Optimization and application of high-throughput supported liquid extraction for simultaneous determination of carotenoids and fat-soluble vitamins in serum.

The demand for analysis of carotenoids (CAR) and fat-soluble vitamins (FSV) is continuously expanding, but currently used sample preparation methods either require complicated extraction procedure or large sample volume, let alone the reliability of the results. This study aimed to develop a fast, high-efficient, and high-throughput method based on supported liquid extraction (SLE) for the simultaneous extraction of FSV and CAR from human serum before using high-performance liquid chromatography-diode array detector (HPLC-DAD) analysis. The optimization of SLE parameters was achieved through response surface methodology (RSM) based on the Box-Behnken design (BBD) and included serum-water-extraction solvent ratio and eluent volume. Under optimal conditions, the proposed method gives acceptable limits of detection (LOD) (0.005-0.3 µg/mL), good recovery (89.6-110.9%) as well as relative standard deviation (RSD) of less than 10.1% by consuming lower serum sample (100 µL) and less sample preparation time (2 min per sample). Compared with liquid-phase extraction (LLE), the SLE delivers rapid extraction with higher recovery, better reproducibility, and lower matrix effect for CAR and FSV analysis. The method has been successfully applied to quantify CAR and FSV levels in serum of healthy individuals and age-related macular degeneration (AMD) patients, demonstrating the feasibility of the proposed method for epidemiology and routine applications.

[Clinical values and optimal cut-off points of basic vital signs in early identification of critical hand, foot, and mouth disease].

OBJECTIVE: To study the clinical values of basic vital signs in early identification of critical hand-foot-mouth disease (HFMD). METHODS: The clinical data of 358 children with severe HFMD [212 cases in stage 2 (central nervous system involvement) and 146 cases in stage 3 (earlier stage of cardiopulmonary failure, critical type)] were reviewed. The diagnostic values of peak temperature and duration of fever, as well as the heart rate (HR), respiratory rate (RR), systolic blood pressure (SBP), and diastolic blood pressure (DBP) in different age groups, for critical HFMD (stage 3) were analyzed using the receiver operating characteristic (ROC) curve. RESULTS: HFMD might progress to critical type in case of HR≥148.5 beats/minutes, RR≥36.5 times/minutes, SBP≥95 mm Hg, and DBP≥59 mm Hg among children aged 0-1 year. HR≥142.5 times/minutes, RR≥31.5 times/mintes, SBP≥103 mm Hg, and DBP≥60.5 mm Hg in children aged 1-2 years had a certain diagnostic value for critical HFMD. HFMD might progress to critical type in case of HR≥139.5 times/minutes, RR≥29.5 times/minutes, and SBP≥103 mm Hg among children≥3 years of age. The sensitivity and specificity of every indicator were higher than 0.517 and 0.769, respectively. The area under the ROC curve (AUC) for peak temperature was 0.507 (P=0.816, compared with AUC=0.5). When the duration of fever was ≥5.5 days, the sensitivity and specificity were 0.589 and 0.571, respectively. CONCLUSIONS: HR, RR, and BP are good indicators to identify critical HFMD (stage 3) early. The optimal cut-off points conform to the age characteristics of children. DBP in children≥3 years of age, peak temperature, and duration of fever have a low value in early identification of critical HFMD.

Reconstitution of glyphosate resistance from a split 5-enolpyruvyl shikimate-3-phosphate synthase gene in Escherichia coli and transgenic tobacco.

A highly N-phosphonomethylglycine (glyphosate)-resistant Pseudomonas fluorescens G2 5-enolpyruvyl shikimate-3-phosphate synthase (EPSPS) was mapped to identify potential split sites using a transposon-based linker-scanning procedure. Intein-mediated protein complementation was used to reconstitute glyphosate resistance from the genetically divided G2 EPSPS gene in Escherichia coli strain ER2799 and transgenic tobacco.