Objective To investigate the effect of ERK1/2 phosphorylation on the proliferation of human aorta vascular smooth muscle cells (HAVSMCs) stimulated by advanced glycation end products (AGEs) Methods CCK8 was used to test the effect of AGEs with different concentration on the proliferation of HAVSMCs, and the effect of PD98059, a specific inhibitor of ERK1/2, on HAVSMCs proliferation stimulated by AGEs was also detected. Flow Cytometer (FCM) was used to detect the cell cycle transformation induced by AGEs. Western Blot was used to detect the expression of relative proteins. Results 10 mg/L AGEs observably facilitated the proliferation and the DNA synthesis of HAVSMCs and PD98059 (40 umol/L) markedly inhibited the proliferation and cell cycle evolution of HAVSMCs induced by AGEs. Furthermore, ERK1/2 phosphorylation, and PCNA were regulated by AGEs and thus it showed time and dose dependent. Conclusion AGEs participates in the proliferation of HAVSMCs by activating ERK1/2 signal path.

Skeleton metabolic diseases such as osteoporosis and fracture have posed an detrimental impact on the elderly, which is a primary cause of paralysis and even death in patients. Osteoblast and osteoclast are the two major parts in the regulation of bone homeostasis and imbalance of these two cells, which may result in dysfunction of bone metabolism. Recent researches indicated that bone homeostasis was primarily regulated by endocrine, paracrine, and local mechanical processes. However, increasing evidences have indicated that the significant role of nerve system may involve in bone metabolism via both central and peripheral pathways. Neuropeptide Y(NPY), a neurotransmitter that belongs to a family of peptides,serves as a critical hinge connecting nerve system and skeleton system. Several studies have suggested that NPY generated by both central and peripheral nerve system could regulate bone homeostasis and that NPY-energic nerve fibers distributed on bone surface and in intramedullary cavity and NPY receptors located at osteoblast, chondrocyte, and osteocytes also provide a basis for nerve-skeleton metabolic pathways. NPY can directly regulate osteoprogenitor, involving in the production and differentiation of osteoblast and osteoclast. In addition, as a pivotal molecular of energy homeostasis, NPY may affect glucose and fat homeostasis. Studies of animal models also have further indicated energy metabolism may directly or indirectly participate in the regulation of bone mass. Therefore, further researches on the relationship between NPY and bone homeostasis may facilitate to unveil the central and peripheral regulatory effect of NPY on bone homeostasis and provide a new sight for the treatment of skeleton metabolism-related diseases in the future.

Objective To evaluate the effect of hydromorphone postconditioning on the electrophysiological stability during ischemia-reperfusion (I/R) in isolated rat hearts.Methods Healthy adult male Sprague-Dawley rats,aged 2-3 months,weighing 280-360 g,were heparinized and anesthetized with pentobarbital sodium.Their hearts were excised and perfused in a Langendorff apparatus with K-H solution saturated with 95％ O2-5％ CO2 at 37 ℃.Twenty-four Langendorff-perfused hearts were divided into 3 groups (n =8 each) using a random number table:control group (group C),I/R group and hydromorphone postconditioning group (group HM).The isolated hearts were subjected to 60 min ischemia followed by 60 min reperfusion to establish the model of isolated heart I/R injury.The isolated hearts were perfused with K-H solution containing 4.1 ng/ml hydromorphone for 10 min starting from onset of reperfusion in group HM.Heart rate,electrocardiogram,coronary flow,and monophasic action potential amplitude,in the left ventricular endocardium,mid-myocardium and epicardium the maximal increase rate (Vmax) at the 0 phase,and monophasic action potential duration at 50％ and 90％ repolarization (MAPD50 and MAPD90,respectively) were recorded at 20 min of stabilization (T0) and 10,25,40 and 60 min of reperfusion (T1-4).The transmural dispersion of repolarization (TDR) was calculated,and the time for restoratiou of spontaneous heart beat was recorded.Results There was no significant difference in the heart rate,coronary flow or monophasic action potential amplitude between the three groups (P＞0.05).Compared with group C,V in the epieardium was significantly decreased,MAPD50 and MAPD90 in the three transmural layers were prolonged,and TDR was prolonged in group I/R (P＜0.05).Compared with group I/R,the time for restoration of spontaneous heart beat,MAPD50 in the endoeardium and mid-myocardium,and MAPD90 and TDR in the endocardium were significantly shortened (P＜0.05),and no significant change was found in V in group HM (P＞0.05).Conclusion Hydromorphone postconditioning is helpful in maintaining the electrophysiological stability during I/R in isolated rat hearts.

Objective To evaluate the role of δ-opioid receptors in hydromorphone postcondition-ing-induced maintenance of electrophysiological stability during ischemia-reperfusion(I∕R)in isolated rat hearts. Methods Healthy male Sprague-Dawley rats, aged 2-3 months, weighing 280-360 g, were used in this study. The animals were anesthetized with intraperitoneal pentobarbital 60 mg∕kg. Their hearts were immediately removed and perfused in a Langendorff apparatus. Thirty-two isolated hearts were divided into 4 groups after successful preparation of Langendorff perfusion model(n=8 each)using a random number ta-ble: control group(group C), group I∕R, hydromorphone postconditioning group(group HP)and hydro-morphone plus δ-opioid receptor antagonist naltridole postconditioning group(group HNP). In HP and HNP groups, the hearts were perfused for 10 min with K-H solution containing 41 ng∕ml hydromorphone and 41 ng∕ml hydromorphone plus 5 μmol∕L naltridole, respectively, and then with K-H solution for 50 min. At 20 min of stabilization(T0)and 10, 25 and 60 min of reperfusion(T1-2), heart rate(HR), monophasic action potential(MAP)duration at 90% repolarization(MAPD90)of the two layers(endocar-dium, epicardium)of the anterior left ventricular wall were recorded. Transmural dispersion of repolariza-tion(TDR)was calculated. The development of arrhythmia, time for restoration of spontaneous heart beat and duration of arrhythmia were recorded during the period of reperfusion. Results Compared with group C, MAPD90of endocardium at T1-2and MAPD90of epicardium at T1were significantly prolonged in I∕R and HP groups, HR was significantly decreased at T2-3, MAPD90of endocardium and epicardium was prolonged at T1-3in group HNP, TDR was significantly enlarged at T1in group I∕R and at T2in group HNP, and TDR was decreased at T3in group HP(P<005). Compared with group I∕R, no significant change was found in arrhythmia score(P>005), the time for restoration of spontaneous heart beat was significantly shortened, and TDR was decreased at T1in HP and HNP groups, duration of arrhythmia was significantly shortened, and MAPD90of endocardium was shortened at T1in group HP, and HR was significantly decreased at T2-3, MAPD90of endocardium and epicardium was prolonged at T1-3, and TDR was decreased at T2-3in group HNP(P<005). Compared with group HP, no significant change was found in time for restoration of spon-taneous heart beat, duration of arrhythmia or arrhythmia score(P>005), HR was significantly decreased at T2-3, MAPD90of endocardium and epicardium was prolonged at T1-3, and TDR was increased at T3in group HNP(P<005). Conclusion The mechanism underlying hydromorphone postconditioning-induced maintenance of electrophysiological stability during I∕R is related to activating δ-opioid receptors in isolated rat hearts.

Objective: To investigate the application of the flipped classroom based on micro-class versus traditional class in animal surgery teaching, and to provide new thinkings for animal surgery teaching. Methods: A total of 120 undergraduates from Navy Medical University were randomly divided into control group (class A) and experimental group (class B). The students in class A received traditional teaching, and those in class B received flipped classroom teaching. Questionnaire survey and course assessment were performed after teaching, and a comparative analysis was also performed. Results: The self-assessment survey showed that 88.3%, 73.3%, 71.6%, 48.3%, and 73.3% of the students in class A (traditional teaching) filled in the questionnaire with "Very Helpful and Helpful", while 91.7%, 85.0%, 83.3%, 78.3%, and 75.0% of the students in class B (flipped classroom teaching) filled in with "Very Helpful and Helpful"; class B gave better overall evaluation of teaching model than that of class A. The mean total score of class B was 0.91, higher than that of class A (8.43 vs. 7.52, P<0.05), and the mean total score of examination papers in class B was 10.92, higher than that in class A (101.13 vs. 90.21, P<0.05). Conclusion Flipped classroom based on micro-class could improve the teaching effect of debridement course on animal surgery and increase students' self-learning ability.

Objective:To evaluate the test-retest reliability of MRI criteria in the 2019 Bosniak classification of cystic renal masses (CRMs) and to analyze the impact of lesions′ property, size and readers′ experience on the test-retest reliability.Methods:From January 2009 to June 2019, 207 patients with 207 CRMs were included in this retrospective study. All of them underwent renal MRI and surgical-pathologic examination. According to Bosniak classification, version 2019, all CRMs were independently classified twice by eight radiologists with different levels of experience. All radiologists were blinded to the pathology of the lesions. By using intraclass correlation coefficient (ICC), test-retest reliability was evaluated for all CRMs and for subgroups with different pathological properties (benign and malignant) and different sizes (≤40 mm and>40 mm). The test-retest reliability of 4 senior readers (≥10 years of experience) and 4 junior readers (<10 years of experience) were evaluated respectively. The comparison of ICC was performed using Z test. Results:The 207 CRMs included 111 benign lesions (83 benign cysts, 28 benign tumors) and 96 malignant tumors. There were 87 lesions with maximum diameter ≤40 mm and 120 with maximum diameter>40 mm. The test-retest reliability (ICC) of each reader for all lesions was 0.776-0.888, the overall ICC was 0.848 (95%CI 0.821-0.872). The ICCs of senior and junior readers were 0.853 (95%CI 0.824-0.880) and 0.843 (95%CI 0.811-0.871) respectively, without significant difference between the two groups ( Z=0.85, P=0.374). The ICC of all readers was 0.827 for benign lesions and 0.654 for malignant lesions, showing significant difference ( Z=2.80, P=0.005). The ICC was 0.770 for lesions ≤40 mm and 0.876 for lesions>40 mm, which was significantly different ( Z=-2.36, P=0.018). For CRM subgroups with different pathological properties and different sizes, there was no significant difference in test-retest reliability between senior and junior readers (all P>0.05). Conclusion:The test-retest reliability of MRI criteria in the 2019 Bosniak classification of CRMs is excellent and unaffected by readers′ experience. The reliabilities are not consistent among CRMs of different pathological properties and different sizes, but all reached the level of good and above.