Simulation-based medical education can ensure medical safety, reduce medical errors and improve students' clinical skills. At present, the main problems in medical teaching are the conflict between doctors and patients, the contradiction between medical teaching and ethics, the shortage of teaching resources and the lack of a universal assessment standard. The advantages of simulation-based medical education are its safety, repeatability, standardization, controllability, relative authenticity, and the cultivation of humanistic spirit and teamwork for students. Simulation-based medical education has two major limits. First, its teaching effect relies on the function and quality of each model. Second, simulation cannot replace clinical practice. This article proposes the following ways and means for promoting the simulation-based medical education: training of faculty is the core, establishment of courses is the focus, cooperation and communication is an important way to promote development, and phased and refined development is the future direction.

Objective To explore the viscoelasticity of relaxed myocardium in vivo through indentation method with an intervention ultrasound indentation system (IUIS). Methods Old myocardial infarction (OMI) models of canine were established by ligating left anterior descending branch of coronary artery for 3 months. The indentation creep tests were used respectively in OMI group and shame group (n=8, each) by IUIS in middle and advanced diastole stage in vivo. Test data were processed with three-parameter solid viscoelasticity model, and the viscoelastic parameters, such as instantaneous elastic modulus (E1), relaxation modulus (E∞), creep elastic modulus (E2) and viscous damping coefficient (η) in normal and infarcted myocardium were obtained and compared. Results All the parameters of E1, E∞, E2 and η increased obviously in OMI group than in sham group shown as follows: 27.81±6.74kPa vs. 6.78±2.43kPa; 17.87±3.59kPa vs. 4.52±1.56kPa; 49.54±14.35kPa vs. 16.82±12.37kPa and 1.97±0.78Pa.s vs. 0.66±0.40Pa.s. The differences were statistically significant (P<0.05). Conclusions IUIS is a feasible method to assess the viscoelasticity of relaxed myocardium in vivo. Three-parameter viscoelasticity model can be used to describe creep properties of relaxed myocardium. Both elastic modulus and viscosity resistance have increased in infarcted myocardium.

Objective To evaluate the effects of dexmedetomidine on the oxidative stress responses during global cerebral ischemia-reperfusion (I/R) in rats.Methods Thirty-six male Sprague-Dawley rats,weighing 250-300 g,were randomly divided into 3 groups (n =12 each) using a random number table:sham operation group (group S),global cerebral I/R group (group I/R) and dexmedetomidine group (group D).Global cerebral ischemia was induced by occlusion of bilateral common carotid arteries combined with hypotension (MAP maintained at 35-45 mmHg).In group D,dexmedetomidine was infused at a rate of 3 μg · kg-1 · h-1until 2 h of reperfusion after a loading dose of dexmedetomidine 3 μg/kg was intravenously injected immediately after onset of reperfusion.The neurological deficit score (NDS) was assessed at 24 h of reperfusion,the rats were then sacrificed,and their brains were immediately removed for determination of cell apoptosis and levels of malondialdehyde (MDA),superoxide dismutase (SOD) and catalase (CAT).Apoptotic rate was calculated.Results Compared with group S,NDS,apoptotic rate and MDA level were significantly increased,and SOD and CAT levels were decreased in I/R and D groups.Compared with group I/R,NDS,apoptotic rate and MDA level were significantly decreased,and SOD and CAT levels were increased in group D.Conclusion Dexmedetomidine attenuates global cerebral I/R injury through inhibiting the oxidative stress responses.

Objective Investigate the reasonable surgical approach combined with frozen sections pathological features of papillary thyroid microcarcinoma.Methods Clinical data of 96 cases papillary thyroid microcarcinoma nearly 5 years of follow-up in our clinic referral was retrospectively analyzed.Metastasis and recurrence rate were compared between group of ipsilateral lobe plus isthmus resection (unilateral group) and group of ipsilateral lobe plus isthmus resection and contralateral lobe subtotal (bilateral group).Metastasis and recurrence rate were compared between group of central lymph node dissection (dissection group) and non-dissection group (non-dissection group),and the injury rate of the recurrent laryngeal nerve was also compared between the two groups.Results The diagnosis of cancer by intraoperative frozen pathology were 53 cases (55％).Whether in high or low risk populations,the metastasis and recurrence between unilateral and bilateral groups showed no significant difference (P ＞ 0.05).Whether in high or low risk populations,the metastasis and recurrence between dissection group and non-dissection groups showed no significant difference (P ＞0.05).The temporary injury rate of recurrent laryngeal nerve in dissection group were higher than thatin non-dissection group both in high-risk populations (P =0.040,P ＜ 0.05) and low risk populations(P =0.037,P ＜ 0.05).Conclusions Intraoperative frozen pathological diagnosis of papillary thyroid microcarcinoma is difficult.The reasonable surgical approach for the first time is ipsilateral lobe plus isthmus resection.Preventive cervical dissections operation should not be carried out if the exploratory of lymph node showed no metastasis.

PURPOSE: Synuclein-gamma (SNCG), which was initially identified as breast cancer specific gene 1, is highly expressed in advanced breast cancers, but not in normal or benign breast tissue. This study aimed to evaluate the effects of SNCG siRNA-treatment on breast cancer cells and elucidate the associated mechanisms. METHODS: Vectors containing SNCG and negative control (NC) siRNAs were transfected into MDA-MB-231 cells; mRNA levels were determined by real-time polymerase chain reaction. Cell proliferation was evaluated using the MTT assay, cell migration was assessed by the Transwell assay, apoptosis and cell cycle analyses were conducted with the flow cytometer, and Western blot analysis was performed to determine the relative levels of AKT, ERK, p-AKT, and p-ERK expression. RESULTS: SNCG mRNA levels were significantly reduced in MDA-MB-231 cells transfected with SNCG siRNA. Our results indicate that in SNCG siRNA-treated cells, cell migration and proliferation decreased significantly, apoptosis was induced, and the cell cycle was arrested. Western blot analysis indicated that the protein levels of p-AKT and p-ERK were much lower in the SNCG siRNA-treated groups, than in the control and NC groups. CONCLUSION: SNCG siRNA could decrease the migration and proliferation of breast cancer cells by downregulating the phosphorylation of AKT and ERK.
Apoptosis ; Blotting, Western ; Breast ; Breast Neoplasms ; Cell Cycle ; Cell Migration Assays ; Cell Movement* ; Cell Proliferation ; Extracellular Signal-Regulated MAP Kinases ; Phosphorylation* ; Proto-Oncogene Proteins c-akt ; Real-Time Polymerase Chain Reaction ; RNA, Messenger ; RNA, Small Interfering ; Synucleins*

Objective To evaluate the effects of dexmedetomidine on the permeability of blood-brain barrier in rats subjected to global cerebral ischemia-reperfusion (I/R).Methods Thirty-six male Sprague-Dawley rats,weighing 250-300 g,were randomly divided into 3 groups (n =12 each):sham operation group (group S),global cerebral I/R group (group I/R) and dexmedetomidine group (group D).Global cerebral I/R was induced by occlusion of bilateral common carotid arteries combined with hypotension (MAP was maintained at 35-45 mm Hg) in anesthetized rats.In group D,dexmedetomidine was infused at a rate of 3μg· kg-1 · h-1 until 2 h of reperfusion after a loading dose of dexmedetomidine 3 μg/kg was injected intravenously immediately after onset of I/R.The rats were sacrificed at 24 h of reperfusion and their brains were immediately removed for microscopic examination of hippocampal CA1 region and for determination of the cell apoptosis,brain water content,Evans blue content and aquaporin 4 (AQP4) expression.Results The number of apoptotic cells was significantly larger,and brain water content,Evans blue content and AQP4 expression were higher in groups I/R and D than in group S (P ＜ 0.05 or 0.01).The number of apoptotic cells was significantly smaller,and brain water content,and Evans blue content and AQP4 expression were lower in group D than in group I/R (P ＜ 0.05 or 0.01).Global cerebral I/R-induced pathological changes were significantly attenuated in group D.Conclusion Dexmedetomidine can decrease the permeability of blood-brain barrier and attenuate global cerebral I/R injury in rats,and down-regulation of AQP4 expression may be involved in the mechanism.

Objective To investigate the effects of dexmedetomidine on global cerebral ischemia-reperfusion (I/R) injury in rats.Methods Fifty-four adult male SD rats weighing 200-250 g were randomly divided into 3 groups (n =18 each): shame operation group (group S),global cerebral I/R group (group I/R) and dexmedetomidine group (group D).Global cerebral I/R was produced by occlusion of bilateral common carotid arteries combined with hypotension (MAP maintained at 35-45 mm Hg).In group D dexmedetomidine 3 μg/kg was injected iv immediately after I/R,followed by infusion of dexmedetomidine at a rate of 3 μg· kg- 1 · h- 1 until 2 h of reperfusion.The neurological deficit score (NDS) was assessed (0 =normal,100 =brain death) at 6 h (T1),24 h (T2)and 72 h (T3) of reperfusion.Then six rats were sacrificed in each group and brain tissues were removed for microscopic examination of hippocampus CA1 region and determination of activity of myeloperoxidase (MPO),contents of TNF-α and IL-1β and expression of glial fibrillary acidic protein ( GFAP).Results Compared with group S,NDS,MPO activity and the contents of TNF-α and IL-1β at T1-3 were significantly increased,the expression of GFAP was up-regulated at T2,3 in groups I/R and D ( P ＜ 0.05 or 0.01).Compared with group I/R,NDS,MPO activity and TNF-α concent were significantly decreased at T1-3,IL-1β concent was decreased at T1,2,the expression of GFAP was down-regulated at T2,3 in group D (P ＜ 0.05 or 0.01 ).The pathologic changes were significantly attenuated in group D as compared with group I/R.Conclusion Dexmedetomidine can attenuate global cerebral I/R injury in rats,and the inhibition of inflammatory response may be involved in the mechanism.

Objective To investigate the effect of lipoxin A4(LXA4) on inflammatory response in a rat model of permanent focal cerebral ischemia (PFCI). Methods Seventy-two adult male SD rats weighing 200-250 g were randomly divided into 3 groups (n = 24 each):group Ⅰ sham operation (group S); group Ⅱ PFCI and group Ⅲ LXA4. PFCI was induced by thread occlusion of right middle cerebral artery according to the method described by Longa in group Ⅱ and Ⅲ. In group Ⅲ LXA4 100 ng/5 μl was injected into right ventricle of the brain after PFCI was successfully induced, while in group Ⅰ and Ⅱ equal volume of normal saline was injected instead of LXA4. Six animals were killed at 6, 12 and 24 h of ischemia. Their brains were immediately removed for microscopic examination and determination of myeloperoxidase (MPO) activity, TNF-α, IL-10 and transforming growth factor-β1 (TGF-β1) contents in the ischemic cortex. The expression of glial fibrillary acidic protein (GFAP)was measured by immuno-histochemistry. Apoptosis in neurons was assessed using TUNEL. Results PFCI significantly increased MPO activity, TNF-α, IL-10 and TGF-β1 contents and GFAP expression in the ischemic cortex and neuronal apoptosis in group Ⅱ as compared with group S. LXA4 significanfly decreased MPO activity,TNF-α content, GFAP expression and neuronal apoptosis and increased IL-10, TGF-β1 contents at 12,24 h of ischemia. LXA4 significantly ameliorated PFCI-induced cerebral histopathologic damage. Conclusion LXA4 can protect the brain against PFCI injury by inhibiting inflammatory response.

Objective To investigate the mechanism of endothelin (ET) in acute biliary pancretitis (ABP)with renal impairment, and examine the improvement of renal function by puerarin. Methods Thirty-two patients of ABP with renal impairment were selected and were randomly divided into group A and group B. Group A were given puerarin post-operatively, while group B were given common manegement postoperatively. Meanwhile, 16 ABP patients without renal impairment were selected as group C, and 16 nonABP patients who had common hepatic or biliary diseases were selected as group D. The levels of plsma ETand creatinine clearance rate(Ccr) of renal function in each group were observed pre-operation and 1 week post operation. Results In pre-operation the ET level in group A, B and C were higher than in group D(P ＜0.001), and the ET level in group A,B was higher than in group C(P＜0.001). Post operation after I week the ET level in group A was lower than in group B(P =0.014), while the Ccr level in group A was higher thanin group B ( P = 0.002). Conclusions The function of endothelin is an important mechanism in biliary pancretitis with renal impairment. Puerarin might reduce the ET level and increase the Ccr level in patients of ABP with renal impairment, improve the renal function of such patients.

Objective To investigate the effect of lipoxin A4 ( LXA4 ) on the permeability of blood-brain barrier (BBB) after focal cerebral ischemia-repeffnsion (I/R) in rats. Methods Fifty-four adult male SD rats weighing 200-250 g were randomly divided into 3 groups ( n = 18 each): group Ⅰ sham operation (group S); group Ⅱ focal cerebral I/R ( group I/R) and group Ⅲ LXA4 ( group L). Focal cerebral I/R was produced by middle cerebral artery occlusion (MCAO) with a 4-0 nylon thread with rounded tip inserted into right internal jugular vein and threaded cranially in group Ⅱ and Ⅲ . In group Ⅲ LXA4 100 ng was injected into right lateral ventricle of the brain after MCA was successfully occluded. MCAO was maintained for 2 h. The neurological deficit was evaluated and scored (0 = no deficit, 5 = death) at 24 h of reperfusion. 2% Evans blue 4 ml/kg was injected via femoral vein at 1 h before the animals were sacrificed. The animals were killed and their brains were immediately removed for determination of brain water content, Evans blue content and expression of matrix metalloproteinase-9 (MMP-9)in the ischemic cortex. Results The neurologic deficit scores, the brain water and Evans blue content and MMP-9 protein expression in the cortex were significantly higher in I/R group than in S group. The cerebral I/R-induced changes were significantly attenuated in LXA4 group. Conclusion LXA4 can protect blood-brain barrier against cerebral I/R injury by inhibiting MMP-9 protein expression in the brain tissue.