Objective To observe characteristics of the activity in resting brain of asymptomatic reflux esophagitis (RE) patients,and explore the role of default network in the pathogenesis of asymptomatic RE.Methods Functional magnetic resonance imaging (fMRI) was performed to scan the brains of 15 asymptomatic RE patients,15 symptomatic RE patients and 15 healthy volunteers under no-mission-stimulation state.With fractional amplitude of low frequency fluctuation (fALFF),characteristics of the strengthened and weakened regions of asymptomatic RE patients,symptomatic RE patients and healthy individuals were compared and analyzed.SPM 5 was applied for data preprocessing.Single-sample t test was performed to observe the noticeable active regions of each group under resting state,and then double-sample t test was used to compare the characteristics of active regions of the entire brain between asymptomatic RE patients and symptomatic RE patients or healthy individuals.Results Under resting state,the active brain regions of asymptomatic RE patients,symptomatic RE patients and healthy individuals were similar.The activity of only small part of brain regions in visceral sensory processing relevant networks changed.There was no significant difference in the active regions of default network under resting state between asymptomatic RE patients and healthy individuals.Compared with symptomatic RE patients,fALEF decreased at right central sulcus cover,right superior temporal gyrus,right insula,right transverse temporal gyrus,right postcentral gyrus,superior temporal gyrus and temporal pole (X=50,Y=-6,Z=12,t=2.7874,P＜0.01).Conclusion The difference in characteristics of activity in default network under resting state may play an important role in the pathogenesis of asymptomatic RE.

A large spontaneous mass on the dorsal abdomen near the hip joint was found in an aged female Tupaia belangeri subsp. yaoshanensis after 5 years of routine feeding. The tumor in the diseased tree shrew was huge, with an intact surface and no ulceration; however, it caused inconvenience in movement while maintaining a good mental state. After inhalation anesthesia with isoflurane (2%-4%), the tree shrew was euthanized after the tree shrew entered deep anesthesia. Anatomical dissection of the tumor, the tumor boundary was unclear and infiltrated into surrounding tissues. HE staining showed that small focal pleomorphism and large areas of adipocytes were seen in the tumor tissue. The pleomorphic sarcoma area was mainly composed of atypical epithelioid cells with easily visible nuclear divisions. The size of the adipocytes was significantly different, and more pleomorphic adipocytes were seen. The cell volume was large, the nucleus was deeply stained and deformed, the edge was impressed, and the cytoplasm was seen with multiple vesicular lipid droplets. Immunohistochemical results showed that the tumor cells were positive for Vimentin, the small focal polymorphic adipocyte nucleus was positive for S-100, and Ki-67 exhibited a higher proportion of positivity. Combined with HE staining and immunohistochemical results, the spontaneous tumor in this tree shrew was comprehensively diagnosed as pleomorphic liposarcoma.