111 resultados para CHANNEL CONSTITUENTS
em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Este estudo objetivou avaliar o comportamento dos componentes do sangue em cavalos que concluiram com êxito provas de enduro em condições tropicais. Punção da veia jugular foi realizada para coletar o sangue antes, durante e após o evento. Os dados foram analisados por meio de uma abordagem matemática, com base no hematócrito e volume de sangue onde a variação percentual no volume plasmático foi utilizada para corrigir os valores de cada variável analisada. O nível de significância adotado foi P<0,05. O modelo matemático proposto para avaliar as concentrações de componentes do sangue permitiu a observação de um padrão diferente no comportamento de várias variáveis plasmáticas, destacando que a abordagem seguida pelos autores é mais sensível do que aquelas que não seguiram este procedimento. em conclusão, o método utilizado neste estudo permitiu acompanhar os processos fisiológicos que realmente ocorrem durante o esforço de resistência em condições tropicais.
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The reference intervals for biochemical variables and red blood cell indices of healthy intensively bred channel catfish Ictalurus punctatus were determined. The blood variables were determined using standardized clinical methods. The reference intervals (25th and 75th percentiles) were established using a non-parametric method. Reference intervals for plasma glucose, serum total protein, sodium, potassium, calcium, magnesium, chloride concentration, primary and secondary red blood cell indices were established. The haematological and biochemical reference intervals established may allow important clinical decisions about channel catfish. (c) 2007 the Authors Journal compilation (C) 2007 the Fisheries Society of the British Isles.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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CHEMICAL CONSTITUENTS and ANTIOXIDANT ACTIVITY FROM LEAVES EXTRACTS of Terminalia fagifolia Mart. et Zucc. Phytochemical investigation of ethanolic leaves extracts of T. fagifolia led to the isolation of (+)-catechin, sitosterol-3-O-beta-D-glucopyranoside, alpha- and beta-tocopherol, a mixture of lupeol, alpha- and beta-amyrin, sitosterol and a mixture of glicosid flavonoids (CP-13). The structures of these compounds were identified by (1)H and (13)C NMR spectral analysis and comparison with literature data. Absolute configuration of the catechin was determinate by circular dichroism. Antioxidant activity (EC(50)), evaluated by 2,2-diphenyl-1-picrylhidrazyl (DPPH) assay system, decreased in the order: (+)-catechin > hydroalcoholic fraction > CP-13 > aqueous fraction > EtOH extract.
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We have shown that myocardial dysfunction induced by food restriction is related to calcium handling. Although cardiac function is depressed in food-restricted animals, there is limited information about the molecular mechanisms that lead to this abnormality. The present study evaluated the effects of food restriction on calcium cycling, focusing on sarcoplasmic Ca2+-ATPase (SERCA2), phospholamban (PLB), and ryanodine channel (RYR2) mRNA expressions in rat myocardium. Male Wistar-Kyoto rats, 60 days old, were submitted to ad libitum feeding (control rats) or 50% diet restriction for 90 days. The levels of left ventricle SERCA2, PLB, and RYR2 were measured using semi-quantitative RT-PCR. Body and ventricular weights were reduced in 50% food-restricted animals. RYR2 mRNA was significantly decreased in the left ventricle of the food-restricted group (control = 5.92 +/- 0.48 vs food-restricted group = 4.84 +/- 0.33, P < 0.01). The levels of SERCA2 and PLB mRNA were similar between groups (control = 8.38 +/- 0.44 vs food-restricted group = 7.96 +/- 0.45, and control = 1.52 +/- 0.06 vs food-restricted group = 1.53 +/- 0.10, respectively). Down-regulation of RYR2 mRNA expressions suggests that chronic food restriction promotes abnormalities in sarcoplasmic reticulum Ca2+ release.
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Obesity has been shown to impair myocardial performance. Nevertheless, the mechanisms underlying the participation of calcium (Ca2+) handling on cardiac dysfunction in obesity models remain unknown. L-type Ca2+ channels and sarcoplasmic reticulum (SR) Ca2+-ATPase (SERCA2a), may contribute to the cardiac dysfunction induced by obesity. The purpose of this study was to investigate whether myocardial dysfunction in obese rats is related to decreased activity and/or expression of L-type Ca2+ channels and SERCA2a. Male 30-day-old Wistar rats were fed standard (C) and alternately four palatable high-fat diets (Ob) for 15 weeks. Obesity was determined by adiposity index and comorbidities were evaluated. Myocardial function was evaluated in isolated left ventricle papillary muscles under basal conditions and after inotropic and lusitropic maneuvers. L-type Ca2+ channels and SERCA2a activity were determined using specific blockers, while changes in the amount of channels were evaluated by Western blot analysis. Phospholamban (PLB) protein expression and the SERCA2a/PLB ratio were also determined. Compared with C rats, the Ob rats had increased body fat, adiposity index and several comorbidities. The Ob muscles developed similar baseline data, but myocardial responsiveness to post-rest contraction stimulus and increased extracellular Ca2+ was compromised. The diltiazem promoted higher inhibition on developed tension in obese rats. In addition, there were no changes in the L-type Ca2+ channel protein content and SERCA2a behavior (activity and expression). In conclusion, the myocardial dysfunction caused by obesity is related to L-type Ca2+ channel activity impairment without significant changes in SERCA2a expression and function as well as L-type Ca2+ protein levels. J. Cell. Physiol. 226: 2934-2942, 2011. (C) 2011 Wiley-Liss, Inc.
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Alchornea glandulosa (Euphorbiaceae) is a plant used in folk medicine as an antiulcer agent. Rats pretreated with methanolic extract obtained from the leaves of A. glandulosa (AG) showed a dose-dependent effect and significant reduction of gastric ulcers induced by absolute ethanol at the doses of 500 (57%) and 1000 mg/kg (35%) in relation to the control group. Pretreatment of mice with AG (500, 1000 mg/kg, p.o.) showed dose-dependent activity and significantly decreased the severity of lesions caused by HCl/ethanol and by non steroidal anti inflammatory drug-induced gastric lesions. Pretreatment with AG also induced antisecretory action via local and systemic routes and a significant decrease in the total gastric acid content. The gastroprotective effects of AG involved the participation of nitric oxide and increased levels of endogenous sulfhydryl compounds, which are defensive mechanisms of the gastrointestinal mucosa against aggressive factors. The ability of AG to heal gastric ulcers was evaluated after 14 consecutive days of treatment. The results showed that single oral administrations of AG (250 mg/kg/once daily) potently stimulates gastric epithelial cell proliferation that contributes to the accelerated healing of gastric ulcers induced by acetic acid. In addition, no subacute toxicity (body weight gain, vital organs, and serum biochemical parameters) was observed during treatment with AG. Phytochemical investigation of AG led to the isolation of myricetin-3-O-alpha-L-rhamnopyranoside, quercetin-3-O-alpha-L-arabinopyranoside, quercetin-3-O-beta-D-galactopyranoside, quercetin, amentoflavone, methyl gallate, gallic acid, and pterogynidine. We also established the phytochemical profile of AG with the quantification of total phenolic compounds. These compounds may contribute to the observed antiulcerogenic effects of AG.
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We study the voltage dependent calcium channels and nitric oxide involvement in angiotensin II-induced pressor effect. The antipressor action of L-Type calcium channel antagonist, nifedipine, has been studied when it was injected into the third ventricle prior to angiotensin II. The influence of nitric oxide on nifedipine antipressor action has also been studied by utilizing N(W)-nitro-L-arginine methyl ester (LNAME) (40 mu g/0.2 mu l) a nitric oxide synthase inhibitor and L-arginine ( 20 mu g/0.2 mu l), a nitric oxide donor agent. Adult male Holtzman rats weighting 200-250 g, with cannulae implanted into the third ventricle were injected with angiotensin II. Angiotensin II produced an elevation in mean arterial pressure and a decreased in heart rate. Such effects were potentiated by the prior injection of LNAME. L-arginine and nifedipine blocked the effects of angiotensin II. These data showed the involvement of L-Type calcium channel and a free radical gas nitric oxide in the central control of angiotensin II-induced pressor effect. This suggested that L-Type calcium channel of the circunventricular structures of central nervous system participated in both short and long term neuronal actions of ANG II with the influence of nitrergic system.
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We present a numerical solution for the steady 2D Navier-Stokes equations using a fourth order compact-type method. The geometry of the problem is a constricted symmetric channel, where the boundary can be varied, via a parameter, from a smooth constriction to one possessing a very sharp but smooth corner allowing us to analyse the behaviour of the errors when the solution is smooth or near singular. The set of non-linear equations is solved by the Newton method. Results have been obtained for Reynolds number up to 500. Estimates of the errors incurred have shown that the results are accurate and better than those of the corresponding second order method. (C) 2002 Elsevier B.V. All rights reserved.
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The anti-allergic active fractionation of hexane extracts of the leaves and stems of Anchietia salutaris,ar. martiana (family Violaceae) nas performed by monitoring their activities with an in vitro bioassay system measuring the inhibitory effects on induced histamine release from guinea pig lung cells. Three known pentacyclic triterpenes (friedelin, alpha-amyrin, beta-amyrin) were isolated, but these compounds were inactive. Aliphatic hydrocarbons and methyl esters of fatty acids (palmitic, oleic, linoleic, linolenic acids) were detected in active fractions. All compounds isolated were detected for the first time in this medicinal plant.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Introduction. Premature ejaculation is one of the most common male sexual dysfunctions. Current pharmacological treatments involve reduction in penile sensitivity by local anesthetics or increase of ejaculatory threshold by selective serotonin reuptake inhibitors. a1-Adrenoceptors (a1-ARs) and L-type calcium channels are expressed in the smooth muscles of the male reproductive tract, and their activations play an important role in the physiological events involved in the seminal emission phase of ejaculation.Aim. To evaluate if the inhibition of the contractility of the vas deferens and seminal vesicle by alpha(1)-AR antagonism or the L-type calcium channel blockade can delay ejaculation.Methods. The effects of the alpha(1)-AR antagonist tamsulosin and of the L-type calcium channel blockers, nifedipine and (S)-(+)-niguldipine, on contractions induced by norepinephrine in the rat vas deferens and seminal vesicles in vitro and on the ejaculation latency of male rats in behavioral mating tests were evaluated.Main Outcome Measure. Tension development of vas deferens and seminal vesicles in response to norepinephrine in vitro and behavioral mating parameters were quantified.Results. Tension development of vas deferens and seminal vesicle to alpha(1)-AR activation was significantly inhibited by tamsulosin, nifedipine, and (S)-(+)-niguldipine. Tamsulosin displayed insurmountable antagonism of contractions induced by norepinephrine in the rat vas deferens and seminal vesicle. Ejaculation latency of male rats was not modified by tamsulosin, nifedipine, or (S)-(+)-niguldipine; however, both the number and weight of the seminal plugs recovered from female rats mated with male rats treated with tamsulosin were significantly reduced.Conclusion. Seminal emission impairment by inhibition of vas deferens or seminal vesicle contractility by L-type calcium channel blockade or alpha(1)-AR antagonism is not able to delay the ejaculation. de Almeida Kiguti LR and Pupo AS. Investigation of the effects of alpha(1)-adrenoceptor antagonism and L-type calcium channel blockade on ejaculation and vas deferens and seminal vesicle contractility in vitro. J Sex Med 2012; 9: 159-168.
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Objectives Propolis is a honeybee product used extensively in traditional medicine for its antioxidant, anti-inflammatory, immunomodulatory and anticancer effects. Propolis exhibits a broad spectrum of biological activities because it is a complex mixture of natural substances. In this review, the antitumour effects of propolis extracts and its constituents (e. g. flavonoids, terpenes and caffeic acid phenethyl ester) are discussed.Key findings The effect of propolis on experimental carcinogenesis is discussed, as well as its possible mechanisms of action against tumours, involving apoptosis, cell cycle arrest and interference on metabolic pathways. Propolis seems to be efficient against different tumour cells both in vitro and in vivo, which suggests its potential in the development of new anticancer drugs.Summary Propolis extracts may be important economically and would allow a relatively inexpensive cancer treatment. Preclinical investigations are needed to further elucidate the benefits of propolis and its antitumour properties.
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The crustacean species composition in the intertidal zones of 13 sheltered unconsolidated marine beaches in south-eastern Brazil is described. Fifty-three crustacean species were collected, adding 46 species to the total reported by previous studies in the same region. Decapods dominated the community, in contrast to exposed sandy beaches where peracarids normally predominate. The species were distributed irregularly among the beaches. Richness varied markedly among sites, and was positively related to a combination of factors such as fine sand grains, high organic matter content, and relatively low silt-clay content. The presence of rock fragments enabled both rocky shore and sandy beach crustaceans to occur oil the same beaches. Richness and abundance of crustaceans showed no clear relationship to sediment grain size and slope, in contrast to the norm for exposed sandy beaches. The dominance of the tanaid Kalliapseudes schubarti in sonic areas may be a result of organic matter pollution in the region. These beaches showed higher species richness than typical sheltered and exposed sandy beaches, indicating that this sheltered, highly heterogeneous seascape is an important area for conservation.