Objective To investigate the correlation between dynamic changes in esophageal impedance and dilated intercellular space (DIS) of patients with acid-induced non erosive reflux disease (NERD).Methods From September 2013 to July 2014,a total of 35 patients with NERD and 20 healthy controls were selected and underwent 24 h multichannel intraluminal impedance and pH monitoring (MII-pH monitoring),acid perfusion test and gastroendoscopy examination.One piece of mucosa tissue was taken under gastroendoscope from the anterior and posterior walls at 2 cm above the dentate line of the esophagus.Intercellular space (ICS) of the esophageal epithelia cells was measured by software after hematoxylin and eosin staining.t test and variance analysis were performed for statistical analysis.Pearson correlation analysis was used for correlation analysis.Results Impedance baseline of distal esophagus and impedance recovery rate of patients with NERD were lower than those of healthy control group,which were (2 998±701) Ω vs (3 880±1 054) Ω and (30.1±14.0) Ω/min vs (53.0±14.5) Ω/min,and the differences were statistically significant (t=3.65,5.41;both P＜0.01).Compared with healthy control group,ICS of the esophageal epithelial cells was obviously wider (1.03 ± 0.20) μm vs (0.66±0.14) μm,and the difference was statistically significant (t=-6.57,P＜0.01).Impedance baseline of esophagus and impedance recovery rate of patients with positive acid perfusion test were lower than those of patients with negative acid perfusion test,which were (2 755±680) Ωvs (3 411±536) Ω and (25.4±13.0) Ω minvs (33.4±9.8) Ω /min,and the differences were statistically significant (t =2.99,2.03;both P＜0.05).The correlation between impedance recovery rate and ICS was negative (r=-0.70,P＜0.01).Conclusions Recurrent reflux induced injury and delayed mucosal headline may be the factors of impaired mucosal integrity in patients with NERD.The changes esophageal of impedance baseline to a certain extent reflected the degree of esophageal mucosal integrity impairment.

Sunburn is an acute phototoxic reaction caused by excessive exposure of skin to solar ultravilet (UV) or artificial UV light sources. Studies show that sunburn is common in the general population, so that associated financial burden cannot be ignored. Meanwhile, sunburn at any age increases the risk of melanoma. Only by clarifying the influencing factors of sunburn can precise preventive measures be formulated. Although many studies have been conducted on the influencing factors of sunburn worldwide, there are great heterogeneity in reported influencing factors. In this paper, by means of systematic review, factors affecting sunburn were sorted out and summarized from four aspects, including demographic and socioeconomic characteristics, photosensitive phenotypes, UV-related environmental factors, and sun protection knowledge, attitude & behavior. Combined with population characteristics and data availability in China, our review provided reference for subsequent research and development of precise prevention and control strategies.