1,720,996 research outputs found
Chronic treatment with rosuvastatin modulates nitric oxide synthase expression and reduces ischemia-reperfusion injury in rat hearts.
No full textDi Napoli P, Taccardi AA, Grilli A, De Lutiis MA, Barsotti A, Felaco M, De Caterina R. Chronic treatment with rosuvastatin modulates nitric oxide synthase expression and reduces ischemia-reperfusion injury in rat hearts. Cardiovasc Res. 2005 Jun 1;66(3):462-71. Epub 2005 Mar 2.
Laboratory of Experimental Cardiology, Department of Clinical Sciences and Bioimaging, and Center of Excellence of Aging, G. d'Annunzio University, Chieti, Italy.
OBJECTIVE: Due to reported modulatory effects of statins on nitric oxide synthase (NOS) expression, we tested the hypothesis of protective effects of in vivo chronic treatment with rosuvastatin, a novel 3-hydroxy-3-methyl-glutaryl coenzyme A-reductase inhibitor, on ischemia-reperfusion injury, and investigated mechanisms involved.
METHODS: After 3 weeks of in vivo treatment with rosuvastatin (0.2-20 mg/kg/day) or placebo, excised hearts from Wistar rats were subjected to 15 min global ischemia and 22-180 min reperfusion. We evaluated creatine-phosphokinase and nitrite levels in the coronary effluent, heart weight changes, microvascular permeability (extravasation of fluoresceine-labeled albumin), ultrastructural alterations, and the expression of endothelial (e) and inducible (i) nitric oxide synthase (NOS) (by reverse-transcription polymerase chain reaction and Western blotting).
RESULTS: Rosuvastatin 0.2 and 2 mg/kg/day significantly reduced myocardial damage and vascular hyperpermeability, concomitant with a reduction in endothelial and cardiomyocyte lesions. At 2 mg/kg/day, rosuvastatin significantly increased eNOS mRNA and protein compared with untreated hearts, and conversely decreased iNOS mRNA and protein, as well as nitrite production after ischemia-reperfusion. The addition of the NOS inhibitor N(omega)-nitro-L-arginine methylester (L-NAME, 30 micromol/L) significantly reduced cardioprotection against ischemia-reperfusion.
CONCLUSIONS: Chronic treatment with rosuvastatin before ischemia reduces ischemia-reperfusion injury and prevents coronary endothelial cell and cardiomyocyte damage by NO-dependent mechanisms
Modulation of MCP-1 and iNOS by 50 Hz sinusoidal electromagnetic field.
No full textThe purpose of this study was to investigate whether overnight exposure to 1 mT-50 Hz extremely low-frequency sinusoidal electromagnetic field (EMF) affects the expression and production of inducible nitric oxide synthase (iNOS) and monocyte chemotactic protein-1 (MCP-1) in human monocytes. RT-PCR and Western blot analysis demonstrate that EMF exposure affects the expression of iNOS and MCP-1 in cultured human mononuclear cells at the mRNA level and protein synthesis. Interestingly, the effects of EMF exposure clearly differed with respect to the potentiation and inhibition of iNOS and MCP-1 expression. Whereas iNOS was down-regulated both at the mRNA level and at the protein level, MCP-1 was up-regulated. These results provide helpful information regarding the EMF-mediated modulation of the inflammatory response in vivo. However, additional studies are necessary to demonstrate that EMF acts as a nonpharmacological inhibitor of NO and inducer of MCP-1 in some diseases where the balance of MCP-1 and NO may be important
Chronic treatment with rosuvastatin modulates nitric oxide synthase expression and reduces ischemia-reperfusion injury in rat hearts
No full textObjective: Due to reported modulatory effects of statins on nitric oxide synthase (NOS) expression, we tested the hypothesis of protective
effects of in vivo chronic treatment with rosuvastatin, a novel 3-hydroxy-3-methyl-glutaryl coenzyme A-reductase inhibitor, on ischemia–
reperfusion injury, and investigated mechanisms involved.
Methods: After 3 weeks of in vivo treatment with rosuvastatin (0.2–20 mg/kg/day) or placebo, excised hearts from Wistar rats were subjected
to 15 min global ischemia and 22–180 min reperfusion. We evaluated creatine-phosphokinase and nitrite levels in the coronary effluent, heart
weight changes, microvascular permeability (extravasation of fluoresceine-labeled albumin), ultrastructural alterations, and the expression of
endothelial (e) and inducible (i) nitric oxide synthase (NOS) (by reverse-transcription polymerase chain reaction and Western blotting).
Results: Rosuvastatin 0.2 and 2 mg/kg/day significantly reduced myocardial damage and vascular hyperpermeability, concomitant with a
reduction in endothelial and cardiomyocyte lesions. At 2 mg/kg/day, rosuvastatin significantly increased eNOS mRNA and protein compared
with untreated hearts, and conversely decreased iNOS mRNA and protein, as well as nitrite production after ischemia–reperfusion. The
addition of the NOS inhibitor NE-nitro-l-arginine methylester (l-NAME, 30 Amol/L) significantly reduced cardioprotection against
ischemia–reperfusion.
Conclusions: Chronic treatment with rosuvastatin before ischemia reduces ischemia–reperfusion injury and prevents coronary endothelial
cell and cardiomyocyte damage by NO-dependent mechanism
The role of inducible nitric oxide synthase and haem oxygenase 1 in growth and development of dental tissue'
No full textIn this study, the activity of the antioxidant enzyme network was assessed spectrophotometrically in samples of dental pulp and dental papilla taken from third-molar gem extracts. The production of nitric oxide by the conversion of l-(2,3,4,5)-[3H] arginine to l-(3H) citrulline, the activity of haem oxygenase 1 (HO-1) through bilirubin synthesis and the expression of inducible nitric oxide synthase (iNOS), HO-1 proteins and messenger RNA by Western blot and reverse-transcribed polymerase chain reaction were also tested. The objective of this study was to evaluate the role of two proteins, iNOS and HO-1, which are upregulated by a condition of oxidative stress present during dental tissue differentiation and development. This is fundamental for guaranteeing proper homeostasis favouring a physiological tissue growth. The results revealed an over-expression of iNOS and HO-1 in the papilla, compared with that in the pulp, mediated by the nuclear factor kappa B transcription factor activated by the reactive oxygen species that acts as scavengers for the superoxide radicals. HO-1, a metabolically active enzyme in the papilla, but not in the pulp, seems to inhibit the iNOS enzyme by a crosstalk between the two proteins. We suggest that the probable mechanism through which this happens is the interaction of HO-1 with haem, a cofactor dimer indispensible for iNOS, and the subsequent suppression of its metabolic activit
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
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