Resumen: Antecedentes: El conocimiento de los atributos estructurales y el hábitat de las especies son fundamentales para evaluar su estado de conservación y proponer acciones para su conservación y manejo. Preguntas: ¿Cuáles son los atributos estructurales de la poblacional de J. jaliscana, las características de su hábitat y los factores ambientales que podrían estar influyendo en su distribución y abundancia? Sitio y periodo de estudio: El muestreo de campo se realizó en poblaciones de J. jaliscana en el ejido El Cuale, municipio de Talpa de Allende, Jalisco, México, en julio de 2019. Métodos: En parcelas de 500 m2 se determinaron los atributos estructurales de la poblacional de J. jaliscana y a través de un RDA se evaluó cuales factores ambientales podrían influir en su distribución y abundancia. Se describió la composición y estructura de toda la comunidad vegetal. Resultados: Juniperus jaliscana registró 385 ind. ha-1 y un área basal de 8.98 m2 ha-1. Las variables con mayor influencia sobre su abundancia y distribución fueron la incidencia de incendios y el pastoreo. Se registraron 119 especies, 94 géneros y 52 familias. Psidium salutare se registró por primera vez para el estado de Jalisco y se describió como especie nueva para la ciencia a Prionosciadium tamayoi. Conclusiones: Juniperus jaliscana concentró su población en categorías diamétricas pequeñas. Los factores ambientales con mayor influencia sobre su distribución y abundancia fueron los incendios, pastoreo y condiciones de ambientes secos. Juniperus jaliscana comparte hábitat con especies endémicas al occidente de México.

Abstract: Background: Knowledge of structural attributes and the habitat of the species is essential to assess their conservation status and propose actions for their conservation and management. Questions: What are the structural attributes of the population of J. jaliscana, the characteristics of its habitat, and the environmental factors that could be influencing its distribution and abundance? Study site and dates: The field sampling was carried out in populations of J. jaliscana in ejido El Cuale, municipality of Talpa de Allende, Jalisco, México, in July 2019. Methods: In plots of 500 m2, the structural attributes of the population of J. jaliscana were determined and through an RDA, the environmental factors that could be influencing its distribution and abundance were investigated. The composition and structure of the entire community was described. Results: Juniperus jaliscana registered 385 ind. ha-1 and a basal area of 8.98 m2 ha-1. The variables with the greatest influence on the abundance and distribution of J. jaliscana were the incidence of fires and grazing. 119 species, 94 genera and 52 families were recorded. Psidium salutare was found for the first time for the state of Jalisco and Prionosciadium tamayoi was described as a new species for science. Conclusions: Juniperus jaliscana concentrated its population in small diameter categories. The environmental factors with the greatest influence on their distribution and abundance were fires, grazing and dry environment conditions. The habitat of J. jaliscana was shared with species endemic to western Mexico.

Abstract Nowadays, cardiac transplant is considered the most efficient treatment to better the prognosis in patients with last stage cardiac insufficiency that is impossible to obtain through regular medical and/or surgical treatments. We report the case of the first cardiac transplant performed at the General Hospital of Mexico "Dr. Eduardo Liceaga," we describe the patient's and donor's characteristics, pre- and post-surgical management, immunosuppressive therapy, cardiac rehabilitation, and patient follow-up. As well as the multidisciplinary approach necessary to achieve a successful result.

SUMMARY Forest inventory is the primary method for collecting and recording information regarding the volumetric quantification and yield of trees. However, this is difficult when the individual has been cut and only the stump remains, in which case inventory is achieved through regression techniques. The objective of this work was to adjust allometric equations for the estimation of normal diameter (dn), total height (at) and volume (v) using the stump diameter (dt) for Abies religiosa in different regions of Mexico. A total of 2,599 data points from 20 forest management units were used to analyze the variables and their respective predictions through eight allometric equations, which were evaluated with different statistical criteria. The adjusted coefficient of determination (R2 adj) explained 91 % of the normal diameter, together with the root mean square error (RMSE) of less than 4.75 cm with respect to the allometric equation (3). Another of the best options to estimate the total height is the Schumacher exponential (4) and the allometric (6) with values of R2 adj of approximately 50 %, accompanied by RMSE less than 5.03 m. However, for the volume of the forest, Schumacher's equation was considered pertinent since it has a RMSE ranging from 0.00001 to 0.0026 m3 with R2 adj that explains more than 74 % of the variation of the data observed in each UMAFOR. These regressions may be useful for the restoration of trees after an unplanned or unexpected felling event, as the results are statistically reliable.

RESUMEN Los inventarios forestales son los métodos de recolección y registro de información para la cuantificación volumétrica y rendimiento de los árboles; sin embargo, esto se dificulta cuando el individuo ha sido cortado y solo permanece el tocón, y esto se logra mediante técnicas de regresión. El objetivo de este trabajo fue ajustar ecuaciones alométricas para la estimación del diámetro normal (dn), altura total (at) y volumen (v) fustal a partir del diámetro del tocón (dt) para Abies religiosa en diferentes regiones de México. Se utilizaron 2.599 datos provenientes de 20 forest management units para analizar las variables con sus respectivas predicciones a través de ocho ecuaciones alométricas; mismas que fueron evaluadas con diferentes criterios estadísticos. El coeficiente de determinación ajustado (R2 adj) explicó el 91 % sobre el diámetro normal, en conjunto con la raíz del error medio cuadrático (REMC) menores a 4,75 cm respecto a la ecuación alométrica (3), también las mejores opciones para estimar la altura total está la de Schumacher exponencial (4) y la alométrica (6) con valores de R2 adj aproximado de 50 %, acompañado de REMC menores a 5,03 m; mientras que, para el volumen fustal, se consideró pertinente la ecuación de Schumacher al tener una REMC que oscilan entre 0,00001 a 0,0026 m3 con R2 adj que explica más del 74 % la variación de los datos observados en cada UMAFOR. Estas regresiones podrán ser de utilidad para la reconstrucción de los árboles después de un evento de derribo no previsto o acontecido, al tener resultados estadísticamente confiable.

ABSTRACT The wild pepper (Capsicum annuum L. var. glabriusculum (Dunal) Heiser & Pickersgill) is a valuable genetic resource for agriculture and food. Around the world salinity is a significant environmental stress that limit and affect agriculture productivity. This work estimates the variation in salinity tolerance in six populations of wild pepper populations of the Northwest of Mexico at three salinity levels (without NaCl, 25 and 50 mM NaCl). The measured traits were height, stem development, foliar area, relative content of chlorophyll, dry weight of plant, root, stem, and leaves. Salinity tolerance was estimated with a stress tolerance index (STI) obtained by comparing values of traits between control treatment (without NaCl) and salinity treatments. Data were subjected to univariate and multivariate variance analysis of principal components. All measured traits were negatively and significantly affected by salinity. Univariate variance analysis and of principal components clearly differentiated the studied populations. At 50 mM NaCl, height, stem diameter, foliar area, stem and leaves dry weight correlated positively with electrical conductivity, and foliar area, relative content of chlorophyll, stem and leaves dry weight correlated with soil Na at the site of origin of the populations. Presa Oviachic showed a higher salinity tolerance in both NaCl treatments (1.17 and 0.99), followed by two more populations (Lo de Vega and Yecorato), each with each salinity treatment. Presa Oviachic presented the highest average STI in both treatments, 37.6% and 40.4% higher than Cósala and Mazocahui respectively. Root dry weight (0.427), stem diameter (0.419), leaf area (0.412), stem dry weight (0.407) and plant dry weight (0.345) were the most important traits in that order and Presa Oviachic was significantly superior to the rest of populations in STI at 50 mM NaCl. Plants of these populations could be a source of salinity resistance. The variation pattern observed in these traits suggests adaptation to the local edaphic conditions.

Resumen Objetivo: Describir medidas de presión arterial sistólica (PAS), diastólica (PAD) y media (PAM) en recién nacidos sanos de término y pretérmino tardío para establecer parámetros de normalidad. Método: Estudio transversal realizado en el cunero fisiológico del Hospital Español, Ciudad de México. Se incluyeron 551 pacientes recién nacidos sanos. Las tomas de PA fueron realizadas dentro de las primeras 48 horas de vida con método oscilométrico. Posterior a la evaluación de normalidad, se realizó un análisis descriptivo de la población y cálculo de percentiles (25, 50 y 75) específicos para cada semana de gestación. Todos los análisis fueron realizados en STATA v14.2. Resultados: Los recién nacidos de sexo masculino tuvieron un valor medio de PAS de 64.6 mmHg en la semana 35 de gestación, este valor aumentó a 69.8 mmHg en la semana 40. El valor de la PAD fue de 42.6 mmHg en la semana 35 de gestación, disminuyendo a 40.8 mmHg para la semana 40. Los valores medios de PAS en los recién nacidos de sexo femenino fueron de 65.5 mmHg en la semana 35, teniendo un incremento a 73.5 mmHg en la semana 40. El valor de la PAD en la semana 35 de gestación fue 38 mmHg, incrementando a 41.3 mmHg en la semana 40. Conclusiones: Los valores de PA en recién nacidos sanos se modifican con la edad gestacional y el sexo. Estos resultados pueden servir como referencia para otros médicos ubicados en países o ciudades con alturas similares a la Ciudad de México.

Abstract Objective: Describe the measurements of systolic, diastolic and mean blood pressure in healthy term and late preterm newborns to establish normal values. Methods: Cross-sectional study carried out in the nursery of the Hospital Español, located in Mexico City. A sample of 551 healthy newborns were included in the study. Blood pressure (BP) measurements were taken within the first 48 hours of life with the oscillometric method. After the evaluation of normality, a descriptive analysis of the population and calculation of percentiles (25, 50 and 75) specific for each week of gestation was performed. All analyzes were performed in STATA v14.2. Results: Male newborns had a mean SBP value of 64.6 mmHg at week 35 of gestation, this value increased to 69.8 mmHg at week 40; the systolic blood pressure (SBP) value was 42.6 mmHg at week 35 of gestation, which decreased to 40.8 mmHg at week 40. The mean SBP values in female newborns were 65.5 mmHg at week 35, increasing to 73.5 mmHg at week 40; the diastolic blood pressure (DBP) value at week 35 of gestation was 38 mmHg, increasing to 41.3 mmHg at week 40. Conclusions: The BP values in healthy newborns are modified by the gestational age and sex of the patients. These results can serve as a reference for other physicians located in countries or cities with a similar altitude than the one in Mexico City.

Resumen Los sistemas agroforestales y la diversificación productiva son alternativas sostenibles que revierten los daños y riesgos de la agricultura convencional. Existen pocos estudios de sostenibilidad que permitan incorporarlos a proyectos destinados a aumentar la rentabilidad y mejorar el bienestar de los productores, restaurando los servicios ecosistémicos. El objetivo fue evaluar la sustentabilidad de dos sistemas agroforestales tradicionales, diversificados con cacao y vainilla, en los estados de Veracruz y Oaxaca. Se promovieron técnicas agroecológicas y estrategias de desarrollo empresarial con las familias de ambos productores. La investigación se llevó a cabo durante el periodo: febrero 2012 a julio 2020, las parcelas están ubicadas en los municipios de San Pedro Ixcatlán, Oaxaca y Papantla, Veracruz. Se utilizó la metodología del marco de evaluación de sistemas de gestión de recursos naturales. Los resultados mostraron que los estados iniciales tenían un manejo poco intensivo, bajo uso de insumos, alta diversificación y orientado a la agricultura de subsistencia. Tras la diversificación, manejo agroecológico y desarrollo empresarial, los estados de transición han mejorado en la mayoría de los indicadores de sostenibilidad. En particular la rentabilidad (índice beneficio-costo), que alcanzó 1.2 para San Pedro y 2.6 para Papantla cuando se da valor agregado a la vainilla y el cacao. Es relevante la participación de las mujeres en actividades emergentes derivadas de la diversificación y el interés de los jóvenes por continuar con actividades de transformación de materias primas y la comercialización de productos de valor agregado.

Abstract Agroforestry systems and productive diversification are sustainable alternatives that reverse the damages and risks of conventional agriculture. There are few sustainability studies that allow them to be incorporated into projects aimed at increasing profitability and improving the welfare of producers, restoring ecosystem services. The objective was to assess the sustainability of two traditional agroforestry systems, diversified with cacao and vanilla, in the states of Veracruz and Oaxaca. Agroecological techniques and business development strategies were promoted with the families of both producers. The research was carried out during the period: February 2012 to July 2020, the plots are located in the municipalities of San Pedro Ixcatlán, Oaxaca and Papantla, Veracruz. The methodology of the framework of assessment of natural resource management systems was used. The results showed that the initial states had a low intensive management, low use of inputs, high diversification and oriented to subsistence agriculture. After diversification, agroecological management and business development, transition states have improved in most sustainability indicators. In particular, profitability (benefit-cost index), which reached 1.2 for San Pedro and 2.6 for Papantla when added value is given to vanilla and cacao. The participation of women in emerging activities derived from diversification and the interest of young people to continue with activities of transformation of raw materials and the commercialization of value-added products are relevant.

Abstract Background: Since the beginning of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, patients with chronic kidney disease vulnerable to suffering more severe COVID-19 disease and worse outcomes have been identified Objectives: Our study's aim was to determine the incidence, characteristics, and outcomes of SARS-CoV-2 infection in patients of hemodialysis (HD) units in Mexico and to describe the availability of confirmatory testing Methods: This study was multicentric study of 19 HD units, conducted between March 2020 and March 2021 Results: From a total of 5779 patients, 955 (16.5%) cases of suspicious COVID-19 were detected; a SARS-CoV-2 reverse transcription polymerase chain reaction test was done in only 50.6% of patients. Forty-five percentages were hospitalized and 6% required invasive mechanical ventilation (IMV). There was no significant difference in mortality between confirmed (131/483) and suspicious (124/472) cases (p = 0.74). The percentage of patients in need of hospitalization, IMV, and deceased was greater than in the rest of the study population Conclusions: The study revealed that 49.4% of the cases were not confirmed, a worrisome observation given that this is a highly vulnerable population (higher probability of contagion and worse outcomes), in which 100% of patients should have a confirmatory test

Abstract Background: A high incidence of acute kidney injury (AKI) has been reported in coronavirus disease 2019 (COVID-19) patients in critical care units and those undergoing invasive mechanical ventilation (IMV). The introduction of dexamethasone (DXM) as treatment for severe COVID-19 has improved mortality, but its effects in other organs remain under study. Objective: The objective of this study was to evaluate the association between DXM and AKI in COVID-19. Methods: In this prospective observational cohort study, we evaluated the incidence of AKI in critically ill COVID-19 patients undergoing mechanical ventilation, and the association of DXM treatment with the incidence, severity, and outcomes of AKI. The association between DXM treatment and AKI was evaluated by multivariable logistic regression. The association of the combination of DXM treatment and AKI on mortality was evaluated by Cox-regression analysis. Results: We included 552 patients. AKI was diagnosed in 311 (56%), of which 196 (63%) corresponded to severe (stage 2 or 3) AKI, and 46 (14.8%) received kidney replacement therapy. Two hundred and sixty-seven (48%) patients were treated with DXM. This treatment was associated to lower incidence of AKI (Odds Radio 0.34, 95% Confidence intervals [CI] 0.22-0.52, p < 0.001) after adjusting for age, body mass index, laboratory parameters, SOFA score, and vasopressor use. DXM treatment significantly reduced mortality in patients with severe AKI (HR 0.63, 95%CI 0.41-0.96, p = 0.032). Conclusions: The incidence of AKI is high in COVID-19 patients under IMV. DXM treatment is associated with a lower incidence of AKI and a lower mortality in the group with severe AKI.

ABSTRACT Aquaculture combines techniques for breeding and harvesting aquatic organisms used in shrimp production. It is important as a source of income and for generating foreign exchange in the regions where it is practiced. However, the timely detection of diseases continues to be a great challenge for aquaculture and fisheries production. In recent years, Enterocytozoon hepatopenaei (EHP) has emerged as a major pathogen of the Pacific white shrimp Penaeus vannamei in many Asian countries (Vietnam, China, Indonesia, Malaysia, Thailand, India, and Korea). In Latin America, only in Venezuela, and to date, there is no report of its presence in Mexico. It is transmitted directly from shrimp to shrimp by oral or fecal means, cannibalism, or exposure to contaminated water. Hepatopancreatic microsporidiosis (HPM) is mainly associated with stunted growth and severe infections that can cause a poor production cycle, mortality, and problems in larva-producing laboratories. This review aims to overview the main microsporidian parasites and diseases found in white shrimp, including the clinical signs, control and prevention measures for EHP infection, and the detection of HPM using different techniques. In order to offer timely detection tools, different techniques are available for the detection and study of microsporidia. Such as optical microscopy, transmission electron microscopy, and histology; however, for diagnostic purposes, molecular methods are preferred due to their sensitivity, specificity, and short-time analysis. Our review suggests that constant monitoring in shrimp hatcheries and farms is essential to avoid the entry or transference of infected organisms, affecting shrimp production and the ideal development of healthy shrimp.

Resumen La localidad Área Nueva, se ubica, en la porción NE de la Sierra de Guadalupe, en la ladera sur del domo La Cantera, el cual presenta un escarpe intensamente diaclasado y fracturado, de 450 m de longitud. En este estudio se realizó un inventario de 114 depósitos de caídas de rocas, en los que se obtuvo para los bloques mayores, su posición geográfica, altitud, pendiente, distancia del escarpe, volumen y adherencia del bloque sobre la superficie del terreno. Con esta información y el uso de sistemas de información geográfica, se elaboraron los mapas de pendientes, curvatura del terreno y geomorfológico. Para complementar el inventario de depósitos de caídas de rocas, se obtuvo la imagen de un drone de baja altitud, cuyo sobrevuelo fue a 80 m de altura y posteriormente se procesó la información. Además, se realizó un análisis estadístico, con la finalidad de determinar la distribución de los bloques y su posible relación con los factores que puedan influir en el tamaño del bloque y la distancia potencial de recorrido del mismo. El grado de la pendiente influye de manera significativa en el alcance potencial del recorrido de los bloques rocosos inestables, que pudieran desprenderse del escarpe. La distancia de recorrido de las rocas, es menor cuando las pendientes son mayores de 45°, correspondientes a la ubicación del escarpe y los bloques de menor volumen, son los que alcanzan distancias mayores; sin embargo por la cercanía de los asentamientos humanos a 120 m del escarpe y la intensidad de la deforestación, por la presión que ejercen los habitantes en la zona, incrementa la posibilidad de que los bloques que se desprendan del escarpe, incrementen su alcance potencial de recorrido y lleguen a impactar sobre las casas y las personas, ocasionando daños considerables. El aumento de la deforestación, ha dejado al descubierto bloques rocosos inestables, que aunado, a eventos detonantes de los desprendimientos de rocas, por las grandes avenidas durante lluvias torrenciales y la sismicidad, incrementa la susceptibilidad a caídas de rocas.

Abstract Among the natural events that have caused great human and economic damage in the world, rockslides occurring on unstable slopes, due to their geological and geomorphological characteristics, together with the triggering factors (earthquakes, torrential rains, anthropogenic processes) that accelerate their fall, stand out. Population growth and the economic position prevailing in many social nuclei, mostly in extreme poverty and in need of housing, is reflected in the occupation of hillside areas, without considering the dangers of rock falls. In areas susceptible to this process, studies have been carried out using various methodologies to determine its causes, the degree of impact on the population living there and the probability of preventing or mitigating it. Since the industrialization during the 1970s in part of the Basin of Mexico and adjacent to the Sierra de Guadalupe, migrants from different states arrived in search of employment, which increased the demand for urban land and, consequently, the territorial occupation of the hillsides of the sierra, where some leaders offered them land at low cost, without considering the risk to which they are exposed by landslides and falling blocks, mainly during the rainy season or when seismic events occur. The formation of the sierra derives from Pleistocene volcanic activity, which has given rise to several volcanoes, domes and spills that present fractures (diaclases) and faults of tectonic origin, with a predominant NW-SE and E-W direction. Prior to intense urbanization the area was used to exploit material banks, which was often done with the help of dynamite for the extraction of materials, which in some areas intensified the fracturing by blasting effects. During the earthquakes that occurred in September 2017, 2 large unstable blocks detached from the dome called "Cerro Gordo", located in the southern portion of the study area. The study area corresponds to the locality of Área Nueva, which is located in the NE portion of the Sierra de Guadalupe, on the southern slope of the La Cantera dome, and which presents an intensely diaclased and fractured escarpment, 450 m long and an average height of 30 m. In this study, an inventory of 114 rockfall deposits was carried out, in which the geographic position, altitude, slope, distance from the escarpment, volume and adherence of the block to the ground surface were obtained for the blocks. With this information and the use of geographic information systems, slope, terrain curvature and geomorphological maps were prepared. The vegetation index (NVDI) was obtained with Sentinel satellite information (analysis of satellite images from 2016 to 2021). In addition to the inventory of rockfall deposits, images of the study area were obtained from a low-altitude drone, whose overflight was at an altitude of 80 m, and the information was subsequently processed to obtain the orthophoto and digital elevation model (DEM). With this information, a statistical analysis was carried out to determine the distribution of the blocks, their size and their potential travel distance. From the results obtained, it was observed that the slope grade significantly influences the potential travel distance of the unstable rock blocks. The distance of travel of the rocks is less when the slopes are greater than 45°, corresponding to the location of the escarpment, and the blocks of smaller volume are those that reach greater distances; however, due to the proximity of human settlements (120 m from the escarpment) and deforestation, the possibility of the blocks breaking off and impacting houses and people increases, causing considerable damage. This risk increases due to the fact that informal constructions continue to be built on the hillside (the "Ricardo Flores Magón" educational complex) and a dirt road cut located between the lower part of the dome and the residential area that connects with other neighborhoods located behind it, which means that there is continuous traffic of inhabitants and their recreational activities. Likewise, deforestation has exposed potentially unstable blocks, which, together with triggering events such as torrential rains and regional and local seismicity, increases the susceptibility to rock falls. Based on the statistical analysis and the field inventory, it is recommended that the larger unstable blocks be stabilized with anchors, prevent further construction by establishing a safety strip of at least 100 meters from the base of the escarpment, and carry out reforestation programs with forest plantations native to the region. Raise awareness among the population about the risks of rockfall events in the area and restrict access in order to prevent and mitigate any event that could occur due to this type of process.

Resumen El teratoma maduro es el subtipo de tumor de células germinales que incluye las tres capas germinales. La presentación más común en pediatría es extragonadal, en raras ocasiones se observan tumores de componente monodérmico, los cuales suelen presentarse a nivel gonadal. Se presenta el caso de una paciente adolescente de 13 años con un año de evolución con tumoración abdominal. Los estudios de ultrasonido, tomografía y resonancia evidenciaron tumor heterogéneo, con elevación discreta de CA-125, se realiza laparotomía y resección completa de la lesión (con un peso de 11.2 kg). Reporte histopatológico de teratoma maduro monodérmico.

Abstract The mature teratoma is the subtype of germ cell tumor that includes the three germ layers. The most common presentation in pediatrics is extragonadal, on rare occasions monodermal component tumors are observed, which usually present at the gonadal level. We present the case of a 13-year-old female adolescent patient with one year of evolution with abdominal tumor. Ultrasound, tomography and resonance studies showed heterogeneous tumor, with slight elevation of CA-125: laparotomy and complete resection of the lesion was performed, with a weight of 11.2 kg. Histopathological report: monodermal mature teratoma.

Resumen La caracterización de la vegetación sirve para generar directrices de manejo y conservación, sin embargo, pocos estudios en bosques templados integran a la vegetación del sotobosque. El objetivo del presente estudio fue describir la estructura, composición y diversidad florística arbórea, arbustiva y herbácea del bosque de pino-encino en un gradiente altitudinal en la comunidad de Miguel Hidalgo, San Antonio Huitepec, Oaxaca. Se tomaron variables dasométricas en 45 sitios distribuidos en tres intervalos altitudinales. Se estimaron la diversidad alfa y la beta, así como el índice de valor de importancia, y se compararonentre intervalos. Se identificaron 27 especies arbóreas, 25 arbustivas y 73 herbáceas. Se determinó una diversidad media, para arbóreas y herbáceas, y baja para arbustivas. La diversidad de las tres formas de vida no presentó un patrón de distribución definido; sin embargo, el intervalo altitudinal superior presentó el mayor valor promedio de área basal, altura y cobertura individual. Pinus oocarpa Schiede., Gaultheria erecta Vent. y Pteridium aquilinum var. feei (W. Schaffn. ex Fée) Maxon presentaron el valor más alto del índice de valor de importancia en el intervalo altitudinal inferior e intermedio y Pinus pseudostrobus Lindl. y Salvia cinnabarina M. Martens & Galeotti en el intervalo altitudinal superior. El intervalo altitudinal superior presentó mejor estado de conservación influenciado por una menor perturbación antropogénica. Considerar al sotobosque en estudios de caracterización mejora la comprensión de la dinámica de crecimiento y desarrollo de la vegetación forestal.

Abstract Characterization of the vegetation helps to generate management and conservation guidelines, however, few studies in temperate forests integrate the understory vegetation. The objective of this study was to describe the structure, composition, and tree, shrub, and herbaceous floristic diversity of the pine-oak forest in an altitudinal gradient in the community of Miguel Hidalgo, San Antonio Huitepec, Oaxaca. Dasometric variables were taken at 45 sites distributed in three altitudinal intervals. Alpha and beta diversity were estimated, as well as the importance value index, and compared among intervals. 27 tree species, 25 shrubs and 73 herbaceous were identified. A medium diversity was determined for trees and herbs, and low for shrubs. The diversity of the three life forms did not present a defined distribution pattern; however, the upper altitudinal interval presented the highest average value of basal area, height, and individual coverage. Pinus oocarpa Schiede., Gaultheria erecta Vent. and Pteridium aquilinum var. feei (W. Schaffn. ex Fée) Maxon presented the highest value of the importance value index in the lower and intermediate altitudinal range, and Pinus pseudostrobus Lindl. and Salvia cinnabarina M. Martens & Galeotti in the upper altitudinal range. The upper altitudinal interval presented a better state of conservation influenced by less anthropogenic disturbance. Considering the understory in characterization studies improves the understanding of the dynamics of growth and development of forest vegetation.

Abstract Objective: Generate recommendations for the diagnosis, management, and follow-up of chronic hyperkalemia. Method: This consensus was made by nephrologists and cardiologists following the GRADE methodology. Results: Chronic hyperkalemia can be defined as a biochemical condition with or without clinical manifestations characterized by a recurrent elevation of serum potassium levels that may require pharmacological and or non-pharmacological intervention. It can be classified as mild (K+ 5.0 to < 5.5 mEq/L), moderate (K+ 5.5 to 6.0 mEq/L) or severe (K+ > 6.0 mEq/L). Its incidence and prevalence have yet to be determined. Risk factors: chronic kidney disease, chronic heart failure, diabetes mellitus, age ≥ 65 years, hypertension, and drugs that inhibit the renin angiotensin aldosterone system (RAASi), among others. There is no consensus for the management of chronic hyperkalemia. The suggested pattern for patients is to identify and eliminate or control risk factors, provide advice on potassium intake and, for whom it is indicated, optimize RAASi therapy, administer oral potassium binders and correct metabolic acidosis. Conclusions: The recommendation is to pay attention to the diagnosis, management, and follow-up of chronic hyperkalemia, especially in patients with risk factors.

Resumen Objetivo: Generar recomendaciones para el diagnóstico, el manejo y el seguimiento de la hiperkalemia crónica. Método: Este consenso fue realizado por nefrólogos y cardiólogos siguiendo la metodología GRADE. Resultados: La hiperkalemia crónica puede definirse como una condición bioquímica, con o sin manifestaciones clínicas, caracterizada por una elevación recurrente de las concentraciones séricas de potasio que puede requerir una intervención farmacológica, no farmacológica o ambas. Puede clasificarse en leve (K+ 5,0 a < 5,5 mEq/l), moderada (K+ 5,5 a 6,0 mEq/l) o grave (K+ > 6,0 mEq/l). Su incidencia y prevalencia no han sido claramente determinadas. Se consideran factores de riesgo la enfermedad renal crónica, la insuficiencia cardiaca crónica, la diabetes mellitus, la edad ≥ 65 años, la hipertensión arterial y el tratamiento con inhibidores del sistema renina-angiotensina-aldosterona (iSRAA), entre otros. No hay consenso sobre el manejo de la hiperkalemia crónica. Se sugiere identificar y eliminar o controlar los factores de riesgo, brindar asesoramiento sobre la ingesta de potasio y, para quien esté indicado, optimizar la terapia con iSRAA, administrar aglutinantes orales del potasio y corregir la acidosis metabólica. Conclusiones: Se recomienda prestar atención al diagnóstico, el manejo y el seguimiento de la hiperkalemia crónica, en especial en los pacientes con factores de riesgo.

Abstract Background: Germination characteristics of grasses are the bases for explain possible adaptation to environmental changes, as well as invasive behavior. Hypotheses: Each species has germination characteristics that can explain its establishment success in grassland. Studied species: Bouteloua curtipendula, B. dactyloides, B. eriopoda, B. gracilis, B. hirsuta, B. repens, B. rigidiseta, Chloris virgata, Digitaria californica, Eragrostis curvula, E. echinochloidea, E. lehmanniana, E. superba, Heteropogon contortus, Hilaria mutica, Leptochloa dubia, Melinis repens, Muhlenbergia emersleyi, M. macroura, M. rigida, Pappophorum bicolor, and Pennisetum ciliare (16 native species and six exotic species). Study area and dates: Chihuahuan desert grasslands, 2019. Methods: Germination test at 28 °C at constant moisture and in the dark. Response variables were number of seed germinated, time of germination and length of root and shoot. Based on those, range, time, velocity, index of germination ad root:shoot ratio were calculated. Results: Germination range was ≤ 4 days on 18 species. The highest values (P < 0.05) were 7.8 germinated seed per day and 3.3 of germination index. Eleven species had a value ≤ 1 of R:S at one week age. Conclusions: E. curvula, B. curtipendula, L. dubia, and D. californica showed one or more adaptations that place them with potential for a rapid establishment in arid zones. However, the invasive aliens E. lehmanniana and Melinis repens possibly have other strategies that facilitate their establishment.

Resumen Antecedentes: Las características de germinación en gramíneas pueden ayudar a explicar la adaptación a cambios ambientales, así como comportamientos de invasión. Hipótesis: Cada especie tiene características de germinación que pueden explicar su éxito de establecimiento en pastizales naturales. Especies de estudio: Bouteloua curtipendula, B. dactyloides, B. eriopoda, B. gracilis, B. hirsuta, B. repens, B. rigidiseta, Chloris virgata, Digitaria californica, Eragrostis curvula, E. echinochloidea, E. lehmanniana, E. superba, Heteropogon contortus, Hilaria mutica, Leptochloa dubia, Melinis repens, Muhlenbergia emersleyi, M. macroura, M. rigida, Pappophorum bicolor y Pennisetum ciliare (16 especies nativas y seis exóticas). Sitio de estudio y fechas: Pastizales del Desierto Chihuahuense, 2019. Métodos: Pruebas de germinación a 28 °C, humedad constante y en obscuridad. Las variables cuantificadas fueron número de semillas germinadas, tiempo de germinación y longitud de raíz y tallo. Con base en esto se determinó: rango, tiempo, velocidad, índice de germinación y proporción raíz:tallo. Resultados: El rango de germinación fue ≤ 4 días en 18 especies. Los valores mas altos (P < 0.05) fueron 7.8 semillas por día y 3.3 de índice de germinación. Once de las especies presentaron valores ≤ 1 en R:T a la semana de crecimiento. Conclusiones: Las especies E. curvula, B. curtipendula, L. dubia y D. californica presentan valores que las ubican con potencial para su rápido establecimiento en zonas áridas. Sin embargo, las exóticas invasoras E. lehmanniana y Melinis repens posiblemente tienen otras estrategias que facilitan su establecimiento.

Abstract: Adults with complex congenital heart disease with univentricular physiology and decreased in the pulmonary flow constitute a therapeutic challenge, many of these patients are palliated with modified Blalock-Taussig shunt (mBTS). The mBTS can develop occlusion or stenosis over time with deterioration of functional class and poor exercise tolerance. Dysfunction of a mBTS is a life-threatening situation requiring urgent therapy. A new surgical palliation is a high-risk procedure, so stenting a mBTS can be an alternative. We report a 29-year-old female with tricuspid atresia and pulmonary infundibular stenosis palliated with mBTS with progressive cyanosis (oxygen saturation of 54%) and dyspnea; computed tomography revealed a stenosed mBTS, and an interventional percutaneous approach was made. The stenting of the mBTS was made with two stents (Express LD vascular 6 x 37 mm and 6 x 27 mm). Oxygen saturation post-procedure increase to 70-75%. Occlusion of these shunts are a common major complication, leading to a decrease in pulmonary perfusion with subsequent respiratory symptoms, low saturation and oxygenation, cyanosis, metabolic acidosis and can generate a life-threatening event if it occurs acutely. Stent implantation into a previous mBTS through cardiac catheterization can be an alternative to shunt operation in patients with cyanotic congenital heart disease having a good long-term results.

Resumen: Los adultos con cardiopatía congénita compleja, con fisiología univentricular y flujo pulmonar disminuido, constituyen un reto terapéutico. Muchos de ellos reciben tratamiento paliativo con fístula sistémico-pulmonar desde la etapa pediátrica. Dicha fístula puede presentar oclusión o estenosis y ocasionar deterioro de la capacidad funcional y clínica. Colocar una nueva fístula sistémico-pulmonar a través de una cirugía se considera de alto riesgo, por lo que el uso de stents a través de cateterismo cardíaco surge como una opción que ha tenido buenos resultados. Se describe el caso de un adulto con atresia tricúspide con fístula sistémico-pulmonar en la etapa pediátrica, quien acudió al servicio de urgencias por deterioro de su clase funcional y desaturación en aire ambiente de hasta un 64%; en la tomografía cardíaca se evidenció estenosis del tercio distal de la fístula sistémico-pulmonar, por lo que se decidió colocar, mediante cateterismo cardíaco intervencionista, dos stents (Express LD vascular 6 x 37 mm y 6 x 27 mm), luego de lo cual la saturación sistémica fue del 75%, por lo que se consideró exitosa la colocación de los dispositivos. La oclusión de estas fístulas es una complicación habitual, que genera disminución de la perfusión pulmonar con los subsecuentes síntomas respiratorios, disminución de la saturación y la oxigenación, cianosis y acidosis metabólica, y puede generar un evento que amenaza la vida si se presenta de manera aguda. La recanalización transcatéter de una fístula sistémico-pulmonar con stent es una alternativa adecuada para evitar un riesgo quirúrgico y arroja resultados óptimos.