ABSTRACT
A method was developed for the determination of fumonisin B1 ( FB1 ) and fumonisin B2 ( FB2 ) in livestock and poultry formula feeds by high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS. After extracted by acetonitrile-water (50: 50, V/V) and purified with MAX solid phase extraction column, the fumonisins were separated by Thermo C18(100 mm×2. 1 mm, 5 μm) column with 0. 1% formic acid in water and methanol as the mobile phase. Multiple reaction monitoring (MRM) was used to acquire mass spectrometric data under electrospray positive ionization mode ( ESI+) . The results showed that the linear correlation coefficients (R2) of fumonisin FB1 and FB2 were all greater than 0. 999 in the range of 1-500 μg/L. The limits of quantitation (LOQ) were 0. 098 and 0. 197 μg/L, and the limits of detection ( LOD) were 0. 328 and 0. 656 μg/L, respectively. At different spiked levels, the recoveries of FB1 and FB2 were ranged from 89. 7% to 95. 1%, and the relative standard deviation ( RSD) was ranged from 3. 2% to 8. 6%. Additionally, the detection rate reached 98. 11% screening through the established method in the 106 livestock and poultry formula feeds collected from markets. This result indicates that the method is suitable for accurate quantitative analysis of FB1 and FB2 in different complicated livestock and poultry formula feeds.
ABSTRACT
ObjectiveTo investigate the role of platelet in mouse pulmonary microvascular endothelial cell (PMVEC) injury caused by lipopolysaccharide( LPS)-activated neutrophil.MethodsPMVECs were obtained from pathogen-free C3H/HeN mice of both sexes aged 6-8 weeks weighing 18-25 g according to the method described by Lim YC et al.Platelets and neutrophils were isolated from mouse blood by twice centrifugation and denaity gradient centrifugation respectively.PMVECs were seeded into twelve- or six-well plates ( 1 or 2 ml/well) after 2-5 passages and were randomly divided into 4 groups (n =31 each): group LPS; group platelets (group P);group neutrophils (group N) and group platelets + neutrophils (group PN).Each well contained about 5 × 107/ml platelets and/or 5 × 105/ml neutrophils respectively.PMVECs were incubated with LPS1 μg/ml at 37 ℃ in a 5％ CO2 humidified atmosphere for 1,6,12,18 and 24 h respectively in all 4 groups.The cells were examined with phase contrast microscope for morphological changes and survival condition.Viability rate,apoptotic rate and activation rate of PMVECs were detected by flow cytometry at each time points.ResultsThere was no significant difference in morphology and number of endothelial cells (ECs) among the 4 groups,while the number of activated ECs was significantly increased but the number of living cells decreased in group PN compared with group LPS.The activation rate of ECs was significantly higher after being incubated with LPS for 6-12 h in groups P and N than in group LPS.The viability rate was significantly lower,while the apoptotic rate and activation rate were significantly higher after ECs were incubated with LPS in group PN than in groups LPS,P and N.ConclusionPlatelets play a decisive role in mouse PMVEC injury induced by LPS activated neutrophils.