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Objetivo: Evaluar, a lo largo de un seguimiento de 79,2 meses, el comportamiento de la densidad mineral ósea (DMO) determinada mediante Densitometría Axial Computarizada (DXA), la densidad mineral ósea volumétrica (DMOvol) y su relación con los datos antropométricos, junto con los parámetros relativos al metabolismo óseo (calcio, fósforo, fosfatasa alcalina, parathormona (PTH) y vitamina D (25-OH-D3)) en una población infantil con Diabetes Mellitus Tipo 1 (DM1) sin complicaciones microvasculares y un grupo control de referencia de similares características. Material y métodos: Inicialmente, se realizó un estudio transversal en 40 niños diabéticos (edad media 9,4±2,8 años) y 108 controles (9,3±1,5 años) para valorar las posibles diferencias entre ambas poblaciones. 26 pacientes del grupo diabético inicial, fueron reevaluados tras 79,2 meses de seguimiento. Resultados: Se observó que, al inicio, la masa ósea fue similar en los diabéticos y controles. Después del seguimiento, la DMO de los niños diabéticos era muy inferior a la esperada en población infantil no diabética. El peso, la altura y el Índice de Masa Corporal (IMC) siguieron el mismo patrón que la DMO. Los valores de calcio, fósforo, fosfatasa alcalina, PTH y vitamina D, aunque en rango de normalidad, fueron más bajos que en los controles. La fosfatasa alcalina no se incrementó en el periodo puberal. Conclusiones: El presente estudio demuestra que los niños y adolescentes con un diagnóstico reciente de DM1 tienen una DMO normal. Sin embargo, con el paso del tiempo, y sobre todo durante la adolescencia, muestran una menor ganancia de masa ósea y alteraciones en los parámetros de recambio óseo.

Assessing biomass is critical for accounting bioenergy potentials and monitoring forest ecosystem responses to global change and disturbances. Remote sensing, especially Light Detection and Ranging (LiDAR) data combined with field data, is being increasingly used for forest inventory purposes. We evaluated the feasibility of the combined use of freely available data, both remote sensing (LiDAR data provided by the Spanish National Plan for Aerial Ortophotography - PNOA - and Landsat vegetation spectral indices) and field data (from the National Forest Inventory) to estimate stand dendrometric and aboveground biomass variables of the most productive tree species in a pilot area in Galicia (northwestern Spain). The results suggest that the models can accurately predict dendrometric and biomass variables at plot level with an R2 ranging from 0.49 to 0.65 for basal area, from 0.65 to 0.95 for dominant height, from 0.48 to 0.68 for crown biomass and from 0.55 to 0.82 for stem biomass. Our results support the use of this approach to reduce the cost of forest inventories and provide a useful tool for stakeholders to map forest stand variables and biomass stocks.

Juan A Castelán-Vega, Anastasia Magaña-Hernández, Alicia Jiménez-Alberto, Rosa María Ribas-AparicioDepartamento de Microbiología, Escuela Nacional de Ciencias Biológicas del Instituto Politécnico Nacional, Mexico City, MexicoAbstract: The last influenza A pandemic provided an excellent opportunity to study the adaptation of the influenza A(H1N1)pdm09 virus to the human host. Particularly, due to the availability of sequences taken from isolates since the beginning of the pandemic until date, we could monitor amino acid changes that occurred in the hemagglutinin (HA) as the virus spread worldwide and became the dominant H1N1 strain. HA is crucial to viral infection because it binds to sialidated cell-receptors and mediates fusion of cell and viral membranes; because antibodies that bind to HA may block virus entry to the cell, this protein is subjected to high selective pressure. Multiple alignment analysis of sequences of the HA from isolates taken since 2009 to date allowed us to find amino acid changes that were positively selected as the pandemic progressed. We found nine changes that became prevalent: HA1 subunits D104N, K166Q, S188T, S206T, A259T, and K285E; and HA2 subunits E47K, S124N, and E172K. Most of these changes were located in areas involved in inter- and intrachain interactions, while only two (K166Q and S188T) were located in known antigenic sites. We conclude that selective pressure on HA was aimed to improve its functionality and hence virus fitness, rather than at avoidance of immune recognition.Keywords: influenza A, hemagglutinin evolution, virus fitness

Mario A Rodríguez-Pérez1, Juan Antonio Pérez-Vega2, José Francisco Cen-Aguilar3, Rossanna Rodríguez-Canul21Centro de Biotecnología Genómica, Instituto Politécnico Nacional, Ciudad Reynosa, Tamaulipas, 2Centro de Investigación y de Estudios Avanzados del IPN Unidad Mérida, Mérida Yucatán, 3Oficina de Investigación y validación, Centro de Bachillerato Tecnológico y Agropecuario (CBTA) 13, Xmatkuil, Mérida, Yucatán, MexicoPurpose: To determine the prevalence of gastrointestinal parasites and evaluate the effect of a single dose of treatment with albendazole in a sentinel group from a rural community in southern Mexico.Methods: Stool samples were collected from 1456 individuals aged ≥1 year during consecutive days, and examined for helminth infection using the modified Stoll dilution method. Additionally, 104 individuals were treated with a single dose of albendazole and evaluated over 21 weeks to assess reinfection. Questionnaires were administered to obtain individual and household-level data pertaining to behavior, demography, and socioeconomic status. Risk factors for reinfection after albendazole administration were determined using multiple logistic regression analyses.Results: The prevalence of Ascaris lumbricoides was 73.9% (95% confidence interval [CI] = 71.56%–76.14%). Albendazole was 100% effective, but eggs began to be detected by 9–12 weeks posttreatment, increasing to 100% after 21 weeks. Logistic regression analysis revealed that all individuals from this study had a probability of reinfection of 1.65× each week after treatment. The prevalence of Trichuris trichiura was 57.2% (95% CI = 54.62%–59.77%) and chemotherapy was 34.7% effective. The prevalence for other minor gastrointestinal parasites ranged from 0.2% to 29.7%.Conclusion: This was a comprehensive study on gastrointestinal parasites in a rural community from southern Mexico and, to the best of the authors’ knowledge, is the first time that the effect of albendazole has been evaluated for a period of over 21 weeks following its administration. Risk factors associated with parasite transmission were linked to poverty and lack of hygiene, such as, defecating in open places, living customs (drinking piped water and/or from a well), and absence of knowledge about transmission life cycle of the parasites. Studies of this kind should be linked to health education and improvement of access to clean water and adequate sanitation to consolidate morbidity control and enhance sustainability.Keywords: Ascaris lumbricoides, Trichuris trichiura, polyparasitism, risk factors, albendazole