A new bloodstream infection test created by UC Irvine researchers can speed up diagnosis times with unprecedented accuracy, allowing physicians to treat patients with potentially deadly ailments more promptly and effectively.

The UCI team, led by Weian Zhao, assistant professor of pharmaceutical sciences, developed a new technology called Integrated Comprehensive Droplet Digital Detection. In as little as 90 minutes, IC 3D can detect bacteria in milliliters of blood with single-cell sensitivity; no cell culture is needed.

“We are extremely excited about this technology because it addresses a long-standing unmet medical need in the field,” Zhao said. “As a platform technology, it may have many applications in detecting extremely low-abundance biomarkers in other areas, such as cancers, HIV and, most notably, Ebola.”

Bloodstream infections are a major cause of illness and death. In particular, infections associated with antimicrobial-resistant pathogens are a growing health problem in the U.S. and worldwide. According to the Centers for Disease Control & Prevention, more than 2 million people a year globally get antibiotic-resistant blood infections, with about 23,000 deaths. The extremely high mortality rate for blood infections is due, in part, to the inability to rapidly diagnose and treat patients in the early stages.

Recent molecular diagnosis methods, including polymerase chain reaction, can reduce the assay time to hours but are often not sensitive enough to detect bacteria that occur at low concentrations in blood, as is common in patients with blood infections.

The IC 3D technology differs from other diagnostic techniques in that it converts blood samples directly into billions of very small droplets. Fluorescent DNA sensor solution infused into the droplets detects those with bacterial markers, lighting them up with an intense fluorescent signal. Zhao said that separating the samples into so many small drops minimizes the interference of other components in blood, making it possible to directly detect target bacteria without the purification typically required in conventional assays.

To identify bacteria-containing droplets among billions of others in a timely fashion, the team incorporated a three-dimensional particle counter developed by UCI biomedical engineer Enrico Gratton and his colleagues that tags fluorescent particles within several minutes.

“The IC 3D instrument is designed to read a large volume in each measurement, to speed up diagnosis,” Gratton said. “Importantly, using this technique, we can detect a positive hit with very high confidence.” University of California, Irvine

Beckman Coulter Diagnostics has received 510(k) clearance from the U.S. Food and Drug Administration (FDA) for the Access 25(OH) Vitamin D Total assay. Offering state-of-the-art performance, the new assay is an important addition to the company’s bone metabolism assay menu and is available for use on its Access 2 and UniCel DxI series of immunoassay systems.  “FDA clearance of our 25(OH) Vitamin D Total assay allows us to provide laboratories with the tools needed to confidently diagnose and manage vitamin D deficiency-related diseases,” said Arnd Kaldowski, president, Beckman Coulter Diagnostics. “The new assay delivers increased accuracy in patient results through traceability to the gold standard 25(OH) vitamin D reference measurement procedure (RMP) from Ghent University and equimolar detection of 25(OH) vitamin D2 and 25(OH) vitamin D3.”  The Ghent RMP is the reference procedure utilized by the Vitamin D Standardization Program (VDSP), an international collaboration established by the Office of Dietary Supplements at the National Institutes of Health, with the goal of promoting standardized laboratory measurements of 25(OH) vitamin D around the world.  The new assay also provides excellent stability, greater ease-of-use and convenient storage through innovative new packaging designed to prevent light-induced reagent degradation.

www.beckmancoulter.com

A team of researchers led by a Wayne State University School of Medicine associate professor of obstetrics and gynaecology has published findings that provide novel insight into the cause of preeclampsia, the leading cause of maternal and infant death worldwide, a discovery that could lead to the development of new therapeutic treatments.

“Preeclampsia is a leading cause of maternal and foetal morbidity and mortality worldwide, yet its pathogenesis is still poorly understood,” Dr. Nayak said. “Many studies have suggested that elevated circulating levels of sFlt1 (a tyrosine kinase protein that disables proteins essential to blood vessel growth) contribute to the maternal symptoms of vascular dysfunction that characterize preeclampsia, but the molecular underpinnings of sFlt1 upregulation in preeclampsia have so far been elusive. Our manuscript describes the novel, field-changing finding that vascular endothelial growth factor, or VEGF, of maternal origin can stimulate soluble sFlt1 production by the placenta and that this signalling is involved in the cause of preeclampsia.”

Preeclampsia is a sudden increase in blood pressure after the 20th week of pregnancy. Indicated by a sudden increase in blood pressure and protein in the urine, preeclampsia warning signs, in addition to elevated blood pressure, can include headaches, swelling in the face and hands, blurred vision, chest pain and shortness of breath. While the condition can manifest within a few hours, some women report few or no symptoms.

The condition is responsible for 76,000 maternal deaths and more than 500,000 infant deaths every year, according to estimates from the Preeclampsia Foundation. It can affect the liver, kidney and brain. Some mothers develop seizures (eclampsia) and suffer intracranial haemorrhage, the main cause of death in those who develop the disorder. Some women develop blindness. The babies of preeclamptic mothers are affected by the condition and may develop intrauterine growth restriction or die in utero.

While VEGF is essential for normal embryonic development, Dr. Nayak said, his team’s research has demonstrated that even mild elevation of VEGF levels during early pregnancy can cause severe placental vascular damage and embryonic lethality. The results show that modest increases in VEGF could also be a primary trigger for elevation of placental sFlt1 expression, leading to preeclampsia.

Furthermore,  the findings indicate that sFLT1 plays an essential role in maintaining vascular integrity in the placenta in later stages of pregnancy and suggest that overproduction of sFlt1 in preeclampsia, although damaging to the mother, serves a critical protective function for the placenta and foetus by “sequestering” excess maternal VEGF.

According to the Preeclampsia Foundation, the condition, also known as toxemia or pregnancy-induced hypertension, affects 5 percent to 8 percent of pregnancies. Left untreated or undetected, preeclampsia can rapidly lead to eclampsia, one of the top five causes of maternal death and infant illness and death. Approximately 13 percent of all maternal deaths worldwide – the death of a mother every 12 minutes – have been attributed to eclampsia. The foundation reports that preeclampsia is responsible for nearly 18 percent of all maternal deaths in the United States. Wayne State University School of Medicine

Using next generation gene sequencing techniques, cancer researchers at UT Southwestern Medical Center have identified more than 3,000 new mutations involved in certain kidney cancers, findings that help explain the diversity of cancer behaviours.

 “These studies, which were performed in collaboration with Genentech Inc., identify novel therapeutic targets and suggest that predisposition to kidney cancer across species may be explained, at least in part, by the location of tumour suppressor genes with respect to one another in the genome,” said Dr. James Brugarolas, Associate Professor of Internal Medicine and Developmental Biology, who leads UT Southwestern’s Kidney Cancer Program at the Harold C. Simmons Cancer Center.

More than 250,000 individuals worldwide are diagnosed with kidney cancer every year, with lifetime risk of kidney cancer in the US estimated at 1.6 percent. Most kidney tumours are renal cell carcinomas, which when metastatic remain largely incurable.

Researchers with UT Southwestern’s Kidney Cancer Program had previously identified a critical gene called BAP1 that is intimately tied to kidney cancer formation. Their latest research shows how BAP1 interacts with a second gene, VHL, to transform a normal kidney cell into a cancer cell, which in part appears to be based on the two gene’s close proximity in humans, said Dr. Brugarolas, a Virginia Murchison Linthicum Endowed Scholar in Medical Research.

The newest findings suggest that the transformation begins with a mutation in one of the two copies of VHL, which is the most frequently mutated gene in the most common form of kidney cancer, clear cell type, which accounts for about 75 percent of kidney cancers. The VHL mutation is followed by a loss of the corresponding chromosome arm containing the second copy of VHL, as well as several other genes including PBRM1 and BAP1. This step eliminates the remaining copy of VHL and along with it, one of the two copies of PBRM1 and BAP1, two important genes that protect the kidney from cancer development. The subsequent mutation of the remaining copy of BAP1 leads to aggressive tumours, whereas mutation of the remaining copy of PBRM1 induces less aggressive tumours, said Dr. Payal Kapur, a key investigator of both studies who is an Associate Professor of Pathology and Urology, and the Pathology co-Leader of the Kidney Cancer Program.

This model also explains why humans born with a mutation in VHL have a high likelihood of developing kidney cancer during their life time. In these individuals, all kidney cells are already deficient for one VHL copy and a single deletion eliminates the second copy, along with a copy of BAP1 and PBRM1. In contrast, in other animals, these three genes are located on different chromosomes and thus more mutational events are required for their inactivation than in humans. Consistent with this notion, when UT Southwestern researchers mutated VHL and BAP1 together, kidney cancer resulted in animals.

In a second collaborative study with Genentech Inc., published in Nature Genetics, investigators implicated several genes for the first time in non-clear cell kidney cancer, a less common type that accounts for about 25 percent of kidney cancers. Researchers identified a gene signature that can help differentiate subtypes of non-clear cell tumours to better define their behaviour. Specifically, the researchers characterized alterations from 167 human primary non-clear cell renal cell carcinomas, identifying 16  significantly mutated genes in non-clear cell kidney cancer that may pave the way for the development of novel therapies. The research team also identified a five-gene set that enabled molecular classifications of tumour subtypes, along with a potential therapeutic role for BIRC7 inhibitors for future study.     UT Southwestern Medical Center

Despite a strong suspected link between genetics and asthma, commonly found genetic mutations account for only a small part of the risk for developing the disease — a problem known as missing heritability.

Rare and low frequency genetic mutations have been thought to explain missing heritability, but it appears they are unlikely to play a major role, according to a new study led by scientists from the University of Chicago. Analysing the coding regions of genomes of more than 11,000 individuals, they identified mutations in just three genes that were associated with asthma risk. Each was associated with risk in specific ethnicities.

‘Previous studies have likely overestimated the heritability of asthma,’ said study senior author Carole Ober, PhD, Blum-Riese Professor and chair of the Department of Human Genetics at the University of Chicago. ‘This could be because those estimates are based on correlations between family members that share environment as well as genes, which could inflate the heritability. Gene-environment interactions are not considered in these large scale association studies, and we know that these are particularly important in establishing individual risks for asthma.’

Asthma affects more than 25 million adults and children of all ages and ethnicities in the US. Due to the widespread nature of the disease, most studies of its genetic underpinnings have focused on commonly occurring mutations, referred to as genetic variants. However, while numerous such variants have been identified, they are able to account for only a small proportion of the risk for inheriting or developing asthma. Rare mutations, found in less than five percent of the population, have been hypothesized to explain this disparity.

Graduate student Catherine Igartua led the analysis under the supervision of co-senior author Dan Nicolae, PhD, Professor in the Departments of Medicine, Statistics and Human Genetics. She evaluated nearly 33,000 rare or low frequency mutations in more than 11,000 individuals of a variety of ethnicities representing European, African and Latino backgrounds. She analysed mutations jointly across subjects, using a technique that allowed them to study mutations common in one ethnicity, but rare in others.

Only mutations in the genes GRASP, GSDMB and MTHFR showed a statistical link to asthma risk. Mutations in the first two genes were found primarily in Latino individuals, and mutations in the last gene in those with African ancestry. These genes, involved in protein scaffolding, apoptosis regulation and vitamin B9 metabolism respectively, have as yet unknown roles in asthma. The rarity and ethnic-specificity of these genes is insufficient to account for the widespread prevalence of asthma.

Although rare mutations might not contribute much to population asthma risk, these genes still have the potential to serve as targets for therapeutic development. Ober points to the discovery of rare mutations in the LDL receptor that eventually led to the development of statins to treat high cholesterol. She also notes that it is possible, but unlikely, that there are mutations with large effects on asthma risk outside of their screen as it looked at approximate 60 percent of mutations in coding regions of the genome.

‘It was assumed that there would be rare mutations with larger effect sizes than the common variants we have been studying,’ Ober said. ‘Surprisingly, we found that low frequency mutations explain only a very small amount of asthma risk.’ The University of Chicago Medicine