Search

Introducción. La salud auditiva es un tema de interés en salud pública que afecta la calidad de vida y que puede afectarse por la exposición continua al ruido, un factor de riesgo que genera síntomas auditivos y extraauditivos. Objetivo. Identificar el estado de salud auditiva de adultos que viven en Bogotá, y su asociación con factores de exposición a ruido ambiental, individuales y otológicos. Materiales y métodos. Se realizó un estudio transversal mediante el análisis de una base de datos con 10.311 registros, obtenidos entre los años 2014 y 2018, producto de una encuesta estructurada de percepción de ruido y tamizaje auditivo. Se hizo un análisis descriptivo bivariado y una regresión logística binaria. Resultados. El 35,4 % de los participantes presentó disminución auditiva. En el componente de percepción: 13,0 % refirió no escuchar bien, 28,8 % informó síntomas extraauditivos, 53,3 % tenía antecedentes otológicos, y 69,0 % manifestó molestia por ruido extramural. En la regresión logística, las variables más asociadas con disminución auditiva fueron: de las ambientales, vivir en zonas de mayor ruido (OR = 1,50) (IC95%: 1,34-1,69); de las individuales, ser hombre (OR = 1,85) (IC95%: 1,64-2,09) y la edad (por cada año de vida, el riesgo de disminución auditiva aumentó 6 %); y de las otológicas, tener antecedente de síntomas otológicos (OR = 1,86) (IC95%: 1,66-2,08). Conclusiones. La disminución auditiva es multicausal en la población evaluada. Los factores que aumentan su prevalencia son incremento de la edad, ser hombre, tabaquismo, medicamentos ototóxicos, vivir en zonas de mayor exposición a ruido y presentar síntomas extraauditivos.

Abstract Encephalitis is a rare and potentially fatal manifestation of herpes simplex type 1 infection. Following genome-wide genetic analyses, we identified a previously uncharacterized and very rare heterozygous variant in the E3 ubiquitin ligase WWP2, in a 14-month-old girl with herpes simplex encephalitis. The p.R841H variant (NM_007014.4:c.2522G > A) impaired TLR3 mediated signaling in inducible pluripotent stem cells-derived neural precursor cells and neurons; cells bearing this mutation were also more susceptible to HSV-1 infection compared to control cells. The p.R841H variant increased TRIF ubiquitination in vitro. Antiviral immunity was rescued following the correction of p.R841H by CRISPR-Cas9 technology. Moreover, the introduction of p.R841H in wild type cells reduced such immunity, suggesting that this mutation is linked to the observed phenotypes.

Abstract Background Alzheimer’s disease (AD) and amyotrophic lateral sclerosis/frontotemporal dementia (ALS/FTD) are debilitating neurodegenerative diseases for which there are currently no cures. Familial cases with known genetic causes make up less than 10% of these diseases, and little is known about the underlying mechanisms that contribute to sporadic disease. Accordingly, it is important to expand investigations into possible pathways that may contribute to disease pathophysiology. Glycerophosphodiester phosphodiesterase 2 (GDE2 or GDPD5) is a membrane-bound enzyme that acts at the cell surface to cleave the glycosylphosphatidylinositol (GPI)-anchor that tethers distinct proteins to the membrane. GDE2 abnormally accumulates in intracellular compartments in the brain of patients with AD, ALS, and ALS/FTD, indicative of GDE2 dysfunction. Mice lacking GDE2 (Gde2KO) show neurodegenerative changes such as neuronal loss, reduced synaptic proteins and synapse loss, and increased Aβ deposition, raising the possibility that GDE2 disruption in disease might contribute to disease pathophysiology. However, the effect of GDE2 loss on behavioral function and learning/memory has not been characterized. Results Here, we show that GDE2 is expressed throughout the adult mouse brain in areas including the cortex, hippocampus, habenula, thalamus, and amygdala. Gde2KO and WT mice were tested in a set of behavioral tasks between 7 and 16 months of age. Compared to WT, Gde2KO mice display moderate hyperactivity that becomes more pronounced with age across a variety of behavioral tests assessing novelty-induced exploratory activity. Additionally, Gde2KO mice show reduced startle response, with females showing additional defects in prepulse inhibition. No changes in anxiety-associated behaviors were found, but Gde2KOs show reduced sociability. Notably, aged Gde2KO mice demonstrate impaired short/long-term spatial memory and cued fear memory/secondary contextual fear acquisition. Conclusions Taken together, these observations suggest that loss of GDE2 leads to behavioral deficits, some of which are seen in neurodegenerative disease models, implying that loss of GDE2 may be an important contributor to phenotypes associated with neurodegeneration.

A conceptual design of coffee stem biomass gasification was developed using the Aspen Plus process simulator, which was analyzed based on energy criteria such as the lower heating value of the produced synthesis gas and cold gas efficiency. The results yielded a lower heating value of 5.07 kJ/MJ, with a cold gas efficiency of 77.45% and a yield of 2.75 kg gas/kg biomass, all operating under optimal conditions with studied parameters including an air-to-biomass ratio between 1.8 and 2.5, gasifying agent temperature of 260 °C, and biomass moisture content below 10%. A sensitivity analysis was conducted on the formation of the most important compounds for synthesis gas quality (H2, CO, CO2, H2O, CH4). This involved understanding the reactions occurring throughout the gasification reactor and evaluating process parameters such as feed moisture content, gasification section temperature, and the ratio between feed and gasifying agent flows to optimize the process with the aim of improving product quality and reducing residue formation. The simulation scheme was validated against experimental data, yielding results consistent with reality. This contributed valuable information towards process optimization for projects targeting the Colombian coffee sector, paving the way for future gasifier designs tailored to the quantity of raw material to be processed.

En Colombia son varios los humedales han experimentado cambios significativos en el espejo de agua, ya sea por procesos naturales o antrópicos; la mayoría de estos presentan eutrofización, hecho que se comprueba por la proliferación descontrolada de algas, herbáceas y juncáceas, haciéndolos vulnerables a fenómenos como el calentamiento global. Este estudio se centra en el humedal Torca – Guaymaral ubicado en el extremo norte de la ciudad de Bogotá (Colombia), el cual, actualmente se ve afectado por la rápida propagación de vegetación hidromórfica. Este ecosistema acuático es hábitat para innumerables especies, al mismo tiempo que brinda múltiples beneficios a la sociedad como humedal urbano. El análisis del área de estudio se realizó con base en la vegetación y la humedad en comparación con los datos arrojados por los índices NDVI y NDWI en los años 2014 y 2023 en los meses de enero y febrero respectivamente. Los mapas del humedal se realizan con el software ArcGIS para procesar imágenes satelitales Landsat 8-9, con un rango de nubosidad inferior al 60 % y descargadas de la plataforma USGS EarthExplorer. Los resultados indican la disminución de zonas húmedas en el Torca-Guaymaral en un 7.3 %, mientras que la escasez de vegetación aumentó un 12 %, se observó que la vegetación densa disminuyó en un 3 % y la vegetación moderada en un 9.24 %.

Background: Traumatic brain injury (TBI) is one of the top causes of disability in the younger population worldwide. Rehabilitation services should be accessible to all citizens to achieve universal health coverage. Objectives: This study aimed to explore the barriers and facilitators influencing the provision of rehabilitation for patients with TBI from occupational therapists’ perspectives in Gauteng, South African healthcare facilities. It further explored the perceived strategies that would strengthen the delivery and provision of TBI rehabilitation. Method: An exploratory qualitative research design was used in this study. A total of 16 occupational therapists were in focus groups either face-to-face or on an online platform. Thematic analysis was used to analyse the raw data. Results: There were three themes that emerged from the study, namely, ‘Not a recipe’, ‘Toolbox’, and ‘Lost in the cracks’. These themes highlighted the various aspects affecting the rehabilitation of patients with TBI. Conclusion: There are factors that both enhance and hinder service delivery for patients with TBI rehabilitation. Strategies to overcome barriers to TBI rehabilitation need to be considered to improve service provision for patients with TBI. Contribution: This article provides recommendations to improve occupational therapy services for patients with TBI in South Africa. The findings can contribute to policy development and education requirements for TBI.

IntroductionMost cases of Merkel cell carcinoma (MCC), a rare and highly aggressive type of neuroendocrine skin cancer, are associated with Merkel cell polyomavirus (MCPyV) infection. MCPyV integrates into the host genome, resulting in expression of oncoproteins including a truncated form of the viral large T antigen (LT) in infected cells. These oncoproteins are an attractive target for a therapeutic cancer vaccine.MethodsWe designed a cancer vaccine that promotes potent, antigen-specific CD4 T cell responses to MCPyV-LT. To activate antigen-specific CD4 T cells in vivo, we utilized our nucleic acid platform, UNITE™ (UNiversal Intracellular Targeted Expression), which fuses a tumor-associated antigen with lysosomal-associated membrane protein 1 (LAMP1). This lysosomal targeting technology results in enhanced antigen presentation and potent antigen-specific T cell responses. LTS220A, encoding a mutated form of MCPyV-LT that diminishes its pro-oncogenic properties, was introduced into the UNITE™ platform.ResultsVaccination with LTS220A-UNITE™ DNA vaccine (ITI-3000) induced antigen-specific CD4 T cell responses and a strong humoral response that were sufficient to delay tumor growth of a B16F10 melanoma line expressing LTS220A. This effect was dependent on the CD4 T cells’ ability to produce IFNγ. Moreover, ITI-3000 induced a favorable tumor microenvironment (TME), including Th1-type cytokines and significantly enhanced numbers of CD4 and CD8 T cells as well as NK and NKT cells. Additionally, ITI-3000 synergized with an α-PD-1 immune checkpoint inhibitor to further slow tumor growth and enhance survival.ConclusionsThese findings strongly suggest that in pre-clinical studies, DNA vaccination with ITI-3000, using the UNITE™ platform, enhances CD4 T cell responses to MCPyV-LT that result in significant anti-tumor immune responses. These data support the initiation of a first-in-human (FIH) Phase 1 open-label study to evaluate the safety, tolerability, and immunogenicity of ITI-3000 in patients with polyomavirus-positive MCC (NCT05422781).

Summary: Intradermal delivery of self-replicating RNA (srRNA) is a promising vaccine platform. We have developed an srRNA that functions optimally at around 33°C (skin temperature) and is inactivated at or above 37°C (core body temperature) as a safety switch. This temperature-controllable srRNA (c-srRNA), when tested as an intradermal vaccine against SARS-CoV-2, functions when injected naked without lipid nanoparticles. Unlike most currently available vaccines, c-srRNA vaccines predominantly elicit cellular immunity with little or no antibody production. Interestingly, c-srRNA-vaccinated mice produced antigen-specific antibodies upon subsequent stimulation with antigen protein. Antigen-specific antibodies were also produced when B cell stimulation using antigen protein was followed by c-srRNA booster vaccination. We have thus designed a pan-coronavirus booster vaccine that incorporates both spike-receptor-binding domains as viral surface proteins and evolutionarily conserved nucleoproteins as viral internal proteins, from both severe acute respiratory syndrome coronavirus 2 and Middle East respiratory syndrome coronavirus. c-srRNA may provide a route to activate cellular immunity against a wide variety of pathogens.

mRNA vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have played a key role in reducing morbidity and mortality from coronavirus disease 2019 (COVID-19). We conducted a double-blind, placebo-controlled phase I/II trial to evaluate the safety, tolerability, and immunogenicity of EXG-5003, a two-dose, controllable self-replicating RNA vaccine against SARS-CoV-2. EXG-5003 encodes the receptor binding domain (RBD) of SARS-CoV-2 and was administered intradermally without lipid nanoparticles (LNPs). The participants were followed for 12 months. Forty healthy participants were enrolled in Cohort 1 (5 µg per dose, n = 16; placebo, n = 4) and Cohort 2 (25 µg per dose, n = 16; placebo, n = 4). No safety concerns were observed with EXG-5003 administration. SARS-CoV-2 RBD antibody titers and neutralizing antibody titers were not elevated in either cohort. Elicitation of antigen-specific cellular immunity was observed in the EXG-5003 recipients in Cohort 2. At the 12-month follow-up, participants who had received an approved mRNA vaccine (BNT162b2 or mRNA-1273) >1 month after receiving the second dose of EXG-5003 showed higher cellular responses compared with equivalently vaccinated participants in the placebo group. The findings suggest a priming effect of EXG-5003 on the long-term cellular immunity of approved SARS-CoV-2 mRNA vaccines.

BackgroundThe use of circulating cDC1 to generate anti-cancer vaccines is among the most promising approaches to overcome the limited immunogenicity and clinical efficacy of monocyte-derived DC. However, the recurrent lymphopenia and the reduction of DC numbers and functionality in patients with cancer may represent an important limitation of such approach. In patients with ovarian cancer (OvC) that had received chemotherapy, we previously showed that cDC1 frequency and function were reduced.MethodsWe recruited healthy donors (HD, n=7) and patients with OvC at diagnosis and undergoing interval debulking surgery (IDS, n=6), primary debulking surgery (PDS, n=6) or at relapse (n=8). We characterized longitudinally phenotypic and functional properties of peripheral DC subsets by multiparametric flow cytometry.ResultsWe show that the frequency of cDC1 and the total CD141+ DC capacity to take up antigen are not reduced at the diagnosis, while their TLR3 responsiveness is partially impaired in comparison with HD. Chemotherapy causes cDC1 depletion and increase in cDC2 frequency, but mainly in patients belonging to the PDS group, while in the IDS group both total lymphocytes and cDC1 are preserved. The capacity of total CD141+ DC and cDC2 to take up antigen is not impacted by chemotherapy, while the activation capacity upon Poly(I:C) (TLR3L) stimulation is further decreased.ConclusionsOur study provides new information about the impact of chemotherapy on the immune system of patients with OvC and sheds a new light on the importance of considering timing with respect to chemotherapy when designing new vaccination strategies that aim at withdrawing or targeting specific DC subsets.

Debido a la pandemia del COVID-19 los mandatarios a nivel internacional a través de la administración actuaron de una manera atípica debido a la emergencia sanitaria. Gracias a esta situación, se gestó la contratación de emergencia sanitaria pública en Colombia y España, con el objetivo de recuperar la economía y contener el contagio del virus. En consecuencia, se afectó la reglamentación de la figura normativa del anticipo en España en los contratos celebrados por las instituciones públicas, mientras que en Colombia no se alteró, es por esto que, el presente artículo se realizó por medio del método cualitativo-descriptivo, en el cual se identificaron los cambios sustanciales que sufrieron las normativas, al generar estas contrataciones de emergencia y como establecieron excepciones por los mismos gobiernos como resultado de la aplicación de nuevas normas jurídicas. Por ende, pretendemos dar respuesta a la siguiente pregunta ¿Cuáles fueron los cambios normativos más importantes derivados de la pandemia sobre el anticipo en Colombia y España y su relación con la corrupción? . De acuerdo con el análisis realizado, se toman en cuenta casos de corrupción de la contratación pública y los anticipos, se determinó que el mal manejo de la figura ha desencadenado, varios hechos relevantes donde se produce este fenómeno, sin embargo, no es el generador absoluto de la problemática. En cuanto al comparativo entre los países, se identifica que Colombia utiliza el anticipo con mayor proporción, contrario sensu a lo establecido en España, incluso antes de la pandemia.

Copyright of Biomédica: Revista del Instituto Nacional de Salud is the property of Instituto Nacional de Salud of Colombia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Summary: Mutations of SHANK3 cause Phelan-McDermid syndrome (PMS), and these individuals can exhibit sensitivity to stress, resulting in behavioral deterioration. Here, we examine the interaction of stress with genotype using a mouse model with face validity to PMS. In Shank3ΔC/+ mice, swim stress produces an altered transcriptomic response in pyramidal neurons that impacts genes and pathways involved in synaptic function, signaling, and protein turnover. Homer1a, which is part of the Shank3-mGluR-N-methyl-D-aspartate (NMDA) receptor complex, is super-induced and is implicated in the stress response because stress-induced social deficits in Shank3ΔC/+ mice are mitigated in Shank3ΔC/+;Homer1a−/− mice. Several lines of evidence demonstrate that Shank3 expression is regulated by Homer1a in competition with crosslinking forms of Homer, and consistent with this model, Shank3 expression and function that are reduced in Shank3ΔC/+ mice are rescued in Shank3ΔC/+;Homer1a−/− mice. Studies highlight the interaction between stress and genetics and focus attention on activity-dependent changes that may contribute to pathogenesis.

Abstract Background Several mechanisms are present in the tumor microenvironment (TME) to impair cytotoxic T cell responses potentially able to control tumor growth. Among these, the accumulation of adenosine (Ado) contributes to tumor progression and represents a promising immunotherapeutic target. Ado has been shown to impair T cell effector function, but the role and mechanisms employed by Ado/Ado receptors (AdoRs) in modulating human peripheral and tumor-infiltrating lymphocyte (TIL) function are still puzzling. Methods CD8+ T cell cytokine production following stimulation was quantified by intracellular staining and flow cytometry. The cytotoxic capacity of tumor infiltrating lymphocytes (TILs) was quantified by the chromium release assay following co-culture with autologous or anti-CD3-loaded tumor cell lines. The CD8+ T cell metabolic fitness was evaluated by the seahorse assay and by the quantification of 2-NBDG uptake and CD71/CD98 upregulation upon stimulation. The expression of AdoRs was assessed by RNA flow cytometry, a recently developed technology that we validated by semiquantitative RT-PCR (qRT-PCR), while the impact on T cell function was evaluated by the use of selective antagonists and agonists. The influence of Ado/AdoR on the PKA and mTOR pathways was evaluated by phosphoflow staining of p-CREB and p-S6, respectively, and validated by western blot. Results Here, we demonstrate that Ado signaling through the A2A receptor (A2AR) in human peripheral CD8+ T cells and TILs is responsible for the higher sensitivity to Ado-mediated suppression of T central memory cells. We confirmed that Ado is able to impair peripheral and tumor-expanded T cell effector functions, and we show for the first time its impact on metabolic fitness. The Ado-mediated immunosuppressive effects are mediated by increased PKA activation that results in impairment of the mTORC1 pathway. Conclusions Our findings unveil A2AR/PKA/mTORC1 as the main Ado signaling pathway impairing the immune competence of peripheral T cells and TILs. Thus, p-CREB and p-S6 may represent useful pharmacodynamic and efficacy biomarkers of immunotherapies targeting Ado. The effect of Ado on T cell metabolic fitness reinforces the importance of the adenosinergic pathway as a target for next-generation immunotherapy.

Background: Estimating morbidity outcomes and the rate of progression of chronic kidney disease (CKD) patients is of great importance for the health systems. Objective: The objective of this study is to estimate the incidence of dialysis initiation and the rate of CKD progression in 2 years follow-up and identify factors associated with dialysis starts. Methods: A retrospective cohort study of adult with diagnosed CKD stages-G3, G4 (estimated glomerular filtration rate between 60 and 15 ml/min/1.73 m2) enrolled into a CKD prevention program in Bogotá-Colombia, since January 1, 2016, to June 30, 2017, with follow-up until June 30, 2019. Cohort’s outcomes were arrival to dialysis and stage G5, dropout of the program, hospitalization, and mortality. Repeated measurements of the estimation of glomerular filtration rate (eGFR) allowed us to estimate the change over time in 4-month periods using a mixed-effects model. An Extended Cox model was adjusted for the time to start dialysis. Results: One thousand four hundred forty-eight patients were included in the analysis; the incidence rate of dialysis initiation was 2.1 events per 100 patients-year (95% CI: 1.5 2.7). The mean of eGFR variation was +1.1 ml/min/1.73 m2/year; and for diabetics was −1.0 ml/min/m2/year. Being diabetic and having poorly controlled hypertension were significant risk factors for time to dialysis initiation. Conclusion: The incidence rates of dialysis initiation, dropout, and hospitalization are outcomes of significant interest in a CKD prevention program. Being diabetic and poor blood pressure control are risk factors for a more rapid progression to dialysis.

A 17-year-old student athlete suffering from stress-related knee pain asked for help. MRI revealed an unstable osteochondral lesion. Because of time pressure due to the patient’s academic exams and his schedule as a basketball player, an autologous chondrocyte transplantation (ACT) as the standard surgical treatment plan was not accepted by the patient. This was mainly because of its two-step character three weeks in between surgeries. Therefore, a surgical one-step therapy option as alternative treatment to ACT was needed. The patient received simultaneous autologous cancellous bone grafting and minced cartilage procedure in a sandwich technique. After successful rehabilitation, the patient continued his studies of sports science and his active career as a basketball player successfully. Several different procedures are used for the treatment of cartilage defects. The following factors play a significant role: defect size, location, patient age, and sports ambitions. In the case described here, ACT would have been the conventional, but not the ideal option in the perspective of this individual patient because of the two-step surgery and the longer rehabilitation time. Therefore, the minced cartilage method presented a valid alternative, even though long-term data are still missing and prospective studies comparing this procedure with others are needed in the future.

El artículo se centra en las estrategias didácticas de enseñar a enseñar y enseñar a aprender, dirigidas a favorecer el proceso de evaluación del aprendizaje en la formación pedagógica superior y en el contexto educativo de la escuela primaria. Se describe la metodología propuesta para la implementación de dichas estrategias y los resultados obtenidos con su aplicación, tales como una mejor orientación de los alumnos hacia las tareas de aprendizaje, la incorporación de todos los docentes en formación y alumnos de la escuela primaria implicados en los análisis de los resultados mediante la auto y coevaluación; en todos los casos se evidenció un movimiento favorable entre los rangos de 3 a 5. Para realizar la investigación que constituye la génesis de este artículo se utilizaron métodos empíricos y teóricos que corroboraron la necesidad de perfeccionar la evaluación del aprendizaje de los escolares primarios, desde la implementación de las estrategias de referencia. Las escalas valorativas sobre el análisis de la evaluación en los diferentes momentos de la actividad de aprendizaje se fundamentan en los resultados de los análisis exploratorios, la interpretación de instrumentos de evaluación aplicados y en la sistematización de algunas fuentes teóricas.

Background: pterygium is a tumoral lesion of benign behavior and multifactorial ethiology, where conjunctive proliferates with fibro vascular growing and it invades cornea in warmer climates. It can be primary or recidivant and according to the level that reaches the corneal invasion four grades are described. It is a mass of subepitelial tissue with elastotic degeneration, on a bottom of hyaline degeneration, new blood vessels and inflammatory changes, the epithelium that covers it can show acanthosis, dyskeratosis and dysplasia. Taking into account these characteristics, it is classified as angiomatous, fibrous and mixed. Objective: to identify clinical and histopathologic characteristics in operated patients of primary pterygium. Methods: a descriptive, transverse study was carried out in the Educational Surgical Hospital Dr. Octavio de la Concepción y de la Pedraja in Camagüey from September to December 2016. The universe was constituted by 77 operated patients. Variables of biological and clinical characterization were related. Descriptive statistics for distribution of frequencies correlating the variables with absolute values and percents was used. Ethical aspects were respected for investigation in humans. Results: the biggest number of sick persons was among 40 to 59 years of age, and those studied were white. According to the grade of corneal invasion the biggest frequencies were for grade III, followed by grade II and grade IV. In the examined samples epithelial hyperplasia was informed, hyaline and elastotic degeneration, slight dysplasia, vascular structures associated or not to other fibrous changes, chaliciforms cells in the epithelium, chronic inflammation and deposit of pigments. Pterygium of fibrous type prevailed over the fibrous one and on the angiomatous. Conclusions: keeping in mind that the pterigion is an illness that impacts with great frequency in the Cuban population, the study of its clinical and histopathologic characteristics is vital for good ophthalmologic practices The result of the histopathologic study was similar to those described by other authors. Its histopathology continues showing as a benign tissue of the conjunctiva. DeCS: PTERYGIUM; CORNEAL DISEASES; PATHOLOGY; ADULT; EPIDEMIOLOGY, DESCRIPTIVE.

Background. Acid-base disorders have been previously described in patients with chronic hemodialysis, with metabolic acidosis being the most important of them; however, little is known about the potential changes in acid-base status of patients on dialysis living at high altitudes. Methods. Cross-sectional study including 93 patients receiving chronic hemodialysis on alternate days and living in Bogotá, Colombia, at an elevation of 2,640 meters (8,661 feet) over sea level (m.o.s.l.). Measurements of pH, PaCO2, HCO3, PO2, and base excess were made on blood samples taken from the arteriovenous fistula (AVF) during the pre- and postdialysis periods in the midweek hemodialysis session. Normal values for the altitude of Bogotá were taken into consideration for the interpretation of the arterial blood gases. Results. 43% (n= 40) of patients showed predialysis normal acid-base status. The most common acid-base disorder in predialysis period was metabolic alkalosis with chronic hydrogen ion deficiency in 19,3% (n=18). Only 9,7% (n=9) had predialysis metabolic acidosis. When comparing pre- and postdialysis blood gas analysis, higher postdialysis levels of pH (7,41 versus 7,50, p

Resumen. En la Reserva Forestal Protectora Bosques de la CHEC, ubicada sobre la vertiente occidental de la cordillera central colombiana, municipios de Manizales y Villamaría, departamento de Caldas, se hizo la caracterización física, química y mineralógica de dos perfiles de suelos, descritos sobre dos laderas, con un manejo actual correspondiente a una plantación de aliso (Alnus acuminata) y un bosque secundario. Los resultados permitieron establecer,desde el punto de vista físico, el dominio de clase textural areno francosa en la plantación de aliso y franco arenoso en el bosque secundario. Químicamente el suelo del perfil plantado con aliso, presentó valores de pH más bajos, mayor saturación de acidez intercambiable y menor saturación de bases en comparación con el perfil del bosque secundario. En ambos perfiles, el análisis óptico con microscopio petrográfico, permitió observar que los feldespatos, del grupo de las plagioclasas y el vidrio volcánico, se destacan como minerales abundantes en la fracción arena; mientras que en la fracción arcilla, el material no cristalino, seconsidera mineral predominante, seguido de la cristobalita y los feldespatos, según la metodología de difracción de rayos X. Se concluye que la vocación de uso forestal protector, bajo el cual se encuentran sometidos ambos suelos, es el más adecuado, teniendo en cuenta que las limitaciones químicas, dificultan el establecimiento de sistemas de producción agropecuaria. / Abstract. The physical, chemical and mineralogical characterization of two soil profiles on two slopes, with a management currently corresponding to an Andean alder plantation (Alnus acuminata) and a secondary forest, was carried out at the Protective Forest Reserve of the CHEC. This reserve is located on the western slope of the Central Mountain Range of the Colombian Andes, in the municipalities of Manizales and Villamaria, Caldas Department. The results established a dominance of the sandy - loam texturalclass in the alder plantation, and the loamy-sand class in the secondary forest. Chemically, the soil profile of the alder plantation presented lower pH values, a higher saturation of exchangeable acidity, and a lower saturation of bases in comparison to the secondary forest’s soil profile. In both profiles, the optical analysis by petrographic microscopy determined that feldspars, as a part of the plagioclase and volcanic glass group, stand out as abundant minerals in the sandy fraction. Meanwhile, in the clay fraction, the non-crystalline material is considered a predominant mineral, followed by cristobalite and feldspars, according to X-ray diffraction methods. The vocational protective forest use on both sites is the most adequate, taking into account that chemical limitations hinder the establishment of agricultural production systems.