Universidad de Magallanes
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Estimating the prevalence of persistent symptoms after SARS-CoV-2 infection (post-COVID-19 syndrome): a regional cross-sectional study protocol
No full textIntroduction The COVID-19 pandemic, driven by the SARS-CoV-2 virus, has had a significant global impact, with over 775 million cases reported and more than 7 million deaths as of July 2024. In Chile, approximately 5.4 million people have been infected, with a substantial proportion experiencing persistent symptoms known as post-COVID-19 syndrome. This study aims to estimate the prevalence of post-COVID-19 syndrome in Punta Arenas, Chile, and to explore the associated symptoms, mainly focusing on psychological, physical and molecular impacts on the affected population.Methods and analysis This cross-sectional study will use stratified random sampling to select a representative sample of 282 adults from Punta Arenas. Participants eligible for the study are those who had tested positive for SARS-CoV-2 by reverse transcription-quantitative PCR between July 2022 and July 2023. Data collection will include comprehensive clinical assessments, psychological evaluations and laboratory analyses of inflammatory biomarkers. Standardised instruments will be used to ensure consistency and reliability in measuring persistent symptoms. Statistical analyses will include descriptive statistics, regression models and subgroup analyses to identify risk factors and the prevalence of post-COVID-19 syndrome.Ethics and dissemination The Human Research Ethics Committee of the Clinical Hospital of the University of Chile approved the study protocol (Memorandum No 007/2023). We will present the results in peer-reviewed publications and national and international professional and academic meetings.Trial registration number NCT05855382
Holocene glacier-climate history of the Calluqueo glacier and Monte San Lorenzo, central Patagonia
No full textWe present 33 new Be-10 exposure ages on boulders rooted in moraines in the Calluqueo valley in central Patagonia. The former glacier flowed westward off the Monte San Lorenzo massif and was expanded from similar to 6,900 until similar to 6,700 years ago; and at 5,620 +/- 200, 5,140 +/- 150, 4,660 +/- 180, 4,100 +/- 140, 3,610 +/- 200, 3,120 +/- 110 years ago (n=2 for these groups), and repeatedly during the last similar to 600 years. Glaciers may have advanced earlier in the Holocene, but additional effort is needed to elucidate the timing. Also taking into account a record in the nearby Tranquillo Valley, we see that at Monte San Lorenzo glaciers were expanded often between similar to 7 and similar to 3 ka, and after similar to 1.4 ka. During the middle Holocene moraines were built on average every similar to 500 years. The largest expansions of the last millennium were at similar to 1400-1500 CE. We also date boulders on the innermost moraine terrain to 1810 CE +/- 20 and 1870 CE +/- 20 years. A last phase of stability existed from similar to 1800 to 1940 CE, with pronounced ongoing retreat since after 1940 CE. The Monte San Lorenzo chronologies allow us to compare Holocene records between central and southernmost Patagonia. Throughout Patagonia, there is a similar glacier-climate history, with nested moraine sets and the largest glaciers generally in the mid-early Holocene. In most places, a marked change in glacier behavior and climate occurred around 7 ka, but some sites exhibit evidence of earlier Holocene activity. Over the last millennium, a net decrease in extent of advances occurred from similar to 1400 to similar to 1800 CE. However, there are some differences across Patagonia. In central Patagonia (similar to 44-49 degrees S), glaciers expanded between 4 and 3 ka, while from 3 to 2 ka moraines are not preserved; the pattern appears reversed to the south (i.e. south of similar to 49 degrees S). We hypothesize that Subantarctic or high latitude climates strongly impacted at least as far as northern Patagonia throughout the Holocene, including centennial and millennial changes in cold phases reflecting shifts in the Southern Hemisphere Westerlies and associated air masses. One exception perhaps is between 4 and 3 ka, where moraines are not observed to the south, possibly reflecting closer proximity to Antarctica where this interval may be generally warm. Regardless of secondary differences across southern South America, glacier records in central Patagonia are unlike those in the Northern Hemisphere, but similar to other records in the Southern Hemisphere. For comparison, anthropogenic climate change has caused climate, and thus glacier, behavior to be more in sync between the hemispheres, whereas longer-term Holocene records show distinct differences in histories even regionally within South America
Andrographolide modulates glucose metabolism in visceral adipose tissue in an Alzheimer's disease obese mouse model
No full textMidlife obesity and high adiposity are recognized as risk factors for Alzheimer's disease (AD), with visceral adipose tissue (VAT) playing a central role due to its endocrine and metabolic activity. Disturbances in VAT metabolism and adipokine secretion exacerbate AD pathology. Andrographolide (Andro), known for its anti-diabetic properties, enhances neuronal glucose uptake and alleviates AD pathology. However, its effects on VAT metabolism in AD remain unexplored. This study aimed to investigate the impact of Andro on glucose metabolism in VAT using a high-fat diet (HFD)-induced obesity model in AD mice (APP/PS1). APP/PS1 mice were fed an HFD and received Andro injections (2 mg/kg, three times a week for 16 weeks). VAT samples were analyzed for glucose uptake, glycolytic rate, pentose phosphate flux, ADP-ATP levels, gene expression, and enzymatic activity of glucose metabolic regulators. In APP/PS1 mice, HFD significantly increased glucose uptake and reduced GLUT4 expression in VAT, effects counteracted by Andro (p < 0.05). Andro-treated HFD-fed mice exhibited reduced glucose oxidation through glycolysis (p < 0.05), leading to decreased ATP production (p < 0.05). Andro administration restored the activity of key glycolytic enzymes and mitigated several HFD-induced metabolic alterations (p < 0.05). The study reveals significant metabolic changes in the VAT of obese APP/PS1 mice and highlights Andro's potential as a therapeutic agent for addressing VAT impairment induced by obesity in AD
Bridging the Scotia Arc: Climate-Driven Shifts in Connectivity of the Freshwater Crustacean Branchinecta gaini in Sub-Antarctic and Antarctic Ecosystems
No full textAimTo integrate the historical and contemporary connectivity of Branchinecta gaini (B. gaini), in order to better predict future distribution changes within its fragmented, dynamic and isolated habitat range.LocationThe study covers 20 locations of freshwater ecosystems across B. gaini distribution within the maritime Antarctic, sub-Antarctic South Georgia, Falkland/Malvinas Islands and southern South America (SSA).MethodsWe used two mitochondrial DNA loci and 7446 SNP markers to assess genetic diversity, population structure and connectivity of B. gaini. Additionally, we applied an ensemble ecological niche modelling (ENM) approach to project current and future species distributions under various climate scenarios.ResultsHigh genetic diversity was found in most sampled locations, with SSA exhibiting the greatest variation in terms of haplotype and nucleotide diversities. Antarctica exhibits short topologies with a limited number of shared haplotypes among its different regions. Overall, there is significant genetic and phylogeographic differentiation among biogeographic regions. Historical demographic analyses indicated population expansion in Antarctic regions but stability in SSA. Contemporary population structure analyses revealed six genetic clusters with limited gene flow and a clear pattern of isolation by distance. Ecological modelling suggested future habitat loss in the sub-Antarctic and potential expansion in Antarctic regions.Main ConclusionsOur integration of historical and contemporary connectivity potentially provides a solid foundation for the development of conservation strategies, especially in fragile areas with dramatic changes projected. The strong genetic structuring and limited connectivity of B. gaini across its range highlight the need for region-specific conservation strategies. These findings emphasise the importance of integrating genetic and ecological approaches to predict species' responses to environmental change and guide conservation strategies for vulnerable Antarctic freshwater ecosystems
Geomorphology, first 36Cl datings and chrono-evolutionary model of Mount Aragats paleoglaciers (Armenia)
No full textMount Aragats is one of the largest glaciated volcanoes of the Armenian Highlands (Rwlllwllwb lbnbwZruwnh) and culminating in the Aragats Peak, the highest peak of the Republic of Armenia (4090 masl). Here, prehistoric societies have been present for millennia, so assessing the local influence of past glaciations is a crucial factor to better understand the cultural evolution of this region. Therefore, this work focuses on a detailed study of the morphology and morphostratigraphic succession of Mount Aragats paleoglaciers. Geomorphic-based paleoglacier reconstruction along 36Cl cosmogenic dating (n = 13) of moraines reveal that during the Middle and Upper Pleistocene, a plateau glacier featuring ice lobes covered this area, featuring outlet lobes reaching up to 17 km in length, thicknesses of up to 350 m and descending to 2040 masl. According to the morphostratigraphic succession of ice-marginal features, absolute chronologies and regional correlations, the chronoevolutionary sequence of these glaciers comprises three intervals: (1) The absolute Maximum Ice Extent or Aragats Glacial Maximum occurred during the Penultimate Glacial Cycle within the MIS6e (c. 180 ka). (2) Subsequently, during the Last Glacial Cycle, the Maximum Ice Extent occurred during the MIS5d (c. 111 ka) followed by two secondary glacial maxima stabilizations during the MIS3a (c. 37 ka) and the MIS2 (c. 17 ka). Finally, (3) the Post-Glacial Period (PCP, Holocene, MIS1). The disappearance of the glaciers on Mount Aragats was established at the beginning of the second half of the 20th century by direct observations. The current morphodynamic environment corresponds to active rock glaciers, some neve` moraines and widespread activity of slope processes such as debris flow and debris slides
Inclusive parenting and occupational therapy: experiences and challenges from the South
No full textEste relato de experiencia analiza los desafíos y oportunidades que enfrentan mujeres con discapacidad en la region de Magallanes, Chile, al ejercer su parentalidad, basado en la sistematización de dos casos atendidos por la ONG REPRODIS. Entre los principales obstáculos se destacan el capacitismo, las barreras actitudinales y la falta de accesibilidad en los sistemas judiciales y de salud, los cuales limitan sus derechos y perpetúan discriminaciones estructurales. Desde un enfoque cualitativo y feminista situado, se exploran vivencias de mujeres que, pese a estas adversidades, luchan por su autonomía y el ejercicio pleno de su maternidad. La terapia ocupacional desempeña un rol clave en este proceso, ofreciendo intervenciones que fortalecen habilidades parentales, estructuran rutinas diarias y promueven la autodeterminación. Los resultados enfatizan la urgencia de políticas inclusivas que eliminen barreras y promuevan entornos accesibles. Asimismo, destacan el apoyo comunitario y profesional como elementos esenciales para garantizar la participación activa y efectiva de estas mujeres en la crianza de sus hijos
Interpretable and explainable predictive machine learning models for data-driven protein engineering
No full textProtein engineering through directed evolution and (semi)rational design has become a powerful approach for optimizing and enhancing proteins with desired properties. The integration of artificial intelligence methods has further accelerated protein engineering process by enabling the development of predictive models based on datadriven strategies. However, the lack of interpretability and transparency in these models limits their trustworthiness and applicability in real-world scenarios. Explainable Artificial Intelligence addresses these challenges by providing insights into the decision-making processes of machine learning models, enhancing their reliability and interpretability. Explainable strategies has been successfully applied in various biotechnology fields, including drug discovery, genomics, and medicine, yet its application in protein engineering remains underexplored. The incorporation of explainable strategies in protein engineering holds significant potential, as it can guide protein design by revealing how predictive models function, benefiting approaches such as machine learning-assisted directed evolution. This perspective work explores the principles and methodologies of explainable artificial intelligence, highlighting its relevance in biotechnology and its potential to enhance protein design. Additionally, three theoretical pipelines integrating predictive models with explainable strategies are proposed, focusing on their advantages, disadvantages, and technical requirements. Finally, the remaining challenges of explainable artificial intelligence in protein engineering and future directions for its development as a support tool for traditional protein engineering methodologies are discussed
Uso de llave de tres pasos como procedimiento de mantención de presiones seguras del cuff en pacientes adultos traqueostomizados: un estudio preliminar
No full textIn vitro models have shown that disconnecting the cuffometer from the pilot balloon of artificial airway devices generates pressure losses. This may contribute to the passage of content into the lower airway, which increases the risk of aspiration pneumonia. The aim of this project is to determine if the use of three-way stopcock valves prevents the loss of cuff pressures when disconnecting the cuffometer from the pilot balloon in adult tracheostomised patients. A descriptive, observational and cross-sectional study was performed, which included a total of 10 hospitalised and tracheostomised subjects between April and July 2024, at the Hospital San Juan de Dios, Santiago, Chile. Three-way stopcock valves, analogue and digital cuffometers were used during the measurement procedure of three pressures: 20, 30 and 25 cmH(2)O (P1, P2 and P3). The initial inflation pressures and final pressures upon disconnection of the analogue cuffometer were registered. For this research, non-significant p values were considered favourable. This is because no statistical difference between initial and final cuff pressure after the disconnection of the analogue cuffometer was expected. The project was approved by a Research Ethics Committee. For P1, there was an initial and final median pressure difference of .3 cmH(2)O; for P 2.5 cmH(2)O; and for P 3.0 cmH(2)O. There was no significant loss of cuff pressure when disconnecting the cuffometer from three-way stopcock valves. These valves could be effective for the management of patients with an artificial airway. It is mandatory to continue with this line of research
Studying the mechanisms of neurodegeneration: C. elegans advantages and opportunities
No full textCaenorhabditis elegans has been widely used as a model organism in neurodevelopment for several decades due to its simplicity, rapid growth, short life cycle, transparency, and rather simple genetics. It has been useful in modeling neurodegenerative diseases by the heterologous expression of the major proteins that form neurodegenerative-linked aggregates such as amyloid-beta peptide, tau protein, and alpha-synuclein, among others. Furthermore, chemical treatments as well as the existence of several interference RNA libraries, transgenic worm lines, and the possibility of generating new transgenic strains create a magnificent range of possible tools to study the signaling pathways that could confer protection against protein aggregates or, on the contrary, are playing a detrimental role. In this review, we summarize the different C. elegans models of neurodegenerative diseases with a focus on Alzheimer's and Parkinson's diseases and how genetic tools could be used to dissect the signaling pathways involved in their pathogenesis mentioning several examples. Finally, we discuss the use of pharmacological agents in C. elegans models that could help to study these disease-associated signaling pathways and the powerful combinations of experimental designs with genetic tools. This review highlights the advantages of C. elegans as a valuable intermediary between in vitro and mammalian in vivo models in the development of potential new therapies
Development of a physical literacy consensus statement for Chile: study protocol
No full textPhysical literacy is a multidimensional concept that encompasses various aspects of an individual's ability to engage in physical activities throughout their lifespan. As a holistic approach, physical literacy (PL) has generated a lot of interest in the field of physical education, physical activity, and health promotion. Despite its growing popularity, the conceptualization and understanding differ among the countries. In the case of Latin America, the concept of physical literacy is still relatively new and influenced different countries, making complex the contextualization for this region. Considering some aspects of public policies that seek to promote physical activity in Chile, such as the national policy of physical activity and sport or the curricular bases of the subject of physical education, this paper seeks to propose the systematized elaboration based on evidence to generate a contextualized consensus with the different actors that can contribute to the development of physical literacy in Chile. This protocol will involve mixed methods throughout the implementation of six work package processes: (1) review of the existing evidence about physical literacy for its understanding in Spanish-speaking populations, (2) analysis of drawings (preschoolers), semi-structured interviews (children, adolescents, and adults), and focus groups (older adults) to investigate the community's view of physical activity, (3) discussion groups and nationwide online questionnaire to analyze the understanding of the concept of PL by both physical education teachers and political actors, (4) discussion groups to consolidate community perceptions on the relevance of physical activity and physical literacy to prepare a preliminary consensus, (5) national consultation on the draft Physical Literacy Consensus Statement text, and (6) discussion and definition of the Physical Literacy Consensus Statement for Chile. This consensus will help stakeholders, teachers, researchers, and the community in general to understand a common concept of physical literacy, which will allow its development, promotion, and application in the Chilean context. Likewise, this work could be a spearhead to the implementation of physical literacy in Latin America and low-and middle-income countries in other regions. Clinical trial registration The clinical trial will be registered on ClinicalTrials.gov under the name CONALMOT_CL (COnsenso Nacional en ALfabetizaic MOTriz in Spanish: Physical Literacy National Consensus)