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OBESITY AND METABOLIC SYNDROME: PLASMA LIPOPROTEINS ALTERATIONS
Full text linkObesity, especially if associated with metabolic syndrome, promotes oxidative stress, a low grade chronic inflammatory state, and modify the composition and function of plasma lipoproteins. Oxidative damage to lipoproteins not only make LDL atherogenic but can also alter HDL reducing their anti-atherogenic properties. The possibility of monitoring the lipid peroxidation of the individual regions of LDL and HDL could lead to more detailed information on the molecular mechanisms that are the basis of the increased risk of cardiovascular diseases observed in obesity and metabolic syndrome.
The object of this study was to investigate the susceptibility to peroxidation of plasma and of the hydrophobic core and the surrounding envelope of LDL and HDL in obese male (BMI between 25 and 35 Kg mq) with (SM, n=20)) or without (OB, n =40) metabolic syndrome. The susceptibility of plasma to peroxidation was higher in SM and OB than in normo-weight controls (CT, n=60), but not significant differences were observed between these two obese groups. Also the susceptibility to peroxidation of isolated LDL and HDL was higher in both obese groups than in CT. LDL and HDL in SM presented an higher content of triacylglicerols than the corresponding HDL of OB. Moreover, the hydrophobic core of HDL showed a risk of peroxidation significantly higher in SM than in OB. This last parameter was inversely correlated with the waist to hip ratio, an index of visceral obesity. This last evidence seems to indicate that the increase of inflammation typical of the visceral adipose tissue could be one of the major causes of the higher susceptibility to peroxidation found in the hydrophobic core of HDL.
The evaluation of the susceptibility to peroxidation of the core and the envelope of LDL and HDL might contribute to the identification of a subset of patients at increased risk of metabolic and cardiovascular complications. Future “ad hoc” randomized clinical trials should be designed to address the effects of weight reduction and /or different diet and/or nutritional supplementation on these parameters
Oxidative state and lipid composition of plasma from overweight and moderately obese women
No full textObjective: To determine the oxidative balance and plasma fatty acid composition of overweight and obese women.
Design: Comparative, descriptive study on 60 overweight or obese (> 25 BMI> 33), normotensive, non-diabetic women and 60 age-matched lean healthy women (BMI< 25).
Measurements: Plasma lipid, hydroperoxide, and antioxidants levels, fatty acid composition and lipoproteins susceptibility to peroxidation.
Results: Compared to the lean control group, the patient group had higher lipoprotein susceptibility to peroxidation and higher peroxide levels. On the contrary, the polyunsaturated fatty acids, in particular the omega-3 species, and the antioxidants were lower in the patient group.
Conclusions: The present study shows that overweight and obese people have oxidative balance impairment. The higher susceptibility to peroxidation of lipoproteins is the probable molecular mechanism that promotes a reduction in high unsaturated (and in particular omega-3) fatty acids, as well as antioxidants in the plasma of the overweight and obese subjects
Anti-oxidant, anti-glycant, and inhibitory activity against α-amylase and α-glucosidase of selected spices and culinary herbs
No full textAqueous and methanol extracts of dry sage, rosemary, basil, parsley, chili, garlic and onion were analyzed to investigate their
anti-oxidant and anti-glycant activities and in vitro inhibitory potential against enzymes involved in glycemic regulation.
The aqueous extracts of rosemary and sage were the richest in phenolic compounds and showed the highest ability in binding iron
and inhibiting DPPH, superoxide radicals and advanced glycation end-product production, lipid peroxidation, and the activity of
a-glucosidase and a-amylase. On the other hand, the methanol extracts of both these Labiatae were less efficient than those of
garlic, onion, parsley and chili in scavenging hydroxyl radicals. As far as protein glycation is concerned, methanol extracts were more effective in inhibiting the production of Amadori compounds and the aqueous ones in preventing advanced glycation endproduct formation. Therefore these spices may be preventive not only against cardiovascular diseases but also type 2 diabetes
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
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
Oxidizability of core and surface of lipoproteins as early marker of metabolic syndrome
No full textINTRODUCTION
Central obesity is a principal causative factor in the development of metabolic syndrome (MS), a common and complex disorder combining hypertension, insulin resistance, and alterations in the composition and function of lipoproteins. Oxidative stress is an important pathogenic mechanism of obesity-associated MS. Peroxidation of lipoproteins not only makes LDLs atherogenic but can also reduce the anti-atherogenic properties of HDL.
OBJECTIVE
The aim of this study was to investigate the oxidizability of the hydrophobic core and the surrounding envelope of LDL and HDL in obese males.
METHODS
Fifty normal-weight (CT) and 60 obese (25< BMI<35 Kg/m2 OB; 40 without MS, wMS; 20 with MS according to ATP III criteria, MS) adult males were studied. Core and surface of LDL and HDL were labeled by incubating plasma with selective pyrenic probes before isolation of lipoproteins by ultracentrifugation. Susceptibility to 2,2'-azobis-2-methyl-propanimidamide-dihydrochloride-induced peroxidation was measured following kinetically the decrease of fluorescence of the probes. The length of the lag phase and maximum velocity of the reaction were used as indices of lipoprotein oxidizability. Lipoprotein contents of proteins, cholesterol, phospholipids and triglycerides were determined by colorimetric assays.
RESULTS
The oxidizability of both core and surface were higher in both LDL and HDL of OB than in CT. The oxidizability of the two lipoprotein regions was higher in MS than in wMS, especially that of HDL core. This last parameter was inversely correlated with visceral adiposity (measured as waist to hip ratio). Moreover, triglycerides levels of LDL and HDL were higher in MS than in wMS.
CONCLUSIONS
The elevated oxidizability of lipoproteins found in MS could be due to increased oxidative stress and alterations of the composition. These preliminary results could be the rationale of future clinical trials addressed to investigate the effects of different hypocaloric diets and/or nutritional supplementations on these parameters
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