In lieu of an abstract, here is a brief excerpt of the content:Alzheimer's Disease, Mild Cognitive Impairment, and the Biology of Intrinsic AgingThomas B. L. Kirkwood (bio)Keywordsaging, Alzheimer’s disease, genetic mutation, mild cognitive impairment, telomereThe article by Gaines and Whitehouse (2006) raises key questions about the uncertain relationship between (i) the intrinsic, "normal" aging process, and (ii) the clinicopathologic states represented by the labels of Alzheimer's disease (AD) and mild cognitive impairment (MCI). This short commentary offers a perspective on this (...) debate that is drawn from a consideration of underlying biological mechanisms.Because age is unquestionably the greatest single risk factor associated with AD and MCI, I begin by asking what we know about the intrinsic processes of aging. The central feature of current understanding of intrinsic aging is that it consists of the gradual, lifelong accumulation of a wide variety of molecular and cellular faults that begins very early in life and eventually leads to overt functional impairments resulting in age-related frailty, disability, and disease (Kirkwood 2005). This is an essentially bottom-up process. A strong consensus has emerged in recent years that there is no active program for aging and that there are no genetic factors that have evolved specifically to cause aging or age-related diseases. Unquestionably, there are genes that influence susceptibility to disease and even length of life, but these genes are genes for maintenance and repair functions, not for aging. It is the limitation in the past evolutionary pressure to invest in greater longevity than was required, within an environment where life was usually truncated by hazards such as starvation, injury, or infection, that means that our maintenance systems—good as they are—are insufficient to keep us going indefinitely. Added to this is the idea that there are probably also genes that program processes that are good for the young organism, but which may in later life have harmful effects. Processes like inflammation and apoptosis, which are seen to occur extensively in aged tissues, including brain, surely evolved to help cope with infection and cellular damage arising earlier in life. That they are called into play in aged tissues is a direct, but secondary, consequence of accumulated damage.With this general framework to understand the intrinsic biology of aging, let us now ask what we might expect a priori for the aging of an organ such [End Page 79] as the brain. Although we cannot pretend complete ignorance of how the brain actually does age, our enquiry can be based entirely on data from other organ systems, so we can develop our predictions about brain aging without prejudice.Aging begins very early during human development, faults accumulating from the first stages of embryonic development. Each time a cell divides, each of the daughter cells is likely to acquire a few new mutations. We know this from the estimates for the error rate in DNA replication and the size of the human genome. It is confirmed by direct evidence that at individual gene loci where mutations have been measured, mutation frequency increases with age (Morley 1998; Vijg 2000). In addition to replication errors, DNA is damaged on a daily basis to a very considerable degree by agents such as reactive oxygen species (free radicals), which are formed as byproducts of normal cellular metabolism. Although most of this damage is corrected by repair, the repair mechanisms themselves are not error free and additional mutations accumulate through this route. If a mutation is lethal to the cell, the cell dies and thus the mutation is eliminated. However, the majority of mutations are nonlethal, either because the mutation is recessive and the cell carries an intact gene copy on the other chromosome, because the gene is not currently required, or because the mutation produces only a delayed deleterious effect. Examples of genes that produce delayed deleterious effects include the genes responsible for familial AD. It is interesting to reflect that on statistical grounds alone, it is almost certain that each of us carries a randomly determined fraction of cells in our brains that bear amyloid precursor protein or presenilin mutations associated with AD. We also carry a heterogeneous array of random mutations that compromise essential cell maintenance functions. How many such... (shrink)

Cyclin-dependent kinase 5 has been implicated in Alzheimer's disease pathogenesis. Here, we demonstrate that overexpression of p25, an activator of cdk5, led to increased levels of BACE1 mRNA and protein in vitro and in vivo. A p25/cdk5 responsive region containing multiple sites for signal transducer and activator of transcription was identified in the BACE1 promoter. STAT3 interacts with the BACE1 promoter, and p25-overexpressing mice had elevated levels of pSTAT3 and BACE1, whereas cdk5-deficient mice had reduced levels. Furthermore, mice with a (...) targeted mutation in the STAT3 cdk5 responsive site had lower levels of BACE1. Increased BACE levels in p25 overexpressing mice correlated with enhanced amyloidogenic processing that could be reversed by a cdk5 inhibitor. These data demonstrate a pathway by which p25/cdk5 increases the amyloidogenic processing of APP through STAT3-mediated transcriptional control of BACE1 that could have implications for AD pathogenesis. (shrink)

Early versions of satellite and radiosonde datasets suggested that the tropical surface had warmed more than the troposphere, while climate models consistently showed tropospheric amplification of surface warming in response to human-caused increases in greenhouse gases. We revisit such comparisons here using new observational estimates of surface and tropospheric temperature changes. We find that there is no longer a serious discrepancy between modeled and observed trends in the tropics. Our results contradict a recent claim that all simulated temperature trends in (...) the tropical troposphere are inconsistent with observations. This claim was based on the use of older radiosonde and satellite datasets and on two methodological errors: the neglect of observational trend uncertainties introduced by interannual climate variability and application of an inappropriate statistical “consistency test”.This emerging reconciliation of models and observations has two primary explanations. First, because of changes in the treatment of buoy and satellite information, new surface temperature datasets yield slightly reduced tropical warming relative to earlier versions. Second, recently developed satellite and radiosonde datasets now show larger warming of the tropical lower troposphere. In the case of a new satellite dataset from remote sensing systems, enhancedRSS warming is due to an improved procedure of adjusting for inter-satellite biases. When the RSS-derived tropospheric temperature trend is compared with four different observed estimates of surface temperature change, the surface warming is invariably amplified in the tropical troposphere, consistent with model results. Even if we use data from a second satellite dataset with smaller tropospheric warming than in remote sensing systems RSS, observed tropical lapse rates are not significantly different from those in all model simulations.Our results contradict a recent claim that all simulated temperature trends in the tropical troposphere and in tropical lapse rates are inconsistent with observations. This claim was based on the use of older radiosonde and satellite datasets and on two methodological errors: the neglect of observational trend uncertainties introduced by interannual climate variability and application of an inappropriate statistical “consistency test”. (shrink)

While outcomes for children with T-cell acute lymphoblastic leukemia have improved dramatically, survival rates for patients with relapsed/refractory disease remain dismal. Prior studies indicate that glucocorticoid resistance is more common than resistance to other chemotherapies at relapse. In addition, failure to clear peripheral blasts during a prednisone prophase correlates with an elevated risk of relapse in newly diagnosed patients. Here we show that intrinsic GC resistance is present at diagnosis in early thymic precursor T-ALLs as well as in a subset (...) of non-ETP T-ALLs. GC-resistant non-ETP T-ALLs are characterized by strong induction of JAK/STAT signaling in response to interleukin-7 stimulation. Removing IL7 or inhibiting JAK/STAT signaling sensitizes these T-ALLs, and a subset of ETP T-ALLs, to GCs. The combination of the GC dexamethasone and the JAK1/2 inhibitor ruxolitinib altered the balance between pro- and anti-apoptotic factors in samples with IL7-dependent GC resistance, but not in samples with IL7-independent GC resistance. Together, these data suggest that the addition of ruxolitinib or other inhibitors of IL7 receptor/JAK/STAT signaling may enhance the efficacy of GCs in a biologically defined subset of T-ALL.Leukemia advance online publication, 30 May 2017; doi:10.1038/leu.2017.136. (shrink)

Using covariant derivatives and the operator definitions of quantum mechanics, gauge invariant Proca and Lehnert equations are derived and the Lorenz condition is eliminated in U(1) invariant electrodynamics. It is shown that the structure of the gauge invariant Lehnert equation is the same in an O(3) invariant theory of electrodynamics.

The article comparatively analyzes A.C. Danto’s and P. Ricœur’s theories of historical narration. Ricœur’s synthetic assimilation of Danto’s views is interpreted as a characteristic phenomenon of the dialogue between hermeneutics and analytical philosophy, and in a broader perspective – of contemporary European continental and Anglo-American philosophical traditions. The version of the analytical philosophy of history developed by Danto is interpreted as being formed in the course of overcoming epistemological program of logical positivism under the impact of a platform of linguistic (...) philosophy, pragmatism and neo-pragmatism as well as F. Nietzsche’s perspectivism and the ideas of existentialism. The articles examines fundamental conclusions of Danto’s “descriptive metaphysics” of history, which influence his understanding of a number of epistemological factors and ontological assumptions specific for the theory of historical narration. At the late stage of the evolution of his philosophy of history, Danto spoke of a radical challenge to his views on the part of T. Kuhn’s theory, but he did not give to it a constructive answer. Despite the significant philosophical differences, a number of Danto’s historical narration theory’s theses became acceptable for Ricœur, especially in the light of the American colleague final confession that knowledge of the past is dependent on the kind of existential presence in history specific for a human being. Taking M. Heidegger’s and H.G. Gadamer’s ideas as a basis of his approach to narration problem, Ricœur considered also important the “linguistic turn” initiated by L. Wittgenstein. Offering a positive evaluation of Danto’s analysis of history language, Ricœur simultaneously rightly criticized him for his neglect of the formal instruments of organizing of narrative – plot, intrigue, and composition that should affect the knowledge resources and testify on the unity of narration features in history and fiction as well. (shrink)

This paper describes the Electronic Schoolbag, a digital workspace developed at the University of Savoie (France) and analyses its usages. This online environment is dedicated to the educational world: it offers pupils, students, teachers, school staff, or parents, personal and group workspaces in which individual or collaborative activities can take place. The flexibility of this software, allowing synchronous or asynchronous activities, lies in the “participation model”. This model allows groups themselves to describe and organise their activities. The architecture that permits (...) its implementation in the Electronic Schoolbag workspace is described. The study of the practices of the workspace is then presented. This requires different observation methods, according to the different procedures chosen: real practices provided by quantitative methods (analysis of the logs of the actions and questionnaires) and imagined practices provided by qualitative methods (semi-directive interviews). The results obtained from the university users allow us to assess the evolution of the usages for different periods and on different university sites. The observatory also lets us list the main uses of the Electronic Schoolbag for educative communication (collaborative vs. individual, informative vs. communicative). (shrink)

Next SectionObjective The purpose of this article is to investigate the need for ethics support in Dutch healthcare institutions in order to understand why ethics support is often not used in practice and which factors are relevant in this context. Methods This study had a mixed methods design integrating quantitative and qualitative research methods. Two survey questionnaires, two focus groups and 17 interviews were conducted among board members and ethics support staff in Dutch healthcare institutions. Findings Most respondents see a (...) need for ethics support. This need is related to the complexity of contemporary healthcare, the contribution of ethics support to the core business of the organisation and to the surplus value of paying structural attention to ethical issues. The need for ethics support is, however, not unconditional. Reasons for a lacking need include: aversion of innovations, negative associations with the notion of ethics support service, and organisational factors like resources and setting. Conclusion There is a conditioned need for ethics support in Dutch healthcare institutions. The promotion of ethics support in healthcare can be fostered by focusing on formats which fit the needs of (practitioners in) healthcare institutions. The emphasis should be on creating a (culture of) dialogue about the complex situations which emerge daily in contemporary healthcare practice. (shrink)

Background Residual dried blood spots (rDBS) from newborn screening programmes represent a valuable resource for medical research, from basic sciences, through clinical to public health. In Hong Kong, there is no legislation for biobanking. Parents’ view on the retention and use of residual newborn blood samples could be cultural-specific and is important to consider for biobanking of rDBS. Objective To study the views and concerns on long-term storage and secondary use of rDBS from newborn screening programmes among Hong Kong Chinese (...) parents. Methods A mixed-method approach was used to study the views and concerns on long-term storage and secondary use of rDBS from newborn screening programmes among Hong Kong Chinese parents of children 0–3 years or expecting parents through focus groups (8 groups; 33 participants) and a survey (n = 1012, 85% mothers) designed with insights obtained from the focus groups. We used framework analysis to summarise the themes as supportive factors, concerns and critical arguments for retention and secondary use of rDBS from focus group discussion. We used multiple logistic regression to assess factors associated with support for retention and secondary use of rDBS in the survey. Results Both in focus groups and survey, majority of parents were not aware of the potential secondary use of rDBS. Overall secondary use of rDBS in medical research was well accepted by a large proportion of Hong Kong parents, even if all potential future research could not be specified in a broad consent. However parents were concerned about potential risks of biobanking rDBS including leaking of data and mis-use of genetic information. Parents wanted to be asked for permission before rDBS are stored and mainly did not accept an “opt-out” approach. The survey showed that parents born in mainland China, compared to Hong Kong born parents, had lower awareness of newborn screening but higher support in biobanking rDBS. Higher education was associated with support in rDBS biobanking only among fathers. Conclusion Long-term storage and secondary use of rDBS from newborn screening for biomedical research and a broad consent for biobanking of rDBS are generally acceptable to Hong Kong parents given their autonomy is respected and their privacy is protected, highlighting the importance of an accountable governance and a transparent access policy for rDBS biobanks. (shrink)