ABSTRACT
Vaccines are considered the best protective means against coronavirus infection. There is increasing interest in reporting the side effects of vaccines, especially for individuals younger than 18 years old. Accordingly, this analytical cohort study aims to report on the side effects of adult and young individuals who received vaccination within 24 h, 72 h, 5 days, and 1 week through the entire course of vaccination (ECoV). A validated online survey was used to collect information. In total, 1069 individuals were completely followed. Most individuals received the Pfizer vaccine (59.6%). Most individuals had received two doses (69.4%). Very strong and statistically significant associations with side effects (p < 0.05, Phi (Φ) > 0.25) throughout the ECoV were reported for the type of vaccine and female gender. Non-smokers reported weak statistically significant associations. Fatigue and localized pain were the most commonly reported side effect, with onset within 24 h and duration of less than 72 h. The prevalence of reported side effects was statistically significantly higher among young individuals (<18 years old) than among adults (X2 (1) =7.6, p = 0.006. Phi φ = 0.11).
ABSTRACT
Although the adult mammalian heart is incapable of meaningful functional recovery following substantial cardiomyocyte loss, it is now clear that modest cardiomyocyte turnover occurs in adult mouse and human hearts, mediated primarily by proliferation of pre-existing cardiomyocytes. However, fate mapping of these cycling cardiomyocytes has not been possible thus far owing to the lack of identifiable genetic markers. In several organs, stem or progenitor cells reside in relatively hypoxic microenvironments where the stabilization of the hypoxia-inducible factor 1 alpha (Hif-1α) subunit is critical for their maintenance and function. Here we report fate mapping of hypoxic cells and their progenies by generating a transgenic mouse expressing a chimaeric protein in which the oxygen-dependent degradation (ODD) domain of Hif-1α is fused to the tamoxifen-inducible CreERT2 recombinase. In mice bearing the creERT2-ODD transgene driven by either the ubiquitous CAG promoter or the cardiomyocyte-specific α myosin heavy chain promoter, we identify a rare population of hypoxic cardiomyocytes that display characteristics of proliferative neonatal cardiomyocytes, such as smaller size, mononucleation and lower oxidative DNA damage. Notably, these hypoxic cardiomyocytes contributed widely to new cardiomyocyte formation in the adult heart. These results indicate that hypoxia signalling is an important hallmark of cycling cardiomyocytes, and suggest that hypoxia fate mapping can be a powerful tool for identifying cycling cells in adult mammals.
