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Table of Content
18 April 2021, Volume 53 Issue 2
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  • Therapeutic effect of gene silencing peptidyl arginine deaminase 4 on pulmonary interstitial lesions induced by collagen-induced arthritis mice
    ZHAO Kai,CHANG Zhi-fang,WANG Zhi-hua,PANG Chun-yan,WANG Yong-fu
    2021, (2):  235-239.  doi: 10.19723/j.issn.1671-167X.2021.02.001    
    Abstract ( 798 )   HTML ( 37 )   PDF (3076KB) ( 199 )   Save
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    Objective: To investigate the therapeutic effect of gene silencing peptidyl arginine deaminase 4 (PAD4) on pulmonary interstitial lesions induced by collagen-induced arthritis (CIA) mice, and possible mechanisms. Methods: A CIA mouse model was established in DBA/1 mice, followed by a tail vein injection of the virus solution prepared by the PAD4-siRNA expression vector once a week for 8 times. The mice were sacrificed at the end of the experiment. The expression of PAD4 mRNA in lungs was detected by real-time quantitative PCR (qRT-PCR). The expression of PAD4 protein was detected by tissue immunohistochemistry. Cell culture was performed by spleen tissue. Flow cytometry changes in the ratio of Tfh cells to Tfr cells were examined; lung staining was performed in the lungs to observe changes in lung pathology. Results: (1) Compared with the blank group, the expression of PAD4 mRNA in the lung tissue of the model group increased, the difference was statistically significant (P< 0.05). PAD4 mRNA in the lung tissue of the CIA mice after PAD4-siRNA treatment. The expression level was significantly lower than that of the model group and the negative control group, and the difference was statistically significant (P<0.05). (2) Red fluorescence was less in the lung tissue of the blank group, while more red fluorescence was observed in the inflammatory cell infiltration area and trachea around the lung tissue of the model group and the negative control group, and the red fluorescence of the three groups after PAD4-siRNA treatment was significantly reduced; (3) Compared with the blank group, the proportion of Tfh cells in the model group increased, the difference was statistically significant (P < 0.05), the proportion of Tfh cells in spleen cells of the CIA mice after PAD4-siRNA treatment was significantly lower than that of the model group and the negative control group, the difference was statistically significant (P < 0.05); compared with the blank group, in the mouse spleen cells in the model group the proportion of Tfr cells was slightly decreased, but the difference was not statistically signifi-cant. The proportion of Tfr cells in the spleen cells of the mice increased after PAD4-siRNA treatment, but the difference was statistically significant only in the PAD4-siRNA2 group compared with the model group and the negative control group (P<0.05); (4) The proportion of Tfh/Tfr in the spleen cells of the model group was increased, compared with the blank group, the difference was statistically significant (P<0.05); the ratio of Tfh/Tfr in the three groups after PAD4-siRNA treatment all decreased, the difference was statistically significant (P<0.05); (5) Compared with the blank group, the alveolar wall of the lung tissue of the model group was thickened, the inflammatory cell infiltration was increased, and the lung tissue destruction and inflammatory infiltration of the CIA mice were decreased after PAD4-siRNA treatment. The degree of reduction was reduced. Conclusion: Gene silencing of PAD4 can reduce the proportion of Tfh cells, increase the proportion of Tfr cells, reverse the proportion of Tfh/Tfr, and reduce the degree of interstitial lesions and inflammatory infiltration of lung tissue.

    Effects of ultrafine particulates on cardiac function in rat isolated heart
    BAI Feng,HE Yi-fan,NIU Ya-nan,YANG Ruo-juan,CAO Jing
    2021, (2):  240-245.  doi: 10.19723/j.issn.1671-167X.2021.02.002    
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    Objective: To evaluate whether ultrafine particulates (UFPs) have direct deleterious effects on cardiac function through activating MAPK signaling. Methods: Langendorff-perfused Sprague-Dawley rat hearts were randomly divided into 2 groups (n=10/each group). In control group, the rat hearts were perfused with Tyrode’s buffer for 40 min; in UFPs-treated group, the hearts were perfused with UFPs at a concentration of 12.5 mg/L. Cardiac function was determined by measuring left ventricular developed pressure (LVDP), left ventricular peak rate of contraction and relaxation (±dp/dtmax) and coronary flow (CF). The levels of malondialdehyde (MDA), superoxide dismutase (SOD), total anti-oxidant capacity (TAOC) were detected in order to evaluate cardiac oxidative stress via the thiobarbituric acid assay, water soluble tetrazolium salt assay and colorimetry, respectively. The expressions of p-p38 MAPK, p-ERKs and p-JNKs in the myocardium were observed using immunohistochemical staining and Western blots. Results: No significant changes in cardiac function were detected before and after the perfusion in control group while UFPs perfused hearts showed a decline in cardiac function in a time-dependent manner (all P<0.05). In UFPs-treated group, LVDP, +dp/dtmax, -dp/dtmax and CF were statistically reduced from (82.6±2.1) mmHg, (1 624±113) mmHg/s, (1 565±116) mmHg/s, (12.0±0.2) mL/min to (56.8±4.4) mmHg, (1 066±177) mmHg/s, (1 082±134) mmHg/s, (8.7±0.3) mL/min (all P<0.05), respectively. Furthermore, The comparison between the two groups observed that UFPs perfusion caused a significant decrease in cardiac function at 30 and 40 min compared with the control group (all P<0.05). At the end of the perfusion, the level of MDA was increased from (0.98±0.14) nmol/L to (1.95±0.18) nmol/L, while SOD and TAOC were reduced from (12.50±1.87) U/mL and (6.83±1.16) U/mL to (6.50 ±1.04) U/mL and (3.67±0.82) U/mL (all P<0.001) in UFPs group, respectively. In coincidence with these changes, immunohistochemistry and Western blots results showed that the levels of p-p38 MAPK, p-ERKs and p-JNKs in the myocardium significantly increased in UFPs group as compared with control group (all P<0.05). Conclusion: The results of this study demonstrated that the short-term exposure of UFPs to the isolated rat hearts has direct and acute toxic effects on cardiac function, probably related to attenuation of anti-oxidative capacity and activation of MAPK signaling pathways.

    Semiquantitative parameters of 18F-FDG PET/CT, gene mutation states of epidermal growth factor receptor and anaplastic lymphoma kinase in prognosis evaluation of patients with lung adenocarcinoma
    LIAO Xu-he,WANG Rong-fu,LIU Meng,CHEN Xue-qi,XIONG Yan,NONG Lin,YIN Lei,ZHANG Bing-ye,DU Yu-jing
    2021, (2):  246-254.  doi: 10.19723/j.issn.1671-167X.2021.02.003    
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    Objective: To explore the valuable predictors for evaluating progression-free survival (PFS) in patients with lung adenocarcinoma, we analyzed the potential roles of standardized uptake value (SUV)-derived parameters from 18F-FDG PET/CT, combining with the gene mutation states of epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK), and other clinical characteristics. Methods: Data of 84 lung adenocarcinoma patients pre-treated, who underwent 18F-FDG PET/CT scans, EGFR gene mutations test, ALK rearrangement assay and other relative tests, were retrospectively collected. Then a series of clinical parameters including EGFR/ALK mutation status and SUV-derived features [maximum standardized uptake value (SUVmax), average of standardized uptake value (SUVmean), metabolic tumor volume (MTV), and total lesion glycolysis (TLG)] were evaluated. Best possible cutoff points for all measuring parameters were calculated using receiver operating characteristic curve (ROC) analysis. Survival analysis was performed using Cox proportional hazards model to determine the prognostic markers for progression-free survival (PFS). Survival curves were obtained through Log-rank test and Kaplan-Meier curve. Results: The median follow-up period was 31 months (24 to 58 months). It was found that SUVmax (≥3.01), SUVmean (≥2.25), MTV (≥25.41 cm 3), and TLG (≥55.02) of the primary tumors were significantly associated with PFS in univariate Cox proportional hazards regression. Then regardless of age, gender, co-morbidity, EGFR/ALK mutation status, and treatment program, TLG (≥ 55.02, HR=4.965, 95%CI: 1.360-18.133), TNM stage (Ⅲ/Ⅳ, HR=7.811, 95%CI: 2.977-20.489), pro-gastrin releasing peptide (proGRP) (≥45.65 ng/L, HR=4.070, 95%CI: 1.442-11.487), tissue polypeptide antigen (TPA) (≥68.20 U/L, HR=6.996, 95%CI: 1.458-33.574), alkaline phosphatase (ALP) (≥82.50 IU/L, HR=4.160, 95%CI: 1.416-12.219) and ratio of activated partial thromboplastin time (aPTTR) (≥1.16: HR=4.58, 95%CI: 1.913-10.946) showed the independently relevant to PFS through multivariate Cox proportional hazards analysis. The EGFR mutant (P=0.343) and ALK rearrangement (P=0.608) were not significant either in survival analysis. Conclusion: High SUV-derived parameters (SUVmax, SUVmean, MTV and TLG) might provide prognostic value to some extent. Especially, TLG, and other clinical features [TNM stage, proGRP, TPA, ALP, and aPTTR] could be independently and significantly associated with PFS of lung adenocarcinoma patients. However, EGFR/ALK gene status could not be effectively relevant to PFS in lung adenocarcinoma patients.

    Expression of plasma Dickkopf-1 in patients with rheumatoid arthritis and its correlation with peripheral blood T cell subsets
    CAO Di,WANG Yan,WANG Liu-qing,SUN Xiao-lin,HUANG Fei,MENG Yang,REN Li-li,ZHANG Xue-wu
    2021, (2):  255-260.  doi: 10.19723/j.issn.1671-167X.2021.02.004    
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    Objective: To detect the levels of Dickkopf-1 (DKK-1) in the plasma of patients with rheumatoid arthritis (RA), and to analyze their correlation with peripheral blood T cell subsets and clinical indicators. Methods: Enzyme-linked immunosorbent assay (ELISA) was used to detect plasma DKK-1 levels in 32 RA patients and 20 healthy controls, and to record the various clinical manifestations and laboratory indicators of the RA patients, and flow cytometry to detect peripheral blood T cell subsets in the RA patients (Including Treg, nTreg, aTreg, sTreg, Teff, Tfh, CD4+CD161+T, CD8+T, CD8+CD161+T cells). The plasma DKK-1 levels between the two groups were ompared, and its correlation with peripheral blood T cell subsets and clinical indicators analyzed. Results: (1) The plasma DKK-1 concentration of the RA patients was (124.97±64.98) ng/L. The plasma DKK-1 concentration of the healthy control group was (84.95±13.74) ng/L. The plasma DKK-1 level of the RA patients was significantly higher than that of the healthy control group (P<0.05), and the percentage of CD8+CD161+T cells in the peripheral blood of the RA patients was significantly higher than that of the healthy control group (P<0.05). (2) The plasma DKK-1 level was positively correlated with erythrocyte sedimentation rate (r=0.406, P=0.021),DAS28 score (r=0.372, P=0.036), immunoglobulin G(r=0.362, P=0.042), immunoglobulin A(r=0.377, P=0.033) ; it had no correlation with age, course of disease, C-reactive protein, rheumatoid factor, anti-cyclic citrullinated peptide antibody, immunoglobulin M, complement C3, complement C4, white blood cell, neutrophil ratio. (3) The plasma DKK-1 level in the RA patients was positively correlated with the percentage of peripheral blood CD161+CD8+T cells (r=0.413, P=0.019);it had no correlation with Treg, nTreg, aTreg, sTreg, Teff, Tfh, CD4+CD161+T, CD8+T cells. (4) The percentage of CD161+CD8+T cells was negatively correlated with erythrocyte sedimentation rate (r=-0.415, P=0.004), C-reactive protein (r=-0.393, P=0.007), DAS28 score(r=-0.392, P=0.007),rheumatoid factor (r=-0.535, P<0.001), anti-citrullinated protein antibody (r=-0.589, P<0.001), immunoglobulin G(r=-0.368, P=0.012) immunoglobulin M (r=-0.311, P=0.035); it had no correlation with age, disease course, immunoglobulin A, complement C3, complement C4,white blood cell,and neutrophil ratio. Conclusion: RA patients’ plasma DKK-1 levels and the percentage of CD8+CD161+T cells in T cell subsets in peripheral blood increase, which may be related to the secretion of proinflammatory cytokines in patients; DKK-1 is involved in the regulation of bone homeostasis and can be used as a marker of bone destruction in RA.

    Analysis of risk factors influencing the detection rate of urate crystal by dual energy computed tomography
    XIE Yi-fan,WANG Yu,DENG Xue-rong,GENG Yan,JI Lan-lan,ZHANG Zhuo-li
    2021, (2):  261-265.  doi: 10.19723/j.issn.1671-167X.2021.02.005    
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    Objective: To explore the risk factors of detection of uric acid crystals by dual energy CT (DECT) in patients with gout diagnosed by gold standard. Methods: From June 2011 to December 2018, clinical data of 29 patients were collected who were diagnosed with acute or chronic gout by positive polarized light analysis of joint synovial fluid in First Hospital of Peking University. Chi-square test, Logistic regression and t-test were used. The relationship between DECT and the clinical data, laboratory examination and drug treatment were analyzed. Results: In this study, 29 patients were included, of whom, 22 patients were detected with uric acid crystals by DECT, and 7 patients were not. According to whether the uric acid crystals were detected or not by DECT, the patients were divided into two groups. Compared with the negative group,the patients were older in positive group [(47±12) vs. (39±11) years, P=0.15], had higher body bass index (BMI) [(27.9±3.7) vs. (22.8±2.1) kg/m2, P=0.002], longer gout disease duration [(135±102) vs.(45±53) months, P=0.035], higher in the highest serum uric acid in history [(643±121) vs. (543±103) μmol/L, P=0.043]. Although uric acid near DECT in positive group was higher than in negative group, there was no statistical difference [(558±150) vs. (513±89) μmol/L, P=0.497]. Comparing positive group with negative group, the percentage of the patients in acute phase was higher than in chronic phase [18(81.8%) vs. 4(57%), P=0.311];the percentage of the patients taking uric-acid-lowering drugs was higher than the other group [22(100%) vs. 5 (71%), P=0.052];the percentage of the patients with recurrent typical attacks was higher than that of those without typical attacks [22 (100%) vs.6 (85%), P=0.241]. The consistency of symptoms and the finding of uric acid crystals by DECT had been compared between the joints. The right knee joint had the highest consistency (Kappa=0.627), followed by the left MTP1 (Kappa=0.58), the right metatarsophalangeal 1(MTP1, Kappa=0.551) and the left knee (Kappa=0.494), all of which had statistical significance. The consistency of the ankle joint was lower (the right ankle joint: Kappa=0.19, the left ankle joint: Kappa=0.256), showing no statistical significance. BMI (kg/m2) [2.307 (1.139-4.670), P=0.02], gout duration (years) [0.306 (0.906-4.881), P=0.186], and the highest uric acid level in history (mg/dL) [0.023 (0.981-2.764), P=0.137] had relationship to the positive result of urate crystals in DECT. Conclusion: Gout patients with larger BMI, higher previous highest uric acid value and longer gout duration had higher sensitivity of the positive result in DECT.

    Clinical characteristics and related factors of systemic lupus erythematosus with interstitial pneumonia
    XIA Fang-fang,LU Fu-ai,LV Hui-min,YANG Guo-an,LIU Yuan
    2021, (2):  266-272.  doi: 10.19723/j.issn.1671-167X.2021.02.006    
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    Objective: To investigate the clinical features, radiologic scores and clinically relevant risk factors prognosis of secondary interstitial lung disease (ILD) in patients with systemic lupus erythematosus (SLE). Methods: In this study, 60 SLE patients in Department of Rheumatology of the First Affiliated Hospital of Baotou Medical College and Taizhou First People’s Hospital from January 2015 to March 2019 were retrospectively analyzed. All of those 60 patients with SLE underwent lung high resolution computed tomography (HRCT) examination. We used a 1 ∶1 case-control study. There was a matching of age and gender between the two groups. Thirty patients with SLE related ILD (SLE-ILD) were in the case group, and 30 patients with SLE without ILE (SLE non-ILD) were in the control group. The clinical features, pulmonary function test, radiologic characteristic of SLE patients were collected and were used to analyze SLE-ILD. Results: In this study, we reached the following conclusions: First, there were statistically significant differences in chest tightness/shortness of breath, Raynaud’s phenomenon, and Velcro rale between SLE-ILD and SLE non-ILD patients (both P<0.05); Second, hemoglobin (Hb) and albumin (ALB) in the patients of SLE-ILD had a significant decrease compared with the patients of SLE non-ILD. Blood urea nitrogen (BUN), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) increased in SLE-ILD patients compared with SLE non-ILD patients, the difference had statistical significance (P<0.05); Third, for SLE-ILD patients, the most common type was non-specific interstitial pneumonia (NSIP), followed by usual interstitial pneumonia and lymphocytic interstitial pneumonia; Fourth, there was no significant difference in clinical-radiology-physiology scores between the different ILD types (P>0.05), similarly, the lung HRCT score and lung function between different ILD types had no significant difference (P>0.05); Fifth, multivariate Logistic regression analysis showed that decreased albumin and chest tightness/shortness of breath might be the risk factor for SLE-ILD. Conclusion: There are statistically significant differences between the SLE-ILD group and SLE non-ILD group in terms of chest tightness/shortness of breath, Velcro rale and Raynaud’s phenomenon. Decreased albumin and chest tightness/shortness of breath in SLE patients should be alerted to the occurrence of ILD. NSIP is the most common manifestation of SLE-ILD.

    Analysis of the mass skiers’ injury in a large ski resort in Chongli, China
    YANG Yu-ping,MA Xiao,CHEN Na-yun,JIANG Yan-fang,ZHANG Xiao-wei,DING Zhong-wei,AO Ying-fang
    2021, (2):  273-278.  doi: 10.19723/j.issn.1671-167X.2021.02.007    
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    Objective: To make a retrospective analysis of the injuries of skiing population in a large ski resort in Chongli, China and provide a basis for predicting the rapidly increasing medical needs for ski injuries in the context of the 2022 Winter Olympic Games. Methods: The basic data of all injured skiers who were treated in a medical station of a large ski resort in Chongli during the snow season from November 2017 to March 2018 and from November 2018 to March 2019 were collected. The number of skiers, the number of injuries, the causes of injuries, the types of injuries and the locations of injuries were compared. Results: A total of 753 skiers were injured in two snow seasons, and the estimated average incidence of injury was 4.53 and 4.46 per 1 000 skier days at the resort respectively. The average daily injury rate per 1 000 skiers in November of the two snow seasons was relatively low, with 2.20 and 1.38 cases respectively. The difference of injury rate in different months might have little to do with snowfall and more to do with passenger flow. In both the snow seasons, men accounted for more injuries than women, and injured skiers aged between 21 and 30 accounted for the largest proportion, reaching 36.8%. The main causes of injuries were falls (76.6%). The highest rate of injury was in the head and neck (17.9%), followed by the knee (17.4%) and wrist and fingers (13.3%). The most common types of injuries were contusion and trauma (29.5%) and joint and/or ligament injuries (22.2%). Children (2-12 years old) accounted for 12.7% of all the injured skiers. The rate of moderate to severe injuries (including fractures, concussions, etc.) was 34.8% among the injured patients over 50 years of age. Conclusion: The snow resort should focus on injuries to children and elderly skiers and carry out targeted guidance and rescue work. In order to better ensure the medical safety of skiers, the ski resort medical station and nearby treatment hospitals should be equipped with a corresponding number of medical personnel and equipment, and the ski resort should further improve its safety management and rescue system.

    Characteristics and related factors of plantar pressure in the chronic ankle instability individuals
    HOU Zong-chen,AO Ying-fang,HU Yue-lin,JIAO Chen,GUO Qin-wei,HUANG Hong-shi,REN Shuang,ZHANG Si,XIE Xing,CHEN Lin-xin,ZHAO Feng,PI Yan-bin,LI Nan,JIANG Dong
    2021, (2):  279-285.  doi: 10.19723/j.issn.1671-167X.2021.02.008    
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    Objective: To analyze characteristics and related factors of the plantar pressure during the level walking and single leg standing in the chronic ankle instability (CAI) individuals. Methods: From April 2019, 75 CAI individuals and 40 healthy individuals were enrolled in this study. Both of the static and dynamic plantar pressure were measured during six times level walking and three times single leg standing testing. The data including peak force, time to peak force in various foot contact areas and the time to boundary (TTB) and velocity of center of pressure (COP) were measured and compared between the affected side and the unaffected side and between the CAI cases and the healthy individuals. The correlations between the plantar pressure and the gender, Beighton score, affected side and body mass index (BMI) were analyzed. Results: The characteristics of plantar pressure distribution in the CAI individuals included: (1) During the level walking, the affected side showed the similar pressure contribution as the unaffected side (P>0.05). While compared with healthy individuals, there was a significantly higher peak force in the 5th metatarsal area (t=-3.86, P=0.03) of the affected side, lower peak force in the 1st (t=2.99, P=0.02), 2nd metatarsal head areas (t=2.09, P=0.01) of the affected side, medial hindfoot areas of both sides (affected, t=2.33, P=0.01; unaffected, t=3.74, P=0.02) and toes areass of both sides (affected, t=2.23, P=0.01; unaffected, t=3.28, P=0.02) and a delay to peak force in the 4th metatarsal head area (t=3.33, P=0.01) of the affected side. (2) During the single leg standing, the CAI individuals showed significantly worse balance control in the anterior/posterior direction (P<0.05) and lateral/medial direction (P<0.05) compared with the healthy controls, and the affected side had more severe balance control deficit in the lateral/medial direction (P<0.05). (3) The women (P<0.05) and the individuals with higher Beighton scores (P<0.05) showed worse balance control deficit in the lateral/medial direction. Conclusion: CAI individuals showed significantly a more lateral shifted plantar distribution during the level walking compared with the healthy individuals and the tendency was worse on the affected sides, and showed worse balance control in the anterior/posterior direction and lateral/medial direction during the single leg standing. The women and those with generalized ligament laxity showed significantly worse balance control.

    Risk factors for multiple debridements of the patients with deep incisional surgical site infection after spinal surgery
    ZHOU Bo-lin,LI Wei-shi,SUN Chui-guo,QI Qiang,CHEN Zhong-qiang,ZENG Yan
    2021, (2):  286-292.  doi: 10.19723/j.issn.1671-167X.2021.02.009    
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    Objective: To investigate the risk factors that contribute to multiple debridements in patients suffering from deep incisional surgical site infection after spinal surgery and advise medical personnel to pay special attention to these risk factors. Methods: We retrospectively enrolled 84 patients who got deep incisional surgical site infection after spinal surgery from Jan. 2012 to Dec. 2017. The infections occurred within 30 days after the surgery, and the identification met the criteria of deep incisional surgical site infection of Centers of Disease Control (CDC). Early debridement with first stage closure of the wound and a continuous inflow-outflow irrigation system was used, and reasonable antibiotics were chosen according to the bacterial culture results. During the treatment, the vital signs, clinical manifestations, blood test results, drainage fluid colour and bacterial culture results were acquired. If the infection failed to be controlled or relapsed, a second debridement was performed. Of the 84 cases, 60 undergwent single debridement which included 36 male cases and 24 female cases, and the age ranged from 36 to 77 years, with a mean of 57.2 years. Twenty four had multiple debridements (twice in 14 cases, three times in 6 cases, four times in 1 case, five times in 2 cases, six times in 1 cases) which included 17 male cases and 7 female cases, and the age ranged from 21 to 70 years, with a mean of 49.5 years. Risk factors that predispose patients to multiple debridements were identified using univariate analysis. Risk factors with P values less than 0.05 in univariate analysis were included together in a multivariate Logistic regression model using back-forward method. Results: Multiple debridements were performed in 28.6% of all cases. The hospital stay of multiple debridements group was (82.4±46.3) days compared with (40.4±31.5) days in single debridement group (P=0.018). Instrumentation was removed in 6 cases in multiple debridements group and 4 cases in single debridement group (P=0.049). Flap transplantation was performed in 7 cased in multiple debridements group while none in single debridement group (P<0.001). Diabetes, primary operation duration longer than 3 hours, primary operation blood loss more than 400 mL, bacteriology examination results, distant site infection were significantly different between the two groups in univariate analysis. In multivariate analysis, primary operation duration longer than 3 hours (OR=3.60, 95%CI: 1.12-11.62), diabetes (OR=3.74, 95%CI: 1.06-13.22), methicillin-resistant Staphylococcus aureus (MRSA) infected (OR=16.87, 95%CI: 2.59-109.73) were the most important risk factors related to multiple debridements in the patients with deep incisional surgical site infection after spinal surgery. Conclusion: Diabetes, primary operation duration more than 3 hours, MRSA infected are independent risk factors for multiple debridements in patients suffering from deep incisional surgical site infection after spinal surgery. Special caution and prophylaxis interventions are suggested for these factors.

    Multivariate analysis of varus after Oxford unicompartmental knee arthroplasty
    JI Song-jie,HUANG Ye,WANG Xing-shan,LIU Jian,DOU Yong,JIANG Xu,ZHOU Yi-xin
    2021, (2):  293-297.  doi: 10.19723/j.issn.1671-167X.2021.02.010    
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    Objective: To analyze the preoperative influencing factors of varus after Oxford unicompartmental knee arthroplasty. Methods: A total of 660 patients (767 knees) undergoing Oxford unicompartmental knee arthroplasty in adult joint reconstruction surgery department of Beijing Jishuitan Hospital from January 2018 to December 2019 were retrospectively analyzed. Inclusive criteria: diagnosis was osteoarthritis, single compartment lesions in the medial side of the knee; preoperative flexion deformity was less than 10°, active range of motion was greater than 90°; preoperative X-ray full-length images of both lower limbs showed less than 15° varus (Noyes method); anterior cruciate ligament was well functioned, The cartilage of lateral compartment of knee joint was intact. Exclusion criteria: combined with other inflammatory arthropathy; combined with extraarticular deformity; previous knee surgery history. The average age of the patients was (64.4±8.1) years, including 153 males and 497 females. The degree of post-operative varus was measured with Noyes method. The total patients were divided into varus group (Noyes≥3 °) and normal group (Noyes<3 °). Gender, age, body mass index (BMI), range of motion (ROM), preoperative flexion deformity (FD), American Knee Society pain score (AKS) and American Knee Society function score (AKS function) were recorded. The standard anteroposterior and lateral X-ray films of knee joint and full-length lower extremity kinematic line films were taken by Sonialvision Safine Ⅱ (Shimadzu, Japan) multi-function digital tomography system. The image was measured by picture archiving and communication system (PACS). The following angles were measured preoperative Noyes angle, lateral distal femoral angle (LDFA), medial proximal tibial angle (MPTA) and joint line converge angle (JLCA) were measured and analyzed. Results: Gender(P=0.346), operative side (P=0.619), age (P=0.746), BMI (P=0.142), preoperative ROM (P=0.102), preoperative knee pain score (P=0.131) and functional score (P=0.098) were not risk factors for postoperative varus. The influencing factors of postoperative varus were preoperative MPTA<84 ° (P= 0.018, OR= 3.712, 95%CI: 1.250-11.027), preoperative Noyes > 5°(P=0.000, OR= 3.105, 95%CI: 1.835-5.254), preoperative FD > 5° (P= 0.001, OR=1.976, 95%CI: 1.326-3.234). Pre-operative LDFA (P=0.146) and preoperative JLCA (P= 0.709) had no significant effect on postoperative kinematic line. Conclusion: Patients with severe preoperative varus, especially those with varus deformity mainly from the tibial side, and those with preoperative flexion deformity are more prone to get varus lower extremity kinematic line after Oxford unicompartmental knee arthroplasty.

    Analysis of bleeding risk in percutaneous renal biopsy in Tibet
    ZHANG Lei,LI Guo-liang,DANG Zong-hui, ,A yong,WU Ling-jie,LIU Li-jun
    2021, (2):  298-301.  doi: 10.19723/j.issn.1671-167X.2021.02.011    
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    Objective: To observe the postoperative bleeding after percutaneous renal biopsy (PRB) in Tibet, To analyze and summarize the risk factors associated with bleeding in high altitude patients to improve the safety of surgery. Methods: A retrospective analysis of 150 cases of PRB in the Department of Nephrology, People’s Hospital of Tibet Autonomous Region from May 2016 to May 2018 were carried out, and the correlations between the potential risk factors (gender, age, blood pressure, hemoglobin, platelet, serum creatinine) and postoperative bleeding events were analyzed. Results: During the study period, the 150 patients receiving procedure of PRB were enrolled in our hospital, with an average age of (41.2±15.6) years, of whom 58.7% (88/150) were male, 41.3% (62/150) were female, and major bleeding complications occurred in 12 biopsies (8.0%, 12/150). Six cases for men and women, respectively. The mean age in the bleeding group seemed to be higher than that in the non-bleeding group [(48.3±20.0) years vs. (40.6±15.1) years, P=0.099]. There was no significant difference in the incidence of hypertension, hemoglobinemia, urea nitrogen and prothrombin time between the two groups. The level of serum creatinine in the hemorrhage group seemed to be higher than that in the non-bleeding group (P=0.090), and the time of the hemorrhagic group was longer than that in the non-bleeding group (P=0.069). The platelet count in the bleeding group was significantly lower than that in the non-bleeding group (P<0.05). Multivariate Logistic regression analysis showed that the prolonged activation of partial prothrombin time and lower platelet count had a relatively high risk of bleeding, which was statistically significant (P=0.079, P=0.082). Conclusion: PRB is safe and reliable on the whole in plateau areas; Old age, low platelet count, decreased renal function and prolonged activated partial coagulation time are related to postoperative bleeding of PRB, and hyperhemoglobin is not a risk factor for bleeding. High hemoglobin is not a risk factor for postoperative bleeding of PRB at high altitude.

    Clinical value of inflammatory biomarkers in predicting prognosis of patients with ureteral urothelial carcinoma
    CHEN Huai-an,LIU Shuo,LI Xiu-jun,WANG Zhe,ZHANG Chao,LI Feng-qi,MIAO Wen-long
    2021, (2):  302-307.  doi: 10.19723/j.issn.1671-167X.2021.02.012    
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    Objective: To evaluate the clinical value of inflammation-related markers in predicting the prognosis of patients with ureteral urothelial carcinoma. Methods: 200 patients with ureteral urothelial carcinoma were randomly divided into two groups by split sample validation: modeling group and validation group. Paraffin embedded pathological specimens of the patients were reviewed. Immunohistochemical method was used to detect tumor-infiltrating neutrophil (TIN) (CD66b+), tumor-associated macrophage (TAM) (CD163+), lymphocyte (CD+, CD4+, CD8+) counts, peripheral blood neutrophil / lymphocyte ratio (NLR) and tumor tissue neutrophil/monocyte ratio (NMR). According to the results of pathological staging, the patients were divided into non-muscle-invasive and muscle-invasive ureteral urothelial carcinoma group. The resolution of the models was evaluated, and the prognostic nomogram models including only peripheral blood parameters and all parameters were established to compare the accuracy of the two models in predicting the prognosis of patients with urothelial carcinoma of the ureter. Results: The median follow-up time was 36 months, the progression-free survival was 40 months, and 42 cases (21.0%) showed tumor progression within 3 years. Tumor size, pathological stage and pathological grade were all single-factor variables predicting the first recurrence of ureteral urothelial carcinoma three years after operation. Tumor size, pathological stage, pathological grade, TIN, TAM, NLR and NMR were multi-factor variables predicting the first recurrence three years after operation. Among 104 cases of non-muscle-invasive ureteral urothelial carcinoma, 10 cases (9.6%) recurred for the first time 3 years after operation, 96 cases (33.3%) of muscle invasive ureteral urothelial carcinoma, and the diffe-rence between the two groups was statistically significant (χ2=15.53, P<0.05). The predictive nomogram model of progression free survival was established. The concordance index of progression free survi-val was 0.722 (95%CI: 0.70-0.78) in non-muscle-invasion group, and 0.725 (95%CI: 0.71-0.79) in muscle-invasion group, which was in good agreement with the observed 3-year survival rate. The results of discrimination test showed that the concordance index of the whole parameter prediction model of ureteral urothelial carcinoma was 0.726, which was higher than that of peripheral blood parameters (consistency index 0.672). The immune microenvironment of ureteral urothelial carcinoma improved the prediction accuracy of the model. Conclusion: The prognosis prediction model based on immune inflammation-related markers was established as a perfection and supplement for the existing pathological grading and staging system, providing a basis for accurate individualized treatment of patients with urete-ral urothelial carcinoma. The prognosis prediction model based on the relevant indicators of peripheral blood samples is established, which is easy to obtain specimens, and the detection method is simple and economical, which is more conducive to clinical application.

    Mediating effect of milk intake between family socioeconomic status and body mass index of children and adolescents
    SHI Xin-ran,AN Mei-jing,CHEN Tian-jiao,Ma jun
    2021, (2):  308-313.  doi: 10.19723/j.issn.1671-167X.2021.02.013    
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    Objective: To examine the association between family socioeconomic status (SES) and body mass index (BMI) z-score of children and adolescents, and the mediating effect of milk intake in this association. Methods: In the study, 2 496 students and their parents were selected from 16 schools (4 urban middle schools, 4 rural middle schools, 4 urban primary schools, and 4 rural primary schools) using a stratified cluster sampling method. The frequency and amount of weekly milk intake from the 7-day Food Records reported by the students were extracted. The parents’ education and household income were the indicators of family SES. The mediating effect of milk intake between family SES and BMI z-score of children and adolescents were tested using the PROCESS add-on SPSS software. Results: Parents’ education level and household income were positively correlated with BMI z-score of children and adolescents (P=0.001 and 0.038, respectively). The overall average daily intake of milk was (0.92±0.84) servings, and the frequency was (4.43±2.70) days per week. The students of primary school, in urban areas, with higher parents’ education level, with higher household income, and being non-obese were likely to have higher frequency and amount of milk intake. Milk intake was one of the mediating factors in the relationship between family SES and BMI z-score of children and adolescents. Specifically, the mediating effect of the frequency of milk intake accounted for -6.57% and -10.21% of the total effects of the association between the parents’ education and the household income with BMI z-score of children and adolescents, respectively. The mediating effect of the daily intake of milk accounted for -3.63% and -5.86% of the total effects of the association between the parents’ education and the household income with BMI z-score of children and adolescents, respectively. Conclusion: The milk intake of Chinese children and adolescents still needs to be improved. High family SES was found to contribute to high BMI z-score, mediated by the milk intake which was the protective factors of BMI z-score. Further research is needed to study other dietary or physical exercise behaviors that mediate the relationship between family SES and BMI z-score of children and adolescents in order to adopt more targeted interventions.

    Association between community socioeconomic status and adults’ self-rated health in China
    WANG Zhi-cheng,GUO Yan
    2021, (2):  314-319.  doi: 10.19723/j.issn.1671-167X.2021.02.014    
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    Objective: To examine whether community socioeconomic status is associated with self-rated health independent of individual socioeconomic status for urban and rural residents, and to provide policy implications for improving the health status of the socioeconomically underdeveloped communities in China. Methods: Based on the baseline data of China Family Panel Studies (CFPS) in 2010, principal component analysis was used to construct community socioeconomic index (SEI) based on average years of schooling, average income and average wealth at the community level. Community SEI was defined as the standardized first principal component score. In combination with the adult data from CFPS 2012 follow-up data, the multilevel Logistic regression model was used to analyze whether the community socioeconomic status had an independent contextual effect on the self-rated health of urban residents and rural residents after controlling individual-level socioeconomic status. Results: In the final analysis, 31 321 adult residents in 577 communities were included, of whom 8 423 were urban residents and 22 898 were rural residents. Community SEI ranged from -2.41 to 3.16, with a mean of 0 and a stan-dard deviation of 1. As the community SEI increased, the incidence of deprivations in different dimensions decreased, indicating the community socioeconomic status increased. The multilevel Logistic model controlling for both individual sociodemographic factors and community socioeconomic status showed that as the community SEI increased, the probability of poor self-rated health decreased, which indicated community SEI had a contextual effect on poor self-rated health. The contextual effect of community SEI on poor self-rated health was statistically significant for the rural residents (OR=0.84, 95%CI: 0.76-0.94) but not statistically significant for the urban adults (OR=0.94, 95%CI: 0.83-1.06). Conclusion: After controlling for individual socioeconomic status, community socioeconomic status was associa-ted with poor self-rated health for rural residents independent of individual socioeconomic status. Therefore, in order to improve the health status of the rural population, it needs not only individual-based health interventions, but also community-based health interventions.

    Accuracy of Xpert®MTB/RIF for the detection of tuberculosis and rifampicin-resistance tuberculosis in China: A systematic review and meta-analysis
    FENG Jing-nan,GAO Le,SUN Yi-xin,YANG Ji-chun,DENG Si-wei,SUN Feng,ZHAN Si-yan
    2021, (2):  320-326.  doi: 10.19723/j.issn.1671-167X.2021.02.015    
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    Objective: To systematically review the diagnostic accuracy of Xpert® Mycobacterium tuberculosis/rifampicin (Xpert® MTB/RIF) for the detection of active tuberculosis (TB) and rifampicin-resistance TB in Chinese patients. Methods: Four Chinese databases (SinoMed, CNKI, WanFang database, and VIP) and three English databases (PubMed, Embase, and The Cochrane Library) were searched from January 1, 2000 to September 15, 2017, to identify diagnostic tests about the accuracy of Xpert® MTB/RIF in Chinese patients. Two investigators screened the articles and extracted the information independently, and then the quality of each included study was evaluated by Quality Assessment of Diagnostic Accuracy Studies (QUADAS)-2. Bivariate random-effects meta-analysis was conducted to pool the sensitivity and specificity. In addition, subgroup analyses were performed based on patient type (TB patient and TB suspected patient), sample type (sputum, bronchoalveolar lavage fluid and others). All statistical analyses were conducted with Stata version 13.0. Results: A total of 47 articles were included in this systematic review. Most of them (38 articles) were in Chinese and only 9 articles were in English. All the articles were published during 2014 to 2017, and the sample size ranged from 31 to 3 151. Forty articles including 42 comparisons about TB were finally included with the pooled sensitivity of 0.94 (95%CI: 0.92, 0.95) and the pooled specificity of 0.87 (95%CI: 0.84, 0.91). Subgroup analysis showed that different patient and specimen types had no significant differences on sensitivity, but the specificity of sputum group was higher than that of bronchoalveolar lavage fluid. As for the detection of rifampicin-resistant TB, 33 articles (38 comparisons) were analyzed, the pooled sensitivity and specificity were 0.92 (95%CI: 0.89, 0.94) and 0.98 (95%CI: 0.97, 0.99) respectively. There were no significant differences between the patient and specimen in the subgroup analyses. The Deeks funnel plot showed a possible publication bias for detecting active tuberculosis (P=0.08) and no publication bias for rifampicin-resistant TB (P=0.24). The likelihood ratio scatter gram showed that in clinical applications, Xpert® MTB/RIF had a good diagnostic ability for detecting active tuberculosis, and it had good clinical diagnostic value in detecting rifampicin-resistant TB. Conclusion: Xpert® MTB/RIF has good sensitivity and specificity in detecting TB and rifampicin-resistant TB in Chinese people. In particular, it has good clinical value in diagnosing rifampicin-resistance TB.

    One-stage surgery in patients with both cardiac and non-cardiac diseases
    YANG Yang,XIAO Feng,WANG Jin,SONG Bo,LI Xi-hui,ZHANG Shi-jie,HE Zhi-song,ZHANG Huan,YIN Ling
    2021, (2):  327-331.  doi: 10.19723/j.issn.1671-167X.2021.02.016    
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    Objective: To investigate the possibility and feasibility of one-stage cardiac and non-cardiac surgery. Methods: From July 1999 to August 2018, one hundred and eleven patients suffering from cardiac and non-cardiac diseases were treated by one-stage cardiac and non-cardiac operation in Department of Cardiac Surgery and Thoracic Surgery, General Surgery, Urinary Surgery, and Gynecology, Peking University First Hospital. There were 83 males (74.8%) and 28 females (25.2%), aged 41 to 84 years [mean age: (64.64±8.97) years]. The components of the cardiac disease included coronary heart disease, valvular heart disease, cardiac tumors, chronic constrictive pericarditis and congenital heart disease. The components of the non-cardiac diseases included lung benign and malignant diseases, thymoma and thymic cyst, breast cancer, chest wall giant hemangioma, digestive tract benign and malignant diseases, urinary system carcinoma and gynecological diseases. Results: Two patients died after operations in hospital; thus, the hospital mortality rate was 1.8%. One patient died of multiple organ failure on the 153th days after emergency coronary artery bypass grafting (CABG) combined with radical resection of bladder cancer. The other of pericardium stripping with lung cancer operation died of the multiple organ failure on the tenth day after surgery. The remaining 109 patients recovered and were discharged. There were 13 cases of complications during the days in hospital. The total operative morbidity was 11.7%: postoperative hemorrhage in 2 cases (1.8%), pulmonary infection and hypoxemia in 3 cases (2.7%), hemorrhage of upper digestive tract in 1 case (0.9%), incisional infection in 3 cases (2.7%), subphrenic abscess in 1 case (0.9%), and postoperative acute renal failure and hemofiltration in 3 case (2.7%). Of the 109 patients discharged, 108 patients were followed up. All the patients survived for 6 months, and 21 patients died due to tumor recurrence or metastasis within 1 to 5 years of follow-up, but no cardiogenic death. During the follow-up period, 1 patient developed cardiac dysfunction, 1 patient underwent percutaneous coronary intervention (PCI), 1 patient had cerebral hemorrhage due to excessive postoperative anticoagulation, and 1 patient suffered from incisional hernia. Conclusion: One-stage surgeries in patients suffering from both cardiac and non-cardiac benign or malignant diseases are safe and possible with satisfactory short-term and long-term survival.

    Radiofrequency obliteration of varicose veins of lower extremity guided by combined venography and ultrasonography
    YANG Guang-xin,LUAN Jing-yuan,JIA Zi-chang
    2021, (2):  332-336.  doi: 10.19723/j.issn.1671-167X.2021.02.017    
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    Objective: To explore the technical details and short-term effects of radiofrequency obliteration of varicose veins of lower extremities guided by combined venography and ultrasound. Methods: Thirty-seven patients with varicose veins of lower extremities were treated with radiofrequency obliteration using Olympus Celon RFiTT® under combined guidance of venography and ultrasound. The indications included varicose veins of lower extremities and reflux of the great saphenous vein confirmed by ultrasound. The contraindications included deep vein thrombosis, cardiac pacemaker, severe cardio- and cerebrovascular diseases or coagulation disorders. Under ultrasound guidance, the saphenous vein around knee level was punctured using a 21G needle, and a 7F sheath was introduced. Through the sheath a venography was made, and an Olympus Celon ProCurve radiofrequency catheter was inserted and advanced to the great saphenous vein under road map, and the catheter tip was positioned at the point 2 cm below the sapheno-femoral junction. The swelling anesthesia was made under ultrasound guidance. Then the radiofrequency obliteration was performed with pressing of the treatment section. The venography was repeated to ensure optimal outcomes. If necessary the radiofrequency obliteration could be repeated once to twice. After that the superficial varicose veins were stripping by small incisions under local anesthesia. After operation, medical decompression stocking was utilized immediately and sustained for three months. The clinical data, intraoperative radiation dose, exposure time and short-term effects were retrospectively analyzed. Results: After the operation, all the patients walked out of the operating room by themselves. The success rate of operation was 100%. The intraoperative radiation dose was 1.78-10.12 mGy (mean 6.56 mGy), and the exposure time was 61-448 s (mean 161 s). By 3 months follow-up, the symptoms were alleviated in all the 37 patients, and the occlusion rate was 100%. No complications such as skin burns, ecchymosis and deep venous thrombosis were found. Conclusion: The short-term effects of radiofrequency obliteration using Olympus Celon RFiTT® system in a manner of twice fixed point followed by once reciprocating radiofrequency were satisfactory. Radiofrequency obliteration of great saphenous veins guided by venography and ultrasound has not only the advantages of minimal trauma and rapid recovery, but also the advantages of accurate location, exact effect and avoidance of complications.

    Clinical outcomes of vocal fold immobility after tracheal intubation
    GENG Zhi-yu,GAO Wei-hua,WANG Dong-xin
    2021, (2):  337-340.  doi: 10.19723/j.issn.1671-167X.2021.02.018    
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    Objective: To assess the incidence of postoperative vocal cord immobility in patients following endotracheal intubation underwent general anesthesia. Methods: We retrospectively enrolled patients who underwent surgical procedures with endotracheal intubation under general anesthesia from January 2014 to December 2018 in Peking University First Hospital. Demographic and treatment data were obtained for patients with hoarseness and vocal cord fixation. The incidence of postoperative hoarseness and vocal cord fixation were presented and clinical outcomes were further analyzed. Results: A total of 85 998 patients following tracheal intubation and general anesthesia were enrolled in this study. Hoarseness was observed in 222 (0.26%) patients postoperatively. Sixteen patients (73%) were accomplished with symptoms of choking on water, dysphonia and sore throat. Twenty-nine patients with persistent hoarseness on the third postoperative day needed further treatment by otolaryngologists. Among them, seven patients had pharyngolaryngitis and twenty-two patients (0.026%) were demonstrated postoperative vocal cord immobility. There were seventeen patients (77%) with left-side vocal cord fixation and five patients (23%) with right-side vocal cord fixation. Nine patients were identified with arytenoid dislocation. Seven patients had left vocal cord fixation and two patients had right-side vocal cord fixation. Seven patients were intubated under the guidance of visual laryngoscope. One patient was confirmed difficult airway and intubated with light wand. One patient was inserted with laryngeal mask airway. One patient was suspected to have hoarseness caused by gastric tube before anesthesia. One patient showed simultaneously left recurrent laryngeal nerve abnormality on laryngeal electromyography result. The symptom of hoarseness ranged between 6 and 31 days. Three patients underwent closed reduction under local anesthesia and one patient demonstrated spontaneous recovery. Among the remaining thirteen patients with vocal cord immobility, two patients were demonstrated vocal cord paralysis. Eleven patients underwent neck surgery, thyroid surgery and cardiothoracic surgery and further examinations including laryn-geal electromyography and computed tomography help to determine the diagnosis were not performed. All patients were treated with inhaled corticosteroid conservatively. Five patients had significant improvement of symptom and almost regained normal voice. One patient had slight improvement and sixteen patients were not relieved before discharge. Conclusion: Patients with hoarseness and vocal fold immobility after endotracheal intubation should be treated properly and immediately.

    Investigation and validation of magnetic resonance white matter atlas for 0 to 2 years old infants
    HU Di,ZHANG Miao,KANG Hui-ying,PENG Yun
    2021, (2):  341-347.  doi: 10.19723/j.issn.1671-167X.2021.02.019    
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    Objective: To construct and verify a standard template of white matter based on Chinese normal 0 to 2 years old infants by using nonlinear high registration accuracy of non-rigid diffeomorphism paradigm (large deformation diffeomorphic metric mapping, LDDMM). Methods: Full-term spontaneous labor children without maternal pregnancy disease (hypertension, diabetes, etc.), intrauterine hypoxia and ischemia, head trauma, intracranial infection, intracranial surgery history, family history of mental disorders were selected. Diffusion tensor imaging (DTI) data from the 120 normal Chinese infants under 2 years old were acquired after excluding the existence of neurological diseases revealed by neurologists, radiologists and Gesell Developmental Scale. All the data were divided into six groups including group A:1 day to 1.5 months, group B: 1.5 to 4.5 months, group C: 4.5 to 9.0 months, group D: 9 to 15 months, group E: 15 to 21 months,and group F: 21 to 24 months. Data pre-processing,normalizing, tensor fitting and calculation of all the images were performed by using MRlcron,DtiStudio, DiffeoMap and SPM software package combined with LDDMM image registration method based on the selected single template of each group. And the average templates of each group were constructed by MATLAB software platform. The set of templates included fractional anisotropy figure (FA), color map, T1 weighted image, b0 image and the mean of all DWfs figures. Results: The templates of FA, T1, b0, DWfs and color map for the normal brain magnetic resonance white matter development of the Chinese infants aged 0 to 2 years were successfully established with the subjective scores exceeding 2 points. The objective evaluation root mean squared error was controlled below 0.19, and the cubic chart of brain alternation trend for the children aged 0 to 2 years was consistent with previous literature. Conclusion: Constructing a standard template of white matter based on Chinese normal infants, by using nonlinear high registration accuracy of non-rigid diffeomorphism paradigm provides not only a foundation of further research on brain development, mechanism and treatment of pediatric diseases associated with brain, but also objective and fair imaging information for medical education and research.

    Preparation and in vitro evaluation of fused deposition modeling 3D printed verapa-mil hydrochloride gastric floating formulations
    CHEN Di,XU Xiang-yu,WANG Ming-rui,LI Rui,ZANG Gen-ao,ZHANG Yue,QIAN Hao-nan,YAN Guang-rong,FAN Tian-yuan
    2021, (2):  348-354.  doi: 10.19723/j.issn.1671-167X.2021.02.020    
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    Objective: To explore the feasibility of preparing gastric floating formulations by fused de-position modeling (FDM) 3D printing technology, to evaluate the in vitro properties of the prepared FDM 3D printed gastric floating formulations, and to compare the influence of different external shapes of the formulation with their in vitro properties. Methods: Verapamil hydrochloride and polyvinyl alcohol (PVA) were used as the model drug and the excipient, respectively. The capsule-shaped and hemisphere-shaped gastric floating formulations were then prepared by FDM 3D printing. The infill percentages were 15%, the layer heights were 0.2 mm, and the roof or floor thicknesses were 0.8 mm for both the 3D printed formulations, while the number of shells was 3 and 4 for capsule-shaped and hemisphere-shaped formulation, respectively. Scanning electron microscopy (SEM) was used to observe the morpho-logy of the surface and cross section of the formulations. Gravimetric method was adopted to measure the weights of the formulations. Texture analyzer was employed to evaluate the hardness of the formulations. High performance liquid chromatography method was used to determine the drug contents of the formulations. The in vitro floating and drug release behavior of the formulations were also characterized. Results: SEM showed that the appearance of the FDM 3D printed gastric floating formulations were both intact and free from defects with the filling structure which was consistent with the design. The weight variations of the two formulations were relatively low, indicating a high reproducibility of the 3D printing fabrication. Above 800.0 N of hardness was obtained in two mutually perpendicular directions for the two formulations. The drug contents of the two formulations approached to 100%, showing no drug loss during the 3D printing process. The two formulations floated in vitro without any lag time, and the in vitro floating time of the capsule-shaped and hemisphere-shaped formulation were (3.97±0.41) h and (4.48±0.21) h, respectively. The in vitro release of the two formulations was significantly slower than that of the commercially available immediate-release tablets. Conclusion: The capsule-shaped and hemisphere-shaped verapamil hydrochloride gastric floating formulations were prepared by FDM 3D printing technology successfully. Only the floating time was found to be influenced by the external shape of the 3D printed formulations in this study.

    Mechanism of advanced glycation end products inhibiting the proliferation of peripheral blood mononuclear cells and osteoblasts in rats
    LI Zheng,WANG Xiao,HONG Tian-pei,WANG Hao-jie,GAO Zhan-yi,WAN Meng
    2021, (2):  355-363.  doi: 10.19723/j.issn.1671-167X.2021.02.021    
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    Objective: To explore the mechanism of nuclear factor-kappa B (NF-κB), phosphatidylinositol 3-kinase (PI3K)/protein kinase B(PKB/Akt) and mitogen-activated protein kinase (MAPK) signaling pathways after intervention of advanced glycosylation end products (AGEs) in peripheral blood mononuclear cells (PBMCs) and osteoblasts (OB) in rats, so as to provide certain experimental basis and theoretical basis for further research on the clinical treatment of periodontal tissue inflammation caused by diabetes mellitus. Methods: AGEs were prepared, PBMCs and OB were isolated and cultured in vitro. CCK-8 was used to detect the cell viability intervened by different concentrations and time of AGEs. Western blot and qRT-PCR were used to detect the expression changes of genes related to NF-κB, PI3K/PKB and MAPK signaling pathways. Results: OB and PBMCs were successfully isolated and cultured in vitro. The activity of PBMCs and OB cells was significantly correlated with the concentration, time and interaction of AGEs. With the increase of AGEs concentration and time, the activity of PBMCs and OB cells significantly decreased (P<0.001). AGEs stimulation significantly increased the expression of NF-κB in PBMCs and the contents of tumor necrosis factor α(TNF-α), interleukin-1β(IL-1β) (P<0.01). TNF-α, IL-1β levels were significantly reduced after inhibition of NF-κB pathway (P<0.01). NF-κB p65, JNK, and p38 phosphorylated and non-phosphorylated proteins increased significantly after AGEs stimulation of OB (P<0.05). The phosphorylated protein expression of IκB was significantly increased, while the expression of non-phosphorylated protein was decreased (P<0.01).The expressions of NF-κB p65, JNK, and IκB were significantly increased at the mRNA levels, and the expressions of IκB mRNA were significantly decreased (P<0.05). There was no difference in the expression of Akt in either phosphorylated or non-phosphorylated proteins or at the mRNA level (P>0.05). With the addition of MAPK signaling pathway inhibitors, the phosphorylation and non-phosphorylated protein expressions of NF-κB p65, p38 and JNK were significantly reduced, and the phosphorylated protein of IκB was significantly decreased and the non-phosphorylated protein was significantly increased compared with the group with AGEs alone (P<0.05). The results of qRT-PCR showed that the expression of IκB increased significantly after the addition of the JNK pathway blocker (P<0.05), and the expression of NF-κB p65, p38 and JNK decreased, but the difference was not significant (P>0.05). While NF-κB p65, p38 and JNK were significantly decreased and IκB was significantly increased in the AGEs group after the addition of the p38 pathway blocker (P<0.05). At this time, there was still no significant change in the expression of Akt at the protein level and mRNA level (P>0.05). Conclusion: AGEs inhibit the proliferation of PBMCs and OB, and the NF-κB and MAPK pathways are likely involved in regulating this process, but not the PI3K/PKB pathway.

    Efficacy of two barrier membranes and deproteinized bovine bone mineral on bone regeneration in extraction sockets: A microcomputed tomographic study in dogs
    WANG Si-wen,YOU Peng-yue,LIU Yu-hua,WANG Xin-zhi,TANG Lin,WANG Mei
    2021, (2):  364-370.  doi: 10.19723/j.issn.1671-167X.2021.02.022    
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    Objective: To evaluate the effect of two barrier membranes [multilaminated small intestinal submucosa (mSIS) and bioresorable collagen membrane (Bio-Gide)] combined with deproteinized bovine bone mineral Bio-Oss on guided bone regeneration through a canine extraction sockets model. Methods: The distal roots of 18 premolars of the Beagle’s bilateral maxillary and mandibular were removed, and 18 extraction sockets were obtained. They were randomly divided into 3 groups, and the following procedures were performed on the sockets: (1) filled with Bio-Oss and covered by mSIS (mSIS group), (2) filled with Bio-Oss and covered by Bio-Gide (BG group), (3) natural healing (blank control group). Micro-computed tomograph (Micro-CT) was performed 4 and 12 weeks after surgery to eva-luate the new bone regeneration in the sockets of each group. Results: The postoperative healing was uneventful in all the animals, and no complications were observed through the whole study period. Micro-CT analysis showed that the new bone fraction in the mSIS group and the BG group was significantly higher than that in the blank control group at the end of 4 weeks and 12 weeks (P<0.05), and more new bone fraction was observed in the mSIS group than in the BG group, but the difference was not statistically significant (P>0.05). The new bone fraction of coronal third part of the socket in the mSIS group and BG group at the end of 4 weeks were significantly higher than that of the middle and apical third part of each group (P<0.05). The values of bone mineral density were similar at 4 weeks in all the groups (P>0.05), but were significantly higher than that in the control group at the end of 12 weeks (P<0.05). The bone morphometric analysis showed that the trabecular number and trabecular spacing were significantly better in the mSIS group and the BG group than in the control group at the end of 4 weeks and 12 weeks (P<0.05), while the value in the mSIS group was slightly higher than in the BG group, but the difference was not statistically significant (P>0.05). The difference in trabecular thickness between all the groups was not statistically significant (P>0.05). Conclusion: mSIS membrane as a barrier membrane combined with deproteinized bovine bone mineral can enhance new bone formation in canine extraction sockets, similar to Bio-Gide collagen membrane.

    Effects of bioactive glass on proliferation, differentiation and angiogenesis of human umbilical vein endothelial cells
    HUANG Li-dong,GONG Wei-yu,DONG Yan-mei
    2021, (2):  371-377.  doi: 10.19723/j.issn.1671-167X.2021.02.023    
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    Objective: To investigate the effects of phytic acid derived bioactive P2O5-SiO2-CaO gel-glasses (PSC) on the proliferation, differentiation and angiogenesis of human umbilical vein endothelial cells (HUVECs) in vitro. Methods: HUVECs were cultured in PSC extracts, which were prepared with endothelial cell medium (ECM) at a gradient concentration of 0.01, 0.1, 1 and 2 g/L. Cells cultured in ECM were used as the control. The effect of PSC on HUVECs proliferation was assessed on the 1st, 3rd, 5th, 7th and 10th days with (4,5-dimethylthiazol-2-yl) 2,5-diphenyltetrazolium bromide assay (MTT), and the optimum PSC concentration for HUVECs proliferation was used in the following experiments. The subsequent experiments were divided into two groups. The experimental group used PSC extracts to culture HUVECs (PSC group) and the control group used ECM to culture HUVECs (ECM group). Gene expression of angiogenic factors, vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF), was detected on the 2nd, 4th and 7th days by real-time reverse transcription-polymerase chain reaction (real-time RT-PCR). The morphology and number of tubules formation were observed at the 4th and 10th hours. Image J software was used for counting and quantitative analysis. Results: The results of MTT assay showed that 0.1 g/L PSC group had the most significant effect on promoting HUVECs proliferation. The optical density values of 0.1 g/L PSC group on the 5th and 7th days were significantly higher than those of the other PSC groups and the control group (P<0.05). The result of real-time RT-PCR showed that 0.1 g/L PSC extract up-regulated the mRNA expression of VEGF and bFGF significantly (P<0.05). On the 4th day, the gene expressions of VEGF and bFGF in PSC group were 1.59 and 1.45 times higher than those in ECM group respectively, and on the 7th day, the gene levels of VEGF and bFGF in PSC group were 1.98 and 1.37 times higher than those in ECM group respectively. The tubule formation assay showed that the maturity and density of the tubules in 0.1 g/L PSC group was much better than that in the ECM group at the 10th hour. The quantitative analysis by Image J indicated that the tubules number in PSC group (29.63±2.29) was higher than in the ECM group (20.13±2.36), with statistical significance (P<0.05). Conclusion: PSC showed significant promoting effects on HUVECs’ proliferation, differentiation and angiogenesis in vitro.

    In vivo study of strontium-doped calcium phosphate cement for biological properties
    WANG Jing-qi,WANG Xiao
    2021, (2):  378-383.  doi: 10.19723/j.issn.1671-167X.2021.02.024    
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    Objective: To evaluate the biocompatibility and osteogenic effect of new calcium phosphate cement (CPC) in vivo and to provide experimental basis for its further clinical application. Methods: Thirty New Zealand white rabbits were randomly divided into four groups: CPC group, CPC+Bio-Oss group, Bio-Oss group and blank control group. Bone defect models of 6 mm in diameter and 7 mm in depth were made on the lateral condyle of bilateral hind legs of the rabbits. CPC, Bio-Oss and CPC+Bio-Oss mixture were implanted into the bone defect according to the group, and the mass ratio of CPC and Bio-Oss was 4 ∶1. The experimental animals were sacrificed the 4th, 12th and 24th week after operation. The tissue around the bone defect was taken for histological evaluation by H&E staining. Bone ingrowth fraction (BIF) was calculated. The expression of BMP-2 and COL-Ⅰ was detected by immunohis-tochemical staining by calculating the mean optical density (MOD) of the positive area the 4th week after operation, and the bone healing of each group was evaluated at different time points. The measurement data were analyzed by one-way ANOVA and LSD test was used for multiple comparison of the differences between the means by SPSS 19.0. P<0.05 was considered to be statistically significant. Results: The results of H&E staining showed that the BIF values of CPC group, CPC + Bio-Oss group and Bio-Oss group were significantly higher than those of blank control group at the same time point (P<0.01). The BIF values of CPC group were lower than those of Bio-Oss group and CPC + Bio-Oss group (P<0.01). There was no significant difference between CPC + Bio-Oss group and Bio-Oss group. Immunohistochemical staining showed that the MOD values of BMP-2 and COL-Ⅰ in CPC group were higher than those in blank control group, but lower than those in Bio-Oss group and CPC+Bio-Oss group (P<0.01). There was no significant difference between BMP-2 and COL-Ⅰ in CPC+Bio-Oss group and Bio-Oss group. Conclusion: The new calcium phosphate cement has good biocompatibility and can promote early osteogenesis with stable and long-term effect.

    Clinical analysis of children and adolescents emergency dental trauma cases
    YANG Xue,SUN Wei,WANG Zhe,JI Ai-ping,BAI Jie
    2021, (2):  384-389.  doi: 10.19723/j.issn.1671-167X.2021.02.025    
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    Objective: To analyze the etiological and clinical characteristics of oral emergency patients under 18 years with dental trauma, and to provide guidance on the prevention and treatment in children and adolescents. Methods: A retrospective study on the intact data of the dental trauma patients under 18 years from January 2016 to December 2018 in the Department of Oral Emergency in Peking University School of Stomatology was conducted, and the distribution of the patients’ gender, age and visiting time, as well as the number and position of traumatic teeth, diagnostic classification, and multiple injury with dental trauma were analyzed. Results: During the period, 54.2% of the first visit dental trauma patients (10 164) were children or adolescents (5 506). The two peak ages were 3-4 and 7-9 years. The incidence of the male was higher than the female in every age group (Wilcoxon test, P<0.001). From May to June and September to November, there were more cases of dental trauma. The peak time of daily dental trauma cases was from 19:00 to 20:00 (Jonckheere-Terpstra test, P<0.001). The positions of traumatic teeth in both sides were approximate symmetrical, and maxillary central incisors were the most affected. 52.3% of the patients suffered multiple teeth injuries. Among the permanent teeth trauma, enamel and dentin fracture was the most common (24.7%), followed by concussion (20.5%), sub-luxation (17.9%) and complicated crown fracture (14.4%). And among the primary teeth trauma, subluxation was the most common (31.1%), followed by concussion (14.5%) and lateral luxation (9.5%). 19.7% of the children and adolescent dental trauma patients were also suffered maxillofacial soft or hard tissue injury. Conclusion: The incidence of dental trauma in children and adolescents is higher than that in adults. There were two age peaks among the children and adolescents patients. Primary teeth and young permanent teeth were usually suffered. Clinical treatment should be considered along with the characteristics of child tooth growth. In order to prevent the occurrence of dental trauma, early orthodontic intervention should be carried out in children with severe overjet. Families, schools and nursery institutions should strengthen the protection against dental trauma.

    Blood pressure and heart rate changes of 640 single dental implant surgeries
    LIU Xiao-qiang,YANG Yang,ZHOU Jian-feng,LIU Jian-zhang,TAN Jian-guo
    2021, (2):  390-395.  doi: 10.19723/j.issn.1671-167X.2021.02.026    
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    Objective: To investigate the blood pressure and heart rate changes and influencing factors during single dental implant surgery. Methods: A retrospective cohort study was conducted. Six hundred and forty cases underwent single dental implant placement in Department of Prosthodontics, Peking University School and Hospital of Stomatology from January 2016 to December 2016 were recruited in this study according to the inclusion and exclusion criteria. They were divided into different groups according to the exposure factors which were patient characteristics (gender, age) and surgical procedures (immediate placement, flap elevation, bone grafting). The correlation between blood pressure and heart rate variability during single dental implant surgery and the patient characteristics and surgical procedures were analyzed. Results: The average systolic blood pressure variability was 9.47%±6.45% (maximum 46.04%), the average diastolic blood pressure variability was 12.18%±9.39% (maximum 88.00%), and the average heart rate variability was 10.59%±7.68% (maximum 49.12%). The effects of age and bone grafting on blood pressure variability, and of gender and immediate placement on heart rate variability, were statistically significant (P<0.05), respectively. The incidence of abnormal intraoperative blood pressure rise was 4.69%, of which there were 4 cases (0.63%) of systolic blood pressure ≥180 mmHg and/or diastolic blood pressure ≥110 mmHg. The incidence of abnormal intraoperative heart rate rise was 6.72%. Hierarchical analysis showed a higher risk of abnormal intraoperative blood pressure rise in the elderly (≥60 years) male patients [P<0.05, RR=3.409 (95%CI: 1.155-10.062) ] and flap elevation with bone grafting cases [P<0.05, RR=2.382 (95%CI: 1.126-5.040)], respectively. There was no statistically significant association between abnormal heart rate rise and patient characteristics or surgical procedures (P>0.05). Conclusion: There was a certain risk of blood pressure and heart rate variability during dental implant surgery. Elderly male patients and flap elevation with bone grafting were risk factors of abnormal intraoperative blood pressure rise.

    Three-dimentional radiographic features of 67 maxillary radicular cysts
    MENG Yuan,ZHANG Li-qi,ZHAO Ya-ning,LIU Deng-gao,ZHANG Zu-yan,GAO Yan
    2021, (2):  396-401.  doi: 10.19723/j.issn.1671-167X.2021.02.027    
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    Objective: To analyze the three-dimensional radiographic characteristics of maxillary radi-cular cysts using cone-beam computed tomography (CBCT) and spiral CT. Methods: Clinical records, histopathological reports, and CBCT or non-enhanced spiral CT images of 67 consecutive patients with maxillary radicular cysts were retrospectively acquired, and radiographic features, including size, shape, expansion, internal structure and relationship with the surrounding tissues, were analyzed. The lesions were divided into three types according to the involved tooth number, as follows: type Ⅰ (single tooth), the epicenter of the cyst was located at the apex of a nonvital tooth, without involvement of the neighbo-ring tooth; type Ⅱ (adjacent tooth involvement), the cyst was located at the apex of a nonvital tooth with involvement of the mesial and/or distal tooth root; and type Ⅲ (multi-teeth), the cyst involved the apexes of ≥4 teeth. Besides, these cysts were classified as another three types on sagittal views, as follows: centripetal, the root apex was oriented centripetally to the center of the cyst; palatal, the cyst was located mainly at the palatal side of the apex; and labial/buccal, the cyst was located mainly at the labial/buccal side of the apex. Results: Totally, 67 patients with maxillary radicular cysts were acquired, including 38 males and 29 females, and their ages ranged from 13 to 77 years. Among them, 46 lesions (68.7%) were located in the anterior maxilla and 65 (97.0%) were round or oval. Labial/buccal cortex expansion was present in 43 cases (64.2%) and palatal cortex expansion in 37 cases (55.2%). The nasal floor was invaded in 27 cases (40.3%), the maxillary sinus was invaginated in 26 cases (38.8%), and root resorption was present in 9 cases (13.4%). The average diameter of lesions was (20.89±8.11) mm mesio-distally and (16.70±5.88) mm bucco-palatally. In spite of the 4 residual cysts, the remaining 63 lesions included 14 type Ⅰ, 26 type Ⅱ and 23 type Ⅲ cysts according to the involved tooth number. Besides, the 63 lesions included 46 centripetal, 15 palatal and 2 buccal cysts on sagittal views. Conclusion: The maxillary radicular cysts were frequently well-circumscribed round or oval radiolucency, with significantly different sizes. According to the involved tooth number, it can be divided into single tooth, adjacent tooth involvement and multi-teeth types. On sagittal views, the root-cyst relationship was centripetal in most cases, while a minority of cysts expanded palatally or buccally.

    Evaluation of fracture strength of two kinds of zirconia all-ceramic crowns with different edge compensation angles
    YANG Xin,LI Rong,YE Hong-qiang,CHEN Hu,WANG Yong,ZHOU Yong-sheng,SUN Yu-chun
    2021, (2):  402-405.  doi: 10.19723/j.issn.1671-167X.2021.02.028    
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    Objective: To evaluate the effects of different edge compensation angles on the fracture strength of multilayer zirconia all-ceramic crowns and traditional uniform zirconia all-ceramic crowns. Methods: The resin tooth preparation specimen of the mandibular first molar with a knife-edge was fabricated. A 3D digital model of the specimen was obtained by scanning it with a 3D dental model scanner. The 3D digital model was imported into computer aided design (CAD) software, and three 3D digital models of the full crown with the same surface shape are designed with the edge compensation angles of 30°, 45° and 60°, respectively. Then, the designed 3D digital model is imported into computer aided manufacturing (CAM) software. Three kinds of multilayer and homogeneous zirconia all-porcelain crowns with different edge compensation angles were fabricated,10 each for a total of 60. The fracture load of each crown was measured under the electronic universal testing machine. Results: Fracture load of multilayer and uniform zirconia all-ceramic crowns, (4 322.86±610.07) N and (5 914.12±596.80) N in the 30° group, (5 264.82±883.76) N and (5 220.83±563.38) N in the 45° group and (4 900.42±345.41) N and (5 050.22±560.24) N in the 60° group, respectively. The fracture load of multi-layer zirconia all-ceramic crowns in the 30° group was significantly lower than that of homogeneous zirconia all-ceramic crowns(P<0.05); there was no statistical significance in 45° group and 60° group(P>0.05). In the multi-layer zirconia all-ceramic crowns: the fracture load of the 30° group was significantly lower than that of the 45° group (P<0.05); there was no significant difference between the 30° group and the 60° group, the 45° group and the 60° group (P>0.05).In uniform zirconia full crown group: the 30° group was higher than the 45° group, the 30° group was higher than the 60° group (P<0.05), and there was no significant difference between the 45° group and the 60° group (P>0.05). Conclusion: The fracture loads of three kinds of uniform and multilayer zirconia all ceramic crowns with different edge compensation angles can meet the clinical requirements. A smaller edge compensation angle is recommended when using traditional zirconia all-ceramic crowns, while 45° is recommended when using multi-layer zirconia all-ceramic crowns.

    Evaluation of methods for fitness of removable partial denture
    YOON Jung-min,WANG Zi-xuan,CHAN Chon-kai,SUN Yu-chun,LIU Yun-song,YE Hong-qiang,ZHOU Yong-sheng
    2021, (2):  406-412.  doi: 10.19723/j.issn.1671-167X.2021.02.029    
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    Objective: To compare the differences and indications of three evaluation methods for fitness evaluation of removable partial denture (RPD). Methods: A RPD was fabricated and seated on the stone cast of a partially edentulous mandible, and the spaces between RPD and stone cast were recorded with polyvinyl siloxane (PVS) impression material forming PVS replicas. Using cross sectional measurement, the average thicknesses of PVS replicas were measured under stereomicroscope with different numbers of selected measuring points in the denture base, major connector, occlusal rest of the RPD, and the average thicknesses of the PVS replicas measured with different numbers of measuring points were compared using one-way analysis of variance (ANOVA) and independent sample t test. Three kinds of method, including cross sectional measurement, three-dimensional analysis on the stone cast, and three-dimensional analysis on the polyether cast, were applied to measure the average thicknesses of the PVS replicas, and the average thicknesses of the PVS replicas measured by these three evaluation methods were compared with ANOVA. Results: For cross sectional measurement, statistically significant differences were found in the average thicknesses of the PVS replicas in the denture base and the major connector among the different numbers of measuring points (P<0.05), but no differences were found in the average thicknesses of the PVS replicas in the occlusal rest (P>0.05). There were significant differences among the average thicknesses of the PVS replicas measured by these three evaluation methods in each component of the RPD (P<0.01). The average thickness measured by three-dimensional analysis on the stone cast and three-dimensional analysis on polyether cast were smaller than that measured by cross sectional measurement (P<0.05). And there were no differences between the average thicknesses of PVS replicas measured by three-dimensional analysis on stone cast and three-dimensional analysis on polyether cast (P>0.05). Conclusion: For cross sectional measurement, the average thickness of the PVS replicas was influenced by the number of measuring points, and the measurement accuracy of cross sectional measurement was not reliable enough. Three-dimensional analysis on stone cast which is suitable for evaluation in vitro and three-dimensional analysis on polyether cast which is suitable for evaluation in vivo can evaluate the fitness of RPD more comprehensively and effectively than that of cross sectional measurement.

    Roles of ten eleven translocation proteins family and 5-hydroxymethylcytosine in epigenetic regulation of stem cells and regenerative medicine
    ZHAO Jian-fang,LI Dong,AN Yang
    2021, (2):  420-424.  doi: 10.19723/j.issn.1671-167X.2021.02.032    
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    The methylation of cytosine is one of the most fundamental epigenetic modifications in mammalian genomes, and is involved in multiple crucial processes including gene expression, cell differentiation, embryo development and oncogenesis. In the past, DNA methylation was thought to be an irreversible process, which could only be diluted passively through DNA replication. It is now becoming increa-singly obvious that DNA demethylation can be an active process and plays a crucial role in biological processes. Ten eleven translocation (TET) proteins are the key factors modulating DNA demethylation. This family contains three members: TET1, TET2 and TET3. Although three TET proteins have relatively conserved catalytic domains, their roles in organisms are not repeated, and their expression has significant cell/organ specificity. TET1 is mainly expressed in embryonic stem cells, TET2 is mainly expressed in hematopoietic system, and TET3 is widely expressed in cerebellum, cortex and hippocampus. This family catalyzes 5-methylcytosine to 5-hydroxymethylcytosine and other oxidative products, reactivates silenced-gene expression, in turn maintains stem cell pluripotency and regulates lineage specification. With the development of tissue engineering, organ transplantation, autologous tissue transplantation and artificial prosthesis have been widely used in clinical treatment, but these technologies have limitations. Regenerative medicine, which uses stem cells and stem cell related factors for treatment, may provide alternative therapeutic strategies for multiple diseases. Among all kinds of human stem cells, adipose-derived stem cells (ADSCs) are the most prospective stem cell lineage since they have no ethical issues and can be easily obtained with large quantities. To date, ADSCs have been shown to have strong proli-feration capacity, secrete numerous soluble factors and have multipotent differentiation ability. However, the underlying mechanism of the proliferation, secretion, acquired pluripotency, and lineage specific differentiation of ADSCs are still largely unknown. Some studies have explored the role of epigenetic regulation and TET protein in embryonic stem cells, but little is known about its role in ADSCs. By studying the roles of TET proteins and 5-hydroxymethylcytosine in ADSCs, we could provide new theoretical foundation for the clinical application of ADSCs and the stem cell-based therapy. In the future, combined with bioprinting technology, ADSCs may be used in tissue and organ regeneration, plastic surgery reconstruction and other broader fields.

    Progress in filters for denoising cryo-electron microscopy images
    HUANG Xin-rui,LI Sha,GAO Song
    2021, (2):  425-433.  doi: 10.19723/j.issn.1671-167X.2021.02.033    
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    Cryo-electron microscopy (cryo-EM) imaging has the unique potential to bridge the gap between cellular and molecular biology. Therefore, cryo-EM three-dimensional (3D) reconstruction has been rapidly developed in recent several years and applied widely in life science research to reveal the structures of large macromolecular assemblies and cellular complexes, which is critical to understanding their functions at all scales. Although the technical breakthrough in recent years, for example, the introduction of the direct detection device (DDD) camera and the development of cryo-EM software tools, made the three cryo-EM pioneers share the 2017 Nobel Prize, several bottleneck problems still exist that hamper the further increase of the resolution of single-particle reconstruction and hold back the application of in situ subnanometer structure determination by cryo-tomography. Radiation damage is still the key limiting factor in cryo-EM. In order to minimize the radiation damage and preserve as much resolution as possible, the imaging conditions of a low dose and weak contrast make cryo-EM images extremely noisy with very low signal-to-noise ratios (SNR), generally about 0.1. The high noise will obscure the fine details in cryo-EM images or reconstructed maps. Thus, a method to reduce the level of noise and improve the resolution has become an important issue. In this paper, we systematically reviewed and compared some robust filters in the cryo-EM field of two aspects, single-particle analysis (SPA) and cryo-electron tomography (cryo-ET), and especially studied their applications, such as, 3D reconstruction, visualization, structural analysis, and interpretation. Conventional approaches to noise reduction in cryo-EM imaging include the use of Gaussian, median, and bilateral filters, among other means. A Gaussian filter selects an appropriate filter kernel to conduct spatial convolution with a noisy image. Although noise with larger standard deviations in cryo-EM images can be suppressed and satisfactory performance is achieved in certain cases, this filter also blurs the images and over-smooths small-scale image features. This is especially detrimental when precise quantitative information needs to be extracted. Unlike a Gaussian filter, a median filter is based on the order statistics of the image and selects the median intensity in a window of the adjacent pixels to denoise the image. Although this filter is robust to outliers, it suffers from aliasing problems that possibly result in incorrect information for cryo-EM structure interpretation. A bilateral filter is a nonlinear filter that performs spatial weighted averaging and is more selective in the pixels allowing to contribute to the weighted sum, excluding the high frequency noise from the smoothing process. Thus, this filter can be used to smooth out noise while maintaining the edge details, which is similar to an anisotropic diffusion filter, and distinct from a Gaussian filter but its utility will be limited when the SNR of a cryo-EM image is very low. Generally, spatial filtering methods have the disadvantage of losing image resolution when reducing noise. A wavelet transform can exploit the wavelet’s natural ability to separate a signal from noise at multiple image scales to allow for joint resolution in both the spatial and frequency domains, and thus has the potential to outperform existing methods. The modified wavelet shrinkage filter we developed can offer a remarkable improvement in image quality with a good compromise between detail preservation and noise smoothing. We expect that our review study on different filters can provide benefits to cryo-EM applications and the interpretation of biological structures.

    Effect of corticotomy techniques accelerating orthodontic tooth movement on root resorption
    YANG Yuhui,HUANG Yiping,LI Weiran
    2021, (2):  434-437.  doi: 10.19723/j.issn.1671-167X.2021.02.034    
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    In recent years, developing new methods to accelerate orthodontic tooth movement (OTM) has attracted extensive attention in the field of orthodontic clinical and scientific research. It reduces orthodontic treatment time and risks. Over the past, various approaches have been done to accelerate orthodontic tooth movement. Several forms of corticotomy techniques have been effective in inducing rapid tooth movement. These techniques activate regional acceleratory phenomenon and create a favorable microenvironment for accelerating tooth movement. Root resorption is one of most common side effects of orthodontic treatment. It affects the longterm viability and health of teeth. However, the effect of corticotomy techniques accelerating orthodontic tooth movement on root resorption still remains unclear. Accelerating tooth movement may have twoside effects on root resorption. Through shortening the treatment period and removing the hyalinized tissues, the acceleration of orthodontic tooth movement could reduce root resorption. The increase of root resorption might be due to the local inflammation and function of cementoclasts/odontoclasts. In this paper, we reviewed the effects of different corticotomy techniques accelerating orthodontic tooth movement on root resorption. Corticotomy techniques deal with mucoperiosteal flaps and bone tissues differently and develop towards minimally invasive. Previous studies on root resorption use twodimensional images, including apical films and panoramic tomography, to evaluate the degree of root resorption. In recent years, researches measure the volume of root resorption accurately using conebeam computed tomography (CBCT) and microCT. Most studies suggest that the root resorption during acceleration of orthodontic tooth movement through corticotomy techniques is not statistically different from that of traditional orthodontic treatment. Some studies using microCT have shown that the root resorption in the groups of corticotomy techniques increases compared with the control group without surgery. Because of the short duration of these studies, the clinical significance is controversial on the overall impact of corticotomy techniques on orthodontic treatment. Accelerating orthodontic tooth movement is still at its emerging phase and need further research in the form of clinical trials to illustrate the effect of corticotomy techniques accelerating orthodontic tooth movement on root resorption.


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Sponsor: Peking University
Editor-in-Chief: ZHAN Qi-min
Executive Editor-in-Chief: ZENG Gui-fang
Editing and Publishing: Editorial Department of Journal of Peking University (Health Sciences)
ISSN: 1671-167X
CN: 11-4691/R