1,121 research outputs found

    Prevention of bone mineral changes induced by bed rest: Modification by static compression simulating weight bearing, combined supplementation of oral calcium and phosphate, calcitonin injections, oscillating compression, the oral diophosphonatedisodium etidronate, and lower body negative pressure

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    The phenomenon of calcium loss during bed rest was found to be analogous to the loss of bone material which occurs in the hypogravic environment of space flight. Ways of preventing this occurrence are investigated. A group of healthy adult males underwent 24-30 weeks of continuous bed rest. Some of them were given an exercise program designed to resemble normal ambulatory activity; another subgroup was fed supplemental potassium phosphate. The results from a 12-week period of treatment were compared with those untreated bed rest periods. The potassium phosphate supplements prevented the hypercalciuria of bed rest, but fecal calcium tended to increase. The exercise program did not diminish the negative calcium balance. Neither treatment affected the heavy loss of mineral from the calcaneus. Several additional studies are developed to examine the problem further

    Core Circadian Clock Genes Regulate Leukemia Stem Cells in AML

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    Leukemia stem cells (LSCs) have the capacity to self-renew and propagate disease upon serial transplantation in animal models, and elimination of this cell population is required for curative therapies. Here, we describe a series of pooled, in vivo RNAi screens to identify essential transcription factors (TFs) in a murine model of acute myeloid leukemia (AML) with genetically and phenotypically defined LSCs. These screens reveal the heterodimeric, circadian rhythm TFs Clock and Bmal1 as genes required for the growth of AML cells in vitro and in vivo. Disruption of canonical circadian pathway components produces anti-leukemic effects, including impaired proliferation, enhanced myeloid differentiation, and depletion of LSCs. We find that both normal and malignant hematopoietic cells harbor an intact clock with robust circadian oscillations, and genetic knockout models reveal a leukemia-specific dependence on the pathway. Our findings establish a role for the core circadian clock genes in AML.National Institutes of Health (U.S.) (Grant P01 CA066996)National Institutes of Health (U.S.) (Grant R01 HL082945)National Cancer Institute (U.S.) (Grant P30-CA14051

    Rationale, design and methods for process evaluation in the HEALTHY study

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    The HEALTHY study was a multi-site randomized trial designed to determine whether a 3-year school-based intervention targeting nutrition and physical activity behaviors could effectively reduce risk factors associated with type 2 diabetes in middle school children. Pilot and formative studies were conducted to inform the development of the intervention components and the process evaluation methods for the main trial. During the main trial, both qualitative and quantitative assessments monitored the fidelity of the intervention and motivated modifications to improve intervention delivery. Structured observations of physical education classes, total school food environments, classroom-based educational modules, and communications and promotional campaigns provided verification that the intervention was delivered as intended. Interviews and focus groups yielded a multidimensional assessment of how the intervention was delivered and received, as well as identifying the barriers to and facilitators of the intervention across and within participating schools. Interim summaries of process evaluation data were presented to the study group as a means of ensuring standardization and quality of the intervention across the seven participating centers. Process evaluation methods and procedures documented the fidelity with which the HEALTHY study was implemented across 21 intervention schools and identified ways in which the intervention delivery might be enhanced throughout the study

    Management of upper airway edema caused by hereditary angioedema

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    Hereditary angioedema is a rare disorder with a genetic background involving mutations in the genes encoding C1-INH and of factor XII. Its etiology is unknown in a proportion of cases. Recurrent edema formation may involve the subcutis and the submucosa - the latter can produce obstruction in the upper airways and thereby lead to life-threatening asphyxia. This is the reason for the high, 30-to 50-per-cent mortality of undiagnosed or improperly managed cases. Airway obstruction can be prevented through early diagnosis, meaningful patient information, timely recognition of initial symptoms, state-of-the-art emergency therapy, and close monitoring of the patient. Prophylaxis can substantially mitigate the risk of upper airway edema and also improve the patients' quality of life. Notwithstanding the foregoing, any form of upper airway edema should be regarded as a potentially life-threatening condition. None of the currently available prophylactic modalities is capable of preventing UAE with absolute certainty

    Who is accessing public-sector anti-retroviral treatment in the Free State, South Africa? An exploratory study of the first three years of programme implementation

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    <p>Abstract</p> <p>Background</p> <p>Although South Africa has the largest public-sector anti-retroviral treatment (ART) programme in the world, anti-retroviral coverage in adults was only 40.2% in 2008. However, longitudinal studies of who is accessing the South African public-sector ART programme are scarce. This study therefore had one main research question: who is accessing public-sector ART in the Free State Province, South Africa? The study aimed to extend the current literature by investigating, in a quantitative manner and using a longitudinal study design, the participants enrolled in the public-sector ART programme in the period 2004-2006 in the Free State Province of South Africa.</p> <p>Methods</p> <p>Differences in the demographic (age, sex, population group and marital status) socio-economic (education, income, neo-material indicators), geographic (travel costs, relocation for ART), and medical characteristics (CD4, viral load, time since first diagnosis, treatment status) among 912 patients enrolled in the Free State public-sector ART programme between 2004 and 2006 were assessed with one-way analysis of variance, Bonferroni post-hoc analysis, and cross tabulations with the chi square test.</p> <p>Results</p> <p>The patients accessing treatment tended to be female (71.1%) and unemployed (83.4%). However, although relatively poor, those most likely to access ART services were not the most impoverished patients. The proportion of female patients increased (<it>P </it>< 0.05) and their socio-economic situation improved between 2004 and 2006 (<it>P </it>< 0.05). The increasing mean transport cost (<it>P </it>< 0.05) to visit the facility is worrying, because this cost is an important barrier to ART uptake and adherence. Encouragingly, the study results revealed that the interval between the first HIV-positive diagnosis and ART initiation decreased steadily over time (<it>P </it>< 0.05). This was also reflected in the increasing baseline CD4 cell count at ART initiation (<it>P </it>< 0.05).</p> <p>Conclusions</p> <p>Our analysis showed significant changes in the demographic, socio-economic, geographic, and medical characteristics of the patients during the first three years of the programme. Knowledge of the characteristics of these patients can assist policy makers in developing measures to retain them in care. The information reported here can also be usefully applied to target patient groups that are currently not reached in the implementation of the ART programme.</p

    Measurement of the Bottom-Strange Meson Mixing Phase in the Full CDF Data Set

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    We report a measurement of the bottom-strange meson mixing phase \beta_s using the time evolution of B0_s -> J/\psi (->\mu+\mu-) \phi (-> K+ K-) decays in which the quark-flavor content of the bottom-strange meson is identified at production. This measurement uses the full data set of proton-antiproton collisions at sqrt(s)= 1.96 TeV collected by the Collider Detector experiment at the Fermilab Tevatron, corresponding to 9.6 fb-1 of integrated luminosity. We report confidence regions in the two-dimensional space of \beta_s and the B0_s decay-width difference \Delta\Gamma_s, and measure \beta_s in [-\pi/2, -1.51] U [-0.06, 0.30] U [1.26, \pi/2] at the 68% confidence level, in agreement with the standard model expectation. Assuming the standard model value of \beta_s, we also determine \Delta\Gamma_s = 0.068 +- 0.026 (stat) +- 0.009 (syst) ps-1 and the mean B0_s lifetime, \tau_s = 1.528 +- 0.019 (stat) +- 0.009 (syst) ps, which are consistent and competitive with determinations by other experiments.Comment: 8 pages, 2 figures, Phys. Rev. Lett 109, 171802 (2012

    The unexpected resurgence of Weyl geometry in late 20-th century physics

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    Weyl's original scale geometry of 1918 ("purely infinitesimal geometry") was withdrawn by its author from physical theorizing in the early 1920s. It had a comeback in the last third of the 20th century in different contexts: scalar tensor theories of gravity, foundations of gravity, foundations of quantum mechanics, elementary particle physics, and cosmology. It seems that Weyl geometry continues to offer an open research potential for the foundations of physics even after the turn to the new millennium.Comment: Completely rewritten conference paper 'Beyond Einstein', Mainz Sep 2008. Preprint ELHC (Epistemology of the LHC) 2017-02, 92 pages, 1 figur
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