576 research outputs found

    Gender Differences Among Veterans Deployed in Support of the Wars in Afghanistan and Iraq

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    BACKGROUND: The changing scope of women’s roles in combat operations has led to growing interest in women’s deployment experiences and post-deployment adjustment. OBJECTIVES: To quantify the gender-specific frequency of deployment stressors, including sexual and non-sexual harassment, lack of social support and combat exposure. To quantify gender-specific post-deployment mental health conditions and associations between deployment stressors and posttraumatic stress disorder (PTSD), to inform the care of Veterans returning from the current conflicts. DESIGN: National mail survey of OEF/OIF Veterans randomly sampled within gender, with women oversampled. SETTING: The community. PARTICIPANTS: In total, 1,207 female and 1,137 male Veterans from a roster of all Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF) Veterans. Response rate was 48.6 %. MAIN MEASURES: Deployment stressors (including combat and harassment stress), PTSD, depression, anxiety and alcohol use, all measured via self-report. KEY RESULTS: Women were more likely to report sexual harassment (OR = 8.7, 95% CI: 6.9, 11) but less likely to report combat (OR = 0 .62, 95 % CI: 0.50, 0.76). Women and men were equally likely to report symptoms consistent with probable PTSD (OR = 0 .87, 95 % CI: 0.70, 1.1) and symptomatic anxiety (OR  =  1.1, 9 5% CI: 0.86, 1.3). Women were more likely to report probable depression (OR = 1.3, 95 % CI: 1.1, 1.6) and less likely to report problematic alcohol use (OR  = 0 .59, 9 5% CI: 0.47, 0.72). With a five-point change in harassment stress, adjusted odds ratios for PTSD were 1.36 (95 % CI: 1.23, 1.52) for women and 1.38 (95 % CI: 1.19, 1.61) for men. The analogous associations between combat stress and PTSD were 1.31 (95 % CI: 1.24, 1.39) and 1.31 (95 % CI: 1.26, 1.36), respectively. CONCLUSIONS: Although there are important gender differences in deployment stressors—including women’s increased risk of interpersonal stressors—and post-deployment adjustment, there are also significant similarities. The post-deployment adjustment of our nation’s growing population of female Veterans seems comparable to that of our nation’s male Veterans

    Soil respiration in a northeastern US temperate forest: a 22‐year synthesis

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    To better understand how forest management, phenology, vegetation type, and actual and simulated climatic change affect seasonal and inter‐annual variations in soil respiration (Rs), we analyzed more than 100,000 individual measurements of soil respiration from 23 studies conducted over 22 years at the Harvard Forest in Petersham, Massachusetts, USA. We also used 24 site‐years of eddy‐covariance measurements from two Harvard Forest sites to examine the relationship between soil and ecosystem respiration (Re). Rs was highly variable at all spatial (respiration collar to forest stand) and temporal (minutes to years) scales of measurement. The response of Rs to experimental manipulations mimicking aspects of global change or aimed at partitioning Rs into component fluxes ranged from −70% to +52%. The response appears to arise from variations in substrate availability induced by changes in the size of soil C pools and of belowground C fluxes or in environmental conditions. In some cases (e.g., logging, warming), the effect of experimental manipulations on Rs was transient, but in other cases the time series were not long enough to rule out long‐term changes in respiration rates. Inter‐annual variations in weather and phenology induced variation among annual Rs estimates of a magnitude similar to that of other drivers of global change (i.e., invasive insects, forest management practices, N deposition). At both eddy‐covariance sites, aboveground respiration dominated Re early in the growing season, whereas belowground respiration dominated later. Unusual aboveground respiration patterns—high apparent rates of respiration during winter and very low rates in mid‐to‐late summer—at the Environmental Measurement Site suggest either bias in Rs and Re estimates caused by differences in the spatial scale of processes influencing fluxes, or that additional research on the hard‐to‐measure fluxes (e.g., wintertime Rs, unaccounted losses of CO2 from eddy covariance sites), daytime and nighttime canopy respiration and its impacts on estimates of Re, and independent measurements of flux partitioning (e.g., aboveground plant respiration, isotopic partitioning) may yield insight into the unusually high and low fluxes. Overall, however, this data‐rich analysis identifies important seasonal and experimental variations in Rs and Re and in the partitioning of Re above‐ vs. belowground

    Reconstruction of a human cornea by the self-assembly approach of tissue engineering using the three native cell types

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    Purpose: The purpose of this study was to produce and characterize human tissue-engineered corneas reconstructed using all three corneal cell types (epithelial, stromal, and endothelial cells) by the self-assembly approach. Methods: Fibroblasts cultured in medium containing serum and ascorbic acid secreted their own extracellular matrix and formed sheets that were superposed to reconstruct a stromal tissue. Endothelial and epithelial cells were seeded on each side of the reconstructed stroma. After culturing at the air-liquid interface, the engineered corneas were fixed for histology and transmission electron microscopy (TEM). Immunofluorescence labeling of epithelial keratins, basement membrane components, Na+/K+-ATPase α1, and collagen type I was also performed. Results: Epithelial and endothelial cells adhered to the reconstructed stroma. After 10 days at the air-liquid interface, the corneal epithelial cells stratified (4 to 5 cell layers) and differentiated into well defined basal and wing cells that also expressed Na+/K+-ATPase α1 protein, keratin 3/12, and basic keratins. Basal epithelial cells from the reconstructed epithelium formed many hemidesmosomes and secreted a well defined basement membrane rich in laminin V and collagen VII. Endothelial cells formed a monolayer of tightly-packed cells and also expressed the function related protein Na+/K +-ATPase α1. Conclusions: This study demonstrates the feasibility of producing a complete tissue-engineered human cornea, similar to native corneas, using untransformed fibroblasts, epithelial and endothelial cells, without the need for exogenous biomaterial

    Soil respiration in a northeastern US temperate forest: a 22‐year synthesis

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    To better understand how forest management, phenology, vegetation type, and actual and simulated climatic change affect seasonal and inter‐annual variations in soil respiration (Rs), we analyzed more than 100,000 individual measurements of soil respiration from 23 studies conducted over 22 years at the Harvard Forest in Petersham, Massachusetts, USA. We also used 24 site‐years of eddy‐covariance measurements from two Harvard Forest sites to examine the relationship between soil and ecosystem respiration (Re). Rs was highly variable at all spatial (respiration collar to forest stand) and temporal (minutes to years) scales of measurement. The response of Rs to experimental manipulations mimicking aspects of global change or aimed at partitioning Rs into component fluxes ranged from −70% to +52%. The response appears to arise from variations in substrate availability induced by changes in the size of soil C pools and of belowground C fluxes or in environmental conditions. In some cases (e.g., logging, warming), the effect of experimental manipulations on Rs was transient, but in other cases the time series were not long enough to rule out long‐term changes in respiration rates. Inter‐annual variations in weather and phenology induced variation among annual Rs estimates of a magnitude similar to that of other drivers of global change (i.e., invasive insects, forest management practices, N deposition). At both eddy‐covariance sites, aboveground respiration dominated Re early in the growing season, whereas belowground respiration dominated later. Unusual aboveground respiration patterns—high apparent rates of respiration during winter and very low rates in mid‐to‐late summer—at the Environmental Measurement Site suggest either bias in Rs and Re estimates caused by differences in the spatial scale of processes influencing fluxes, or that additional research on the hard‐to‐measure fluxes (e.g., wintertime Rs, unaccounted losses of CO2 from eddy covariance sites), daytime and nighttime canopy respiration and its impacts on estimates of Re, and independent measurements of flux partitioning (e.g., aboveground plant respiration, isotopic partitioning) may yield insight into the unusually high and low fluxes. Overall, however, this data‐rich analysis identifies important seasonal and experimental variations in Rs and Re and in the partitioning of Re above‐ vs. belowground

    Mapeamento digital de classes de solos: caracterĂ­sticas da abordagem brasileira.

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    O solo Ă© cada vez mais reconhecido como tendo um importante papel nos ecossistemas, assim como para a produção de alimentos e regulação do clima global. Por esse motivo, a demanda por informaçÔes relevantes e atualizadas em solos Ă© crescente. Pesquisadores em ciĂȘncia do solo estĂŁo sendo demandados a gerar informaçÔes em diferentes resoluçÔes espaciais e com qualidade associada dentro do que estĂĄ sendo chamado de Mapeamento Digital de Solos (MDS). Devido ao crescente nĂșmero de trabalhos relacionados ao MDS, faz-se necessĂĄrio reunir e discutir as principais caracterĂ­sticas dos estudos relacionados ao mapeamento digital de classes de solos no Brasil, o que irĂĄ possibilitar uma perspectiva mais ampla dos caminhos, alĂ©m de nortear trabalhos e demandas futuras. O mapeamento de classes de solos empregando tĂ©cnicas de MDS Ă© recente no paĂ­s, com a primeira publicação em 2006. Entre as funçÔes preditivas utilizadas, predomina o emprego da tĂ©cnica de regressĂ”es logĂ­sticas. O fator de formação relevo foi empregado na totalidade dos estudos revisados. Quanto Ă  avaliação da qualidade dos modelos preditivos, o emprego da matriz de erros e do Ă­ndice kappa tĂȘm sido os procedimentos mais usuais. A consolidação dessa abordagem automatizada como ferramenta auxiliar ao mapeamento convencional passa pelo treinamento dos jovens pedĂłlogos para a utilização de tecnologias da geoinformação e de ferramentas quantitativas dos aspectos de variabilidade do solo

    Optical pulse labeling studies reveal exogenous seeding slows α-synuclein clearance

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    The accumulation of α-synuclein (α-syn) in intracellular formations known as Lewy bodies (LBs) is associated with several neurodegenerative diseases including Parkinson's disease and Lewy Body Dementia. There is still limited understanding of how α-syn and LB formation is associated with cellular dysfunction and degeneration in these diseases. To examine the clearance and production dynamics of α-syn we transduced organotypic murine brain slice cultures (BSCs) with recombinant adeno-associated viruses (rAAVs) to express Dendra2-tagged human wild-type (WT) and mutant A53T α-syn, with and without the addition of exogenous α-syn fibrillar seeds and tracked them over several weeks in culture using optical pulse labeling. We found that neurons expressing WT or mutant A53T human α-syn show similar rates of α-syn turnover even when insoluble, phosphorylated Ser129 α-syn has accumulated. Taken together, this data reveals α-syn aggregation and overexpression, pSer129 α-syn, nor the A53T mutation affect α-syn dynamics in this system. Prion-type seeding with exogenous α-syn fibrils significantly slows α-syn turnover, in the absence of toxicity but is associated with the accumulation of anti-p62 immunoreactivity and Thiazin Red positivity. Prion-type induction of α-syn aggregation points towards a potential protein clearance deficit in the presence of fibrillar seeds and the ease of this system to explore precise mechanisms underlying these processes. This system facilitates the exploration of α-syn protein dynamics over long-term culture periods. This platform can further be exploited to provide mechanistic insight on what drives this slowing of α-syn turnover and how therapeutics, other genes or different α-syn mutations may affect α-syn protein dynamics

    The Role of Alpha-Synuclein Oligomerization and Aggregation in Cellular and Animal Models of Parkinson’s Disease

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    α-synuclein (α-syn) is a synaptic protein in which four mutations (A53T, A30P, E46K and gene triplication) have been found to cause an autosomal dominant form of Parkinson’s disease (PD). It is also the major component of intraneuronal protein aggregates, designated as Lewy bodies (LBs), a prominent pathological hallmark of PD. How α-syn contributes to LB formation and PD is still not well-understood. It has been proposed that aggregation of α-syn contributes to the formation of LBs, which then leads to neurodegeneration in PD. However, studies have also suggested that aggregates formation is a protective mechanism against more toxic α-syn oligomers. In this study, we have generated α-syn mutants that have increased propensity to form aggregates by attaching a CL1 peptide to the C-terminal of α-syn. Data from our cellular study suggest an inverse correlation between cell viability and the amount of α-syn aggregates formed in the cells. In addition, our animal model of PD indicates that attachment of CL1 to α-syn enhanced its toxicity to dopaminergic neurons in an age-dependent manner and induced the formation of Lewy body-like α-syn aggregates in the substantia nigra. These results provide new insights into how α-syn-induced toxicity is related to its aggregation

    Site-specific perturbations of alpha-synuclein fibril structure by the Parkinson's disease associated mutations A53T and E46K.

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    PMCID: PMC3591419This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Parkinson's disease (PD) is pathologically characterized by the presence of Lewy bodies (LBs) in dopaminergic neurons of the substantia nigra. These intracellular inclusions are largely composed of misfolded α-synuclein (AS), a neuronal protein that is abundant in the vertebrate brain. Point mutations in AS are associated with rare, early-onset forms of PD, although aggregation of the wild-type (WT) protein is observed in the more common sporadic forms of the disease. Here, we employed multidimensional solid-state NMR experiments to assess A53T and E46K mutant fibrils, in comparison to our recent description of WT AS fibrils. We made de novo chemical shift assignments for the mutants, and used these chemical shifts to empirically determine secondary structures. We observe significant perturbations in secondary structure throughout the fibril core for the E46K fibril, while the A53T fibril exhibits more localized perturbations near the mutation site. Overall, these results demonstrate that the secondary structure of A53T has some small differences from the WT and the secondary structure of E46K has significant differences, which may alter the overall structural arrangement of the fibrils
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