RESUMO
For patients on ventilation without acute respiratory distress syndrome (ARDS), there are, as yet, limited data on ventilation strategies. We hypothesized that driving pressure (DP) and mechanical power (MP) may play key roles for the late development of ARDS in patients without initial ARDS. A post hoc analysis of a database from our previous cohort was performed. The mean DP/MP was computed from the data before ARDS development or until ventilator support was discontinued within 28 days. The association between DP/MP and late development of ARDS within 28 days was determined. One hundred and twelve patients were enrolled, among whom seven developed ARDS. Univariate Cox regression showed that congestive heart failure (CHF) history and higher levels of mean MP and DP were associated with ARDS development. Multivariate models revealed that the mean MP and mean DP were still factors independently associated with ARDS development at hazard ratios of 1.177 and 1.226 after adjusting for the CHF effect. Areas under the receiver operating characteristic curves for mean DP/MP in predicting ARDS development were 0.813 and 0.759, respectively. In conclusion, high mean DP and MP values may be key factors associated with late ARDS development. The mean DP had a better predicted value for the development of ARDS than the mean MP.
RESUMO
The relationship between the antioxidant activities and inhibitory effect of 14 Chinese medicinal herbs against oxidized low-density lipoprotein (LDL) formation was evaluated. Prolongation of the lag phase of LDL oxidation depended on the concentration of the herbs. The concentration of each herb that was able to prolong the lag time by about two-fold was calculated and expressed as doubling-time concentration. The lower the doubling-time concentration, the stronger the inhibitory effect exhibited toward LDL oxidation. Among them, Chrysanthemi Flos (Chrysanthemum morifolium ramat; gan jú hua), Crataegi Fructus (Crataegus pinnatifida Bge. var. major N.E.Br.; shan zha), and Roselle (Hibiscus sabdariffa Linn.; luò shén) showed significant inhibitory effects. Correlation coefficients between doubling-time concentration and radical-scavenging activities were high; the total phenolic content was also high. In conclusion, phenolic compounds contributed not only to antioxidant activities, but also to the inhibitory effect against LDL oxidation. Chrysanthemi Flos, Crataegi Fructus, and H. sabdariffa, with lower doubling-time concentrations, could be potent phytochemical agents to reduce LDL oxidation and prevent the progression of atherosclerosis.
RESUMO
The surface equation of state (γ vs Γ/Γref), based on the experimental data from rapid expansion of a pendant bubble, has been used on studying the adsorption kinetics for C12E6 (Pan et al. J. Colloid Interface Sci. 1998, 205, 213) and C14E8 (Lin et al. J. Colloid Interface Sci. 2001, 244, 372). In those studies, the relationship between surface tension γ and relative surface concentration Γ/Γref was applied, and the γ(Γ/Γref) data profiles were found very useful for the determination of the adsorption isotherm and its parameters. In this work, the value of Γref was evaluated from the equilibrium surface tension data γ(C) and the Gibbs adsorption equation. It was found that the dependence of γ vs Γ is more sensitive than γ(Γ/Γref) and brings more help to studying the adsorption kinetics. The role of γ(Γ) data was examined using the equilibrium γ(C) and dynamic γ(t) data of six nonionic polyoxyethylene surfactants CmEn and two alcohols. The γ(Γ) data play an important role on the determination of the adsorption isotherm, model parameters, and controlling mechanism, and also on the evaluation of surfactant diffusivity. Applying γ(Γ) data with γ(ln C) data does bring a much better result on studying the adsorption behavior. According to the γ(Γ) data, (i) the Langmuir isotherm clearly fails to describe the above nonionic surfactants, and (ii) the interaction between the adsorbed surfactant molecules is significant.