Chest CT bests assays in diagnosing COVID-19
In a newly published study, chest CT proved more effective than lab analysis in diagnosing the 2019 novel coronavirus, COVID-19. Researchers at Tongji Hospital in Wuhan, China, the province where current outbreak originated, tested 1,014 patients using both chest CT and reverse-transcription polymerase chain reaction (RT-PCR) between Jan. 6 and Feb. 6, 2020. Using RT-PCR as the reference standard, the team assessed chest CT’s performance in diagnosing COVID-19. For patients with multiple RT-PCR tests, the changing results of RT-PCR assays was also assessed in relation to repeated CT scans. When the results were analyzed, 601 patients (59%) had positive RT-PCR results for COVID-19, and 888 (88%) tested positive with chest CT. The sensitivity of chest CT imaging for COVID-19 was 97%. In patients with negative RT-PCR results but positive chest CTs, 48% were deemed highly probable cases, 33% of whom underwent comprehensive evaluation. Among patients undergoing serial RT-PCR assays and CT scans, 60% to 93% received an initial positive chest CT for COVID-19 before the initial positive RT-PCR result. Moreover, 42% of patients showed improvement in follow-up CT imaging before getting a negative RT-PCR result. The team noted several limitations to the study, including the use of RT-PCR assays with a relatively low positive rate as the reference, which could cause the sensitivity of chest CT for COVID-19 to be overestimated. Still, they concluded, “our data and analysis suggest that chest CT should be considered for the COVID-19 screening, comprehensive evaluation, and following-up, especially in endemic areas with high pre-test probability for disease.” Their work was published online Feb. 26, 2020, in the journal Radiology.
Sweat sensor keeps tabs on stress
Wei Gao, an assistant professor of medical engineering at the California Institute of Technology, and colleagues have developed a wireless sensor that can actively monitor levels of the stress hormone cortisol in near-real time. In a pilot study, the mass-producible graphene sensor array noninvasively showed a strong correlation between sweat and circulating cortisol and promptly detected changes in sweat cortisol in response to acute stressors. The study also demonstrated, “for the first time, the diurnal cycle and stress-response profile of sweat cortisol, revealing the potential of dynamic stress monitoring enabled by this Mhealth sensing system,” the authors wrote. “We believe that this platform could contribute to fast, reliable, and decentralized healthcare vigilance at the metabolic level, thus providing an accurate snapshot of our physical, mental, and behavioral changes.” Their work appeared Feb. 26, 2020, in the journal Matter.
Oligodendrocyte-neural connections not just about myelin
Scientists at Technical University Munich have used a combination of sequencing and imaging to demonstrate that the precursors of oligodendrocytes, best known as the cells that make the myelin sheath, could be divided into functional subgroups. Previous work had established that there are subtypes of oligodendrocyte precursor cells (OPCs) running different gene expression programs, but whether individual cells could switch between those programs was not clear. In their experiments, the team showed that OPCs could form two subgroups. One type of cell showed high levels of calcium signaling, and rarely differentiated into myelin-forming cells even when it came into contact with axons, which triggers the formation of myelin. However, such OPCs did form extensive synaptic connections with neurons. The team’s results showed that “a significant proportion of OPCs are not directly involved in generating new myelin,” and that the cells forming the most extensive connections with neurons were not the ones forming myelin, leaving the function of the connections unresolved for now. The authors wrote that “this question remains to be addressed in future studies.” Their work appeared in the Feb. 17, 2020, issue of Nature Neuroscience.
Sharper look yields new potential kinase target in ovarian cancer
Researchers at Fox Chase Cancer Center have identified a so-far-untargeted kinase that was repeatedly seen as part of a “kinase signature” in high-grade serous ovarian cancer. Ovarian cancer is among the deadliest tumors, and targeted options exist only for the minority of patients with BRCA mutations, prompting the authors to search for untargeted kinases via enrichment strategies. They identified a “signature consisting of established HGSOC driver kinases, as well as several kinases previously unexplored” in ovarian cancer. One of those kinases was MRCKA, also known as CDC42BPA, which was overexpressed in about a quarter of ovarian cancer samples the team looked at. They showed that loss-of-function of the kinase, as well as inhibition with BDP9066 “decreased cell proliferation and spheroid formation and induced apoptosis” in cell culture. Their results appeared in the Feb. 18, 2020, issue of Science Signaling.