A simple analytical method by means of on-line solid phase extraction followed liquid chromatography-tandem mass spectrometry ( SPE-LC-MS/MS) was developed for the simultaneous quantitation of 4 endocrine disruptors ( triclosan, triclocarban, bisphenol A and nonylphenol) in dairy products. Infant formula and milk samples were dissolved in acetic acid buffer and hydrolyzed by β-glucuronidase/arylsulfatase. Acetonitrile was used as the extract. Then, the mixture was freeze-centrifuged for 10 min and the supernatant was diluted with water, and analyzed via on-line SPE-LC-MS/MS. The sample extracts were concentrated by an Xbridge C8 cartridge and separated on a BEH C18 column with a gradient mobile phase of methanol and water; then analyzed by triple quadrupole mass spectrometry. Mass acquisition was conducted under negative electrospray ionization mode. Quantification was performed by isotopic internal standard calibration. Acceptable linearity (R2>0. 99) was achieved over the range of 0. 005-5. 0 μg/L, with limits of quantification of 0. 03-1. 0μg/kg. Average recoveries of four target compounds (spiked at three concentration levels) ranged from 80. 2%-106. 7%,with relative standard deviation less than 15%. Due to its rapidity, simplicity, and high sensitivity, the method is suitable for the analysis of endocrine disruptors in dairy products. It has been applied in the analysis of raw milk and milk products collected in Beijing. As a result, nonylphenol was found with a high detectable frequency.

Objective To evaluate the clinical significance of intercellular space diameters (ISD)of squamous epithelium by light microscopy (LM) in lower esophagus of erosive reflux esophagitis (ERD),non-erosive reflux disease ( NERD), Barrett esophagus (BE) and healthy controls. Methods A total of 21 ERD and 21 NERD patients with reflux symptoms and confirmed with 24-hour esophageal pH monitoring, 13 BE patients diagnosed by gastroscopy and biopsy, and 20 other healthy controls were enrolled in the study.Samples of ERD, NERD and control group were collected at 2 cm above dentate line, and made HE slides in the conventional way. Images for measurement of ICS were acquired with oil lens ( × 1000). ICS of squamous epithelium was quantitatively measured by computer-assisted morphometry. Ten cells were taken for each sample, 10 consecutive ISD for each cell, i.e. 100 ISD for each subject. Mean ISD was calculated.Results Mean ISDs by LM in control, BE, ERD, and NERD groups were 0. 59, 0. 99, 1.29 and 1.06 μm, respectively. The mean ISDs in BE, ERD, and NERD group were much greater than that in control (P＜0. 05). The mean, maximal and minimal ISDs of group ERD were greater than those of NERD and BE (P = 0. 000). However, the ISDs of NERD and BE are of no significant difference ( P ＞ 0. 05 ). The cut-off value of mean ISD for diagnosis of gastro-esophageal reflux disease (GERD) was 0. 85 μm. Diagnostic sensitivity and specificity for ERD, NERD and BE were 89. 1% and 100. 0%, with reference to clinical symptoms, endoscopy and ISDs above the cut-off value. Conclusion Larger ISDs in lower esophagus by using LM will be found in all subgroups of GERD, including ERD, NERD and BE. Increased ISDs may be one of the markers for diagnosis of ERD, NERD and BE.

Objective:Reflux esophagitis (RE) may be negatively correlated with Helicobacter pylori ( H. pylori) infection, but the conclusion and relevant mechanism is still controversial. This study proposed to explore the correlation between RE and H. pylori infection based on natural population. Methods:From July 2013 to December 2014, 3 940 residents aged 40-69 years were recruited in Linqu County of Shandong Province and Hua County of Henan Province by the whole sampling method. All the subjects underwent gastroscopy, and gastric mucosa biopsy specimens were collected for pathological diagnosis and Warthin-Starry (WS) staining to identify H. pylori infection. Venous blood samples of some subjects were collected for H. pylori immunoglobulin G ( H. pylori-IgG) detection. Also, demographic and sociological data were collected. Chi-square test and logistic regression were used to analyze the correlation between RE and H. pylori infection. Results:A total of 359 cases of RE were detected. Excluding RE and other upper gastrointestinal organic diseases, 3 382 cases were considered as controls. Chi-square test showed that WS staining positive rate in RE group was significantly lower than that in control group ( P=0.023), but there was no significant difference in the positive rate of H. pylori-IgG between the two groups ( P=0.281). There were significant differences between RE group and control group in gender composition, age, body mass index (BMI), smoking, alcohol consumption, education level and mucosal active inflammation. Multivariate regression analysis showed that RE was negatively correlated with gastric mucosa active inflammation [ OR=0.754 (95% CI 0.600-0.949), P=0.016], and positively correlated with male [ OR=4.231 (95% CI 3.263-5.486), P<0.001], age ≥60 years, BMI≥24 kg/m 2 [ OR=1.540 (95% CI 1.220-1.945), P<0.001]. Compared to those aged 40-49 years and 50-59 years, the odds ratio ( OR) of RE in these aged ≥60 years were 1.566 (95% CI 1.144-2.143, P=0.005) and 1.405 (95% CI 1.093-1.805, P=0.008). Conclusion:RE is more closely related to H. pylori present infection. Multivariate analysis showed that RE is negatively correlated with active inflammation of gastric mucosa caused by H. pylori infection, and positively correlated with male, overweight and aged ≥60 years.