Problem—based Learning(PBL) fit well with characteristic of military foreign medical students and the peculiarity of preventive medicine.In order to improve the self-studying and problem-solving ability of foreign students,attention should be paid to several key points to PBL,such as teaching content selection,informationization teaching tool application and teacher cultivation etc.

Designed experiment teaching fits well with characteristic of naval hygiene training subjects on the sea.Attention should be paid to several key points including content selection,training plan design and teaching effect evaluation.It was proved that designed experiments enhanced the practical ability of the undergraduates and significantly improved the effect of naval hygiene training subjects.

Objective: To observe the changes of free amino acids (FAAs) in plasma and brain of rats during simulated sea sickness and post–adaptation. Method: Pica or kaolin consumption was used as an indicator to judge the development of sea sickness and adaptation when SD rats were stimulated by Crampton sea sickness simulator. FAAs concentrations in plasma and brain of rats were determined by high performance liquid chromatography (HPLC) after simulated sea sickness and post-adaptation. Results: After simulated sea sickness stimulation for 1 d, the levels of Cys and Ile were increased, and Gly and Pro decreased significantly in plasma. The increase of BCAA/AAA ratio was also found. In brain, the contents of Ala, Cys+Met, Tyr, His, and total amino acids were remarkably decreased. After simulated sea sickness stimulation for 21 d, no changes of FAAs were observed in plasma and brain but the ratio of Glu/ GABA was increased in brain. There were no differences of FAAs, Glu/GABA ratio and BCAA/AAA ratio in plasma and brain of tolerant and susceptible sea sickness rats. Conclusion: The levels of amino acids, especially those related to neurotransmitter synthesis, in plasma and brain were changed significantly during sea sickness.

Objective This paper was performed to investigate the effectiveness of problem-based learning in naval hygiene teaching. Methods Totally 257 clinical medicine undergraduates and general practice undergraduates from Grade 2010 and 2009, Faculty of Naval Medicine, Second Military Medical University attended naval hygiene teaching. PBL and LBL approaches were applied in PBL group (Grade 2010, n=117) and LBL group (Grade 2009, n=140), respectively. The learning outcomes were evaluated by three tests covering PBL evaluation (or usually performance), theoretical examination and experimental practice . Questionnaire was used to investigate the recognition of PBL teaching method and new evaluation system. Data were analyzed by SPSS 16.0 and t test was used to compare the average scores of theory,α=0.05. Results The results showed that the average theory scores of Grade 2010 (78.51±7.57 and 71.68±5.74) were higher than those of Grade 2009 (65.36±6.41 and 59.97±7.08) (P=0.000, P=0.000). The questionnaire surveys indicated that more than 85% students in PBL group considered the PBL teaching method could enhance professional and comprehensive quali-ties, and that 84%students were satisfied with new evaluation system. Conclusions PBL showed better learning results than traditional methods in naval hygiene teaching and could better promoted students' comprehensive ability.

Objective To investigate the related factors of the prognosis of arterial embolectomy of acute cardiogenic cerebral embolism caused by atrial fibrillation.Methods The clinical data of using vein thrombolysis bridging artery embolectomy or arterial embolectomy alone for the treatment of patients with acute cardiogenic cerebral embolism of cerebral large artery occlusion due to atrial fibrillation were analyzed retrospectively.From January 2015 to December 2016,22 consecutive inpatients with cardioembolic cerebral embolism caused by paroxysmal or persistent atrial fibrillation were enrolled,including 10 patients with the 90-day modified Rankin Scale (mRS) score 0-2 (good recovery group) and 12 patients with mRS scores 3-6 (poor recovery group).The clinical features,imaging data,and treatment of the patients in both groups were compared.The factors such as age,gender,preoperative international standardization ratio (INR),embolism position,whether bridging vein thrombolysis before thrombectomy,National Institutes of Health Stroke Scale (NIHSS) score at the onset,time of onset to reperfusion (TOR),whether using tirofiban,times of thrombectomy,modified Thrombolysis In Cerebral Infarction (mTICI) blood flow grade,and postoperative intracranial symptomatic intracerebral hemorrhage were analyzed.Results There were no significant differences in age,gender,preoperative INR,embolism position,the number of intravenous thrombolysis before thrombectomy,the number of using tirofiban in surgery,the proportion of the above mTICI 2b grade,and the proportion of symptomatic cerebral hemorrhage after surgery of the patients between the two groups (P>0.05).The NIHSS score 15.2±2.0 at the onset in the good recovery group was lower than 22.9±8.4 in the poor recovery group.There was significant difference between the two groups (P<0.05).The TOR time (307±86 min) in the good recovery group was less than that of the poor recovery group (426±145 min).There was significant difference between the two groups (P<0.05).Embolectomy was performed 1.5 (0.5,3.0) times in the good recovery group,which was less than the poor recovery group (4.0 [2.0,7.0] times).There was significant difference between the two groups (P<0.05).Conclusions Shortening the time of reperfusion and reducing the number of embolectomy during operation are the important factors for improving the prognosis of patients when atrial fibrillation causes arterial embolectomy in patients with acute cerebral embolism.However,a study of larger sample is needed for further exploration.

Objective To investigate and analyze clinical obstetrics and gynecology clinicians' mastery of basic skills, and then find the way to help clinicians master basic clinical skills. Methods A self-designed questionnaire survey was conducted among 310 clinicians working in 1-3 grade hospital from Chongqing, Sichuan, Guizhou, Yunnan provinces anonymously by spot field investigation and letter-investigations from February 1, 2015 and to March 31, 2015. The data were analyzed by descriptive analysis, using SPSS 19.0 software package for rank sum test analysis. Result Among 310 valid questionnaires, 31.6% (98) clinicians considered having inadequate clinical skills, 26% (81) average and 42.3%(131) expert. All the basic skills obtained had a relationship with the number of operations, working years and professional title. Most of the basic clinical skills were from working in hospitals 85% (270), journal 82% (254), academic conference 58% (174); 94.2% (293) willing to participate in training classes like clinical teaching and training in moulds. Conclusion The gynecology and obstet-rics basic clinical skills have a great relationship with basic skills training. Providing opportunities for the basic clinical skill trainings, academic conferences, in-service education and establishing regional medical source sharing platform can enhance their clinical skills.

Iatrogenic gastrointestinal perforation is one of the severe adverse events of endoscopic therapeutic procedure. For acute iatrogenic perforation,management by endoscopic techniques is a simple and rapid modality to close the perforation with minimal invasiveness and avoiding the traditional surgical trauma. Endoclips,suture with special instruments,covered stents,degradable sheets combined with tissue adhesive,and combined endoscopic techniques such as snares combined with endoclips,are the major endoscopic therapeutic modalities for closure of iatrogenic gastrointestinal perforation. In this article,the current status and progress of endoscopic management for acute iatrogenic gastrointestinal perforation were reviewed.

Objective To investigate the relationship between the evaluation of cerebral perfusion with CT perfusion (CTP)imaging and cognitive impairment in patients with asymptomatic severe internal carotid stenosis. Methods A total of 104 patients with asymptomatic severe unilateral internal carotid artery origin stenosis (the unilateral stenosis rate ≥70% and the contralateral stenosis rate < 30%)were enrolled respectively. After conducting Montreal Cognitive Assessment (MoCA)scores,they were divided into a non-cognitive impairment group (n = 24;MoCA ≥26)and a cognitive impairment group (n = 80;MoCA <26). All patients were performed digital subtraction angiography (DSA)and / or CT angiography (CTA)examinations. Their unilateral severe stenosis was confirmed,and they underwent brain CTP examinations. The relative cerebral blood flow (rCBF),relative cerebral blood volume (rCBV),relative mean transit time (rMTT),and relative time to peak (rTTP)were calculate by CTP. The presence rate of collateral circulation in 96 patients was calculated by DSA. The presence rate of collateral circulation,and relative perfusion parameters of the 2 groups were compared. Results (1)The MoCA score in patients of the non-cognitive impairment group was 27. 8 ± 1. 7,and the MoCA score in patients of the cognitive impairment group was 21. 4 ± 3. 1. There was significant difference between the 2 groups (t = 17. 959, P <0. 05). (2)The rate of 96 patients having collateral circulation was 68. 4% (52 / 76)in the cognitive impairment group,and in the non-cognitive impairment group was 60. 0% (12/ 20). There was no significant difference (P >0. 05). The CTP parameters rMTT,rTTP,rCBV,and rCBF in the non-cognitive impairment group were 1. 074 ± 0. 066,1. 103 ± 0. 032,1. 045 ± 0. 021 and 1. 066 ± 0. 040,respectively;the CTP parameters rMTT,rTTP,rCBV,and rCBF in the cognitive impairment group were 1. 241 ± 0. 169, 1. 328 ± 0. 248,1. 046 ± 0. 030,and 1. 093 ± 0. 058,respectively. The rTTP and rMTT of the cognitive impairment were longer than those of the non-cognitive impairment group. There were significant differences in rTTP and rMTT between the 2 groups (P < 0. 05),but there were no significant differences in rCBF and rCBV between the 2 groups (P >0.05). Conclusion Most of the patients with asymptomatic severe internal carotid stenosis has cognitive impairment,and cerebral perfusion caused by stenosis is significantly slower in patients with cognitive impairment than in those with noncognitive impairment.

Objective To investigate the efficacy and safety of covered stent in treatment of esophageal perforation. Methods Observe and analyzed the effect and complications of covered metallic stent in esophageal perforation. In all of 40 cases, the most common causes were iatrogenic, esophageal cancer, and foreign body. Results All patients with esophageal perforation got successful esophageal stent placement. All of them recovered smoothly in eating. The stents were removed 4 days to 1 month later. Gastroscopy and angiography confirmed esophageal perforation has healed. 3 cases of esophageal cancer patients with dysphagia obviously relieved after stent placement. The main complications in stent and stent migration for chest pain after operation. 6 cases (15 %) of patients with stent displacement, while 2 cases (5 %) of esophageal cancer patients with food obstruction and stent displacement. Conclusion Treatment of esophageal perforation with covered metal stents endoscopically is effective and safe.

Objective To investigate the clinical characteristics of cognitive impairment in the patients with asymptomatic unilateral severe internal carotid artery stenosis (ICAS). Methods A total of 80 patients with unilateral severe carotid stenosis (stenosis rate ≥70%)and 40 patients without carotid stenosis (control group)diagnosed by digital substract angiography (DSA)were analyzed retrospectively. According to the stenotic sides,the patients with severe ICAS were divided into a left stenosis group and a right stenosis group (n = 40 in each group). The North American Symptomatic Carotid Endarterectomy Trial (NASCET)criteria were used to grade the degree of stenosis. Montreal cognitive assessment (MoCA)was used to evaluate the cognitive function of the patients,and then the cognitive function of the patients in 3 groups was assessed. Results The MoCA total scores,visuospatial and executive functions,and language ability,and delayed memory scores of the patients in both left and right groups were lower than those of the control group. There were significant differences (21. 8 ± 3. 1,3. 4 ± 1. 3,1. 8 ± 0. 6,and 1. 6 ± 1. 3,respec-tively in the left stenosis group;22. 6 ± 2. 5,3. 5 ± 1. 1,1. 9 ± 0. 6,and 1. 7 ± 1. 4,respectively in the right stenosis group;and 26. 4 ± 1. 8,4. 2 ± 0. 9,2. 7 ± 0. 6,and 3. 8 ± 1. 0,respectively in the control group;all P < 0. 01). There were no significant differences in naming,attention,abstract ability,orientation ability scores compared with the control group (all P > 0. 05). There were no significant differences in the MoCA total scores and each single test score of the patients between the left stenosis and the right stenosis groups (P > 0. 05). Conclusion The patients with asymptomatic unilateral severe ICAS have cognitive impairment generally;it is characterized by delay memory,visuospatial and executive functions,and language dysfunction.