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Long-term memories are not stored in a stable state but must be flexible and dynamic to maintain relevance in response to new information. Existing memories are thought to be updated through the process of reconsolidation, in which memory retrieval initiates destabilization and updating to incorporate new information. Memory updating is impaired in old age, yet little is known about the mechanisms that go awry. One potential mechanism is the repressive histone deacetylase 3 (HDAC3), which is a powerful negative regulator of memory formation that contributes to age-related impairments in memory formation. Here, we tested whether HDAC3 also contributes to age-related impairments in memory updating using the Objects in Updated Locations (OUL) paradigm. We show that blocking HDAC3 immediately after updating with the pharmacological inhibitor RGFP966 ameliorated age-related impairments in memory updating in 18-m.o. male mice. Surprisingly, we found that post-update HDAC3 inhibition in young (3-m.o.) male mice had no effect on memory updating but instead impaired memory for the original information, suggesting that the original and updated information may compete for expression at test and HDAC3 helps regulate which information is expressed. To test this idea, we next assessed whether HDAC3 inhibition would improve memory updating in young male mice given a weak, subthreshold update. Consistent with our hypothesis, we found that HDAC3 blockade strengthened the subthreshold update without impairing memory for the original information, enabling balanced expression of the original and updated information. Together, this research suggests that HDAC3 may contribute to age-related impairments in memory updating and may regulate the strength of a memory update in young mice, shifting the balance between the original and updated information at test.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by motor neuron loss. Importantly, non-neuronal cell types such as astrocytes also play significant roles in disease pathogenesis. However, mechanisms of astrocyte contribution to ALS remain incompletely understood. Astrocyte involvement suggests that transcellular signaling may play a role in disease. We examined contribution of transmembrane signaling molecule ephrinB2 to ALS pathogenesis, in particular its role in driving motor neuron damage by spinal cord astrocytes. In symptomatic SOD1G93A mice (a well-established ALS model), ephrinB2 expression was dramatically increased in ventral horn astrocytes. Reducing ephrinB2 in the cervical spinal cord ventral horn via viral-mediated shRNA delivery reduced motor neuron loss and preserved respiratory function by maintaining phrenic motor neuron innervation of diaphragm. EphrinB2 expression was also elevated in human ALS spinal cord. These findings implicate ephrinB2 upregulation as both a transcellular signaling mechanism in mutant SOD1-associated ALS and a promising therapeutic target.

Background: The purpose of this study was to evaluate the impact that obesity, smoking, and older age have on 30-day postoperative complications, reoperations, and readmissions of patients undergoing arthroscopic meniscectomy or meniscus repair., Materials and Methods: The American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database was queried to identify meniscus surgeries and operative outcomes between 2008 and 2016. Controlled regression analysis was then performed to evaluate for an association between obesity, age, and smoking and these outcomes., Results: While obesity showed no influence on adverse postoperative complications or reoperations, class I obesity was associated with a lower rate of readmission. Older age, smoking, and comorbidity burden were significant predictors of postoperative complications, reoperations, and/or readmissions. Age 80 years or older was particularly predictive of 30-day complications (odds ratio, 3.5; P <.001) and readmissions (odds ratio, 2.5; P =.004)., Conclusion: Obesity is not a major risk factor for complications when undergoing meniscus surgery, while age older than 70 years predicts negative short-term postoperative outcomes. [ Orthopedics. 20XX;4X(X):XXX-XXX.].

Background: Prenursing students represent the future pipeline of nursing students, yet their perceptions of how COVID-19 affected their experience as prenursing students are unknown., Method: Short-answer data ( n = 289) in US prenursing students were collected in fall 2020. Deductive thematic analysis was applied according to the social determinants of learning (SDOL™) framework., Results: Participants verbalized fears of contracting COVID-19 (physical health) and difficulties with stress and anxiety (psychosocial health). Participants shared pandemic-related financial challenges (economic instability), changes in living situations (physical environment), and the lack of hoped-for social connections (social environment). Many struggled with focus; others confirmed their goals (self-motivation)., Conclusion: The SDOL framework can be utilized by educators to conceptualize the influence of the COVID-19 pandemic on the experiences of online prenursing students and leveraged to develop targeted interventions to improve students' well-being as they apply to nursing programs., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2023 National League for Nursing.)