SIM imaging resolves endocytosis of SARS-CoV-2 spike RBD in living cells.

It is urgent to understand the infection mechanism of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) for the prevention and treatment of COVID-19. The infection of SARS-CoV-2 starts when the receptor-binding domain (RBD) of viral spike protein binds to angiotensin-converting enzyme 2 (ACE2) of the host cell, but the endocytosis details after this binding are not clear. Here, RBD and ACE2 were genetically coded and labeled with organic dyes to track RBD endocytosis in living cells. The photostable dyes enable long-term structured illumination microscopy (SIM) imaging and to quantify RBD-ACE2 binding (RAB) by the intensity ratio of RBD/ACE2 fluorescence. We resolved RAB endocytosis in living cells, including RBD-ACE2 recognition, cofactor-regulated membrane internalization, RAB-bearing vesicle formation and transport, RAB degradation, and downregulation of ACE2. The RAB was found to activate the RBD internalization. After vesicles were transported and matured within cells, RAB was finally degraded after being taken up by lysosomes. This strategy is a promising tool to understand the infection mechanism of SARS-CoV-2.

Systematic scoping review on moral distress among physicians.

BACKGROUND: Concepts of moral distress (MD) among physicians have evolved and extend beyond the notion of psychological distress caused by being in a situation in which one is constrained from acting on what one knows to be right. With many accounts involving complex personal, professional, legal, ethical and moral issues, we propose a review of current understanding of MD among physicians. METHODS: A systematic evidence-based approach guided systematic scoping review is proposed to map the current concepts of MD among physicians published in PubMed, Embase, PsycINFO, Web of Science, SCOPUS, ERIC and Google Scholar databases. Concurrent and independent thematic and direct content analysis (split approach) was conducted on included articles to enhance the reliability and transparency of the process. The themes and categories identified were combined using the jigsaw perspective to create domains that form the framework of the discussion that follows. RESULTS: A total of 30 156 abstracts were identified, 2473 full-text articles were reviewed and 128 articles were included. The five domains identified were as follows: (1) current concepts, (2) risk factors, (3) impact, (4) tools and (5) interventions. CONCLUSIONS: Initial reviews suggest that MD involves conflicts within a physician's personal beliefs, values and principles (personal constructs) caused by personal, ethical, moral, contextual, professional and sociocultural factors. How these experiences are processed and reflected on and then integrated into the physician's personal constructs impacts their self-concepts of personhood and identity and can result in MD. The ring theory of personhood facilitates an appreciation of how new experiences create dissonance and resonance within personal constructs. These insights allow the forwarding of a new broader concept of MD and a personalised approach to assessing and treating MD. While further studies are required to test these findings, they offer a personalised means of supporting a physician's MD and preventing burn-out.