113 research outputs found

    Ancient mitochondrial DNA provides high-resolution time scale of the peopling of the Americas

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    The exact timing, route, and process of the initial peopling of the Americas remains uncertain despite much research. Archaeological evidence indicates the presence of humans as far as southern Chile by 14.6 thousand years ago (ka), shortly after the Pleistocene ice sheets blocking access from eastern Beringia began to retreat. Genetic estimates of the timing and route of entry have been constrained by the lack of suitable calibration points and low genetic diversity of Native Americans. We sequenced 92 whole mitochondrial genomes from pre-Columbian South American skeletons dating from 8.6 to 0.5 ka, allowing a detailed, temporally calibrated reconstruction of the peopling of the Americas in a Bayesian coalescent analysis. The data suggest that a small population entered the Americas via a coastal route around 16.0 ka, following previous isolation in eastern Beringia for ~2.4 to 9 thousand years after separation from eastern Siberian populations. Following a rapid movement throughout the Americas, limited gene flow in South America resulted in a marked phylogeographic structure of populations, which persisted through time. All of the ancient mitochondrial lineages detected in this study were absent from modern data sets, suggesting a high extinction rate. To investigate this further, we applied a novel principal components multiple logistic regression test to Bayesian serial coalescent simulations. The analysis supported a scenario in which European colonization caused a substantial loss of pre-Columbian lineages.Bastien Llamas, Lars Fehren-Schmitz, Guido Valverde, Julien Soubrier, Swapan Mallick, Nadin Rohland, Susanne Nordenfelt, Cristina Valdiosera, Stephen M. Richards, Adam Rohrlach, Maria Inés Barreto Romero, Isabel Flores Espinoza, Elsa Tomasto Cagigao, Lucía Watson Jiménez, Krzysztof Makowski, Ilán Santiago Leboreiro Reyna, Josefina Mansilla Lory, Julio Alejandro Ballivián Torrez, Mario A. Rivera, Richard L. Burger, Maria Constanza Ceruti, Johan Reinhard, R. Spencer Wells, Gustavo Politis, Calogero M. Santoro, Vivien G. Standen, Colin Smith, David Reich, Simon Y. W. Ho, Alan Cooper and Wolfgang Haa

    The meaning of actualization of self-care resources among a group of older home-dwelling people—A hermeneutic study

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    Self-care is an activity of mature persons who have developed their abilities to take care of themselves. Individuals can choose to actualize their self-care abilities into self-care activities to maintain, restore, or improve health and well-being. It is of importance to understand the meaning of the actualization of self-care resources among older people. The aim of this study was to investigate the meaning of the actualization of self-care resources, i.e., actions taken to improve, maintain, or restore health and well-being, among a group of older home-dwelling individuals with a high sense of coherence. The design of this study was to reanalyse narratives revealing self-care activities from 11 (five females and six males) Norwegian older home-dwelling people (65 years or older) identified as having a high sense of coherence. In order to reveal the meaning and get an understanding of why these self-care resources were realized or actualized, a Gadamerian-based research method was chosen. The analysis revealed four themes that showed the meaning of actualization of self-care resources in the study group: “Desire to carry on”, “Be of use to others”, “Self-realization”, and “Confidence to manage in the future”. The findings showed what older people found meaningful to strive for, and this information can be used as a guide for health professionals when supporting older people in their self-care. Older people with self-care resources can also be an important resource for others in need of social contact and practical help. These resources have to be asked for in voluntary work among older people in need of help and, thereby, can be a valuable supplement to the community health care system

    Depression and Motivation

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    Among the characteristic features of depression is a diminishment in or lack of action and motivation. In this paper, I consider a dominant philosophical account which purports to explain this lack of action or motivation. This approach comes in different versions but a common theme is, I argue, an over reliance on psychologistic assumptions about action–explanation and the nature of motivation. As a corrective I consider an alternative view that gives a prominent place to the body in motivation. Central to the experience of depression are changes to how a person is motivated to act and, also as central, are changes to bodily feelings and capacities. I argue that broadly characterizing motivation in terms of bodily capacities can, in particular, provide a more compelling account of depressive motivational pathology

    What to think of canine obesity? Emerging challenges to our understanding of human-animal health relationships.

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    The coincident and increasing occurrence of weight-related health problems in humans and canines in Western societies poses a challenge to our understanding of human–animal health relationships. More specifically, the epistemological and normative impetus provided by current approaches to shared health risks and chronic diseases in cohabiting human and animal populations does not account for causal continuities in the way that people and their pets live together. An examination of differences in medical responses to these conditions in human and pet dogs points to the existence of a distinct conceptual and ethical sphere for companion animal veterinary medicine. The disengagement of veterinary medicine for companion animals from human medicine has implications for our understanding what is required for health and disease prevention at the level of populations. This disengagement of companion animal veterinarians from family and preventive medicine, in particular, constrains professional roles, planning processes and, thereby, the potential for better-integrated responses to shared burdens of chronic conditions that increasingly affect the health and welfare of people and companion animals. Keywords: Human–Animal Relationships, Medical Epistemology, Companion Animal Welfare, Veterinary Ethics, Public Health Ethics, One HealthCanadian Institutes of Health Research, Open Operating Gran

    Assessing people with dementia participating in cognitive stimulation activities – A qualitative pilot video analysis exploring the importance of facilitating the participation

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    BACKGROUND: This pilot video analysis was part of a feasibility control study, which aimed to gain information about the size and variability of the changes in outcome measures to plan a substantive effect study. It compared a cognitive stimulation programme named Lifelong Learning with other existing dementia services. OBJECTIVE: The pilot video analysis explored how facilitation is performed, when assessing people with dementia with standardized measures, to ensure their participation in research. DESIGN: A test battery of five measures (Mini-Mental State Examination (MMSE), Quality of Life in Alzheimer's Disease Scale (QoL-AD), General Self-Efficacy Scale, Rosenberg Self-Esteem Scale and Hawthorn Friendship Scale) was used. Each assessment was video-recorded. The findings from a microanalysis of 10 videos are presented in this article. SETTING: The study involved 55 active participants with mild-to-moderate dementia in six municipalities in Northern Denmark. RESULTS: The identified themes related to supportive facilitation: Positive facilitator strategies; Creating a safe and comfortable environment; and to dilemmas in facilitation: Balancing multiple dilemmas and Balancing the MMSE test. DISCUSSION: Results are discussed in relation to using standardized measures. CONCLUSION: The quality of facilitation when using standardized measures is of great importance as it may influence the participant, the assessment and the answers given. The facilitation role needs to be thoroughly planned and executed with ethical consideration to improve the participation of vulnerable groups in research and ensure a person-centred approach. PATIENT OR PUBLIC CONTRIBUTION: The identified measures were chosen based upon previous qualitative results and user-involvement workshops with people with dementia

    Comparison of serum hepatitis B virus replication markers in patients with chronic hepatitis B: studies on HBeAg/Anti-HBe system, viral dna polymerase and HBV-DNA

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    The detection of HBV-DNA in serum by molecular hybridization is the most sensitive and specific marker of replication and infectivity of hepatitis B virus and currently is proposed as a routine diagnostic technique in the follow-up of HBV - related diseases. Comparing different techniques already described, we found that direct spotting of serum samples on nitrocellulose membranes under vacuum filtration, followed by denaturing and neutralizing washes is more practical, simple, sensible and reproducible. DNA polymerase assay using phosphonoformic acid as specific viral inhibitor has shown 86.8% of concordance with HBV-DNA detection, and so, it is an useful alternative in the follow-up of hepatitis B chronic patients. We found 19.2% HBeAg positive samples with no other markers of viral replication and no anti-HBe positive sample had detectable HBV-DNA. Discordance between the 2 systems have been extensively described, and we confirm this for the first time in our country. Molecular biological techniques are essential to determine the replication status of chronic hepatitis B patients.A detecção do genoma do HBV no soro por hibridização molecular é o mais sensível e específico marcador da replicação e infectividade do HBV, sendo sua utilização proposta como técnica rotineira no acompanhamento de doenças relacionadas a este vírus. Comparando diferentes técnicas descritas anteriormente, escolhemos a deposição direta das amostras séricas sobre a membrana de nitrocelulose sob filtração a vácuo, seguida de banhos desnaturantes e neutralisantes como mais prática e simples, com sensibilidade equivalente. O ensaio da DNA polimerase usando ácido fosfonofórmico como inibidor virai específico mostrou 86.8% de concordância com a detecção direta do DNA viral, sendo, portanto, uma alternativa viável no acompanhamento de pacientes com hepatite crônica B. Encontramos 19,2% das amostras AgHBe positivos sem outros marcadores de replicação viral. Por outro lado, nenhuma amostra anti-HBe positiva teve HBV-DNA detectável. Discordância entre estes dois sistemas foi extensamente descrita, e confirmamos pela primeira vez este fato em pacientes com hepatite crônica B em nosso país. Técnicas de biologia molecular são, portanto, fundamentais na determinação da replicação viral em cada paciente

    Phagocytosis Escape by a Staphylococcus aureus Protein That Connects Complement and Coagulation Proteins at the Bacterial Surface

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    Upon contact with human plasma, bacteria are rapidly recognized by the complement system that labels their surface for uptake and clearance by phagocytic cells. Staphylococcus aureus secretes the 16 kD Extracellular fibrinogen binding protein (Efb) that binds two different plasma proteins using separate domains: the Efb N-terminus binds to fibrinogen, while the C-terminus binds complement C3. In this study, we show that Efb blocks phagocytosis of S. aureus by human neutrophils. In vitro, we demonstrate that Efb blocks phagocytosis in plasma and in human whole blood. Using a mouse peritonitis model we show that Efb effectively blocks phagocytosis in vivo, either as a purified protein or when produced endogenously by S. aureus. Mutational analysis revealed that Efb requires both its fibrinogen and complement binding residues for phagocytic escape. Using confocal and transmission electron microscopy we show that Efb attracts fibrinogen to the surface of complement-labeled S. aureus generating a ‘capsule’-like shield. This thick layer of fibrinogen shields both surface-bound C3b and antibodies from recognition by phagocytic receptors. This information is critical for future vaccination attempts, since opsonizing antibodies may not function in the presence of Efb. Altogether we discover that Efb from S. aureus uniquely escapes phagocytosis by forming a bridge between a complement and coagulation protein
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