1,721,017 research outputs found
Branched-chain amino acids differently modulate catabolic or anabolic states in mammals : a pharmacological point of view
Full text linkSubstantial evidences have been accumulated to suggest the positive effect of branched-chain amino acid (BCAA) supplementation or BCAA-rich diets on the regulation of body weight, muscle protein synthesis, glucose homeostasis, aging process, and healthspan extension. Despite these beneficial effects, epidemiological studies have shown that altered BCAA plasma concentrations and BCAA metabolism are present in several metabolic disorders, including type 2 diabetes mellitus (T2DM) and cardiovascular diseases (CVD). In this review article, we want to give an overview of the current literature on the different effects of BCAAs in health and disease. We also intend to highlight the results showing the most promising therapeutic effects of dietary BCAA supplementation, and discuss how BCAAs can trigger different and even opposite effects, depending on the catabolic or anabolic states of the organisms. Moreover, we will consider the BCAA effects on dysmetabolism, with a mixture of different anabolic and catabolic signals. These peculiar pharmacodynamic properties may partially explain some markedly different effects found in BCAA supplementation studies. To predict accurately these effects, the overall catabolic/anabolic status of patients should be carefully considered. In wider terms, a correct modulation of dysmetabolic disorders would make nutraceutical interventions with BCAAs more effective
Sex-dependent properties of male and female human umbilical vein endothelial cells (HUVECs): focus on eNOS
No full textAtherosclerosis and cardiovascular diseases (CVDs) are classical examples of diseases where sex/gender differences have been described. A significant body of evidence suggests that CVDs are less prevalent in women than men until midlife, and the female advantage has been attributed to estrogens, which are lost with menopause. Since the earliest event in the onset of atherosclerosis and CVDs is endothelial dysfunction (ED) - a reduced release of nitric oxide (NO) coupled with an increase in Reactive Oxygen Species (ROS) in the vascular wall - many in vitro studies have been focused on endothelial cells (ECs). However, the sex of ECs has not been consistently reported in these studies, even when the effects of sex hormones were analyzed.
To better study the influence of estrogens on metabolic properties of human male and female umbilical vein ECs (HUVECs), we cultured HUVECs in a nominally hormone-free medium - consisting of a phenol-red free medium supplemented with charcoal-stripped serum (CS-FBS) - typically used to assess in vitro hormone biological activities. We found that HUVECs of both sexes stopped to grow and to sprout in the absence of hormones, and neither 17-β2 estradiol nor dihydrotestosterone reverted these inhibitory effects. We concluded that HUVEC growth and sprouting critically require some serum components - other than sex hormones - that are lost in the CS-FBS. We focused our attention on fatty acids (FAs) because: 1) metabolic pathways are emerging as important regulators of angiogenesis; 2) FAs have been crucially involved in the regulation of EC proliferation; 3) CS-FBS is fully depleted from FAs. As a matter of fact, the inhibitory effects on MTT absorbance, cell number and 3-D sprouting observed in HUVECs cultured in CS-FBS containing media were reverted by adding back sodium acetate and palmitic acid. These data confirm a fundamental role for FAs in the regulation of EC growth and sprouting. However, no substantial differences were found between male and female EC behavior in these conditions.
To further investigate inborn sex differences in ECs, we focused on a relevant issue that is the role of eNOS and of its product NO. Endothelium-produced NO has important functions on ECs themselves, playing a key role not only in CVD onset and development, but also in angiogenesis, by stimulating EC proliferation, migration and differentiation. We found that female HUVECs constitutively expressed an higher amount of eNOS both at mRNA and protein level. Moreover, female HUVECs possess greater migratory and 3-D spheroid sprouting capabilities in comparison to male cells. The increased migratory and angiogenic capabilities observed in female HUVECs were counteracted by the pretreatment with the NO synthesis inhibitor L-NAME.
These preliminary results suggest that the constitutive higher expression of eNOS observed in female HUVECs might contribute to the protection against CVDs characteristic of the younger female population. We will carry out further studies on ECs from different sources and ages to determine if the increase in eNOS expression observed in female HUVECs is preserved during lifetime and in ECs obtained from different vascular bed
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Immunological properties of embryonic and adult stem cells
No full textThe possibility of treating degenerative diseases by stem cell-based approaches is a promising therapeutical option. Among major concerns for the clinical application of stem cells, some derive from the possibility that stem cells may be rejected by the immune system as a consequence of histoincompatibility and that stem cells themselves may interfere with the normal functions of host immune response. Therefore, the immunogenicity and the immunomodulatory properties of stem cells must be carefully addressed. Although these properties are common features of different stem cell types, some peculiarities can be recognized and characterized for their proper clinical use
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
- …
