Objective To investigate the difference of matrix stiffness in different regions of tibial plateau in osteoarthritis (OA) and its effects on morphology of the cartilage and mitochondria. Methods The tibial plateau cartilage specimens of OA were obtained for nanoindentation test, transmission electron microscopy and histological analysis. The stiffness of cartilage matrix in different regions of OA tibial plateau was detected by nano-indentation. The morphology of cartilage mitochondria in different regions was observed by transmission electron microscopy, and the changes of mitochondrial plane area, shape and ridge volume density were quantitatively analyzed. Cartilage injury in different regions of OA tibial plateau was observed by histological staining. Results The cartilage of OA tibial plateau showed regional heterogeneity, and the cartilage and mitochondria on medial side of varus knee OA were more severe, and the matrix stiffness was higher. The OA scores were positively correlated with matrix stiffness. There was also a significant correlation between OA scores and mitochondrial morphology: the higher OA scores, the larger and rounder mitochondrial plane area, and the lower cristae volume density. Conclusions The differences of tibial plateau revealed the correlation between cartilage matrix stiffness, OA scores and mitochondrial morphological parameters. The increased cartilage matrix stiffness may be the main cause of chondrocyte mitochondrial injury, and further aggravate the progression of OA.

Objective:To construct three image recognition models of manikin′s glottis using visual laryngoscopy based on deep-learning algorithm.Methods:The tracheal intubation manikin′s epiglottis was visualized using a videolaryngoscope, and then epiglottis was elevated to expose the glottis and acquire glottic images. A total of 149 images were obtained from various angles and orientations and randomly divided into training set and test set, and the annotation of image data was completed. Three glottal image recognition models of CenterNet, YOLOv3 and YOLOv4 were developed. The training set was used to complete the training of the models, and finally the test set was used to evaluate the model performance.Results:CenterNet, YOLOv3 and YOLOv4 three models were successfully constructed, the mean average precision of CenterNet, YOLOv3 and YOLOv4 was 92.33%, 89.52% and 89.02% respectively, the recall rates were 87.50%, 90.00% and 90.00% respectively, the precision rates reached 97.22%, 94.74% and 94.74% respectively, and the accuracy rates were 90.91%, 85.11% and 88.89% respectively. All three algorithms demonstrated an identical F1 score of 91.00%.Conclusions:The CenterNet, YOLOv3 and YOLOv4 models are successfully constructed, and three recognition models can accurately identify the glottis in the image, with the CenterNet model demonstrating the highest recognition precision.

Objective:To develop a novel, flexible, dual-arm, master-slave digestive endoscopic minimally invasive surgical robot system named dual-arm robotic endoscopic assistant for minimally invasive surgery (DREAMS) and to evaluate its feasibility for endoscopic submucosal dissection (ESD) by using ex vivo porcine stomachs.Methods:A novel endoscopic robot (DREAMS) system was developed which was composed of a flexible two-channel endoscope, two flexible robotic manipulators, a master controller, a robotic arm, and a control system. A total of 10 artificial round-like lesions with diameters ranging from 15 to 25 mm were created (5 in gastric antrum and 5 in gastric body) by using fresh peeled stomach of healthy pigs as the model. Submucosal dissection was performed with the assistance of the DREAMS system by two operators. The main outcome was submucosal dissection speed, and the secondary outcomes included muscular injury rate, perforation rate, and grasping efficiency of the robot.Results:All 10 lesions were successfully dissected en bloc by using the DREAMS system. The diameter of the artificial lesions was 22.34±2.39 mm, dissection time was 15.00±8.90 min, submucosal dissection speed was 141.79±79.12 mm 2/min, and the number of tractions required by each ESD was 4.2 times. Muscular injury occurred in 4/10 cases of ESD. No perforation occurred. Conclusion:The initial animal experiment shows the DREAMS system is safe and effective.

Marinesco-Sj?gren syndrome (MSS), also known as hereditary ataxia-dwarf-mental retardation syndrome, is a rare autosomal recessive ataxia syndrome. This article reviews the recent advance in clinic characteristics, pathogenic gene mutation sites, pathogenesis and clinic diagnosis and treatment of MSS, in order to improve clinicians' understanding of the disease and diagnosis and treatment level, and reduce the missed diagnosis and misdiagnosis of the disease.

Objective:To investigate the current status of satisfaction with training program and loyalty to the university among professional postgraduate students majoring in clinical medicine, as well as the association between satisfaction with training program and loyalty to the university.Methods:The 2017 National Medical Student Satisfaction Survey Database was used. A total of 1 944 professional postgraduate students in the second or third year, as well as those with delayed graduation, from 59 postgraduate training colleges and universities who participated in clinical internship were selected. SPSS 20.0 software was used for analysis; descriptive analysis was used to describe satisfaction with training program and loyalty to the university; factor analysis was adopted to calculate comprehensive satisfaction score to reduce the number of variables; logistic regression analysis was applied to investigate the association of general information and satisfaction with training program with loyalty to the university.Results:The professional postgraduate students majoring in clinical medicine had a degree of 60.44% of loyalty to the university. Satisfaction with training program reflected low satisfaction at each link of the training program. For every 1-point increase in the comprehensive satisfaction scores of the four links of courses, research training, college support, and practice, the loyalty to the university was increased to 2.11, 1.83, 1.77, and 1.75 times as the original, respectively, of the baseline scores.Conclusion:There is still room for further improvement in the satisfaction with training program and the loyalty to the university among professional postgraduate students majoring in clinical medicine, and the satisfaction with training program is closely associated with the loyalty to the university. Colleges and universities need to take measures for courses, practice, research training, and college support, so as to improve satisfaction and thus enhance loyalty to the university.

Objective:To study the expression and value of inflammatory factors and disease activity in dry eyes of rheumatoid arthritis patients.Methods:From March 2017 to November 2019, 78 patients with rheumatoid arthritis complicated with dry eye diagnosed by the rheumatology department of our hospital, 80 patients with simple dry eye treated in the ophthalmology clinic and 80 normal volunteers were collected. All subjects were examined for OSDI questionnaire scores, tear film rupture time (BUT), tear secretion test (SIT), and corneal fluorescein staining (FL) scores. Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), rheumatoid factor (RF) and other disease activity-related indicators were collected. The concentrations of interleukin-1b (il-1b), tumor necrosis factor-a (tnf-a), chemokine 3(CCL3), CCL4, CCL5, and vascular endothelial growth factor (VEGF) in the collected tears were detected by double-antibody sandwich enzyme-linked immunosorbent assay (ELISA). One-way Anova was used to analyze the correlative indexes among the three groups, LSD- t method was used for multiple comparison. Pearson's method was used to analyze the correlation between Ra activity and dry eye. Results:The results of OSDI [(44±9) points vs (44±9) points vs (24±7) points], SIT [(3.3±2.2) mm/5 min vs (3.6±2.1) mm/5 min vs (11.7±1.6) mm/5 min], BUT [(4.3±1.8) s vs (5.9±1.9) s vs (10.4±2.0) s], FL [(7.3±3.1) points vs (5.7±2.8) points vs (1.6±1.6) points] were com-pared among the three groups. There were significant differences among the three groups( F=154.22, P<0.01; F=470.49, P<0.01; F=217.72, P<0.01; F=101.99, P<0.01). The concentrations of IL-1β [(1.92±0.14) ng/L vs (1.28±0.18) ng/L vs (0.64±0.15) ng/L], IL-6 [(38.24±0.69) ng/L vs (36.31±0.82) ng/L vs (30.43±0.87) ng/L]、TNF-α [(0.78±0.03) ng/L vs (0.67±0.03) ng/L vs (0.56±0.02) ng/L], CCL3 [(91±25) ng/L vs (83±21) ng/L vs (24±18) ng/L], CCL4 [(187±76) ng/L vs (137±64) ng/L vs (37±5) ng/L], CCL5[(259±70) ng/L vs (182±42) ng/L vs (135±34) ng/L] and VEGF [(172±25) ng/L vs (152±22) ng/L vs (41±21) ng/L] in the tears of the three groups were significantly different( F=1 300.15, P<0.01; F=2 036.37, P<0.01; F=1 305.89, P<0.01; F=764.01, P<0.01; F=225.47, P<0.01; F=138.48, P<0.01; F=121.04, P<0.01). The indexes of disease activity (ESR, CRP, RF) were compared among the three groups. The positive rate of RF[(100%) vs (5%) vs (4%)] was significantly higher in Ra dry eye group than in the other two groups ( χ2=127.38, P<0.01) There were significant differences in ESR[(51±23) mm/1 h vs (9±4) mm/1 h vs (8±5) mm/1 h] and CRP[(44±23) g/L vs (5±4) g/L vs (6±4) g/L] among the three groups ( F=253.18, P<0.01; F=222.36, P<0.01) . BUT was negatively correlated with the activity index (ESR, CRP, RF) in rheumatoid arthritis dry eye group ( r=-0.398, P=0.005; r=-0.353, P=0.010; r=-0.302, P=0.038) , FL was positively correlated with activity index (ESR, CRP, RF) ( r=0.345, P=0.014; r=0.385, P=0.007; r=0.412, P=0.003) . There was no correlation between SIT, OSDI and activity index (ESR, CRP, RF)( r=-0.265, P=0.060; r=-0.156, P=0.318; r=-0.275, P=0.070); ( r=-0.087, P=0.582、 r=-0.065, P=0.664; r=-0.045, P=0.768). Conclusion:Inflammatory factors and disease activity indexes are highly expressed in rheumatoid arthritis patients with dry eye of disease, and there is a correlation between disease activity of rheumatoid arthritis and dry eye, which has some clinical meaing.

Objectives? To describe the human resource allocation of ophthalmic nurses in China, and to compare the differences based on the ophthalmic nurse availability among different regions so as to put forward policy recommendations. Methods? We used the latest data of China Ophthalmic Competency Resource Survey in 2015 and China Population and Employment Statistics Yearbook to describe the quantity, education backgrounds and professional titles of ophthalmology nurses in different regions of China. Population-weighted quartiles of the county-level number were defined and used to analyze the differences in education backgrounds and professional titles among different regions and different levels of availability. Results? By the end of 2014, the number of ophthalmic nurses was 3.19 per 100 000. The eastern part had 30% more nurses than the western and the urban area had 285% more than the rural area. The ratio of ophthalmology doctors to ophthalmic nurses is 1∶1.13 while the eastern area had the lowest ratio. Most of the ophthalmic nurses held post-secondary diploma and only entry-level titles. The availability of ophthalmic nurses in the east China was better than any other parts. It was easier to get an ophthalmic nurse in the cities than in rural areas. And the condition got worst in western rural districts. The proportion of nurses with a bachelor's degree went higher with the increase in availability, while this trend reverted with regard to the proportion of senior titled nurses. With the same availability, the quality of human resources in western and rural areas is the worst. Conclusions? The resource allocation of ophthalmic nurses in China has gradually improved, but there are still problems such as regional inequality and large urban-rural gap. The availability analysis can show the inter-regional difference in terms of the quantity of ophthalmic nurses in a more detailed manner, such that the situations in the urban and rural areas are in extremely differentiated states; The quality of ophthalmic nurses in China needs to be further improved, and the quality difference will further aggravate the imbalance of resource allocation.

OBJECTIVE:To establish the method for the simultaneous determination of content of 6 active components as neochlorogenic acid,mulberroside A,chlorogenic acid,astragalin,sanggenon C and morusin in Morus alba,and to provide reference for improving quality control standard of M. alba. METHODS:HPLC method was adopted. The determination was performed on Agilent 5 TC-C18with mobile phase consisted of acetonitrile-0.1% formic acid(gradient elution)at the flow rate of 1 mL/min. The detection wavelength of 280 nm. RESULTS:The mass concentration linear range of neochlorogenic acid, mulberroside A,chlorogenic acid,astragalin,sanggenon C and morusin were 0.001 06-0.042 4,0.001 67-0.066 8,0.007 95-0.318, 0.001 65-0.066 0,0.005 00-0.200 and 0.001 24-0.049 6 mg/mL,respectively(all r≥0.999 6);the limits of quantitation were 0.11, 0.14,0.81,0.17,0.45 and 0.12 μg/mL,respectively;the limits of detection were 0.04,0.05,0.41,0.07,0.18 and 0.04 μg/mL, respectively;RSDs of precision test were 0.26%,0.31%,0.24%,0.27%,0.36% and 0.44%(n=6),respectively;RSDs of stability test were 0.68%,0.54%,0.62%,0.53%,0.41% and 0.73%(n=6),respectively;average method recovery rates were 99.1%,98.8%,98.8%,98.4%,98.5% and 99.9%(RSDs were 0.5%-1.5%,n=9),respectively. CONCLUSIONS:The method is simple,accurate,and can be used for simultaneous determination of 6 active components in M.alba.

BACKGROUND: Previous studies have found that skeletal muscle satellite cell transplantation can induce angiogenesisin myocardial infarction area, reduce infarct size and improve cardiac function. But the overall effect is not satisfactory.OBJECTIVE: To observe the survival of basic fibroblast growth factor (bFGF) gene modified skeletal muscle satellitecells in acute myocardial infarction and to observe the expression of bFGF gene and the effect of cell transplantation onangiogenesis in myocardial infarction area.METHODS: Eighteen New Zealand white rabbits were divided into three groups by random: skeletal muscle satellite cellgroup (control group), bFGF gene enhanced skeletal muscle satellite cell group (experimental group) and blank controlgroup. The left anterior descending branch of the coronary artery of the rabbits was ligated so as to establish an animalmodel of acute myocardial infarction in the former two groups. After labeled by DAPI before transplantation, the skeletalmuscle satellite cells, bFGF gene modified skeletal muscle satellite cells and the equivalent amount of DMEM/F12 wereinjected into the local infarct myocardium correspondingly. Samples were taken 4 weeks after transplantation. Then, thesurvival of skeletal muscle satellite cells and the expression of bFGF gene were observed under light microscope andfluorescence microscope, and the neovascularization in the myocardial infarction area was examined byimmunohistochemical staining.RESULTS AND CONCLUSION: No DAPI-labeled cells were visible in the blank control group, but in the other twogroups, a large amount of DAPI-labeled skeletal muscle satellite cells were seen in the infarction area. Enhanced greenfluorescent protein was highly expressed in the experimental group. Microvessel density in the infarction area washighest in the experimental group followed by the control and blank control groups (P < 0.05). These findings indicatethat bFGF gene modified skeletal muscle satellite cells can survive and promote neovascularization in the acutemyocardial infarction area.

Objective To evaluate the effect of dezocine on the c-fos expression in neurons in the midbrain periaqueductal gray in a rat model of incisional pain.Methods Thirty-six pathogen-free healthy adult male Wistar rats,weighing 250-300 g,were divided into 3 groups (n =12 each) using a random number table:control group (group C),incisional pain group (group I) and dezocine group (group D).A 1 cm longitudinal incision was made through skin,fascia and muscle of the plantar aspect of the right hind paw in sevoflurane-anesthetized rats.In group C,the rats were only anesthetized and underwent no operation.In group I,0.9％ sodium chloride solution 2 ml was injected via the caudal vein at 15 min before the model was established.In group D,dezocine 1 mg/kg (diluted to 2 ml in 0.9％ sodium chloride solution) was injected via the caudal vein at 15 min before the model was established.At 24 h before operation (T0) and 2,6 and 24 h after operation (T1-3),the mechanical paw withdrawal threshold (MWT) and cumulative pain score were measured.After measurement of the pain threshold at T3,the whole brain was removed for determination of the c-fos expression in neurons in the midbrain periaqueductal gray by immunohistochemistry.Results Compared with group C,the MWT was significantly decreased,cumulative pain scores were increased,and the expression of c-fos in neurons in the midbrain periaqueductal gray was upregulated at T1-3 in I and D groups (P＜0.05).Compared with group I,the MWT was significantly increased,the cumulative pain score was decreased,and the expression of c-fos protein in neurons in the midbrain periaqueductal gray was down-regulated at T1.3 in group D (P＜0.05).Conclusion Dezocine mitigates incisional pain through inhibiting the expression of c-fos in neurons in the midbrain periaqueductal gray of rats.