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Background

Sex steroids can positively affect the brain and from this it would follow that high levels of sex steroids could be associated with better cognitive function in older men and women.

Methods

This Healthy Ageing Study sample comprised of 521 older participants (51% women) without dementia at baseline, with an age range from 64 to 94 years. Testosterone and sex hormone binding globulin were measured using the automated Immulite 2000 and analyzed in association with baseline memory, global cognitive function and decline (assessed using the Mini-Mental Status Examination or MMSE) and controlling for potential confounds such as age, education, vascular disease, smoking, diabetes, thyroid function, and body mass index.

Results

In healthy older men and women, optimal levels of testosterone were associated with better MMSE scores at baseline. Follow-up analyses indicated that in men, low testosterone levels (OR = .94, 95% CI = .88 to 1.00) were a risk factor for a sharp cognitive decline after 2 years, perhaps indicative of dementia. Associations were independent of covariates and baseline MMSE. Conversely, women at risk for a sharp drop in cognitive function showed some evidence for higher calculated free testosterone levels at baseline.

Conclusions

Results replicate earlier cross-sectional findings that high levels of sex steroids are not associated with better cognitive function in older people. In men, age accelerated endocrinological change could be associated with dementia pathology.

General significance

These data do not support increasing testosterone levels to prevent cognitive decline in men and women over 65 years of age.  相似文献   

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The time evolution of the size distributions of (fully branched and debranched) starch molecules during in vivo and in vitro digestion was analyzed using size exclusion chromatography (SEC) and compared. In vivo digesta were collected from the small intestine of pigs fed with raw normal maize starch; in vitro digestion was carried out on the same diet fed to the pigs using a method simulating digestion in the mouth, stomach, and small intestine. A qualitative difference was observed between the in vitro and the in vivo digestion. The former showed a degradation of starch molecules to a more uniform size, whereas the in vivo digestion preserved the size distribution of native starch before producing a multimodal distribution, the heterogeneous nature of which current in vitro methods do not reproduce. The use of in vitro digestion to infer in vivo digestion patterns and, hence, potential nutrition benefits need to take account of this phenomenon.  相似文献   

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Background  

These data compare the efficacy and safety of highly purified human-derived follicle-stimulating hormone (Bravelle(R)) and recombinant follitropin-β (Follistim(R)) in women undergoing in vitro fertilization.  相似文献   

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The 'resource balance hypothesis' proposes that the species richness of grassland vegetation is potentially highest when the N:P ratio of plant tissues is 10–15 (co-limitation), so that species richness could be raised by fertilisation with N or P at sites with lower or higher N:P ratios, respectively. Here we use data from field surveys in Swiss, Dutch and American fens or wet grasslands to analyse what changes in N:P ratios might produce noticeable changes in species richness. Plant species numbers, above-ground biomass, tissue N and P concentrations and soil pH were recorded in plots of 0.06–4 m2. In each data set, plots with intermediate tissue N:P ratios (6–20) were on average most species-rich, but N:P ratios explained only 5–37% of the variation in species richness. Moreover, these effects were partially confounded with those of vegetation biomass and/or soil pH. The unique effects of N:P ratios (excluding those shared with biomass and pH) explained 11–17% of variation in species richness. The relationship between species richness and N:P ratios was asymmetric: plots with high N:P ratios were more species-poor than those with low N:P ratios. This was paralleled by a smaller species pool size at high N:P ratios (estimated from species numbers in multiple records), suggesting that fewer species are adapted to P-limited conditions than to N-limited conditions. According to these data, species richness in wetlands may possibly be raised by P-fertilisation when the initial N:P ratio of the vegetation is well above 20, but this option is not recommended for nature conservation as it might promote common species at the expense of rare ones.  相似文献   

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ABSTRACT

This article explores the practical and theoretical significance and long-term consequences of the failure to incorporate women’s interests in post-conflict negotiations by examining the case of Muslim women in India. Analyses of deeply divided societies must recognize that political competition and political violence do not affect all citizens equally. Also, the “larger picture” depicted by inter-community conflicts should not overshadow the effects of intra-community conflicts, which are no less important. Evident within each community conflict are the winners and the losers of the political accommodation process, in which the marginalized and weaker sections of each “side” of the conflict may be the real “losers”. Gendered analysis of ethnic conflicts and ethnic conflict resolution demands a reorientation of the concepts of conflict and security – Whose conflict is being solved and who is being secured?  相似文献   

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ABSTRACT

Interleukin-23 (IL-23, IL-23p19) is a proinflammatory cytokine in the IL-12-related family. Although inflammatory cells in herniated discs have been shown to contain IL-23, little is known about the presence and role of IL-23 in human disc cells. We analyzed disc specimens for IL-23 localization using immunohistochemistry in control, herniated and non-herniated discs from which annulus fibrosus (annulus) cells were isolated and cultured to identify IL-23 gene expression and production. Microarray analysis was used to assess the expression of IL-23 in disc tissue and in cells exposed to two proinflammatory cytokines, IL-1ß and TNF-α. IL-23 was present in annulus cells at the protein level and its expression was up-regulated significantly in herniated compared to control disc tissue. Direct measurement of medium components confirmed production of IL-23 and its receptor, IL-23R, by annulus cells in vitro. Annulus cells in three-dimensional culture exposed to TNF-α, but not IL-1ß, resulted in significant up-regulation of IL-23 expression compared to control cells. Our findings are evidence for the constitutive presence of IL-23 in the human disc and that its expression in vitro is modified by exposure to TNF-α.  相似文献   

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Activated charcoal is commonly used in tissue culture media. Its addition to culture medium may promote or inhibit in vitro growth, depending on species and tissues used. The effects of activated charcoal may be attributed to establishing a darkened environment; adsorption of undesirable/inhibitory substances; adsorption of growth regulators and other organic compounds, or the release of growth promoting substances present in or adsorbed by activated charcoal.  相似文献   

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The apoptosis program of physiological cell death elicits a range of non-phlogistic homeostatic mechanisms—“recognition, response and removal”—that regulate the microenvironments of normal and diseased tissues via multiple modalities operating over short and long distances. The molecular mechanisms mediate intercellular signaling through direct contact with neighboring cells, release of soluble factors and production of membrane-delimited fragments (apoptotic bodies, blebs and microparticles) that allow for interaction with host cells over long distances. These processes effect the selective recruitment of mononuclear phagocytes and the specific activation of both phagocytic and non-phagocytic cells. While much evidence is available concerning the mechanisms underlying the recognition and responses of phagocytes that culminate in the engulfment and removal of apoptotic cell bodies, relatively little is yet known about the non-phagocytic cellular responses to the apoptosis program. These responses regulate inflammatory and immune cell activation as well as cell fate decisions of proliferation, differentiation and death. Here, we review current knowledge of these processes, considering especially how apoptotic cells condition the microenvironments of normal and malignant tissues. We also discuss how apoptotic cells that persist in the absence of phagocytic clearance exert inhibitory effects over their viable neighbors, paying particular attention to the specific case of cell cultures and highlighting how new cell-corpse-clearance devices—Dead-Cert® Nanoparticles—can significantly improve the efficacy of cell cultures through effective removal of non-viable cells in the absence of phagocytes in vitro.  相似文献   

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Ohne ZusammenfassungDiese Arbeit ist bei der Zoologischen Station in Neapel ausgeführt worden. Es ist mir eine angenchme Pflicht, Herrn Prof.Dohrn und Herrn Prof.Seeeni wegen der freundlichen Unterstützung meiner Arbeit meinen aufrichtigsten Dank zu sagen.  相似文献   

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We have confirmed through an enlarged set of 728 species with 10,000 or more compiled codons, and a subset of 237 species with at least 50,000 compiled codons, that the mean values of a previously described index phi [the mean value of the ratio between the relative (G, C) content of Class II and Class I codons, where G and C are guanine and cytosine] decrease monotonically across five large taxa, viz archaea, bacteria, eukaryotes (excluding metazoa), metazoa (excluding vertebrates) and vertebrates. It is proposed that these main taxa diverge successively from an ancestral progenome along lines which have persisted over long periods of time, leading to a primordial non-symmetrical phylogenetic tree. Further divergence, i.e. from eukaryotes to plants, fungi and protozoans, has followed symmetrical branching with approximately equal numbers of replacements and fixations. A statistical analysis of the phi values of twelve distinct proteins, distributed over more than one thousand species belonging to the five main groups, was made to verify whether older taxa have older proteins. This supposition was confirmed for the first four taxa, but it was inconclusive for the last pair, metazoa/vertebrates.  相似文献   

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The classical chemotactic receptor for N-formyl peptides has traditionally been associated with polymorphonuclear and mononuclear phagocytes; however, several recent reports indicate that this receptor is also expressed in non-myeloid cells. In this study we have investigated the presence of binding sites for formyl-methionyl-leucyl-phenylalanine (fMLP) in human amniotic membranes of laboring and nonlaboring women; we have also evaluated the effect of the peptide on prostaglandin E (PGE) release from the same tissue. Our results demonstrate the presence of specific, saturable binding sites for 3H-fMLP; Scatchard plot analysis suggests the presence of both high- and low-affinity binding sites in laboring amnion, while only the low-affinity receptors were evident in nonlaboring tissue. N-t-butoxycarbonyl-methionyl-leucyl-phenylalanine (Boc-MLP), a formyl peptide receptor antagonist, inhibited 3H-fMLP binding in both preparations. In addition, fMLP was able to significantly increase PGE synthesis in perifused amnion fragments from laboring and nonlaboring women. This effect was counteracted by Boc-MLP treatment. The presence of specific binding sites for fMLP in amniotic tissue and their differing expression in laboring versus nonlaboring membranes, together with the action of the peptide on PGE synthesis, all suggest a physiological role for fMLP in labor.  相似文献   

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Body weight, body height, skinfolds, circumferences and weight indices in a population sample of 1462 women in ages between 38 and 60 years are presented. Significant age differences were noted. High correlations (r) were found between body weight and triceps and subscapular skinfolds (0.62 and 0.72 respectively) and between body weight and arm, waist and buttock circumferences (0.75-0.88). Age differences were mostly noted between 46 and 50 years of age. After that age there was a comparatively greater increase of the waist circumference than of the buttock circumference, while triceps skinfold seemed to decrease after the age of 50 indicating an altered adipose tissue distribution from the extremities to the trunk with increasing age. When taking data from a previous study of body weight in the same population of women into consideration it seems that the age differences in body weight found in cross-sectional study like the present one may to a large extent depend on differences between different cohorts studied.  相似文献   

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Cisplatinum [cis-diamminedichloroplatinum(II)] is one of the most active antitumour agents and its effect is mainly due to the formation of cisplatinum-DNA crosslinks. Formation of cisplatinum-DNA intrastrand crosslinks in nucleated white blood cells of patients was measured, both in (pretreatment) samples exposed in vitro and in cells collected immediately after in vivo exposure to cisplatinum. Large interpatient variations were found. The in vitro results showed a linear correlation with the in vivo data (cc=0.91). The in vitro measurements of crosslinks may allow prediction of response and avoidance of toxicity in individual patients.  相似文献   

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