21st Century Medicine (United States)

Background: Nasopharyngeal microbiota plays a crucial role in maintaining respiratory tract health; however, its composition and changes in time can vary significantly with age. Opportunistic microorganisms commonly present in the nasopharynx are not always associated with disease, necessitating a rational approach to interpreting bacteriological findings. Aim: To examine the composition of nasopharyngeal microbiota in healthy residents of Saint Petersburg. Methods: The study included two groups: children (n = 5) and adults (n = 5). Nasal and throat swabs were collected from all participants every two days over a 10-day period. Samples were cultured on nutrient media, followed by microorganism identification and antibiotic susceptibility testing. Results: Significant differences in microbiota composition were observed between the groups. Opportunistic bacteria (e.g., Haemophilus influenzae, Streptococcus pneumoniae) were more frequently detected in children, whereas adults exhibited a predominance of commensal flora (Corynebacterium spp., Streptococcus viridans). High variability of microbiota in children was noted, reducing the clinical value of single-timepoint bacteriological tests. Conclusion: The findings highlight the importance of a balanced approach to interpreting microbiological data. Clinicians should consider that the presence of opportunistic microorganisms may be transient and not necessarily indicative of active disease. Particular attention should be paid to diagnostics in children, as shifts in microbiota composition may represent a natural process rather than a sign of illness. In this context, it is advisable to consider clinical manifestations alongside laboratory findings to avoid unwarranted antibiotic use and reduce the risk of antimicrobial resistance.

Abstract The current liver organ shortage has pushed the field of liver transplantation to develop new methods to prolong the preservation time of livers from the current clinical standard of static cold storage. Our approach, termed partial freezing, aims to induce a thermodynamically stable frozen state at deeper storage temperatures (−10°C to −15°C) than can be achieved with supercooling, while simultaneously maintaining a sufficient unfrozen fraction to limit dehydration and ice damage. This research first demonstrated that partially frozen glycerol treated rat livers were functionally similar after thawing from either −10 or −15°C with respect to subnormothermic machine perfusion metrics and histology. Next, we assessed the effect of adding either of two ice modulators, antifreeze glycoprotein (AFGP) and a polyvinyl alcohol/polyglycerol combination (X/Z-1000), on the viability and structural integrity of partially frozen rat livers compared to glycerol-only control livers. Results showed that AFGP livers had high levels of ATP and the least edema but suffered from significant endothelial cell damage. X/Z-1000 livers had the highest levels of ATP and energy charge (EC) but also demonstrated endothelial damage and post-thaw edema. Glycerol-only control livers exhibited the least DNA damage on Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining but also had the lowest levels of ATP and EC. Further research is necessary to optimize the ideal ice modulator cocktail for our partial-freezing protocol. Modifications to cryoprotective agent (CPA) combinations, as well as improvements to machine perfusion CPA loading and unloading, can help improve the viability of these partially frozen organs.

SummaryFour principles of cognitive science were used to make systematic revisions in middle school science instructional modules from two kinds of curriculum: one popular textbook series and one popular hands‐on series (two modules each). Schools were randomly assigned to 1 of the 3 arms (cognitive science modifications with professional development, active control with professional development, or business‐as‐usual). Two cohorts of students were followed in each arm for each setting. There were significant benefits of the cognitive science intervention, but the nature of effects varied for the two settings and curricula. For the text‐based curriculum, positive effects of cognitive science modifications were concentrated in classrooms with lower proportions of underrepresented minority students. For the hands‐on curriculum, there were positive effects that were not linked to school composition. Participation in the active control did not significantly improve student learning. Implications for policy and research are discussed.