Carotenoids are natural pigments synthesized by plants and photosynthetic microorganisms, some of which, like β-carotene, are precursors of vitamin A, and others such as lutein and lycopene might function in the prevention of age-related macular degeneration and prostate cancer, respectively. Mass spectrometry provides high sensitivity and selectivity for the identification and quantitative analysis of carotenoids in biological samples, and previous studies have described how atmospheric pressure chemical ionization (APCI) offers distinct advantages over electrospray and fast atom bombardment for the analysis of specific carotenoids. Since APCI product ion tandem mass spectra have been reported for only a few carotenoids, a detailed investigation of twelve carotenes and xanthophylls was carried out using both positive ion and negative ion APCI tandem mass spectrometry with collision-induced dissociation. Using protonated molecules as precursor ions in positive ion mode and radical anions in negative ion mode, characteristic fragment ions were identified that may be used to distinguish between carotenoids.

BackgroundSeveral kinds of cancer surgeries with propofol-based total intravenous anesthesia (TIVA) have been shown to have better outcomes than those with sevoflurane-based inhalational anesthesia (INHA). However, the effects of this anesthetic technique have not been investigated in patients with gastric cancer. In this study, the authors retrospectively examined the link between the choice of anesthetic technique and overall survival in patients undergoing gastric cancer resection.MethodsWe conducted a retrospective analysis of the database of all patients undergoing gastric cancer resection for gastric cancer between 2007 and 2012. Patients who received TIVA or INHA were administered patient-controlled intravenous analgesia for 72–120 hours postoperatively. Survival was estimated using the Kaplan–Meier log-rank test, and associations between anesthetic technique and outcomes were analyzed using Cox proportional hazards regressions after propensity matching.ResultsA total of 2,856 anesthetics using INHA or TIVA were delivered in the study period. After propensity matching, 897 patients remained in each group. According to Kaplan–Meier analysis, the use of TIVA was associated with improved survival (P<0.001). TIVA was associated with a hazard ratio (HR) of 0.67 (95% confidence interval [CI]: 0.58–0.77) for death in univariate analysis and 0.65 (95% CI: 0.56–0.75) after a multivariate analysis of known confounders in the matched group. Cancer stage (HR =0.74, 95% CI: 0.64–0.86, P<0.001) and degree of differentiation (HR =1.28, 95% CI: 1.11–1.47, P<0.001) were also associated with survival in the univariate analysis in the matched group. In the multivariable Cox model, cancer stage (HR =0.72, 95% CI: 0.62–0.84, P<0.001) and degree of differentiation (HR =1.23, 95% CI: 1.07–1.42, P<0.001) were associated with survival in the matched group.ConclusionThese results indicate that TIVA may be associated with improved survival in gastric cancer patients who undergo resection.

JJ22011-15.

Previous methods for the quantitative analysis of phytosterols have usually used GC-MS and require elaborate sample preparation including chemical derivatization. Other common methods such as HPLC with absorbance detection do not provide information regarding the identity of the analytes. To address the need for an assay that utilizes mass selectivity while avoiding derivatization, a quantitative method based on LC-tandem mass spectrometry (LC-MS-MS) was developed and validated for the measurement of six abundant dietary phytosterols and structurally related triterpene alcohols including brassicasterol, campesterol, cycloartenol, β-sitosterol, stigmasterol, and lupeol in edible oils. Samples were saponified, extracted with hexane and then analyzed using reversed phase HPLC with positive ion atmospheric pressure chemical ionization tandem mass spectrometry and selected reaction monitoring. The utility of the LC-MS-MS method was demonstrated by analyzing 14 edible oils. All six compounds were present in at least some of the edible oils. The most abundant phytosterol in all samples was β-sitosterol, which was highest in corn oil at 4.35 ± 0.03 mg/g, followed by campesterol in canola oil at 1.84 ± 0.01 mg/g. The new LC-MS-MS method for the quantitative analysis of phytosterols provides a combination of speed, selectivity and sensitivity that exceed those of previous assays.