The interphase nucleus is organized such that genomic segments interact in cis, on the same chromosome, and in trans, between different chromosomes. In Drosophila and other Dipterans, extensive interactions are observed between homologous chromosomes, which can permit enhancers and promoters to communicate in trans. Enhancer action in trans has been observed for a handful of genes in Drosophila, but it is as yet unclear whether this is a general property of all enhancers or specific to a few. Here, we test a collection of well-characterized enhancers for the capacity to act in trans. Specifically, we tested 18 enhancers that are active in either the eye or wing disc of third instar Drosophila larvae and, using two different assays, found evidence that each enhancer can act in trans. However, the degree to which trans-action was supported varied greatly between enhancers. Quantitative analysis of enhancer activity supports a model wherein an enhancer's strength of transcriptional activation is a major determinant of its ability to act in trans, but that additional factors may also contribute to an enhancer's trans-activity. In sum, our data suggest that a capacity to activate a promoter on a paired chromosome is common among Drosophila enhancers.KEYWORDS RMCE; interchromosomal interactions; long-range enhancer; somatic homolog pairing; transvection T HE spatial organization of the interphase eukaryotic genome is characterized by extensive long-distance interactions between distal chromosome regions (Sanyal et al. 2012). Interactions have been identified between sequences on the same chromosome (in cis) or on different chromosomes (in trans) (Lieberman-Aiden et al. 2009;Duan et al. 2010;Sexton et al. 2012;van de Werken et al. 2012;Nagano et al. 2013;Zhang et al. 2013). Many long-distance interactions in cis underlie the activation of specific genes, and in some cases, sequences have been identified that facilitate interactions between a distal enhancer and a specific promoter target (Zhou and Levine 1999;Calhoun et al. 2002;Calhoun and Levine 2003;Lin 2003;Akbari et al. 2008;Fujioka et al. 2009;Majumder et al. 2015). In contrast, the genetic impacts of trans-interactions between chromosomes are less clearly understood. Examples of gene regulation involving interchromosomal associations have been described (Spilianakis et al. 2005;Bacher et al. 2006;Xu et al. 2006;Apostolou and Thanos 2008;Sandhu et al. 2009;Markenscoff-Papadimitriou et al. 2014;Patel et al. 2014), but it remains unclear whether it is common for sequences that regulate gene expression to communicate between different chromosomes when they are physically juxtaposed.In Drosophila melanogaster, extensive trans-interactions are observed between homologous chromosomes in virtually all somatic tissues, a phenomenon known as somatic homolog pairing (reviewed by McKee 2004;Bosco 2012). The close proximity of homologous chromosomes in Drosophila can permit an enhancer to act in trans on a promoter on the paired homolog, a form of pairing-dependent ...

Introduction: Since 2017, students applying to emergency medicine residencies must take the AAMC Standardized Video Interview (SVI) to assess their knowledge of professional behaviors and interpersonal and communication skills. Due to the SVI's novelty, there are not many study tools available to prepare for it, outside of the resources provided by the AAMC. Methods: The SVI Self-Study Guide is a PowerPoint document that learners can use to prepare for the SVI independently. It is intended for fourth-year medical students who are applying to emergency medicine residencies and therefore planning to take the SVI. The guide was distributed via email and assessed with a pre-and postquiz measuring subjective feelings of preparedness as well as testing knowledge of professionalism and interpersonal and communication skills. Results: Eleven students were invited to use the SVI Self-Study Guide, of whom 10 and eight took the pre-and postquiz, respectively. There was a statistically significant increase in learners' self-rated feelings of preparedness to take the SVI (p < .05). Although there was no significant change in the average score on four knowledge-based questions (p = .29), the average score increased from 72.50% to 93.25%. Discussion: Overall, there was a higher improvement in feelings of preparedness to take the SVI than in performance on knowledge-based questions. This suggests that learners benefited the most from practicing using the SVI testing format. The SVI Self-Study Guide can be distributed via email to supplement existing resources in preparing for the SVI.

Introduction: Tranexamic acid (TXA) use in pediatrics to control hemorrhage has gained interest in recent years, but there is limited literature on nebulized TXA especially regarding dosing and adverse effects. Tranexamic acid has anti-fibrinolytic properties via competitive inhibition of plasminogen activation making it a logical approach to promote hemostasis in cases of post-tonsillectomy hemorrhage. Case Report: We describe two cases of post-tonsillectomy hemorrhage managed with nebulized TXA. In both cases, bleeding was stopped after TXA administration. Conclusion: To our knowledge, this is the first case report to describe the use of nebulized TXA without an adjunct pharmacotherapy. Our two cases add additional reportable data on the safety of nebulized TXA and possible effectiveness on post-tonsillectomy hemorrhage.

As the US population ages, there is an expected increase in demand for home health aides (HHAs); therefore, it is important to ensure their occupational well-being. Previous studies have demonstrated associations between negative emotions and musculoskeletal pain. Using survey data collected from 285 HHAs, we characterize the association between affect and musculoskeletal pain. Affect was measured using the Positive and Negative Affect Schedule, while musculoskeletal pain was measured using the Brief Pain Inventory. We found that as positive affect composite score increased, musculoskeletal pain decreased [β = -0.57, t(124) = -7.01, p < .001]. There was no significant association between the negative affect composite score and musculoskeletal pain. However, several individual moods were associated with decreased or increased pain. These data suggest that some moods may buffer against musculoskeletal pain, while others may predispose HHAs to musculoskeletal pain.