1.The effects of orbital bone density on the stress distribution of implant-bone surface:A 3D finite element study
Xing ZHANG ; Ying LIU ; Songling CHEN ; Yun ZHANG ; Jianling CHEN
Journal of Practical Stomatology 2016;32(4):501-505
Objective:To observe the effects of orbital bone density on the stress distribution of implant-bone surface.Methods:The 3D finite element analysis craniofacial model with eight HU values(300 -1 0 000)was established.A force of 20 N along the im-plant axis was applied on the model.The stress values and distribution were calculated and analyzed.Results:The peak of stress val-ue and displacement discreased as HU value increased.In the range of HU value 800 -1 000 HU,the peak of stress value and dis-placement of bone interface did not significantly change with the increasing of HU value.Conclusion:Orbital bone density is an im-portant factor on orbital implant failure when HU value below 800.
2.Analysis of normal high-frequency ultrasonographic anatomical features of tarsal tunnel
Xing HUA ; Guangxing CHEN ; Yun HE ; Yanli GUO ; Xueyan DENG
Journal of Regional Anatomy and Operative Surgery 2014;(2):128-130
Objective To analyze the features of normal high-frequency ultrasonography of tarsal tunnel. Methods Forty volunteers (20 males and 20 females) were examined with high-frequency ultrasound (12 MHz). The tendons,nerve and blood vessels in tarsal tunnel were observed from short-axis and long-axis views dynamically. The areas of tarsal tunnel and posterior tibial nerve were measured and com-pared between the males and females. Results High-frequency ultrasonography depicted the anatomical structure of tarsal tunnel,and the tendons,nerve and blood vessels presented different sonographic features that were easy to differentiate. The area of tarsal tunnel: male (7.61 ±1.00) cm2,female (6. 61 ± 1. 07) cm2 (P <0. 01). The area of posterior tibial nerve: male (9. 59 ± 0. 75) mm2,female (8.91 ±0.74) mm2(P<0.01). Conclusion High-frequency ultrasonography can clearly show and accurately measure the tarsal tunnel structure. To be familiar with the normal ultrasonographic anatomy of tarsal tunnel will help to improve the efficacy of ultrasound diagnosis of tarsal tunnel abnormalities.
3.The effects of orbital implant shrink range on the stress distributions in bone-implant interface
Xing ZHANG ; Songling CHEN ; Yun ZHANG ; Daiying HUANG
Journal of Practical Stomatology 2014;(4):535-537
Objective:To observe the effect of orbital implant shrink range on the stress distribution in bone-implant interface. Methods:The 3D finite element analysis of craniofacial and orbital implant models with the implant length of 3,4,6 and 10 mm,and with the shrink range of0.05,0.1 and 0.15 mm were established respectively.The stress in the bone-implant interface were calculat-ed and analyzed.Results:The stress increased with the increase of implant shrink range.The stress produced by the implant with 0.15 mm shrink range decreased.The stress of the implant of 10 mm was lower than that of other implants with the shrink range of 0.1 and 0.15 mm.Conclusion:The maximal implant shrink range of 0.1 mm in the model can meet the clinical requirements in orbital implant planning.
4.Three-dimensional finite element analysis of the effect of orbital implant lengths on stress distributions in peri-implant surfaces.
Xing ZHANG ; Songling CHEN ; Yun ZHANG ; Liuying QI
West China Journal of Stomatology 2014;32(5):484-487
OBJECTIVEThis study aims to observe the effect of orbital implant lengths on stress distribution in peri-implant surfaces.
METHODSThe three-dimensional finite element analysis models of craniofacial and orbital implants with a diameter of 3.75 mm and lengths of 3, 4, 6, and 10 mm were established. A force of 20 N was applied to the models. The stress and displacement distribution under every condition were recorded and analyzed.
RESULTSThe loading direction along the implant axis and the stress concentration on the implant root were observed. The loading direction was at a 45 degree angle relative to the implant axis, and the stress concentration was located at the implant neck and the first screw thread. The maximum stress of the 3 mm implant was significantly higher than that under the other two loading directions. The maximum displacement of the four lengths exhibited no significant change. Given the same implant length, stress, and displacement, the peak of the implant axial direction was lower than that of the 45 degree direction. The loading type was an important factor influencing the stress and displacement of peri-implant bones.
CONCLUSIONThe implants of more than 4 mm length can be considered for clinical use. The implant of 3 mm length should be implanted in a region with thicker cortical bone.
Biomechanical Phenomena ; Dental Implants ; Dental Prosthesis Design ; Dental Stress Analysis ; Finite Element Analysis ; Orbital Implants ; Stress, Mechanical
6.The microRNA-21-5p regulation of type Ⅱ alveolar epithelial cell apoptosis
Ying HE ; Yun CHENG ; Lei SHI ; Zhouxiong XING ; Miao CHEN
Chinese Critical Care Medicine 2021;33(3):344-348
Objective:To explore whether microRNA-21-5p (miR-21-5p) has the effect of anti-apoptosis of human alveolar typeⅡ epithelial cells (ATⅡ).Methods:ATⅡ cells derived from the human were cultured in vitro and used for experiments when the cells were grown until the presence of lamellar bodies and microvilli were observed by light microscope. The cells were divided into blank control group (direct culture), hydrogen peroxide (H 2O 2) injury group (cultured with 0.5 mmol/L H 2O 2), and miR-21-5p overexpression group (using miR-21-5p with a multiplicity of infection (MOI) of 100 lentiviral overexpression vector with 0.5 mmol/L H 2O 2) and miR-21-5p empty virus control group (miR-21-5p lentiviral blank vector was co-cultured with 0.5 mmol/L H 2O 2). In each group, cell proliferation was detected by cell counting kit-8 (CCK-8) at 0, 12, 24, 36, and 48 hours of cell culture; cell apoptosis was detected by flow cytometry at 24 hours of culture. Results:① Cell proliferation activity test results: with the extension of cell culture time, the cell proliferation activity of the blank control group gradually increased, while the cell proliferation activity gradually decreased after the addition of 0.5 mmol/L H 2O 2. However, the cells proliferation activity in the miR-21-5p overexpression group decreased more slowly than that in the H 2O 2 injury group and the miR-21-5p empty virus control group, and the cell proliferation activity at 48 hours was significantly higher than the H 2O 2 injury group and the miR-21-5pempty virus control group ( A value: 0.295±0.005 vs. 0.184±0.005, 0.169±0.002, both P < 0.05). It showed that both H 2O 2 and lentivirus accelerated cell damage, while miR-21-5p could reduce cell apoptosis. ② Apoptosis rate test results: compared with the blank control group, the apoptosis rate increased significantly after adding 0.5 mmol/L H 2O 2; while the apoptosis rate of the miR-21-5p overexpression group was lower than that of the H 2O 2 injury group and miR-21-5p empty virus control group [early apoptosis rate: (14.31±0.12)% vs. (24.50±0.12)%, (23.41±0.13)%; late apoptosis rate: (8.12±0.13)% vs. (9.71±0.11)%, (10.41±0.15)%; overall apoptosis rate: (22.33±0.12)% vs. (34.21±0.10)%, (33.82±0.14)%; all P < 0.05], which further proved that miR-21-5p had anti-apoptotic effects. Conclusion:miR-21-5p has an anti-apoptotic effect on human ATⅡ.
7.Relationship between Motor Function and Balance for Spastic Hemiplegia after Stroke
Yixiong CHEN ; Yingying NI ; Weijian CHEN ; Yun ZHANG ; Chengyao QIU ; Yunyi LIU ; Zhongrui FENG ; Xing CHEN
Chinese Journal of Rehabilitation Theory and Practice 2010;16(6):576-578
ObjectiveTo discuss the relationships among spastic paralysis and motor function, balance function and other clinical variables after stroke.MethodsAssessed the clinical spastic index of hemiplegic lower limbs with CSI scale, motor function with Fugl-Meyer Assessment, and balance function with Berg Equilibrium Scale, respectively. And then analyzed the relationship between clinical spasm index with motor function, balance function of the hemiplegic lower limbs with Pearson correlation analysis. Finally, ascertained which was the most important factor affecting the clinical spasm index of spastic lower limbs with stepwise regression analysis.ResultsThere is negative correlation between clinical spasm index with motor function and balance function, respectively. Tendon reflex, muscular tension and clonus are the deciding factors to motor function(P<0.05) and balance function(P<0.05) of the hemiplegic lower limbs.ConclusionThe clinical spasm index of hemiplegic limbs can affect the recovery of motor function and balance function significantly. So, assessing and improving the clinical spasm index of paralytic lower limbs can optimize the rehabilitation program to stroke patients.
8.The effect of orbital implant load angle on the stress distributions of peri-implant surface
Xing ZHANG ; Songxin XIA ; Songling CHEN ; Jianling CHEN ; Yun ZHANG ; Liuying QI
Journal of Practical Stomatology 2015;(2):237-240
Objective:To observe the effect of orbital implant load angle on the stress distribution of peri-implant surface.Methods:The 3D finite element analysis model of orbital implant with diameter of 3.75 mm and length of 6 mm was established.A force of 20 N was applied on the model at various angles.The stress distribution and displacement of the implant were recorded and analyzed.Results:Under 0°,1 0°,20°,30°,45°and 90°the maximum stress(MPa)on the peri-implant surface was 3.1 73,6.535,1 0.506,1 4.1 68, 1 8.949 and 24.755,the maximum displacement(μm)of the implant was 1 .761 ,3.654,7.665,1 1 .567,1 6.774 and 25.072,respec-tively.Conclusion:The loading angle is an important factor influencing stress and displacement of peri-implant bone.
9.Study on the homology of imipenem-resistant Acinetobacter baumannii and the genotype of carbapenemase
Xiao-Xing DU ; Xing-Guo ZHANG ; Hua ZHOU ; Yun-Song YU ; Ya-Gang CHEN ; Lan-Juan LI ;
Chinese Journal of Infection and Chemotherapy 2006;0(04):-
Objective To characterize the antibiotic resistance,homology and carbapenemase genotypes of imipenem resistant Acinetobac1ter baumannii isolated from our hospital,and analyze the clonal relatedness of the test strains.Methods Ninety five strains of imipenem resistant A.baumannii were isolated from August 2003 to December 2004 in the First Affiliated Hospital, College of Medicine,Zhejiang University.The MICs of 16 antimicrobial agents against these strains were determined by agar dilution and E-test method.The homology of these isolates was analyzed by pulse-field gel electrophoresis(PFGE).The coding gene of carbapenemases was amplified.PCR products were purified,cloned and sequenced.Plasmid DNA was extracted and purified.Conjugation and Southern blot were performed to locate the position of oxa 23 gene.Results The resistance rates to ampicillin-sulbactam and cefoperazone sulhactam were 67.9% and 30.2%.Polymyxin E had the lowest resistance rate of 17%. The resistance rate to other antimicrobial agents was higher than 90%.The 95 strains,isolated from 10 clinical units,were classified into 6 clones.Clones A and B were predominant clones.All strains produced carbapenemases which were confirmed as OXA 23 by PCR and sequencing analysis.No plasmid was extracted and conjugation was not successful.Southern bolt showed that oxa-23 gene was located on Apal-digested chromosomal segments about 220 kb and 200 kb in Clones A and B,re spectively.Conclusions OXA 23-producing A.baumannii has become one of the most important multi-resistant pathogens in our hospital.Clones A and B have widely spread in our hospital.Oxa-23 gene is located on chromosomal DNA.
10.Plasmid-mediated carbapenemase KPC-2 in a strain of Klebsieila pneumoniae
Xing-Guo ZHANG ; Xiao-Xing DU ; Rong ZHANG ; Ze-Qing WEI ; Yun-Song YU ; Ya-Gang CHEN ; Lan-Juan LI ;
Chinese Journal of Laboratory Medicine 2003;0(09):-
Objective To investigate the resistant mechanism of imipenem-resistant K. pneumoniae.Methods The minimal inhibitive concentrations (MICs) of the antimicrobial agents were determined by Etest.Isoelectric focusing electrophoresis (IEF),plasmid extraction,conjugation, transformation,PCR amplification,cloning and sequencing were carried out for analyzing the encoding gene of ?-1actamases.Results Three kinds of ?-1actamases were detected with pIs of 7.2,6.7,and 5.4.in a clinical strain of K.pneumoniae.These ?-1actamases were TEM-I (pI,5.4),SHV-12 (pI,8.2) and KPC-2 ( pI,6.7 ) confirmed by sequencing of the PCR products.Only one band of ?-1actamase with pI 6.7 was displayed in the transformant.A 1500 bp segment,which contained the KPC-2 gene confirmed by nucleotide sequence analysis,was cloned from a 60 000 bp plasmid of the transformant.Conclusion The strain of K.pneumoniae resistant to imipenem produces a plasmid-mediated carbapenemase KPC-2 which belongs to Bush group 2f,class A ?-1actamase.