The medical education of China and the United States was compared by analyzing the differences about educational system, teaching mode and teaching content in this paper. Standard-ization of the Chinese medical education system, improving clinical practice, teaching students by initi-ating questions and advanced medical education technology were recommended in China. This paper will inspirit and provide experience for the innovation of Chinese medical education.

Objective To evaluate the role of spinal dopamine D2 receptors in a rat model of neuropathic pain.Methods Thirty healthy male Sprague-Dawley rats,aged 6-8 weeks,weighing 180-200 g,wcre randomly divided into 5 groups (n =6 each) using a random number table:control group (group C),sham operation group (group S),neuropathic pain group (group NP),normal saline group (group N) and dopamine D2 receptor agonist quinpirole group (group Q).Neuropathic pain was produced by chronic constriction injury of the sciatic nerve (CCI) in rats anesthetized with intraperitoneal 2％ pentobarbital sodium 40 mg/kg.At 7 days after CCI,normal saline 10 μl was injected intrathecally over 30 s in group N,and quinpirole 10 μg (in 10 μl of normal saline) was injected intrathecally over 30 s in group Q.At 1 day before CCI,3 and 7 days aher CCI,and 30 min and 1,2,4,8 and 16 h after administration,mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured.Results There was no significant difference in MWT and TWL at each time point between group C and group S.MWT was significantly lower,and TWL was shorter at T1-8 in NP,N and Q groups than in C and S groups.Compared with group N,no significant change was found in MWT and TWL at each time point in N group,and MWT was significantly increased,and TWL was prolonged at T4-6 in group Q.Conclusion Inhibited function of spinal dopamine D2 receptors is involved in the maintenance of neuropathic pain in rats.

Objective To investigate clinical distribution and drug sensitivity of infectious pathogens in our wards for hematology malignancies. Methods Drug sensitivity tests of bacteria were performed by Kirby-Bauer method, 56 strains of pathogens were isolated from all detected samples. Results The results showed that the composition ratio of Gram-negtive bacteria, Gram-positive bacteria was 69.64%, 30.36%. In decreasing frequency, Escherichia coli (37.50%), Klebsiella pneumoniae (10.71%). All of staphylococcies were resistant to meticillin, and sensitive to vancomycin. Conclusion This study indicates that Gramnegative bacteria remain the predominant pathogens in microorganisms causing bloodstream infections for hematological malignancies at Huashan Hospital. The incidence of Escherichia coli is the highest. All of staphylococcies were resistant to meticillin.

Objective To select sonogram features for the differential diagnosis of benign and malignant thyroid small nodules by Logistics regression analysis,and to contribute the binary Logistic regression model of sonogram features as independent variable and evaluate the value of conventional ultrasonography and ultrasound elastography (UE) in the differential diagnosis of benign and malignant thyroid small nodules.Methods 166 thyroid nodules (≤ 10 mm) in 140 patients were reviewed and analyzed by 2D ultrasound,color Doppler flow imaging and UE.A Logistic model was obtained based on pathology as golden diagnosis criteria.The odds ratio of variables in the equation were compared to assess various variables,especially the efficacy of elastography in the diagnosis.Results Four statistically significant features were finally entering the Logistic stepwise regression model,including shape,calcification,the internal component of nodules and elasticity score.And the odds ratio of the elasticity score was higher than other features.Conclusions The analysis of binary Logistic regression can select the valuable variables for the diagnosis of pathological nature of thyroid small nodules.UE has much more dominances than other features.The combinated application of UE and 2D ultrasonic features plays a great clinical role in the final diagnosis of thyroid small nodules.

Objective To investigate whether two-dimension speckle tracking imaging(2D-STI) and ICAM-1-targeted myocardial contrast echocardiography could detect the acute cellular rejection of heart transplantation at the early stage.Methods The abdominal heterotopic heart transplantation model was successfully established using Wistar and SD rats.Forty-eight rats were divided into allografts (ALLO) group (n =24) and isografts(ISO) group (n =24).Echocardiography,2D-STI and ICAM-1 targeted myocardial contrast echocardiography were performed at 1,3,5 day after transplantation respectively.After ultrasound imaging,transplanted hearts were harvested for Hematoxylin-eosin staining and immunofluorescence histochemistry to evaluate acute cellular rejection and ICAM-1 expression.Results There were obvious difference between ALLO group and ISO group in echocardiographic parameters at 5 days after transplantation surgery (all P ＜0.05).Compared with those in ISO group,global circumferential strain and strain rate (GCS,GCSr),and circumferential strain of endo-myocardium (CSendo) decreased in ALLO group at day 3 post-transplantation (all P＜0.05).Compared with those in ISO group,all strain parameters in ALLO decreased significantly at postoperative day 5 (all P＜ 0.05).Myocardial contrast echocardiography using ICAM-1-targeted microbubbles showed that the video intensity in ALLO group was significant higher than that in ISO group at postoperative day 3 and day 5 (all P＜0.05).Conclusions 2D-STI and myocardial contrast echocardiography using ICAM-1-targeted microbubbles are sensitive and useful for detecting heart transplant acute rejection at the early stage.

Objective To evaluate the effect of pharmacological postconditioning on longitudinal myocardial function in rabbits' model of myocardial inshemia-reperfusion using layer-specific strain of ultrasound speckle tracking imaging.Methods Forty healthy rabbits were randomly divided into two groups:ischemia-reperfusion group (IR) and pharmacological postconditioning group (ATP-PPost). Echocardiography examinations were performed at baseline,45 min after ligation and 30 min,60 min,120 min after reperfusion.Pathological examinations were applied in two rabbits randomly selected from each group at 45 min after ligation and 30 min,60 min after reperfusion and at the end of experiment.Results①After coronary artery ligation,left ventricular ejection fraction (LVEF) decreased in two groups(P <0.05) and longitudinal systolic strain(SLsys) of 3 myocardial layers decreased in two groups (P <0.01). And the SLsys in the endocardium had greater variation than that in the epicardium.②Compared with that after ligation,the SLsys of all myocardial layers increased at 30 min after reperfusion in ATP-PPost group (P <0.01),and the SLsys in endocardial layer kept increasing with the time of reperfusion(P <0.05). And the SLsys of 3 myocardial layers were significantly higher in ATP-PPost group than those in IR group (P <0.01).③ In two groups,the values of SLsys were decreasing from endocardial layer to epicardial layer.They were higher in the endocardium than those in the epicardium at any time(P <0.01 and P <0.05).Conclusions Layer-specific strain of STI can evaluate exactly the regional myocardial function of rabbit myocardial pharmacological-postconditioning model.SLsys of endocardial layer is more sensitive to myocardial ischemia than that of epicardial layer.

Objective To investigate the application value of shear wave elastography (SWE) combined with superb micro-vascular imaging (SMI) in differentiating malignant and benign thyroid masses.Methods Seventy-eight patients diagnosed by ultrasound and verified with postoperative pathological analysis were enrolled.Conventional two-dimensional ultrasound was applied to observe the masses.SWE was performed to evaluate the elasticity and the Young's modulus (AveT1) value acquired.ROC curve was drawn to calculate the sensibility and specificity using the cut-off value of AveT1.SMI was applied to define Adler's grading standard according to the degree of blood supply.The sensitivity,specificity and accuracy of SWE and SWE combined with SMI in differentiating malignant and benign thyroid masses were analyzed.Results ①According to pathological analysis,there were 42 benign and 44 malignant masses;②The AveT1 value between malignant and benign groups were all significantly different (P ＜0.01).41.4 kPa was used as the best cut-off value of AveT1.The area under the ROC curve were 0.83 with sensitivity 86.9％ and specificity 88.1％;③There were more masses with the Alder class Ⅱ-Ⅲ in malignant group than those in benign group,and the difference was statistically significant (P ＜0.01);④Quantified with SWE or SWE combined with SMI,the sensitivity were 86.9％ and 91.3％,specificity were 88.1％ and 92.8％,and accuracy were 87.5％ and 94.1 ％,respectively,and the difference was statistically significant (P ＜ 0.01).Conclusions SWE combined with SMI represents an excellent application value in differentiating malignant and benign thyroid masses,which could improve the sensitivity,specificity and accuracy of the diagnosis for thyroid masses using ultrasound.

Objective To explore the diagnostic value of thyroglobulin measurement with fine‐needle aspiration ( FNA‐Tg ) in detecting papillary thyroid carcinoma ( PTC ) metastatic lymph nodes ,and analyze the impact of different factors on the diagnostic accuracy of FNA‐Tg . Methods One hundred and fifty‐four lymph nodes from 138 patients w ho underwent total thyroidectomy and cervical lymphadenectomy were enrolled . Ultrasonography ,fine needle aspiration cytology ( FNAC) and FNA‐Tg results were acquired in all patients . T he diagnostic value of FNAC ,FNA‐Tg and the combination of the two methods were compared in suspicious PTC metastatic lymph nodes . T he influence of lymph nodes size ,lymph nodes cystic change and serum thyroglobulin antibody( TgAb) on the accuracy of FNAC and FNA‐Tg were analyzed . Results T he sensitivities of FNAC ,FNA‐Tg ,and the combination of the two methods in the diagnosis were 79 .5% , 95 .5% and 97 .7% ,respectively . T he specificities were 100% ,93 .9% and 100% ,respectively . T he size and cystic change of lymph nodes had effects on the accuracy of FNAC( P ＜0 .05) ,w hile they had no effect on the accuracy of FNA‐Tg ( P ＝0 .42 ,0 .67 ) . T he serum TgAb level had no influence on the accuracy of FNAC and FNA‐Tg ( P ＝ 0 .88 ,0 .34 ) . Conclusions FNA‐Tg is sensitive to metastatic lymph nodes in PTC w hich not affected by the lymph nodes size ,the lymph nodes cystic change and serum TgAb level . Application of FNA‐Tg with FNAC can improve the sensitivity of diagnosis ,w hich is important in the diagnosis of PTC metastatic lymph nodes .

Objective To observe the impact factors of the diagnostic accuracy of fine needle aspiration biopsy(FNAB)for papillary thyroid carcinoma(PTC).Methods Totally 468 patients with single PTC confirmed by postoperative pathology who underwent FNAB before surgery were enrolled.The impact of clinica,l ultrasonic and pathological features on the accuracy of FNAB diagnosis were analyzed.Results The accuracy of FNAB for diagnosing PTC was 71.37%(334/468).The maximum diameter and location of PTC were both impact factors of the diagnostic accuracy of FNAB.The maximum diameter of 0.7 cm was the optimal cutoff value of FNAB for diagnosing PTC,and the diagnostic accuracy of FNAB for PTC with the maximum diameter＜0.7 cm and those≥0.7 cm was 62.96%(119/189)and 77.06%(215/279),respectively.The diagnostic accuracy of FNAB for PTC located in the difficult and easy area of puncture was 52.53%(52/99)and 76.42%(282/369),respectively.The diagnostic accuracy of FNAB for PTC with the maximum diameter≥0.7 cm and located in the easy area,≥0.7 cm and located in the difficult area,＜0.7 cm and located in the easy area,＜0.7 cm and located in the difficult area was 80.43%(185/230),61.22%(30/49),69.78%(97/139)and 44.00%(22/50),respectively.Conclusion The maximum diameter and location of PTC were both impact factors of the diagnostic accuracy of FNAB.