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Background

Selenium and coenzyme Q10 are important antioxidants in the body. As the intake of selenium is low in Europe, and the endogenous production of coenzyme Q10 decreases as age increases, an intervention trial using selenium and coenzyme Q10 for four years was performed. As previously reported, the intervention was accompanied by reduced cardiovascular mortality. The objective of the present study was to analyze cardiovascular mortality for up to 10 years after intervention, to evaluate if mortality differed in subgroups differentiated by gender, diabetes, ischemic heart disease (IHD), and functional class.

Methods

Four-hundred forty-three healthy elderly individuals were included from a rural municipality in Sweden. All cardiovascular mortality was registered, and no participant was lost to the follow-up. Based on death certificates and autopsy results mortality was registered.

Findings

Significantly reduced cardiovascular mortality could be seen in those on selenium and coenzyme Q10 intervention. A multivariate Cox regression analysis demonstrated a reduced cardiovascular mortality risk in the active treatment group (HR: 0.51; 95%CI 0.36–0.74; P = 0.0003). The reduced mortality could be seen to persist during the 10-year period. Subgroup analysis showed positive effects in both genders. An equally positive risk reduction could be seen in those with ischemic heart disease (HR: 0.51; 95%CI 0.27–0.97; P = 0.04), but also in the different functional classes.

Conclusions

In a 10-year follow-up of a group of healthy elderly participants given four years of intervention with selenium and coenzyme Q10, significantly reduced cardiovascular mortality was observed. The protective action was not confined to the intervention period, but persisted during the follow-up period. The mechanism explaining the persistency remains to be elucidated. Since this was a small study, the observations should be regarded as hypothesis-generating.  相似文献   
3.
Aluminum geochemistry in peatland waters   总被引:4,自引:4,他引:0  
The chemical speciation of aluminum was examined in surface water samples from Sphagnum peatlands in north-central Minnesota, from peatlands along the Canadian east coast, and from bogs in the Pennine Mountain area of England. In highly organic ([DOC] 50 mg L–1 ), low pH waters, 80–90% of total dissolved Al was complexed with organic matter (OM), while in waters with low DOC ([DOC] 5 mg L–1) 54–86% of total dissolved Al existed as Al+3 or other inorganic Al species. Batch titrations of OM with Al revealed a high Al binding capacity, 1.4–2.8 mol (mg DOC)–1, that generally was unsaturated with Al. Titrations of OM with Al in conjunction with a continuous distribution model were used to determine Al-OM conditional stability constants. Binding capacity (mol Al (mg DOC)–1) and strength (formation constant) increased from pH 3 to 5 but decreased above pH 5 due to formation of AI-hydroxy species including A1(OH)3 (s). The high binding capacity of OM in bog waters facilitates metal mobility, especially in low pH (< 5) wetlands where metal solubility is high and OM concentrations are highest. Results showed that the relative degree of organic matter saturation with metal ions was important in modeling AI speciation in bog waters.  相似文献   
4.
Tumor cells develop different strategies to cope with changing microenvironmental conditions. A prominent example is the adaptive phenotypic switching between cell migration and proliferation. While it has been shown that the migration-proliferation plasticity influences tumor spread, it remains unclear how this particular phenotypic plasticity affects overall tumor growth, in particular initiation and persistence. To address this problem, we formulate and study a mathematical model of spatio-temporal tumor dynamics which incorporates the microenvironmental influence through a local cell density dependence. Our analysis reveals that two dynamic regimes can be distinguished. If cell motility is allowed to increase with local cell density, any tumor cell population will persist in time, irrespective of its initial size. On the contrary, if cell motility is assumed to decrease with respect to local cell density, any tumor population below a certain size threshold will eventually extinguish, a fact usually termed as Allee effect in ecology. These results suggest that strategies aimed at modulating migration are worth to be explored as alternatives to those mainly focused at keeping tumor proliferation under control.  相似文献   
5.
Metabolomes, as chemical phenotypes of organisms, are likely not only shaped by the environment but also by common ancestry. If this is the case, we expect that closely related species of pines will tend to reach similar metabolomic solutions to the same environmental stressors. We examined the metabolomes of two sympatric subspecies of Pinus sylvestris in Sierra Nevada (southern Iberian Peninsula), in summer and winter and exposed to folivory by the pine processionary moth. The overall metabolomes differed between the subspecies but both tended to respond more similarly to folivory. The metabolomes of the subspecies were more dissimilar in summer than in winter, and iberica trees had higher concentrations of metabolites directly related to drought stress. Our results are consistent with the notion that certain plant metabolic responses associated with folivory have been phylogenetically conserved. The larger divergence between subspecies metabolomes in summer is likely due to the warmer and drier conditions that the northern iberica subspecies experience in Sierra Nevada. Our results provide crucial insights into how iberica populations would respond to the predicted conditions of climate change under an increased defoliation in the Mediterranean Basin.  相似文献   
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Predicted increases in the frequency and duration of drought are expected to negatively affect tree vitality, but we know little about how water shortage will influence needle anatomy and thereby the trees’ photosynthetic and hydraulic capacity. In this study, we evaluated anatomical changes in sun and shade needles of 20‐year‐old Norway spruce trees exposed to artificial drought stress. Canopy position was found to be important for needle structure, as sun needles had significantly higher values than shade needles for all anatomical traits (i.e., cross‐sectional needle area, number of tracheids in needle, needle hydraulic conductivity, and tracheid lumen area), except proportion of xylem area per cross‐sectional needle area. In sun needles, drought reduced all trait values by 10–40%, whereas in shade needles, only tracheid maximum diameter was reduced by drought. Due to the relatively weaker response of shade needles than sun needles in drought‐stressed trees, the difference between the two needle types was reduced by 25% in the drought‐stressed trees compared to the control trees. The observed changes in needle anatomy provide new understanding of how Norway spruce adapts to drought stress and may improve predictions of how forests will respond to global climate change.  相似文献   
8.
Summary We describe the structure of a gene expressed in the salivary gland cells of the dipteranChironomus tentans and show that it encodes 1 of the approximately 15 secretory proteins exported by the gland cells. This sp115,140 gene consists of approximately 65 copies of a 42-bp sequence in a central uninterrupted core block, surrounded by short nonrepetitive regions. The repeats within the gene are highly similar to each other, but divergent repeats are present in a pattern which suggests that the repeat structure has been remodeled during evolution. The 42-bp repeat in the gene is a simple variant of the more complex repeat unit present in the Balbiani ring genes, encoding four of the other secretory proteins. The structure of the sp115,140 gene suggests that related repeat structures have evolved from a common origin and resulted in the set of genes whose secretory proteins interact in the assembly of the secreted protein fibers.  相似文献   
9.
We urgently need to predict species responses to climate change to minimize future biodiversity loss and ensure we do not waste limited resources on ineffective conservation strategies. Currently, most predictions of species responses to climate change ignore the potential for evolution. However, evolution can alter species ecological responses, and different aspects of evolution and ecology can interact to produce complex eco‐evolutionary dynamics under climate change. Here we review how evolution could alter ecological responses to climate change on species warm and cool range margins, where evolution could be especially important. We discuss different aspects of evolution in isolation, and then synthesize results to consider how multiple evolutionary processes might interact and affect conservation strategies. On species cool range margins, the evolution of dispersal could increase range expansion rates and allow species to adapt to novel conditions in their new range. However, low genetic variation and genetic drift in small range‐front populations could also slow or halt range expansions. Together, these eco‐evolutionary effects could cause a three‐step, stop‐and‐go expansion pattern for many species. On warm range margins, isolation among populations could maintain high genetic variation that facilitates evolution to novel climates and allows species to persist longer than expected without evolution. This ‘evolutionary extinction debt’ could then prevent other species from shifting their ranges. However, as climate change increases isolation among populations, increasing dispersal mortality could select for decreased dispersal and cause rapid range contractions. Some of these eco‐evolutionary dynamics could explain why many species are not responding to climate change as predicted. We conclude by suggesting that resurveying historical studies that measured trait frequencies, the strength of selection, or heritabilities could be an efficient way to increase our eco‐evolutionary knowledge in climate change biology.  相似文献   
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