Publications by authors named "S Castro"

1,374 Publications

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Structural Features of the Human Connectome That Facilitate the Switching of Brain Dynamics via Noradrenergic Neuromodulation.

Front Comput Neurosci 2021 14;15:687075. Epub 2021 Jul 14.

Instituto Milenio Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile.

The structural connectivity of human brain allows the coexistence of segregated and integrated states of activity. Neuromodulatory systems facilitate the transition between these functional states and recent computational studies have shown how an interplay between the noradrenergic and cholinergic systems define these transitions. However, there is still much to be known about the interaction between the structural connectivity and the effect of neuromodulation, and to what extent the connectome facilitates dynamic transitions. In this work, we use a whole brain model, based on the Jasen and Rit equations plus a human structural connectivity matrix, to find out which structural features of the human connectome network define the optimal neuromodulatory effects. We simulated the effect of the noradrenergic system as changes in filter gain, and studied its effects related to the global-, local-, and meso-scale features of the connectome. At the global-scale, we found that the ability of the network of transiting through a variety of dynamical states is disrupted by randomization of the connection weights. By simulating neuromodulation of partial subsets of nodes, we found that transitions between integrated and segregated states are more easily achieved when targeting nodes with greater connection strengths-local feature-or belonging to the rich club-meso-scale feature. Overall, our findings clarify how the network spatial features, at different levels, interact with neuromodulation to facilitate the switching between segregated and integrated brain states and to sustain a richer brain dynamics.
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http://dx.doi.org/10.3389/fncom.2021.687075DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8316621PMC
July 2021

Targeting redox metabolism of the maize-Azospirillum brasilense interaction exposed to arsenic-affected groundwater.

Physiol Plant 2021 Jul 30. Epub 2021 Jul 30.

Instituto de Investigaciones Agrobiotecnológicas - Consejo Nacional de Investigaciones Científicas y Técnicas (INIAB-CONICET), Departamento de Ciencias Naturales, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto (UNRC), Córdoba, Argentina.

Arsenic in groundwater constitutes an agronomic problem due to its potential accumulation in the food chain. Among the agro-sustainable tools to reduce metal(oid)s toxicity, the use of Plant Growth-Promoting Bacteria (PGPB) becomes important. For that, and based on previous results in which significant differences of As translocation were observed when inoculating maize plants with Az39 or CD Azospirillum strains, we decided to decipher the redox metabolism changes and the antioxidant system response of maize plants inoculated when exposed to a realistic arsenate (As ) dose. Results showed that As caused morphological changes in the root exodermis. Photosynthetic pigments decreased only in CD inoculated plants, while oxidative stress evidence was detected throughout the plant, regardless of the assayed strain. The antioxidant response was strain-differential since only CD inoculated plants showed an increase in superoxide dismutase, glutathione S-transferase (GST) and glutathione reductase (GR) activities while other enzymes showed the same behaviour irrespective of the inoculated strain. Gene expression assays reported that only GST23 transcript level was upregulated by arsenate, regardless of the inoculated strain. As diminished the glutathione (GSH) content of roots inoculated with the Az39 strain, and CD inoculated plants showed a decrease of oxidized GSH(GSSG) levels. We suggest a model in which the antioxidant response of the maize-diazotrophs system is modulated by the strain and that GSH plays a central role acting mainly as a substrate for GST. These findings generate knowledge for a suitable PGPB selection, and its scaling to an effective bioinoculant formulation for maize crops exposed to adverse environmental conditions.
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http://dx.doi.org/10.1111/ppl.13514DOI Listing
July 2021

Derivation and validation of a national multicenter mortality risk stratification model - the ExCare model: a study protocol.

Braz J Anesthesiol 2021 Jul 26. Epub 2021 Jul 26.

Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.

Introduction: Surgical care is essential for proper management of various diseases. However, it can result in unfavorable outcomes. In order to identify patients at higher risk of complications, several risk stratification models have been developed. Ideally, these tools should be simple, reproducible, accurate, and externally validated. Unfortunately, none of the best-known risk stratification instruments have been validated in Brazil. In this sense, the Ex-Care model was developed by retrospective data analysis of surgical patients in a major Brazilian university hospital. It consists of four independent predictors easily collected in the preoperative evaluation, showing high accuracy in predicting death within 30 days after surgery.

Objectives: To update and validate a Brazilian national-based model of postoperative death probability within 30 days based on the Ex-Care model. Also, to develop an application for smartphones that allows preoperative risk stratification by Ex-Care model.

Methods: Ten participating centers will collect retrospective data from digital databases. Variables age, American Society of Anesthesiology (ASA) physical status, surgical severity (major or non-major) and nature (elective or urgent) will be evaluated as predictors for in-hospital mortality within 30 postoperative days, considered the primary outcome.

Expected Results: We believe that the Ex-Care model will present discriminative capacity similar to other classically used scores validated for surgical mortality prediction. Furthermore, the mobile application to be developed will provide a practical and easy-to-use tool to the professionals enrolled in perioperative care.
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http://dx.doi.org/10.1016/j.bjane.2021.07.003DOI Listing
July 2021

Relationship between the sociodemographic characteristics of participants in the DIADA project and the rate of compliance with follow-up assessments in the initial stage of the intervention.

Rev Colomb Psiquiatr (Engl Ed) 2021 Jul 20. Epub 2021 Jul 20.

Departamento de Epidemiología Clínica y Bioestadística, Facultad de Medicina, Pontificia Universidad Javeriana, Bogotá, Colombia; Departamento de Psiquiatría y Salud Mental, Facultad de Medicina, Pontificia Universidad Javeriana, Bogotá, Colombia; Hospital Universitario San Ignacio, Bogotá, Colombia.

Objective: Analyse the relationship between the sociodemographic profile of the DIADA study participants and the rate of compliance with the follow-up assessments in the early stage of this project's intervention for depression and unhealthy alcohol use offered within primary care.

Methods: A non-experimental quantitative analysis was conducted. The sociodemographic data of DIADA [Detección y Atención Integral de Depresión y Abuso de Alcohol en Atención Primaria (Detection and Integrated Care for Depression and Alcohol Use in Primary Care)] study participants had been previously collected. At the time of the evaluation (September 12, 2019), only the participants who had been in the project for a minimum of 3 months were included. By using univariate (Chi-squared) analyses, we studied the association between participants' sociodemographic profile and their rate of compliance with the first follow-up assessment at 3 months after study initiation.

Results: At the date of the evaluation, 584 adult participants were identified, of which 389 had been involved in the project for more than 3 months. From the participants included, 320 performed the first follow-up, while 69 did not. The compliance rate to the first follow-up was 82.3% (95 % [CI] 78.1%-86%) and was not affected by: site location, age, sex, civil status, level of education, use of smartphone, PHQ9 score (measuring depression symptomatology) or AUDIT score (measuring harmful alcohol use). Participants who do not use a smartphone, from rural areas and with a lower socioeconomic status, tended to show higher compliance rates. Statistically significant associations were found; participants with lower job stability and a lack of access to the Internet showed higher compliance rates to the early initial follow-up assessment.

Conclusions: The compliance rate was high and generally constant in spite of the variability of the sociodemographic profiles of the participants, although several sub-groups of participants showed particularly high rates of compliance. These findings may suggest that integrating mental health into primary care allows the structural and financial barriers that hinder access to health in Colombia to be broken down by raising awareness about mental illnesses, their high prevalence and the importance of timely and accessible medical management.
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http://dx.doi.org/10.1016/j.rcpeng.2021.06.006DOI Listing
July 2021

Barriers and facilitators to the diagnosis and treatment of depression in primary care in Colombia: Perspectives of providers, healthcare administrators, patients and community representatives.

Rev Colomb Psiquiatr (Engl Ed) 2021 Jul 16. Epub 2021 Jul 16.

Center for Technology and Behavioral Health, Geisel School of Medicine, Dartmouth College, Lebanon, NH, USA.

Introduction: Depression represents a major disease burden in Colombia. To better understand opportunities to improve access to mental healthcare in Colombia, a research team at Javeriana University conducted formative qualitative research to explore stakeholders' experiences with the integration of mental healthcare into the primary care system.

Methods: The research team conducted 16 focus groups and 4 in-depth interviews with patients, providers, health administrators and representatives of community organisations at five primary care clinics in Colombia, and used thematic analysis to study the data.

Results: Themes were organised into barriers and facilitators at the level of patients, providers, organisations and facilities. Barriers to the treatment of depression included stigma, lack of mental health literacy at the patient and provider level, weak links between care levels, and continued need for mental health prioritization at the national level. Facilitators to the management of depression in primary care included patient support systems, strong patient-provider relationships, the targeting of depression interventions and national depression guidelines.

Discussion: This study elucidates the barriers to depression care in Colombia, and highlights action items for further integrating depression care into the primary care setting.
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http://dx.doi.org/10.1016/j.rcpeng.2021.01.001DOI Listing
July 2021
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