Objective To investigate a rapid detection method for compressed Nitrous oxide(N2O).Methods The GC-MS system was employed under conventional chromatographic conditions(without replacing standard columns or utilizing headspace sampling)by directly injecting a small gas sample for analysis.N2O identification was performed via NIST spectral library matching,while qualitative and quantitative purity assessments were achieved by monitoring the relative abundance variation of the characteristic fragment ion m/z 30 to eliminate CO2 interference.Results The fragment ion m/z 30 demonstrated specificity for N2O identification.A linear correlation was observed between the peak area of m/z 30 and N2O purity(y=22.741x-1.4565,R2=0.912 6),enabling quantitative purity determination.Additionally,the abundance of m/z30 exhibited a correlation with N2O in CO2 mixtures(y=0.7787x-0.0387,R2=0.722 2).Conclusion Conventional N2O identification typically requires dedicated GC-MS systems,gas-specific chromatographic columns,and headspace sampling.This study successfully utilized routine chromatographic conditions for organic toxicant screening to achieve rapid N2O analysis.The proposed method holds practical significance for compressed N2O identification in forensic and analytical applications.

Objective To investigate a rapid detection method for compressed Nitrous oxide(N2O).Methods The GC-MS system was employed under conventional chromatographic conditions(without replacing standard columns or utilizing headspace sampling)by directly injecting a small gas sample for analysis.N2O identification was performed via NIST spectral library matching,while qualitative and quantitative purity assessments were achieved by monitoring the relative abundance variation of the characteristic fragment ion m/z 30 to eliminate CO2 interference.Results The fragment ion m/z 30 demonstrated specificity for N2O identification.A linear correlation was observed between the peak area of m/z 30 and N2O purity(y=22.741x-1.4565,R2=0.912 6),enabling quantitative purity determination.Additionally,the abundance of m/z30 exhibited a correlation with N2O in CO2 mixtures(y=0.7787x-0.0387,R2=0.722 2).Conclusion Conventional N2O identification typically requires dedicated GC-MS systems,gas-specific chromatographic columns,and headspace sampling.This study successfully utilized routine chromatographic conditions for organic toxicant screening to achieve rapid N2O analysis.The proposed method holds practical significance for compressed N2O identification in forensic and analytical applications.

Inhaled antibiotics such as colistin and ciprofloxacin are increasingly used to treat bacterial lung in-fections in cystic fibrosis patients.In this study,we established and validated a new HPLC-MS/MS method that could simultaneously detect drug concentrations of ciprofloxacin,colistin and ivacaftor in rat plasma,human epithelial cell lysate,cell culture medium,and drug transport media.An aliquot of 200 μL drug-containing rat plasma or cell culture medium was treated with 600 μL of extraction solution(acetonitrile containing 0.1％ formic acid and 0.2％ trifluoroacetic acid (TFA)).The addition of 0.2％ TFA helped to break the drug-protein bonds.Moreover,the addition of 0.1％ formic acid to the transport medium and cell lysate samples could significantly improve the response and reproducibility.After vortexing and centrifuging,the sample components were analyzed by HPLC-MS/MS.The multiple re-action monitoring mode was used to detect the following transitions:585.5-101.1 (colistin A),578.5-101.1 (colistin B),393.2-337.2 (ivacaftor),332.2-314.2 (ciprofloxacin),602.3-101.1 (polymyxin 81 as internal standard (IS)) and 595.4-101.1 (polymyxin B2 as IS).The running time of a single sample was only 6 min,making this a time-efficient method.Linear correlations were found for colistin A at 0.029-5.82 μg/mL.colistin B at 0.016-3.14 μg/mL.ivacaftor at 0.05-10.0 μg/mL,and ciprofloxacin at 0.043-8.58 μg/mL.Accuracy,precision,and stability of the method were within the acceptable range.This method would be highly useful for research on cytotoxicity,animal pharmacokinetics,and in vitro drug delivery.

Objective To investigate the effects of 5-hydroxy-1-methylhydantoin (HMH) on kidney injury induced by paraquat (PQ). Methods Fifteen SPF healthy Kunming mice were randomly divided into normal saline (NS) control group, PQ poisoning model group and HMH intervention group, with 5 mice in each group. PQ poisoning model was challenged by one-time gavage of 30 mg/kg PQ solution. The NS group received the same amount of NS by gavage. The HMH group was given 100 mg/kg of HMH immediately after the model was made and continued to be gavaged. Mice in each group were sacrificed 1 day after HMH gavage and heart blood and renal tissue were harvested for examination. The morphological changes of renal tissue were observed under light microscope by hematoxylin-eosin (HE) staining. The content of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) in renal tissue were detected according to the instructions of the kit. The expression of heme oxygenase-1 (HO-1) and interleukin-1β (IL-1β) in renal tissues were detected by Western Blot. The serum metabolites were detected by gas chromatography time-of-flight mass spectrometry (GC-TOF-MS), the overall distribution of each sample was observed by principal component analysis (PCA), the accuracy of the model was evaluated by multidimensional analysis orthogonal partial least squares-discriminant analysis (OPLS-DA), and the difference metabolites were screened by variable importance in the projection (VIP) value > 1. Results Light microscopic observation showed that: glomerular structure in NS group was clear, there was no hyperemia and inflammatory cell infiltration in renal interstitium and blood vessels. In PQ group, some glomeruli atrophy and necrosis, capillary congestion in glomeruli, infiltration of inflammatory cells around glomeruli, swelling of renal tubular epithelial cells, slight stenosis of lumen, and occasional necrosis and exfoliation of epithelial cells occurred. The degree of kidney injury in HMH group was significantly less than that in PQ group. Compared with the NS group, the content of MDA in the PQ group was significantly increased (nmol/g: 6.70±0.84 vs. 2.70±0.43, P < 0.01) and the activity of SOD was significantly decreased (kU/L: 33.30±4.66 vs. 50.20±3.23, P < 0.05), the protein expression of HO-1 and IL-1β were significantly increased (HO-1/β-actin: 1.11±0.12 vs. 0.61±0.13, IL-1β/β-actin: 0.93±0.13 vs. 0.32±0.06, both P < 0.05). Compared with the PQ group, the content of MDA in the HMH group was significantly decreased (nmol/g: 5.10±0.93 vs. 6.70±0.84, P < 0.05) and the activity of SOD was significantly increased (kU/L:61.00±9.02 vs. 33.30±4.66, P < 0.05), the protein expression of HO-1 was significantly decreased (HO-1/β-actin:0.77±0.07 vs. 1.11±0.12, P < 0.05), however, there was no significant difference in the protein expression of IL-1β (IL-1β/β-actin: 0.87±0.13 vs. 0.93±0.13, P > 0.05). Metabolite detection results showed that: compared with NS group, the levels of creatinine, glycine, succinic acid, fumaric acid and citric acid were significantly increased in the PQ group (VIP value was 1.50, 1.58, 1.64, 1.74 and 1.95 respectively, all P < 0.05), while the levels of palmitic acid, α-tocopherol and 6-phosphogluconic acid were significantly decreased (VIP value was 1.10, 1.55 and 1.56 respectively, all P < 0.05). Compared with the PQ group, the levels of creatinine and citric acid were significantly decreased in the HMH group (VIP value was 1.50 and 1.86, both P < 0.05), while trans-4-hydroxy-proline, D-glyceric acid, 2, 6-fructose phosphate, 6-phosphate gluconic acid and aminomalonic acid were significantly increased (VIP value was 1.36, 1.55, 1.63, 1.68 and 1.76 respectively, all P < 0.05). Conclusions HMH protects kidney injury caused by PQ poisoning by correcting tricarboxylic acids cycle disturbance, lipid peroxidation and energy metabolism disturbance, and its mechanism is related to the regulation of HO-1 protein expression through Nrf2 pathway.

Objective To establish a HPLC-MS method for determination of aconitum alkaloids in biological samples. Methods The aconitum alkaloids were extracted from the whole blood by using acetonitrile-methanol (5:1 v/v) and then analyzed using HPLC-MS in multiple reaction monitoring (MRM) mode with positive ionization. The analytical column was Agilent Zorbax SB C18 (2.1mm×50mm, 1.8μm)and the mobile phase were water containing 0. 1 % formic acid : acetonitrile (60 : 40 v/v) in isocratic elution. Results The retention time of detection of the aconitine, hypaconitine and mesaconitine were 0.73 min, 0.77 min and 0.63 min, and the precursor product ion combinations of m/z 646.4 → 586.4, 616.1 → 556.5 and 632.4 → 572.1 were used for quantitative analysis, respectively. Calibration curve was linear within the range of 0.1-250 ng/mL with the LOD was 0.1ng/mL, and the coefficient of variation (CV) less than 5.42 % (n=6). The extraction recoveries of aconitine in blood were more than 90 %.Conclusion The results demonstrated that the present method was reliable and robust for natural drugs.

Objective To investigate the roles of sphingosine kinasel (SPK1) in apoptosis,invasiveness and multidrug resistance of human hepatocellular carcinoma cell line BEL-FU.Methods BEL-FU cells were infected with adenovirus carrying SPK1wT gene and SPK1siRNA (Ad-H1-SPK1) gene.Their effects on biological characteristics of BEL-FU cells were evaluated by MTT,cellular SPK enzyme activity assay,Transwell Migration Technology and Western-blot,respectively.Results AdSPK1wT significantly increased SPK activity but SPK1siRNA(Ad-H1-SPK1) decreased SPK activity.Over expression of SPK1 suppressed the apoptosis induced by DMS(Dimethyl sphingosine,DMS) and enhanced migration of BEL-FU cells.The cells infected with SPK1 siRNA( Ad-H1-SPK1)significantly increased the apoptosis induced by DMS and inhibited the migration of human hepatocellular carcinoma cells.The expression of multidrug resistance-related protein (MRP1) of cells infected with SPK1siRNA (Ad-H1-SPK1) was suppressed significantly compared with the control group,while the expression of MRP1 infected with Ad- SPK1wT was enhanced.Conclusion SPK1 activity is closely associated with apoptosis、migration and multidrug resistance of human hepatocellular carcinoma cells,therefore,it may serve as a new target for HCC treatment.

Objective To evaluate the etiology and clinical features of jejunoileum bleeding.Methods Seventy-two patients admitted in 7 hospitals of Shangdong province for jejunoileum bleeding from January 1998 to December 2008 were enrolled in the study. There were 46 males and 26 females with mean age of 47 years (ranged 13-85 years). The jejunoileum bleeding was confirmed by means of endoscopy, images or surgery. The causes, diagnostic methods and major clinical manifestations were retrospectively analyzed. Results The most frequent cause of jejunoileum bleeding was tumor (42/72,58.3 %), followed by enteritis (9/72, 12.5 %), diverticulum ( 7/72, 9. 7%), angiopathy (7/72,9.7%), Crohn's disease (3/72,4.2%). Differences were significant in constituent ratio of cause of jejunoileum hemorrhage between male and female and between jejunum and ileum (P＜0.05).Hematochezia or hematochezia with abdominal pain was the first presentation. The jejunoileum bleeding in 54. 2% patients was diagnosed by laparotomy, 23. 6% by capsule endoscopy, 9.7% by selective angiography, 6.9% by small bowel series and enteroclysis, 2.8% by colonoscopy and 2.8% by push enteroscopy. The complications of jejunoileum bleeding were anemia, intestinal obstruction,peritoneal metastasis, shock, ankylenteron and intestinal perforation. Conclusions Intestinal tumor is the most common cause in jejunoileum bleeding, especially in jejunum. Whereas the enteritis,diverticulum and angiopathy were often found in ileum. The capsule endoscopy and push enteroscopy are recommended in diagnosis of jejunoileum bleeding.