994 resultados para alfa-2-agonists
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El objetivo de este estudio es establecer si la dexmedetomidina (DEX) es segura y efectiva para el manejo coadyuvante de síndrome de abstinencia a alcohol (SAA) a través de la búsqueda de evidencia científica. Metodología: se realiza una revisión sistemática de literatura publicada y no publicada desde enero de 1989 hasta febrero 2016 en PubMed, Embase, Scopus, Bireme, Cochrane library y en otras bases de datos y portales. Los criterios de inclusión fueron ensayos clínicos aleatorizados y no aleatorizados, estudios cuasi-experimentales, estudios de cohorte, y estudios de casos y controles; que incluyeron pacientes mayores de 18 años hospitalizados con diagnóstico de SAA y donde se usó DEX como terapia coadyuvante. Resultados: 7 estudios, 477 pacientes, se incluyeron en el análisis final. Se encontraron dos ensayos clínicos aleatorizados, tres estudios de casos y controles y dos estudios de cohorte retrospectivo. Solo uno de los estudios fue doble ciego y utilizó placebo como comparador. Análisis y conclusiones: en los estudios experimentales se determinan que el uso de DEX como terapia coadyuvante en el manejo de SAA tiene significancia clínica y estadística para disminuir dosis de BZD en las primeras 24 horas de tratamiento; pero no demostraron tener otros beneficios clínicos. En los estudios no aleatorizados existe consenso que relaciona el uso de DEX con menores dosis de BZD de forma temprana. Recomendaciones: no se recomienda el uso de DEX en SAA de forma rutinaria. Se recomienda usar DEX solo en casos en el que exista evidencia fallo terapéutico a BZD.
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The role of beta(3)- and other putative atypical beta-adrenaceptors in human white adipocytes and right atrial appendage has been investigated using CGP 12177 and novel phenylethanolamine and aryloxypropanolamine beta(3)-adrenoceptor (beta(3)AR) agonists with varying intrinsic activities and selectivities for human cloned PAR subtypes. The ability to demonstrate beta(1/2)AR antagonist-insensitive (beta(3) or other atypical beta AR-mediated) responses to CGP 12177 was critically dependent on the albumin batch used to prepare and incubate the adipocytes. Four aryloxypropanolamine selective beta(3)AR agonists (SB-226552, SB-229432, SB-236923, SB-246982) consistently elicited beta(1/2)AR antagonist-insensitive lipolysis. However, a phenylethanolamine (SB-220646) that was a selective full beta(3)AR agonist elicited full lipolytic and inotropic responses that were sensitive to beta(1/2)AR antagonism, despite it having very low efficacies at cloned beta(1)- and beta(2)ARs. A component of the response to another phenylethanolamine selective beta(3)AR agonist (SB-215691) was insensitive to beta(1/2)AR antagonism in some experiments. Because novel aryloxypropanolamine had a beta(1/2)AR antagonist-insensitive inotropic effect, these results establish more firmly that beta(3)ARs mediate lipolysis in human white adipocytes, and suggest that putative 'beta(4)ARs' mediate inotropic responses to CGP 12177. The results also illustrate the difficulty of predicting from studies on cloned beta ARs which beta ARs will mediate responses to agonists in tissues that have a high number of beta(1)- and beta(2)ARs or a low number of beta(3)ARs.
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Live attenuated vaccines have recently been introduced for preventing rotavirus disease in children. However, alternative strategies for prevention and treatment of rotavirus infection are needed mainly in developing countries where low vaccine coverage occurs. In the present work, N-acetylcysteine (NAC), ascorbic acid (AA), some nonsteroidal anti-inflammatory drugs (NSAIDs) and peroxisome proliferator-activated receptor gamma (PPARγ) agonists were tested for their ability to interfere with rotavirus ECwt infectivity as detected by the percentage of viral antigen-positive cells of small intestinal villi isolated from ECwt-infected ICR mice. Administration of 6 mg NAC/kg every 8 h for three days following the first diarrhoeal episode reduced viral infectivity by about 90%. Administration of AA, ibuprofen, diclofenac, pioglitazone or rosiglitazone decreased viral infectivity by about 55%, 90%, 35%, 32% and 25%, respectively. ECwt infection of mice increased expression of cyclooxygenase-2, ERp57, Hsc70, NF-κB, Hsp70, protein disulphide isomerase (PDI) and PPARγ in intestinal villus cells. NAC treatment of ECwt-infected mice reduced Hsc70 and PDI expression to levels similar to those observed in villi from uninfected control mice. The present results suggest that the drugs tested in the present work could be assayed in preventing or treating rotaviral diarrhoea in children and young animals.
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alpha-Bromoacetophenones are important in organic synthesis. They have been widely used as precursors of several natural products. Several methods of bromination aiming at their synthesis have been described, however they furnish a mixture of starting material 10, mono 8 and dibromide 11 products. We developed a novel, simple and efficient synthesis of these compounds with applications in the synthesis of benzoylbenzofurans 9, compounds with important pharmacological properties, such as the ability of dilating the coronary artery and analgesic action. Such compounds have also been used as key intermediates to obtain quinone systems.
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Background and purpose: Low efficacy partial agonists at the D-2 dopamine receptor may be useful for treating schizophrenia. In this report we describe a method for assessing the efficacy of these compounds based on stimulation of [S-35]GTP gamma S binding. Experimental approach: Agonist efficacy was assessed from [S-35]GTP gamma S binding to membranes of CHO cells expressing D2 dopamine receptors in buffers with and without Na+. Effects of Na+ on receptor/G protein coupling were assessed using agonist/[H-3] spiperone competition binding assays. Key results: When [S-35]GTP gamma S binding assays were performed in buffers containing Na+, some agonists (aripiprazole, AJ-76, UH-232) exhibited very low efficacy whereas other agonists exhibited measurable efficacy. When Na+ was substituted by N-methyl D-glucamine, the efficacy of all agonists increased (relative to that of dopamine) but particularly for aripiprazole, aplindore, AJ-76, (-)-3-PPP and UH-232. In ligand binding assays, substitution of Na+ by N-methyl D-glucamine increased receptor/G protein coupling for some agonists -. aplindore, dopamine and (-)-3-PPP-but for aripiprazole, AJ-76 and UH-232 there was little effect on receptor/G protein coupling. Conclusions and implications: Substitution of Na+ by NMDG increases sensitivity in [S-35] GTPgS binding assays so that very low efficacy agonists were detected clearly. For some agonists the effect seems to be mediated via enhanced receptor/G protein coupling whereas for others the effect is mediated at another point in the G protein activation cycle. AJ-76, aripiprazole and UH-232 seem particularly sensitive to this change in assay conditions. This work provides a new method to discover these very low efficacy agonists.
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Cholecystitis is one of the most common gastrointestinal diseases. Inflammation induces the activation of proteases that can signal to cells by cleaving protease-activated receptors (PARs) to induce hemostasis, inflammation, pain, and repair. However, the distribution of PARs in the gallbladder is unknown, and their effects on gallbladder function have not been fully investigated. We localized immunoreactive PAR(1) and PAR(2) to the epithelium, muscle, and serosa of mouse gallbladder. mRNA transcripts corresponding to PAR(1) and PAR(2), but not PAR(4), were detected by RT-PCR and sequencing. Addition of thrombin and a PAR(1)-selective activating peptide (TFLLRN-NH(2)) to the serosal surface of mouse gallbladder mounted in an Ussing chamber stimulated an increase in short-circuit current in wild-type but not PAR(1) knockout mice. Similarly, serosally applied trypsin and PAR(2) activating peptide (SLIGRL-NH(2)) increased short-circuit current in wild-type but not PAR(2) knockout mice. Proteases and activating peptides strongly inhibited electrogenic responses to subsequent stimulation with the same agonist, indicating homologous desensitization. Removal of HCO(3)(-) ions from the serosal buffer reduced responses to thrombin and trypsin by >80%. Agonists of PAR(1) and PAR(2) increase intracellular Ca(2+) concentration in isolated and cultured gallbladder epithelial cells. The COX-2 inhibitor meloxicam and an inhibitor of CFTR prevented the stimulatory effect of PAR(1) but not PAR(2). Thus PAR(1) and PAR(2) are expressed in the epithelium of the mouse gallbladder, and serosally applied proteases cause a HCO(3)(-) secretion. The effects of PAR(1) but not PAR(2) depend on generation of prostaglandins and activation of CFTR. These mechanisms may markedly influence fluid and electrolyte secretion of the inflamed gallbladder when multiple proteases are generated.
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Trypsin and mast cell tryptase cleave proteinase-activated receptor 2 and, by unknown mechanisms, induce widespread inflammation. We found that a large proportion of primary spinal afferent neurons, which express proteinase-activated receptor 2, also contain the proinflammatory neuropeptides calcitonin gene-related peptide and substance P. Trypsin and tryptase directly signal to neurons to stimulate release of these neuropeptides, which mediate inflammatory edema induced by agonists of proteinase-activated receptor 2. This new mechanism of protease-induced neurogenic inflammation may contribute to the proinflammatory effects of mast cells in human disease. Thus, tryptase inhibitors and antagonists of proteinase-activated receptor 2 may be useful anti-inflammatory agents.
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Purpose: the objective of the present investigation was to determine implantation and pregnancy rates in patients undergoing ICSI and treated with beta(2)-adrenergic agonists, considering the uterine-relaxing action of these agents.Methods: A total of 225 women undergoing ICSI at the Center for Human Reproduction, Sinha Junqueira Maternity Foundation, entered the study. Patient participation in each group was random, by drawing lots, using a randomization table previously elaborated for the study (2:2:1). The group I (90 women) received 10 mg of terbutaline daily for 15 days starting on the day of oocyte retrieval; group II (90 women) received 20 mg of ritodrine daily during the same period of time as group I; group III (45 patients) received no treatment and was used as control. The evaluation was interrupted in 3 patients of group I and in 30 patients of group II because of a high incidence of side effects.Results: Pregnancy, implantation, and miscarriage rates were not significantly different (p>0.05) between the three groups: 29.88%, 13.25%, and 26.9% for group I; 33.33%, 17.5%, and 10.0% for group II; 28.88%, 15.07%, and 15.38% for group III, respectively.Conclusions: the results of this study do not support the routine use of beta(2)-adrenergic agonists during the peri-implantation period in assisted reproductive technology cycles.
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The effects of sodium and potassium excretion after intrahypothalamic administration of two α-adrenoceptor agonists and the effect of α-adrenoceptor antagonists were studied in groups of rats. Prazosin was equally effective at blocking the natriuretic and kaliuretic responses to the α1-adrenoceptor agonist phenylephrine and the mixed α1/α2-adrenoceptor agonist noradrenaline, while yohimbine which acts preferentially on α2-adrenoceptors was effective in potentiating these responses. These results suggest the presence of two types of α-adrenoceptors for the modulation of ventromedial hypothalamic pathways that interfere with the regulation of the two cations: stimulation of α1-adrenoceptors facilitates, while stimulation of α2-adrenoceptors inhibits the excretion of the ions.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The role of innate immune response in protection against leptospirosis is poorly understood. We examined the expression of the chemokine CXCL2/MIP-2 and the cytokine TNF-alpha. in experimental resistant and susceptible mice models, C3H/HeJ, C3H/HePas and BALB/c strains, using a virulent strain of Leptospira interrogans serovar Copenhageni. Animals were infected intraperitoneally with 107 cells and the development of the disease was followed. Mortality of C3H/HeJ mice was observed whereas C3H/HePas presented jaundice and BALB/c mice remained asymptomatic. The infection was confirmed by the presence of leptospiral DNA in the organs of the animals, demonstrated by PCR. Sections of the organs were analyzed, after H&E stain. The relative expression of mRNA of chemokine CXCL2/MIP-2 and cytokine TNF-alpha was measured in lung, kidney and liver of the mice by qPCR. The concentrations of these proteins were measured in extracts of tissues and in serum of the animals, by ELISA. Increasing levels of transcripts and protein CXCL2/MIP-2 were detected since the first day of infection. The highest expression was observed at third day of infection in kidney, liver and lung of BALB/c mice. In C3H/HeJ the expression of CXCL2/MIP-2 was delayed, showing highest protein concentration in lung and kidney at the 5th day. Increasing in TNF-alpha transcripts were detected after infection, in kidney and liver of animals from the three mice strains. The expression of TNF-alpha protein in C3H/HeJ was also delayed, being detected in kidney and lung. Our data demonstrated that Leptospira infection stimulates early expression of CXCL2/MIP-2 and TNF-alpha in the resistant strain of mice. Histological analysis suggests that the expression of those molecules may be related to the influx of distinct immune cells and plays a role in the naturally acquired protective immunity. (C) 2012 Elsevier Ltd. All rights reserved.
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We evaluate the immunomodulation of Peroxisome proliferator-activated receptor-gamma (PPAR-gamma) agonists 15d-PGJ(2) and rosiglitazone (RGZ) in a model of chronic eosinophilia. 15d-PGJ(2) and RGZ significantly reduce eosinophil migration into the peritoneal cavity and down-regulate the eosinopoiesis. The synthesis of IL-5 was decreased after the treatment with 15d-PGJ(2) and RGZ corroborating with the eosinophil migration inhibition. However, IgE was decreased only after the administration of 15d-PGJ(2) in part due to B-cell inhibition. We also observed a decrease in the synthesis of IL-33, IL-17 and IL-23, suggesting that besides the modulation of Th2 pattern, there is a modulation via IL-23 and IL-17 suggesting a role of these cytokines in the eosinophil recruitment. In fact IL-17(-1-) mice failed to develop an eosinophilic response. Altogether, the results showed that PPAR-gamma agonists mainly 15d-PGJ(2), have therapeutic efficacy in eosinophil-induced diseases with an alternative mechanism of control, via IL-23/IL-17 and IL-33. (C) 2011 Elsevier Inc. All rights reserved.
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The cannabinoid CB(2) receptor is known to modulate osteoclast function by poorly understood mechanisms. Here, we report that the natural biphenyl neolignan 4'-O-methylhonokiol (MH) is a CB(2) receptor-selective antiosteoclastogenic lead structure (K(i) < 50 nM). Intriguingly, MH triggers a simultaneous G(i) inverse agonist response and a strong CB(2) receptor-dependent increase in intracellular calcium. The most active inverse agonists from a library of MH derivatives inhibited osteoclastogenesis in RANK ligand-stimulated RAW264.7 cells and primary human macrophages. Moreover, these ligands potently inhibited the osteoclastogenic action of endocannabinoids. Our data show that CB(2) receptor-mediated cAMP formation, but not intracellular calcium, is crucially involved in the regulation of osteoclastogenesis, primarily by inhibiting macrophage chemotaxis and TNF-α expression. MH is an easily accessible CB(2) receptor-selective scaffold that exhibits a novel type of functional heterogeneity.