Molecular characterization of the severe acute respiratory syndrome coronavirus has revealed genetic diversity among isolates. The spike (S) glycoprotein, the major target for vaccine and immune therapy, shows up to 17 substitutions in its 1,255-aa sequence; however, the biologic significance of these changes is unknown. Here, the functional effects of S mutations have been determined by analyzing their affinity for a viral receptor, human angiotensin-converting enzyme 2 (hACE-2), and their sensitivity to Ab neutralization with viral pseudotypes. Although minor differences among eight strains transmitted during human outbreaks in early 2003 were found, substantial functional changes were detected in S derived from a case in late 2003 from Guangdong province [S(GD03T0013)] and from two palm civets, S(SZ3) and S(SZ16). S(GD03T0013) depended less on the hACE-2 receptor and was markedly resistant to Ab inhibition. Unexpectedly, Abs that neutralized most human S glycoproteins enhanced entry mediated by the civet virus S glycoproteins. The mechanism of enhancement involved the interaction of Abs with conformational epitopes in the hACE-2-binding domain. Finally, improved immunogens and mAbs that minimize this complication have been defined. These data show that the entry of severe acute respiratory syndrome coronaviruses can be enhanced by Abs, and they underscore the need to address the evolving diversity of this newly emerged virus for vaccines and immune therapies.angiotensin-converting enzyme 2 ͉ enhancement ͉ immunoglobulin G ͉ pseudovirus

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Objectives: The objective was to compare video-assisted laryngoscopy (VAL) to direct laryngoscopy (DL) on success rate and complication rate of intubations performed in a pediatric emergency department (ED).Methods: This is a retrospective cohort study of attempted intubations of children aged 0-18 years in a pediatric ED between 2004 and 2014 with first attempt by an ED provider. In VAL, the laryngoscopist attempts direct visualization of the glottis with a C-MAC video laryngoscope while the video monitor is used for real-time guidance by a supervisor, back-up visualization for the laryngoscopist should the direct view be inadequate, and confirmation of endotracheal tube passage through the vocal cords. We performed univariate comparisons of intubations using DL to intubations using VAL on rates of firstpass success, complications, and whether the patient was successfully intubated by an ED provider. We then created a logistic regression model to adjust for provider experience level, difficult airway characteristics, and indications for intubation to compare intubations using DL to intubations using VAL for each outcome.Results: We identified 452 endotracheal intubations of 422 unique patients, of which 445 intubations had a first attempt by an ED provider. Six intubations were excluded due to insufficient information available in the record. Of the included intubations, 240 (55%) were attempted with DL and 199 (45%) with VAL. The overall first-pass success rate was 71% in the DL group and 72% in the VAL group. After adjustment for covariates, the first-pass success rate was similar between laryngoscopy approaches (adjusted odds ratio = 1.23, 95% confidence interval = 0.78 to 1.94). Conclusions:We found no difference between DL and VAL with regard to first-pass intubation success rate, complication rate, or rate of successful intubation by ED providers for children undergoing intubation in a pediatric ED.ACADEMIC EMERGENCY MEDICINE 2016;23:870-877