Objective To observe the expression of the polysialic acid neural cell adhesion molecule ( PSA-NCAM) in the hippocampus of rats after exposure to low intensity ( 16 Hz,90 dB) infrasound for different periods.Methods One hundred and twenty male Sprague-Dawley rats were randomly divided into infrasound exposure and normal groups.The exposure group was tjem further divided into 1 day,7 days,14 days and 21 days exposure groups.After exposure,the rats' brains were removed and an immunohistochemical technique was used to observe the expression of PSA-NCAM in the hippocampus after 1,7,14 or 21 days of exposure. Methods The expression of PSA-NCAM had increased significantly after exposure for 7 days. It peaked at 14 days,then had decreased by 21 days,but always remaining higher than in the normal group.After the infrasound exposure had ended,the expression of PSA-NCAM demonstrated a tendency of decrease over time,and the least was on the 21st day.The largest decrease was observed in the 14 days exposure groups. Conclusion 16 Hz,90 dB infrasound can increase the expression of PSA-NCAM in the hippocampus,at least in rats.This suggests that low intensity infrasound might initiate recovery of an injured central nervous system.Migration of neural stem cells may aid in the repair of neural injuries resulted from infrasound exposure.

Objective To compare the different therapeutic efficacies between radiofrequency and cryoballoon ablation in atrial fibrillation(AF)patients with enlarged left atrium.Methods A total of 106 AF patients with enlarged left atrium(LAVI)>34ml/m2 who visited our center between December 2016 and May 2022 for catheter ablation were enrolled.They were divided into radiofrequency group(R-group)and cryoballoon group(C-group)according to the procedure.The recurrence of AF was compared between the two groups.Results The median follow-up time was 12 months and no death occurred.The rate of loss of follow-up was 3.8%.The overall recurrence rate of AF after ablation was 36.8%.There was no significant difference in clinical baseline between the two groups(P>0.05).The radiofrequency group had longer operation time(P<0.001),shorter X-ray time and less exposure(P<0.05);There was no significant difference in clinical baseline and postoperative complications between the two groups(P>0.05).The results of survival analysis showed that there was no significant difference in the survival rate of patients without atrial fibrillation/atrial flutter/atrial tachycardia between the two groups(P>0.05).Conclusion For AF patients with enlarged left atrium,the clinical effects of the two methods were similar.Cryoballoon takes a shorter time,while radiofrequency has a lower X-ray time and exposure dose for physicians and patients.Therefore,appropriate ablation methods should be selected according to the actual situation.