Fístula Gastro-Esplénica por Linfoma: reporte de caso y revisión integrativa de la literatura

La fístula gastro-esplénica es una condición rara y potencialmente fatal causada, principalmente, por neoplasias.  Objetivos: Reportar un caso de fístula gastro-esplénica y realizar una revisión integrativa de la literatura. Caso clínico: Paciente mujer de 63 años, con cuadro de hiporexia, astenia, melena y masa abdominal de dos meses de evolución; internada por hematemesis masiva. Ante la imposibilidad de tratamiento endoscópico, se realizó una laparotomía exploradora de emergencia, donde se identificó un gran tumor esplénico que invadía la curvatura mayor gástrica. El abordaje quirúrgico incluyó gastrectomía segmentar con esplenectomía y cirugía de control de daños. El diagnóstico anatomo-patológico fue compatible con linfoma linfocítico de células pequeñas esplénico, fistulizado al estómago.  Discusión: La fístula gastro-esplénica es una entidad rara cuya principal causa son los tumores malignos, principalmente los linfomas de células grandes. La tomografía de abdomen es el examen de elección para el diagnóstico. El tratamiento definitivo, en la mayoría de los casos, consiste en la gastrectomía parcial, con o sin esplenectomía

Basin-wide variation in tree hydraulic safety margins predicts the carbon balance of Amazon forests

Tropical forests face increasing climate risk1,2, yet our ability to predict their response to climate change is limited by poor understanding of their resistance to water stress. Although xylem embolism resistance thresholds (for example, Ψ50) and hydraulic safety margins (for example, HSM50) are important predictors of drought-induced mortality risk3–5, little is known about how these vary across Earth’s largest tropical forest. Here, we present a pan-Amazon, fully standardized hydraulic traits dataset and use it to assess regional variation in drought sensitivity and hydraulic trait ability to predict species distributions and long-term forest biomass accumulation. Parameters Ψ50 and HSM50 vary markedly across the Amazon and are related to average long-term rainfall characteristics. Both Ψ50 and HSM50 influence the biogeographical distribution of Amazon tree species. However, HSM50 was the only significant predictor of observed decadal-scale changes in forest biomass. Old-growth forests with wide HSM50 are gaining more biomass than are low HSM50 forests. We propose that this may be associated with a growth–mortality trade-off whereby trees in forests consisting of fast-growing species take greater hydraulic risks and face greater mortality risk. Moreover, in regions of more pronounced climatic change, we find evidence that forests are losing biomass, suggesting that species in these regions may be operating beyond their hydraulic limits. Continued climate change is likely to further reduce HSM50 in the Amazon6,7, with strong implications for the Amazon carbon sink

The number of tree species on Earth.

One of the most fundamental questions in ecology is how many species inhabit the Earth. However, due to massive logistical and financial challenges and taxonomic difficulties connected to the species concept definition, the global numbers of species, including those of important and well-studied life forms such as trees, still remain largely unknown. Here, based on global ground-sourced data, we estimate the total tree species richness at global, continental, and biome levels. Our results indicate that there are ∼73,000 tree species globally, among which ∼9,000 tree species are yet to be discovered. Roughly 40% of undiscovered tree species are in South America. Moreover, almost one-third of all tree species to be discovered may be rare, with very low populations and limited spatial distribution (likely in remote tropical lowlands and mountains). These findings highlight the vulnerability of global forest biodiversity to anthropogenic changes in land use and climate, which disproportionately threaten rare species and thus, global tree richness

The number of tree species on Earth.

One of the most fundamental questions in ecology is how many species inhabit the Earth. However, due to massive logistical and financial challenges and taxonomic difficulties connected to the species concept definition, the global numbers of species, including those of important and well-studied life forms such as trees, still remain largely unknown. Here, based on global ground-sourced data, we estimate the total tree species richness at global, continental, and biome levels. Our results indicate that there are ∼73,000 tree species globally, among which ∼9,000 tree species are yet to be discovered. Roughly 40% of undiscovered tree species are in South America. Moreover, almost one-third of all tree species to be discovered may be rare, with very low populations and limited spatial distribution (likely in remote tropical lowlands and mountains). These findings highlight the vulnerability of global forest biodiversity to anthropogenic changes in land use and climate, which disproportionately threaten rare species and thus, global tree richness

Basin-wide variation in tree hydraulic safety margins predicts the carbon balance of Amazon forests

This is the final version. Available on open access from Nature Research via the DOI in this recordData availability: The pan-Amazonian HT dataset (Ψ 50, Ψ dry and HSM50) and branch wood density per species per site, as well as forest dynamic and climate data per plot presented in this study are available as a ForestPlots.net data package at https://forestplots.net/data-packages/Tavares-et-al-2023. Basal area weighted mean LMA is shown in Supplementary Table 2. Species stem wood density data were obtained from Global Wood Density database65,66. Species WDA data were extracted from ref. 45.Code availability: The codes to recreate the main analyses and the main figures presented in this study are available as a ForestPlots.net data package at https://forestplots.net/data-packages/Tavares-et-al-2023.Tropical forests face increasing climate risk, yet our ability to predict their response to climate change is limited by poor understanding of their resistance to water stress. Although xylem embolism resistance thresholds (for example, Ψ 50) and hydraulic safety margins (for example, HSM50) are important predictors of drought-induced mortality risk, little is known about how these vary across Earth’s largest tropical forest. Here, we present a pan-Amazon, fully standardized hydraulic traits dataset and use it to assess regional variation in drought sensitivity and hydraulic trait ability to predict species distributions and long-term forest biomass accumulation. Parameters Ψ 50 and HSM50 vary markedly across the Amazon and are related to average long-term rainfall characteristics. Both Ψ 50 and HSM50 influence the biogeographical distribution of Amazon tree species. However, HSM50 was the only significant predictor of observed decadal-scale changes in forest biomass. Old-growth forests with wide HSM50 are gaining more biomass than are low HSM50 forests. We propose that this may be associated with a growth–mortality trade-off whereby trees in forests consisting of fast-growing species take greater hydraulic risks and face greater mortality risk. Moreover, in regions of more pronounced climatic change, we find evidence that forests are losing biomass, suggesting that species in these regions may be operating beyond their hydraulic limits. Continued climate change is likely to further reduce HSM50 in the Amazon, with strong implications for the Amazon carbon sink

Biodiversidad en la cuenca baja del Putumayo, Perú

La cuenca baja del río Putumayo, en la Amazonía peruana, ha sido un área históricamente afectada por actividades ilegales, pero destaca por su excepcional biodiversidad y comunidades indígenas murui-muinani de Remanso y Tres Esquinas. Este estudio se enfocó en la cuenca baja del Putumayo para proporcionar información valiosa. El libro presenta resultados de estudios sobre vegetación, flora, anfibios, reptiles, aves, mamíferos, uso de la biodiversidad y actividades económicas. Se utilizaron diversos métodos, incluyendo parcelas para plantas, transectos para anfibios y reptiles, y avistamientos para aves. También se realizaron entrevistas en las comunidades locales. El análisis de la biodiversidad incluyó la evaluación de la riqueza, dominancia y abundancia de especies, así como la similitud entre hábitats. Se identificaron diferentes unidades de vegetación con al menos 372 especies de plantas, incluyendo posibles especies nuevas y vulnerables. En el estudio herpetológico, se observó que la riqueza esperada de especies en terraza media y alta fue similar. Se registraron especies de ranas terrestres dominantes, y se identificó una posible especie nueva. La evaluación ornitológica reveló 261 especies de aves, algunas sensibles y registros de especies no reportadas previamente. En el estudio de mamíferos se registraron 35 especies, con diferencias en la abundancia y biomasa en bosque inundable y tierra firme. Las principales actividades en las comunidades de Remanso y Tres Esquinas fueron pesca, agricultura, caza y tala selectiva. La caza de animales se realizó intensivamente. En resumen, la cuenca baja del Putumayo es rica en biodiversidad, pero las actividades humanas plantean desafíos para su conservación. Se requieren acciones inmediatas para garantizar la sostenibilidad de estos recursos y los beneficios para las comunidades locales.Revisión por pares

Biodiversidad en las cuencas del Napo y Curaray, Perú

Las cuencas altas del Curaray y Napo presentan poblaciones saludables de flora y fauna en comparación al resto de la Amazonía peruana. La cuenca del Nashiño tiene peculiaridades que la convierten en una zona de enorme importancia de conservación y puede ser complementaria a la Reserva Comunal Airo Pai. La cuenca del Nashiño alberga las poblaciones más grandes de Lagothrix lagotricha poeppigii y es el único refugio de Leontocebus tripartus. Además tiene meandros abandonados con gran biodiversidad de peces de valor comercial para los pobladores locales. Por esta razón, para evitar la degradación gradual de la cuenca del Nashiño como producto de la tragedia de los bienes comunes, es necesario crear una estrategia de conservación acorde a los potenciales de biodiversidad y al uso actual de las comunidades indígenas kichwa, de tal forma que se garantice la conservación de biodiversidad y supervivencia de los pueblos indígenas quienes usualmente están olvidados en las políticas de desarrollo. Es urgente la creación o ampliación de un área reservada para proteger esta posible fuente de muchas especies de fauna silvestre del departamento de Loreto. La conservación de la cuenca del Nashiño tiene jusficación biológica, social, económica y cultural.Revisión por pares