171 research outputs found

    Making the Most of Mealtimes (M3): protocol of a multi-centre cross-sectional study of food intake and its determinants in older adults living in long term care homes

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    Background: Older adults living in long term care (LTC) homes are nutritionally vulnerable, often consuming insufficient energy, macro-and micronutrients to sustain their health and function. Multiple factors are proposed to influence food intake, yet our understanding of these diverse factors and their interactions are limited. The purpose of this paper is to fully describe the protocol used to examine determinants of food and fluid intake among older adults participating in the Making the Most of Mealtimes (M3) study. Methods: A conceptual framework that considers multi-level influences on mealtime experience, meal quality and meal access was used to design this multi-site cross-sectional study. Data were collected from 639 participants residing in 32 LTC homes in four Canadian provinces by trained researchers. Food intake was assessed with three-days of weighed food intake (main plate items), as well as estimations of side dishes, beverages and snacks and compared to the Dietary Reference Intake. Resident-level measures included: nutritional status, nutritional risk; disease conditions, medication, and diet prescriptions; oral health exam, signs of swallowing difficulty and olfactory ability; observed eating behaviours, type and number of staff assisting with eating; and food and foodservice satisfaction. Function, cognition, depression and pain were assessed using interRAI LTCF with selected items completed by researchers with care staff. Care staff completed a standardized person-directed care questionnaire. Researchers assessed dining rooms for physical and psychosocial aspects that could influence food intake. Management from each site completed a questionnaire that described the home, menu development, food production, out-sourcing of food, staffing levels, and staff training. Hierarchical regression models, accounting for clustering within province, home and dining room will be used to determine factors independently associated with energy and protein intake, as proxies for intake. Proportions of residents at risk of inadequate diets will also be determined. Discussion: This rigorous and comprehensive data collection in a large and diverse sample will provide, for the first time, the opportunity to consider important modifiable factors associated with poor food intake of residents in LTC. Identification of factors that are independently associated with food intake will help to develop effective interventions that support food intake.Canadian Institutes of Health Research (CIHR) , The PI is an endowed research chair with the Schlegel-University of Waterloo Research Institute for Aging; half of her salary is provided by this non-profit organizatio

    Alterations in glutamatergic signaling contribute to the decline of circadian photoentrainment in aged mice

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    Robust physiological circadian rhythms form an integral part of well-being. The aging process has been found to negatively impact systems that drive circadian physiology, typically manifesting as symptoms associated with abnormal/disrupted sleeping patterns. Here, we investigated the age-related decline in light-driven circadian entrainment in male C57BL/6J mice. We compared light-driven resetting of circadian behavioral activity in young (1e2 months) and old (14e18 months) mice and explored alterations in the glutamatergic pathway at the level of the circadian pacemaker, the suprachiasmatic nucleus (SCN). Aged animals showed a significant reduction in sensitivity to behavioral phase resetting by light. We show that this change was through alterations in N-Methyl-D-aspartate (NMDA) signaling at the SCN, where NMDA, a glutamatergic agonist, was less potent in inducing clock resetting. Finally, we show that this shift in NMDA sensitivity was through the reduced SCN expression of this receptor’s NR2B subunit. Only in young animals did an NR2B antagonist attenuate behavioral resetting. These results can help target treatments that aim to improve both physiological and behavioral circadian entrainment in aged populations

    The use of ketamine as an antidepressant: : A systematic review and meta-analysis

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    This is the peer reviewed version of the following article: Caoimhe M. Coyle, and Keith R. Laws, ‘The use of ketamine as an antidepressant: a systematic review and meta-analysis’, Human Psychopharmacology, Vol. 30 (3): 152-163, May 2015, which has been published in final form at https://doi.org/10.1002/hup.2475. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.Objective The current meta-analysis examines the effects of ketamine infusion on depressive symptoms over time in major depressive disorder (MDD) and bipolar disorder (BD). Methods Following a systematic review of the literature, data were extracted from 21 studies (n = 437 receiving ketamine) and analysed at four post-infusion time points (4 h, 24 h, 7 days and 12-14 days). The moderating effects of several factors were assessed including: repeat/single infusion, diagnosis, open-label/participant-blind infusion, pre-post/placebo-controlled design and the sex of patients. Results Effect sizes were significantly larger for repeat than single infusion at 4 h, 24 h and 7 days. For single infusion studies, effect sizes were large and significant at 4 h, 24 h and 7 days. The percentage of males was a predictor of antidepressant response at 7 days. Effect sizes for open-label and participant-blind infusions were not significantly different at any time point. Conclusions Single ketamine infusions elicit a significant antidepressant effect from 4 h to 7 days; the small number of studies at 12-14 days post infusion failed to reach significance. Results suggest a discrepancy in peak response time depending upon primary diagnosis - 24 h for MDD and 7 days for BD. The majority of published studies have used pre-post comparison; further placebo-controlled studies would help to clarify the effect of ketamine over time.Peer reviewedFinal Accepted Versio

    Prevalence and Determinants of Poor Food Intake of Residents Living in Long-Term Care

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    The final publication is available at Elsevier via http://dx.doi.org/10.1016/j.jamda.2017.05.003 © 2017. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/Poor food intake is known to lead to malnutrition in long-term care homes (LTCH), yet multilevel determinants of food intake are not fully understood, hampering development of interventions that can maintain the nutritional status of residents. This study measures energy and protein intake of LTCH residents, describes prevalence of diverse covariates, and the association of covariates with food intake. Multisite cross-sectional study. Thirty-two nursing homes from 4 provinces in Canada. From a sample of 639 residents (20 randomly selected per home), 628 with complete data were included in analyses. Three days of weighed food intake (main plate, estimated beverages and side dishes, snacks) were completed to measure energy and protein intake. Health records were reviewed for diagnoses, medications, and diet prescription. Mini-Nutritional Assessment-SF was used to determine nutritional risk. Oral health and dysphagia risk were assessed with standardized protocols. The Edinburgh-Feeding Questionnaire (Ed-FED) was used to identify eating challenges; mealtime interactions with staff were assessed with the Mealtime Relational Care Checklist. Mealtime observations recorded duration of meals and assistance received. Dining environments were assessed for physical features using the Dining Environment Audit Protocol, and the Mealtime Scan was used to record mealtime experience and ambiance. Staff completed the Person Directed Care questionnaire, and managers completed a survey describing features of the home and food services. Hierarchical multivariate regression determined predictors of energy and protein intake adjusted for other covariates. Average age of participants was 86.3 ± 7.8 years and 69% were female. Median energy intake was 1571.9 ± 411.93 kcal and protein 58.4 ± 18.02 g/d. There was a significant interaction between being prescribed a pureed/liquidized diet and eating challenges for energy intake. Age, number of eating challenges, pureed/liquidized diet, and sometimes requiring eating assistance were negatively associated with energy and protein intake. Being male, a higher Mini-Nutritional Assessment–Short Form score, often requiring eating assistance, and being on a dementia care unit were positively associated with energy and protein intake. Energy intake alone was negatively associated with homelikeness scores but positively associated with person-centered care practices, whereas protein intake was positively associated with more dietitian time. This is the first study to consider resident, unit, staff, and home variables that are associated with food intake. Findings indicate that interventions focused on pureed food, restorative dining, eating assistance, and person-centered care practices may support improved food intake and should be the target for further research.Canadian Institutes for Health Research || 201403MOP-326892-NUT-CENA-2546

    Magnetic Field Generation in Stars

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    Enormous progress has been made on observing stellar magnetism in stars from the main sequence through to compact objects. Recent data have thrown into sharper relief the vexed question of the origin of stellar magnetic fields, which remains one of the main unanswered questions in astrophysics. In this chapter we review recent work in this area of research. In particular, we look at the fossil field hypothesis which links magnetism in compact stars to magnetism in main sequence and pre-main sequence stars and we consider why its feasibility has now been questioned particularly in the context of highly magnetic white dwarfs. We also review the fossil versus dynamo debate in the context of neutron stars and the roles played by key physical processes such as buoyancy, helicity, and superfluid turbulence,in the generation and stability of neutron star fields. Independent information on the internal magnetic field of neutron stars will come from future gravitational wave detections. Thus we maybe at the dawn of a new era of exciting discoveries in compact star magnetism driven by the opening of a new, non-electromagnetic observational window. We also review recent advances in the theory and computation of magnetohydrodynamic turbulence as it applies to stellar magnetism and dynamo theory. These advances offer insight into the action of stellar dynamos as well as processes whichcontrol the diffusive magnetic flux transport in stars.Comment: 41 pages, 7 figures. Invited review chapter on on magnetic field generation in stars to appear in Space Science Reviews, Springe

    Interconnected Microphysiological Systems for Quantitative Biology and Pharmacology Studies

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    Microphysiological systems (MPSs) are in vitro models that capture facets of in vivo organ function through use of specialized culture microenvironments, including 3D matrices and microperfusion. Here, we report an approach to co-culture multiple different MPSs linked together physiologically on re-useable, open-system microfluidic platforms that are compatible with the quantitative study of a range of compounds, including lipophilic drugs. We describe three different platform designs - "4-way", "7-way", and "10-way" - each accommodating a mixing chamber and up to 4, 7, or 10 MPSs. Platforms accommodate multiple different MPS flow configurations, each with internal re-circulation to enhance molecular exchange, and feature on-board pneumatically-driven pumps with independently programmable flow rates to provide precise control over both intra- and inter-MPS flow partitioning and drug distribution. We first developed a 4-MPS system, showing accurate prediction of secreted liver protein distribution and 2-week maintenance of phenotypic markers. We then developed 7-MPS and 10-MPS platforms, demonstrating reliable, robust operation and maintenance of MPS phenotypic function for 3 weeks (7-way) and 4 weeks (10-way) of continuous interaction, as well as PK analysis of diclofenac metabolism. This study illustrates several generalizable design and operational principles for implementing multi-MPS "physiome-on-a-chip" approaches in drug discovery.United States. Army Research Office (Grant W911NF-12-2-0039

    Global Phylogeography with Mixed-Marker Analysis Reveals Male-Mediated Dispersal in the Endangered Scalloped Hammerhead Shark (Sphyrna lewini)

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    Background: The scalloped hammerhead shark, Sphyrna lewini, is a large endangered predator with a circumglobal distribution, observed in the open ocean but linked ontogenetically to coastal embayments for parturition and juvenile development. A previous survey of maternal (mtDNA) markers demonstrated strong genetic partitioning overall (global W ST = 0.749) and significant population separations across oceans and between discontinuous continental coastlines. Methodology/Principal Findings: We surveyed the same global range with increased sample coverage (N = 403) and 13 microsatellite loci to assess the male contribution to dispersal and population structure. Biparentally inherited microsatellites reveal low or absent genetic structure across ocean basins and global genetic differentiation (FST = 0.035) over an order of magnitude lower than the corresponding measures for maternal mtDNA lineages (W ST = 0.749). Nuclear allelic richness and heterozygosity are high throughout the Indo-Pacific, while genetic structure is low. In contrast, allelic diversity is low while population structure is higher for populations at the ends of the range in the West Atlantic and East Pacific. Conclusions/Significance: These data are consistent with the proposed Indo-Pacific center of origin for S. lewini, and indicate that females are philopatric or adhere to coastal habitats while males facilitate gene flow across oceanic expanses. This study includes the largest sampling effort and the most molecular loci ever used to survey the complete range of

    Altering Chemosensitivity by Modulating Translation Elongation

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    BACKGROUND: The process of translation occurs at a nexus point downstream of a number of signal pathways and developmental processes. Modeling activation of the PTEN/AKT/mTOR pathway in the Emu-Myc mouse is a valuable tool to study tumor genotype/chemosensitivity relationships in vivo. In this model, blocking translation initiation with silvestrol, an inhibitor of the ribosome recruitment step has been showed to modulate the sensitivity of the tumors to the effect of standard chemotherapy. However, inhibitors of translation elongation have been tested as potential anti-cancer therapeutic agents in vitro, but have not been extensively tested in genetically well-defined mouse tumor models or for potential synergy with standard of care agents. METHODOLOGY/PRINCIPAL FINDINGS: Here, we chose four structurally different chemical inhibitors of translation elongation: homoharringtonine, bruceantin, didemnin B and cycloheximide, and tested their ability to alter the chemoresistance of Emu-myc lymphomas harbouring lesions in Pten, Tsc2, Bcl-2, or eIF4E. We show that in some genetic settings, translation elongation inhibitors are able to synergize with doxorubicin by reinstating an apoptotic program in tumor cells. We attribute this effect to a reduction in levels of pro-oncogenic or pro-survival proteins having short half-lives, like Mcl-1, cyclin D1 or c-Myc. Using lymphomas cells grown ex vivo we reproduced the synergy observed in mice between chemotherapy and elongation inhibition and show that this is reversed by blocking protein degradation with a proteasome inhibitor. CONCLUSION/SIGNIFICANCE: Our results indicate that depleting short-lived pro-survival factors by inhibiting their synthesis could achieve a therapeutic response in tumors harboring PTEN/AKT/mTOR pathway mutations
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