Helminth egg derivatives as proregenerative immunotherapies.

The immune system is increasingly recognized as an important regulator of tissue repair. We developed a regenerative immunotherapy from the helminth Schistosoma mansoni soluble egg antigen (SEA) to stimulate production of interleukin (IL)-4 and other type 2-associated cytokines without negative infection-related sequelae. The regenerative SEA (rSEA) applied to a murine muscle injury induced accumulation of IL-4-expressing T helper cells, eosinophils, and regulatory T cells and decreased expression of IL-17A in gamma delta (γδ) T cells, resulting in improved repair and decreased fibrosis. Encapsulation and controlled release of rSEA in a hydrogel further enhanced type 2 immunity and larger volumes of tissue repair. The broad regenerative capacity of rSEA was validated in articular joint and corneal injury models. These results introduce a regenerative immunotherapy approach using natural helminth derivatives.

Characterization of Tensioned PDMS Membranes for Imaging Cytometry on Microraft Arrays.

Polydimethylsiloxane (PDMS) membranes can act as sensing elements, barriers, and substrates, yet the low rigidity of the elastomeric membranes can limit their practical use in devices. Microraft arrays rely on a freestanding PDMS membrane as a substrate for cell arrays used in imaging cytometry and cellular isolation. However, the underlying PDMS membrane deforms under the weight of the cell media, making automated analytical microscopy (and thus cytometry and cell isolation) challenging. Here we report the development of microfabrication strategies and physically motivated mathematical modeling of membrane deformation of PDMS microarrays. Microraft arrays were fabricated with mechanical tension stored within the PDMS substrate. These membranes deformed 20× less than that of arrays fabricated using prior methods. Modeling of the deformation of pretensioned arrays using linear membrane theory yielded ≤15% error in predicting the array deflection and predicted the impact of cure temperatures up to 120 °C. A mathematical approach was developed to fit models of microraft shape to sparse real-world shape measurements. Automated imaging of cells on pretensioned microarrays using the focal planes predicted by the model produced high quality fluorescence images of cells, enabling accurate cell area quantification (<4% error) at increased speed (13×) relative to conventional methods. Our microfabrication method and simplified, linear modeling approach is readily applicable to control the deformation of similar membranes in MEMs devices, sensors, and microfluidics.

Shape memory activation can affect cell seeding of shape memory polymer scaffolds designed for tissue engineering and regenerative medicine.

The ability of a three-dimensional scaffold to support cell seeding prior to implantation is a critical criterion for many scaffold-based tissue engineering and regenerative medicine strategies. Shape memory polymer functionality may present important new opportunities and challenges in cell seeding, but the extent to which shape memory activation can positively or negatively affect cell seeding has yet to be reported. The goal of this study was to determine whether shape memory activation can affect cell seeding. The hypothesis was that shape memory activation of porous scaffolds during cell seeding can affect both the number of cells seeded in a scaffold and the distribution (in terms of average infiltration distance) of cells following seeding. Here, we used a porous shape memory foam scaffold programmed to expand when triggered to study cell number and average cell infiltration distance following shape memory activation. We found that shape memory activation can affect both the number of cells and the average cell infiltration distance. The effect was found to be a function of rate of shape change and scaffold pore interconnectivity. Magnitude of shape change had no effect. Only reductions in cell number and infiltration distance (relative to control and benchmark) were observed. The findings suggest that strategies for tissue engineering and regenerative medicine that involve shape memory activation in the presence of a cell-containing medium in vitro or in vivo should consider how recovery rate and scaffold pore interconnectivity may ultimately impact cell seeding.

Improving translation initiation site and stop codon recognition by using more than two classes.

MOTIVATION: The recognition of translation initiation sites and stop codons is a fundamental part of any gene recognition program. Currently, the most successful methods use powerful classifiers, such as support vector machines with various string kernels. These methods all use two classes, one of positive instances and another one of negative instances that are constructed using sequences from the whole genome. However, the features of the negative sequences differ depending on the position of the negative samples in the gene. There are differences depending on whether they are from exons, introns, intergenic regions or any other functional part of the genome. Thus, the positive class is fairly homogeneous, as all its sequences come from the same part of the gene, but the negative class is composed of different instances. The classifier suffers from this problem. In this article, we propose the training of different classifiers with different negative, more homogeneous, classes and the combination of these classifiers for improved accuracy. RESULTS: The proposed method achieves better accuracy than the best state-of-the-art method, both in terms of the geometric mean of the specificity and sensitivity and the area under the receiver operating characteristic and precision recall curves. The method is tested on the whole human genome. The results for recognizing both translation initiation sites and stop codons indicated improvements in the rates of both false-negative results (FN) and false-positive results (FP). On an average, for translation initiation site recognition, the false-negative ratio was reduced by 30.2% and the FP ratio decreased by 10.9%. For stop codon prediction, FP were reduced by 41.4% and FN by 31.7%. AVAILABILITY AND IMPLEMENTATION: The source code is licensed under the General Public License and is thus freely available. The datasets and source code can be obtained from http://cib.uco.es/site-recognition. CONTACT: npedrajas@uco.es.

What Is the Likely Impact of Alternative Proteins on Diet Quality, Health, and the Environment in Low- and Middle-Income Countries.

Alternative protein (AP) foods are proposed to support a global protein transition. Whereas AP food innovation has been a strategy to promote consumption of protein sources with low environmental impact in high-income countries (HICs) diets, their relation to sustainable, high-quality diets in low- and middle-income countries (LMICs) remains to be established. AP foods vary in nutrient profile, processing requirements, costs, and environmental impact. Current literature regarding AP suitability in LMIC contexts is limited. This perspective examined environmental and nutritional metrics that can assess the sustainability of AP in LMICs. Current research areas needed to accurately assess environmental impacts while considering nutritional density were identified. An overview of the usability of relevant AP in both high- and low-resource settings was also explored. Metrics addressing diverse contextual synergies in LMICs, unifying nutritional, environmental, and socioeconomic considerations, were found necessary to guide the integration of AP into LMIC diets.

Suitability of Alternative Protein Foods for Agroecological Approaches to Address Nutrition in Low- and Middle-Income Countries.

Agroecology has been proposed as a holistic approach to transform food systems that meet global food requirements with favorable environmental and social impacts. Agroecology relies on science, practices, and social movements that emphasize ecological principles, local knowledge, culture, and traditions to increase the sustainability and equity of the food system. Agroecological practices have demonstrated positive outcomes on food security and nutrition in low- and middle-income countries (LMICs). Agroecology principles can be applied across the food system and could facilitate the integration of certain alternative protein (AP) foods to address multiple issues. In this perspective, agroecological principles were analyzed to compare the suitability of different AP sources: unprocessed/minimally processed legumes, plant-based meats, edible insects, macroalgae (seaweed), fungal biomass, and cultivated meat. Considerations were identified for the feasibility of AP adoption in LMICs within an agroecological framework to provide nutrient-rich and sustainable diets while addressing other principles such as fairness and economic diversity. From this analysis, legumes, simplified plant-based meat analogs such as texturized plant proteins with minimal additives, edible insects, and macroalgae (location dependent) would make excellent nutritional contributions alongside animal-sourced food within LMICs within an agroecological framework. In contrast, highly processed plant-based meats, fungal biomass, and cultivated meat do not align well with agroecological principles for large-scale human consumption within LMICs. Furthermore, the production facilities to make these foods require robust capital investment and there may be issues related to who owns the intellectual property of these technologies. The NOVA classification system categorizes food based on the degree of processing. Our assessment suggests that foods with lower NOVA classification of unprocessed and minimally processed best fit the agroecological principles related to nutrition, agroecosystem, and societal demands for sustainable food systems.

Regional assessment of the historical trends of mercury in sediment cores from Wider Caribbean coastal environments.

Spatial and temporal variations of mercury (Hg) concentrations, enrichment, and potential ecological risks were studied in a suite of lead-210 (210Pb) dated sediment cores from 13 Wider Caribbean Region coastal environments. Broad variability of Hg concentrations (19-18761 ng g-1) was observed, encompassing even background levels (38-100 ng g-1). Most Hg concentration profiles exhibited a characteristic upward trend, reaching their peak values in the past two decades. Most of the sediment sections, showing from moderately to very severe Hg enrichment, were found in cores from Havana Bay and Sagua River Estuary (Cuba), Port-au-Prince Bay (Haiti), and Cartagena Bay (Colombia). These were also the most seriously contaminated sites, which can be considered regional Hg 'hotspots'. Both Havana Bay and Port-au-Prince Bay reportedly receive waste from large cities with populations exceeding 2 million inhabitants, and watersheds affected by high erosion rates. The records from the Sagua River Estuary and Cartagena Bay reflected historical Hg contamination associated with chloralkali plants, and these sites are of very high ecological risk. These results constitute a major contribution to the scarce regional data on contaminants in the Wider Caribbean Region and provide reference information to support the evaluation of the effectiveness of the Minamata Convention.

Age-associated Senescent - T Cell Signaling Promotes Type 3 Immunity that Inhibits the Biomaterial Regenerative Response.

Aging is associated with immunological changes that compromise response to infections and vaccines, exacerbate inflammatory diseases and can potentially mitigate tissue repair. Even so, age-related changes to the immune response to tissue damage and regenerative medicine therapies remain unknown. Here, it is characterized how aging induces changes in immunological signatures that inhibit tissue repair and therapeutic response to a clinical regenerative biological scaffold derived from extracellular matrix. Signatures of inflammation and interleukin (IL)-17 signaling increased with injury and treatment both locally and regionally in aged animals, and computational analysis uncovered age-associated senescent-T cell communication that promotes type 3 immunity in T cells. Local inhibition of type 3 immune activation using IL17-neutralizing antibodies improves healing and restores therapeutic response to the regenerative biomaterial, promoting muscle repair in older animals. These results provide insights into tissue immune dysregulation that occurs with aging that can be targeted to rejuvenate repair.

Transfer learning in a biomaterial fibrosis model identifies in vivo senescence heterogeneity and contributions to vascularization and matrix production across species and diverse pathologies.

Cellular senescence is a state of permanent growth arrest that plays an important role in wound healing, tissue fibrosis, and tumor suppression. Despite senescent cells' (SnCs) pathological role and therapeutic interest, their phenotype in vivo remains poorly defined. Here, we developed an in vivo-derived senescence signature (SenSig) using a foreign body response-driven fibrosis model in a p16-CreERT2;Ai14 reporter mouse. We identified pericytes and "cartilage-like" fibroblasts as senescent and defined cell type-specific senescence-associated secretory phenotypes (SASPs). Transfer learning and senescence scoring identified these two SnC populations along with endothelial and epithelial SnCs in new and publicly available murine and human data single-cell RNA sequencing (scRNAseq) datasets from diverse pathologies. Signaling analysis uncovered crosstalk between SnCs and myeloid cells via an IL34-CSF1R-TGFßR signaling axis, contributing to tissue balance of vascularization and matrix production. Overall, our study provides a senescence signature and a computational approach that may be broadly applied to identify SnC transcriptional profiles and SASP factors in wound healing, aging, and other pathologies.

Autologous Protein Solution processing alters lymphoid and myeloid cell populations and modulates gene expression dependent on cell type.

Osteoarthritis (OA) is a degenerative disease associated with cartilage degradation, osteophyte formation, and fibrillation. Autologous Protein Solution (APS), a type of autologous anti-inflammatory orthobiologic, is used for pain management and treatment of OA. Various compositions of autologous PRP formulations are in clinical use for musculoskeletal pathologies, by nature of their minimal processing and source of bioactive molecules. Currently, there is no consensus on the optimal composition of the complex mixture. In this study, we focused on elucidating the immune cell subtypes and phenotypes in APS. We identified the immune cell types in APS from healthy donors and investigated phenotypic changes in the immune cells after APS processing. Based on flow cytometric analysis, we found that neutrophils and T cells are the most abundant immune cell types in APS, while monocytes experience the largest fold change in concentration compared to WBCs. Gene expression profiling revealed that APS processing results in differential gene expression changes dependent on immune cell type, with the most significantly differentially regulated genes occurring in the monocytes. Our results demonstrate that the mechanical processing of blood, whose main purpose is enrichment and separation, can alter its protein and cellular composition, as well as cellular phenotypes in the final product.

Image-based cell subpopulation identification through automated cell tracking, principal component analysis, and partitioning around medoids clustering.

In vitro cell culture model systems often employ monocultures, despite the fact that cells generally exist in a diverse, heterogeneous microenvironment in vivo. In response, heterogeneous cultures are increasingly being used to study how cell phenotypes interact. However, the ability to accurately identify and characterize distinct phenotypic subpopulations within heterogeneous systems remains a major challenge. Here, we present the use of a computational, image analysis-based approach-comprising automated contour-based cell tracking for feature identification, principal component analysis for feature reduction, and partitioning around medoids for subpopulation characterization-to non-destructively and non-invasively identify functionally distinct cell phenotypic subpopulations from live-cell microscopy image data. Using a heterogeneous model system of endothelial and smooth muscle cells, we demonstrate that this approach can be applied to both mono and co-culture nuclear morphometric and motility data to discern cell phenotypic subpopulations. Morphometric clustering identified minimal difference in mono- versus co-culture, while motility clustering revealed that a portion of endothelial cells and smooth muscle cells adopt increased motility rates in co-culture that are not observed in monoculture. We anticipate that this approach using non-destructive and non-invasive imaging can be applied broadly to heterogeneous cell culture model systems to advance understanding of how heterogeneity alters cell phenotype. This work presents a computational, image-analysis-based approach-comprising automated contour-based cell tracking for feature identification, principle component analysis for feature reduction, and partitioning around medoids for subpopulation characterization-to non-destructively and non-invasively identify functionally distinct cell phenotypic subpopulations from live-cell microscopy image data.

Biomaterials direct functional B cell response in a material-specific manner.

B cells are an adaptive immune target of biomaterials development in vaccine research but, despite their role in wound healing, have not been extensively studied in regenerative medicine. To probe the role of B cells in biomaterial scaffold response, we evaluated the B cell response to biomaterial materials implanted in a muscle wound using a biological extracellular matrix (ECM), as a reference for a naturally derived material, and synthetic polyester polycaprolactone (PCL), as a reference for a synthetic material. In the local muscle tissue, small numbers of B cells are present in response to tissue injury and biomaterial implantation. The ECM materials induced mature B cells in lymph nodes and antigen presentation in the spleen. The synthetic PCL implants resulted in prolonged B cell presence in the wound and induced an antigen-presenting phenotype. In summary, the adaptive B cell immune response to biomaterial induces local, regional, and systemic immunological changes.

IL-17 and immunologically induced senescence regulate response to injury in osteoarthritis.

Senescent cells (SnCs) are implicated in the pathogenesis of age-related diseases including osteoarthritis (OA), in part via expression of a senescence-associated secretory phenotype (SASP) that includes immunologically relevant factors and cytokines. In a model of posttraumatic OA (PTOA), anterior cruciate ligament transection (ACLT) induced a type 17 immune response in the articular compartment and draining inguinal lymph nodes (LNs) that paralleled expression of the senescence marker p16INK4a (Cdkn2a) and p21 (Cdkn1a). Innate lymphoid cells, γδ+ T cells, and CD4+ T cells contributed to IL-17 expression. Intra-articular injection of IL-17-neutralizing antibody reduced joint degeneration and decreased expression of the senescence marker Cdkn1a. Local and systemic senolysis was required to attenuate tissue damage in aged animals and was associated with decreased IL-17 and increased IL-4 expression in the articular joint and draining LNs. In vitro, we found that Th17 cells induced senescence in fibroblasts and that SnCs skewed naive T cells toward Th17 or Th1, depending on the presence of TGF-ß. The SASP profile of the inflammation-induced SnCs included altered Wnt signaling, tissue remodeling, and cell-cycle pathways not previously implicated in senescence. These findings provide molecular targets and mechanisms for senescence induction and therapeutic strategies to support tissue healing in an aged environment.

Nonsteroidal Anti-Inflammatory Drug-Induced Leaky Gut Modeled Using Polarized Monolayers of Primary Human Intestinal Epithelial Cells.

The intestinal epithelium provides a critical barrier that separates the gut microbiota from host tissues. Nonsteroidal anti-inflammatory drugs (NSAIDs) are efficacious analgesics and antipyretics and are among the most frequently used drugs worldwide. In addition to gastric damage, NSAIDs are toxic to the intestinal epithelium, causing erosions, perforations, and longitudinal ulcers in the gut. Here, we use a unique in vitro human primary small intestinal cell monolayer system to pinpoint the intestinal consequences of NSAID treatment. We found that physiologically relevant doses of the NSAID diclofenac (DCF) are cytotoxic because they uncouple mitochondrial oxidative phosphorylation and generate reactive oxygen species. We also find that DCF induces intestinal barrier permeability, facilitating the translocation of compounds from the luminal to the basolateral side of the intestinal epithelium. The results we outline here establish the utility of this novel platform, representative of the human small intestinal epithelium, to understand NSAID toxicity, which can be applied to study multiple aspects of gut barrier function including defense against infectious pathogens and host-microbiota interactions.

Cambios en la actividad eléctrica ventricular durante el ejercicio isométrico en adultos jóvenes normorreactivos e hiperreactivos / Changes in ventricular electrical activity during isometric exercise in normoreactive and hyperreactive young adults

RESUMEN Introducción: Los individuos con hiperreación cardiovascular poseen un riesgo cinco veces superior de padecer hipertensión. En el contexto cubano no están descritos los cambios en la actividad eléctrica ventricular del electrocardiograma, durante la prueba isométrica del peso sostenido, y no se conoce si estos pueden estar influenciados por el grado de reactividad cardiovascular. Objetivo: Describir los parámetros de la actividad eléctrica ventricular en condiciones basales y durante el ejercicio isométrico, en adultos jóvenes de ambos sexos con diferente grado de reactividad cardiovascular. Métodos: La muestra estuvo constituida por 130 individuos de ambos sexos, y se dividió en dos grupos: Normorreactivos e hiperreactivos. A todos se les realizó un electrocardiograma digital en derivación DII; se utilizó el programa LabChart 8 en un polígrafo ADInstruments. Se estudiaron las siguientes variables: Complejo QRS, intervalo QT corregido (QTc), intervalo JT, intervalo Tpeak-Tend, amplitud del segmento ST y de la onda T en reposo, en el ejercicio isométrico y durante la recuperación. Resultados: Entre las mujeres normorreactivas e hiperreactivas se encontraron diferencias significativas en la amplitud de la onda T, tanto basales, durante el ejercicio isométrico, como en la recuperación. Entre los hombres de ambos grupos solo se encontraron diferencias significativas en el intervalo JT, durante el ejercicio. Conclusiones: Los cambios producidos en la regulación autonómica de la función cardíaca durante el ejercicio isométrico y la recuperación, se reflejaron en la actividad eléctrica ventricular en los individuos normorreactivos e hiperreactivos de ambos sexos, principalmente en el intervalo JT y la altura de la onda T.

ABSTRACT Introduction: individuals with cardiovascular hyperreaction have a five times higher risk of suffering from hypertension. In the Cuban context, the changes in the ventricular electrical activity of the electrocardiogram during the sustained weight isometric test have not been described, and it is not known whether these may be influenced by the degree of cardiovascular reactivity. Objective: to describe the parameters of ventricular electrical activity in basal conditions and during isometric exercise, in young adults of both genders with different degrees of cardiovascular reactivity. Methods: the sample consisted of 130 individuals of both genders, and was divided into two groups: normoreactive and hyperreactive. All of them underwent a digital electrocardiogram in DII lead; LabChart 8 software on an ADInstruments polygraph was used. The following variables were studied: QRS complex, corrected QT interval (QTc), JT interval, Tpeak-Tend interval, ST segment and T wave amplitude at rest, in isometric exercise and during recovery. Results: significant differences between normoreactive and hyperreactive women were found in the amplitude of the T wave, both at baseline, during isometric exercise, and in recovery. Significant differences were only found between men in both groups in the JT interval, during exercise. Conclusions: the changes produced in the autonomic regulation of cardiac function during isometric exercise and recovery were reflected in the ventricular electrical activity in normoreactive and hyperreactive individuals of both genders, mainly in the JT interval and the height of the T wave.

Chemical composition and antibacterial activity of the essential oil of Ruilopezia bracteosa.

The essential oil from the leaves ofRuilopezia bracteosa was obtained by hydrodistillation, and analyzed by GC-MS. Eighteen components, which made up 99.6% of the oil were identified, the most abundant being ß-myrcene (34.2%), α-pinene (24.3%), 7-epi-α-selinene (9.1%), ß-pinene (8.5%) and 6,9-guaiadiene (4.4%). Antibacterial activity was tested against Gram-positive and Gram-negative bacteria using broth microdilution and disk agar diffusion methods. MIC values found presented significant differences between both methods, which may be due to diffusion factors.

Balance autonómico basal y durante el ejercicio isométrico en jóvenes con diferente reactividad cardiovascular / Basal autonomic balance and during the isometric exercise in young people with different cardiovascular reactivity

RESUMEN Introducción: El sistema nervioso autónomo desempeña un papel importante en los reajustes cardiovasculares al ejercicio. En la hiperreactividad cardiovascular existe una mayor sensibilidad del sistema simpático ante diferentes estímulos estresantes. Objetivo: Determinar las características del control autonómico cardíaco en adultos jóvenes con diferentes grados de reactividad cardiovascular en condiciones basales y durante el ejercicio isométrico. Método: La muestra estuvo constituida por 97 individuos de ambos sexos, y se dividió en tres grupos: normorreactivos, hiperreactivos y con respuesta hipertensiva, de acuerdo a la respuesta presora a la prueba del peso sostenido. A todos los individuos se les realizó un estudio de variabilidad de la frecuencia cardíaca en reposo y durante la prueba isométrica. Se estudiaron las variables en el dominio de la frecuencia: baja, alta, relación baja/alta en reposo, y los parámetros del diagrama de Poincaré en reposo y durante el ejercicio (valores de desviación estándar 1 [SD1], 2 [SD2], y la razón entre ambos). Resultados: En estado basal los individuos hiperreactivos y con respuesta hipertensiva presentaron un predominio simpático sobre la función cardíaca y una menor variabilidad de la frecuencia cardíaca. Durante el ejercicio isométrico disminuyeron los valores de los ejes SD1 y SD2 en todos los grupos y la razón SD1/SD2 decreció en individuos normorreactivos y con respuesta hipertensiva; pero apenas se modificó en los hiperreactivos. Conclusiones: En los individuos con hiperreactividad cardiovascular ya está presente un desbalance autonómico en estado basal y existe una reducción de la modulación autonómica vagal durante el ejercicio, que puede favorecer el desarrollo de la hipertensión arterial.

ABSTRACT Introduction: The autonomic nervous system plays an important role in cardiovascular readjustments to exercise. In cardiovascular hyperreactivity there is a greater sensitivity of the sympathetic system to different stressors. Objective: To determine the characteristics of cardiac autonomic control in young adults with different degrees of cardiovascular reactivity under basal conditions and during isometric exercise. Method: The sample consisted of 97 individuals of both sexes, and was divided into three groups: normoreactive, hyperreactive and with hypertensive response, according to the pressor response to weight-bearing tests. The individuals underwent a complete study of heart rate variability at rest and during isometric test. The frequency domain for the variables was: low, high, low/high resting ratio, and the parameters of Poincaré plots at rest and during exercise (values of standard deviation 1 [SD1], 2 [SD2], and the reason between them). Results: Under basal conditions, hyperreactive individuals with a hypertensive response had a sympathetic predominance over cardiac function and lower heart rate variability. During the isometric exercise SD1 and SD2 axes values decreased in all groups and SD1/SD2 ratio decreased in normoreactive individuals with hypertensive response; but it was hardly modified in those hyper-reactive. Conclusions: Individuals with cardiovascular hyperreactivity have a prior autonomic imbalance under basal conditions and a reduction of autonomic vagal modulation during exercise that may favor the development of arterial hypertension.

Introducción de la asignatura Sangre y Sistema Inmune: satisfacción y desempeño de los estudiantes / Introduction to the Blood and Immune System subject: satisfaction and student´s performance

RESUMEN Fundamento: en el curso 2017-2018 se introdujo la asignatura Sangre y Sistema Inmune en el tercer semestre de la carrera de Medicina, según el nuevo plan de estudio. Objetivos: identificar el grado de satisfacción y desempeño de los estudiantes en la asignatura Sangre y Sistema Inmune de recién incorporación en el Plan de Estudios D. Método: se realizó un estudio descriptivo en la Universidad de Ciencias Médicas de Villa Clara en el curso académico 2017-2018. Se utilizaron métodos teóricos: análisis-síntesis e inducción-deducción, empíricos: la encuesta en forma de cuestionario en dos momentos concretos del semestre (cuarta y decimoquinta semanas), y matemático-estadísticos para el procesamiento de los datos. Resultados: en sentido general la introducción de la asignatura Sangre y Sistema Inmune en el currículo tuvo un nivel adecuado de aceptación por los alumnos y este evolucionó de forma positiva en la medida en que transcurrió el curso. En los casos de insatisfacción, la principal causa estuvo vinculada a la dificultad de los temas impartidos. Existe preferencia por las clases talleres y prácticas de laboratorio, y el trabajo de curso como evaluación final, y no con un examen teórico. Conclusiones: el nivel de satisfacción expresado por los alumnos con la asignatura fue adecuado, no así el desempeño ya que la mayoría reconocieron no poseer los conocimientos básicos sobre su contenido, aspectos que se tuvieron en cuenta en su posterior impartición.

ABSTRACT Background: in the 2017-2018 academic year, the Blood and Immune System subject was introduced in the third semester of the Medicine degree, according to the new study plan. Objectives: to identify the degree of satisfaction and performance of students in the Blood and Immune System subject of recent incorporation in the Study Plan D. Methods: a descriptive study was carried out at Villa Clara University of Medical Sciences in the academic year 2017-2018. Theoretical methods were used: analysis-synthesis and induction-deduction, empirical ones: the survey in the form of a questionnaire in two specific moments of the semester (fourth and fifteenth weeks), and mathematical-statistics for data processing. Results: in general, the introduction of the Blood and Immune System subject in the curriculum had an adequate level of acceptance by the students and this evolved in a positive way to the extent that the course lasted. In cases of dissatisfaction, the main cause was linked to the difficulty of the subjects taught. There is a preference for workshops and laboratory practices, and a course project work as a final evaluation, and not with a theoretical exam. Conclusions: the level of satisfaction expressed by the students with the subject was adequate, not so the performance since most acknowledged not having the basic knowledge about its content, aspects that were taken into account in its subsequent teaching.

Chemical composition and antibacterial activity of the essential oil of Espeletia nana.

The essential oil of the leaves of Espeletia nana Cuatrec., obtained by hydrodistillation, was analyzed by GC-MS, which allowed the identification of 24 components, which made up 99.9% of the oil. The most abundant compounds were a-pinene (38.1%), beta-pinene (17.2%), myrcene (15.0%), spathulenol (4.2%), bicyclogermacrene (4.0%), a-zingiberene (4.0%), and gamma-himachalene (3.7%). Antibacterial activity was tested against Gram-positive and Gram-negative bacteria using the agar disk diffusion method. Activity was observed only against Gram-positive bacteria. MIC values were determined for Staphylococcus aureus ATCC 25923 (200 microg/mL) and Enterococcusfaecalis ATCC 29212 (600 microg/mL).