Fatal SARS-CoV-2 Infection among Children, Japan, January-September 20221.

To determine the characteristics of pediatric patients 0-19 years of age who died after onset of SARS-CoV-2 infection in Japan during January 1-September 30, 2022, we reviewed multiple sources. We identified 62 cases, collected detailed information from medical records and death certificates, and conducted interviews, resulting in 53 patients with detailed information for our study. Among 46 patients with internal causes of death (i.e., not external causes such as trauma), 15% were <1 year of age, 59% had no underlying disease, and 88% eligible for vaccination were unvaccinated. Nonrespiratory symptoms were more common than respiratory symptoms. Out-of-hospital cardiac arrest affected 46% of patients, and time from symptom onset to death was <7 days for 77%. Main suspected causes of death were central nervous system abnormalities (35%) and cardiac abnormalities (20%). We recommend careful follow-up of pediatric patients after SARS-CoV-2 infection during the first week after symptom onset, regardless of underlying diseases.

Imaging of HIF-1-active tumor hypoxia using a protein effectively delivered to and specifically stabilized in HIF-1-active tumor cells.

UNLABELLED: Hypoxia-inducible factor-1 (HIF-1) plays an important role in malignant tumor progression and in the development of resistance to radiotherapy. We designed a novel fusion protein (PTD-ODD-SAV [POS]) consisting of a protein transduction domain (PTD), streptavidin (SAV), and a portion of the oxygen-dependent degradation domain (ODD) of HIF-1alpha that confers the same oxygen-dependent regulation as HIF-1alpha on POS. (3-(123/125)I-iodobenzoyl)norbiotinamide ((123/125)I-IBB) was conjugated to the SAV moiety of POS to synthesize (123/125)I-IBB-labeled POS ((123/125)I-IPOS). The purpose of this study was to evaluate the feasibility of (123)I-IPOS as an imaging probe for HIF-1-active tumor hypoxia. METHODS: After a 24-h incubation of (125)I-IPOS with various tumor cell lines under either normoxic (20% O(2)) or hypoxic (0.1% O(2)) conditions, the intracellular radioactivity was investigated. Then, the biodistribution of (123/125)I-IPOS was examined with tumor-implanted mice, and an in vivo imaging study was performed. The tumoral accumulation of (125)I-IPOS was compared with HIF-1 activity using the mice carrying tumors with the HIF-1-dependent luciferase reporter gene. Furthermore, the intratumoral localization of (125)I-IPOS was examined by the autoradiographic study, and then the same slide was subjected to immunostaining for pimonidazole, which is the hypoxic marker. RESULTS: The ratios of radioactivity in hypoxic cells to that in normoxic cells were more than 2. These results indicate incorporation of (125)I-IPOS into these cells and degradation of (125)I-IPOS by normoxic tumor cells. In the biodistribution study, (125)I-IPOS accumulated in the tumor (1.4 +/- 0.3 percentage injected dose per gram) 24 h after administration. At that time, (125)I-IPOS showed high tumor-to-blood and tumor-to-muscle ratios (5.1 +/- 0.3 and 14.0 +/- 3.9, respectively). The tumors were clearly visualized by in vivo imaging 24 h after (123)I-IPOS injection (tumor-to-muscle ratio was 9.6). The tumoral accumulation of (125)I-IPOS correlated with HIF-1 activity (R = 0.71, P < 0.05), and its intratumoral distribution coincided with the hypoxic regions. CONCLUSION: (123)I-IPOS is a potential probe for the imaging of HIF-1 activity in tumors. Given the role of HIF-1 in tumor biology, its detection may be considered an indicator of aggressive cancer phenotypes.