of the article “Multifunctional carbon-nanotube cellular endoscopes“ published in the Nature Nanotechnology journal. “It consists of a single carbon nanotube connected to the tips of larger glass micropipettes that are commonly employed in biological studies, enabling them to become widely used in the near future,“ said Singhal. Michael Schrlau, research assistant professor in Drexel's Material Science and Engineering who directs the research laboratory of the W. M. Keck Institute, said, “We're now building upon the multiple demonstrated functions of cellular endoscopes to help answer elusive cell biological questions. One application of cellular endoscopes being actively pursued is intracellular surface-enhanced Raman spectroscopy with gold-coated endoscopes.“

– Compiled by Omar Ford, MDD