Preparation and Characterization of Lignin Nanoparticles from Different Plant Sources.

This article presents new research on producing lignin nanoparticles (LNPs) using the antisolvent nanoprecipitation method. Acetone (90%) served as the lignin solvent and water (100%) as the antisolvent, using five types of lignins from various sources. Comprehensive characterization techniques, including NMR, GPC, FTIR, TEM, and DLS, were employed to assess both lignin and LNP properties. The antioxidant activity of the LNPs was evaluated as well. The results demonstrated the successful formation of spherical nanoparticles below 100 nm with initial lignin concentrations of 1 and 2%w/v. The study highlighted the crucial role of lignin purity in LNP formation and colloidal stability, noting that residual carbohydrates adversely affect efficiency. This method offers a straightforward, environmentally friendly approach using cost-effective solvents, applicable to diverse lignin sources. The innovation of this study lies in its demonstration of a cost-effective and eco-friendly method to produce stable, nanometric-sized spherical LNPs. These LNPs have significant potential as reinforcement materials due to their reinforcing capability, hydrophilicity, and UV absorption. This work underscores the importance of starting material purity for optimizing the process and achieving the desired nanometric dimensions, marking a pioneering advancement in lignin-based nanomaterials.

The challenges of mental health in Chilean university students.

Mental health is a crucial issue in Chile and worldwide, gaining even more relevance following social events in Chile in 2019, including the sociopolitical crisis and the COVID-19 pandemic. In Chile, over 20% of adolescents experience mental health problems such as anxiety, depression, and stress, with many going untreated due to limited access or the stigma associated with these issues. The COVID-19 pandemic has exacerbated this situation, with a 25% increase in the prevalence of anxiety and depression. The university population is particularly vulnerable to mental health challenges due to the unique pressures of the academic environment, including increased academic demands and the acquisition of university-related behaviors that can negatively impact physical and mental health, with notable gender differences. Effectively addressing these issues is essential for ensuring the emotional and psychological well-being of university students. Specific policies and programs are needed to address the mental health needs of university adolescents and ensure that they have access to mental health services required to navigate the challenges of daily life. A methodology reflective of the essayistic approach guides this exploration, which is characterized by critical reflection and structured argumentation.

Perfil etiológico de las meningitis adquiridas en la comunidad en pacientes adultos en el Complejo Asistencial Sótero del Río, Santiago 2011-2017 / Community acquired meningitis in Santiago, Chile, 2011-2017

INTRODUCCIÓN: En Chile existe poca información sobre los microorganismos causantes de meningitis adquirida en la comunidad (MAC), la que es relevante a la hora de escoger el esquema antimicrobiano empírico. OBJETIVO: Describir la microbiología de MAC en pacientes mayores de 15 años atendidos en un hospital público de Santiago (Chile). METODOLOGÍA: Revisión de cultivos de líquido cefalorraquídeo positivos durante 2011-2017. Se recolectó la información clínica de los pacientes incluidos. Se excluyeron cultivos considerados como contaminación y las meningitis post-quirúrgicas. RESULTADOS: Se identificaron 20 episodios de meningitis bacteriana aguda (MBA) y seis episodios de meningitis criptocócica (MC) entre 2.720 cultivos. Los microorganismos causantes de MBA fueron: Streptococcus pneumoniae (50%), Listeria monocytogenes (25%) y otros cinco agentes (25%). Todos los pacientes con infección por L. monocytogenes presentaban alguna comorbilidad significativa. Cuatro de cinco casos de MC presentaban infección por VIH. CONCLUSIÓN: Streptococcus pneumoniae fue el microorganismo más frecuente de las MAC en esta serie, seguido por L. monocytogenes. Las recomendaciones actuales de esquemas empíricos de MAC consideran adecuadamente la cobertura de S. pneumoniae en todos los pacientes y de L. monocytogenes solo ante factores de riesgo. Además, es relevante considerar MC en casos en pacientes inmunocomprometidos.

BACKGROUND: In Chile, there is scarce information on the frequency of the causative microorganisms of community-acquired meningitis (CAM), which is relevant for the choice of empiric treatment. AIM: To describe the microbiology of CAM in patients over 15 years treated at a public hospital in Santiago (Chile). METHODS: Retrospective review of positive cerebrospinal fluid cultures during 2011-2017. Clinical information of the included patients was collected. Cultures considered as contamination and cases of post-surgical meningitis were excluded. RESULTS: We identified 20 episodes of bacterial meningitis (BM) and six episodes of cryptococcal meningitis (CM) in 2720 cultures. The microorganisms identified in BM cases were Streptococcus pneumoniae (50%), Listeria monocytogenes (25%) and five other agents (25%). All patients with L. monocytogenes infection had at least one well-known risk factor for this infection. Four of the five cases of CM had HIV infection. CONCLUSION: Streptococcus pneumoniae was the most frequent causative microorganism of CAM in this series, followed by L. monocytogenes. Current recommendations for empiric CAM regimens adequately consider coverage for S. pneumoniae in all patients and for L. monocytogenes only in those with risk factors. Furthermore, it is relevant to consider CM in cases involving immunocompromised patients.

Validation of Reference Genes in a Population of Blueberry (Vaccinium corymbosum) Plants Regenerated in Colchicine.

For the first time we report the validation of reference genes in plants from a population of blueberry (Vaccinium corymbosum) clones cultured in vitro on a colchicine-supplemented medium. Nodal segment explants of the cultivar Duke were regenerated by organogenesis under different periods of colchicine 1 mg/L exposure (1, 2, 3, 5, 30 days). The clones selected for the study showed variability for phenotypic traits after 2 years of adaptation to field conditions, compared to plants of the donor genotype that were regenerated on a medium without colchicine. Vaccinium myrtillus (GAPDH) and Vaccinium macrocarpon (ATP1, NADH, RPOB and COX2) were used as reference genomes for primer design. The results show that colchicine treatments can cause genomic changes in blueberry plants. At the molecular level, exposure of plants to colchicine in early periods could promote an increase in gene expression of specific genes such as ATP1, COX2, GAPDH, MATK, NADH and RPOB. However, prolonged exposure (30 days) could decrease gene expression of the genes studied. For qPCR assays, the primers designed for ATP1, COX2, GAPDH and MATK genes showed high efficiency. In addition, the GAPDH, ATP1, NADH and COX2 genes showed high stability and could be recommended as potential reference genes for gene expression assays in Vaccinium.

Plant-growth-promoting bacteria from rhizosphere of Chilean common bean ecotype (Phaseolus vulgaris L.) supporting seed germination and growth against salinity stress.

Salinity abiotic stress is increasing day by day due to continuous global warming and climate change. This is also becoming one of the major causes behind the reduction in crop production. Plant-bacteria interaction plays an essential role in improving crop yield without using any chemical fertilizers. The present study aims to characterize the interaction between plant-growth-promoting bacteria (PGPB) and their role in mitigating salinity stress for local variety crops. Therefore, in this work, two PGPB, namely, Bacillus proteolyticus Cyn1 and Bacillus safensis Cyn2, were isolated from rhizospheric soil of the Chilean common bean ecotype "Sapito" (Phaseolus vulgaris L.), and their PGPB traits were analyzed. Cyn1 can produce NH3 and HCN and also secrete siderophores, whereas Cyn2 produced NH3 and siderophores but responded negatively to HCN production. Both the isolated bacteria have shown a positive result for ACC deaminase production, phosphate solubilization, and catalase enzyme secretion. Under all three tested abiotic stresses, i.e., temperature, water, and salinity, both the bacteria and their consortium have demonstrated positive responses. Cyn1 under temperature stress and water stress can produce a biofilm network to combat the stress. While under salinity stress, both the PGPB isolates indicated the production of stress components and cytoplasmic inclusion bodies. Based on the response, among all other abiotic stresses, salinity stress was chosen for further plant-bacteria interaction study and growth. Visible root colonization of the bacteria has been observed in comparison to the control. The germination index was 100% for all experimental setups of seed bacterization, both under control conditions and salinity stress. Both bacteria responded with good PGP traits that helped in the growth of healthy plants after the bacterial treatment in final pot experiments. Additionally, the consortium and the plants treated with Cyn1 have demonstrated high production of photosynthetic pigments in both experimental setups. Both B. proteolyticus Cyn1 and B. safensis Cyn2 have shown promising PGP characters and efficient response against toxicity related to salinity. Hence, both of these bacteria and consortium can be used for improved agricultural production of Chilean native common beans in the near future.

Bovine Fetal Mesenchymal Stem Cells Obtained From Omental Adipose Tissue and Placenta Are More Resistant to Cryoprotectant Exposure Than Those From Bone Marrow.

Recent studies have shown promise for the development of cellular therapies with mesenchymal stem cells (MSCs) in livestock species, specifically bovines, and cryopreservation is highly relevant for the advancement of these applications. The use of permeable and/or non-permeable cryoprotectant solutions is necessary to reduce cell damage during freezing and thawing, but these same compounds can also cause negative effects on MSCs and their therapeutic properties. Another important factor to consider is the tissue source of MSCs, since it is now known that MSCs from different tissues of the same individual do not behave the same way, so optimizing the type and concentration of cryoprotectants for each cell type is essential to achieve a large and healthy population of MSCs after cryopreservation. Furthermore, sources of MSCs that could provide great quantities, non-invasively and without ethical concerns, such as placental tissue, have great potential for the development of regenerative medicine in livestock species, and have not been thoroughly evaluated. The objective of this study was to compare the viability of bovine fetal MSCs extracted from bone marrow (BM), adipose tissue (AT), and placenta (PT), following their exposure (15 and 30 min) to several solutions of permeable (dimethyl sulfoxide and ethylene glycol) and non-permeable (trehalose) cryoprotectants. Viability assays were performed with Trypan Blue to assess post-exposure plasma membrane integrity. The apoptotic potential was estimated analyzing the mRNA abundance of BAX and BCL-2 genes using quantitative rt-PCR. Based on the results of the study, BM-MSC exhibited significantly lower viability compared to AT-MSC and PT-MSC, at both 15 and 30 min of exposure to cryoprotectant solutions. Nevertheless, viability did not differ among treatments for any of the cell types or timepoints studied. BCL-2 expression was higher in BM-MSC compared to AT-MSC, however, BAX/BCL-2 ratio did not differ. In conclusion, AT-MSC and PT-MSC were more resistant that BM-MSC, which showed higher sensitivity to experimental conditions, regardless of the exposure times, and cryoprotectant solutions used in the study.

Infecciones por Elizabethkingia spp. en un hospital universitario: coinfección con SARS-CoV-2 y primer reporte de Elizabethkingia anophelis en Chile / Elizabethkingia spp. infections in a university hospital: coinfection with SARS-CoV-2 and first report of Elizabethkingia anophelis in Chile

INTRODUCCIÓN: Elizabethkingia es un género de bacterias gramnegativas cuya relevancia como patógeno oportunista en hospederos inmunocomprometidos y pacientes críticos ha sido reconocida progresivamente en los últimos años. Este género está compuesto principalmente por E. meningoseptica, E. anophelis y E. miricola. Si bien inicialmente E. meningoseptica fue considerada la especie patógena más relevante, gracias a los avances en las técnicas de identificación microbiológica se ha reconocido a E. anophelis como el principal patógeno de este grupo. OBJETIVO: Caracterizar los casos de infecciones por Elizabethkingia spp. en una red de salud y realizar una breve revisión de esta infección. MATERIAL Y MÉTODOS: Se realizó una revisión de los cultivos positivos para Elizabethkingia spp. en el Laboratorio de Microbiología de la Red de Salud UC-CHRISTUS (Chile) entre los años 2017 y 2021. RESULTADOS: Se obtuvo 17 cultivos positivos correspondientes a siete casos clínicos, todos procedentes de un hospital universitario. Todos los casos poseían factores de riesgo conocidos de infección por Elizabethkingia spp. incluyendo uso de antimicrobianos recientes, por ejemplo, el uso previo de carbapenémicos en 85,7% de los pacientes. Cuatro casos se presentaron en pacientes con neumonía por SARS-CoV-2, una coinfección no previamente reportada en la literatura. Elizabethkingia anophelis fue identificada mediante secuenciación de ARN ribosomal en 80% de las cepas recuperadas, lo que corresponde al primer reporte de esta especie en Chile CONCLUSIÓN: Comunicamos la experiencia clínica de infecciones por este género en un hospital universitario de Chile, incluyendo los primeros casos de coinfección en pacientes cursando neumonía por SARS-CoV-2 y la primera identificación de Elizabethkingia anophelis en Chile.

BACKGROUND: Elizabethkingia is a genus of gramnegative bacteria whose relevance as an opportunistic pathogen in immunosuppressed hosts and critically ill patients has been progressively recognized in recent years. This genus is mainly composed of E. meningoseptica, E. anophelis, and E. miricola. Although E. meningoseptica was initially reported as the most relevant pathogenic species, thanks to advances in microbiological identificaron techniques E. anophelis has been recognized as the main pathogen of this group. AIM: To characterize Elizabethkingia spp.'s infections in a health network and make a brief review of this infection. METHOD: We conducted a review of clinical cultures that were positive for Elizabethkingia sp. in the Microbiology Laboratory of the UC-CHRISTUS Health Network (Chile), between 2017 and 2021. RESULTS: Seventeen positive cultures were obtained corresponding to seven clinical cases, all originating from a university hospital. All cases had known risk factors for Elizabethkingia sp. infection, including recent use of antibiotics. Notably, previous use of carbapenems was present in 85.7% of the patients. Four cases occurred in patients with SARS-CoV-2 pneumonia, a coinfection not previously reported in the literature. Elizabethkingia anophelis was identified by ribosomal RNA sequencing in 80% of the recovered strains, which corresponds to the first report of this species in Chile. CONCLUSION: We report the clinical experience of a university hospital with infections by Elizabethkingia spp., including the first cases of coinfection in patients with SARS-CoV-2 pneumonía and the first identification of Elizabethkingia anophelis in Chile.

[Elizabethkingia spp. infections in a university hospital: coinfection with SARS-CoV-2 and first report of Elizabethkingia anophelis in Chile]. / Infecciones por Elizabethkingia spp. en un hospital universitario: coinfección con SARS-CoV-2 y primer reporte de Elizabethkingia anophelis en Chile.

BACKGROUND: Elizabethkingia is a genus of gramnegative bacteria whose relevance as an opportunistic pathogen in immunosuppressed hosts and critically ill patients has been progressively recognized in recent years. This genus is mainly composed of E. meningoseptica, E. anophelis, and E. miricola. Although E. meningoseptica was initially reported as the most relevant pathogenic species, thanks to advances in microbiological identificaron techniques E. anophelis has been recognized as the main pathogen of this group. AIM: To characterize Elizabethkingia spp.'s infections in a health network and make a brief review of this infection. METHOD: We conducted a review of clinical cultures that were positive for Elizabethkingia sp. in the Microbiology Laboratory of the UC-CHRISTUS Health Network (Chile), between 2017 and 2021. RESULTS: Seventeen positive cultures were obtained corresponding to seven clinical cases, all originating from a university hospital. All cases had known risk factors for Elizabethkingia sp. infection, including recent use of antibiotics. Notably, previous use of carbapenems was present in 85.7% of the patients. Four cases occurred in patients with SARS-CoV-2 pneumonia, a coinfection not previously reported in the literature. Elizabethkingia anophelis was identified by ribosomal RNA sequencing in 80% of the recovered strains, which corresponds to the first report of this species in Chile. CONCLUSION: We report the clinical experience of a university hospital with infections by Elizabethkingia spp., including the first cases of coinfection in patients with SARS-CoV-2 pneumonía and the first identification of Elizabethkingia anophelis in Chile.

Hydroxychloroquine and chloroquine in COVID-19: should they be used as standard therapy?

The pandemic of the new coronavirus, known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has urged the nations to an unprecedented world-wide reaction, including an accelerated exploration of therapeutic options. In the absence of a vaccine and specifically designed antivirals, the medical community has proposed the use of various previously available medications in order to reduce the number of patients requiring prolonged hospitalizations, oxygen therapy, and mechanical ventilation and to decrease mortality from coronavirus disease 2019 (COVID-19). Hydroxychloroquine and chloroquine are among the proposed drugs and are the most widely used so far, despite the lack of robust evidence on their usefulness. The objective of this article is to review and discuss the possible role of these drugs in the therapy of COVID-19.

Artritis psoriásica: La elección del fármaco antirreumático biológico en la Ley Ricarte Soto / Choosing biological agents for the treatment of psoriatic arthritis

The financial coverage granted by law in Chile for patients with psoriatic arthritis who require biological treatment is of paramount importance and a great advance. However physicians must be knowledgeable about the advantages and limitations of this therapy. The challenge of clinicians is to choose the drug with the greater odds of achieving therapeutic success, with less adverse events and lower costs for our health system. This article aims to help doctors to select the best biological treatment for a specific patient, trying to optimize its effectiveness, minimizing adverse effects, always looking for an efficient use of resources.

[Choosing biological agents for the treatment of psoriatic arthritis]. / Artritis psoriásica: La elección del fármaco antirreumático biológico en la Ley Ricarte Soto.

The financial coverage granted by law in Chile for patients with psoriatic arthritis who require biological treatment is of paramount importance and a great advance. However physicians must be knowledgeable about the advantages and limitations of this therapy. The challenge of clinicians is to choose the drug with the greater odds of achieving therapeutic success, with less adverse events and lower costs for our health system. This article aims to help doctors to select the best biological treatment for a specific patient, trying to optimize its effectiveness, minimizing adverse effects, always looking for an efficient use of resources.