6,686 research outputs found
Changes in intervertebral disc morphology persist 5 mo after 21-day bed rest
No full textAs part of the nutrition-
countermeasures (NUC) study in Cologne, Germany in 2010,
seven healthy male subjects underwent 21 days of head-down tilt bed
rest and returned 153 days later to undergo a second bout of 21-day
bed rest. As part of this model, we aimed to examine the recovery of
the lumbar intervertebral discs and muscle cross-sectional area (CSA)
after bed rest using magnetic resonance imaging and conduct a pilot
study on the effects of bed rest in lumbar muscle activation, as
measured by signal intensity changes in T2-weighted images after a
standardized isometric spinal extension loading task. The changes in
intervertebral disc volume, anterior and posterior disc height, and
intervertebral length seen after bed rest did not return to prebed-rest
values 153 days later. While recovery of muscle CSA occurred after
bed rest, increases (P 0.016) in multifidus, psoas, and quadratus
lumborum muscle CSA were seen 153 days after bed rest. A trend was
seen for greater activation of the erector spinae and multifidus muscles
in the standardized loading task after bed rest. Greater reductions of
multifidus and psoas CSA muscle and greater increases in multifidus
signal intensity with loading were associated with incidence of low
back pain in the first 28 days after bed rest (P 0.044). The current
study contributes to our understanding of the recovery of the lumbar
spine after 21-day bed rest, and the main finding was that a decrease
in spinal extensor muscle CSA recovers within 5 mo after bed rest but
that changes in the intervertebral discs persist
Voeding van de oudere mens
No full textAls de mens ouder wordt, treden er fysiologische veranderingen op en komen ziekte en beperkingen vaker voor. Deze veranderingen hebben onder meer effect op de energiebehoefte en op de eiwitbehoefte. Volgens de huidige inzichten is van de micronutriënten alleen de behoefte aan vitamine D verhoogd. Deze bedraagt voor 70-plussers 20 μg/dag. Voor ogenschijnlijk gezonde ouderen verandert de behoefte aan andere vitaminen en mineralen nauwelijks. Dat betekent dat bij een verlaagde energie-inneming de vitamine- en mineralendichtheid van de voeding moet toenemen. Dit kan bereikt worden door een verschuiving in de voedselkeuze, wat niet eenvoudig te bereiken is bij ouderen met weinig eetlust. Behalve fysiologische veranderingen en ziekten kunnen medicijngebruik en sociaal-psychologische problemen een effect hebben op de voedingsgewoonten. In dit hoofdstuk worden de meest gesignaleerde problemen in de voeding van ouderen besproken en er worden enkele praktische adviezen gegeven
Prevention of bone loss during 56 days of strict bed rest by side-alternating resistive vibration exercise
No full textBed rest is a recognized model for muscle atrophy and bone loss in space flight and in clinical medicine. We
hypothesized that whole body vibration in combination with resistive exercise (RVE) would be an effective
countermeasure.
Twenty healthy male volunteers underwent horizontal bed rest for 56 days and were randomly assigned
either to a group that performed RVE 11 times per week or to a group that underwent bed rest only (Ctrl).
Bone mineral content (BMC) was assessed by peripheral quantitative computed tomography (pQCT) in the
tibia and the radius and by dual x-ray absorptiometry (DXA) in the hip and lumbar spine at baseline and at
regular intervals during bed rest and a 12-month follow-up.
RVE appeared to protect muscle size and function, and it also prevented bone loss (p-values between b0.001
and 0.01). Bone losses were largest in the distal tibia epiphysis, where BMC declined from 421.8 mg/mm (SD
51.3) to 406.6 mg/mm (SD 52.7) in Ctrl, but only from 411.1 mg/mm (SD 56.6) to 409.6 mg/mm (SD 66.7)
in RVE. Most of the BMC losses were recovered by 12-month follow-up. Analyses showed that the epiphyseal
cortex, rather than spongiosa, depicted the most pronounced changes during bed rest and recovery.
These results suggest that the combined countermeasure applied in this study is effective to prevent bone
losses from the tibia. This underlines the importance of mechanical usage for the maintenance of the human
skeleton
Fish fatty acids and mental health in older people
No full textBackground It has been suggested that the intake of fish and marine n-3 polyunsaturated fatty acids could protect against age-related cognitive decline and impaired mental well-being. However, results from observational studies are inconclusive and data from randomized controlled trials in older people without clinical dementia or depression are scarce. The objective of this thesis was to investigate the effect of daily supplementation with eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on cognitive performance and mental well-being in an older non-clinical population. We also examined the effect of fish oil on gene expression profiles in white blood cells to identify early changes in pathways possibly related to mental health. Furthermore, we assessed the association of fish and EPA+DHA intake with mental health in different aging populations. Methods The effect of low and high doses of EPA+DHA (400 and 1,800 mg per day, respectively) on cognitive performance, several measures of mental well-being, and gene expression was examined in a 26-week randomized, double-blind, placebo-controlled trial. This study was conducted in 302 individuals aged 65 years or older with no clinical diagnosis of dementia or depression. Furthermore, the cross-sectional association between fatty fish and EPA+DHA intake with cognitive performance and the association with cognitive change during 6 years of follow-up was assessed in 1,025 aging US men who participated in the Veterans Affairs Normative Aging Study (NAS). In addition, the associations of EPA+DHA and fish intake with depressive symptoms and dispositional optimism were assessed in 644 free-living Dutch subjects with a history of myocardial infarction. Results Daily intake of low or high doses of EPA+DHA did not affect cognitive performance, mental well-being, anxiety, or quality of life, after 13 or 26 weeks of intervention. However, treatment with EPA+DHA for 26 weeks altered gene expression in white blood cells to a more anti-inflammatory and more anti-atherogenic profile. In elderly US men we found no association of fatty fish or EPA+DHA intake with cognitive performance or 6-year cognitive change. Intake of EPA+DHA was positively associated with dispositional optimism in subjects with a history of myocardial infarction. There was also a tendency for less depressive symptoms with a higher EPA+DHA or fish intake, but this association was no longer statistically significant after controlling for confounders. Conclusion Supplemental intake of EPA+DHA is unlikely to have a short-term impact on cognitive performance or mental well-being of older people without a clinical diagnosis of dementia or depression. Whether long-term intake of EPA+DHA and fish could be beneficial to the maintenance of cognitive performance or mental well-being of older people in Western populations still needs to be established. <br/
De Vaart der Volkeren: Buitenlandse bedrijven en hun werknemers in Amsterdam en de rest van Nederland
No full textOp basis van de analyses in dit onderzoek komen we tot de volgende conclusies: • Buitenlandse bedrijven vertegenwoordigen bijna 13 procent van de werkgelegenheid in Nederland; • De werkgelegenheid in buitenlandse bedrijven komt voor 66 procent van bedrijven met een Europese eigenaar en voor 23 procent van bedrijven met een eigenaar uit de Verenigde Staten; • In absolute aantallen zijn groothandel, detailhandel en financiële instellingen de grootste sectoren gemeten naar buitenlandse werkgelegenheid; • In vergelijking met de totale omvang van de sectoren is het aandeel van buitenland-se werkgelegenheid relatief groot bij de winning van delfstoffen, de industrie en ver-voer en communicatie; • Amsterdam gaat in Nederland onbetwist aan kop als het gaat om buitenlandse eco-nomische bedrijvigheid: o Van de totale nationale werkgelegenheid bij buitenlandse bedrijven bevindt zich 19 procent in Amsterdam en Haarlemmermeer en 28 procent in de Me-tropoolregio Amsterdam; o In Amsterdam komt de meeste buitenlandse werkgelegenheid van financiële instellingen, groothandel en holdings; o In vergelijking met de rest van Nederland vertegenwoordigen buitenlandse bedrijven een groot deel van de werkgelegenheid in Amsterdam voor financi-ele instellingen, zakelijke dienstverlening en logiesverstrekking; o Buitenlandse bedrijven trekken binnen Nederland per saldo naar Amsterdam, maar het gaat om kleine aantallen (100 in zes jaar tijd); o Veel migratie vindt plaats binnen de regio Groot-Amsterdam; • Buitenlandse bedrijven zijn na correctie voor omvang en regio gemiddeld ongeveer 30 procent productiever dan Nederlandse bedrijven in dezelfde sector; • Buitenlandse bedrijven betalen hogere lonen dan Nederlandse bedrijven; • Dit geldt ook als we alleen kijken naar werknemers die gelijktijdig of volgtijdelijk werkten bij zowel een Nederlands als een buitenlands bedrijf; • Buitenlandse bedrijven beïnvloeden de innovativiteit en productiviteit van andere be-drijven in de nabijheid (binnen de gemeente) niet méér dan een identiek Nederlands bedrijf. We vinden dus geen extra agglomeratie-effect door nabijheid (binnen de ge-meente) tot buitenlandse bedrijven of werknemers
The effects of pre-exhaustion, exercise order, and rest intervals in a full-body resistance training intervention
No full textPre-exhaustion (PreEx) training is advocated on the principle that immediately preceding a compound exercise with an isolation exercise can target stronger muscles to pre-exhaust them to obtain greater adaptations in strength and size. However, research considering PreEx training method is limited. The present study looked to examine the effects of a PreEx training programme. Thirty-nine trained participants (male = 9, female = 30) completed 12 weeks of resistance training in 1 of 3 groups: a group that performed PreEx training (n = 14), a group that performed the same exercise order with a rest interval between
exercises (n = 17), and a control group (n = 8) that performed the same exercises in a different order (compound exercises prior to isolation). No significant between-group effects were found for strength in chest press, leg press, or pull-down exercises, or for body composition changes. Magnitude of change was examined for outcomes also using effect size (ES). ESs for strength changes were considered large for each group for every exercise (ranging 1.15 to 1.62). In conclusion, PreEx training offers no greater benefit to performing the same exercises with rest between them compared with exercises performed in an order that prioritises compound movements
A framework to identify epigenome and transcription factor crosstalk
No full textWhile changes in chromatin are integral to transcriptional reprogramming during cellular differentiation, it is currently unclear how chromatin modifications are targeted to specific loci. To systematically identify transcription factors (TFs) that can direct chromatin changes during cell fate decisions, we model the genome-wide dynamics of chromatin marks in terms of computationally predicted TF binding sites. By applying this computational approach to a time course of Polycomb-mediated H3K27me3 marks during neuronal differentiation of murine stem cells, we identify several motifs that likely regulate dynamics of this chromatin mark. Among these, the motifs bound by REST and by the SNAIL family of TFs are predicted to transiently recruit H3K27me3 in neuronal progenitors. We validate these predictions experimentally and show that absence of REST indeed causes loss of H3K27me3 at target promoters in trans, specifically at the neuronal progenitor state. Moreover, using targeted transgenic insertion, we show that promoter fragments containing REST or SNAIL binding sites are sufficient to recruit H3K27me3 in cis, while deletion of these sites results in loss of H3K27me3. These findings illustrate that the occurrence of TF binding sites can determine chromatin dynamics. Local determination of Polycomb activity by Rest and Snail motifs exemplifies such TF based regulation of chromatin. Furthermore, our results show that key TFs can be identified ab initio through computational modeling of epigenome datasets using a modeling approach that we make readily accessible
DNS of transition to nonuniform in time and/or space turbulent flows in rotating spherical layers
No full textWe have numerically studied the transition to turbulence in a layer of a viscous incompressible fluid confined between concentric counter rotating spherical boundaries. Rotational speeds of one or two boundaries were periodically modulated. The transition to turbulence was caused by an increase in the modulation amplitude. Two different cases of transitions were under consideration. In the first case modulation of outer sphere velocity with constant inner sphere speed was imposed on initial periodical flow state. The obtained solutions reveal cycle-chaos intermittency type - irregular temporal alternation of laminar and turbulent states occupying the whole layer. In the second case both of spheres were opposite-phase oscillated at the same frequency and amplitude about the state of rest. The obtained solutions exhibits chaos-chaos intermittency type of the flow - irregular temporal alternation of weak and strong turbulent states in the limited part of the layer, outside which the flow remains periodical
Vitaal naar de eindstreep
No full textHoe worden we gezond oud? Trainen en extra eiwitten werken, blijkt uit onderzoek van de afdeling Humane voeding. Over het effect van vitamines en omega-3 vetzuren is het laatste woord nog niet gezegd
Nutrition, the unrecognized determinant in Alzheimer’s disease
No full textIn conclusion, we observed a decline in nutritional status early in the disease process, and a further decline with progression of disease. This poorer nutritional status is most likely due to an elevated energy expenditure in rest, rather than a reduced dietary intake. Despite an adequate threshold for odors, poorer memory was associated with impaired discrimination and identification of odors. Taste function or food preferences were not affected and are therefore unlikely to affect dietary intake in memory clinic patients. These results are of clinical importance as preventing a decline in nutritional status might be beneficial for maintaining cognitive function, given the higher risk of clinical progression in patients with a poorer nutritional status. Although confirmation is needed, our results suggest that nutritional status and dietary intake are relevant targets for interventions in memory clinic patients
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