14 research outputs found
Supervivencia de pacientes con cáncer de ovario. Hospital Gineco-Obstétrico “Ramón González Coro” 2001-2013.
Introduction: Ovarian cancer has a high mortality only preceded by breast cancer and, excluding these cancers, is the leading cause of death due to gynecological cancer, although its frequency is lower than that of cancers of the uterus. Objective: To determine the survival curves according to the stage of cancer and the relapse of the disease.Material and method: An observational, retrospective study of patients with ovarian cancer treated at the Hospital "Ramón González Coro" was carried out. The universe consisted of 98 patients who received medical care between 2001 and 2013. Survival was calculated using the Kaplan-Meier curve and Cox regression.Results: Women with stage III or IV disease had an average survival of 36 months, with a minimum and maximum of 6 and 48 months, respectively. The greatest survival was obtained for those in which there was no relapse in which the survival was 3.4 times longer than in the others. Overall comparisons using the Breslow test (Wilcoxon generalized) showed that survival differences were highly significant (p <0.001) in relapse.Conclusion: There was no significant association between treatments, types of cancer and survival. Cancer stages and relapse of the disease were the only variables that were significantly associated with post-treatment survival.Introducción: El cáncer de ovario tiene una alta mortalidad sólo precedida por el cáncer de mama y, excluyendo esos cánceres, es la primera causa de muerte por cáncer ginecológico a pesar de que su frecuencia es menor que la de los cánceres de útero. Objetivo: Determinar las curvas de supervivencia según el estadio del cáncer y la recaída de la enfermedad.Material y método: Se realizó un estudio observacional, retrospectivo, de pacientes con cáncer de ovario atendidas en el Hospital “Ramón González Coro”. El universo estuvo constituido por las 98 pacientes que recibieron atención médica entre 2001 y 2013. La supervivencia se calculó mediante curva de Kaplan-Meier y regresión de Cox.Resultados: Las mujeres que tenían la enfermedad en estadios III o IV tuvieron un promedio de sobre vida de 36 meses, con un mínimo y máximo de 6 y 48 meses, respectivamente. La mayor sobrevida se obtuvo para aquellas en que no hubo recaída en las que la sobrevida fue 3.4 veces más larga que en las otras. Las comparaciones globales mediante el test de Breslow (Wilcoxon generalizado) mostró que las diferencias de supervivencia fueron altamente significativas (p<0.001) en la recaída.Conclusión: No se obtuvo asociación significativa entre los tratamientos, los tipos de cáncer y la supervivencia. Los estadios del cáncer y la recaída de la enfermedad fueron las únicas variables que se asociaron significativamente con la supervivencia post tratamiento
Carbon sequestration potential of second-growth forest regeneration in the Latin American tropics
Regrowth of tropical secondary forests following complete or nearly complete removal of forest vegetation actively stores carbon in aboveground biomass, partially counterbalancing carbon emissions from deforestation, forest degradation, burning of fossil fuels, and other anthropogenic sources. We estimate the age and spatial extent of lowland second-growth forests in the Latin American tropics and model their potential aboveground carbon accumulation over four decades. Our model shows that, in 2008, second-growth forests (1 to 60 years old) covered 2.4 million km2 of land (28.1%of the total study area).Over 40 years, these lands can potentially accumulate a total aboveground carbon stock of 8.48 Pg C (petagrams of carbon) in aboveground biomass via low-cost natural regeneration or assisted regeneration, corresponding to a total CO2 sequestration of 31.09 Pg CO2. This total is equivalent to carbon emissions from fossil fuel use and industrial processes in all of Latin America and the Caribbean from1993 to 2014. Ten countries account for 95% of this carbon storage potential, led by Brazil, Colombia, Mexico, and Venezuela. We model future land-use scenarios to guide national carbon mitigation policies. Permitting natural regeneration on 40% of lowland pastures potentially stores an additional 2.0 Pg C over 40 years. Our study provides information and maps to guide national-level forest-based carbon mitigation plans on the basis of estimated rates of natural regeneration and pasture abandonment. Coupled with avoided deforestation and sustainable forestmanagement, natural regeneration of second-growth forests provides a low-costmechanism that yields a high carbon sequestration potential with multiple benefits for biodiversity and ecosystem services. © 2016 The Authors
Biodiversity recovery of Neotropical secondary forests
Old-growth tropical forests harbor an immense diversity of tree species but are rapidly being cleared, while secondary forests that regrow on abandoned agricultural lands increase in extent. We assess how tree species richness and composition recover during secondary succession across gradients in environmental conditions and anthropogenic disturbance in an unprecedented multisite analysis for the Neotropics. Secondary forests recover remarkably fast in species richness but slowly in species composition. Secondary forests take a median time of five decades to recover the species richness of old-growth forest (80% recovery after 20 years) based on rarefaction analysis. Full recovery of species composition takes centuries (only 34% recovery after 20 years). A dual strategy that maintains both old-growth forests and species-rich secondary forests is therefore crucial for biodiversity conservation in human-modified tropical landscapes. Copyright © 2019 The Authors, some rights reserved
Genomic investigations of unexplained acute hepatitis in children
Since its first identification in Scotland, over 1,000 cases of unexplained paediatric hepatitis in children have been reported worldwide, including 278 cases in the UK1. Here we report an investigation of 38 cases, 66 age-matched immunocompetent controls and 21 immunocompromised comparator participants, using a combination of genomic, transcriptomic, proteomic and immunohistochemical methods. We detected high levels of adeno-associated virus 2 (AAV2) DNA in the liver, blood, plasma or stool from 27 of 28 cases. We found low levels of adenovirus (HAdV) and human herpesvirus 6B (HHV-6B) in 23 of 31 and 16 of 23, respectively, of the cases tested. By contrast, AAV2 was infrequently detected and at low titre in the blood or the liver from control children with HAdV, even when profoundly immunosuppressed. AAV2, HAdV and HHV-6 phylogeny excluded the emergence of novel strains in cases. Histological analyses of explanted livers showed enrichment for T cells and B lineage cells. Proteomic comparison of liver tissue from cases and healthy controls identified increased expression of HLA class 2, immunoglobulin variable regions and complement proteins. HAdV and AAV2 proteins were not detected in the livers. Instead, we identified AAV2 DNA complexes reflecting both HAdV-mediated and HHV-6B-mediated replication. We hypothesize that high levels of abnormal AAV2 replication products aided by HAdV and, in severe cases, HHV-6B may have triggered immune-mediated hepatic disease in genetically and immunologically predisposed children
Strong floristic distinctiveness across Neotropical successional forests
International audienceForests that regrow naturally on abandoned fields are important for restoring biodiversity and ecosystem services, but can they also preserve the distinct regional tree floras? Using the floristic composition of 1215 early successional forests (≤20 years) in 75 human-modified landscapes across the Neotropic realm, we identified 14 distinct floristic groups, with a between-group dissimilarity of 0.97. Floristic groups were associated with location, bioregions, soil pH, temperature seasonality, and water availability. Hence, there is large continental-scale variation in the species composition of early successional forests, which is mainly associated with biogeographic and environmental factors but not with human disturbance indicators. This floristic distinctiveness is partially driven by regionally restricted species belonging to widespread genera. Early secondary forests contribute therefore to restoring and conserving the distinctiveness of bioregions across the Neotropical realm, and forest restoration initiatives should use local species to assure that these distinct floras are maintained
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Strong floristic distinctiveness across Neotropical successional forests.
Forests that regrow naturally on abandoned fields are important for restoring biodiversity and ecosystem services, but can they also preserve the distinct regional tree floras? Using the floristic composition of 1215 early successional forests (≤20 years) in 75 human-modified landscapes across the Neotropic realm, we identified 14 distinct floristic groups, with a between-group dissimilarity of 0.97. Floristic groups were associated with location, bioregions, soil pH, temperature seasonality, and water availability. Hence, there is large continental-scale variation in the species composition of early successional forests, which is mainly associated with biogeographic and environmental factors but not with human disturbance indicators. This floristic distinctiveness is partially driven by regionally restricted species belonging to widespread genera. Early secondary forests contribute therefore to restoring and conserving the distinctiveness of bioregions across the Neotropical realm, and forest restoration initiatives should use local species to assure that these distinct floras are maintained
Multidimensional tropical forest recovery
International audienceTropical forests disappear rapidly because of deforestation, yet they have the potential to regrow naturally on abandoned lands. We analyze how 12 forest attributes recover during secondary succession and how their recovery is interrelated using 77 sites across the tropics. Tropical forests are highly resilient to low-intensity land use; after 20 years, forest attributes attain 78% (33 to 100%) of their old-growth values. Recovery to 90% of old-growth values is fastest for soil (12 decades). Network analysis shows three independent clusters of attribute recovery, related to structure, species diversity, and species composition. Secondary forests should be embraced as a low-cost, natural solution for ecosystem restoration, climate change mitigation, and biodiversity conservation
Recommended from our members
Biodiversity recovery of Neotropical secondary forests.
Old-growth tropical forests harbor an immense diversity of tree species but are rapidly being cleared, while secondary forests that regrow on abandoned agricultural lands increase in extent. We assess how tree species richness and composition recover during secondary succession across gradients in environmental conditions and anthropogenic disturbance in an unprecedented multisite analysis for the Neotropics. Secondary forests recover remarkably fast in species richness but slowly in species composition. Secondary forests take a median time of five decades to recover the species richness of old-growth forest (80% recovery after 20 years) based on rarefaction analysis. Full recovery of species composition takes centuries (only 34% recovery after 20 years). A dual strategy that maintains both old-growth forests and species-rich secondary forests is therefore crucial for biodiversity conservation in human-modified tropical landscapes
Data from: Legume Abundance Along Successional And Rainfall Gradients In Neotropical Forests
This database is the product of the 2ndFOR collaborative research network on secondary forests.
The database contains total basal area data (in m2 ha-1) of legume trees (Leguminosae) for 1207 secondary forest plots differing in time since abandonment. The plots belong to different chonosequence studies. For a description of the database, see Gei et al. 2018. Legume Abundance Along Successional And Rainfall Gradients In Neotropical Forests. Nature Ecology and Evolution. The file "Legume basal area 2ndFOR data.csv" contains the following variables:
Chronosequence: name of the chronosequence site
Age: age of the plot (in years), "OG" indicates old-growth forest of unknown age
LBA: total basal area of legume trees (Leguminosae) of the plot in m2 ha-1
Reference: a citation for the chronosequence study, if available
PI/contact person: name(s) of the principal investigator(s) or contact person(s) for the chronosequence study
Data from: Legume abundance along successional and rainfall gradients in neotropical forests
The nutrient demands of regrowing tropical forests are partly satisfied by nitrogen (N)-fixing legume trees, but our understanding of the abundance of those species is biased towards wet tropical regions. Here we show how the abundance of Leguminosae is affected by both recovery from disturbance and large-scale rainfall gradients through a synthesis of forest-inventory plots from a network of 42 Neotropical forest chronosequences. During the first three decades of natural forest regeneration, legume basal area is twice as high in dry compared to wet secondary forests. The tremendous ecological success of legumes in recently disturbed, water-limited forests is likely related to both their reduced leaflet size and ability to fix N2, which together enhance legume drought tolerance and water-use efficiency. Earth system models should incorporate these large-scale successional and climatic patterns of legume dominance to provide more accurate estimates of the maximum potential for natural N fixation across tropical forests