Distinguishing metastatic SLNs in breast cancer
Researchers in China demonstrated a way to more easily distinguish metastatic sentinel lymph nodes (SLNs) and inflamed lymph nodes (LNs) during surgical resection in breast cancer. SLNs are LNs in which a primary tumor first metastasizes, and identifying them is critical to cancer staging and guiding clinical treatment. The team, at the Britton Chance Center and MOE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Wuhan National Laboratory for Optoelectronics–Huazhong University of Science and Technology, used a CD44 and scavenger receptor class B1 dual-targeting hyaluronic acid nanoparticle (5K-HA-HPPS) loaded with the near-infrared fluorescent dye DiR-BOA for SNL imaging in breast cancer patients. The 5K-HA-HPPSs amassed quickly in the SLNs following intradermal injection. “Compared with normal popliteal LNs (N-LNs), there were ~3.2-fold and ~2.4-fold increases in fluorescence intensity in tumor metastatic SLNs (T-MLN) and inflamed LNs (Inf-LN), respectively,” the researchers said. “More importantly, photoacoustic microscopy (PAM) of 5K-HA-HPPS showed a significantly distinct distribution in T-MLN compared with N-LN and Inf-LN,” with signals clustered at the center of T-MLN but on the periphery of N-LN and Inf-LN. The results suggest that combining 5K-HA-HPPS injection with PAM could be a powerful tool for determining metastases in lymph nodes. The study was published online Sept. 16, 2020, in Light: Science & Applications.
MRS method reveals insights into Alzheimer’s disease
Using magnetic resonance spectroscopy (MRS) at 7-Tesla, researchers at the University of Texas at Dallas’ Center for Brainhealth have examine how cells in the brains of people at risk of developing Alzheimer’s disease make and use energy. Their findings could aid in developing tests for earlier detection and treatment of the mind-robbing disease. For the study, the researchers conducted cognitive assessments and 31phosphorus MRS (31P MRS) on 19 people with amnestic mild cognitive impairment (aMCI). Brain energy metabolism (BEM) were measured using three energy indicators: energy reserve, energy consumption and metabolic state along with regulatory cofactors of BEM-intracellular Mg2 and pH. The 31P MRS scan showed 13 peaks with precise quantification of the phosphorus metabolites at ultra-high-field (UHF) magnetic strength 1-Tesla. BEM indices were associated with lower cognitive performance of memory, executive function and attention. The observation of an inverse relationship in the parieto-occipital lobes suggests a link between neuronal energy markers with cognition in aMCI, the team said. Their work demonstrates the ability to accurately measure high-energy phosphate and membrane phospholipid metabolites in a population with varied outcomes using an approach at UHF. “This work offers a novel approach for future work to further elucidate early dementia biomarkers or precursors to the downstream accumulation of amyloid and tau using the combination of MRS-PET imaging modalities in AD,” the team concluded. Their work was published in Aug. 28, 2020 in Frontiers in Aging Neuroscience.
SARS-CoV-2 multiplex assay allows 3x as many patients per run
Researchers at Northwell Health Laboratories and the Donald and Barbara Zucker School of Medicine at Hofstra/Northwell developed a multiplex assay that performs as well as the CDC’s modified assay but can test significantly more patients per run while using less reagents. The multiplex real-time reverse transcription RT-PCR test for the detection of SARS-CoV-2 has primers that amplify a 108 blood pressure (BP) target on the spike surface glycoprotein and a hydrolysis Taqman probe designed to specifically identify SARS-CoV-2. The team evaluated the assay’s limit of detection (LOD) and clinical performance. In the LOD results study, the Northwell Health Laboratories laboratory developed test (LDT) performed equally to the CDC assay, with a final LOD of 1,301 ± 13 genome equivalences per milliliter versus 1,249 ± 14 genome equivalents/ml for the modified CDC assay. A clinical assessment of 279 nasopharyngeal swab samples showed 98.5% positive agreement and 99.3% negative agreement, compared to the CDC test. Importantly, the Northwell Health LDT’s multiplex design enabled 91 patients to be tested per plate, up from 29 on the modified CDC assay. “The design also showed significant advantages over the modified CDC assay, since only one primer and probe Master Mix is required to prepare and dispense per specimen, in contrast to three sets of Master Mix preparation and the use of three wells for each patient specimen by then modified CDC assay,” the researchers wrote. The multiplex RT-PCR test can be used both to diagnose SARS-CoV-2 and for epidemiological surveillance and clinical management, they said. An additional advantage is that is can be easily established by other laboratories. The assay was developed and validated on the 7500 Fast Dx RT-PCR instrument by Applied Biosystems, a Thermo Fisher Scientific company. Their work was published online Sept. 19, 2020, in The Journal of Molecular Diagnostics.