570 research outputs found

    Uterine environment and conceptus development in ruminants

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    Abstract Interferon tau (IFNT), the pregnancy recognition signal from trophectoderm cells of ruminant conceptuses abrogates the uterine luteolytic mechanism to ensure maintenance of functional corpora lutea for production of progesterone (P4). IFNT acts in concert with P4 to induce expression of genes for transport and/or secretion of histotroph that includes nutrients such as glucose and arginine that activate the mechanistic target of rapamycin (MTOR) nutrient sensing cell signaling pathway to stimulate proliferation, migration, differentiation and translation of mRNAs essential for growth and development of the conceptus. Arginine, leucine, glutamine and glucose increase in the uterine lumen during the peri-implantation period of pregnancy due to increased expression of their transporters by uterine luminal epithelium (LE) and superficial glandular epithelium (sGE) in response to P4 and IFNT. In day 16 ovine conceptus explant cultures, arginine increases GTP cyclohydrolase 1 mRNA, and IFNT, while arginine and glucose increase ornithine decarboxylase, nitric oxide synthase 2, and GCH1. Arginine can be metabolized to nitric oxide (NO) and polyamines which stimulate proliferation of ovine trophectoderm (oTr) cells. Secreted phosphoprotein 1 (SPP1, also known as osteopontin) in uterine histotroph increases focal adhesion assembly as a prerequisite for adhesion and migration of oTr cells through activation and cross-talk between MTOR, MAPK, and myosin II motor pathways. Glucose, arginine, leucine and glutamine stimulate MTOR signaling, proliferation and mRNA translation by oTr cells. Further, glucose and fructose were equivalent in stimulating proliferation and synthesis of hyaluronic acid via the hexosamine pathway in oTr and pig Tr cells. These mechanisms allow select nutrients and SPP1 to act coordinately to affect synthesis of proteins involved in cell signaling affecting conceptus growth, development, and survival during the peri-implantation period of pregnancy

    The influence of methylphenidate on the power spectrum of ADHD children – an MEG study

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    BACKGROUND: The present study was dedicated to investigate the influence of Methylphenidate (MPH) on cortical processing of children who were diagnosed with different subtypes of Attention Deficit Hyperactivity Disorder (ADHD). As all of the previous studies investigating power differences in different frequency bands have been using EEG, mostly with a relatively small number of electrodes our aim was to obtain new aspects using high density magnetoencephalography (MEG). METHODS: 35 children (6 female, 29 male) participated in this study. Mean age was 11.7 years (± 1.92 years). 17 children were diagnosed of having an Attention-Deficit/Hyperactivity Disorder of the combined type (ADHDcom, DSM IV code 314.01); the other 18 were diagnosed for ADHD of the predominantly inattentive type (ADHDin, DSM IV code 314.0). We measured the MEG during a 5 minute resting period with a 148-channel magnetometer system (MAGNES™ 2500 WH, 4D Neuroimaging, San Diego, USA). Power values were averaged for 5 bands: Delta (D, 1.5–3.5 Hz), Theta (T, 3.5–7.5 Hz), Alpha (A, 7.5–12.5 Hz), Beta (B, 12.5–25 Hz) and Global (GL, 1.5–25 Hz).). Additionally, attention was measured behaviourally using the D2 test of attention with and without medication. RESULTS: The global power of the frequency band from 1.5 to 25 Hz increased with MPH. Relative Theta was found to be higher in the left hemisphere after administration of MPH than before. A positive correlation was found between D2 test improvement and MPH-induced power changes in the Theta band over the left frontal region. A linear regression was computed and confirmed that the larger the improvement in D2 test performance, the larger the increase in Theta after MPH application. CONCLUSION: Main effects induced by medication were found in frontal regions. Theta band activity increased over the left hemisphere after MPH application. This finding contradicts EEG results of several groups who found lower levels of Theta power after MPH application. As relative Theta correlates with D2 test improvement we conclude that MEG provide complementary and therefore important new insights to ADHD

    Opinion: Why Protect Nature? Rethinking Values and the Environment

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    A cornerstone of environmental policy is the debate over protecting nature for humans’ sake (instrumental values) or for nature’s (intrinsic values) (1). We propose that focusing only on instrumental or intrinsic values may fail to resonate with views on personal and collective well-being, or “what is right,” with regard to nature and the environment. Without complementary attention to other ways that value is expressed and realized by people, such a focus may inadvertently promote worldviews at odds with fair and desirable futures. It is time to engage seriously with a third class of values, one with diverse roots and current expressions: relational values. By doing so, we reframe the discussion about environmental protection, and open the door to new, potentially more productive policy approaches

    Trust in Nanotechnology? On Trust as Analytical Tool in Social Research on Emerging Technologies

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    Trust has become an important aspect of evaluating the relationship between lay public and technology implementation. Experiences have shown that a focus on trust provides a richer understanding of reasons for backlashes of technology in society than a mere focus of public understanding of risks and science communication. Therefore, trust is also widely used as a key concept for understanding and predicting trust or distrust in emerging technologies. But whereas trust broadens the scope for understanding established technologies with well-defined questions and controversies, it easily fails to do so with emerging technologies, where there are no shared questions, a lack of public familiarity with the technology in question, and a restricted understanding amongst social researchers as to where distrust is likely to arise and how and under which form the technology will actually be implemented. Rather contrary, ‘trust’ might sometimes even direct social research into fixed structures that makes it even more difficult for social research to provide socially robust knowledge. This article therefore suggests that if trust is to maintain its important role in evaluating emerging technologies, the approach has to be widened and initially focus not on people’s motivations for trust, but rather the object of trust it self, as to predicting how and where distrust might appear, how the object is established as an object of trust, and how it is established in relation with the public

    Biomarkers of vitamin B-12 status in NHANES: a roundtable summary123456

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    A roundtable to discuss the measurement of vitamin B-12 (cobalamin) status biomarkers in NHANES took place in July 2010. NHANES stopped measuring vitamin B-12–related biomarkers after 2006. The roundtable reviewed 3 biomarkers of vitamin B-12 status used in past NHANES—serum vitamin B-12, methylmalonic acid (MMA), and total homocysteine (tHcy)—and discussed the potential utility of measuring holotranscobalamin (holoTC) for future NHANES. The roundtable focused on public health considerations and the quality of the measurement procedures and reference methods and materials that past NHANES used or that are available for future NHANES. Roundtable members supported reinstating vitamin B-12 status measures in NHANES. They noted evolving concerns and uncertainties regarding whether subclinical (mild, asymptomatic) vitamin B-12 deficiency is a public health concern. They identified the need for evidence from clinical trials to address causal relations between subclinical vitamin B-12 deficiency and adverse health outcomes as well as appropriate cutoffs for interpreting vitamin B-12–related biomarkers. They agreed that problems with sensitivity and specificity of individual biomarkers underscore the need for including at least one biomarker of circulating vitamin B-12 (serum vitamin B-12 or holoTC) and one functional biomarker (MMA or tHcy) in NHANES. The inclusion of both serum vitamin B-12 and plasma MMA, which have been associated with cognitive dysfunction and anemia in NHANES and in other population-based studies, was preferable to provide continuity with past NHANES. Reliable measurement procedures are available, and National Institute of Standards and Technology reference materials are available or in development for serum vitamin B-12 and MMA

    The associations between serum brain-derived neurotrophic factor, potential confounders, and cognitive decline: A longitudinal study

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    Brain-derived neurotrophic factor (BDNF) plays a role in the maintenance and function of neurons. Although persons with Alzheimer's disease have lower cortical levels of BDNF, evidence regarding the association between circulating BDNF and cognitive function is conflicting. We sought to determine the correlates of BDNF level and whether BDNF level was prospectively associated with cognitive decline in healthy older adults. We measured serum BDNF near baseline in 912 individuals. Cognitive status was assessed repeatedly with the modified Mini-Mental Status Examination and the Digit Symbol Substitution test over the next 10 years. We evaluated the association between BDNF and cognitive decline with longitudinal models. We also assessed the association between BDNF level and demographics, comorbidities and health behaviors. We found an association between serum BDNF and several characteristics that are also associated with dementia (race and depression), suggesting that future studies should control for these potential confounders. We did not find evidence of a longitudinal association between serum BDNF and subsequent cognitive test trajectories in older adults, although we did identify a potential trend toward a cross-sectional association. Our results suggest that serum BDNF may have limited utility as a biomarker of prospective cognitive decline

    Making sense of policy choices: understanding the roles of value predispositions, mass media, and cognitive processing in public attitudes toward nanotechnology

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    Using a nationally representative telephone survey of 1,015 adults in the United States, this study examines how value predispositions, communication variables, and perceptions of risks and benefits are associated with public support for federal funding of nanotechnology. Our findings show that highly religious individuals were less supportive of funding of nanotech than less religious individuals, whereas individuals who held a high deference for scientific authority were more supportive of funding of the emerging technology than those low in deference. Mass media use and elaborative processing of scientific news were positively associated with public support for funding, whereas factual scientific knowledge had no significant association with policy choices. The findings suggest that thinking about and reflecting upon scientific news promote better understanding of the scientific world and may provide a more sophisticated cognitive structure for the public to form opinions about nanotech than factual scientific knowledge. Finally, heuristic cues including trust in scientists and perceived risks and benefits of nanotech were found to be associated with public support for nanotech funding. We conclude with policy implications that will be useful for policymakers and science communication practitioners
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