1,720,971 research outputs found
PROTECTIVE ROLE OF DIETARY BIOACTIVE COMPOUNDS: MECHANISMS AND HYPOTHESIS
Get PDFScientific evidences support the protective role of diets rich in fruit and vegetables against chronic diseases, like cancer and cardiovascular disease. In particular two classes of chemopreventive phytochemicals, i.e. isothiocyanates presence in Cruciferae and anthocyanins (ACNs) presence in berries and other colored fruits and vegetables, are considered in this thesis.
Cruciferae and especially Brassica genus contain high concentration of constituents with antioxidant properties (e.g. carotenoids, vitamin C, folate) as well as glucosinolate precursors of isothiocyanates (ITCs) and indoles that modulate xenobiotic biotransformation enzymes, such as Glutathione S-Transferase (GST). The protective effect of broccoli (Brassica oleracea L. var. italica) was tested through two different study protocols: a regular-intake intervention study with daily consumption of one serving of steamed broccoli for 10 days and a single-meal study (i.e. single consumption of broccoli, 250g). Analyzed broccoli resulted to be a good source of antioxidant compounds (carotenoids, vitamin C) and glucosinolates as ITCs.
Subjects involved in the study were young male smokers recruited on the basis of anthropometric characteristics, food habits and their GSTM1 genotype.
Thirty subjects were enrolled for the regular-intake study. A single blind randomized cross-over experimental design was scheduled. Fasting blood samples were collected at the beginning and at the end of each treatment period (0, 10, 30, 40 days). Concentration of carotenoids, lutein, β-carotene and folate was assessed in plasma and serum samples. Lymphocytes were used for the determination of biomarkers of oxidative stress: cell resistance against oxidative stress, endogenous DNA damage (i.e. oxidized purines), in vitro DNA repair activity and mRNA expression of OGG1, NUDT1 and HO-1 levels. Cell protection against H2O2-induced DNA damage was higher after broccoli diet with respect to control diet in the whole group of subjects. Folate and lutein concentrations increased significantly after broccoli diet. Broccoli intake caused a more consistent and significant effect of protection against DNA damage in GSTM1 null (-27.6%) subjects compared to GSTM1 positive (-13.1%) individuals (p<0.05). Oxidized purines decreased significantly (p<0.05) after broccoli intake (-22.6%) while no effect of polymorphism was observed. DNA repair activity and OGG1, HO-1 and NUDT1 mRNA expression levels did not differ throughout the intervention study.
Twelve volunteers were selected for the single-meal study. Fasting blood samples were collected before broccoli consumption and after 3, 6, 8 and 24 h from broccoli intake in order to evaluate: cell resistance to oxidative DNA damage, bioavailability of bioactive compounds (folate, lutein, β-carotene and vitamin C) and total GST activity. In particular, serum folate, plasma vitamin C and β-carotene concentrations significantly increased. Furthermore, plasma GST activity increased significantly in individuals with GSTM1 positive genotype at 6 h with respect to 3 h and 24 h but not compared to baseline. Interestingly, ex-vivo induced DNA damage was significantly reduced after 24 h from broccoli consumption.
In conclusion, these two studies demonstrated that 10 days of consumption of steamed broccoli could improve defence against DNA damage, without affecting repair activity in young healthy smokers. Moreover, a single portion of steamed broccoli was able to decrease DNA damage and to modulate GST activity. Even if preliminary, our data suggest a “diet/genetic” interaction.
Delphinidin-3-glucoside (Dp-3-glc) and cyanidin-3-glucoside (Cy-3-glc) are two ACNs able to inhibit tumor cell proliferation.
An in vitro study was designed to investigate the effect of Dp-3-glc and Cy-3-glc on the angiogenic and Dp-3-glc on the procoagulant activities of human microvascular endothelial cells (HMEC-1).
HMEC-1 were incubated for up to 24h with culture media ± ACNs (0.1, 1, 10, 100 μM) alone or in combination with purified proangiogenic factor (VEGF), or bacterial endotoxin (LPS). Angiogenesis was evaluated by the capillary-like tube formation in Matrigel and the wound healing assay; while the pro-coagulant activity was tested by the thrombin generation (TG) assay and Tissue Factor (TF) expression as antigen, one-stage recalcification assay and mRNA quantitation.
Results showed that Dp-3-glc was able to inhibit angiogenesis in resting cells and in VEGF-stimulated conditions at 100 μM; interestingly, the inhibition of the migratory VEGF-dependent stimulus started at the Dp-3-glc concentration of 1 μM. In the TG assay Dp-3-glc significantly contrasted with the pro-thrombotic stimulus of LPS starting from 10 μM on HMEC-1 intact monolayer and TF expression at 100 μM concentration. Differently, Cy-3-glc did not show any effect on angiogenesis.
In conclusion, this study, in terms of anti-angiogenic and anti-coagulant properties of Dp-3-glc make this compound a potential cancer chemopreventive agent.
Together our results, from both in vivo studies on humans and in vitro cell culture models, support potential health benefits derived from the intake of fruit (coloured berries) and vegetable (broccoli)
Genetic diversity in Italian Lactobacillus sanfranciscensis strains assessed by multilocus sequence typing and pulsed-field gel electrophoresis analyses
No full textLactobacillus sanfranciscensis is a lactic acid bacterium that characterizes the sourdough environment. The genetic differences of 24 strains isolated in different years from sourdoughs, mostly collected in Italy, were examined and compared by PFGE and multilocus sequence typing (MLST). The MLST scheme, based on the analysis of six housekeeping genes (gdh, gyrA, mapA, nox, pgmA and pta) was developed for this study. PFGE with the restriction enzyme ApaI proved to have higher discriminatory power, since it revealed 22 different pulsotypes, while 19 sequence types were recognized through MLST analysis. Notably, restriction profiles generated from three isolates collected from the same firm but in three consecutive years clustered in a single pulsotype and showed the same sequence type, emphasizing the fact that the main factors affecting the dominance of a strain are correlated with processing conditions and the manufacturing environment rather than the geographical area. All results indicated a limited recombination among genes and the presence of a clonal population in L. sanfranciscensis. The MLST scheme proposed in this work can be considered a useful tool for characterization of isolates and for indepth examination of the strain diversity and evolution of this species
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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