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排序方式: 共有115条查询结果,搜索用时 31 毫秒
91.
Klas Gustafsson Staffan Marklund Gunnar Aronsson Anders Wikman Birgitta Floderus 《PloS one》2015,10(6)
Purpose
The study examines various combinations of levels of social isolation in private life and peripheral work position as predictors of disability pension (DP). A second aim was to test the potential interaction effects (above additivity) of social isolation and peripheral work position on the future risk of DP, and to provide results for men and women by age.Method
The study was based on a sample of 45567 women and men from the Swedish population who had been interviewed between 1992 and 2007. Further information on DP and diagnoses was obtained from the Swedish Social Insurance Agency’s database (1993–2011). The studied predictors were related to DP using Cox’s proportional hazard regression. The analyses were stratified on sex and age (20–39 years, 40–64 years), with control for selected confounders.Results
Increased risks of DP were found for most combinations of social isolation and peripheral work position in all strata. The hazard ratios (HRs) for joint exposure to high degree of social isolation and a peripheral work position were particularly strong among men aged 20–39 (HR 5.70; CI 95% 3.74–8.69) and women aged 20–39 (HR 4.07; CI 2.99–5.56). An interaction effect from combined exposure was found for women in both age groups as well as a tendency in the same direction among young men. However, after confounder control the effects did not reach significance.Conclusions
Individuals who were socially isolated and in a peripheral work position had an increased risk of future DP. The fact that an interaction effect was found among women indicates that a combination of social isolation and peripheral work position may reinforce adverse health effects. There was no evidence that a peripheral work position can be compensated by a high degree of social intergration in private life. 相似文献92.
93.
For an infecting bacterium the human body provides several potential ecological niches with both internally (e.g. host immunity) and externally (e.g. antibiotic use) imposed growth restrictions that are expected to drive adaptive evolution in the bacterium, including the development of antibiotic resistance. To determine the extent and pattern of heterogeneity generated in a bacterial population during long-term antibiotic treatment, we examined in a monoclonal Mycobacterium tuberculosis infection antibiotic resistant mutants isolated from one patient during a 9-years period. There was a progressive accumulation of resistance mutations in the infecting clone. Furthermore, apparent clonal sweeps as well as co-existence of different resistant mutants were observed during this time, demonstrating that during treatment there is a high degree of dynamics in the bacterial population. These findings have important implications for diagnostics and treatment of drug resistant tuberculosis infections. 相似文献
94.
Malin Aronsson Matthew Low José V. López‐Bao Jens Persson John Odden John D. C. Linnell Henrik Andrén 《Ecology and evolution》2016,6(9):2957-2967
Home range (HR) size variation is often linked to resource abundance, with sex differences expected to relate to sex‐specific fitness consequences. However, studies generally fail to disentangle the effects of the two main drivers of HR size variation, food and conspecific density, and rarely consider how their relative influence change over spatiotemporal scales. We used location data from 77 Eurasian lynx (Lynx lynx) from a 16‐year Scandinavian study to examine HR sizes variation relative to prey and conspecific density at different spatiotemporal scales. By varying the isopleth parameter (intensity of use) defining the HR, we show that sex‐specific effects were conditional on the spatial scale considered. Males had larger HRs than females in all seasons. Females' total HR size declined as prey and conspecific density increased, whereas males' total HR was only affected by conspecific density. However, as the intensity of use within the HR increased (from 90% to 50% isopleth), the relationship between prey density and area showed opposing patterns for females and males; for females, the prey density effect was reduced, while for males, prey became increasingly important. Thus, prey influenced the size of key regions within male HRs, despite total HR size being independent of prey density. Males reduced their HR size during the mating season, likely to remain close to individual females in estrous. Females reduced their HR size postreproduction probably because of movement constrains imposed by dependent young. Our findings highlight the importance of simultaneously considering resources and intraspecific interactions as HR size determinants. We show that sex‐specific demands influence the importance of prey and conspecific density on space use at different spatiotemporal scales. Thus, unless a gradient of space use intensity is examined, factors not related to total HR size might be disregarded despite their importance in determining size of key regions within the HR. 相似文献
95.
96.
Amal Fadl Abdelkader Henrik Aronsson Christer Sundqvist 《Acta Physiologiae Plantarum》2010,32(5):971-978
To examine the effects of salt stress on dark-grown wheat (Triticum aestivum), seedlings of the salt-tolerant cultivar Sids 1 and the susceptible cultivar Giza 168 were grown in darkness for 14 days
in nutrient solution with and without 200 mM of supplementary salt (100 mM of NaCl and 100 mM of KCl). During this time, we
monitored their protochlorophyllide (Pchlide) contents, ratios of photoactive to non-photoactive forms of Pchlide (from 655/633-nm
emission ratios in their 77 K fluorescence emission spectra) and (following flash irradiation) ratios of newly formed chlorophyllide
(Chlide) to non-photoactive Pchlide. In addition, the accumulation of chlorophyll a in leaf sections was monitored during prolonged (24 h) irradiation. The results depended on the developmental state of the
seedlings. However, the salt stress treatment caused marked increases in both Pchlide contents in dark-grown leaves and in
Chlide contents following irradiation of leaf sections of both cultivars. The ratio of phototransformable to non-phototransformable
Pchlide and the abundance of newly formed Chlide were also increased by the salt stress. Further, leaves of salt-stressed
seedlings consistently accumulated more chlorophyll a than leaves of unstressed seedlings when floating on the nutrient solution (with or without supplementary salt) in continuous
white light. The findings are consistent with the hypothesis that increased levels of the long-wavelength form of Pchlide
contribute to protective mechanisms against salt stress. 相似文献
97.
Linda Aronsson Ying Huang Paolo Parini Marion Korach-André Janet H?kansson Jan-?ke Gustafsson Sven Pettersson Velmurugesan Arulampalam Joseph Rafter 《PloS one》2010,5(9)
Background
Intervention strategies for obesity are global issues that require immediate attention. One approach is to exploit the growing consensus that beneficial gut microbiota could be of use in intervention regimes. Our objective was to determine the mechanism by which the probiotic bacteria Lactobacillus paracasei ssp paracasei F19 (F19) could alter fat storage. Angiopoietin-like 4 (ANGPTL4) is a circulating lipoprotein lipase (LPL) inhibitor that controls triglyceride deposition into adipocytes and has been reported to be regulated by gut microbes.Methodology/Principal Findings
A diet intervention study of mice fed high-fat chow supplemented with F19 was carried out to study potential mechanistic effects on fat storage. Mice given F19 displayed significantly less body fat, as assessed by magnetic resonance imaging, and a changed lipoprotein profile. Given that previous studies on fat storage have identified ANGPTL4 as an effector, we also investigated circulating levels of ANGPTL4, which proved to be higher in the F19-treated group. This increase, together with total body fat and triglyceride levels told a story of inhibited LPL action through ANGPTL4 leading to decreased fat storage. Co-culture experiments of colonic cell lines and F19 were set up in order to monitor any ensuing alterations in ANGPTL4 expression by qPCR. We observed that potentially secreted factors from F19 can induce ANGPTL4 gene expression, acting in part through the peroxisome proliferator activated receptors alpha and gamma. To prove validity of in vitro findings, germ-free mice were monocolonized with F19. Here we again found changes in serum triglycerides as well as ANGPTL4 in response to F19.Conclusions/Significance
Our results provide an interesting mechanism whereby modifying ANGPTL4, a central player in fat storage regulation, through manipulating gut flora could be an important gateway upon which intervention trials of weight management can be based. 相似文献98.
Adaptive evolution of G-protein coupled receptor genes 总被引:2,自引:0,他引:2
The phylogeny and patterns of nucleotide substitutions in the visual
pigment genes, adrenergic receptor genes, muscarinic receptor genes, and in
the human mas oncogene were studied by comparing their DNA sequences. The
evolutionary tree obtained shows that the visual pigment genes and mas
oncogene form one cluster and that the receptor genes form another. In the
evolution of rhodopsin genes, synonymous substitutions outnumber
nonsynonymous substitutions. This is consistent with the neutral theory of
molecular evolution. However, the early evolutionary stages of alpha- and
beta-adrenergic and muscarinic receptors are notable for significantly more
nonsynonymous substitutions than synonymous substitutions, suggesting the
acquisition of novel functional adaptations. Variable rates of
nonsynonymous changes in different domains of these proteins reveal DNA
segments that might have been important in their functional adaptations.
相似文献
99.
Glyoxalase I has been purified to homogeneity from human erythrocytes. An essential part in the purification procedure involved affinity chromatography on S-hexylglutathione bound to epoxy-activated Sepharose 6B. Three isoenzymes were found, which could be separated by ion-exchange chromatography. Some of the properties of the enzyme are reported. 相似文献
100.