Hydrophobic Chitosan Nanoparticles Loaded with Carvacrol against Pseudomonas aeruginosa Biofilms.

Pseudomonas aeruginosa infections have become more challenging to treat and eradicate due to their ability to form biofilms. This study aimed to produce hydrophobic nanoparticles by grafting 11-carbon and three-carbon alkyl chains to a chitosan polymer as a platform to carry and deliver carvacrol for improving its antibacterial and antibiofilm properties. Carvacrol-chitosan nanoparticles showed ζ potential values of 10.5-14.4 mV, a size of 140.3-166.6 nm, and an encapsulation efficiency of 25.1-68.8%. Hydrophobic nanoparticles reduced 46-53% of the biomass and viable cells (7-25%) within P. aeruginosa biofilms. Diffusion of nanoparticles through the bacterial biofilm showed a higher penetration of nanoparticles created with 11-carbon chain chitosan than those formulated with unmodified chitosan. The interaction of nanoparticles with a 50:50 w/w phospholipid mixture at the air-water interface was studied, and values suggested that viscoelasticity and fluidity properties were modified. The modified nanoparticles significantly reduced viable P. aeruginosa in biofilms (0.078-2.0 log CFU·cm-2) and swarming motility (40-60%). Furthermore, the formulated nanoparticles reduced the quorum sensing in Chromobacterium violaceum. This study revealed that modifying the chitosan polarity to synthesize more hydrophobic nanoparticles could be an effective treatment against P. aeruginosa biofilms to decrease its virulence and pathogenicity, mainly by increasing their ability to interact with the membrane phospholipids and penetrate preformed biofilms.

Full genome sequence of the first SARS-CoV-2 detected in Mexico.

SARS-CoV-2 was first detected in the city of Wuhan, Hubei Province, China. In this report, we describe the complete genome sequence of the first imported SARS-CoV-2, detected in a Mexican patient who had traveled to Bergamo, Italy. Phylogenetic analysis showed that this isolate belongs to subclade A2a (lineage G) and is closely related to isolates from Finland, Germany and Brazil, all of which were from patients with a history of travel to Italy. This is the first report of the complete genome sequence of this virus in Mexico.

Gold Half-Shell-Coated Paclitaxel-Loaded PLGA Nanoparticles for the Targeted Chemo-Photothermal Treatment of Cancer.

Conventional cancer therapies suffer from nonspecificity, drug resistance, and a poor bioavailability, which trigger severe side effects. To overcome these disadvantages, in this study, we designed and evaluated the in vitro potential of paclitaxel-loaded, PLGA-gold, half-shell nanoparticles (PTX-PLGA/Au-HS NPs) conjugated with cyclo(Arg-Gly-Asp-Phe-Lys) (cyRGDfk) as a targeted chemo-photothermal therapy system in HeLa and MDA-MB-231 cancer cells. A TEM analysis confirmed the successful gold half-shell structure formation. High-performance liquid chromatography showed an encapsulation efficiency of the paclitaxel inside nanoparticles of more than 90%. In the release study, an initial burst release of about 20% in the first 24 h was observed, followed by a sustained drug release for a period as long as 10 days, reaching values of about 92% and 49% for NPs with and without near infrared laser irradiation. In in vitro cell internalization studies, targeted nanoparticles showed a higher accumulation than nontargeted nanoparticles, possibly through a specific interaction of the cyRGDfk with their homologous receptors, the ανß3 y ανß5 integrins on the cell surface. Compared with chemotherapy or photothermal treatment alone, the combined treatment demonstrated a synergistic effect, reducing the cell viability to 23% for the HeLa cells and 31% for the MDA-MB-231 cells. Thus, our results indicate that these multifuncional nanoparticles can be considered to be a promising targeted chemo-photothermal therapy system against cancer.

FPGA realization of four chaotic interference cases in a terrestrial trajectory model and application in image transmission.

This article presents a technique to integrate two dynamical models, a four-wing spherical chaotic oscillator and the elliptical path described by the planet Earth during its translation movement around the sun. Four application cases are derived from the system by varying the dynamics of the chaotic oscillator and these can be applied in information encryption to transmit RGB and grayscale images modulated by CSK. Consequently, the three main contributions of this work are (1) the emulation of the trajectories of the planet Earth with chaotic interference, (2) the CSK modulation and image encryption in a master-slave synchronization topology, and (3) the CSK demodulation for decryption without loss of information with respect to the original information. The three contributions are based on VHDL code implementation. The results of the synchronization, encryption and decryption technique were verified by means of time series and the encrypted images showed a correlation less than - 0.000142 and - 0.0003439 for RGB and grayscale format, respectively, while the retrieved image shows a complete correlation with the image original. In this work, the co-simulations were performed between MATLAB/Simulink and Vivado, using the VHDL language on two FPGA boards from different manufacturers, namely, Xilinx Artix-7 AC701 and Intel Cyclone IV.

Human Metapneumovirus: Etiological Agent of Severe Acute Respiratory Infections in Hospitalized and Deceased Patients with a Negative Diagnosis of Influenza.

Human metapneumovirus (HMPV) is one of the four major viral pathogens associated with acute respiratory tract infections (ARI) and creates a substantial burden of disease, particularly in young children (<5 years) and older individuals (≥65 years). The objective of this study was to determine the epidemiological behavior of HMPV in Mexico. This retrospective study was conducted over a nine-year period and used 7283 influenza-negative respiratory samples from hospitalized and deceased patients who presented Severe Acute Respiratory Infection (SARI). The samples were processed with the help of qualitative multiplex RT-PCR for simultaneous detection of 14 respiratory viruses (xTAG® RVP FAST v2). 40.8% of the samples were positive for respiratory viruses, mainly rhinovirus/enterovirus (47.6%), respiratory syncytial virus (15.9%), HMPV (11.1%) and parainfluenza virus (8.9%). Other respiratory viruses and co-infections accounted for 16.5%. HMPV infects all age groups, but the most affected group was infants between 29 days and 9 years of age (65.6%) and adults who are 40 years and older (25.7%). HMPV circulates every year from November to April, and the highest circulation was observed in late winter. The results of this study aim to raise awareness among clinicians about the high epidemiological impact of HMPV in young children and older individuals in order to reduce the economic burden in terms of health care costs.

Variación post absortiva de la concentración serica de vitamina C en adultos de la tercera edad / Post absorptive variation of the serum concentration of vitamin C in elderly people

Con el objetivo de determinar la variación de la concentración sérica de vitamina C en personas de la tercera edad, hicimos un estudio comparativo con adultos jóvenes de ambos sexos distribuidos en dos grupos de 14 sujetos cada uno a los que previo dosaje basal en ayuno se les administró un gramo de vitamina C y se midió a los 30, 90, 180 y 300 minutos la concentración sérica de dicha vitamina según el método de Roe y Kuther; luego se aplicó la T de Student y ANOVA, obteniendo los siguientes resultados: 1.- La concentración sérica basal de vitamina C en adultos jóvenes es de 1.16mg/dt. 2.- La concentración sérica basal de vitamina C en adultos de la tercera edad es de 0,82mg/dt. 3.- La concentración sérica postabsortiva de vitamina C en adultos jóvenes aumentó significativamente a los 90 minutos. 4.- La concentración sérica postabsortiva de vitamina C en adultos de la tercera edad aumenta significativamente en todos los tiempos en relacion al basal, alcanzando el máximo a los 300 minutos. 5.- La concentración sérica poostabsortiva de vitamina C es más lenta y sostenida en adultos de la tercera edad que en adultos jóvenes.

With the objective to determine the post absortive variation of the serum concentration séric of vitamin C in elderly people, we did a comparative study with young people of both sexes distributed in two groups of 14 people in each to them to whom previous basal dosage in fast were given a gram of vitamin C and it was measured at 30, 90, 180, and 300 minutes the serum concentration of this vitamin according to the Roe and Kutcher method; after that the student t and the Anova was applied getting the ollowing results: 1.- The serum basal concentration of vitamin C in young people is of e1.16mg/dt. 2.- The serum basal concentration in ederly peple is of 0,82mg/dt. 3.- The serum post-absortiva concentration of vitamin C in young people has greatly been increased at 90 minutes. 4.- The serum post-absortiva concentrationof vitamin C in elderly people gratly increase any time in connection with basal, getting the maximum at 300 minutes. 5.- The serum post-absortiva concentration of vitamin C is slower and shrp in elderly people than in young people.