Objective To investigate the effect of hyperbaric oxygen intervention at different time on the neural stem cell proliferation and differentiation in dentate gyrus subgranular zone (SGZ) of adult rats after acute focal cerebral ischemia.Methods Totally 48 Sprague-Dawley male adult rats were randomly divided into a middle cerebral artery occlusion (MCAO) group, a hyperbaric oxygen group, a hyperbaric air group and a normobaric oxygen group, each of 12.A middle cerebral artery occlusion (MCAO) model was induced to all rats using the modified Zea-Longa's method of intraluminal filament occlusion, Except the MCAO group, the other 3 groups received corresponding hyperbaric oxygen, hyperbaric air and normobaric oxygen intervention once a day two hours after the suture insertion.The rats were sacrificed for double-label immunofluorescent analysis at 2 days, 3 days, 7 days and 14 days after brain ischemia.BrdU +/nestin + labeled the proliferated neural stem cells, and BrdU +/DCX + labeled its differentiated derivates, early neurons, in SGZ of ischemic hippocampus dentate gyrus.Also, the cell number was calculated under the fluorescence microscope.Results Two days after brain ischemia, the numbers of BrdU/nestin and BrdU/DCX cells in SGZ in the hyperbaric oxygen group were (2340.45 ± 1109.59) and (5520.66 ± 1103.09) respectively, which had increased significantly, compared with the hyperbaric air group and normobaric oxygen group (P ＜ 0.05).Three and 7 days after brain ischemia, the numbers of BrdU/nestin and BrdU/DCX cells in SGZ in the hyperbaric oxygen group had shown significant increase compared with the other 3 groups (P ＜ 0.05).Fourteen days after brain ischemia, the numbers of BrdU/DCX cells in SGZ in the hyperbaric oxygen group had significantly increased compared with the hyperbaric air group, normobaric oxygen group and the MCAO group (P ＜ 0.05).Conclusion Hyperbaric oxygen promotes the proliferation and differentiation of neural stem cells in ischemic SGZ.

Objective: To evaluate the accuracy and feasibility of coronary artery calcium score ( CACS) on virtual non-contrast scan ( VNC) images obtained from coronary artery CT angiography ( CCTA) scan with dual －layer spectral detector CT (SDCT) ． Methods : The data of 197 patients who underwent CCTA scan in hospital were analyzed retrospectively，and 88 patients with CACS ＞0 were further analyzed． Linear regression analysis of CACS and coronary artery calcium volume ( CACV) of true non-contrast (TNC) images and VNC images ( CACS-TNC， CACS-VNC，CACV-TNC，CACV-VNC) was performed to obtain linear regression equation and correction coefficients λ 1AVG and λ2AVG ．CACS-VNC and CACV-VNC were corrected by the corresponding regression equation and recorded as CCACS-VNC and CCACV-VNC，respectively．Spearman correlation coefficient was used for correlation analysis and Bland-Altman plot was used for consistency test．Mann-Whitney U test was used to compare the difference between the two groups. Results : For the total coronary artery，there was a strong correlation between CACS- TNC and CACS-VNC (rs = 0. 952，P ＜0. 001 ，λ 1AVG = 2. 19 ) ，CACV-TNC and CACV-VNC ( rs = 0. 954，P < 0. 001，λ2AVG = 1. 93) ．The results of Mann-Whitney U test showed that there was no significant difference between CACS-TNC and CCACS-VNC or between CACV-TNC and CCACV-VNC，and the Bland-Altman plot showed good consistency between CACS-TNC and CCACS-VNC ，CACV-TNC and CCACV-VNC． Conclusion VNC images based on SDCT can accurately measure CACS and be used for cardiovascular risk classification，which is expected to replace TNC scan and reduce the radiation dose of patients.