1.Fasudil inhibits Aβ1-42-induced microglial inflammatory response by inhibiting activation of NLRP3 inflammasome
Minfang GUO ; Peijun ZHANG ; Jingwen YU ; Tao MENG ; Yanhua LI ; Na LI ; Mengdi LI ; Yulu LI ; Lijuan SONG ; Jiezhong YU ; Cungen MA
Chinese Journal of Immunology 2024;40(9):1833-1837
Objective:To explore mechanism of Fasudil reducing Aβ1-42 induced BV2 cell injury based on NLRP3 inflamma-some.Methods:BV2 cells were divided into:normal control group,Aβ stimulation group,Aβ+Fasudil intervention group,Aβ+MCC950(NLRP3 inhibitor)intervention group.Cell morphology was observed under microscope.Cell activity was determined of by CCK8.NO release was measured by Griess.NLRP3,caspase 1 and IL-18 expressions were detected by immunofluorescence staining.NLRP3,ASC,caspase 1,IL-1β and IL-18 expressions were detected by Western blot.Results:Compared with normal control group,BV2 cells in Aβ stimulation group were activated and showed amoeba-like shape,cell activity was decreased,NO production was increased,NLRP3,ASC,caspase 1,IL-1β and IL-18 expressions were increased.Fasudil intervention and MCC950 intervention inhibited cell injury induced by Aβ1-42 in which BV2 cell morphology tended to be normal,cell activity was increased,while produc-tion of NO was reduced,and NLRP3,ASC,caspase 1,IL-1β and IL-18 expressions were down-regulated,there was no significant difference between Fasudil intervention group and MCC950 intervention group.Conclusion:Fasudil may alleviate Aβ1-42 induced BV2 cell injury and inflammatory reaction by inhibiting NLRP3 inflammasome activation.
2.Knock-down of ROCK2 gene improves cognitive function and reduces neuronal apoptosis in AD mice by promoting mitochondrial fusion and inhibiting its division.
Minfang GUO ; Huiyu ZHANG ; Peijun ZHANG ; Jingwen YU ; Tao MENG ; Suyao LI ; Lijuan SONG ; Zhi CHAI ; Jiezhong YU ; Cungen MA
Chinese Journal of Cellular and Molecular Immunology 2023;39(8):701-707
Objective To explore the effect of knocking down Rho-associated coiled-coil kinase (ROCK2) gene on the cognitive function of amyloid precursor protein/presenilin-1 (APP/PS1) double transgenic mice and its mechanism. Methods APP/PS1 double transgenic mice were randomly divided into AD model group (AD group), ROCK2 gene knock-down group (shROCK2 group), ROCK2 gene knock-down control group (shNCgroup), and wild-type C57BL/6 mice of the same age served as the wild-type control (WT group). Morris water maze and Y maze were employed to test the cognitive function of mice. Neuron morphology was detected by Nissl staining. Immunofluorescence histochemical staining was used to detect the expression of phosphorylated dynamin-related protein 1 (p-Drp1) and mitochondrial fusion 1 (Mfn1). Western blot analysis was used to detect the expression ROCK2, cleaved-caspase-3 (c-caspase-3), B-cell lymphoma 2 (Bcl2), Bcl2-related protein X (BAX), p-Drp1, mitochondrial fission 1 (Fis1), optic atrophy 1 (OPA1), Mfn1 and Mfn2. Results Compared with AD group mice, the expression of ROCK2 in shROCK2 group mice was significantly reduced; the cognitive function was significantly improved with the number of neurons in the hippocampal CA3 and DG areas increasing, and nissl bodies were deeply stained; the expression of c-caspase-3 and BAX was decreased, while the expression of Bcl2 was increased; the expression of mitochondrial division related proteins p-Drp1 and Fis1 were decreased, while the expression of mitochondrial fusion-related proteins OPA1, Mfn1 and Mfn2 were increased. Conclusion Knock-down of ROCK2 gene can significantly improve the cognitive function and inhibit the apoptosis of nerve cells of APP/PS1 mice. The mechanism may be related to promoting mitochondrial fusion and inhibiting its division.
Animals
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Mice
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Alzheimer Disease/pathology*
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Amyloid beta-Peptides/metabolism*
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Amyloid beta-Protein Precursor
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Apoptosis/genetics*
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bcl-2-Associated X Protein
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Caspase 3
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Cognition
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Disease Models, Animal
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Mice, Inbred C57BL
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Mice, Transgenic
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Mitochondrial Dynamics/genetics*
3.The feasibility of assessing left ventricular global and regional myocardial strain in patients with heart failure based on coronary CT angiography
Likun CAO ; Peijun LIU ; Yun WANG ; Xiao LI ; Lu LIN ; Matai ZHU ; Shenghui YU ; Yining WANG ; Zhengyu JIN
Chinese Journal of Radiology 2022;56(4):385-391
Objective:To investigate the feasibility of coronary CT angiography(CCTA)-feature tracking(FT) for assessing global and regional myocardial strain in patients with heart failure(HF).Methods:From July 2019 to December 2020, twenty-five patients diagnosed with HF from Peking Union Medical College Hospital were prospectively enrolled into the study. All patients underwent retrospective electrocardiogram-gated CCTA and cardiac MR (CMR) imaging within 7 days. CCTA-FT and CMR-FT were undertaken using cvi 42 dedicated commercial software to measure global and regional strain parameters, including global peak radial strain (GPRS), global peak circumferential strain (GPCS) and global peak longitudinal strain (GPLS), as well as peak radial strain (PRS), peak circumferential strain (PCS) and peak longitudinal strain (PLS) of left ventricular basal segment, middle segment and apical segment. Conventional left ventricular functional parameters were also calculated, including left ventricular ejection fraction (LVEF), left ventricular stroke volume (LVSV) and left ventricular mass index (LVMI). Paired t test or Wilcoxon signed-rank test was used to compare the differences of measurements between CCTA group and CMR group. Pearson or Spearman correlation analysis was used to analyze the correlation between the two groups. Inter-and intra-observer consistence in CCTA group was evaluated by intraclass correlation coefficient (ICC) analysis. Results:The effective radiation dose of CCTA examination was 6.00 (4.86,7.63) mSv. Inter-and intra-observer consistence in CCTA group was excellent, and the ICC value was 0.85-0.98. In the overall strain parameters, GPCS in CCTA group[-8.10%(-10.32%, -5.20%)] was significantly lower than that of CMR group[-8.49%(-13.79%, -5.95%)] ( Z=-2.15, P=0.031). There was no significant difference in GPRS and GPRS between the two measurement methods ( P>0.05). Strong correlations were observed between GPRS, GPCS and GPLS ( r=0.65, 0.63, 0.71,all P<0.001). For local strain parameters, PCS in the middle segment and apical segment of CCTA group were lower than those of CMR group ( Z=-2.17, -2.62, all P<0.05). There were no significant differences in PCS of basal segment, PRS and PLS of all segments between groups (all P>0.05). The PCS and PLS of basal segment, PRS of middle segment and PRS of apical segment were moderately correlated ( r=0.46, 0.52, 0.58, 0.53, P<0.05); The other local strain parameters were strongly correlated, the range of r value was from 0.64 to 0.70 (all P<0.001). For left ventricular functional parameters, LVEF, LVSV and LVMI showed no significant differences between groups ( P>0.05), and the correlation was extremely strong ( r=0.90, 0.89, 0.96, all P<0.001). Conclusions:The repeatability of CCTA-FT technique in measuring myocardial strain was good, and the correlation of parameters measured by CCTA-FT technique and CMR-FT technique was excellent. Therefore, CCTA-FT technique can be used as a new noninvasive and simple method to evaluate myocardial motor function.
4.Quantitative evaluation of extracellular volume in patients with heart failure using dual-layer spectral detector CT: a feasibility study
Peijun LIU ; Yining WANG ; Lu LIN ; Cheng XU ; Yang HOU ; Xiaomei LU ; Shenghui YU ; Yumei LI ; Yun WANG ; Zhengyu JIN
Chinese Journal of Radiology 2021;55(12):1247-1252
Objective:To explore the feasibility in evaluating segmental extracellular volume (ECV) using dual-layer spectral detector CT in patients with heart failure with various percentages of delayed hyper-enhanced volume, using MRI as a reference.Methods:Twenty-seven patients with heart failure in Peking Union Medical College Hospital were prospectively enrolled in this study from July 2019 to January 2021. All the patients underwent both CT late iodine enhancement and MR late gadolinium enhancement imaging within a week. According to percentages of hyper-enhanced volume on cardiac MR image, myocardial segments were classified into 3 groups: 0-4% (group A), 5%-49% (group B) and 50%-100% (group C). ECV images were independently observed by 2 experienced radiologists. The correlation and agreement between CT-ECV and MRI-ECV for the whole myocardial assessment and for the segmental assessment were evaluated using Spearman correlation and Bland-Altman analysis. Inter-observer agreement was assessed using the ICC.Results:Of the 27 patients, 432 segments were analyzed, with 199 segments in group A, 151 segments in group B and 82 segments in group C. In the whole myocardial analysis, the CT-ECV and MRI-ECV were 32.25% (28.04%, 34.28%) and 32.27% (28.35%, 34.77%), respectively. A good correlation was found between CT-ECV and MRI-ECV ( r=0.969, P<0.001). Bland-Altman analysis between CT-ECV and MRI-ECV showed a small bias (0.4%), with 95% limits of agreement of -6.9% to 7.8%. as for the segmental myocardial assessment, the CT-ECV was 28.23% (26.18%, 29.92%) for group A, 33.29% (30.16%, 35.96%) for group B and 40.22% (34.06%, 46.70%) for group C. There was statistically significant difference in ECV among three groups (all P<0.001). Good correlations between CT-ECV and MRI-ECV were found in group A ( r=0.614, P<0.001), group B ( r=0.852, P<0.001) and group C ( r=0.953, P<0.001). Bland-Altman analysis between CT-ECV and MRI-ECV showed a small bias 2.0% (95% limits of agreement:-17.6%-21.6%) in group A, a small bias -0.4% (95% limits of agreement: -13.8%-12.9%) in group B and a small bias -1.8% (95% limits of agreement: -17.4%-13.9%) in group C. The ICC values between 2 observers were 0.877 and 0.945 on CT-ECV and MRI-ECV, respectively. Conclusions:The larger percentage of hyper-enhanced volume on cardiac MR image, the stronger correlation are between the CT-ECV and MRI-ECV. CT-ECV may be taken as an alternative tool for quantitative evaluation of myocardial tissue in patients with heart failure.
5.Efficacy and safety study of Chinese botulinum toxin A 100U in patients with overactive bladder: a prospective, multicenter, double-blind and randomized controlled trial
Limin LIAO ; Huiling CONG ; Zhihui XU ; Enhui LI ; Zhiliang WENG ; Haihong JIANG ; Ben LIU ; Xiao HUANG ; Shujie XIA ; Wei WEN ; Juan WU ; Guowei SHI ; Yang WANG ; Peijun LI ; Yang YU ; Zujun FANG ; Jie ZHENG ; Ye TIAN ; Haodong SHANG ; Hanzhong LI ; Zhongming HUANG ; Liqun ZHOU ; Yunxiang XIAO ; Yaoguang ZHANG ; Jianlong WANG ; Xiaodong ZHANG ; Peng ZHANG ; Dongwen WANG ; Xuhui ZHANG ; Keji XIE ; Bin WANG ; Lulin MA ; Xiaojun TIAN ; Lijun CHEN ; Jinkai DONG
Chinese Journal of Urology 2021;42(6):414-422
Objective:To assess the efficacy and safety of 100 units of botulinum toxin A (BTX-A) intradetrusor injection in patients with overactive bladder.Methods:From April 2016 to December 2018, 17 tertiary hospitals were selected to participate in this prospective, multicenter, randomized, double-blind, placebo-controlled study. Two phases of study were conducted: the primary phase and the extended phase. This study enrolled patients aged 18 to 75 years who had been inadequately managed by anticholinergic therapy (insufficient efficacy or intolerable side effects) and had spontaneous voiding with overactive bladder. Exclusion criteria included patients with severe cardiac, renal and hepatic disorders, patients with previous botulinum toxin treatment for 6 months or allergic to BTX-A, patients with urinary tract infections, patients with urinary stones, urinary tract tumors, diabetes mellitus, and bleeding tendency. Eligible patients were randomly assigned to BTX-A group and placebo control group in a ratio of 2∶1. Two groups of patients received 20 intradetrusor injections of BTX-A 100U or placebo at the depth of the submucosal muscle layer respectively under cystoscope, including 5 injections at the base of the bladder, 3 injections to the bladder triangle, 5 injections each to the left and right walls and 2 injections to the top, sparing the bladder neck. As a placebo control group, patients received same volume of placebo containing no BTX-A and only adjuvant freeze-dried preparations for injection with the same method. A combination of gelatin, sucrose, and dextran served as adjuvants. Average micturition times per 24 hours, urinary incontinence (UI) episodes per day, average micturition volume per day, OAB symptom score(OABSS), and quality of life (QOL) score were recorded at baseline and the 2nd, 6th and 12th week after treatment. The primary efficacy endpoint was the change from baseline in the average micturition times per 24 hours at the 6th week after treatment. The secondary efficacy endpoints included the change from baseline in the average micturition times per 24 hours at 2nd and 12th week, as well as the change from baseline in the OABSS, QOL score, average frequency of urgency and UI episodes per day, urgency score, average micturition volume per day at 2nd, 6th and 12th week after treatment. Patients were followed for 12 weeks to assess adverse events (AEs). After assessed at week 12, if the micturition times has decreased less than 50% compared to baseline and the patient is willing to receive retreatment, then patients could enter the extended trial phase. In that phase, patients in both groups were injected with 100 units BTX-A from 12th week onwards and then followed up the same indicators for 12 weeks.Results:216 patients were enrolled in this trial (144 cases in the BTX-A group and 72 cases in the placebo control group). Baseline characteristics such as age (47.75±14.20 in the BTX-A group and 46.39±15.55 in the control group), sex (25 male/117 female in the BTX-A group and 10/61 in the control group), and disease duration (0.51 years in the BTX-A group and 0.60 years in the control group) were balanced between the two groups( P>0.05). A marked reduction from baseline in average micturition times per 24 hours was observed in all treatment groups at the 6th week and the reduction of the two groups was statistically different ( P<0.001 and P=0.008 respectively). Compared with the baseline, the average micturition times per 24 hours at the 6th week decreased from baseline by 2.40(0.70, 4.60)times for the BTX-A group and 0.70(-1.00, 3.30) times for the placebo control group respectively, and the difference between the two groups was considered to be statistically significant ( P=0.003). The change rates of average micturition times per 24 hours from baseline at the 6th week of the two groups were (16±22)% and (8±25)% respectively, and the difference between the two groups was statistically significant ( P=0.014). Compared with the baseline, the average micturition times per 24 hours at 2nd and 12th week decreased by 2.00(0.00, 4.00)and 3.30(0.60, 5.03)for the BTX-A group, 1.00(-1.00, 3.00)and 1.70(-1.45, 3.85)for the placebo control group respectively. The difference between two groups was considered to be statistically significant ( P=0.038 and P=0.012); the changes of average urgency times per day for the BTX-A group and the control group at the 2nd, 6th and 12th week were 2.00(0.00, 4.30)and 2.40(0.30, 5.00), 3.00(0.30, 5.70)and 0.70(-1.30, 2.70), 0.70(-1.30, 3.00) and 1.35(-1.15, 3.50), respectively. There were significant differences between two groups at the 2nd, 6th and 12th week, ( P=0.010, P=0.003 and P=0.025, respectively). The OABSS of the BTX-A group and the control group at the 6th week decreased by 1.00(0.00, 4.00)and 0.50(-1.00, 2.00) compared with the baseline, and the difference between the two groups was statistically significant ( P=0.003). 47 cases of BTX-A group and 34 cases of placebo control group entered the extended trial phase, and 40 and 28 cases completed the extended trial phase, respectively. The average micturition volume per 24 hours changed by -16.60(-41.60, -0.60)ml and -6.40(-22.40, 13.30)ml, (-35.67±54.41)ml and(-1.76±48.69)ml, (-36.14±41.51)ml and (-9.28±44.59)ml, (-35.85±43.35)ml and(-10.41±40.29)ml for two groups at the 12th, 14th, 18th and 24th week, and the difference between two groups was statistically significant at each follow-up time ( P=0.01, 0.006, 0.012 and 0.016, respectively). There was no significant difference in other parameters( P>0.05). However, adverse reactions after intradetrusor injection included increased residual urine volume (27 in the BTX-A group and 3 in the control group), dysuria (21 in the BTX-A group and 6 in the control group), urinary infection (19 in the BTX-A group and 6 in the control group), bladder neck obstruction (3 in the BTX-A group and 0 in the control group), hematuria (3 in the BTX-A group and 1 in the control group), elevated alanine aminotransferase (3 in the BTX-A group and 0 in the control group), etc. During the follow-up period, there was no significant difference in the other adverse events between two groups except the increase of residual urine volume( P<0.05). In the primary trial phase, among the 27 cases with increased residual urine volume in BTA group, only 1 case (3.70%) with PVR more than 300 ml; the PVR of 3 patients in the placebo group was less than 100 ml. The increase of residual urine volume caused by the injection could be improved or disappeared with the passage of time. Conclusions:Intradetrusor injection of Chinese BTX-A improved the average micturition times per 24 hours, the average daily urgent micturition times, OABSS, and average micturition volume per time, and reduced the adverse effects in patients with overactive bladder.Chinese BTX-A at dose of 100U demonstrated durable efficacy and safety in the management of overactive bladder.
6.Feasibility of high concentrated contrast media combined with monochromatic images to improve image quality with double low scanning in dual-layer spectral coronary CT angiography
Peijun LIU ; Yining WANG ; Yang JIAO ; Xiaomei LU ; Shenghui YU ; Yan YI ; Cheng XU ; Hongling FAN ; Yun WANG ; Yun LIN ; Zhengyu JIN
Chinese Journal of Radiology 2020;54(6):514-520
Objective:To evaluate the feasibility of high concentrated contrast media combined with monochromatic images to improve image quality with double low scanning in dual-layer spectral coronary CT angiography.Methods:Fifty-six patients with suspected coronary artery disease were enrolled and randomly separated into two groups. All patients were scanned at 120 kVp in step-and-shoot mode using a dual-layer detector CT (IQon spectral CT). Patients were either injected with 18 ml high concentration contrast medium(400 mgl/ml) at 2 ml/s (group A) or 45 ml contrast medium (370 mgl/ml) at 4 ml/s (group B). Forty to 80 keV monoenergetic images with 10 keV increment and conventional image (group A2) were reconstructed for group A, conventional poly-energetic image was reconstructed for group B. Region of interest was placed on aorta root (AO), middle segment of left anterior descending (LAD), left circumflex (LCX) and right coronary artery (RCA) to measure the attenuation and noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). Image quality was assessed by two reviewers independently with a 4-point scale on image quality (1-undiagnostic,4-excellent). The objective and subjective image evaluation were compared using the Kruskal-Wallis test. The Steel Dwass was used for multiple comparisons between monoenergetic images in Group A and conventional images in Group B, after the Kruskal-Wallis test.Results:There were significant differences among the attenuation, noise, SNR and CNR of group B, group A2, and monoenergetic images(all P<0.001).The CT value in the aortic root was significantly higher at 40-50 keV monoenergetic images than that in group B(all P<0.05), and similarly, the CT value in LAD,LCX and RCA at 40 keV were superior than that in group B(all P<0.001). There was no significant difference in the noise of the aortic root among 40 keV image, group A2 and group B(all P>0.05),while the noise in the 50-80 keV monoenergetic images were significantly lower than that in Group B(all P<0.001). The SNR and CNR in the aortic root were significantly higher at 40-60 keV monoenergetic images than that in group B(all P<0.001).The SNR in LAD and RCA at 40,50 keV and the CNR in LAD and RCA at 40-60 keV were higher than that in group B(all P<0.01).The SNR at 40-60 keV and CNR at 40-70 keV in LCX were superior than that in group B(all P<0.05). There were significant differences among the subjective image quality score of group B, group A2, and monoenergetic images(all P<0.001).The subjective image quality score of 40,50 keV images were not significantly different from that in group B (all P>0.05),while the score in 60-80 keV image and group A2 were lower than that of Group B(all P<0.001). Conclusion:40,50 keV low monochromatic images derived from dual-layer spectral detect CT combined with high concentrated contrast media can provide comparable or superior image quality with double low scanning in CCTA study.
7.Clinical characteristics and treatment of traumatic renal artery thrombosis
Guangyong LI ; Yu GAO ; Chao ZHANG ; Xiaobo YANG ; Haifeng WU ; Peijun LI ; Fubao CHEN
Chinese Journal of Geriatrics 2018;37(8):901-903
Objective To investigate the clinical characteristics,early diagnosis,and rational treatments of traumatic renal artery thrombosis or other traumatic emboli.Methods We summarized the clinical data of 10 patients with traumatic renal artery thrombosis or other traumatic emboli.Results Six of ten patients had left renal artery thrombosis,while four of the ten patients had right renal artery thrombosis.Ultrasonography reported a reduced blood flow signal in one patient,and then renal artery embolism was confirmed by enhanced CT.The other nine patients were directly definitely diagnosed as renal artery embolism by enhanced CT.Four patients were treated with low molecular weight heparin calcium,in whom the CT follow-up showed no obvious blood reperfusion in injured kidneys,but the renal function was in normal range.Renal hypertension occurred in two patients,and one of them received nephrectomy because of poorly controlled hypertension with medication.Conclusions Clinical symptoms,signs and laboratory examinations show no specific findings for diagnosis of traumatic renal artery thrombosis.The color Doppler ultrasound is a preliminary screening method for,and an enhanced CT scan is an effective method for,diagnosis of renal artery thrombosis.The early recovery of renal blood circulation is an evidence of effective treatment.Major concerns are supposed to focus on renal function and blood pressure during followup.
8.Comparative study of self-ligating brackets and conventional brackets:direction and progress
Yu LIU ; Peijun WANG ; Shan ZHOU ; Xuefei BAI
Chinese Journal of Tissue Engineering Research 2014;(25):4068-4072
BACKGROUND:The self-ligating bracket is superior to the conventional bracket in orthodontic treatment, but there are a lot of controversies. At present, researchers have different views on the function of self-ligating brackets. OBJECTIVE:To summarize the comparative study of self-ligating brackets and conventional brackest with the direction and development in recent years. METHODS:A computer-based search of PubMed (2000-2014) and CNKI (2000-2014) databases was done for relevant articles, using the key words of “self-ligating brackets; conventional orthodontic brackets” in English and Chinese, respectively. RESULTS AND CONCLUSION:Self-locking brackets saves chair side time, which has been confirmed and accepted. There are different views for the issue that self-ligating brackets can reduce friction in orthodontic treatment. It is widely accepted that, the self-ligating brackets using thin round wire had less friction than the conventional brackets; whether the friction of self-ligating brackets in the closed gap and fineness adjustment stages is less than the conventional brackets stil remains unclear, which need further clinical comparative studies. The self-ligating brackets showed no significant difference with the conventional brackets in arch expansion, reducing anchorage loss and root adsorption. The majority of relevant studies is performedin vitro, and cannot exactly simulate the dental conditions. A large-size experiment with the uniform criteria for therapeutic efficacy is needed to objectively evaluate self-ligating brackets.
9.Heat treatment effect on the fatigue fracture cycle of buccal multiloop
Xuefei BAI ; Peijun WANG ; Shiqian XU ; Lu HOU ; Yu LIU
Chinese Journal of Tissue Engineering Research 2014;(47):7597-7602
BACKGROUND:Buccal Multiloop Removable Appliance can interceptively correct mutiple adolescent malocclusions. But the clinical problem of Buccal Multiloop fatigue fracture is not solved yet. How to prolong the fatigue fracture cycle is stil in the research stage. OBJECTIVE: To study the effect of different temperature of heat treatment on the Buccal Multiloop fatigue fracture cycle, thereby to select a relatively optimal method to enhance the fatigue fracture cycle. METHODS: Thirty-five left HL-2 Buccal Mltiloops were divided into seven groups according to different ways of heat treatment. Each group consisted of five samples. They were an untreated group, three pre-bending groups (320, 420, 520℃ heat treatment before bending) and three post-bending groups (320, 420, 520℃ heat treatment after bending). The dental stainless steel wires and Buccal Multiloop were respectively treated by low-temperature annealing. The data were recorded and evaluated after the samples tested by the 3D Simulating Movement of TMJ Testing Machine. The features of fatigue fracture were observed by scanning electron microscope. RESULTS AND CONCLUSION: The mean values of the Buccal Multiloop fatigue fracture cycle from largest to smalest were as folows: 520℃ pre-bending group > 420℃ pre-bending group > 320℃ pre-bending group > untreated group > 520℃ post-bending group > 320℃ post-bending group > 420℃ post-bending group. The fatigue fracture cycle of Buccal Multiloop made of the dental stainless steel wires after 520℃ annealing treatment was longer than others. By the observation of scanning electron microscope, the fracture crack extension area had the tendency to expand, transient interruption was delayed and the tissue structure became more uniform.
10.Research on a rat model of female stress urinary incontinence
Guangyong LI ; Haifeng WU ; Yang YU ; Zhiyong LYU ; Hongbin SHI ; Peijun LI ; Fubao CHEN
Chinese Journal of Geriatrics 2014;33(9):1018-1020
Objective To investigate the pathological changes and mechanism in the urethra by parturition-induced stress urinary incontinence.Methods Sprague Dawley female rats underwent vaginal balloon dilation for 4 hours immediately after delivery.One week later,the rats were anesthetized and both ovaries were excised.Then a rat model of stress urinary incontinence (SUI) was successfully established.One month after ovariectomy,conscious cystometry and Leak-Point Pressure (LPP) were measured by MP150.Histological examination and Western blotting were performed after functional assays.Results (1) 85% of rats presented astress urinary incontinence in the model group.(2) The urethras in SUI rats had decreased muscles,and striated muscles showed fragmentized and disorganized.(3) Elastic fibers were long,well organized and tightly connected to the muscle bundles in sham group,while elastic fibers showed fragmentation and disorganization in the model group.(4) The protein expression of vascular endothelial growth factor (VEGF) and blood vessels were reduced in SUI rats as compared with the sham rats.Conclusions Muscle and elastic fibers in the urethra are disrupted in SUI rat.VEGF may play an important role in regulation of pathological changes in urethra.

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