ABSTRACT
Peri-operative dexmedetomidine can reduce rates of delirium immediately after surgery. We aimed to assess the effect of dexmedetomidine on cognition up to six postoperative months and its association with changes in serum concentrations of brain-derived neurotrophic factor on the third and seventh postoperative days. We randomly allocated 535 patients aged 65 years or more undergoing scheduled gastro-intestinal laparotomy to: intra-operative dexmedetomidine, 0.5 µg.kg-1 bolus followed by 0.4 µg.kg-1 .hr-1 infusion (n = 269), or placebo (n = 266). Dexmedetomidine reduced the rate of cognitive impairment: on the third postoperative day, 40/269 vs. 65/266, p = 0.006; on the seventh postoperative day, 31/269 vs. 49/266, p = 0.03 and at one postoperative month, 42/250 vs. 61/248, p = 0.04. Cognitive impairment at seven postoperative days was associated with changes in brain-derived neurotrophic factor concentrations on the third and seventh postoperative days; area under the receiver operating characteristic curve 0.63, p < 0.001 and 0.58, p = 0.016, respectively. Intra-operative dexmedetomidine reduced cognitive decline up to one postoperative month in elderly patients undergoing scheduled laparotomy, which was associated with changes in serum brain-derived neurotrophic factor.
Subject(s)
Cognitive Dysfunction/prevention & control , Dexmedetomidine/pharmacology , Hypnotics and Sedatives/pharmacology , Intraoperative Care/methods , Postoperative Complications/prevention & control , Aged , Aged, 80 and over , Brain-Derived Neurotrophic Factor/blood , Cognitive Dysfunction/blood , Female , Humans , Male , Postoperative Complications/blood , Prospective StudiesABSTRACT
Porous titania microspheres with a very narrow particle size distribution (PSD) were synthesized by polymerization-induced colloid aggregation (PICA). After being sintered, the titania microspheres that are obtained have an average diameter of 3.5 microm, a surface area of 36.7 m2/g, an average pore volume of 0.30 mL/g, and an average pore diameter of 32.2 nm. The microspheres possess enough rigidity to withstand high packing pressure and are very useful as a new kind of chromatographic packing material for high performance liquid chromatography (HPLC).
ABSTRACT
Ethylstyrene-divinylbenzene-coated TiO2 (ES-DVB-TiO2) was synthesized by at first bonding of vinyltriethoxysilane with hydroxyl group on titania and secondly by addition polymerization of vinyltriethoxysilane and ethylstyrene-divinylbenzene. The hydrophobic selectivity, absolute mobile phase sensitivity, and stability of the stationary phase were evaluated. Finally, several kinds of practical separations were tested on ES-DVB-TiO2. These examples showed that ES-DVB-TiO2 synthesized in our laboratory was a good reversed-phase stationary phase.
Subject(s)
Chromatography, High Pressure Liquid/instrumentation , Polystyrenes , Titanium , Benzene Derivatives/analysis , Beverages/analysis , Caffeine/analysis , Chromatography, High Pressure Liquid/methods , Ion Exchange ResinsABSTRACT
Porous titania microspheres (surface area: 36.7 m2/g, average pore volume: 0.30 mL/g, average pore diameter: 32.2 nm, average diameter: 3.5 microns) with a very narrow particle size distribution, were synthesized by refluxing polymerized-induced colloid aggregation (PICA), with octadecyltrimethoxysilane in toluene as a solvent for 8 h, and octadecyltitania stationary phase (ODT) was obtained. The carbon content and hydrophobic selectivity of the stationary phase were 2.87% (i.e. 0.66 mumol/m2) and 0.4638, respectively. ODT showed good chromatographic performances when it was used to separate the neutral and basic solutes using methanol solution as a mobile phase.
