3,844 research outputs found
Bridging Cultures through Unpaid Labor: US Volunteer Teachers’ Experiences in China’s Yunnan Province
International volunteering has become a complex field in the context of globalization. Within the discourses of international volunteering and development programs as well as in the voices of volunteers, the field can be understood as one of unpaid transnational labor, as social activism and altruism, and as a new “soft power” post-colonial agenda. Many studies contend in this context that international volunteers need better training for intercultural understanding amidst these disparate frameworks, to make meaning out of their service and effectively contribute to communities they serve. This study examines the motivations, experiences, and challenges of US volunteer teachers in China’s Yunnan Province as reported within a survey implemented in 2012. Findings elaborate on the challenge volunteers face reconciling cross-cultural views of education while working in post-colonial global contexts, and suggest that intercultural training is necessary to prepare volunteers for related global work practices in the future.postprin
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Diverse specificities, phenotypes, and antiviral activities of cytomegalovirus-specific CD8+ T cells.
UNLABELLED: CD8(+) T cells specific for pp65, IE1, and IE2 are present at high frequencies in human cytomegalovirus (HCMV)-seropositive individuals, and these have been shown to have phenotypes associated with terminal differentiation, as well as both cytokine and proliferative dysfunctions, especially in the elderly. However, more recently, T cell responses to many other HCMV proteins have been described, but little is known about their phenotypes and functions. Consequently, in this study, we chose to determine the diversity of HCMV-specific CD8(+) T cell responses to the products of 11 HCMV open reading frames (ORFs) in a cohort of donors aged 20 to 80 years old as well as the ability of the T cells to secrete gamma interferon (IFN-γ). Finally, we also tested their functional antiviral capacity using a novel viral dissemination assay. We identified substantial CD8(+) T cell responses by IFN-γ enzyme-linked immunospot (ELISPOT) assays to all 11 of these HCMV proteins, and across the cohort, individuals displayed a range of responses, from tightly focused to highly diverse, which were stable over time. CD8(+) T cell responses to the HCMV ORFs were highly differentiated and predominantly CD45RA(+), CD57(+), and CD28(-), across the cohort. These highly differentiated cells had the ability to inhibit viral spread even following direct ex vivo isolation. Taken together, our data argue that HCMV-specific CD8(+) T cells have effective antiviral activity irrespective of the viral protein recognized across the whole cohort and despite viral immune evasion. IMPORTANCE: Human cytomegalovirus (HCMV) is normally carried without clinical symptoms and is widely prevalent in the population; however, it often causes severe clinical disease in individuals with compromised immune responses. HCMV is never cleared after primary infection but persists in the host for life. In HCMV carriers, the immune response to HCMV includes large numbers of virus-specific immune cells, and the virus has evolved many mechanisms to evade the immune response. While this immune response seems to protect healthy people from subsequent disease, the virus is never eliminated. It has been suggested that this continuous surveillance by the immune system may have deleterious effects in later life. The study presented in this paper examined immune responses from a cohort of donors and shows that these immune cells are effective at controlling the virus and can overcome the virus' lytic cycle immune evasion mechanisms.This work was funded by British Medical Research Council Grant G0701279 and supported by the NIHR Cambridge BRC Cell Phenotyping hub.This is the accepted manuscript version. The final published version is available from ASM at http://jvi.asm.org/content/early/2014/07/03/JVI.01477-14.abstract
Repeatability of quantitative18F-FLT uptake measurements in solid tumors: an individual patient data multi-center meta-analysis
INTRODUCTION: 3'-deoxy-3'-[18F]fluorothymidine (18F-FLT) positron emission tomography (PET) provides a non-invasive method to assess cellular proliferation and response to antitumor therapy. Quantitative18F-FLT uptake metrics are being used for evaluation of proliferative response in investigational setting, however multi-center repeatability needs to be established. The aim of this study was to determine the repeatability of18F-FLT tumor uptake metrics by re-analyzing individual patient data from previously published reports using the same tumor segmentation method and repeatability metrics across cohorts. METHODS: A systematic search in PubMed, EMBASE.com and the Cochrane Library from inception-October 2016 yielded five18F-FLT repeatability cohorts in solid tumors.18F-FLT avid lesions were delineated using a 50% isocontour adapted for local background on test and retest scans. SUVmax, SUVmean, SUVpeak, proliferative volume and total lesion uptake (TLU) were calculated. Repeatability was assessed using the repeatability coefficient (RC = 1.96 × SD of test-retest differences), linear regression analysis, and the intra-class correlation coefficient (ICC). The impact of different lesion selection criteria was also evaluated. RESULTS: Images from four cohorts containing 30 patients with 52 lesions were obtained and analyzed (ten in breast cancer, nine in head and neck squamous cell carcinoma, and 33 in non-small cell lung cancer patients). A good correlation was found between test-retest data for all18F-FLT uptake metrics (R2 ≥ 0.93; ICC ≥ 0.96). Best repeatability was found for SUVpeak(RC: 23.1%), without significant differences in RC between different SUV metrics. Repeatability of proliferative volume (RC: 36.0%) and TLU (RC: 36.4%) was worse than SUV. Lesion selection methods based on SUVmax ≥ 4.0 improved the repeatability of volumetric metrics (RC: 26-28%), but did not affect the repeatability of SUV metrics. CONCLUSIONS: In multi-center studies, differences ≥ 25% in18F-FLT SUV metrics likely represent a true change in tumor uptake. Larger differences are required for FLT metrics comprising volume estimates when no lesion selection criteria are applied
The expression and regulation of enzymes mediating the biosynthesis of triglycerides and phospholipids in keratinocytes/epidermis
Triglycerides and phospholipids play an important role in epidermal permability barrier formation and function. They are synthesized de novo in the epidermis via the glycerol-3-phosphate pathway, catalyzed sequentially by a group of enzymes that have multiple isoforms including glycerol-3-phosphate acyltransferase (GPAT), 1-acylglycerol-3-phosphate acyltransferase (AGPAT), Lipin and diacylglycerol acyltransferase (DGAT). Here we review the current knowledge of GPAT, AGPAT, Lipin and DGAT enzymes in keratinocytes/epidermis focusing on the expression levels of the various isoforms and their localization in mouse epidermis. Additionally, the factors regulating their gene expression, including calcium induced differentiation, PPAR and LXR activators, and the effect of acute permeability barrier disruption will be discussed
Concurrent adaptation to opposing visual displacements during an alternating movement.
It has been suggested that, during tasks in which subjects are exposed to a visual rotation of cursor feedback, alternating bimanual adaptation to opposing rotations is as rapid as unimanual adaptation to a single rotation (Bock et al. in Exp Brain Res 162:513–519, 2005). However, that experiment did not test strict alternation of the limbs but short alternate blocks of trials. We have therefore tested adaptation under alternate left/right hand movement with opposing rotations. It was clear that the left and right hand, within the alternating conditions, learnt to adapt to the opposing displacements at a similar rate suggesting that two adaptive states were formed concurrently. We suggest that the separate limbs are used as contextual cues to switch between the relevant adaptive states. However, we found that during online correction the alternating conditions had a significantly slower rate of adaptation in comparison to the unimanual conditions. Control conditions indicate that the results are not directly due the alternation between limbs or to the constant switching of vision between the two eyes. The negative interference may originate from the requirement to dissociate the visual information of these two alternating displacements to allow online control of the two arms
Seizure pathways change on circadian and slower timescales in individual patients with focal epilepsy.
Personalized medicine requires that treatments adapt to not only the patient but also changing factors within each individual. Although epilepsy is a dynamic disorder characterized by pathological fluctuations in brain state, surprisingly little is known about whether and how seizures vary in the same patient. We quantitatively compared within-patient seizure network evolutions using intracranial electroencephalographic (iEEG) recordings of over 500 seizures from 31 patients with focal epilepsy (mean 16.5 seizures per patient). In all patients, we found variability in seizure paths through the space of possible network dynamics. Seizures with similar pathways tended to occur closer together in time, and a simple model suggested that seizure pathways change on circadian and/or slower timescales in the majority of patients. These temporal relationships occurred independent of whether the patient underwent antiepileptic medication reduction. Our results suggest that various modulatory processes, operating at different timescales, shape within-patient seizure evolutions, leading to variable seizure pathways that may require tailored treatment approaches
Development of Climate Smart Agriculture and Climate Information System Relevant Curricula for Staff, Students and other stakeholders in Universities in Africa
The Accelerating Impacts of CGIAR Climate Research for Africa project (AICCRA), working through CCAFS, intends to make CGIAR-led cutting-edge science practices/technologies/tools available throughout Africa; especially in Sub-regions extremely vulnerable to climate change. The Regional Universities Forum for Capacity Building in Agriculture (RUFORUM), a network of 150 universities in 38 countries spanning the whole African continent is a partner in the AICCRA project. RUFORUM’s contribution in the AICCRA project is focused on mobilising African universities, create awareness and enhance the use of Climate Smart Agriculture (CSA) and Climate information services (CIS) knowledge and products developed by the CGIAR Centres and other research institutions engaged in CSA and CIS. Enhancing the use of CSA and CIS involves capacity, knowledge and technology audits at national and institutional level, mobilise CGIAR and other research centres to provide CSA and CIS knowledge,
technology and skills and training of faculty to deploy the CSA and CIS products in training, research and outreach. Knowledge transfer and capacity-building activities therefore form the central part of RUFORUM’s participation in the AICCRA project
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HCMV Specific CD4+ T Cells are poly-functional and can respond to HCMV Infected Dendritic Cells in vitro.
Human cytomegalovirus (HCMV) infection and periodic re-activation is generally well controlled by the HCMV-specific T cell response in healthy people. While the CD8+ T cell response to HCMV has been extensively studied, the HCMV-specific CD4+ T cell effector response is not as well understood, especially in the context of direct interactions with HCMV infected cells. We screened the IFNγ and IL-10 response to 6 HCMV peptide pools (selected as the most frequently responded to in our previous studies: pp65, pp71, IE1, IE2, gB and US3) in 84 donors, aged 23 - 74 years. Predominantly the HCMV specific CD4+ T cell response to pp65, IE1, IE2 and gB was Th1 biased with neither loss nor accumulation of these responses with increasing age. A larger proportion of donors produced an IL-10 response to pp71 and US3 but the IFNγ response was still dominant. CD4+ T cells specific to the HCMV proteins studied were predominantly effector memory cells and produced both cytotoxic (CD107a expression) and cytokine (MIP1β secretion) effector responses. Importantly, when we measured the CD4+ T cell response to CMV infected Dendritic Cells in vitro, we observed that the CD4+ T cells produced a range of cytotoxic and secretory effector functions, despite the presence of CMV encoded immune evasion molecules. CD4+ T cell responses to HCMV infected dendritic cells were sufficient to control the dissemination of virus in an in vitro assay. Together the results show that HCMV-specific CD4+ T cell responses are highly functional even from elderly individuals and are directly anti-viral.
IMPORTANCE: Human cytomegalovirus (HCMV) infection is carried for a lifetime and in healthy people is kept under control by the immune system. HCMV has evolved many mechanisms to evade the immune response, possibly explaining why the virus is never eliminated during the hosts' lifetime. Dysfunction of immune cells associated with long-term carriage of HCMV has been linked with poor responses to new pathogens and vaccines when older. In this study we have investigated the response of a subset of immune cells (CD4+ T cell) to HCMV proteins in healthy donors of all ages demonstrating that the functionality of the CD4+ T cells is maintained. We have also shown that CD4+ T cells produce effector functions in response to HCMV infected cells and can prevent virus spread. Our work demonstrates that these HCMV-specific immune cells retain many important functions and help to prevent deleterious HCMV disease in healthy older people.We thank the National Institute for Health Research (NIHR) Cambridge Biomedical Research Centre (BRC) and NHS Blood and Transplant (NHSBT) for funding. Further information can be found at www.cambridgebioresource.org.uk. This research was supported by the Cambridge NIHR BRC Cell Phenotyping Hub
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