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Introduction: Clinical use of transthoracic echocardiogram (TTE) in intensive care units (ICU) has dramatically increased without clear guidance on validated assessment indications, appropriateness, and patient value., Methods: A retrospective analysis of consecutive TTEs performed among patients admitted to a tertiary trauma/surgical ICU over 2.5 years was performed. A bivariate analysis and Poisson regression was used to compare patients who received a TTE. Sensitivity analysis was performed to assess patient factors that predict change in management based on TTE. An abnormal exam was defined as having at least one of the following: ejection fraction < 55%, wall motion, pericardial effusion, pericardial effusion, or other significant abnormality including filling defect. The effect on management was derived from clinical course. We hypothesize that these studies are usually normal and rarely lead to changes in clinical management., Results: 912 TTEs were performed in 806 patients. The median age was 68 years (IQR 57, 77) and 63.5% were male. Syncope (21.7%) or hypotension/hypovolemia (20.5%) were the most common indications for a TTE. In total, 39.4% TTEs were abnormal and only 7.6% resulted in a change in management. Predictive factors associated with an abnormal exam included: age >50, serum troponin ≥0.1 ng/ml, abnormal ECG, and clinical suspicion of heart failure or acute myocardial infarction. A troponin cutoff level <0.25 ng/mL was the most reliable factor to predict no change in management after TTE with a negative predictive value of 94.3% (95% CI 93.1, 95.3)., Conclusion: TTE is commonly used for patient assessment in critically ill surgical patients but the majority of exams are normal without change in clinical management. Certain patient factors, such as troponin level, may help distinguish which patients would benefit from this diagnostic test. Given the considerable cost associated with TTE and the minimal effect on management, guidelines on appropriate use would provide improved patient value., Competing Interests: Declaration of Competing Interest None., (Copyright © 2021. Published by Elsevier Ltd.)

Interindividual variation in behavior and brain activity is universal and provides substrates for natural selection [1-9]. Selective pressures shift the expression of behavioral traits at the population level [10, 11], but the accompanying changes of the underlying neural circuitry have rarely been identified [12, 13]. Selection likely acts through the genetic and/or epigenetic underpinnings of neural activity controlling the selected behavior [14]. Endocrine and neuromodulatory systems participate in behavioral diversity and could provide the substrate for evolutionary modifications [15-21]. Here, we examined brain-wide patterns of activity in larval zebrafish selectively bred over two generations for extreme differences in habituation of the acoustic startle response (ASR) [22]. The ASR is an evolutionarily conserved defensive behavior induced by strong acoustic/vibrational stimuli. ASR habituation shows great individual variability that is stable over days and heritable [4, 22]. Selection for high ASR habituation leads to stronger sound-evoked activation of ASR-processing brain areas. In contrast, animals selected for low habituation displayed stronger spontaneous activity in ASR-processing centers. Ablation of dopaminergic tyrosine hydroxylase (TH) neurons decreased ASR sensitivity. Independently selected ASR habituation lineages link the effect of behavioral selection to dopaminergic caudal hypothalamus (HC) neurons [23]. High ASR habituation co-segregated with decreased spontaneous swimming phenotypes, but visual startle responses were unaffected. Furthermore, high- and low-habituation larvae differed in stress responses as adults. Thus, selective pressure over a couple of generations on ASR habituation behavior is able to induce substantial differences in brain activity, carrying along additional behaviors as piggyback traits that might further affect fitness in the wild. VIDEO ABSTRACT., Competing Interests: Declaration of Interests The authors declare no competing interests., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Gold nanoparticles (AuNPs) are increasingly used in biomedical applications, hence understanding the processes that affect their biocompatibility and stability are of significant interest. In this study, we assessed the stability of peptide-capped AuNPs and used the embryonic zebrafish ( Danio rerio ) as a vertebrate system to investigate the impact of synthesis method and purity on their biocompatibility. Using glutathione (GSH) as a stabilizer, Au-GSH nanoparticles with identical core sizes were terminally modified with Tryptophan (Trp), Histidine (His) or Methionine (Met) amino acids and purified by either dialysis or ultracentrifugation. Au-GSH-(Trp) 2 purified by dialysis elicited significant morbidity and mortality at 200 μg/mL, Au-GSH-(His) 2 induced morbidity and mortality after purification by either method at 20 and 200 μg/mL, and Au-GSH-(Met) 2 caused only sublethal responses at 200 μg/mL. Overall, toxicity was significantly reduced and ligand structure was improved by implementing ultracentrifugation purifications at several stages during the multi-step synthesis and surface modification of Au-GSH nanoparticles. When carefully synthesized at high purity, peptide-functionalized AuNPs showed high biocompatibility in biological systems., Competing Interests: The authors declare no conflict of interest.