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Diazabicyclooctanone inhibitors such as ETX2514 and avibactam have shown enhanced inhibitory performance to fight the antibiotic resistance developed by pathogens. However, avibactam is ineffective against Acinetobacter baumannii infections, unlike ETX2514. The molecular basis for this difference has not been tackled from a molecular approach, precluding the knowledge of relevant information. In this article, the mechanisms involved in the inhibition of OXA-24 by ETX2514 and avibactam are studied theoretically by hybrid QM/MM calculations. The results show that both inhibitors share the same inhibition mechanisms, comprising acylation a deacylation stages. The involved mechanisms include the same number of steps, transition states and intermediates; although they differ in the involved activation barriers. This difference accounts for the dissimilar inhibitory ability of both inhibitors. The molecular reason for this is the endocyclic double bond in the piperidine ring of ETX2514 increasing the ring strain and chemical reactivity on the N6 and C7 atoms, besides the methyl substituent, which enhance the hydrophobic character of the ring. Furthermore, Lys218 and the carboxylated Lys84 of ETX2514, play a crucial role in the mechanism by coordinating their protonation states in an on/off (protonated/deprotonated) manner, favoring the proton transference between the residues and the inhibitor., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Klebsiella pneumoniae carbapenemase (KPC-2) is the most commonly encountered class A β-lactamase variant worldwide, which confer high-level resistance to most available antibiotics. In this article we address the issue by a combined approach involving molecular dynamics simulations and hybrid quantum mechanics/molecular mechanics calculations. The study contributes to improve the understanding, at molecular level, of the acylation and deacylation stages of avibactam involved in the inhibition of KPC-2. The results show that both mechanisms, acylation and deacylation, the reaction occur via the formation of a tetrahedral intermediate. The formation of this intermediate corresponds to the rate limiting stage. The activation barriers are 19.5 kcal/mol and 23.0 kcal/mol for the acylation and deacylation stages, respectively. The associated rate constants calculated, using the Eyring equation, are 1.2 × 10 -1 and 3.9 × 10 -4 (s -1 ). These values allow estimating a value of 3.3 × 10 -3 for the inhibition constant, in good agreement with the experimental value., (© 2021. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Stereotactic surgery is a widely used procedure in neuroscience research to study the brain's regulation of feeding behavior. In line with this notion, this study aims to assess how food consumption and feeding patterns are affected in response to the use of auditory bars that preserve or damage the tympanic membrane during stereotactic surgery. Our previous observations led us to hypothesize that the traumatic tympanic membrane rupture affects food intake and feeding patterns in rats undergoing stereotactic procedures. Thereby, female and male rats were cannulated in the third ventricle (3V) using both types of auditory bars. Post-surgical pain was assessed using the grimace scale. Food intake, meal patterns and weight gain or loss were analyzed for 5-7 consecutive days after surgery. Normal food intake, increased body weight and regular meal patterns were observed from postoperative day 2 when the stereotactic procedure was performed using auditory bars that maintain the integrity of the tympanic membrane. However, tympanic membrane rupture prevented the expected recovery of food intake and body weight. This effect was accompanied by an alteration in eating patterns, which was persistent over 7 days of recovery. Thus, tympanic membrane preservation during surgery is necessary to evaluate short-term feeding patterns. This study demonstrates auditory bars that do not damage the tympanic membrane should be used when performing stereotactic surgery for subsequent analysis of rat behavior., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2020 Barahona, Rojas, Uribe and García-Robles.)

Objective: To evaluate the impact of the implementation of the Infarction Code strategy in patients with acute myocardial infarction diagnosis., Methods: Consecutive patients with ST-elevation acute myocardial infarction ≤12 hours of evolution, were included in the infarction code strategy, before (Group I) and after (Group II). Times of medical attention and major cardiovascular events during hospitalization were analyzed., Results: 1227 patients were included, 919 men (75%) and 308 women (25%) with an average age of 62 ± 11 years. Among Group I and Group II, percutaneous coronary intervention reperfusion therapy changed (16.6% to 42.6%), fibrinolytic therapy (39.3% to 25%), and patients who did not receive any form of reperfusion therapy (44% to 32.6%; p < 0.0001). Times of medical attention decreased significantly (door-to-needle time decreased from 92 to 72 minutes, p = 0.004; door-to-balloon time decreased from 140 to 92 minutes, p < 0.0001). Kidney failure (24.6% vs. 17.9%; p = 0.006), major complications (35.3% to 29.3%), and death (21% vs. 12%; odds ratio: 0.52; 95% confidence interval: 0.38-0.71; p = 0.004). also decreased., Conclusion: The Infarction Code strategy improved treatment, times of medical attention and decreased complications and death in these patients.