Design and Synthesis of an Activatable Photoacoustic Probe for Hypochlorous Acid.

Photoacoustic (PA) imaging is a novel imaging modality that combines the high contrast of optical imaging and the deep tissue penetration of ultrasound. PA imaging contrast agents targeting various biological phenomena have been reported, but the development of activatable PA probes, which show a PA signal only in the presence of target molecules, remains challenging in spite of their potential usefulness for real-time PA imaging of specific biomolecules in vivo. To establish a simple design strategy for activatable PA probes, we first designed and synthesized a silicon-rhodamine based near-infrared nonfluorescent dye, wsSiNQ660 (water-soluble SiNQ660), as a scaffold and demonstrated that it offers a high conversion efficiency from light to ultrasound compared to typical near-infrared fluorescent dyes. Importantly, absorption off/on strategies previously established for rhodamine-based fluorescent probes are also applicable to this nonfluorescent dye scaffold. We validated this approach by synthesizing an activatable PA probe for hypochlorous acid (HOCl) and confirmed that it enables three-dimensional imaging of HOCl in mouse subcutis.

Pneumococcal meningitis in a patient with severe COVID-19 on dexamethasone and tocilizumab: A case report.

Although various therapeutic agents have been tried for coronavirus disease-2019 (COVID-19) and evidence has accumulated, the risk of secondary infection is increased by underlying disease and immunosuppressive drugs. We report a case of pneumococcal meningitis in a patient with severe COVID-19 who was receiving dexamethasone and tocilizumab. The patient's symptoms improved with appropriate diagnosis and antimicrobial therapy, and she fortunately returned to society without any neurological sequelae of meningitis.