Objective To investigate the impact of high altitude on human gastric mucosa and its underlying mechanisms. Methods Twenty-five native Tibetans with chronic mountain sickness CMS residing at high altitude (4500 m) were examined for ultrastrueture and pathological changes of gastric mucosa. The other 25 native Tibetans residing at low altitude (＜2000 m) were served as control.The expression of hypoxia-inducible factor (HIF)-1α in human gastric mucosa was detected with immunohistochemistry. Results The color of gastric mucosa presented dark in patients with CMS.The histopathological examination showed significant differecnce in incidence of cnronc body gastritis and atrophic gastritis between CMS group and control group (P＜0. 05). The transmission electronic microscopy revealed that the epithlieal cells of gastric mucosa were impared in CMS group compared to control group. The expression of HIF-1α protein was increased in CMS group in comparison of control group (102.94± 34.04 vs 14.04 ± 6.53, P＜0.05). Conclusions The high altitude may involve in damage of gastric mucosa and the up-regulation of HIF-1α protein may involve in its mechanism.

Objective To analyze the etiological or associated factors and the treatment of patients with atrial fi brillation in high altitude areas in Tibet. Methods The clinical data of atrial fi brillation patients hospitalized in our hospital during January 2012 to Jane 2016 were analyzed retrospectively. Results (1) A total of 442 patients (male:female,1.2:1) were included in the study with ages of 30-96(65.9±12.3) years. The percentages of paroxysmal, persistent and permanent atrial fi brillation were 14.9%, 69.2%, and 15.8% respectively. The associated factors of atrial fi brillation included hypertension (53.4%), rheumatic heart disease (7.5%),chronic mountain sickness (10.6%), coronary heart disease(5.7%), hyperthyroidism (6.1%) and diabetes (9.0%).(2)Only 42 patients (9.5%) had evaluation with CHADS2score during hospitalization and actually 74.6% patients scored≥2. Twenty-one patients were restored to sinus rhythm during hospitalization and no patients had radiofrequency ablation.Conclusions The associated factors of atrial fi brillation in high altitude areas are similar to other areas. Thrombosis risk evaluation and anticoagulation therapy was not sufficient. Rhythm control rate was low and development of radio frequency ablation therapy should be considered.