Climate change increases threat to plant diversity in tropical forests of Central America and southern Mexico.

Global biodiversity is negatively affected by anthropogenic climate change. As species distributions shift due to increasing temperatures and precipitation fluctuations, many species face the risk of extinction. In this study, we explore the expected trend for plant species distributions in Central America and southern Mexico under two alternative Representative Concentration Pathways (RCPs) portraying moderate (RCP4.5) and severe (RCP8.5) increases in greenhouse gas emissions, combined with two species dispersal assumptions (limited and unlimited), for the 2061-2080 climate forecast. Using an ensemble approach employing three techniques to generate species distribution models, we classified 1924 plant species from the region's (sub)tropical forests according to IUCN Red List categories. To infer the spatial and taxonomic distribution of species' vulnerability under each scenario, we calculated the proportion of species in a threat category (Vulnerable, Endangered, Critically Endangered) at a pixel resolution of 30 arc seconds and by family. Our results show a high proportion (58-67%) of threatened species among the four experimental scenarios, with the highest proportion under RCP8.5 and limited dispersal. Threatened species were concentrated in montane areas and avoided lowland areas where conditions are likely to be increasingly inhospitable. Annual precipitation and diurnal temperature range were the main drivers of species' relative vulnerability. Our approach identifies strategic montane areas and taxa of conservation concern that merit urgent inclusion in management plans to improve climatic resilience in the Mesoamerican biodiversity hotspot. Such information is necessary to develop policies that prioritize vulnerable elements and mitigate threats to biodiversity under climate change.

Effect of school reopening on pediatric morbidity and mortality during the third epidemiological wave of COVID-19 in a Mexican state / Efecto de la reapertura de escuelas en la morbimortalidad pediátrica durante la tercera ola epidemiológica por COVID-19 en un estado mexicano

Abstract Background: Determining the effect of reopening schools on pediatric SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) infection rates increased the need to share the experience of governments in many geographic regions for better future decision-making in similar health emergencies. Methods: Through a prospective study based on a population-based cohort, students from 18,988 schools in the State of Mexico who began returning to school were followed. Daily sanitation filters were implemented in each school and district liaisons were informed on a daily basis through a negative network. Identified cases were confirmed by reverse transcriptase-polymerase chain reaction. Simple case frequencies, percentages, and incidences of COVID-19 were estimated. State incidences were compared with the national incidence. Results: A total of 3,586 cases were confirmed; 2,048 (57.1%) were children. Twenty-four (0.6%) were hospitalized for moderate to severe COVID-19; nine (37.5%) died, and only one was a schoolchild. From week 36, an average infection rate of 0.36 was observed. The highest infection rate in schoolchildren was observed in epidemiologic week 40 (1.01); from this week on, a decrease in the number of cases was observed until week 50. Conclusions: The use of non-pharmaceutical interventions has more advantages than limitations, as long as the strategies are homogeneous and properly implemented to ensure adequate control of infections.

Resumen Introducción: La determinación del efecto de reabrir las escuelas sobre las tasas de infección pediátrica por SARS-CoV-2 (síndrome respiratorio agudo grave coronavirus 2) incrementó la necesidad de trasmitir la experiencia de los gobiernos de muchas regiones geográficas para mejores decisiones futuras en emergencias sanitarias similares. Métodos: Mediante un estudio prospectivo basado en una cohorte poblacional se dio seguimiento a los alumnos de 18,988 escuelas del Estado de México que iniciaron con el regreso a clases. Se implementaron filtros sanitarios diarios en cada escuela y cotidianamente se informaban a los enlaces jurisdiccionales a través de una red negativa. Los casos identificados eran confirmados a través de RT-PCR (reacción en cadena de la polimerasa con transcriptasa inversa). Se estimaron frecuencias simples de casos, porcentajes e incidencias de COVID-19. Las incidencias del estado se compararon con la incidencia nacional. Resultados: Un total de 3,586 casos fueron confirmados; 2,048 (57.1%) correspondieron a niños. Veinticuatro (0.6%) fueron hospitalizados por COVID-19 moderado a grave; nueve (37.5%) fallecieron, y solamente una correspondió a un escolar. A partir de la semana 36 se observó una tasa promedio de infecciones de 0.36. En la semana epidemiológica 40 se observó la mayor tasa de infección en escolares (1.01); a partir de esta semana se observa un declive de los casos hasta la semana 50. Conclusiones: La implementación de intervenciones no farmacéuticas tiene más ventajas que limitaciones, siempre y cuando las estrategias sean homogéneas y correctamente ejecutadas, lo que asegurará un adecuado control en los contagios.

Effect of school reopening on pediatric morbidity and mortality during the third epidemiological wave of COVID-19 in a Mexican state.

BACKGROUND: Determining the effect of reopening schools on pediatric SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) infection rates increased the need to share the experience of governments in many geographic regions for better future decision-making in similar health emergencies. METHODS: Through a prospective study based on a population-based cohort, students from 18,988 schools in the State of Mexico who began returning to school were followed. Daily sanitation filters were implemented in each school and district liaisons were informed on a daily basis through a negative network. Identified cases were confirmed by reverse transcriptase-polymerase chain reaction. Simple case frequencies, percentages, and incidences of COVID-19 were estimated. State incidences were compared with the national incidence. RESULTS: A total of 3,586 cases were confirmed; 2,048 (57.1%) were children. Twenty-four (0.6%) were hospitalized for moderate to severe COVID-19; nine (37.5%) died, and only one was a schoolchild. From week 36, an average infection rate of 0.36 was observed. The highest infection rate in schoolchildren was observed in epidemiologic week 40 (1.01); from this week on, a decrease in the number of cases was observed until week 50. CONCLUSIONS: The use of non-pharmaceutical interventions has more advantages than limitations, as long as the strategies are homogeneous and properly implemented to ensure adequate control of infections.

INTRODUCCIÓN: La determinación del efecto de reabrir las escuelas sobre las tasas de infección pediátrica por SARS-CoV-2 (síndrome respiratorio agudo grave coronavirus 2) incrementó la necesidad de trasmitir la experiencia de los gobiernos de muchas regiones geográficas para mejores decisiones futuras en emergencias sanitarias similares. MÉTODOS: Mediante un estudio prospectivo basado en una cohorte poblacional se dio seguimiento a los alumnos de 18,988 escuelas del Estado de México que iniciaron con el regreso a clases. Se implementaron filtros sanitarios diarios en cada escuela y cotidianamente se informaban a los enlaces jurisdiccionales a través de una red negativa. Los casos identificados eran confirmados a través de RT-PCR (reacción en cadena de la polimerasa con transcriptasa inversa). Se estimaron frecuencias simples de casos, porcentajes e incidencias de COVID-19. Las incidencias del estado se compararon con la incidencia nacional. RESULTADOS: Un total de 3,586 casos fueron confirmados; 2,048 (57.1%) correspondieron a niños. Veinticuatro (0.6%) fueron hospitalizados por COVID-19 moderado a grave; nueve (37.5%) fallecieron, y solamente una correspondió a un escolar. A partir de la semana 36 se observó una tasa promedio de infecciones de 0.36. En la semana epidemiológica 40 se observó la mayor tasa de infección en escolares (1.01); a partir de esta semana se observa un declive de los casos hasta la semana 50. CONCLUSIONES: La implementación de intervenciones no farmacéuticas tiene más ventajas que limitaciones, siempre y cuando las estrategias sean homogéneas y correctamente ejecutadas, lo que asegurará un adecuado control en los contagios.

Active alcohol consumption is associated with acute-on-chronic liver failure in Hispanic patients.

BACKGROUND: Acute-on-chronic liver failure (ACLF) is a severe clinical entity associated with elevated short-term mortality. We aimed to characterize patients with decompensated cirrhosis according to presence of ACLF, their association with active alcohol intake, and long-term survival in Latin America. METHODS: Retrospective cohort study of decompensated cirrhotic in three Chilean university centers (2017-2019). ACLF was diagnosed according EASL-CLIF criteria. We assessed survival using competing-risk and time-to-event analyses. We evaluated the time to death using accelerated failure time (AFT) models. RESULTS: We included 320 patients, median age of 65.3±11.7 years old, and 48.4% were women. 92 (28.7%) patients met ACLF criteria (ACLF-1: 29.3%, ACLF-2: 27.1%, and ACLF-3: 43.4%). The most common precipitants were infections (39.1%), and the leading organ failure was kidney (59.8%). Active alcohol consumption was frequent (27.7%), even in patients with a prior diagnosis of non-alcoholic fatty liver disease (NAFLD) (16.2%). Ninety-two (28.7%) patients had ACLF (ACLF-1: 8.4%, ACLF-2: 7.8%, and ACLF-3: 12.5%). ACLF patients had a higher MELD-Na score at admission (27 [22-31] versus 16 [12-21], p<0.0001), a higher frequency of alcohol-associated liver disease (36.7% versus 24.9%, p=0.039), and a more frequent active alcohol intake (37.2% versus 23.8%, p=0.019). In a multivariate model, ACLF was associated with higher mortality (subdistribution hazard ratio 1.735, 95%CI: 1.153-2.609; p<0.008). In the AFT models, the presence of ACLF during hospitalization correlated with a shorter time to death: ACLF-1 shortens the time to death by 4.7 times (time ratio [TR] 0.214, 95%CI: 0.075-0.615; p<0.004), ACLF-2 by 4.4 times (TR 0.224, 95%CI: 0.070-0.713; p<0.011), and ACLF-3 by 37 times (TR 0.027, 95%CI: 0.006-0.129; p<0.001). CONCLUSIONS: Patients with decompensated cirrhosis and ACLF exhibited a high frequency ofactive alcohol consumption. Patients with ACLF showed higher mortality and shorter time todeath than those without ACLF.

Alcohol Consumption: Medical Implications, the Liver and Beyond.

Alcohol consumption represents a major factor of morbidity and mortality, with a wide range of adverse medical implications that practically affect every organ system. It is the fifth major cause of deaths in men and women and causes up to 139 million disability-adjusted life years. Solid evidence places the risk as undoubtedly correlated to the length of time and amount of alcohol consumption. While alcohol-related liver disease represents one of the most studied and well-known consequences of alcohol use, the term itself embodies a wide spectrum of progressive disease stages that are responsible for almost half of the liver-related mortality worldwide. We discuss the staged alcohol-related fatty liver, alcohol-related steatohepatitis and, finally, fibrosis and cirrhosis, which ultimately may end up in a hepatocellular carcinoma. Other comorbidities such as acute and chronic pancreatitis; central nervous system; cardiovascular, respiratory and endocrine system; renal disease; urological pathologies; type 2 diabetes mellitus and even infectious diseases are reviewed in their relation to alcohol consumption. This article reviews the impact of alcohol use on different systems and organs, summarizing available evidence regarding its medical implications. It examines current basic and clinical data regarding mechanisms to highlight factors and processes that may be targetable to improve patient outcomes. Although alcohol use is a part of many cultural and social practices, as healthcare providers we must identify populations at high risk of alcohol abuse, educate patients about the potential alcohol-related harm and provide appropriate treatment.

csiLSFM combines light-sheet fluorescence microscopy and coherent structured illumination for a lateral resolution below 100 nm.

Light-sheet-based fluorescence microscopy (LSFM) features optical sectioning in the excitation process. It minimizes fluorophore bleaching as well as phototoxic effects and provides a true axial resolution. The detection path resembles properties of conventional fluorescence microscopy. Structured illumination microscopy (SIM) is attractive for superresolution because of its moderate excitation intensity, high acquisition speed, and compatibility with all fluorophores. We introduce SIM to LSFM because the combination pushes the lateral resolution to the physical limit of linear SIM. The instrument requires three objective lenses and relies on methods to control two counterpropagating coherent light sheets that generate excitation patterns in the focal plane of the detection lens. SIM patterns with the finest line spacing in the far field become available along multiple orientations. Flexible control of rotation, frequency, and phase shift of the perfectly modulated light sheet are demonstrated. Images of beads prove a near-isotropic lateral resolution of sub-100 nm. Images of yeast endoplasmic reticulum show that coherent structured illumination (csi) LSFM performs with physiologically relevant specimens.

[Treatment of thoracic disc herniation. Case report]. / Tratamiento de hernia discal torácica. Reporte de 2 casos.

BACKGROUND: Herniated thoracic intervertebral disc is a rare cause of spinal cord compression. Its frequency varies from 0.15% to 1.7% of all disc herniations, and produces symptoms in 0.5% to 0.8%. CLINICAL CASES: Case 1. A 50-year-old woman, with pain and burning sensation in left hemithorax of four months of onset. It was treated as a herpetic syndrome, with no improvement. She was seen after thirteen days of exacerbation of clinical symptoms. The physical examination showed asymmetric paraparesis, lower left pelvic limb 1/5, and right pelvic limb 3/5¸ sensory level T8, with left Babinski positive. A thoracic disc herniation in space T8-T9 was diagnosed. CASE 2: A 55-year-old patient with a history of presenting pain in lumbar area of 5 years onset. She also had radicular pain that radiated to the right pelvic limb, with intensity 10/10 on a Visual Analogue Scale. Her physical examination showed muscle strength 5/5, with normal sensitivity in all dermatomes and tendon reflexes, and a positive right Babinski. Thoracic disc herniation T7-T8 level was diagnosed. DISCUSSION: Due to anatomical conditions that define this type of hernia, the extracavitary posterolateral approach should be the recommended surgical procedure when the simultaneously performed anterior decompression and fixation with posterior instrumentation are the treatments proposed. CONCLUSION: Despite the different anatomical structures of this special area, it was possible to obtain satisfactory results for both clinical cases.

Estimating particle exposure in the Mexico City metropolitan area.

STUDY QUESTION: We examined whether methods for measuring exposure to airborne particles less than 10 microm in aerodynamic diameter (PM10) in the Mexico City metropolitan area give different estimates of PM10 levels, and the nature of these differences, and developed a model for estimating missing PM10 data for one measurement method. METHODS: Government PM10 measurements using two different technologies at five sites (the Sierra-Anderson PM10 High-Volume Air Sampler System, Hi-Vol) (every sixth day) and the Rupprecht and Patashnik Tapered Element Oscillating Microbalance (TEOM) monitor (daily), as well as Harvard Impactor (HI) data collected for research purposes from one monitoring station were matched by day and monitoring site, then compared visually and with basic descriptive statistics. We fit linear regression models with airport visual range measurements, meteorological data, and information on other air pollutants to predict the Hi-Vol measured PM10 levels for those days when direct measurements were not available. RESULTS: We found relatively low correlations (r ranging from 0.46 to 0.63) between PM10 measured with the TEOM and Hi-Vol methods, and highly variable differences (0-70 microg/m(3)) between the means of these measurements, depending on monitoring site. The HI measurements had a relatively high correlation with the Hi-Vol measurements (r=0.90). The models developed for the missing Hi-Vol measurements provided a series of estimated values similar to the actual Hi-Vol measurements, although the estimated series did not have high values in the range observed in the measured data. CONCLUSIONS: The differences we observed in the PM10 measurements across methods in Mexico City may be important when studying health effects associated with particle exposure, evaluating method performance under conditions and operating protocols similar to those in Mexico City, and determining compliance with air quality standards. The estimated series of PM10 measures may be a useful index of exposure for use in studies of the effects of air pollution on health.

Los efectos agudos de la contaminación del aire en la salud de la población: evidencias de estudios epidemiológicos / Acute effect of air pollution on health: Evidence from epidemiological studies

Objetivo. Sintetizar las evidencias de los efectos en la salud de la población por la exposición a contaminación del aire por ozono y partículas suspendidas. Material y métodos. A partir de las principales publicaciones internacionales y mexicanas, publicadas y referidas hasta junio del año 2000, se realizó un metanálisis para resumir los efectos reportados a través del empleo de modelos de efectos aleatorios. Resultados. Los resultados se expresaron como porcentajes de incremento por 10 unidades de concentración de PM10 (µg/m3) y ozono (ppb). Entre los efectos de PM10 cabe destacar el efecto agudo en la mortalidad (0.96 por ciento), hospitalizaciones (1.39 por ciento), visitas a salas de urgencias (3.11 por ciento), síntomas respiratorios (7.72 por ciento), parámetros de función pulmonar (1.42 por ciento), para capacidad vital forzada (CVF) y días de actividad restringida (7.74 por ciento). Los efectos de la exposición a ozono son igualmente significativos. Conclusiones. Estos resultados muestran el gran impacto que las concentraciones de contaminantes del aire podrían tener en la salud de las poblaciones urbanas de las grandes metrópolis. El texto completo en inglés de este artículo está disponible en: http://www.insp.mx/salud/index.html

Dificultades en los métodos de estudio de exposiciones ambientales y defectos del tubo neural / Methodological challenges to assess environmental exposure related to neural tube defects

Objetivo. Discutir las actitudes en la evaluación de las exposiciones ambientales como factores de riesgo para defectos de riesgo del tubo neural, al tiempo que se presentan los principales factores estudiados hasta la fecha. Resultados. Las exposiciones ambientales se citan muy a menudo como causa de malformaciones congénitas; sin embargo, ha sido difícil establecer esta asociación en los estudios de poblaciones humanas, debido a problemas en su diseño y conducción. Lo anterior es particularmente marcado en el caso del estudio de los defectos del cierre del tubo neural (DTN), que es una de las principales malformaciones y que incluye anencefalia, espina bífida y encefalocele, y su asociación con exposiciones ambientales. Las dificultades en los métodos surgen de: a) la medida de frecuencia para realizar comparaciones espacio-temporales; b) la clasificación y heterogeneidad de las malformaciones; c) la consideración de los factores relacionados con la madre, el padre y el producto, de manera conjunta, y d) la evaluación de las exposiciones ambientales. Conclusiones. Hipotéticamente las exposiciones ambientales tanto del padre como de la madre pueden producir daño genético antes y/o después de la concepción por la acción directa sobre el embrión o sobre el complejo fetoplacentario, de tal manera que en la evaluación de exposiciones ambientales: a) deben tomarse en cuenta las exposiciones maternas y paternas; b) debe considerarse el periodo crítico de exposición, esto es, tres meses anteriores a la concepción para el padre y un mes alrededor de la concepción para la madre; c) en la medida de lo posible, la evaluación de la exposición deberá ser cuantitativa, evitando clasificar a los grupos únicamente como expuestos y no expuestos, y d) es recomendable emplear marcadores biológicos de exposición siempre que sea posible, así como utilizar marcadores biológicos que permitan clasificar a la población en grupos con distinta susceptibilidad genética

Enfermedad del criador de palomas: presentación de cinco casos / Pigeon breeder's disease: report of 5 patients

En este trabajo se describen las manifestaciones clínicas y de laboratorio de cinco pacientes con la Enfermedad del Criador de Palomas, los cuales fueron diagnosticados y atendidos en nuestro Hospital en los últimos dos años. Se hace énfasis en las diferentes formas de presentación clínica, así como la importancia que tiene el estudio serológico para el diagnóstico, al demostrarse la presencia de anticuerpos precipitantes en el suelo de estos pacientes en contra de antígenos presentes en el suero y en las excretas de las palomas. En uno de los casos, tuvimos la oportunidad además de estudiar a varios de sus familiares. Clínicamente nuestros pacientes tuvieron una evolución crónica (promedio 27.4 meses) lo que sugiere exposición prolongada a los antígenos aviarios y la falta de diagnóstico oportuno. Serológicamente, en los cinco pacientes detectamos la presencia de anticuerpos precipitantes en contra de antígenos de paloma. En los familiares del caso estudiado, aunque clínicamente estaban asintomáticos, en tres de los nueve encontramos los mismos anticuerpos precipitantes, por lo que consideramos la posibilidad de que algunos factores genéticos pueden ser importantes en la expresión de la respuesta inmune humoral a los antígenos aviarios, que ocurre en esta forma de neumonitis por hipersensibilidad

Meningiomas: aspectos actuales y perspectivas / Meningioma: present aspects and perspectives

Los autores reportan una serie de 60 pacientes consecutivos sometidos a tratamiento quirúrgico para meningiomas. Analizan los factores que influyen de manera determinante sobre las tasas de morbilidad y mortalidad en nuestro medio, además de conocer grado de resección quirúrgica alcanzada de acuerdo a la clasificación de Simpson. Los resultados obtenidos muestran que las tasas de morbilidad y mortalidad estan principalmente relacionadas con la edad del paciente, tamaño de la tumoración al momento de efectuar el diagnóstico, grado de resección quirúrgica y secundarimanete su histopatología