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Search Results: 1 - 10 of 612670 matches for " Andréa C. Celotto "
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The Effect of Extracellular pH Changes on Intracellular pH and Nitric Oxide Concentration in Endothelial and Smooth Muscle Cells from Rat Aorta
Verena K. Capellini, Carolina B. A. Restini, Lusiane M. Bendhack, Paulo R. B. Evora, Andréa C. Celotto
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0062887
Abstract: Aims It has been known for more than a century that pH changes can alter vascular tone. However, there is no consensus about the effects of pH changes on vascular response. In this study, we investigated the effects of extracellular pH (pHo) changes on intracellular pH (pHi) and intracellular nitric oxide concentration ([NO]i) in freshly isolated endothelial cells and cross sections from rat aorta. Main Methods The HCl was used to reduce the pHo from 7.4 to 7.0 and from 7.4 to 6.5; the NaOH was used to increase the pHo from 7.4 to 8.0 and from 7.4 to 8.5. The fluorescent dyes 5-(and-6)-carboxy SNARF-1, acetoxymethyl ester, acetate (SNARF-1) and diaminofluorescein-FM diacetate (DAF-FM DA) were employed to measure the pHi and [NO]i, respectively. The fluorescence intensity was measured in freshly isolated endothelial cells by flow cytometry and in freshly obtained aorta cross sections by confocal microscopy. Key Findings The endothelial and vascular smooth muscle pHi was increased at pHo 8.5. The extracellular acidification did not change the endothelial pHi, but the smooth muscle pHi was reduced at pHo 7.0. At pHo 8.5 and pHo 6.5, the endothelial [NO]i was increased. Both extracellular alkalinization and acidification increased the vascular smooth muscle [NO]i. Significance Not all changes in pHo did result in pHi changes, but disruption of acid-base balance in both directions induced NO synthesis in the endothelium and/or vascular smooth muscle.
The protective effect of cilostazol on isolated rabbit femoral arteries under conditions of ischemia and reperfusion: the role of the nitric oxide pathway
Santos, Mariana R.G.A.;Celotto, Andréa C.;Capellini, Verena K.;Evora, Paulo R. B.;Piccinato, Carlos E.;Joviliano, Edwaldo E.;
Clinics , 2012, DOI: 10.6061/clinics/2012(02)13
Abstract: objectives: the clinical significance of ischemia/reperfusion of the lower extremities demands further investigation to enable the development of more effective therapeutic alternatives. this study investigated the changes in the vascular reactivity of the rabbit femoral artery and nitric oxide metabolites under partial ischemia/ reperfusion conditions following cilostazol administration. methods: ischemia was induced using infrarenal aortic clamping. the animals were randomly divided into seven groups: control 90 minutes, ischemia/reperfusion 90/60 minutes, control 120 minutes, ischemia/reperfusion 120/90 minutes, cilostazol, cilostazol before ischemia/reperfusion 120/90 minutes, and ischemia 120 minutes/cilostazol/ reperfusion 90 minutes. dose-response curves for sodium nitroprusside, acetylcholine, and the calcium ionophore a23187 were obtained in isolated femoral arteries. the levels of nitrites and nitrates in the plasma and skeletal muscle were determined using chemiluminescence. results: acetylcholine-and a23187-induced relaxation was reduced in the ischemia/reperfusion 120/90 group, and treatment with cilostazol partially prevented this ischemia/reperfusion-induced endothelium impairment. only cilostazol treatment increased plasma levels of nitrites and nitrates. an elevation in the levels of nitrites and nitrates was observed in muscle tissues in the ischemia/reperfusion 120/90, cilostazol/ischemia/reperfusion, and ischemia/ cilostazol/reperfusion groups. conclusion: hind limb ischemia/reperfusion yielded an impaired endothelium-dependent relaxation of the femoral artery. furthermore, cilostazol administration prior to ischemia exerted a protective effect on endotheliumdependent vascular reactivity under ischemia/reperfusion conditions.
Oxidative stress is not associated with vascular dysfunction in a model of alloxan-induced diabetic rats
Capellini, Verena Kise;Baldo, Caroline Floreoto;Celotto, Andréa Carla;Batalh?o, Marcelo Eduardo;Cárnio, Evelin Capellari;Rodrigues, Alfredo José;Evora, Paulo Roberto Barbosa;
Arquivos Brasileiros de Endocrinologia & Metabologia , 2010, DOI: 10.1590/S0004-27302010000600004
Abstract: objectives: to verify if an experimental model of alloxan-diabetic rats promotes oxidative stress, reduces nitric oxide bioavailability and causes vascular dysfunction, and to evaluate the effect of n-acetylcysteine (nac) on these parameters. methods: alloxan-diabetic rats were treated or not with nac for four weeks. plasmatic levels of malondialdehyde (mda) and nitrite/nitrate (nox), the endothelial and inducible nitric oxide synthase (enos and inos) immunostaining and the vascular reactivity of aorta were compared among diabetic (d), treated diabetic (td) and control (c) rats. results: mda levels increased in d and td. nox levels did not differ among groups. endothelial enos immunostaining reduced and adventitial inos increased in d and td. the responsiveness of rings to acetylcholine, sodium nitroprusside, and phenylephrine did not differ among groups. conclusions: nac had no effect on the evaluated parameters and this experimental model did not promote vascular dysfunction despite the development of oxidative stress.
Evaluation of the in vitro antimicrobial activity of crude extracts of three Miconia species
Celotto, Andréa Carla;Nazario, Daniela Zaupa;Spessoto, Marcela de Almeida;Martins, Carlos Henrique Gomes;Cunha, Wilson Roberto;
Brazilian Journal of Microbiology , 2003, DOI: 10.1590/S1517-83822003000400010
Abstract: the antimicrobial activity of nine crude extracts of three miconia species (m. albicans, m. rubiginosa and m. stenostachya) was tested against eleven selected microorganisms: staphylococcus aureus, staphylococcus saprophyticus, proteus mirabilis, escherichia coli, enterococcus faecalis, shigella flexneri, klebsiella pneumoniae, salmonella sp, pseudomonas aeruginosa, streptococcus agalactiae and candida albicans. the results of the test showed that three extracts had some antimicrobial activity by well diffusion method. the ethanol extracts of miconia albicans and miconia rubiginosa were the most active.
Effects of acid-base imbalance on vascular reactivity
Celotto, A.C.;Capellini, V.K.;Baldo, C.F.;Dalio, M.B.;Rodrigues, A.J.;Evora, P.R.B.;
Brazilian Journal of Medical and Biological Research , 2008, DOI: 10.1590/S0100-879X2008005000026
Abstract: acid-base homeostasis maintains systemic arterial ph within a narrow range. whereas the normal range of ph for clinical laboratories is 7.35-7.45, in vivo ph is maintained within a much narrower range. in clinical and experimental settings, blood ph can vary in response to respiratory or renal impairment. this altered ph promotes changes in vascular smooth muscle tone with impact on circulation and blood pressure control. changes in ph can be divided into those occurring in the extracellular space (pho) and those occurring within the intracellular space (phi), although, extracellular and intracellular compartments influence each other. consistent with the multiple events involved in the changes in tone produced by altered pho, including type of vascular bed, several factors and mechanisms, in addition to hydrogen ion concentration, have been suggested to be involved. the scientific literature has many reports concerning acid-base balance and endothelium function, but these concepts are not clear about acid-base disorders and their relations with the three known mechanisms of endothelium-dependent vascular reactivity: nitric oxide (no/cgmp-dependent), prostacyclin (pgi2/camp-dependent) and hyperpolarization. during the last decades, many studies have been published and have given rise to confronting data on acid-base disorder and endothelial function. therefore, the main proposal of this review is to provide a critical analysis of the state of art and incentivate researchers to develop more studies about these issues.
A new method for the experimental study of fatigue behaviour of thermoplastic materials
M. Basso,A. Crevatin,M. Celotto,M. Sanità
Frattura ed Integrità Strutturale , 2008,
Abstract: Nowadays most industrial realities undergo a strong push to improve cost-effectiveness, productivity and quality of manufactured products. In particular we focussed our attention in the area of design of plastic structural components, including both optimization of existing structures and design of new ones. In this case, but the following considerations have a more general value, these needs could be translated into demanding requirements of cost-effectiveness, weight reduction, reduced time-to-market with guarantee reliability. From a material perspective this means demanding mechanical performances, attention to safety margins and need of a better control of key design parameters. To obtain these results, we need to develop a new approach and effective tools in the design of plastic materials and components aimed at tailoring part behaviour to endurance and performance requirements.The target of the project is to find effective tools for predicting life endurance and damage evolution of plastic materials and components under mechanical/thermal service loading, in order to support the development of new material formulations and the design and optimization of structural components. In a particular way, we focussed our work in the characterization and modellization of materials durability and damage mechanisms.One of the main problems related to materials durability is due to fatigue failure. Fatigue process is a progressive weakening of a component with increasing time under load such that loads to be supported satisfactorily for short duration produce failure after long durations [1, 2, 3]. Fatigue failure should not be thought only as the breaking of the specimen into two separated pieces, but as a progressive material damage accumulation [2]. Material damage during fatigue loading manifests as progressive reduction of stiffness and as creep [5].As standard fatigue testing are expensive in terms of money and time, it is essential to develop new approaches less time consuming and simpler to be implemented. One of the most important goals of the present work is the setting of an investigation method (Accelerated Fatigue Test) very simple to be implemented that is able to differentiate damage accumulation and durability performances of various material formulations in reduced time.
Onset of the ridge structure in AA, pA and pp collisions
C. Andrés,A. Moscoso,C. Pajares
Physics , 2014, DOI: 10.1103/PhysRevC.90.054902
Abstract: It is shown that the anomalous sharp increasing of the strength of the near-side ridge structures observed in Au-Au collisions at $\sqrt{s}=$ 62 GeV and $\sqrt{s}=$ 200 GeV and the onset of the ridge structure in pPb and in pp collisions can be naturally explained in the framework of string percolation. In all the cases the near-side strength reflects the collision area covered by the strings stretched between the colliding objects and therefore it is related to the shape of their profile functions. The dependence of the pseudorapidty and azimuthal widths on multiplicty and energy is qualitatively explained.
Universal geometrical scaling for hadronic interactions
C. Andrés,A. Moscoso,C. Pajares
Physics , 2012, DOI: 10.1016/j.nuclphysa.2013.02.013
Abstract: It is shown that defining a suitable saturation momentum $Q_s$, the $p_T$ distributions of pp and AA collisions for any centrality and energy depend only on $\tau=p^2_T/Q_s^2$ for $p_T1$, the higher the energy or the larger the size of the participant nuclei, the larger suppression present the respective spectra. The integrated spectrum gives a fraction of the hard multiplicity in the range from 9% for pp at 0.9 TeV to 2% for Pb-Pb central collisions at 2.76 TeV.
La"legge" europea e il nuovo sistema delle fonti nel Progetto di Costituzione europea
CELOTTO, Alfonso;
Boletín mexicano de derecho comparado , 2004,
Abstract: the system of sources of communitary law, in the context of the european union, has been traditionally criticized because of the so-called democratic deficit, due to the scarce participation that representatives of european citizens have had in the creation of rulings and directives. however, the author argues that the european union does not reproduce (nor can it reproduce) the national democratic model. because of this, to explain and to analyze the sources of law of communitary law and its relation to national systems, new legal categories are required. this is precisely the goal of the essay, which focuses on the examination of three concepts: "constitutional treaty", "european law", and "european frame law".
Legitimidad constitucional y legitimidad comunitaria: el control de constitucionalidad en Italia: un sistema mixto ?
Alfonso Celotto
Pensamiento Constitucional , 2003,
Abstract: No presenta resumen.
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