145 research outputs found

    Stepwise Differentiation of Retinal Ganglion Cells from Human Pluripotent Stem Cells Enables Analysis of Glaucomatous Neurodegeneration

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    Human pluripotent stem cells (hPSCs), including both embryonic and induced pluripotent stem cells, possess the unique ability to readily differentiate into any cell type of the body, including cells of the retina. Although previous studies have demonstrated the ability to differentiate hPSCs to a retinal lineage, the ability to derive retinal ganglion cells (RGCs) from hPSCs has been complicated by the lack of specific markers with which to identify these cells from a pluripotent source. In the current study, the definitive identification of hPSC-derived RGCs was accomplished by their directed, stepwise differentiation through an enriched retinal progenitor intermediary, with resultant RGCs expressing a full complement of associated features and proper functional characteristics. These results served as the basis for the establishment of induced pluripotent stem cells (iPSCs) from a patient with a genetically inherited form of glaucoma, which results in damage and loss of RGCs. Patient-derived RGCs specifically exhibited a dramatic increase in apoptosis, similar to the targeted loss of RGCs in glaucoma, which was significantly rescued by the addition of candidate neuroprotective factors. Thus, the current study serves to establish a method by which to definitively acquire and identify RGCs from hPSCs and demonstrates the ability of hPSCs to serve as an effective in vitro model of disease progression. Moreover, iPSC-derived RGCs can be utilized for future drug screening approaches to identify targets for the treatment of glaucoma and other optic neuropathies

    Florbetapir positron emission tomography and cerebrospinal fluid biomarkers

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    BACKGROUND: We evaluated the relationship between florbetapir-F18 positron emission tomography (FBP PET) and cerebrospinal fluid (CSF) biomarkers. METHODS: Alzheimer's Disease Neuroimaging Initiative-Grand Opportunity and Alzheimer's Disease Neuroimaging Initiative 2 (GO/2) healthy control (HC), mild cognitive impairment (MCI), and Alzheimer's disease (AD) dementia subjects with clinical measures and CSF collected ±90 days of FBP PET data were analyzed using correlation and logistic regression. RESULTS: In HC and MCI subjects, FBP PET anterior and posterior cingulate and composite standard uptake value ratios correlated with CSF amyloid beta (AÎČ1-42) and tau/AÎČ1-42 ratios. Using logistic regression, AÎČ1-42, total tau (t-tau), phosphorylated tau181P (p-tau), and FBP PET composite each differentiated HC versus AD. AÎČ1-42 and t-tau distinguished MCI versus AD, without additional contribution by FBP PET. Total tau and p-tau added discriminative power to FBP PET when classifying HC versus AD. CONCLUSION: Based on cross-sectional diagnostic groups, both amyloid and tau measures distinguish healthy from demented subjects. Longitudinal analyses are needed

    Florbetapir F18 PET Amyloid Neuroimaging and Characteristics in Patients With Mild and Moderate Alzheimer Dementia

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    Background Clinical diagnosis of Alzheimer disease (AD) is challenging, with a 70.9%–87.3% sensitivity and 44.3%–70.8% specificity, compared with autopsy diagnosis. Florbetapir F18 positron emission tomography (FBP-PET) estimates beta-amyloid plaque density antemortem. Methods Of 2052 patients (≄55 years old) clinically diagnosed with mild or moderate AD dementia from 2 solanezumab clinical trials, 390 opted to participate in a FBP-PET study addendum. We analyzed baseline prerandomization characteristics. Results A total of 22.4% had negative FBP-PET scans, whereas 72.5% of mild and 86.9% of moderate AD patients had positive results. No baseline clinical variable reliably differentiated negative from positive FBP-PET scan groups. Conclusions These data confirm the challenges of correctly diagnosing AD without using biomarkers. FBP-PET can aid AD dementia differential diagnosis by detecting amyloid pathology antemortem, even when the diagnosis of AD is made by expert clinicians

    Framing REDD+ in the Brazilian national media: how discourses evolved amid global negotiation uncertainties

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    Reducing emissions from deforestation and degradation (REDD+) in tropical countries is an important and contested element of the post-Kyoto climate regime. For policy options which generate controversy between diverse actor groups, such as REDD+, mass media plays an important role in defining and supporting policy possibilities. Analysis of the way in which national media frames issues of climate change and deforestation can offer insights into the nature of the contested domains of the REDD+ policy process. Here, we examine the Brazilian national media discourses surrounding REDD+ because it contributes to setting the tone of policy debates at the federal level. Specifically, we ask the following: (i) How was REDD+ portrayed in the Brazilian national print media and whose opinions and perceptions were represented? and (ii) How have media frames on REDD+ in the national print media changed over time? Our results contribute with new knowledge for understanding the observed progress of REDD+ in Brazil. We identify two main themes that dominate the focus in the national media coverage of REDD+, specifically “politics and policymaking” (representing half the coverage) and “economics and market” (with over a third). Results show that discussions around carbon markets were amongst the most contested and that optimism in relation to REDD+ effectiveness declined over time. The analysis suggests that positions adopted on the national REDD+ strategy were shaped by state and federal collision of interests. We demonstrate an evolution of national concerns from an initial focus on efficiency (e.g. finance and carbon markets) to a recentred focus on equity issues (e.g. implementation of safeguards). We conclude with some thoughts on the implications of these features for REDD+ interventions and implementation in Brazil

    Climate Obstruction in the Global South: Future Research Trajectories

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    open access article“Climate Obstruction” broadly refers to campaigns and other policy actions led by well-organized and financed networks of corporate and other actors who have actively sought to prevent global and/or national action on climate change over the past four decades. In turn, these campaigns often shape public debates, which can affect political support and collective mobilization to mitigate climate change. However, to date, most of the research on climate obstruction has focused on countries in the Global North, especially the United States. Given considerable gaps in research and knowledge, this opinion paper presents a future research agenda needs to shine greater light on if and in what form climate obstruction in the Global South appears

    Professionalism, Golf Coaching and a Master of Science Degree: A commentary

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    As a point of reference I congratulate Simon Jenkins on tackling the issue of professionalism in coaching. As he points out coaching is not a profession, but this does not mean that coaching would not benefit from going through a professionalization process. As things stand I find that the stimulus article unpacks some critically important issues of professionalism, broadly within the context of golf coaching. However, I am not sure enough is made of understanding what professional (golf) coaching actually is nor how the development of a professional golf coach can be facilitated by a Master of Science Degree (M.Sc.). I will focus my commentary on these two issues

    Governing the Global Land Grab: Multipolarity, Ideas and Complexity in Transnational Governance

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    Since 2008, a series of new regulatory initiatives have emerged to address large-scale land grabs. These initiatives are occurring simultaneously at multiple levels of social organization instead of a single, overarching institutional site. A significant portion of this activity is taking place at the transnational level. We suggest that transnational land governance is indicative of emerging shifts in the practice of governance of global affairs. We analyze such shifts by asking two related questions: what does land grabbing tell us about developments in transnational governance, particularly with regard to North-South relations, and what do these developments in transnational governance mean for regulating land grabbing?Desde 2008, ha surgido una serie de nuevas iniciativas regulatorias para tratar acaparamientos de tierra a gran escala. Estas iniciativas están sucediendo simultáneamente a niveles múltiples de la organización social en vez de un lugar institucional predominante. Una porción importante de esta actividad está tomando lugar al nivel transnacional. Sugerimos que la gobernanza de tierras trasnacionales es indicativa de los cambios que están surgiendo en la práctica de gobernanza de los asuntos globales. Analizamos tales cambios haciendo dos preguntas relacionadas: ¿qué nos dice el acaparamiento de tierras sobre los desarrollos en la gobernanza trasnacional, particularmente con las relaciones norte-sur?, y ¿qué significan estos desarrollos en gobernanza trasnacional para regular el acaparamiento de tierras
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