18 research outputs found

    S100A7, a Novel Alzheimer's Disease Biomarker with Non-Amyloidogenic α-Secretase Activity Acts via Selective Promotion of ADAM-10

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    Alzheimer's disease (AD) is the most common cause of dementia among older people. At present, there is no cure for the disease and as of now there are no early diagnostic tests for AD. There is an urgency to develop a novel promising biomarker for early diagnosis of AD. Using surface-enhanced laser desorption ionization-mass spectrometry SELDI-(MS) proteomic technology, we identified and purified a novel 11.7-kDa metal- binding protein biomarker whose content is increased in the cerebrospinal fluid (CSF) and in the brain of AD dementia subjects as a function of clinical dementia. Following purification and protein-sequence analysis, we identified and classified this biomarker as S100A7, a protein known to be involved in immune responses. Using an adenoviral-S100A7 expression system, we continued to examine the potential role of S100A7 in AD amyloid neuropathology in in vitro model of AD. We found that the expression of exogenous S100A7 in primary cortico-hippocampal neuron cultures derived from Tg2576 transgenic embryos inhibits the generation of β-amyloid (Aβ)1–42 and Aβ1–40 peptides, coincidental with a selective promotion of “non- amyloidogenic” α-secretase activity via promotion of ADAM (a disintegrin and metalloproteinase)-10. Finally, a selective expression of human S100A7 in the brain of transgenic mice results in significant promotion of α-secretase activity. Our study for the first time suggests that S100A7 may be a novel biomarker of AD dementia and supports the hypothesis that promotion of S100A7 expression in the brain may selectively promote α-secretase activity in the brain of AD precluding the generation of amyloidogenic peptides. If in the future we find that S1000A7 protein content in CSF is sensitive to drug intervention experimentally and eventually in the clinical setting, S100A7 might be developed as novel surrogate index (biomarker) of therapeutic efficacy in the characterization of novel drug agents for the treatment of AD

    Functional analysis of liverworts in dual symbiosis with Glomeromycota and Mucoromycotina fungi under a simulated Palaeozoic CO2 decline.

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    Most land plants form mutualistic associations with arbuscular mycorrhizal fungi of the Glomeromycota, but recent studies have found that ancient plant lineages form mutualisms with Mucoromycotina fungi. Simultaneous associations with both fungal lineages have now been found in some plants, necessitating studies to understand the functional and evolutionary significance of these tripartite associations for the first time. We investigate the physiology and cytology of dual fungal symbioses in the early-diverging liverworts Allisonia and Neohodgsonia at modern and Palaeozoic-like elevated atmospheric CO2 concentrations under which they are thought to have evolved. We found enhanced carbon cost to liverworts with simultaneous Mucoromycotina and Glomeromycota associations, greater nutrient gain compared with those symbiotic with only one fungal group in previous experiments and contrasting responses to atmospheric CO2 among liverwort-fungal symbioses. In liverwort-Mucoromycotina symbioses, there is increased P-for-C and N-for-C exchange efficiency at 440 p.p.m. compared with 1500 p.p.m. CO2. In liverwort-Glomeromycota symbioses, P-for-C exchange is lower at ambient CO2 compared with elevated CO2. No characteristic cytologies of dual symbiosis were identified. We provide evidence of a distinct physiological niche for plant symbioses with Mucoromycotina fungi, giving novel insight into why dual symbioses with Mucoromycotina and Glomeromycota fungi persist to the present day.The ISME Journal advance online publication, 27 November 2015; doi:10.1038/ismej.2015.204

    Evaluation of Physical and Chemical Changes in Pharmaceuticals Flown on Space Missions

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    Efficacy and safety of medications used for the treatment of astronauts in space may be compromised by altered stability in space. We compared physical and chemical changes with time in 35 formulations contained in identical pharmaceutical kits stowed on the International Space Station (ISS) and on Earth. Active pharmaceutical content (API) was determined by ultra- and high-performance liquid chromatography after returning to Earth. After stowage for 28 months in space, six medications aboard the ISS and two of matching ground controls exhibited changes in physical variables; nine medications from the ISS and 17 from the ground met the United States Pharmacopeia (USP) acceptance criteria for API content after 28 months of storage. A higher percentage of medications from each flight kit had lower API content than the respective ground controls. The number of medications failing API requirement increased as a function of time in space, independent of expiration date. The rate of degradation was faster in space than on the ground for many of the medications, and most solid dosage forms met USP standard for dissolution after storage in space. Cumulative radiation dose was higher and increased with time in space, whereas temperature and humidity remained similar to those on the ground. Exposure to the chronic low dose of ionizing radiation aboard the spacecraft as well as repackaging of solid dosage forms in flight-specific dispensers may adversely affect stability of pharmaceuticals. Characterization of degradation profiles of unstable formulations and identification of chemical attributes of stability in space analog environments on Earth will facilitate development of space-hardy medications

    Training, development and learning

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    This chapter discusses and explores a number of critical issues related to training, development and learning (TDL). It does this by highlighting the differ­ences between the terms, reflecting on older, more classical approaches to training versus more contemporary and recent trends that are more situation­ or context-specific. Such context-specificity means that the older approaches to training, although useful, have to be rethought. More recent trends in global organizations such as technological advances, human expectations of what constitutes a valuable job, organizational expectations related to capabilities that match strategic business needs, and increased social interaction, have meant that the older approaches are now less valuable

    Xenopus laevis as a Bioindicator of Endocrine Disruptors in the Region of Central Chile

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