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BACKGROUND/AIMS: Accumulating evidence strongly suggests that microRNAs (miRNAs) modulate the expression of known tumor suppressor genes and oncogenes. In the present study, we found that the proliferation and invasion ability of pancreatic ductal adenocarcinoma (PDAC) cells were significantly suppressed by the overexpression of miR-23b-3p. In addition, there are miR-23b-3p binding sites in annexin A2 (ANXA2). Here, we investigated whether miR-23b-3p had an impact on the progression and metastasis of PDAC by targeting ANXA2. METHODS: Cell proliferation, migration, and invasion, and cell cycle assays were performed to explore the effect of miR-23b-3p on various malignant phenotypes of pancreatic cancer cells. The size of tumors was observed following miR-23b-3p overexpression in an in vivo chick chorioallantoic membrane assay. Dual-luciferase reporter, quantitative real-time PCR, western blot, and immunohistochemical analyses were used to validate the relationship between miR-23b-3p and ANXA2 in vitro. RESULTS: We observed that miR-23b-3p could bind specifically to the 3' untranslated region of ANXA2 and inhibit its expression. MiR-23b-3p overexpression downregulated the expression of ANXA2 mRNA in PDAC cells and limited the size of tumors or even prevented tumor formation. In addition, there was a negative correlation between miR-23b-3p expression and ANXA2 protein expression in clinical specimens. CONCLUSION: MiR-23b-3p inhibits the development and progression of PDAC by regulating ANXA2 directly.
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Anexina A2/metabolismo , Carcinoma Ductal Pancreático/patologia , MicroRNAs/metabolismo , Neoplasias Pancreáticas/patologia , Regiões 3' não Traduzidas , Adulto , Animais , Anexina A2/genética , Antagomirs/metabolismo , Sequência de Bases , Carcinoma Ductal Pancreático/metabolismo , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Galinhas , Membrana Corioalantoide/irrigação sanguínea , Membrana Corioalantoide/patologia , Feminino , Humanos , Masculino , MicroRNAs/antagonistas & inibidores , MicroRNAs/genética , Pessoa de Meia-Idade , Neovascularização Patológica/patologia , Neoplasias Pancreáticas/metabolismo , Alinhamento de SequênciaRESUMO
The advancement of metabolic engineering and synthetic biology has promoted in-depth research on the nonmodel microbial metabolism, and the potential of nonmodel organisms in industrial biotechnology is becoming increasingly evident. The nonmodel organism Pseudomonas chlororaphis is a safe plant growth promoting bacterium for the production of phenazine compounds; however, its application is seriously hindered due to the lack of an effective gene expression precise regulation toolkit. In this study, we constructed a library of 108 promoter-5'-UTR (PUTR) and characterized them through fluorescent protein detection. Then, 6 PUTRs with stable low, intermediate, and high intensities were further characterized by report genes lacZ encoding ß-galactosidase from Escherichia coli K12 and phzO encoding PCA monooxygenase from P. chlororaphis GP72 and thus developed as a static gene expression regulation system. Furthermore, the stable and high-intensity expressed PMOK_RS0128085UTR was fused with the LacO operator to construct an IPTG-induced plasmid, and a self-induced plasmid was constructed employing the high-intensity PMOK_RS0116635UTR regulated by cell density, resulting in a dynamic gene expression regulation system. In summary, this study established two sets of static and dynamic regulatory systems for P. chlororaphis, providing an effective toolkit for fine-tuning gene expression and reprograming the metabolism flux.
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Pseudomonas chlororaphis , Pseudomonas chlororaphis/genética , Pseudomonas chlororaphis/metabolismo , Engenharia Metabólica/métodos , Regulação Bacteriana da Expressão Gênica/genética , Regiões Promotoras Genéticas/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismoRESUMO
AIM:To explore the use of attention mechanism and Pix2Pix generative adversarial network to predict the postoperative corneal topography of age-related cataract patients undergone femtosecond laser arcuate keratotomy.METHODS:In this retrospective case series study, the 210 preoperative and postoperative corneal topographies from 87 age-related cataract patients(105 eyes)undergoing femtosecond laser arcuate keratotomy at Shanxi Eye Hospital between March 2018 and March 2020 were selected and divided into a training set(180)and a test set(30)for model training and testing. The peak signal-to-noise ratio(PSNR), structural similarity(SSIM)and Alpins astigmatism vector analysis were used to compare the accuracy of postoperative corneal topography prediction under different attention mechanisms.RESULTS:The model based on attention mechanism and Pix2Pix network can predict postoperative corneal topography, among which the model based on Self-Attention mechanism has the best prediction effect, with PSNR and SSIM reaching 16.048 and 0.7661, respectively. There were no statistically significant differences in the difference vector, difference vector axis position, surgically induced astigmatism, and correction index between real and generated corneal topography on the 3mm and 5mm rings(all P>0.05).CONCLUSION:Based on the Self-Attention mechanism and Pix2Pix network, the postoperative corneal topography can be well predicted, which can provide reference for the surgical planning and postoperative effects of ophthalmic clinicians.
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Objective To investigate the status of suicidal behaviors and suicidal ideation among HIV positive patients in Guangzhou, and to explore its relevant psycho-social factors. Methods We conducted a cross-sectional survey of HIV positive adult patients in six districts of Guangzhou to collect social-demographic characteristics, HIV infection time, suicidal ideation, suicidal behaviors and psycho-social factors. Use suicidal ideation and suicidal behaviors as the dependent variables to conduct the univariate analysis and multivariate Logistic regression analysis. Results Of the 464 subjects,5.2% and 17.4% of them had suicidal behaviors and suicidal ideation. Analysis showed that the infection route, depression, anxiety, social discrimination, self-discrimination were correlated with the suicidal behaviors(all P<0.05), while age, health status, spouse infection, depression, anxiety and social support, social discrimination, self-discrimination were correlated with the suicidal ideation(all P<0.05). Multivariate Logistic regression model showed that depression and self-discrimination were associated with suicidal behaviors(all P<0.05),depression and social discrimination were associated with suicidal ideation (all P<0.05). Conclusions HIV-positive adult patients in Guangzhou have a high incidence of suicidal ideation and behaviors. Psychological counseling, risk assessment and timely treatment related to depression, social discrimination self-discrimination and early antiviral treatment should be targeted in HIV-positive adult patients.
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BACKGROUND: Due to its strong catalytic activity and selective catalytic oxidation, gold-silver bimetallic nanoparticles have potential applications in biomedicine, drug delivery and electrochemical analysis.OBJECTIVE: To prepare the gold-silver alloy nanoparticles using mitochondria in animal cells as templates. METHODS: Separating mitochondria from the fish liver: 1 mL of mitochondrial mother liquor was added into 1 mL of alkaline HAuCl4solution (10 mmol/L) and shaken; then, 1 mL of AgNO3solution (10 mmol/L) was added, and the mixture was reacted in an electromagnetic stirrer for 20-30 hours until the color of the reaction solution was changed from colorless to purple, which indicated that gold and silver alloy nanoparticles were successfully obtained; finally, the characterization of the nanoparticles was analyzed. (1) Cytotoxicity test: gold-silver alloy nanoparticles atdifferent concentrations (0, 25, 50, 75, 100, 125, 150 mg/L) were added into gastric cancer cells. After 48 hours of culture, the proliferation of cells (absorbance value) was detected by MTT assay. (2) Stability evaluation: 1 mL of gold-silver alloy nanoparticles at different concentrations (0, 25, 50, 75, 100, 125, 150 mg/L) were placed into glass reaction flasks and then, 0.2 mL of ultrapure water was added in portions following by shaking. After addition of the ultra-pure water, ultraviolet-visible spectrum was used to analyze the characterization of the solution. RESULTS AND CONCLUSION: The gold-silver alloy nanoparticles were spherically distributed and confirmed to have an alloy structure with the average particle size of 20-30 nm, and presented to have the advantages of simple structure, good crystallinity, and active groups such as hydroxyl and carbonyl groups on the surface. MTT results showed that the gold-silver alloy nanoparticles at the mass concentration of < 150 mg/L had no obvious cytotoxicity. The characteristic absorption peak with the largest intensity was positively correlated with the concentration of gold-silver alloy nanoparticles.To conclude,the gold-silver alloy nanoparticles have good cytocompatibility and stability in vitro.
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BACKGROUND:The extraocular muscles control the movement of the eyeball,and its biomechanics is essential for studying eye movement.OBJECTIVE:To determine the differences in mechanical properties of the extraocular muscles in different mammals.METHODS:This was an in vitro study.The extraocular muscles were extracted from foxes,pigs and sheep,and then we used an Instron 5544 tester to perform uniaxial experiments under the same load.Ogden hyperelastic models of each animal extraocular muscle were obtained based on the experimental data,and the passive mechanical behaviors of the extraocular muscle were compared statistically among different animals.RESULTS AND CONCLUSION:The order of load-strain values was as follows:fox > sheep > pig.The fitted curve of each animal extraocular muscle was well in accordance with the mean data.There were significant differences in the passive mechanical behaviors of extraocular muscles among mammals,including hyperelastic parameters and stress response at the same load level.
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Objective To perform finite element analysis on a type of newly designed total knee prosthesis,and investigate the influence from changing twist angle of the lateral condyle surface on mechanical environment of the knee joint.Metheds Based on CT measurement data from a volunteer,3 artificial knee prostheses with the same medial condyle were established.In Model 1,the twist angle of lateral condyle surface was 0°,while 10° and 20° in Model 2 and Model 3,respectively.The prosthesis models were imported into finite element software and applied with gait cycle data to simulate the motion of knee prosthesis during the gait cycle.The simulated stress results in the knee joint were then compared with the calculated results,which were obtained from theoretical formula of contact mechanics.Results The maximum stress of 3 models appeared at 13% of the gait cycle,when the axial force (2.6 kN) was also the maximum.The maximum stresses of medial and lateral condyle in Model 1,Model 2 and Model 3 were 35.5 and 30.6 MPa,38.4 and 32.6 MPa,38.3 and 43.1 MPa,respectively.The stress curves of Model 2 and Model 3 during the gait cycle were relatively smooth compared with those of Model 1.The simulated stress trend was basically similar to the theoretical calculation,except at a few moments in the gait cycle.Conclusions The mechanical environment of the total knee prosthesis can be improved by twist angle of the lateral condyle surface.This newly designed prosthesis can preserve implants from abrupt change of the stress during the gait cycle and prolong the service life of prostheses.
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Objective To determine the hyperelastic parameters of shear modulus (μ) and curvature parameter (α) of extraocular muscles (EOMs) in Ogden hyperelastic model,so as to provide theoretical basis for clinical EOM surgery by numerical modeling.Methods The passive behavior of fox EOMs in vitro was determined by the uniaxial tensile test,and the hyperelastic analysis was conducted using the first-order Ogden model and ABAQUS software.Results The experimental result showed that the passive behavior of fox EOMs was nonlinear.The corresponding hyperelastic parameters μ =(6.57 ± 3.76) kPa and oα =8.16 ± 1.63 were obtained.When the strain of EOMs was larger than 6%,there were no statistical differences between the experimental result and the calculation result of the first-order Ogden hyperelastic model (P > 0.05).Both the calculation result and the simulation result well fitted to the experimental result.Conclusions The hyperelastic parameters identified in this study can be used as the input for the corresponding numerical modeling of fox EOMs.
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Objective To determine the hyperelastic parameters of shear modulus (μ) and curvature parameter (α) of extraocular muscles (EOMs) in Ogden hyperelastic model,so as to provide theoretical basis for clinical EOM surgery by numerical modeling.Methods The passive behavior of fox EOMs in vitro was determined by the uniaxial tensile test,and the hyperelastic analysis was conducted using the first-order Ogden model and ABAQUS software.Results The experimental result showed that the passive behavior of fox EOMs was nonlinear.The corresponding hyperelastic parameters μ =(6.57 ± 3.76) kPa and oα =8.16 ± 1.63 were obtained.When the strain of EOMs was larger than 6%,there were no statistical differences between the experimental result and the calculation result of the first-order Ogden hyperelastic model (P > 0.05).Both the calculation result and the simulation result well fitted to the experimental result.Conclusions The hyperelastic parameters identified in this study can be used as the input for the corresponding numerical modeling of fox EOMs.
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Objective To determine the hyperelastic parameters shear modulus (μ) and curvature parameter (α) of extraocular muscles (EOMs) in Ogden hyperelastic model, so as to provide theoretical basis for clinical EOM surgery by numerical modeling. Methods The passive behavior of fox EOMs in vitro was determined by the uniaxial tensile test, and the hyperelastic analysis was conducted by the first-order Ogden model and ABAQUS software. Results The experimental result showed that the passive behavior of fox EOMs was nonlinear. The corresponding hyperelastic parameters μ =(6.57±3.76) kPa and α=8.16±1.63 were obtained. When the strain of EOMs was larger than 6%, there were no statistical differences between the experimental result and the calculation result of the first-order Ogden hyperelastic model (P>0.05). Both the calculation result and the simulation result well fitted to the experimental result. Conclusions The hyperelastic parameters identified in this study can be used as the input for the corresponding numerical modeling of fox EOMs.
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Objective To perform finite element analysis on a type of newly designed total knee prosthesis, and investigate the influence from changing twist angle of the lateral condyle surface on mechanical environment of the knee joint. Methods Based on CT measurement data from a volunteer, 3 artificial knee prostheses with the same medial condyle were established. In Model 1, the twist angle of lateral condyle surface was 0°, while 10° and 20° in Model 2 and Model 3, respectively. The prosthesis models were imported into finite element software and applied with gait cycle data to simulate the motion of knee prosthesis during the gait cycle. The simulated stress results in the knee joint were then compared with the calculated results, which were obtained from theoretical formula of contact mechanics. Results The maximum stress of 3 models appeared at 13% of the gait cycle, when the axial force (2.6 kN) was also the maximum. The maximum stresses of medial and lateral condyle in Model 1, Model 2 and Model 3 were 35.5 and 30.6 MPa, 38.4 and 32.6 MPa, 38.3 and 43.1 MPa, respectively. The stress curves of Model 2 and Model 3 during the gait cycle were relatively smooth compared with those of Model 1. The simulated stress trend was basically similar to the theoretical calculation, except at a few moments in the gait cycle. Conclusions The mechanical environment of the total knee prosthesis can be improved by twist angle of the lateral condyle surface. This newly designed prosthesis can preserve implants from abrupt change of the stress during the gait cycle and prolong the service life of prostheses.
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Ocular biomechanics are generally applied in the diagnosis treatment of high myopia and ocular movement disorder. Progress has also achieved in the development of glaucoma and ocular trauma research fields. In this paper, the advances in the modeling of eye movement, the mechanical properties and mechanobiology of the cornea and sclera, glaucoma biomechanics, and the mechanism of ocular trauma are reviewed.
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Objective To study the biomechanical effect from pulley tissues of extraocular muscles on super adduction of the eye. Methods By the coordinate parameters of extraocular muscles reported in the literature and based on the mechanical equilibrium of eye movement, two mechanical models, active pulley model and non pulley model (as control), were established to simulate eye adduction in the range of 30°-45°. Results For the contribution of medial rectus muscle, the non pulley model produced more force than the active pulley model to control eye adduction, and its corresponding force value increasingly exceeded the physiologically safe threshold (0.5 N). At the maximum simulative adduction of 45°, the force of medial rectus obtained by active pulley model and non pulley model was 0.508 N and 0.782 N, respectively, and the latter was 56% greater than the safe threshold. For controlling eye adduction, the active pulley model consumed much less energy than the non pulley model. Conclusions Due to the existence of pulley tissues, extraocular muscles could control eye adduction by consuming less biological energy and reinforce the ocular derivation. In addition, with the active pulley, the medial rectus muscle could maintain its mechanical advantage under super adduction of the eye.
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Objective To explore the combined effects of mechanical stretch and interleukin-1β (IL-1β) on gene expression of extracellular matrix in rabbit corneal fibroblasts. Methods Isolated rabbit corneal fibroblasts were subjected to 15% equibiaxial stretch at frequency of 0.1 Hz for 12 h, 24 h and 36 h, respectively, in presence of IL-1β. The gene expressions of matrix metalloproteinases (MMPs), tissue inhibitor of metalloproteinases 1 (TIMP-1) and collagen type I alpha 1 (Collagen Iα1) were detected by real-time quantitative PCR. Results The mRNA levels of MMP-1, MMP-3 and MMP-9 could be up-regulated by IL-1β alone. However, MMP-1 and MMP-3 mRNA levels decreased with time, while MMP-9, TIMP-1 and collagen Iα1 increased with time. Compared with corresponding IL-1β treatment with mechanical stretch groups, the mRNA levels of MMP-1, MMP-3 and MMP-9 were increased and the mRNA levels of TIMP-1 and collagen Iα1 were decreased in a time-dependent manner. The mRNA level of Collagen Iα1 was decreased by loading mechanical stretch alone, and would further decrease time-dependently in combination with IL-1β treatment. Conclusions Mechanical stretch combined with IL-1β may facilitate the corneal tissue damage, thereby contribute to the development of keratectasia.
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Objective To investigate the effect of different mechanical environment ( in vivo and in vitro) on expression of basic fibroblast growth factor (bFGF) and explore the role of mechanical stimulation in corneal tissue repair after laser assisted in situ keratomileusis (LASIK) surgery. Methods Animal models by LASIK surgery were established to keep the corneas under different mechanical environment. The experimental animals were killed at the first week or the first month after LASIK surgery to obtain the corneas. In addition, the primary corneal fibroblasts were subjected to cyclic mechanical stretch (0.1 Hz; 5%, 10%, 15% stretch; 6 h or 24 h) using Flexcell 4 000 tension system. Expression of bFGF was determined by ELISA method. Results At the first week after LASIK surgery, expression of bFGF was increased significantly in 30% group (residual stroma bed accounting for 30% of the whole cornea), as compared with the control group (P<0.05), and then it was decreased to the normal level in all groups at the first month after LASIK surgery. Analysis on the same surgery method at different time showed that there were significant differences only in 30% group at the first week and month (P<0.05). Cyclic stretch experiment in vitro indicated that bFGF expression in 15% stretch group was significantly increased after 6 h than that in the control group (P<0.05), with a significant decrease after 24 h (P<0.05). Conclusions Mechanical stimulation can regulate bFGF expression of corneal tissues and corneal frbroblasts, and bFGF plays a positive role in the early corneal tissue repair after LASIK surgery.
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<p><b>BACKGROUND</b>The mechanical microenvironment of the chondrocytes plays an important role in cartilage homeostasis and in the health of the joint. The pericellular matrix, cellular membrane of the chondrocytes, and their cytoskeletal structures are key elements in the mechanical environment. The aims of this study are to measure the viscoelastic properties of isolated chondrons and chondrocytes from rabbit knee cartilage using micropipette aspiration and to determine the effect of aging on these properties.</p><p><b>METHODS</b>Three age groups of rabbit knees were evaluated: (1) young (2 months, n = 10); (2) adult (8 months, n = 10); and (3) old (31 months, n = 10). Chondrocytes were isolated from the right knee cartilage and chondrons were isolated from left knees using enzymatic methods. Micropipette aspiration combined with a standard linear viscoelastic solid model was used to quantify changes in the viscoelastic properties of chondrons and chondrocytes within 2 hours of isolation. The morphology and structure of isolated chondrons were evaluated by optical microscope using hematoxylin and eosin staining and collagen-6 immunofluorescence staining.</p><p><b>RESULTS</b>In response to an applied constant 0.3 - 0.4 kPa of negative pressure, all chondrocytes exhibited standard linear viscoelastic solid properties. Model predictions of the creep data showed that the average equilibrium modulus (E(∞)), instantaneous modulus (E(0)), and apparent viscosity (m) of old chondrocytes was significantly lower than the young and adult chondrocytes (P < 0.001); however, no difference was found between young and adult chondrocytes (P > 0.05). The adult and old chondrons generally possessed a thicker pericellular matrix (PCM) with more enclosed cells. The young and adult chondrons exhibited the same viscoelastic creep behavior under a greater applied pressure (1.0 - 1.1 kPa) without the deformation seen in the old chondrons. The viscoelastic properties (E(∞), E(0), and m) of young and adult chondrons were significantly greater than that observed in young and adult cells, respectively (P < 0.001). The adult chondrons were stiffer than the young chondrons under micropipette aspiration (P < 0.001).</p><p><b>CONCLUSIONS</b>Our findings provide a theoretical model to measure the viscoelastic properties of the chondrons as a whole unit by micropipette aspiration, and further suggest that the properties of the chondrocytes and PCM have an important influence on the biomechanical microenvironment of the knee joint cartilage degeneration that occurs with aging.</p>
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Animais , Coelhos , Envelhecimento , Fisiologia , Cartilagem Articular , Metabolismo , Condrócitos , Metabolismo , Elasticidade , ViscosidadeRESUMO
Background There have been an abundance of literature on the analysis of the mechanical characteristic of the sclera at the entire seleral level in high myopia.However,some recent studies on high myopia are focused on the mechanical changes of the sclera on a cellular level. Objective This experiment was purposed to study how transforming growth factor-β2(TGF-β2)affected sclerotic desmocytes and the mechanical behaviors of scleral fibroblasts in the posterior part of the eyes in guinea pigs with experimental myopia. Methods Induced myopic animal models were established by wearing-10.00 D concave lens for 30 days in lateral eyes of 2-week-old guinea pigs.The fellow eyes were used as control group.Another 5 matched animals served as normal controls.The scleral fibroblasts of each group were purified with the tissue explant method and passaged for 2 generations in vitro.Cultured cells were identified by immunochemistry with vimentin,desmin,keratin and S-100 antibodies.Different concentrations of TGF-β2(0,1,10,100mg/L)were added into serum-free DMEM for 24 hours,and the viscoelastic properties of scleral fibroblasts were measured by micropipette aspiration technique. Results Compared with the fellow,eyes and normal control eyes,the equilibrium modulus and apparent viscosity in model eyes were significantly higher(P<0.05).After treatment of TGF-β2,the equilibrium modulus and apparent viscosity in the model group and fellow eyes were positively correlated with the concentrations of TGF-β2(r=0.743,r=0.533,r=0.654,r=0.576,P<0.05).Following the addition of 1 mg/L TGF-β2 and 10 mg/L TGF-β2,the equilibrium modulus and apparent viscosity of scleral fibroblasts were significantly reduced in model eyes compared with fellow eyes(P<0.05).No significant difference was found in the equilibrium modulus and apparent viscosity of scleral fibroblasts between model eyes and fellow eyes after treatment with 100 mg/L TGF-β2(P>0.05). Conclusion TGF-β2 car increase the mechanic indexes in a concentration.dependent manner.1 mg/L,10 mg/L TGF-β2 can lower the equilibrium modulus and apparent viscosity of scleral fibroblasts of normal eye and thus cause more changes in the mechanical behavior of scleral fibroblasts.
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Sclera plays an very important role in maintenance of eyeball structure and its functions. The biological and biomechanical properties of sclera is determined by the extra cellular matrix metabolism, the cytokine expression and its own biomechanical properties of scleral fibroblasts. Lots of biological and biomechanical changes in sclera and scleral fibroblasts are the concomitants in the process of myopic development and therapy. The biomechanical studies on sclera and scleral fibroblasts by Mechanics Biology coupling will enable to reveal the physiological function, pathological change and therapeutic mechanism of ocular organ and in this review, such biomechanical studies about sclera and scleral fibroblasts were summarized and discussed.
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Objective To evaluate the biomechanical properties of fibroblasts for rabbit experimental myopia after Posterior Scleral Reinforcement (PSR) treatment, and discuss the mechanism of PSR in myopia treatment as viewed from biomechanics. Method 45 rabbits of three week old were randomly monocular treated by eyelid suture to prepare experimental myopia eye. After 60 days, the experimental myopia eyes were divided into two groups randomly. Group A was treated by PSR. Group B was treated by similar operation without placing reinforce strap. After three months and six month, the fibroblasts from each group were isolated and cultured in vitro respectively. The cultured cells were then determined to be fibroblasts by using immunocyte chemistry method. Micropipette aspiration technique was used to investigate the viscoelastic properties of the fibroblasts from each group with mechanical model of semi infinite somatic cells. ResultsThree months after operation, the viscoelastic properties of the scleral fibroblasts in Group A and Group B exhibit no significant difference (P>0.05) three months and six months as well (P>0.05) after operation with the equilibrium modulus, E∞, and apparent viscosity, μ of the scleral fibroblasts in Group A (E = (361.2± 121.1)Pa、μ=(2928.2±669.4)Pa·s) compared with that in Group B (E =(347.6± 82.1)Pa、μ=(2820.6± 593.5)Pa·s). Neither in Group A nor Group B, the E∞ and μ at different stages after operation have significant difference (P>0.05). The E∞ and μ in transition zone tissues at different stages after operation have no significant difference(P>0.05) either. Conclusions The enhancement of PSR is caused by transition zone tissues and the strip itself.
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<p><b>OBJECTIVE</b>To assess the biomechanical stability of asymmetrical posterior internal fixation for transforaminal lumbar interbody fusion (TLIF) with transfacetopedicular screws (TFPS).</p><p><b>METHODS</b>Range of motion (ROM) testing was performed in 7 fresh-frozen human cadaveric lumbar spine motion segments in flexion/extension, lateral bending, and axial rotation using 10.0 Nm torques at the L3-4 motion segment. The sequential test configurations included intact motion segment, TLIF and ipsilateral pedicle screw (PS), TLIF and ipsilateral PS plus contralateral TFPS according to Boucher technique, and TLIF and bilateral PS. The ROM was determined to assess the construct stability.</p><p><b>RESULTS</b>In flexion/extension, lateral bending, and axial rotation, no measureable difference was found in the ROM between the standard bilateral pedicle screw and the novel asymmetric posterior internal fixation after TLIF. After TLIF, the ipsilateral PS construct provided less segment stability than the novel asymmetric construct with TFPS in flexion, left bending and left rotation. In rotation, the novel asymmetric construct allowed for significant off-axial rotation motions detrimental to the stability and fusion.</p><p><b>CONCLUSION</b>Ipsilateral PS placement plus contralateral TFPS provides stability comparable to that of TLIF with bilateral PS, and can be an alternative in minimal invasive surgery.</p>