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Carlos Enrique Escárcega-González,1,2 JA Garza-Cervantes,1,2 A Vázquez-Rodríguez,1,2 Liliana Zulem Montelongo-Peralta,1,2 MT Treviño-González,3 E Díaz Barriga Castro,4 EM Saucedo-Salazar,4 RM Chávez Morales,5 DI Regalado Soto,5 FM Treviño González,5 JL Carrazco Rosales,6 Rocío Villalobos Cruz,6 José Rubén Morones-Ramírez1,2 1Universidad Autónoma de Nuevo León, Facultad de Ciencias Químicas, Pedro de Alba, S/N, San Nicolás de los Garza, Nuevo León, México; 2Centro de Investigación en Biotecnología y Nanotecnología, Facultad de Ciencias Químicas, Universidad Autónoma de Nuevo León, Parque de Investigación e Innovación Tecnológica, Apodaca, Nuevo León, México; 3Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, Pedro de Alba, S/N, San Nicolás de los Garza, Nuevo León, México; 4Centro de Investigación en Química Aplicada, Saltillo, Coah, México; 5Departamento de Fisiología y Farmacología, Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Colonia Ciudad Universitaria, Aguascalientes, México; 6Departamento de Microbiología, Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Colonia Ciudad Universitaria, Aguascalientes, Mexico Introduction: One of the main issues in the medical field and clinical practice is the development of novel and effective treatments against infections caused by antibiotic-resistant bacteria. One avenue that has been approached to develop effective antimicrobials is the use of silver nanoparticles (Ag-NPs), since they have been found to exhibit an efficient and wide spectrum of antimicrobial properties. Among the main drawbacks of using Ag-NPs are their potential cytotoxicity against eukaryotic cells and the latent environmental toxicity of their synthesis methods. Therefore, diverse green synthesis methods, which involve the use of environmentally friendly plant extracts as reductive and capping agents, have become attractive to synthesize Ag-NPs that exhibit antimicrobial effects against resistant bacteria at concentrations below toxicity thresholds for eukaryotic cells. Purpose: In this study, we report a green one-pot synthesis method that uses Acacia rigidula extract as a reducing and capping agent, to produce Ag-NPs with applications as therapeutic agents to treat infections in vivo. Materials and methods: The Ag-NPs were characterized using transmission electron microscopy (TEM), high-resolution TEM, selected area electron diffraction, energy-dispersive spectroscopy, ultraviolet–visible, and Fourier transform infrared. Results: We show that Ag-NPs are spherical with a narrow size distribution. The Ag-NPs show antimicrobial activities in vitro against Gram-negative (Escherichia coli, Pseudomonas aeruginosa, and a clinical multidrug-resistant strain of P. aeruginosa) and Gram-positive (Bacillus subtilis) bacteria. Moreover, antimicrobial effects of the Ag-NPs, against a resistant P. aeruginosa clinical strain, were tested in a murine skin infection model. The results demonstrate that the Ag-NPs reported in this work are capable of eradicating pathogenic resistant bacteria in an infection in vivo. In addition, skin, liver, and kidney damage profiles were monitored in the murine infection model, and the results demonstrate that Ag-NPs can be used safely as therapeutic agents in animal models. Conclusion: Together, these results suggest the potential use of Ag-NPs, synthesized by green chemistry methods, as therapeutic agents against infections caused by resistant and nonresistant strains. Keywords: silver nanoparticles, green synthesis, in vitro antibacterial activity, in vivo antibacterial activity, skin infection, toxicological study

Introduction: Warfighters are exposed to life-threatening injuries daily and according to the Joint Trauma System Military Clinical Practice Guideline-Global Snake Envenomation Management snakebites are a concerning threat in all theaters of operation. Snake venom is a complex mixture of toxins including phospholipases A2 (PLA2) and snake venom metalloproteinases (SVMP) that produce myotoxic, hemotoxic, and cytotoxic injuries. Antibody-based antivenom is the standard of care but new approaches including small-molecule inhibitors have gained attention in recent years. Doxycycline is an effective inhibitor of human metalloproteinases and PLA2. The enzymatic activities of 3 phylogenetically distinct snakes: Agkistrodon piscivorus, Naja kaouthia, and Daboia russelii were tested under inhibitory conditions using doxycycline., Materials and Methods: Enzymatic activity of PLA2 and SVMP was measured in N. kaouthia, D. russelii, and A. piscivorus venom alone and with doxycycline using EnzChek Phospholipase A2 and Gelatinase Assay Kits. A 1-way ANOVA with Tukey's post-hoc test was used to conduct comparative analysis. The median lethal dose of the venoms, the effective dose of doxycycline, and creatine kinase (CK) inhibition levels were measured in a murine model with adult Bagg Albino (BALB/c) mice using intramuscular injections. Median lethal and effective doses were determined using Spearman-Karber's method and a 1-way ANOVA with Tukey's post-hoc test was used to compare CK inhibition levels., Results: Phospholipases A2 activity was reduced to 1.5% to 44.0% in all 3 venoms in a dose-dependent manner using 0.32, 0.16, and 0.08 mg/mL doxycycline when compared to venom-only controls (P < .0001) (Fig. 1A). Snake venom metalloproteinases activity was reduced to 4% to 62% in all 3 venoms in a dose-dependent manner using 0.32, 0.16, and 0.08 mg/mL doxycycline (P < .0001) (Fig. 1B). The lethal dose (LD50) values of the venoms in the murine model were calculated as follows: A. piscivorus = 20.29 mg/kg (Fig. 2A), N. kaouthia = 0.38 mg/kg (Fig. 2B), and D. russelii = 7.92 mg/kg (Fig. 2C). The effective dose (ED50) of doxycycline in A. piscivorus was calculated to be 20.82 mg/kg and 72.07 mg/kg when treating D. russelii venom. No ED50 could be calculated when treating N. kaouthia venom (Fig. 3). Creatine kinase activity was significantly decreased in all 3 venoms treated with doxycycline (P < .0001) (Fig. 4)., Conclusion: Doxycycline reduced PLA2- and SVMP-related lethality, particularly in A. piscivorus envenomings and in a limited capacity with D. russelii revealing its promise as a treatment for snakebites. In addition, CK activity, a common indicator of muscle damage was inhibited in mice that received doxycycline-treated venom. The doxycycline concentrations identified in the ED50 studies correspond to 1,456 to 5,061 mg dosages for a 70 kg human. Factors including venom yield and snake species would affect the actual dosage needed. Studies into high-dose doxycycline safety and its effectiveness against several snake species is needed to fully translate its use into humans. Based on this work, doxycycline could be used as a treatment en route to higher echelons of care, providing protection from muscle damage and reducing lethality in different snake species., (Published by Oxford University Press on behalf of the Association of Military Surgeons of the United States 2024. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

Introduction: Restrictive e-cigarette policies have not allowed for the characterization of the sale of these tobacco products in the countries where they are implemented. This is because it is believed that there are no stores. However, the use of e-cigarettes persists in these countries., Methods: A content analysis of electronic cigarette points of sale through the internet in Mexico was conducted. Cross-sectional study. Structured searches were performed in the Google Maps search engine with the terms "electronic cigarette store" and "vape store" in combination with the name of each state of Mexico, in the period from October 2021 to February 2022., Results: A total of 695 e-cigarette stores were located, of which 481 (69.2%) were physical stores, 207 hybrid stores (29.8%), 4 online stores (0.6%) and 3 (0.4%) vending machines. A total of 316 e-cigarette brands and 578 vape liquid brands were identified. The sales attraction strategy they used the most was free shipping of products (85.8%). Stores used WhatsApp (92.5%), Facebook (86.3%) and Instagram (74.4%) to promote their products. Only 35.1% of stores checked the age of their customers, of which, 95.9% asked if the customer was of legal age and 4.1% asked for the date of birth. In addition, 25.6% of the stores warned about nicotine addiction and 24.2% specifically about the ingredients of the liquids., Conclusions: E-cigarettes are widely available and marketed in a variety of retail outlets in Mexico. The high number of stores, brands of liquids, and e-cigarettes indicates non-compliance with existing regulations., Implications: E-cigarette consumption has increased globally, even in countries with restrictive regulations. However, there is limited data on the density and characteristics of vape stores in low- and middle-income countries with restrictive regulations. This study found no significant differences in e-cigarette sales between countries with permissive and restrictive regulations. Therefore, it is suggested that, in addition to establishing restrictive policies on the sale of e-cigarettes, their enforcement should also be monitored. Countries with restrictive measures should regulate Internet sales and promotion of e-cigarettes with greater emphasis., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Context: Studies indicate a decrease in spatial memory across species as they age. Moreover, consistent administration of Gonadotropin-releasing hormone (GnRH) improves learning abilities in older rats that have undergone gonadectomy., Objective: The aim of this study was to investigate the effects of the GnRH agonist, leuprolide acetate (LA) on spatial memory in aged intact male rats and the expression of proteins associated with hippocampal plasticity., Subjects and Methods: Aged male rats were injected with LA or saline every three days for nine weeks to assess the effects of LA on spatial memory. The aged rats were trained in the Morris Water Maze for four days, and the evaluation took place on the fifth day. Additionally, the Y-maze test was used to investigate short-term spatial memory. The expression of spinophilin and microtubule-associated protein 2 (MAP2) in the hippocampus was measured., Results: Behavioral tests revealed that LA improves spatial memory in aged rats. Additionally, we observed increased expression of spinophilin and MAP2 in the hippocampus of aged male rats following LA treatment. Based on these results, the administration of LA holds is a potential treatment for restoring cognitive function in aged individuals., Competing Interests: The authors declare that they have no conflict of interest., (©2024 Acta Endocrinologica (Buc).)

The accumulation of microorganisms, plants, algae, or small animals on wet surfaces that have a mechanical function causes biofouling, which can result in structural or other functional deficiencies. The maritime shipping industry must constantly manage biofouling to optimize operational performance, which is a common and long-lasting problem. It can occur on any metal structure in contact with or submerged in ocean water, which represents additional costs in terms of repairs and maintenance. This study is focused on the production of antifouling coatings, made with nanoparticles of copper selenide (CuSe NPs) modified with gum arabic, within a water-base acrylic polymeric matrix. During the curing of the acrylic resin, the CuSe NPs remain embedded in the resin, but this does not prevent the release of ions. The coatings released copper and selenium ions for up to 80 days, and selenium was the element that was released the most. The adhesion of film coatings to metallic substrates showed good adhesion, scale 5B (ASTM D3359 standard). Antimicrobial activity tests show that the coatings have an inhibitory effect on Escherichia coli and Candida albicans . The effect is more noticeable when the coating is detached from the substrate and placed on a growing medium, compared to the coating on a substrate. Scanning electron microscopy (SEM) observations show that nanostructured CuSe coatings are made up of rod-shaped and spherical particles with an average particle size of 101.6 nm and 50 nm, respectively. The energy dispersive X-ray spectroscopy (EDS) studies showed that the ratio of selenium nanoparticles is greater than that of copper and that their distribution is homogeneous.

The environmental degradation of the films used in packaging is a key factor in their commercial use. Industrial and academic research is aimed at obtaining materials that have degradation features that ensure their eco-sustainability but, at the same time, preserve their use properties during storage and distribution periods. This study analyzes the degradability behavior over time of commercial packaging that meets the requirements of the UNE 13432 standard and the prEN 17427 (2020) home composting certification requirements under standard storage conditions. The study attempts to provide insight into the durability of the films under standard storage conditions, verifying that this type of packaging has a useful life of more than 12 months and that after this storage period it still retains the usability properties for which it was conceived. The analyzed sample has been manufactured using a three-layer technology under some commercial formulations based on PBAT + STARCH + PLA and has been analyzed monthly for 12 consecutive months. The macroscopic monitoring of the degradation of the sample has been carried out through the evolution of the mechanical properties and the quantification of the color changes (very important in films) via colorimetry. The nature of the observed variations has been justified at the microstructural level from the data obtained in calorimetric analysis (DSC) and from the characterization using FTIR. The results indicate a loss of properties in the tensile, elongation and impact tests and a behavior of stability or improvement in the tear properties of the film. Analyzing the microstructural changes, it is observed that the degradation of a hydrolytic and thermo-oxidative type occurs in the amorphous part of the film. The conclusion of this study is that the proposed packaging, focused on domestic composting and stored under standard conditions, has a useful life of more than 12 months. This period should be sufficient to cover the stages of production, storage and final use.

Señor editor: La emigración de enfermeros mexicanos hacia el extranjero es un tema que cobra relevancia durante la pandemia por Covid-19, principalmente por la necesidad de contar con profesionales calificados que hagan frente a esta situación de emergencia sanitaria. Pero ¿por qué los enfermeros están emigrando cuando México también tiene escasez de estos profesionales?..