Percutaneous vertebroplasty in treatment of osteoporotic vertebral compression fracture by two different approaches: Bone cement leakage and safety北大核心

BACKGROUND: Clinical therapies of osteoporotic vertebral compression fracture have two different approaches, including unilateral pedicle extrapedicle and bilateral pedicle approach of percutaneous vertebroplasty, but there were fewer reports about postoperative bone cement leakage rate and security in the two approaches. OBJECTIVE: To compare postoperative bone cement leakage rate and security with osteoporotic vertebral compression fracture by two different approaches, unilateral pedicle extrapedicle and bilateral pedicle approach of percutaneous vertebroplasty. METHODS: This study enrolled 60 cases with the osteoporotic vertebral compression fracture who were patients meeting the inclusion criteria in the First Affiliated Hospital of Hebei North University from January 2018 to December 2020. The 60 cases were randomly divided into two groups according to surgical approach. Group A (n=30) was treated with unilateral pedicle extrapedicle approach of percutaneous vertebroplasty. Group B (n=30) was treated with bilateral pedicle approach of percutaneous vertebroplasty. The volume of bone cement injection, bone cement leakage rate and other complications, as well as kyphosis angle of the compressive vertebral body, the visual analogue scale score, and Oswestry disability index were compared between the two groups. RESULTS AND CONCLUSION: (1) There was no statistical significance in the volume and leakage rate of bone cement injection in two groups (P > 0.05). (2) Visual analogue scale score and Oswestry disability index were significantly lower at 1, 3 days, and 1 month after surgery compared with that preoperatively in both groups (P < 0.05). Postoperative kyphosis angle of the compressive vertebral body was less than that preoperatively (P < 0.05). There was no statistical difference in visual analogue scale score, Oswestry disability index, and kyphosis angle at various time points after surgery in both groups (P > 0.05). (3) The results suggest that satisfactory clinical effect can be obtained by two different approaches, unilateral pedicle extrapedicle and bilateral pedicle approach of percutaneous vertebroplasty. © 2022, Publishing House of Chinese Journal of Tissue Engineering Research. All rights reserved.     

Design and biomechanical properties of dental implant pore structure based on three-dimensional finite element analysis北大核心

BACKGROUND: Studies have shown that the elastic modulus can be changed by changing the pore internal unit structure when designing porous implants, providing a new way to better balance implant strength and elastic modulus. OBJECTIVE: To analyze dental implant biomechanical properties with different micro pore structures by finite element analysis so as to elucidate the effects of different micro pore structures on the surrounding bone stress and implant physical properties. METHODS: A mandibular model and three finite element models of dental implants with different pore structures (conventional structural pores, composite structural pores, and G7 structural pores) were built by CT scanning with porosity of 40%, the thickness of the porous layer of 1.2 mm, and the pore size of 0.45 mm. The ultimate force state was simulated to apply load to each model, which was operated by ANSYS finite element software and analyzed by surrounding bone stress and strain of the implants. RESULTS AND CONCLUSION: (1) When implants were subjected to the ultimate force, the maximum values of effector forces such as 38.324, 56.574, 64.694 MPa for conventional structure, composite structure and G7 structure dental implants on the surrounding cortical bone were respectively 1.836, 10.221, 9.439 MPa, and the maximum values of effector forces such as implants were 156.38, 476.23, 457.76 MPa. The maximum surrounding bone stress of the composite structure implant was within the range of promoting osseointegration. (2) When only lateral forces were applied to the implants, the maximum strain values of dental implants placed in the conventional structure, composite structure and G7 structure were 2.222 9×10-2, 1.661 9×10-2, 3.210 9×10-2 mm/mm. When only axial forces were applied to the implants, the maximum strain values of dental implants placed in the conventional structure, composite structure and G7 structure were 2.266 2×10-3, 1.844 6×10-3, 2.971 5×10-3 mm/mm, indicating that when subjected to lateral static load and axial load, the strain of the composite structure implant was smallest and the micro-movement was small, which helped to improve the osseointegration effect. (3) The results showed that the surrounding bone stress changed significantly with the change of pore unit cell structure inside the porous implant, and the mechanical properties of the implant also changed, and the change of unit cell structure shape of the porous structure on the implant surface significantly affected the elastic modulus and the mechanical properties of the implant. Dental implants with a composite pore structure had better biomechanical properties compared with conventional constructs and G7 constructs. © 2022, Publishing House of Chinese Journal of Tissue Engineering Research. All rights reserved.     

Influence of arch curvature and all-ceramic materials on fatigue life of fixed bridges: A finite element analysis北大核心

BACKGROUND: The cyclic fatigue finite element method is more useful to study the fatigue life of the prosthesis in accordance with the actual situation of the oral cavity. OBJECTIVE: To study the all-ceramic fixed bridge fatigue life with different arch curvatures and materials. METHODS: According to the arch curvature, four sets of models (group I, 0°; group II, 30°; group III, 60°; group IV, 90°) were set up on the basis of a digital model of all-ceramic fixed bridge. Fatigue life of each model was analyzed with different materials (In-Ceram Zirconia, Zenotec, LAVA). RESULTS AND CONCLUSION: The stress was mostly concentrated at the join of the all-ceramic fixed bridge. It was also the most part of the stress extremum, the shortest part of fatigue life and the most easily damaged part of the material. With the increase of arch curvature, the fatigue life of Group In-Ceram Zirconia dropped from 4.6 to 1.7 years, while both Group Zenotec and Group LAVA had the fatigue life of 19.6 years. The part of minimum life was the join of the fixed bridge. These findings indicate that the expected fatigue life of In-Ceram Zirconia all-ceramic fixed bridge restoration is relatively short, which may be an inappropriate repair material in anterior and posterior positions of canine teeth. All-ceramic materials, Zenotec and Lava, can meet the clinical life expectancy under different curvatures. © 2018, Journal of Clinical Rehabilitative Tissue Engineering Research. All rights reserved.     

Effects of internal stress concentrations in plantar soft-tissue—A preliminary three-dimensional finite element analysis

It has been hypothesized that diabetic foot ulceration might be internally initiated. This study established a three-dimensional and nonlinear finite element model of a human foot complex with comprehensive skeletal and soft-tissue components. The model was validated by experimental data of subject-specific barefoot plantar pressure measurements. The feasibility of the model to predict the 3D, internal, plantar soft-tissue deformation and stress was evaluated. The preliminary results indicate that large von Mises stress occurs where plantar soft-tissue contacts with geometrically irregular bony structures, thus internal stress distribution within the plantar soft-tissue was dramatically influenced by bony prominences due to stress concentration. At the forefoot part, an average stress magnification factor of 3.01 was quantified. The lateral sesamoid bone associated to the 1st MTH showed the largest effect of stress concentration. The modeling approach presented provides a possible way to explore the complexity of the mechanical environment inside the plantar soft-tissue.     

Biomechanical consideration of total hip arthroplasty following failed fixation of femoral intertrochanteric fractures – A finite element analysis

ObjectiveThe current study aimed to perform a biomechanical analysis of the effect and distribution of stress and strain values in the femur and its residual screw holes from the implantation of different lengths of total hip prostheses following failed dynamic hip screw (DHS) fixation of AO type A1.1 and A1.3 intertrochanteric fractures.MethodsMedical image processing, computer-assisted engineering design, and finite element analysis were combined for the analysis and the reliability of the model confirmed by convergence testing and comparison with a physical model. Using finite element analysis, patterns of stress from implantation of total hip prostheses with different stem length were obtained.ResultsStress distribution was concentrated over the third and fourth residual screw holes, especially in the models with shorter stem length. Fracture type (AO type A1.1 or A1.3) did not alter its distribution. In proximal cancellous bone, a stress-shielding effect was seen at the region of the residual fracture fragment, especially in the A1.1 fracture. In the fracture fixed with 2 cable wires, the maximum von Mises stress was in the proximal cable wire.ConclusionThe results suggest that an increase in the original stem length equal to the diameter of the femoral isthmus, or a distance between the most distal residual screw hole and the end of the femoral prosthesis, provide improved stress distribution.     

Biomechanical evaluation of two commonly used external fixators in the treatment of open subtalar dislocation—A finite element analysis

Subtalar dislocation is a rare injury caused by high-energy trauma. Current treatment strategies include leg casts, internal fixation and external fixation. Among these, external fixators are the most commonly used as this method is believed to provide better stabilization. However, the biomechanical stability provided by these fixators has not been demonstrated. This biomechanical study compares two commonly used external fixators, i.e. Mitkovic and Delta. CT imaging data were used to reconstruct three-dimensional models of the tibia, fibula, talus, calcaneus, navicular, cuboid, three cuneiforms and five metatarsal bones. The 3D models of the bones and cartilages were then converted into four-noded linear tetrahedral elements, whilst the ligaments were modelled with linear spring elements. Bones and cartilage were idealized as homogeneous, isotropic and linear. To simulate loading during walking, axial loading (70 N during the swing and 350 N during the stance phase) was applied at the end of diaphyseal tibia. The results demonstrate that the Mitkovic fixator produced greater displacement (peak 3.0 mm and 15.6 mm) compared to the Delta fixator (peak 0.8 mm and 3.9 mm), in both the swing and stance phase, respectively. This study demonstrates that the Delta external fixator provides superior stability over the Mitkovic fixator. The Delta fixator may be more effective in treating subtalar dislocation.     

How does the inclination of the tibial component matter? A three-dimensional finite element analysis of medial mobile-bearing unicompartmental arthroplasty

Background

Medial unicompartmental knee arthroplasty (UKA) using Oxford mobile-bearing prosthesis is performed in the treatment of medial compartmental arthritis of the knee. However, little is known about the stress distributions for mobile-bearing UKA on the medial tibial plateau.

Stem cells combined with three-dimensional scaffolds for the treatment of osteoporotic bone defects北大核心

BACKGROUND: Stem cells combined with a three-dimensional scaffold have great potential for the treatment of osteoporotic bone defects. OBJECTIVE: To introduce the application of stem cells combined with the three-dimensional scaffold in repairing osteoporotic bone defects. METHODS: A computer-based search of PubMed, Web of Science, Springerlink, Medline, WanFang and CNKI databases was performed for relevant articles published from 2007 to 2017 with “stem cells, scaffold, osteoporosis, bone defects” as key words in English and Chinese, repsectively. Initially, 142 articles were retrieved, and finally 45 articles were included in result analysis. RESULTS AND CONCLUSION: Due to the potential of self-renewal and multilineage differentiation, stem cells can be used to repair or regenerate damaged tissues, which are considered as an ideal cell source for the treatment of diseases in orthopedics. The suitable scaffold can provide a favorable microenvironment for repairing the attachment and growth of the cells related to the bone defect, which can promote the healing without additional side effects. Furthermore, stem cells combined with three-dimensional scaffolds provide a promising clinical application for the treatment of osteoporotic bone defects by regulation of bone metabolism. In addition, gene-modified stem cells with three-dimensional scaffolds bring a huge potential in the treatment of osteoporotic bone defects. In conclusion, the combination of stem cells and three-dimensional scaffolds provides a new approach for the treatment of osteoporotic bone defects, which may be one of the future therapeutic strategies. © 2018, Journal of Clinical Rehabilitative Tissue Engineering Research. All rights reserved.     

Biomechanical analysis of femoral neck system in unstable femoral neck fractures北大核心

BACKGROUND: The femoral neck system is a novel fixation device for unstable femoral neck fractures. OBJECTIVE: To compare and analyze the mechanical stability of three kinds of internal fixation in Pauwels III unstable femoral neck fractures by finite element method. METHODS: On the basis of the validated femoral finite element model (intact group), the model was cut to make a Pauwels III 70° unstable fracture of the femoral neck. Different internal fixation models were implanted to simulate clinical surgery. This study established femoral neck system fixation (model A), inverted triangular cannulated screw fixation (model B) and 4 diamond-shaped cannulated screw fixation (model C). All the nodes under the distal end of the femur were restrained for the three groups of models, and 700 N, 1 400 N and 2 100 N compressive loads were applied to the femoral head. Through calculation and analysis, the Von Mises stress distribution and deformation of each group of models were observed, and the mechanical stability of each group of models was compared. RESULTS AND CONCLUSION: (1) The maximum deformation of the three groups of models under various loads occurred in the femoral head. When compressed for 2 100 N, the deformation of model A was 2.06 mm less than that of intact group 2.17 mm, while the deformations of model B and model C were both higher than that of intact group, with the distributions of 2.39 mm and 2.33 mm. (2) Under various loads, the stress in model A group was also the smallest. Under 2 100 N, the stress peak in model A was 297.31 MPa, distributed at the joint position of anti-rotation screw and locking screw, while the stress peak in model B was 543.18 MPa, distributed at the fracture joint position of the third screw in the inverted triangle. However, the deformation and stress of model C were intermediate between model A and model B, and the maximum stress peak value was distributed at the bottom hollow of the cannulated screw fracture, reaching 315.61 MPa at 2 100 N. (3) The compressive stiffness and stress analysis of models of the three groups showed that model A < model C < model B. (4) It is concluded that the mechanical stability of femoral neck system for femoral neck fracture is better than that of three and four cannulated screws fixation, and it can effectively prevent femoral neck shortening. Femoral neck system is a recommended internal fixation method for unstable femoral neck fractures. © 2023, Publishing House of Chinese Journal of Tissue Engineering Research. All rights reserved.     

Diffuse distribution of bone cement in percutaneous vertebroplasty reduces the incidence of refracture of adjacent vertebral bodies北大核心

BACKGROUND: Percutaneous vertebroplasty is one of the effective treatments for osteoporotic vertebral compression fractures. The distribution of bone cement in the vertebral body will influence the clinical efficacy. OBJECTIVE: To investigate the influence of the distribution of bone cement in percutaneous vertebroplasty on the early postoperative outcomes after osteoporotic vertebral compression fractures. METHODS: A total of 132 patients, including 52 males and 80 females, with a mean age of (76.3±8.2) years who diagnosed as osteoporotic vertebral compression fractures in First Hospital of Shanxi Medical University from January 2017 to June 2019 were enrolled. All patients were divided into underdispersion group (n=54) and diffuse distribution group (n=78) according to the pattern of cement distribution on postoperative X-rays. Visual analogue scale scores postoperatively, the height of anterior edge and midline of injured vertebrae, Cobb angle of local kyphosis and the incidence of complications after 1-year follow-up were compared between the two groups. The trial was performed in accordance with the relevant ethical requirements for research in the First Hospital of Shanxi Medical University. RESULTS AND CONCLUSION: (1) The visual analogue scale scores were lower at 2 days, 1 and 6 months after operation than those before operation in the two groups (P < 0.05). The visual analogue scale scores at 1 month after operation in the underdispersion group were higher than those in the diffuse distribution group (P < 0.05), and there was no significant difference between the two groups at 2 days and 6 months after operation (P > 0.05). (2) Cobb angle and vertebral body height improved in both groups postoperatively compared to preoperatively (P < 0.05). The difference in Cobb angle and vertebral body height was not statistically significant between the two groups (P > 0.05). (3) The rate of bone cement infiltration was not significantly different between the two groups (P > 0.05). Incidence of recurrent fractures in adjacent vertebrae was lower in the diffuse distribution group than that in the underdispersion group (P < 0.05). (4) These findings confirm that percutaneous vertebroplasty is an effective treatment for osteoporotic vertebral compression fractures. The distribution of bone cement in the vertebral body will affect the surgical results. The bone cement is diffusely distributed, which may reduce the incidence of recurrent fractures in adjacent vertebrae. © 2022, Publishing House of Chinese Journal of Tissue Engineering Research. All rights reserved.     

Patient-specific finite element modeling of the Cardiokinetix Parachute® device: effects on left ventricular wall stress and function

The Parachute^® (Cardiokinetix, Inc., Menlo Park, California) is a catheter-based device intended to reverse left ventricular (LV) remodeling after antero-apical myocardial infarction. When deployed, the device partitions the LV into upper and lower chambers. To simulate its mechanical effects, we created a finite element LV model based on computed tomography (CT) images from a patient before and 6 months after Parachute^® implantation. Acute mechanical effects were determined by in silico device implantation (VIRTUAL-Parachute). Chronic effects of the device were determined by adjusting the diastolic and systolic material parameters to better match the 6-month post-implantation CT data and LV pressure data at end-diastole (ED) (POST-OP). Regional myofiber stress and pump function were calculated in each case. The principal finding is that VIRTUAL-Parachute was associated with a 61.2 % reduction in the lower chamber myofiber stress at ED. The POST-OP model was associated with a decrease in LV diastolic stiffness and a larger reduction in myofiber stress at the upper (27.1 %) and lower chamber (78.4 %) at ED. Myofiber stress at end-systole and stroke volume was little changed in the POST-OP case. These results suggest that the primary mechanism of Parachute^® is a reduction in ED myofiber stress, which may reverse eccentric post-infarct LV hypertrophy.     

Comparative clinical efficacy of polymethyl methacrylate and self-solidifying calcium phosphate cement in vertebroplasty: A meta-analysis北大核心

OBJECTIVE: Vertebroplasty is widely used in the treatment of osteoporotic vertebral fractures. At present, polymethyl methacrylate is still the most commonly used filling material for strengthening vertebral body, but it is not the most ideal filling material. Self-curing calcium phosphate cement is a new filling material developed in recent years, which can naturally heal with bone tissue and be absorbed and replaced by the human body. This meta-analysis systematically analyzed the clinical efficacy and safety of polymethyl methacrylate and self-solidifying calcium phosphate cement in vertebroplasty. METHODS: China National Knowledge Infrastructure, Wanfang database, Chinese Biomedical Medicine database, PubMed, EMbase, and Cochrane Library database were retrieved for clinical control studies regarding with polymethyl methacrylate and self-solidifying calcium phosphate cement treatment of osteoporotic vertebral compression fracture. The retrieval period was from the database inception to July 2020. The visual analogue scale score, vertebral kyphosis Cobb angle, vertebral body height, bone cement leakage rate, adjacent vertebral fracture rate, Oswestry dysfunction index, and clinical curative effect were used as the outcome indexes. All the literature screening, data extraction and research quality evaluation were carried out independently by two reviewers. In addition, the Cochrane Collaboration tool and the Newcastle-Ottawa scale were used to evaluate the quality of randomized controlled trials and cohort studies, respectively. RevMan 5.4 software was used for meta-analysis. RESULTS: (1) A total of nine studies involving 593 patients were included in the meta-analysis; five of which were randomized controlled trials, and four were retrospective cohort studies. All of the selected studies were of high quality. (2) Meta-analysis results showed that there was no significant difference between the two filling materials in the following aspects, including visual analogue scale score (SMD=-0.45, 95%CI:-1.10-0.21, P=0.18), Cobb angle of vertebral kyphosis (MD=-0.16, 95%CI:-0.43-0.11, P=0.24), height of vertebral body (SMD=0.13, 95%CI:-0.12-0.37, P=0.32), leakage rate of bone cement (OR=1.30, 95%CI:0.67-2.54, P=0.44), Oswestry disability index (MD=3.31, 95%CI:-1.34-7.97, P=0.16), and clinical effective rate (OR=1.00, 95%CI:0.14-7.27, P=1.00). However, in terms of new fractures of adjacent vertebrae, the calcium phosphate cement group was significantly better than the polymethyl methacrylate group (OR=2.17, 95%CI:1.04-4.51, P=0.04). CONCLUSION: The application of calcium phosphate cement in vertebroplasty has a significant advantage in reducing adjacent vertebral fractures compared with polymethyl methacrylate. The curative effect is similar in pain visual analogue scale score, vertebral kyphosis Cobb angle, vertebral body height, bone cement leakage rate, and Oswestry dysfunction index. However, more high-quality randomized controlled trials are needed to provide more sufficient evidence. © 2022, Publishing House of Chinese Journal of Tissue Engineering Research. All rights reserved.     

Phenylephrine effects on the morphology of osteoblasts and expression of nicotinamide phosphoribosyltransferase under oxidative stress北大核心

BACKGROUND: Phenylephrine has been proved to exert a protective effect on radiant-induced salivary gland and epithelial cell injuries, but its effect on hydrogen peroxide (H2O2)-induced oxidative stress in osteoblasts are not fully understood. OBJECTIVE: To explore the effect of phenylephrine on H2O2-induced oxidative stress in osteoblasts, and to explore the mechanism underlying the regulation by the expression level of nicotinamide phosphoribosyltransferase (Nampt). METHODS: Primary osteoblasts were cultured and randomly divided into four groups: blank control group, H2O2 group, phenylephrine group, and combination group (0.5 hour pretreatment of 1×10-5 mol/L phenylephrine, and then given 300 µmol/L H2O2). The morphology of osteoblasts was observed at different time points. Osteoblasts were collected after 24-hour culture, and total RNA and protein were then extracted to detect the mRNA and protein expression levels of Nampt by RT-PCR and western blot assay, respectively. RESULTS AND CONCLUSION: Compared with the blank control group, reduced osteoblasts and evident cell shrinks were observed in the H2O2 group, while the number of osteoblasts significantly increased in the combined group compared with the H2O2 group at 12, 24 and 48 hours of culture. RT-PCR results showed that the mRNA level of Nampt in the H2O2 group was reduced by 31.23% of that in the blank control group, while the mRNA level of Nampt in the combination group was dramatically increased by 206.20% of that in the H2O2 group at 24 hours of culture (both P < 0.05). Furthermore, western blot assay findings revealed that the protein level of Nampt in the H2O2 group was reduced by 67.98% of that in the blank control group, while the protein level of Nampt in the combination group was increased by 152.25% of that in the H2O2 group at 24 hours of culture (both P < 0.05). Our results indicate that phenylephrine can alleviate the shrink and atrophy of osteoblasts caused by H2O2, thereby exerting protective effect by up-regulating the mRNA and protein levels of Nampt that may be a regulatory gene. © 2018, Journal of Clinical Rehabilitative Tissue Engineering Research. All rights reserved.     

Immunomodulatory effects of deferoxamine and interferon gamma on human dental pulp stem cells北大核心

BACKGROUND: Immune rejection is a great challenge for tissue or organ transplantation, and immunosuppressors often bring serious side effects to patients. The immunosuppressive effect of mesenchymal stem cells brings new hope for the treatment of immune rejection. OBJECTIVE: To explore the effect of combined action of deferoxamine and interferon-γ on the immunomodulatory ability of human dental pulp stem cells. METHODS: After pretreatment of human dental pulp stem cells with deferoxamine or interferon-γ or their combination, the proliferation of cells was detected with cell counting kit-8. The mRNA expression of some gene mRNA was examined by Q-PCR. The secretion of some immune regulatory factors was determined using ELISA. Thereafter, pretreated human dental pulp stem cells were co-cultured with mouse spleen lymphocytes, and then the proliferation of lymphocytes was detected by CFSE labeling by flow cytometry. After allogenic skin transplantation, mice were injected with PBS, human dental pulp stem cells or pretreated human dental pulp stem cells into tail vein immediately. The survival time of skin grafts was recorded. The pathology and immunohistochemistry of skin grafts were examined. Moreover, the proportion of Treg cells in spleen of transplanted mice was measured. RESULTS AND CONCLUSION: (1) Deferoxamine or interferon-γ pretreatment inhibited the growth of human dental pulp stem cells, and the inhibition of deferoxamine was more significant than interferon-γ. (2) Pretreatment of deferoxamine combined with interferon-γ significantly increased the gene expression of vascular endothelial growth factor, interleukin 6, transforming growth factor β1, cyclooxygenase 2, human leukocyte antigen G, tumor necrosis factor A inducible protein 6 and interleukin 10, and promote secretion of interleukin 6, transforming growth factor β1 and prostaglandin E2. (3) The results of in vivo experiments confirmed that human dental pulp stem cells pretreated with deferoxamine combined with interferon-γ prolonged the survival time of mouse allograft skin, reduced the infiltration of CD4+T, CD8+T and macrophages at the grafted skin, and increased the proportion of Treg cells in the spleen of recipient mice. (4) It is concluded that deferoxamine combined with interferon-γ pretreatment enhanced the immunomodulatory effect of human dental pulp stem cells, and inhibited the immune rejection of skin allografts. © 2022, Publishing House of Chinese Journal of Tissue Engineering Research. All rights reserved.     

Atorvastatin effects on proliferation and apoptosis of rat bone marrow-derived endothelial progenitor cells in vitro北大核心

BACKGROUND: Atorvastatin has a cardiovascular protective effect that significantly improves endothelial function and promotes the mobilization, migration, and differentiation of endothelial progenitor cells. However, the screening of atorvastatin concentration for in vitro cell culture is not well documented. OBJECTIVE: To investigate the effects of different concentrations of atorvastatin on rat bone marrow-derived EPCs growth characteristics. METHODS: Bone marrow mononuclear cells from Sprague-Dawley rats were induced in selective culture fluid to culture EPCs. Immunofluorescence staining was used to identify cell surface markers. Harvested EPCs were divided into control group and atorvastatin groups with four different concentrations (0.01, 0.1, 1, and 10 µmol/L) for culture. The growth and proliferation of EPCs were observed under light microscope and MTT assay. Flow cytometry was used to detect apoptosis in EPCs. Nitric oxide and endothelial nitric oxide synthase levels in the culture fluid were measured by nitrate reductase method. RESULTS AND CONCLUSION: The number of cells tended to increase in the control and atorvastatin groups, and it was highest in the 1 µmol/L atorvastatin group. The cell number in the 10 µmol/L atorvastatin group began to decrease at 7 days of culture. Among the five groups, the apoptotic rate of cells was lowest in the 1 µmol/L atorvastatin group and highest in the 10 µmol/L atorvastatin group. The levels of nitric oxide and endothelial nitric oxide synthase were significantly higher in the 0.01, 0.1 and 1.0 µmol/L atorvastatin groups compared with the control group (P < 0.01), but lower in the 10 µmol/L atorvastatin group compare with the other groups (P < 0.01). Overall, atorvastatin can promote the proliferation of endothelial progenitor cells and reduce apoptosis by increasing the production of endothelial nitric oxide synthase and nitric oxide, and 1 µmol/L atorvastatin is most suitable for the EPCs culture. © 2018, Journal of Clinical Rehabilitative Tissue Engineering Research. All rights reserved.     

Specifying the effects of physician's communication on patients’ outcomes: A randomised controlled trial

ObjectiveTo experimentally test the effects of physician's affect-oriented communication and inducing expectations on outcomes in patients with menstrual pain.MethodsUsing a 2 × 2 RCT design, four videotaped simulated medical consultations were used, depicting a physician and a patient with menstrual pain. In the videos, two elements of physician's communication were manipulated: (1) affect-oriented communication (positive: warm, emphatic; versus negative: cold, formal), and (2) outcome expectation induction (positive versus uncertain). Participants (293 women with menstrual pain), acting as analogue patients, viewed one of the four videos. Pre- and post video participants’ outcomes (anxiety, mood, self-efficacy, outcome expectations, and satisfaction) were assessed.ResultsPositive affect-oriented communication reduced anxiety (p < 0.001), negative mood (p = 0.001), and increased satisfaction (p < 0.001) compared to negative affect-oriented communication. Positive expectations increased feelings of self-efficacy (p < 0.001) and outcome expectancies (p < 0.001), compared to uncertain expectations, but did not reduce anxiety. The combination of positive affect-oriented communication and a positive expectation reduced anxiety (p = 0.02), increased outcome expectancies (p = 0.01) and satisfaction (p = 0.001).ConclusionBeing empathic and inducing positive expectations have distinct and combined effects, demonstrating that both are needed to influence patients’ outcomes for the best.Practice implicationsContinued medical training is needed to harness placebo-effects of medical communication into practice.     

Within-family outliers: segregating alleles or environmental effects? A linkage analysis of height from 5815 sibling pairs

Most information in linkage analysis for quantitative traits comes from pairs of relatives that are phenotypically most discordant or concordant. Confounding this, within-family outliers from non-genetic causes may create false positives and negatives. We investigated the influence of within-family outliers empirically, using one of the largest genome-wide linkage scans for height. The subjects were drawn from Australian twin cohorts consisting of 8447 individuals in 2861 families, providing a total of 5815 possible pairs of siblings in sibships. A variance component linkage analysis was performed, either including or excluding the within-family outliers. Using the entire dataset, the largest LOD scores were on chromosome 15q (LOD 2.3) and 11q (1.5). Excluding within-family outliers increased the LOD score for most regions, but the LOD score on chromosome 15 decreased from 2.3 to 1.2, suggesting that the outliers may create false negatives and false positives, although rare alleles of large effect may also be an explanation. Several regions suggestive of linkage to height were found after removing the outliers, including 1q23.1 (2.0), 3q22.1 (1.9) and 5q32 (2.3). We conclude that the investigation of the effect of within-family outliers, which is usually neglected, should be a standard quality control measure in linkage analysis for complex traits and may reduce the noise for the search of common variants of modest effect size as well as help identify rare variants of large effect and clinical significance. We suggest that the effect of within-family outliers deserves further investigation via theoretical and simulation studies.     

Edaravone effects on the expression levels of collagen type i and iv after spinal cord injury in rats北大核心

BACKGROUND: Edaravone, an effective free radical scavenger, has been reported to significantly improve the rehabilitation of limb locomotion after spinal cord injury (SCI), but the underlying mechanism remains unclear. OBJECTIVE: To explore the mechanism underlying edaravone promoting the recovery of limb locomotion in rats with SCI by observing the Basso, Beattie, Bresnahan scores and expression levels of collagen type I and IV. METHODS: Thirty-six rats were randomly allocated into three groups (n=12 per group): sham group (laminectomy plus intraperitoneal injection of normal saline), model group (SCI model by NYU impactor plus intraperitoneal injection of normal saline), and edaravone group (SCI model by NYU impactor plus intraperitoneal injection of edaravone). All rats were given the administration at the 1st day post-SCI for consecutive 7 days. The Basso, Beattie, Bresnahan scores were tested at 1, 3, 5 and 7 days post treatment. On day 7, all rats were sacrificed to remove the spinal cord, and the morphology of neurons in the spinal cord were observed by Nissl staining; the expression levels of collagen type I and IV were detected by immunohistochemistry and western blot assays. RESULTS AND CONCLUSION: Compared with the model group, the Basso, Beattie, Bresnahan scores in the edaravone group were significantly increased at day 5 post treatment (P < 0.05). Nissl staining showed a clear boundary between grey matter and white matter, and a large nucleolus in the neurocytoplasm in the sham group; there was a complete structure of neurons, slight cellular swelling and small hematoma area in the edaravone group; many and large cavitations and swollen nucleus were found in the neurons, even without nucleolus. Immunohistochemistry and western blot assay results showed that the expression levels of collagen type I and IV in the edaravone group were significantly higher than those in the model group (P < 0.05). These results indicate that edaravone can promote the recovery of limb locomotion of rats with SCI, probably via up-regulating the expression levels of collagen type I and IV. © 2018, Journal of Clinical Rehabilitative Tissue Engineering Research. All rights reserved.     

A comparative study on serum-free and serum culture methods of human umbilical cord mecenchymal stem cells北大核心

BACKGROUND: Studies have shown increasing risks and problems in the serum culture system, such as immune rejection, batch differences and virus risk. In addition, with the discovery and application of exosomes, the serum-free culture system is becoming an increasing concern. OBJECTIVE: To compare the similarities and differences between the serum-free culture system and the traditional serum culture system, which lays the foundation for the clinical transformation of human umbilical cord mesenchymal stem cells (hUCMSCs) and provides experimental data. METHODS: Umbilical cord was collected from term infants of cesarean section under aseptic condition, and hUCMSCs were isolated and cultured by expiant tissue technique. hUCMSCs was cultured with 10% fetal bovine serum (FBS) and 15% serum substitutes (AGS) from the criginal generation. Then an inverted microscope was used to observe cell morphological changes. Flow cytometry was used to detect cell surface markers. Cell counting kit-8 was used to detect cell proliferation. Induced differentiation experiment was used to detect cell differentiation potential. Western Blot was used to detect the protein levels of oct4, nanog and sox2. RESULTS AND CONCLUSION: Under the inverted microscope, hUCMSCs cultured with AGS showed more uniform vortex-like growth, and those cultured with FBS gradually appeared with cell differentiation or aging with the increase cf cell generations. hUCMSCs cultured by both methods expressed CD73,CD90 and CD105 but lowly expressed CD34 and CD45, and there was no significant difference between the two culture methods. FBS method was superior to AGS method in proliferation ability. Results from the induced differentiation experiments showed that hUCMSCs cultured by both methods had adipogenic, osteogenic and chondrogenic abilitis, and there was no significant difference between the two culture methods. hUCMSC cultured by both methods expressed oct4 and nanog but showed no significant difference in level, while the expression of sox2 was significantly higher in the hUCMSCs cultured by AGS than by FBS (P < 0.05). To conclude, the hUCMSCs cultured with AGS are in accordance with the international standards of mesenchymal stem cells. The AGS method as an alternative to the FBS method can become a preferred method for hUCMSCs culture. © 2018, Journal of Clinical Rehabilitative Tissue Engineering Research. All rights reserved.