RESUMO
Bee venom (BV)-a complex mixture of peptides and toxic proteins including phospholipase A2 and melittin-promotes blood clotting. In this study, we investigated the anti-atopic properties of BV and the mechanism associated with its regulation of the complement system. BV treatment upregulated the mRNA and protein levels of CD55 in THP-1 cells. Further experiments revealed that the phosphorylation of ERK was associated with upregulation of CD55. A complement-dependent cytotoxicity assay and a bacteria-killing assay showed that BV inactivated the complement system through the induction of CD55. The serum levels of C3 convertase (C3C) and Membrane attack complex (MAC) increased, while CD55 decreased in mice with AD-like lesions from DNCB treatment. However, the levels were inverted when the AD-like mice were treated with BV using subcutaneous injection, and we observed that the AD symptoms were alleviated. BV is often used to treat AD but its mechanism has not been elucidated. Here, we suggest that BV alleviates AD through the inactivation of the complement system, especially by the induction of CD55.
Assuntos
Anti-Inflamatórios/uso terapêutico , Venenos de Abelha/uso terapêutico , Antígenos CD55/metabolismo , Dermatite Atópica/tratamento farmacológico , Animais , Anti-Inflamatórios/farmacologia , Venenos de Abelha/farmacologia , Antígenos CD55/genética , Linhagem Celular , Convertases de Complemento C3-C5/metabolismo , Complexo de Ataque à Membrana do Sistema Complemento/metabolismo , Dermatite Atópica/genética , Dermatite Atópica/metabolismo , Escherichia coli/efeitos dos fármacos , Humanos , Masculino , Camundongos Endogâmicos BALB C , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Regulação para Cima/efeitos dos fármacosRESUMO
BACKGROUND: In a randomized, double-blind, prospective study, we investigated whether an intraoperative high versus low dose of remifentanil increased postoperative hyperalgesia and whether magnesium can prevent remifentanil-induced hyperalgesia. METHODS: Ninety patients undergoing thyroidectomy were randomly assigned to 1 of 3 groups. Remifentanil was intraoperatively infused at 0.05 µg/kg/min (group LO) or 0.2 µg/kg/min (groups HI and HM). Patients in group HM received MgSO(4) 30 mg/kg at induction followed by an intraoperative infusion of 10 mg/kg/h. Mechanical pain thresholds on the forearm and periincisional area were assessed by von Frey filament the evening before surgery and postoperatively at 24 and 48 hours. Pain measured on a verbal numerical rating scale (VNRS) (0-10) and additional analgesics were recorded in the postanesthesia care unit postoperatively at 6, 24, and 48 hours. RESULTS: There was a significantly greater decrease in pain threshold on the periincisional area at 24 and 48 hours postoperatively in group HI, as compared with the other 2 groups. The 95% confidence intervals for the mean difference in pain thresholds on the periincisional area at 24 and 48 hours postoperatively were 0.31 to 1.11 and 0.36 to 1.14 for group HI versus group LO, 0.45 to 1.26 and 0.54 to 1.32 for group HI versus group HM (values are log(10) of force in milligrams). The change in pain threshold on the forearm was similar among the groups. Group HI had significantly higher VNRS scores (median [interquartile range], 3 [2-4]) than group LO (2 [1-3] and group HM (2 [1-3]) at 48 hours postoperatively. The 95% confidence intervals for median difference in VNRS score at 48 hours postoperatively were 1 to 2 for group HI versus group LO and 0 to 2 for group HI versus group HM. There were no significant differences in the number of patients who requested rescue analgesics in the postoperative anesthesia care unit and general ward during 48 hours postoperatively among the 3 groups. CONCLUSIONS: A relatively high dose of intraoperative remifentanil enhances periincisional hyperalgesia. Intraoperative MgSO(4) prevents remifentanil-induced hyperalgesia. However, hyperalgesia did not reach clinical relevance in terms of postoperative pain or analgesic consumption in patients undergoing thyroidectomy.
Assuntos
Anestésicos Intravenosos/efeitos adversos , Hiperalgesia/prevenção & controle , Sulfato de Magnésio/uso terapêutico , Dor Pós-Operatória/prevenção & controle , Piperidinas/efeitos adversos , Tireoidectomia/efeitos adversos , Adulto , Idoso , Analgésicos/administração & dosagem , Período de Recuperação da Anestesia , Anestesia Geral , Anestésicos Intravenosos/administração & dosagem , Anestésicos Intravenosos/antagonistas & inibidores , Pressão Sanguínea/efeitos dos fármacos , Método Duplo-Cego , Feminino , Frequência Cardíaca/efeitos dos fármacos , Humanos , Sulfato de Magnésio/efeitos adversos , Masculino , Pessoa de Meia-Idade , Medição da Dor , Limiar da Dor/efeitos dos fármacos , Estimulação Física , Piperidinas/administração & dosagem , Piperidinas/antagonistas & inibidores , Sala de Recuperação , Remifentanil , Adulto JovemRESUMO
This study examined the synthesis of biodiesel using supercritical or subcritical methanol with metal oxide catalysts. The transesterification of rapeseed oil was carried out with the metal oxide catalysts (SrO, CaO, ZnO, TiO(2) and ZrO(2)) to determine the most effective heterogeneous catalyst having the highest catalytic activity with minimum weight loss caused by dissolution. SrO and CaO dissolved in the biodiesel during the reaction because they were transformed to strontium methoxide and calcium methoxide, respectively. ZnO was the optimum catalyst for the transesterification of rapeseed oil owing to its high activity and minimum weight loss in supercritical methanol. The optimal reaction conditions included a molar ratio of methanol to oil of 40 in the presence of 1.0wt.% ZnO and a reaction time of 10min. The supercritical process with ZnO as a catalyst appears economically viable.
Assuntos
Biocombustíveis , Metais/química , Metanol/química , Óxidos/química , Óleos de Plantas/química , Catálise , Ácidos Graxos Monoinsaturados , Óleo de Brassica napusRESUMO
Catalytic hydrodechlorination of polychlorinated biphenyls (PCBs) in the presence of transformer oil was carried out in a batch mode to detoxify PCBs and to recycle the treated oil. Various metal supported catalysts, including 0.98 wt% Pt, 0.79 wt% Pd and 12.8 wt% Ni on gamma -alumina (gamma -Al(2)O(3)) support, and 57.6 wt% Ni on silicon oxide-aluminum oxide (SiO(2)-Al(2)O(3)) support were used for the hydrodechlorination. Metal particle size of the Pt catalyst was 2.0 nm and metal particle sizes of the Pd and Ni catalysts were in the range of 6.4-6.9 nm. Various supercritical fluids, supercritical carbon dioxide (scCO(2)), supercritical propane (scPropane), supercritical dimethyl ether (scDME) and supercritical isobutane (scIsobutane) were used as reaction media. PCBs conversion, dechlorination degree of PCBs, was measured using gas chromatograph (GC) with an electron capture detector (ECD). The hydrodechorination degree increased in the order Ni > Pd > Pt, possibly due to higher metal loading and larger metal size of the Ni catalysts. At temperatures below 175 degrees C, scCO(2) was effective as the reaction media for the catalytic hydrodechlorination of PCBs in the presence of the transformer oil. However, PCBs conversion decreased significantly when the hydrodechlorination was carried out in a homogeneous phase with using scPropane, scDME or scIsobutane as a reaction medium. This was attributed to dilution effect of the supercritical fluids. Molecular weights of the transformer oils before and after the catalytic hydrodechlorination were analyzed using high-performance size exclusion chromatography (HPSEC). The molecular weight of the treated oil with 100 % PCBs conversion did not change after the catalytic hydrodechlorination at 200 degrees C. This process has proven to be effective to detoxify PCBs containing transformer oil and to recycle the treated oil.
Assuntos
Cloro/isolamento & purificação , Conservação dos Recursos Naturais , Petróleo/análise , Bifenilos Policlorados/análise , Catálise , Cloro/química , Cromatografia em Gel , Cromatografia Líquida de Alta Pressão , Microscopia Eletrônica de Transmissão , Peso Molecular , SolventesRESUMO
Continuous catalytic hydrodechlorination of polychlorinated biphenyls (PCBs) in the presence of transformer oils was carried out in a fixed bed reactor using a 57.6 wt% Ni on silicon oxide-aluminum oxide (SiO(2)-Al(2)O(3)) catalyst. Reaction temperatures ranging 150-300 degrees C, PCBs concentrations ranging 50-200 ppm, and reaction times ranging 1-8 h were tested. At a higher reaction temperature or at a lower PCBs concentration, catalytic activity was higher and complete dechlorination of PCBs resulted even at long reaction time. Catalyst regeneration using hexane and 0.1 M sodium hydroxide (NaOH) was effective to restore the catalytic activity. Fresh, spent and regenerated catalysts were characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis. XRD analysis revealed growth of Ni crystallite size of the spent and the regenerated catalysts. XPS analysis showed that a considerable amount of chlorine and carbon species were deposited on the surface of the spent catalyst, which may play a role in the catalysts deactivation.