Optimization of pretreatment methods for N-nitrosamine compounds in ready-to-eat aquatic products / 预防医学

Objective@#To optimize the pretreatment method of N-nitrosamine compounds in ready-to-eat aquatic products. @*Methods@#Market-sold ready-to-eat aquatic products were collected, homogenized and distilled by steam. The samples were extracted for 10 minutes using dispersive liquid-liquid microextraction (DLLME) with ethanol, trichloromethane and sodium chloride (3.0 g). After centrifugation, the organic phase in the lower layer was collected and subjected to gas chromatography-tandem mass spectrometry (GC-MS/MS). The six common N-nitrosamine compounds were determined in ready-to-eat aquatic products using multiple reaction monitoring mode (MRM) and quantified by the internal standard method. @*Results@#The optimized method exhibited a good linear relationship at concentrations of 10.0 to 500 μg/L for determination of 6 N-nitrosamine compounds (correlation coefficient of greater than 0.999), with 0.05 to 0.60 μg/kg limit of detection, 0.15 to 1.60 μg/kg limit of quantitation, mean spiked recovery rates of 71.8% to 108.9%, and relative standard deviations of 1.4% to 8.6%. N-Nitrosodimethylamine showed the highest detection rate in 20 market-sold ready-to-eat aquatic products (90%), and the detection rates of N-Nitrosopyrrolidine, N-Nitrosodiethylamine and N-dibutylnitrosamine were 15%, 10% and 10%, respectively. @*Conclusion@#Steam distillation combined with DLLME may optimize the pretreatment method of N-nitrosamine compounds in ready-to-eat aquatic products and meet the measurement requirements.

Regorafenib Suppresses Migration of and Induces Cell Cycle Arrest and Apoptosis in MCF-7 Cells

This study investigated the mechanism underlying the suppression of estrogen receptor-positive MCF-7 cell growth by regorafenib. MCF-7 cells were treated with regorafenib, and the effect of regorafenib on multiple cancer-associated pathways was evaluated. Although regorafenib effectively inhibited the proliferation of MCF-7 cells, it had no effect on the proliferation of the normal breast epithelial cell line MCF10A. Regorafenib suppressed MCF-7 cell migration, probably by regulating the homeostatic expression of matrix metalloproteinases and the tissue inhibitor of MMPs. Furthermore, it upregulated p21 expression, downregulated cyclin B1 and cyclin D1 expresssions, and caused cell cycle arrest. In addition, regorafenib induced apoptosis in MCF-7 cells by reducing Mcl-1 expression and activating caspase signaling. These results demonstrate that regorafenib has the potential to be an effective drug for treating breast cancer

Targeting EZH2 depletes LMP1-induced activated regulatory T cells enhancing antitumor immunity in nasopharyngeal carcinoma

Objective: Regulatory T cells (Tregs) are critical factors that impair antitumor immunity. Epstein–Barr virus (EBV)-encoded latent membrane protein 1 (LMP1) is one of the most pathogenic factors in nasopharyngeal carcinoma (NPC). However, the role of EBV-encoded LMP1 in regulating Treg generation in NPC remains unclear. Materials and Methods: The in vitro stability of activated Tregs (aTregs) influenced by LMP1 was analyzed by flow cytometry. The inhibitory effects of LMP1-HONE1 antigen-induced aTregs on tumor-associated antigen (TAA)-specific T cells were analyzed in vitro and in vivo. Finally, the expression of LMP1, Foxp3, and enhancer of zeste homolog 2 (EZH2) were analyzed in samples from 86 NPC patients by immunohistochemistry and immunofluorescence. Results: LMP1 upregulated the expression of EZH2, which increased the stability of aTregs in vitro. EZH2 inhibitor, DZnep, depleted LMP1-HONE1 antigen-induced aTregs in vitro and led to potent TAA-specific T cell antitumor immunity in vivo. In NPC tissues, LMP1 expression level was positively correlated with the number of EZH2+ Tregs, which was positively correlated with clinical stage and overall survival. Conclusions: EZH2 is essential for maintaining the stability and inhibitory functions of aTregs that are induced by EBV-encoded LMP1 in NPC

Determination of furans in tea by headspace-gas chromatographic mass spectrometry / 预防医学

Objective@#To establish a method for the determination of furans in tea by headspace-gas chromatographic mass spectrometry. @*Methods@#The 20% sodium chloride solution and isotope internal standards were added to the crushed and weighed tea sample. Furan, 2-methylfuran, 3-methylfuran, 2,5-dimethylfuran were separated by HP-PLOT Q capillary column and then determined by gas chromatography mass spectrometry with electron impact ionization mode.@*Results@# In the range of 5-400 ng, good linear relationships were observed in the four furan compounds, with the correlation coefficients ranging from 0.999 2 to 0.999 6. The detection limits ranged from 0.2 to 1.9 μg/kg, the quantification limit ranged from 0.4 to 3.1 μg/kg. The recovery rates of furans ranged from 95.4% to 128.2% when spiked at 5.0, 20.0 and 100.0 μg/kg, and the relative standard deviations ranged from 0.8% to 11.3%. Eighty-one tea samples were determined, the concentration of four furan compounds was highest in black tea, followed by dark tea, oolong tea, green tea and scented tea. @*Conclusion@# Headspace-gas chromatography-mass spectrometry can reduce the matrix interference of tea, and meet the requirements in the linear range, recovery and precision, which is suitable for simultaneous determination of four furan compounds in tea.

Risk factors analysis of atrial fibrillation after radical esophagectomy / 中国胸心血管外科临床杂志

@#Objective     To analyze the risk factors of atrial fibrillation (AF) after radical esophagectomy, providing the basis for prevention and treatment of AF after radical esophagectomy. Methods     We conducted a retrospective analysis of 335 patients' clinical data, who accepted laparoscopic combined thoracic or open radical esophagectomy in the same treatment group at Department of Thoracic Surgery of Shengjing Hospital of China Medical University between January 2014 and August 2016. There were 262 males and 73 females at age of 65.1 (43-78) years. Results     There were 48 of 335 patients with AF within 1 week after surgery. By univariate analysis: age, gender, history of peripheral vascular disease and cardiac stents or angina pectoris, preoperative brain natriuretic peptide (BNP), preoperative left ventricular diastolic dysfunction, operation pattern, intraoperative blood transfusion and lymph nodes and pericardial adhesion were possible risk factors. By multivariate analysis: age, gender, history of cardiac stents or angina pectoris, preoperative BNP, operation pattern, intraoperative blood transfusion and lymph nodes and pericardial adhesion were risk factors. Conclusion     The risk factors of AF after radical esophagectomy are age, gender, history of cardiac stents or angina pectoris, preoperative BNP, operation pattern, intraoperative blood transfusion and lymph nodes and pericardial adhesion. Perioperative positive intervention to above factors may reduce the incidence of postoperative AF.

Comparison of serum PCT and CRP levels in patients infected by different pathogenic microorganisms: a systematic review and meta-analysis

To avoid the abuse and misuse of antibiotics, procalcitonin (PCT) and C-reactive protein (CRP) have been used as new approaches to identify different types of infection. Multiple databases were adopted to search relevant studies, and the articles that satisfied the inclusion criteria were included. Meta-analyses were conducted with Review Manager 5.0, and to estimate the quality of each article, risk of bias was assessed. Eight articles satisfied the inclusion criteria. The concentrations of both PCT and CRP in patients with bacterial infection were higher than those with non-bacterial infection. Both PCT and CRP levels in patients with G− bacterial infection were higher than in those with G+ bacterial infection and fungus infection. In the G+ bacterial infection group, a higher concentration of CRP was observed compared with fungus infection group, while the difference of PCT between G+ bacterial infection and fungus infection was not significant. Our study suggested that both PCT and CRP are helpful to a certain extent in detecting pneumonia caused by different types of infection.