1,720,973 research outputs found
A critical assessment of the effects of aminoguanidine and ascorbate on the oxidative modification of LDL: evidence for interference with some assays of lipoprotein oxidation by aminoguanidine
No full textSeveral lines of evidence support a role for oxidized low density lipoprotein (LDL) in the genesis of the atherosclerotic lesion. Hence, the effect of compounds with antioxidant properties on LDL oxidation assumes great significance. Ascorbate, a potent water-soluble chain-breaking antioxidant, has been shown to inhibit LDL oxidation. Aminoguanidine (AMG) is a pharmacological inhibitor of advanced non-enzymatic glycosylation. Recently it has been suggested that aminoguanidine might have an inhibitory effect on LDL oxidation, but total lipid peroxidation assayed by conjugated diene formation was not inhibited. Thus, in this study, we compared the effect of aminoguanidine with ascorbate to obtain a better appreciation of the effect of AMG on Cu(2+)-catalyzed LDL oxidation. Oxidative modification of LDL was monitored by assaying intermediates and end products of lipid peroxidation, conjugated dienes (CD), lipid peroxides (LPO), and relative electrophoretic mobility (REM). Apolipoprotein B-100 modification (increased fluorescence, fragmentation on SDS-PAGE, and 125I-labeled LDL degradation by human macrophages) was also measured. Ascorbate (100 microM) inhibited LDL oxidation by > 95%, as evidenced by all of the selected indices. Aminoguanidine (20 mM) substantially decreased thiobarbituric acid-reactive substances (TBARS) activity and lipid peroxide formation, but only partially prevented the increase of REM (-55%), apoB fluorescence (-39%), and degradation by macrophages (-54%). Unlike ascorbate, AMG failed to preserve alpha-tocopherol in LDL, prevent apoB-100 fragmentation, or inhibit conjugated diene formation during LDL oxidation. Furthermore, incubation of AMG with already oxidized LDL resulted in a significant decrease in TBARS activity and LPO, and 26.9% decrease in the REM of LDL.(ABSTRACT TRUNCATED AT 250 WORDS
Red wine with a single high peroxide meal reduces the increased susceptibility to oxidation of postprandial low dendity lipoproteins
No full textSelenium supplementation prevents the increase in atherogenic electronegative LDL (LDL minus) in the postprandial phase
No full textEvidence is accumulating that postprandial phenomena play a role in atherogenesis. Dietary lipid hydroperoxides that escape from the gastrointestinal barrier can be incorporated into plasma lipoproteins, leading to a modified form of LDL (LDL minus). The present human study was designed to investigate the effect of selenium supplementation on the formation of LDL minus in the postprandial phase. Fourteen healthy subjects ate the same test meal, high in lipid hydroperoxides, at baseline and after 10-day selenium supplementation (110 μg/day). Plasma selenium, LDL minus, LDL resistance to oxidative modification, plasma antioxidants (ascorbic acid, GSH and GPx activity) and MDA were measured in preprandial (time 0) and postprandial (3 h) phases. Supplementation did not induce changes in the concentration of selenium in fasting plasma, but, at the same time, it induced a significant decrease in preprandial plasma GPx activity and inhibited the meal-induced increase in GPx activity. Selenium..
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
Changing the Mediterranean diet: effects on blood pressure.
No full textAn increase in the polyunsaturated to saturated fatty acid ratio (P:S) in the diet has been reported to reduce blood pressure in man. We have investigated whether an increase in the percentage of saturated fatty acids in the typical Mediterranean diet would affect blood pressure in a sample of healthy rural population of southern Italy. Fifty-seven non-hospitalized normotensive volunteers (29 male, 28 female, aged 30-50 years) were studied. After a 2-week baseline period on their customary diet (P:S = 0.44), they underwent a 6-week isocaloric dietary intervention with a 70\% increase in energy from saturated fatty acids and a corresponding decrease in carbohydrate and mono-unsaturated fat (P:S = 0.23). Thereafter they returned to their usual diet and were followed-up for 6 more weeks (switch-back period). By the end of the intervention period, systolic pressure was increased by 2.6 mmHg in men (P less than 0.05) and by 4.8 mmHg in women (P less than 0.01). Diastolic pressure was not significantly increased, although a significant linear regression of the group average blood pressure over time was observed for both systolic (0.161 mmHg, P less than 0.01) and diastolic pressure (0.107 mmHg, P less than 0.01). After returning to their customary diet, blood pressure returned to baseline (-0.212 mmHg, P less than 0.05 systolic and -0.226 mmHg, P less than 0.01 diastolic). No significant change in body weight occurred throughout the study. These findings suggest that changes in the saturated fatty acid content of the diet with moderate change in the dietary P:S ratio can influence blood pressure to a significant extent
Growth conditions and abiotic factors affect final concentration of bioactive compounds in broccoli sprouts
No full textThe beneficial effects of Brassica vegetables on human health have been attributed to their complex mixture of phytochemicals such as glucosinolates and anthocyanins.
Glucosinolates have attracted great interest from both toxicological and pharmacological point of view, as they are able to induce phase 2 detoxication enzymes and protect animals against chemically induced cancer. Young broccoli plants are an especially good source of chemoprotective glucosinolates, whose levels are greater than in mature plants.
Anthocyanins, responsible for the red, purple and blue colours of many vegetables and fruits, have been reported to be antioxidants and vasoprotectors, inhibit inflammation and the growth of cancerous cells and have anti-obesity effects.
The quali-quantitative composition of bioactive compounds in vegetables is strongly affected by various factors, such as, growing conditions and abiotic stresses.
In this work, the influence of different light and temperature regimes, as well as, of some chemical and hormonal treatments on glucosinolates and anthocyanins production in broccoli sprouts was investigated.
A rapid and sensitive LC-MS/MS (MRM) method was developed to analysed and quantify glucosinolates in broccoli sprouts. Total anthocyanins content was determined by a spectrophotometric method and by HPLC-DAD.
The results showed that glucosinolates and anthocyanins content significantly increased in broccoli sprouts exposed to light respect to sprouts grown in the dark. Also, abiotic stresses (sucrose, mannitol, NaCl) and some hormones involved in plant stress responses were able to increase accumulation of anthocyanins and glucosinolates, with sucrose being the most effective one.
This work was supported by Italian Ministry of Agriculture, Food & Forestry (MiPAAF) grant “NUTRIGEA” (DM 30281 23/12/2009)
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