Real-time optical imaging of the hypoxic status in hemangioma endothelial cells during propranolol therapy.

Infantile hemangioma (IH) is the most common microvascular tumor of infancy involving the area of head and neck. One of the most important independent risk factors of IH is the hypoxia microenvironment. Fluorescent chemosensor provides a noninvasive intervention, high spatiotemporal resolution, ultrasensitive response, and real-time feedback approach to reveal the hypoxic status of cells. Our research group developed an ultrasensitive fluorescent chemosensor, HNT-NTR, and investigated the potential ability of imaging the hypoxic status of hemangioma-derived endothelial cells (HemECs). In this study, we successfully visualized the propranolol (PRN) treatment in HemECs using NHT-NTR with "Turn-off" sensing method. This chemosensor exhibited high sensitivity and selectivity for optical imaging of hypoxic status with fast responsiveness, real-time feedback and durable photostability of the fluorescent signal. It was also confirmed that HNT-NTR could monitor nitroreductase in vivo. Paramountly, we expected this chemosensor to offer an available optical method for imaging of the hypoxic status and visualizing the therapeutic status of PRN therapy in IH with the hypoxia-imaging capability.

Impact of vaccination on the COVID-19 pandemic in U.S. states.

Governments worldwide are implementing mass vaccination programs in an effort to end the novel coronavirus (COVID-19) pandemic. Here, we evaluated the effectiveness of the COVID-19 vaccination program in its early stage and predicted the path to herd immunity in the U.S. By early March 2021, we estimated that vaccination reduced the total number of new cases by 4.4 million (from 33.0 to 28.6 million), prevented approximately 0.12 million hospitalizations (from 0.89 to 0.78 million), and decreased the population infection rate by 1.34 percentage points (from 10.10 to 8.76%). We built a Susceptible-Infected-Recovered (SIR) model with vaccination to predict herd immunity, following the trends from the early-stage vaccination program. Herd immunity could be achieved earlier with a faster vaccination pace, lower vaccine hesitancy, and higher vaccine effectiveness. The Delta variant has substantially postponed the predicted herd immunity date, through a combination of reduced vaccine effectiveness, lowered recovery rate, and increased infection and death rates. These findings improve our understanding of the COVID-19 vaccination and can inform future public health policies.