39 research outputs found

    Regulatory T Cell Expansion in HTLV-1 and Strongyloidiasis Co-infection Is Associated with Reduced IL-5 Responses to Strongyloides stercoralis Antigen

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    Human strongyloidiasis varies from a mild, controlled infection to a severe frequently fatal disseminated infection depending on the hosts. Patients infected with the retrovirus HTLV-1 have more frequent and more severe forms of strongyloidiasis. It is not clear how human strongyloidiasis is controlled by the immune system and how HTLV-1 infection affects this control. We hypothesize that HTLV-1 leads to dissemination of Strongyloides stercoralis by augmenting regulatory T cell numbers, which in turn down regulate the immune response to the parasite. In our study, patients with HTLV-1 and Strongyloides co-infection had higher parasite burdens than patients with only strongyloidiasis. Eosinophils play an essential role in control of strongyloidiasis in animal models, and eosinophil counts were decreased in the HTLV-1 and Strongyloides stercoralis co-infected subjects compared to patients with only strongyloidiasis. The proportion of T cells with a regulatory cell phenotype was increased in HTLV-1 positive subjects co-infected with strongyloidiasis compared to patients with only strongyloidiasis. IL-5 is a key host molecule in stimulating eosinophil production and activation, and Strongyloides stercoralis antigen-specific IL-5 responses were reduced in strongyloidiasis/HTLV-1 co-infected patients. Reduced IL-5 responses and eosinophil counts were inversely correlated to the number of regulatory T cells. These findings suggest a role for regulatory T cells in susceptibility to Strongyloides hyperinfection

    The reference frame for encoding and retention of motion depends on stimulus set size

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    YesThe goal of this study was to investigate the reference frames used in perceptual encoding and storage of visual motion information. In our experiments, observers viewed multiple moving objects and reported the direction of motion of a randomly selected item. Using a vector-decomposition technique, we computed performance during smooth pursuit with respect to a spatiotopic (nonretinotopic) and to a retinotopic component and compared them with performance during fixation, which served as the baseline. For the stimulus encoding stage, which precedes memory, we found that the reference frame depends on the stimulus set size. For a single moving target, the spatiotopic reference frame had the most significant contribution with some additional contribution from the retinotopic reference frame. When the number of items increased (Set Sizes 3 to 7), the spatiotopic reference frame was able to account for the performance. Finally, when the number of items became larger than 7, the distinction between reference frames vanished. We interpret this finding as a switch to a more abstract nonmetric encoding of motion direction. We found that the retinotopic reference frame was not used in memory. Taken together with other studies, our results suggest that, whereas a retinotopic reference frame may be employed for controlling eye movements, perception and memory use primarily nonretinotopic reference frames. Furthermore, the use of nonretinotopic reference frames appears to be capacity limited. In the case of complex stimuli, the visual system may use perceptual grouping in order to simplify the complexity of stimuli or resort to a nonmetric abstract coding of motion information

    Chapter 1. Bending the Curve: Ten Scalable Solutions for Carbon Neutrality and Climate Stability

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    We are living in a world of over seven billion people, with annual greenhouse gas emissions of approximately 50 billion tons a year and rising steadily. If continued unabated, the world is on target to warm by about 2 °C in less than 40 years, pushing the climate to a regime unlike any that has been witnessed in the last million years. Nonetheless, we still have time to avert such a catastrophic scenario, or delay its occurrence by several decades to provide human societies and the ecosystem with the time to adjust. In order to mitigate the possibility of climate disruption, we need to recognize that fossil fuel based technologies have become outdated and transform the energy system to that of low-carbon, sustainable and secure energy systems. In addition, we have to mitigate emissions of the four short-lived climate pollutants to bring immediate relief from climate change and protect vulnerable societies. Stability of the climate system involves not only the centrality of scientific and technological advancements and investments, but also necessary shifts in social structure and behavior by individuals, communities and societies worldwide as well as market based instruments, sub-national collaborations and governance structure. Fortunately, living laboratories—such as the State of California and the University of California system, which has pledged to become carbon neutral by 2025—provide demonstrable solutions which hold promise in alleviating the climate warming in the next generation. These jurisdictions are tiny emitters in the global picture, but they offer the potential for leverage through demonstrating (Figure 1) new technologies as well as workable institutions that cut emissions. We outline 10 pragmatic solutions—a “kit of parts” rooted in California but scalable to the world—that taken together, can “bend the curve” of the upward trajectory of human-caused warming trends. Wholesale transformation of our current fossil fuel based energy systems towards sustainable energy is among the greatest of societal challenges—and opportunities—faced in the 21st century
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