Objective To observe periventricular white matter changes and matrix metalloproteinase-3 (MMP-3) expression after two-vessel occlusion in rats.Methods A total of 40 Wistar rats were randomly divided into four groups:sham operation group,model group 1 (20 days after operation),model group 2 (40 days after operation),model group 3 (60 days after operation)(n =10 per group).Model of chronic cerebral hypoperfusion was induced by permanent ligation of the bilateral common carotid arteries in the rat.The change of periventricular white matter was observed by electron microscope.The myelin basic protein (MBP) levels was determined by Western blotting,and the expression of MMP-3 was analysed by immunohistochemical stain and Western blotting.Results Permanent ligation of the bilateral common carotid arteries resulted in demyelination in the corpus callosum and internal capsule in rats.The expressions of MMP-3 in model groups were markedly elevated compared with sham group (model group 1,39.17± 4.167; model group 2,43.33±3.502; model group 3,54.16±2.787; sham group,26.67±3.830; all P＜0.01).The content of MBP in model groups was gradually decreased compared with sham group (model group 1,54.50±4.087; model group 2,47.83±4.875; model group 3,36.50±4.231; sham group,65.01±7.688; all P＜0.01).Additionally,the upregulation of MMP-3 had significant correlation with the loss of MBP in the periventricular white matter (r =-0.883,P＜0.01).Conclusions Chronic cerebral hypoperfusion induces progressive periventricular white matter demyelination,and the upregulation of MMP-3 may involve in the pathological process.

Objective To evaluate the efficacy of gait training and assessment system of Lokomat automatic robot (Lokomat robot) in patients with Parkinson's disease (PD).Methods Based on Hoehn-Yahr scale, 30 PD patients ranging from stage 2.5 to 3 were included and randomly assigned to Lokomat robot group ( n＝15) and control group ( n＝15).Lokomat robot system was employed in the training session of the Lokomat robot group, whereas patients in the control group were trained under auditory and visual guidance.Each training session lasted for 20 minutes, and repeated three days per week.Three motor assessments were performed before and after the four weeks training , including timed up and go test (TUGT), Unified Parkinson's Disease Rating Scale Ⅲ(UPDRS-Ⅲ) and three-dimensional gait analysis. Repeated measure analysis was performed under general linear mode , using SPSS 20.0.Results Gender, age, height and age of onset were matched in the Lokomat robot and the control groups .Scores of UPDRS-Ⅲ(Lokomat robot group , 23.46 ±2.72 vs 15.87 ±2.07; control group, 23.73 ±1.98 vs 18.07 ±0.80) and results of TUGT (Lokomat robot group, (15.42 ±5.59) vs (10.06 ±4.88) min; control group, (15.75 ± 4.67) vs (12.98 ±3.24) min) showed statistically significant differences before and after the gait training (UPDRS-Ⅲ, F＝258.598, P＝0.000; TUGT, F＝64.998, P＝0.000), and between the two groups (UPDRS-Ⅲ, F＝5.492, P＝0.026; TUGT, F＝6.522, P＝0.016).The step length (Lokomat robot group, (40.00 ±7.05) vs (52.70 ±7.62) cm; control group, (39.16 ±4.52) vs (46.72 ±7.29) cm), stride length (Lokomat robot group, (76.03 ±12.50) vs (90.60 ±12.46) cm; control group, (77.25 ± 8.07 ) vs (88.21 ±8.17) cm), walking pace ( Lokomat robot group, (67.16 ±12.79) vs (83.72 ± 10.96) m/min; control group, (65.35 ±11.56) vs (77.18 ±10.60) m/min), and total supporting phase (Lokomat robot group, 62.31% ±3.32% vs 56.05% ±3.98%; control group, 62.52% ±3.73% vs 57.96%±3.51%) showed significant improvement after training ( step length, F＝90.866, P＝0.000;stride length, F＝218.152, P＝0.000; walking pace, F＝172.236, P＝0.000; total supporting phase , F＝197.945, P＝0.000).Meanwhile, these improvements were more significant in the Lokomat robot group than the control group ( step length, F＝5.853, P＝0.022; stride length, F＝4.346, P＝0.046;walking pace, F＝4.904, P＝0.035; total supporting phase, F＝4.845, P＝0.036).No significant difference in step frequency was found before and after gait training.Conclusion Both gait trainings improved walking ability in PD patients , and Lokomat robot system guided training showed more obvious improvement than the traditional training under hearing and visual cue.

Objective:To analysis effectiveness of the "14 plus 7 day quarantine" and "nucleic acid plus total antibody testing" strategy (combined screening strategy) for screenin the imported patients with COVID-19 in Xiamen.Methods:The study populations were overseas travelers arriving in Xiamen from March 17 to December 31, 2020, and overseas travelers who had quarantine outside Xiamen for less than 21 days from July 18 to December 31, 2020. Data were collected and analyzed on the timing of detection, pathways, and test results of the imported patients with COVID-19 after implementing combined screening strategy.Results:A total of 304 imported patients with COVID-19 were found from 174 628 overseas travelers and 943 overseas travelers from other cities. A total of 163 cases (53.6%) were diagnosed by multitime, multisite intensive nucleic acid testing after positive finding in total antibody testing. Among them, 27 (8.9%) were first positive for nucleic acid in 14 plus 7 day quarantine and 136 were first positive for nucleic acid in 14-day quarantine. Only 8 of these individuals were tested positive for nucleic acid after positive total antibody testing. The other 128 individuals were tested positive for nucleic acid after being negative for average 2.3 times (maximum of 6 times). Aditional 155 cases might be detected by using the combined "14 plus 7 day quarantine" and " nucleic acid plus total antibody testing" strategy compared with "14-day quarantine and nucleic acid testing" strategy, accounting for 51.0% of the total inbound infections. So the combined screening strategy doubled the detection rate for imported patients with COVID-19. No second-generation case caused by overseas travelers had been reported in Xiamen as of February 26, 2021.Conclusions:Xiamen's combined screening strategy can effectively screen the imported patients with COVID-19 who were first positive for nucleic acid after 14 day quarantine. Compared with "14 day quarantine and nucleic acid testing", the combined screening strategy improved detection rate and further reduced the risk of the secondary transmission caused by the imported patients with COVID-19.