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Objective@#To develop a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method with cation exchange-based solid phase extraction (SPE) for determination of tetrodotoxin (TTX) in salted pufferfish. @*Methods@#Evenly crushed salted pufferfish samples were subjected to ultrasound-assisted extraction with 0.5% acetic acid/50% methanol/water. The extract was cleaned with cation exchange-based SPE cartridge and eluted with 0.3% hydrochloric acid and 50% acetonitrile/water. The eluent was neutralized with ammonia and separated with a Waters XBridgeTM BEH Amide column (150 mm×3.0 mm, 1.7 μm), and determined using LC-MS/MS in a multiple reaction monitoring mode.@*Results@#The matrix effects of TTX were 85.7%-92.4%, and the matrix suppression effect was under effective control following clean-up procedures using the optimized SPE method. The TTX showed a good linear relationship at the range of 2.0 to 4 000 μg/kg, with a correlation coefficient (r2) of 0.999 2. The limits of detection and quantitation for TTX in sample matrix were 1.0 μg/kg and 2.0 μg/kg, respectively. The mean spiked-recovery rates were 81.2% to 96.5% at spiked amounts of 2.0, 200 μg/kg and 2 200 μg/kg, with relative standard deviations (RSDs) of 4.3% to 7.5%. The intraday accuracy and precision of TTX were 84.4% to 95.6% and 4.9% to 5.8% in quality control samples, and the interday accuracy and precision of TTX were 86.1% to 94.9% and 5.5% to 8.5% in quality control samples. The detection of TTX was 60.5% in 38 market-sold salted pufferfish products using the established LC-MS/MS method.@*Conclusion@#The established LC-MS/MS method is effective for accurate quantitative determination of TTX in salted pufferfish.
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Objective @#To learn the characteristics of second-line drug resistance and related gene mutations of multidrug-resistant Mycobacterium tuberculosis ( MDR-TB ) Beijing genotype strains. @*Methods@#The MDR-TB isolates in Hwa Mei Hospital from 2017 to 2019 were enrolled and detected using RD105 deletion-targeted multiplex polymerase chain reaction (PCR). The proportion method for drug susceptibility test was used to detect the drug-resistant profiles against kanamycin, amikacin, capreomycin, ofloxacin and levofloxacin. The gene sequencing of rrs, tlyA, eis, gidB, gyrA and gyrB was conducted by PCR compared with H37RV strain. The differences in the rates of drug resistance and mutation between Beijing and non-Beijing genotype strains were examined to understand the characteristics of Beijing genotype strains. @*Results@#There were 106 Beijing genotype and 27 non-Beijing genotype strains in 133 MDR-TB isolates. The drug resistance rates of kanamycin, amikacin, capreomycin, ofloxacin and levofloxacin in Beijing genotype strains were 9.43%, 7.55%, 3.77%, 32.08% and 32.08%, respectively. The rates of quasi-extensive and extensive drug resistance in Beijing genotype strains were 30.19% and 7.55%. The gene mutation rates of rrs, tlyA, eis, gidB, gyrA and gyrB in Beijing genotype strains were 7.55%, 7.55%, 1.89%, 2.83%, 36.79% and 2.83%, respectively. There were no significantly differences between Beijing and Non-Beijing genotype strains in the factors above ( P>0.05 ). The gene rrs, tlyA, eis, gidB, gyrA and gyrB had 2, 1, 2, 2, 5 and 3 mutation types, respectively, with single base substitution as the main type. @*Conclusion@#Beijing genotype strains are dominant in MDR-TB, with high resistance to fluoroquinolones and mainly gyrA gene mutation.
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Objective @#To develop an analytical method of ibotenic acid (IBA) and muscimol (MUS) in wild mushroom by dansyl chloride (DNSCl) derivatization-liquid chromatography-tandem mass spectrometry (LC-MS/MS), and to provide technical support for etiological identification of mushroom poisoning events.@*Methods @#The sample was extracted with hydrochloric acid solution, derived by bimolecular DNSCl, diluted and inorganic salts precipitated with acetonitrile. The extract was separated by a waters XBridgeTM BEH C18 column and measured by LC-MS/MS.@*Results @#The limits of detection for IBA and MUS in wild mushroom were 0.15 mg/kg and 0.1 mg/kg, respectively. Good linear relationship was obtained for IBA and MUS at the range of 0.5-250 mg/kg with the correlation coefficient of 0.997 and 0.999, respectively. The average recoveries at three spiking levels were 84.5%-102.0% with relative standard deviations (RSDs, n=6) of 4.7%-8.6% for IBA. The average recoveries were 88.6%-95.4% with RSDs (n=6) of 4.9%-7.5% for MUS. @*Conclusion @#The optimized sample extraction and bimolecular DNSCl derivatization conditions can achieve rapid and accurate analysis of IBA and MUS in wild mushroom poisoning sample.
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@#Objective To compare the efficacy of percutaneous closure guided by transthoracic echocardiography or angiography in the treatment of patent ductus arteriosus (PDA). Methods Literature databases such as CNKI, VIP, Wanfang Database, PubMed, Cochrane Library were searched for collecting published literatures on percutaneous closure for PDA guided by transthoracic echocardiography and angiography, retrieval time limit was up to April 2019. Two evaluators independently screened the literature, extracted the data and evaluated the quality according to inclusion and exclusion criteria. The collected data were analyzed by RevMan 5.3 software. Results Eight studies were included finally, with a total sample size of 681 cases. Meta-analysis showed that there was no statistical difference in the operative success rate between the echocardiography group and the angiography group (RR=0.99, 95%CI 0.97- 1.01, P=0.40). Postoperative complications were less in the echocardiography group than those in the angiography group (RR=0.26, 95%CI 0.11-0.59, P=0.001).The operation time (P<0.000 01), amount of intraoperative radiation (P< 0.000 01), exposure time (P<0.000 01), hospitalization days (P<0.000 01) and hospitalization costs (P<0.000 01) in the echocardiography group were less or shorter than those in the angiography group, and the difference was statistically different. Conclusion Compared with angiography-guided, transthoracic echocardiography-guided percutaneous closure for PDA is a safe and effective method with less trauma, lower cost, and can replace angiography as one of the guiding methods for PDA.