Weanling rats were fed with a low-selenium diet (Se 0.009mg/kg, — Se group) and the diet supplemented with sodium selenite (Se 0. 232mg/kg,+ Se group) for 1, 2 and 3 months respectively. The generation rate of superoxide radical(O_2~-), activity of manganese dependent superoxide dismutase (Mn-SOD) in heart mitochondria and blood Se concentration from the rats were determined. The results showed that the mitochondrial O_2~- generation rate from — Se rats was significantly higher than those from + Se rats at 2 and 3 months. During all the feeding periods, no significant difference in mitochondrial Mn-SOD activity was found between the—Se and + Se groups,while the blood Se concentration in — Se group was significantly lower than those in + Se group at each feeding time and continually decreased in the 2 and 3 month. The results suggested that selenium could depress O_2~- generation in heart mitochondria.

Objective To investigate the clinical significance of combined heart and lung ultrasound in patients with severe left heart failure and pulmonary hypertension. Methods From March 2016 to June 2017, 75 patients with grade Ⅲ and Ⅳ heart failure and dyspnea were enrolled in Qingdao Municipal Hospital Affiliated to Qingdao University. Thirty-three patients had normal pulmonary artery pressure (normal pulmonary arterial pressure group), 25 patients had mild pulmonary hypertension (mild pulmonary hypertension group), and 17 patients had moderate to severe pulmonary hypertension (moderate to severe pulmonary hypertension group). The patient′s plasma B-type natriuretic peptide (BNP) was measured. Left ventricular diameter (LVD), right ventricular diameter (RVD), and left ventricular ejection fraction (LVEF) were measured by echocardiography. The patient′s lungs were observed by lung ultrasonography, and its number was recorded. One-way analysis of variance was used to compare the differences of LVD, RVD, and LVEF in three groups of patients with severe left heart failure. Further comparison between groups was performed using LSD-t test. Kruskal-wallis H test was used to compare the plasma BNP concentration and B-line number in three groups of patients with severe left heart failure. The Mann-Whitney U test was used to further compare the groups. The receiver operating characteristic (ROC) curve of pulmonary hypertension diagnosed by plasma BNP concentration and B line number in patients with severe left heart failure were drwan. Results The concentrations of BNP in patients with normal pulmonary arterial pressure, mild pulmonary hypertension, and moderate to severe pulmonary hypertension were 890 (614, 1516), 1460 (1245, 1950), and 2660 (1670, 3279) ng/L, respectively. The number of B line was 12 (9, 16), 17 (14, 18), 26 (20, 28), and the RVD was (22.1±1.7), (24.9±2.0), (26.3±2.8) mm, respectively. The number of B-line and RVD in the moderate-severe pulmonary hypertension group were both lager than those in the mild pulmonary hypertension group, and the number of B-line and RVD in the mild pulmonary hypertension group were both lager than those in the normal pulmonary artery pressure group. There was significant difference between any two groups (BNP concentration: U=210.500, P < 0.05; U=47.000, 73.000, both P < 0.001;B line number:U=189.000,P < 0.05;U=38.5000,64.000,both P < 0.001;RVD:t=0.553, 0.623, both P<0.001; t=0.656, P<0.05). There was no significant difference in LVD and LVEF between the three groups of patients. The ROC curve showed that the optimal threshold for the diagnosis of pulmonary hypertension in patients with severe left heart failure with BNP concentration was 1225 ng/L. The sensitivity was 85.7%,the specificity was 69.7%,the area under the curve was 0.814,and the 95% CI was 0.717 to 0.911. The optimal threshold for diagnosis of pulmonary hypertension in patients with severe left heart failure was B line number 14, the sensitivity was 88.1%, specificity was 66.7%, the area under the curve was 0.836, and 95%CI was 0.747 to 0.925.Conclusion Patients with severe left heart failure at different pulmonary artery pressure levels have different B-line findings, and the number of B-line increases with the severity of pulmonary hypertension, which warrants further study and application.

Objective: To evaluate the efficacy of dynamic locking screw combined with plate internal fixation for tibial fractures. Methods: A retrospective case-control study was conducted to analyze the clinical data of 36 patients with tibial fractures (AO 4A-C) admitted to the Second Affiliated Hospital of Army Medical University from March 2017 to March 2018. There were 27 males and nine females, aged 26-71 years [(51.6±14.3)years]. A total of 18 patients were treated with dynamic locking screw combined with locking plate internal fixation (Group A), and another 18 patients received common locking screw combined with locking plate internal fixation (Group B). The operation time, intraoperative bleeding, hospital stay, visual analogue score (VAS), callus growth and fracture healing rate at 4, 8, 12 and 24 weeks after operation were compared between the two groups. At the same time, the complications of internal fixation were evaluated, including screw loosening, screw fracture and steel plate fracture. Results: All the patients were followed up for 8-18 months [(12.2±2.7)months]. There was no significant difference in operation time, intraoperative bleeding, postoperative hospital stay and postoperative VAS between the two groups (P>0.05). At 8 and 12 weeks after operation, the callus growth rate of Group A was 61% and 83% respectively, significantly higher than those of Group B (28% and 50%) (P<0.05). At 8, 12, and 24 weeks after operation, the fracture healing rate of Group A was 17%, 50% and 100% respectively, and those of Group B was 6%, 28% and 89%, showing no significant difference between the two groups (P>0.05). No complications or failure of internal fixation were found during the follow-up. Conclusion For tibial fractures, the locking plate internal fixation can achieve satisfactory clinical outcome, but the dynamic locking screw system can promote the growth of callus at early stage.