Structural design and mechanical property analysis of trabecular scaffold of triply periodic minimal surface with a radial gradient / 中国组织工程研究

BACKGROUND:The elastic modulus of traditional bone implants is large and does not match the elastic modulus of human bone,which will cause a stress shielding effect and lead to bone resorption.The trabecular scaffold of the triply periodic minimal surface with radial gradient has elastic modulus matching with human cancellous bone,and its yield strength is greater than that of human cortical bone,which provides a new choice for the design of bone scaffold. OBJECTIVE:Triply periodic minimal surface structure with radial gradient was constructed by the implicit surface method.The sample was manufactured by laser selective melting technology,and the quasi-static compression test was carried out to obtain trabecular scaffolds with mechanical properties matching human bones. METHODS:Four types of the trabecular scaffolds of the triply periodic minimal surface with a radial gradient of G,I,P and D were established by the implicit surface method.Samples were manufactured by laser selective melting technology.We observed the surface morphology of the molded sample,evaluated the molding quality,conducted a quasi-static compression test,and evaluated the mechanical properties of the samples. RESULTS AND CONCLUSION:The quasi-static compression test results showed that compared with the four triply periodic minimal surface scaffolds,the platform stress of the G scaffold had less fluctuation and no failure or fracture,indicating that the G scaffold had the best plasticity.The mechanical properties of the G scaffolds with 45%,55%and 65%porosities were analyzed.It was found that the elastic modulus of G scaffolds with 55%porosity was within the range of elastic modulus of human cancellous bone(0.022-3.7 GPa),and the yield strength was close to the maximum yield strength of human cortical bone(187.7-222.3 MPa).In conclusion,G triply periodic minimal surface scaffold with 55%porosity can reduce the stress shielding effect,bear a higher body load,improve the stability of the implant,and prolong the service life of the implant.

Effect of restored height on neighboring vertebrae after vertebral body strengthening:a finite element analysis / 中国组织工程研究

BACKGROUND:Vertebral compression fracture is a common disease in the current orthopedic field.However,the occurrence of re-fracture in neighboring vertebrae after surgery is a problem that cannot be ignored,which has a serious impact on the normal life of patients. OBJECTIVE:The aim of this study is to establish four postoperative models with different recovery heights using computed tomography images.By using finite element analysis,we derived the stresses on the neighboring vertebrae at different recovery heights and further explored the importance of postoperative recovery of the height of the injured vertebrae. METHODS:A finite element model of the thoracolumbar spine(T11-L3)was established and validated,on the basis of which four postoperative finite element models of L1 with different recovery heights of 100%,80%,60%,and 40%were constructed,in which the cement capacity varied with the recovery height.The specific models are as follows:Model 1 was the postoperative model with normal recovery height,and the cement capacity was 8.3 mL.Model 2 was the postoperative model in which 20%of the anterior height of the L1 was removed and the posterior convexity angle became 10.41°,and the cement capacity was 6.9 mL.Model 3 was the postoperative model in which 40%of the anterior height of the L1 was removed and the posterior convexity angle became 20.17°,and the cement capacity was 4.7 mL.Model 4 was a postoperative model with 60%of the L1 anterior height removed and the posterior convexity angle changed to 28.85°,with a cement capacity of 3.6 mL.For evaluation of the postoperative model,we applied a moment of 7 Nm and an axial force of 500 N.The followings were recorded and analyzed:peak stresses in the L2 upper endplate and T12 lower endplate;peak stresses in the L2 and T12 cancellous bone. RESULTS AND CONCLUSION:(1)The highest peak stresses for each condition of the L2 upper endplate,T12 lower endplate,L2 cancellous bone,and T12 cancellous bone occurred in Model 1 and Model 4.In particular,the T12 lower endplate,except for the posterior extension condition,the anterior flexion,left and right lateral bending,and left and right rotation conditions all reached their highest peak stresses in Model 4,with stresses of 50.3,33.1,44.9,34.3,and 31.9 MPa.(2)Based on the peak stresses in the adjacent vertebral endplates and cancellous bone,after excluding Model 1 and Model 4,the minimum peak stresses for most of the conditions appeared in the Model 2,and the minimum peak stresses appeared in the Model 2 in 66.6%of the cases,especially in the upper endplates of the L2 and cancellous bone except for the posterior extension condition,the minimum peak stresses all appeared on the Model 2.(3)Therefore,controlling the recovery height at about 100%and 40%of the original height was a dangerous recovery height,which had a greater impact on the neighboring vertebrae.Controlling the recovery height at about 80%of the original height may be a more ideal choice.With a recovery height of about 80%of the original height,the adjacent vertebrae are subjected to less stress,thus reducing the risk of re-fracture of the adjacent vertebrae in the patient.

Acoustic analysis in patients with unilateral arytenoid dislocation and unilateral vocal fold paralysis / 临床耳鼻咽喉头颈外科杂志

OBJECTIVE@#To analysis the acoustic characteristics in patients with unilateral arytenoid dislocation and unilateral vocal fold paralysis, and evaluate the application value of acoustic analysis technique in these two diseases.@*METHOD@#The voice signals of sustained vowel /a/ were measured using the software MDVP in 50 healthy adults and 67 patients with unilateral vocal cord movement disorders. The acoustic parameters (jitter, shimmer, NHR and F₀) were analyzed. All patients were divided into arytenoid dislocation group (36 cases) and vocal fold paralysis group (31 cases) through the laryngeal electromyography. All groups were divided into male and female group again. The acoustic characteristics between the two experimental groups and normal control groups were observed and compared. Results were analyzed using Rank sum test.@*RESULT@#(1) In both male or female groups, there were significant differences in jitter and shimmer between two experimental group and control group. In both male or female groups, there were significant differences in NHR between arytenoid dislocation group and control group. There were no significant differences in NHR between vocal fold paralysis group and control group. Except for the male vocal fold paralysis group, there were significant differences in F between the other experimental groups and control groups. (2) In both male or female groups, there were no significant differences in jitter and shimmer between vocal fold paralysis group and arytenoid dislocation group. There were significant differences in NHR.@*CONCLUSION@#The acoustic parameters are effective parameters to measure the voice quality of patients with unilateral arytenoid dislocation and unilateral vocal fold paralysis. NHR is the most sensitive parameter in the distinction of vocal cord paralysis and arytenoid dislocation.

Effect of 1α, 25-dihydroxyvitamin D3 on T helper cell 17 and expression of related cytokines in penetrating keratoplasty in mice / 中国病理生理杂志

[ ABSTRACT] AIM:To evaluate the effects of 1α, 25-dihydroxyvitamin D3 on T helper cell 17 ( Th17 cells) and its related cytokines in a mouse model of corneal allograft transplantation.METHODS:C57BL/6 mice were transplanted with corneal grafts from BALB/c mice and treated intraperitoneally with 1.0μg 1α, 25-dihydroxyvitamin D3 or soybean oil every other day after operation.The transparency of the corneal grafts was evaluated for potential rejection signs by slit lamp biomicroscopy and histopathology.The expression levels of IL-17, RORγt and IFN-γin the spleen were measured by real-time PCR.Moreover, the protein expression of RORγt and IL-17 in the peripheral blood was analyzed by Western blotting. IL-17 and IFN-γin peripheral blood were measured by flow cytometry.RESULTS:1α, 25-dihydroxyvitamin D3 signifi-cantly inhibited the rejection of the corneal allograft and reduced the numbers of inflammatory infiltrates in the corneal graft. In the spleen, 1α, 25-dihydroxyvitamin D3 treatment reduced the expression levels of IL-17, RORγt and IFN-γ.In the pe-ripheral blood, 1α, 25-dihydroxyvitamin D3 treatment downregulated the expression levels of RORγt, IL-17 and IFN-γ. CONCLUSION:The effects of 1α, 25-dihydroxyvitamin D3 on suppressing corneal transplantation-induced allograft rejec-tion in mice are closely associated with its modulation on IL-17 and related cytokine RORγt.

A Meta analysis of association between IL-1 gene polymorphisms and Beh(c)et disease susciptibility / 中华实验眼科杂志

Background Interleukin (IL)-1a-889C/T,IL-1β-S11C/T,+ 3962C/T and IL-1Ra-2 are different morphology of single nucleotide of interleuki-1 (IL-1).The potential relationship of IL-1 polymorphisms with Beh(c)et disease has been studied in several populations and groups.However,study outcomes are controversial for a long duration.Objective This Meta-analysis was to determine whether the IL-1 gene polymorphisms is associated with the pathogenesis and development of Beh(c)et disease.Methods The literature of the assoiation between IL-1 polymorphisms and Beh(c)et disease was retrieved from Medline,EMBASE,Cochrane Library,Web of knowledge,Google Scholar,Wanfang and CNKI databases.All the published original articles (case-control studies) were reviewed with the deadline May 31,2013,and the languages were limited to English and Chinese.Included reports were evaluated based on Newcastle-Ottawa Scale (NOS) score.The potential influence of IL-1α-889TT gene,IL-1β-3962C,IL-1β-511T and IL-1Ra-2 polymorphisms on Beh(c)et disease were analyzed.RevMan5.0,the Cochrane collaboration software program,was used to prepare and complete this review.The effect size was assessed using fixed effect model in the index with lower heterogeneity (I2 ＜50％) or randomized effect model in the index with higher heterogeneity (I2＞50％).Results The literature search resulted a total of 370 cases-controlled studies,and 7 studies met the included criteria,with the NOS scores ≥ 8.The total patients were 499 and normal controls were 708.Meta-analysis was performed on several populations.Overall,the polymorphisms of IL-1β-3962C allele increased the susciptibility of Beh(c)et disease (OR =1.41,95％ CI:1.06-1.88,P =0.02),and IL-1α-889TT genotype reduced the risk of Beh(c)et disease (OR =0.61,95 ％ CI:0.40-0.92,P =0.02).However,There was no significant association between variants of IL-1β-511T allele (OR =0.84,95％ CI:0.58-1.23,P=0.38) or IL-1RA-2 allele (OR =1.25,95％ CI:0.50-3.14,P=0.63) and Beh(c)et disease susciptibility.Conclusions These results suggest that Beh(c)et disease is associated with the IL-1 gene polymorphisms at the locations α-889C/T and β-3962C/T.A larger sample size clinical data still are need to confirm this conclusion.

Primary culture of corneal endothelial cells in vitro and biological identification / 中华实验眼科杂志

Background Corneal blindness is one of the major blinding eye diseases in China.With the development and progress of tissue engineering technology,tissue-engineered corneas offers a new approach to the treatment of corneal diseases.To select and cultivate ideal seed cells is a foundation of construction of tissueengineered corneas.Objective This study was to evaluate the efficiency of stripe off the Descemet membrane with endothelium plus enzymic digestion in the isolation of corneal endothelial cells and analyze the bionomics of rabbit corneal endothelial cells (CECs) in vitro.Methods Descemet membrane was stripped from fresh cornea of New Zealand rabbit under the dissection microscope.Descemet membrane with endothelium was incubated in trypsin and EDTA solution at 37 ℃ and then purified for CECs subculture in vitro.The morphology of the cultured cells was observed under the inverted microscope and marked by CM-Dil dye solution.Then the shape of the cells was observed by hematoxylin and eosin staining and the cells were identified for the expression of neuron specific enolase (NSE) using immunochemistry.The viability of the cells were evaluated by trypan blue staining.The surface structure of the cells were examined under the scanning electron microscope.Intercellular zonula occludens-1 (ZO-1) was identified by immunofluorecsence staining.Results A large number of purified CECs were obtained from Descemet membrane with endothelium through enzymic digestion.Cultured cells grew well and formed monolayer 5-7 days later with the cobblestone stone-like arrangement.The survival rate of the cells was 95％.CECs presented with the red annular fluorescence for CM-Dil with the labeling rate ＞90％.NSE was positively expressed in the cytoplasm.Polygon CECs were seen by hematoxylin and eosin staining and showed the brown staining.Abundant microvilli on the cellular surface and interconnected foot process were seen under the scanning electron microscope.ZO-1 showed the green fluorescence.Conclusions The method of striping off the corneal Descemet membrane with endothelium plus enzymic digestion can obtain abundant CECs.Cultured cells have good biological properties.This study may offer a feasible application in the engineering of corneal transplant membrane.

Effect and mechanisms of combined immunosuppressive agents sequential therapy in murine models of chronic graft-versus-host disease / 中华风湿病学杂志

ObjectiveTo explore the effects and possible mechanisms of VCR combined with low dose cyclophosphamide(CTX) intermittently to treat severe systemic lupus erythematosus(SLE).It is assumed that this might be a new combination therapy for SLE and expected to improve the overall prognosis and outcome of SLE.MethodsMurine chronic graft-versus-host disease(cGVHD) model were developed for study.They were randomly divided into the control group,vincristine (VCR) pulse therapy group,CTX pulse therapy group,CTX every other day(EOD) group,VCR+CTX combination group.One way ANOVA and repeated measure variance analysis were used for statistical analysis.Results① Six weeks after cGVHD models were set up,the average 24-hour urine protein quantification was(5.02±0.88) mg,anti-dsDNA antibody was positive,and Ⅳ LN pathology could be observed histologically in the model murine.So cGVHD models were successfully developed.② Significantly difference in decreasing of 24-hour urine protein quantification was found in the CTX EOD group,VCR+CTX combination group and other groups (P＜0.01).Significant decrease in Cr,ALT,anti-dsDNA,was found in the CTX EOD group,VCR+CTX combination group,CTX pulse therapy group and other groups(P＜0.05).Decrease in urine MCP-1 and TGF-β1 could be detected,and statistical significant difference in these parameters could be found in the CTX EOD group,CTX pulse therapy group,VCR+CTX combination group and other groups (P＜0.01).MCP-1 and TGF-β1'expression in model kidney were reduced in the CTX EOD group,VCR+CTX combination group and had statistical significant difference in the CTX EOD group,VCR+CTX combination group,VCR pulse therapy group,and CTX pulse therapy group.③ VCRand CTX combination treatment was effectivein 24-hour urine protein quantification,blood Cr,ALT,anti-dsDNA and urine MCP-1,as well as urine TGF-β1 (P＜0.05).Conclusion ① The combination of VCR and CTX is synergistic in decreasing 24-hour urine protein quantification,Cr,and the expression of MCP-1,TGF-β1.② The adverse effect of VCR+CTX combination group is similar to VCR pulse therapy group and CTX pulse therapy group.