1,721,200 research outputs found
Experimental investigations of the synergistic-sedative effect of passiflora and kava
No full textIn order to investigate experimentally possible synergism between a passiflora extract and a kava extract, both were tested individually and in combination in a controlled pharmacological study in the mouse. The effects on amphetamine-induced hypermotility and on barbiturate-sleeping-time were studied. The results show that both drugs exert statistically significant sedative effects. Their nature differed with each single extract. While the sedative effect of kava manifested itself as a pronounced reduction in amphetamine-induced hypermotility relatively greater than that of passiflora, the reverse was the case for prolongation of barbiturate-sleeping-time which was greater with passiflora than kava. Synergism between the two drugs was observed when the two extracts were administered simultaneously
Endothelium, arachidonic acid, and coronary vascular tone
No full textVasoactive mediators play an important role in the control of coronary vascular tone. Arachidonic acid (AA) metabolites and endothelium-derived vasoactive factors have been implicated in coronary vasoregulation. AA can be metabolized via three separate routes in blood vessels, mediated by cyclooxygenase, lipoxygenase, and cytochrome P-450-dependent monooxygenase enzymes. AA can evoke endothelium-dependent relaxations that are due in part to the formation of cytochrome P-450-dependent metabolites, inasmuch as drugs that modify cytochrome P-450 activity produce parallel changes in endothelium-dependent relaxations to AA. Moreover, some cytochrome P-450-derived metabolites formed biologically cause relaxations of isolated blood vessels. A cytochrome P-450-dependent pathway does not appear to contribute to endothelium-dependent relaxations induced by acetylcholine, which suggests that there may be a number of endothelium-derived relaxing factors (EDRFs). In addition, two endothelium-derived contractile factors have been described, including an unidentified cyclooxygenase metabolite of AA and a polypeptide isolated from cultured cells. As both prostaglandin I2 and acetylcholine-induced EDRF also inhibit platelet aggregation, endothelial injury and loss of these factors may predispose to vasospasm precipitated by release of platelet-derived mediators such as thromboxane A2 (TXA2) and 5-hydroxytryptamine. Unstable angina may be a clinical syndrome in which these events occur, which can be alleviated by inhibition of platelet activation and TXA2 formation with aspirin. Attenuation of endothelium-dependent relaxations can also occur without loss of endothelial cells. Neutrophil-endothelium interactions, precipitated by an ischemic episode, may initiate endothelial dysfunction and underlie the development of vasospasm in some conditions. Whether increased production of endothelium-derived contractile factors also occurs in vasospastic conditions remains to be determined
Flavonoids, leukocyte migration and eicosanoids
No full textQuercetin reduced the concentration of prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) in the pleural exudate induced in rats by 1% carrageenan given intrapleurally. Leucocyte migration in the exudate was also reduced by the flavonoid. Inhibition of eicosanoids and leucocytes in the exudate was dose-related. Quercetin also reduced LTB4 synthesis in cells stimulated with ionophore A23187, either ex-vivo or in-vitro. a similar, though less active, mode of action was found with quercitrin, while apigenin and luteolin reduced leucocyte accumulation and PGE2 formation, but not LTB4-formation
EFFECT OF ADENOSINE ON ISOPROTERENOL-INDUCED HYPERTROPHY IN VITRO. A PRELIMINARY STUDY
Full text linkPersistent β1-adrenergic stimulation is thought to induce cardiac hypertrophy, alteration in calcium regulation and Cx43 over-expression. Adenosine is a negative feedback inhibitor of adrenergic
stimulation in the heart, protecting it from toxic effects of overstimulation.
The aim of our study evaluate the effects of adenosine administration on Cx43 and pCx43 expression and [Ca2+]i in Isoproterenol-treatedcardiomiocytesby usingH9c2 cells.
Adenosine co-treatment reduced cellular hypertrophy, Cx43, pCx43 and CaMKII over-expression, and
reducedintracellularCa2+ overload.
These results suggest that the beneficial activity of adenosine on cardiomyocytes underlie the reduction
of Cx43-dependent calcium overload and CaMKII over-expression, implying a potential therapeutic in cardiac hypertrophy
The adenosinergic system in cancer: Key therapeutic target
No full textHigh amounts of adenosine are released in the tumor mass. Depending on the levels of adenosine, as well as on the receptor subtypes that are expressed by immune cells, adenosine can affect tumor growth in different fashions. Specifically targeting CD73, the rate-limiting enzyme for the extracellular generation of adenosine, or the A3 receptor offers new therapeutic strategies to limit tumor progression
Experimental animal studies on the hypoglycemic effects of a Copalchi extract.
No full textThe hypoglycemic effect of a Copalchi extract (Sucontral) was tested in 60 adult-male and female-Wistar rats in the present randomized, placebo-controlled, parallel-comparative animal study. A control group receiving only an Altromin standard chow was compared to treatment groups which received an Altromin chow enriched with Copalchi dry substance at 0.028% m/m or at 0.28% m/m. The study period was 30 days. The distinctly significant blood glucose lowering effect of the Copalchi extract could be demonstrated in both treatment groups. No significant difference in the antidiabetic effect was seen between the two concentrations. The onset of action of the Copalchi extract was observed between treatment day 1 and 3. A 20-25% decrease in the blood glucose concentration was achieved between the 7th and 15th day of treatment and remained at this level thereafter. This plateau was reached in the female rats already between treatment day 3 and 5. The parallel observed increase in the mean body weight was not striking and generally was the same between the test animals and the control animals
Role of plasmacytoid dendritic cells in lung-associated inflammation.
No full textPlasmacytoid Dendritic Cells (pDCs) are important immune orchestrators. One of the most important features of pDCs is the high production of IFN type I that can promote the polarization of T cells towards a Th1 phenotype. Recent evidence has highlighted the relevance of pDCs in therapy for asthma, lung infections and cancer. However, it is to note that pDCs can also participate in suppressive networks via the recruitment of T regulatory cells. Further studies are needed to understand pDCs activity in the lung, not only to elucidate pathological mechanisms, but also to lead towards new therapeutic approaches for lung inflammatory-based diseases. The article also outlines recent patents on plasmacytoid DCs
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