1,720,978 research outputs found
Evidence for carbon tetrachloride-induced lipid peroxidation in vivo by 23Na relaxation times t1
No full textWe report here the results of a study performed on the livers of rats intoxicated with CCl4 in order to investigate the dependence of 23Na n.m.r. parameters on specific cell alterations. In this connection, CCl4 represents a useful probe, since the hepatocellular damaging effects induced by this aliphatic halocarbon have been extensively investigated.
The t1relaxationtimes of intracellular sodium ion under physiological conditions in the presence of the paramagnetic shift reagent dysprosium tripolyphosphate were investigated. The significant increase of t1 in the livers of rats intoxicated with CCl4 with respect to the t1relaxationtimes of normal rats was studied.
Evidence is given that neither liver cell necrosis nor fat accumulation nor proliferative processes affected the observed t1 lengthening. However, when t1relaxationtimes were measured in the livers of vitamin E-treated rats subsequently intoxicated with CCl4 a significant shortening of t1 with respect to the times measured in intoxicated rats was observed. We report the results of the present study, taking into consideration that peroxidation of microsomal lipids is the key factor in the CCl4-induced liver injury process and that vitamin E exerts an antioxidant action against CCl4-induced microsomal lipidperoxidation
Protective effect of olive oil minor polar components against oxidative damage in rats treated with ferric-nitrilotriacetate
No full textThe phenolic fraction of virgin olive oil exerts preventive effects against reactive oxygen species mediated degenerative diseases. To investigate its action as inhibitor of lipid peroxidation in vivo, we treated Wistar rats with olive oil minor polar components (MPC) (25-50 mg/kg bw) prior to the administration of a sublethal dose (15 mg Fe/kg bw) of ferric-nitrilotriacetate (Fe-NTA). lntraperitoneal injection (i.p.) of Fe-NTA lead to increased oxidative stress associated with extensive peroxidation of membrane lipids in plasma, kidney, and liver of treated rats. Fe-NTA treatment induced a significant decrease of the major oxidizable membrane lipids, alpha-tocopherol, fatty acids and cholesterol, together with an increase of fatty acids hydroperoxides (HP) and 7-ketocholesterol (7-keto). I.p. administration of MPC significantly inhibited fatty acids and cholesterol oxidation, and reduced the levels of HP and 7-keto. In summary, MPC administration protects organs against lipid peroxidation and conserves the endogenous alpha-tocopherol. (c) 2007 Elsevier Ltd. All rights reserved
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
Effect of storage conditions on lipid components and color of Mugil cephalus processed roes
No full textThe salted and semidried mullet (Mugil cephalus) ovary product (bottarga) is proposed as an important source of
the long-chain n−3 polyunsaturated fatty acids (PUFA), eicosapentaenoic acid, and docosahexaenoic acid. In this work,
we investigated the extent of lipid oxidation and browning of grated bottarga samples during 7 mo of storage at −20 ◦C,
2 to 3 ◦C in the absence of light, and at room temperature in the presence or absence of light. Modifications of the
levels of total choline (as index of phospholipid breakdown), total sugars, and free amino acids such as lysine, methionine,
and tryptophan (involved in nonenzymatic browning) were also studied at different storage conditions. Storage of
bottarga did not significantly affect the n−3 PUFA and cholesterol levels with respect to the control; nevertheless, a
significant hydroperoxide increase was observed during 7 mo in bottarga samples at all the storage conditions, while
low malondialdeyde levels were measured. Samples placed at room temperature in the absence and in the presence of
light showed over time a marked browning process, lipid breakdown, a sensible decrease in the levels of total sugars,
tryptophan, and methionine with respect to control and samples stored at −20 ◦C and 2 to 3 ◦C. The resistance against
the oxidation of the isolated bottarga lipids was also assessed in dry state at several temperatures (37, 75, and 140 ◦C)
Recognition and quantitation of cis-vaccenic and eicosenoic fatty acids in olive oils by 13C nuclear magnetic resonance spectroscopy
No full textNovel Approach to Study Oxidative Stability of Extra Virgin Olive Oils: Importance of a-Tocopherol Concentration
No full textH2O2 oxidative activity: modulatory effect of hydroxytyrosol
No full textHydroxytyrosol (HT) is the major o-diphenol present in extra-virgin
olive oil, either in free or esterified form, once absorbed, is present in
high amount in the kidney, where it may exert a proctetive action. In this
study we monitored the ability of HT to protect renal cells (LLC-PK1)
against oxidative damage induced by H2O2. The peroxidation of lipid represents
a primary consequences of cellular oxidative stress, leading to
biophysical changes that disrupt membrane and organelle function; moreover
oxidative stress is a process that may stimulate cellular signalling
pathways, usually associated with the promotion of cellular death. HT
exerted a significant antioxidant action, inhibiting the production of
fatty acids hydroperoxides and 7-ketocholesterol induced by H2O2 treatment
and thus preserving the membrane lipids. It has been shown that
oxidative stress in LLC-PK1 cells is related also to the changes in the
phosphorylation state of pro-death signalling pathways ERK1/2 and the
pro-survival signalling Akt/PKB. Pretreatment with HT is able to modulate
H2O2-induced changes in the phosphorylation state of ERK1/2
and Akt/PKB. We suggest that one potential protective mechanism of
olive oil polyphenols in kidney cells may be attributed to interactions
with intracellular signalling pathways activated in response to oxidative
stress
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
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