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18 September 2019, Volume 23 Issue 26 Previous Issue    Next Issue

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Cobalt-chromium particles inducing preosteoblasts may aggravate periprosthetic inflammation Jiang Jianhao, Li Peng, Du Gangqiang, Liu Hongzhi, Wang Hui, Zhang Kai, Yang Shangyou, Yang Shuye 2019, 23 (26):  4101-4108.  doi: 10.3969/j.issn.2095-4344.1346 Abstract ( 16 )   PDF (29136KB) ( 42 )   Save BACKGROUND: Arthroplasty has been the most effective treatment for the end-stage osteoarthritis. However, aseptic loosening is the main long-term complication of arthroplasty. How to ameliorate aseptic loosening is an issue of concern. OBJECTIVE: To investigate the biological behavior of preosteoblasts induced with cobalt-chromium particles during aseptic loosening process. METHODS: (1) In vitro experiment: preosteoblasts were cultured in an osteoblast-induction medium and induced with different doses (0.3 or 1.25 g/L) of cobalt-chromium particles. (2) In vivo experiment: titanium screws were implanted to proximal tibia of server combined with immune-deficiency mice to simulate knee joint arthroplasty. Cobalt-chromium particles inducing MC3T3-E1 (5×105) were intra-articularly injected into the implanted knee at 1 week after surgery. Stable group (n=6): screw implanted mice without local particle insertion and cells transfusion; loosening group (n=6): mice were given an intra-articular injection of cobalt-chromium particles (4×104) before screw implantation; cobalt-chromium group: mice were given an intra-articular injection of preosteoblasts induced by cobalt-chromium particles and cobalt-chromium particles (4×104) before screw implantation. RESULTS AND CONCLUSION: (1) In vitro experiment: with the increasing of cobalt-chromium particles, alkaline phosphatase and osteogenic gene expression was decreasing. (2) In vivo experiment: intra-articular injection of cobalt-chromium particles inducing MC3T3-E1 cells resulted in thicker peri-implant pseudomembrane, reduced the shear strength of bone-implant, decreased bone mineral density and bone volume, and increased the number of positive cells for tartrate-resistant acid phosphatase. (3) These results indicate that cobalt-chromium particles inhibit the growth, maturation and functions of preosteoblastic cells. Cobalt-chromium particles inducing preosteoblasts may aggravate periprosthetic inflammation and promote osteoclastogenesis. Figures and Tables | References | Related Articles | Metrics

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Construction of tissue engineered bone by poly(lactic-co-glycolic acid) scaffold carrying human bone marrow mesenchymal stem cells Chen Jiao, Shu Liping, Li Xuanze, Liu Qin, Wu Ying, Liu Yin, Wang Weiyu, Liu Jun,Ye Chuan, Ma Minxian 2019, 23 (26):  4109-4114.  doi: 10.3969/j.issn.2095-4344.1347 Abstract ( 332 )   PDF (24016KB) ( 89 )   Save BACKGROUND: Poly(lactic-co-glycolic acid) (PLGA) is one of the few biomaterials approved for experimental and clinical use. It has good biocompatibility, biodegradability and excellent mechanical properties, and is a good scaffold carrier in tissue engineering. OBJECTIVE: To investigate the in vitro biocompatibility and in vivo ectopic osteogenic differentiation of PLGA nano-scaffold material carrying human bone marrow mesenchymal stem cells. METHODS: 150 g/L PLGA solution was electrospun into fiber membrane by electrospinning technique. Passage 3 human bone marrow mesenchymal stem cells (harvesting of human bone marrow sample was approved by Ethics Committee of Affiliated Hospital of Guizhou Medical University, China) were seeded into PLGA nano-scaffold and cultured with osteogenic induction medium for 7 days. After 4',6-diamidino-2-phenylindole staining and acridine orange fluorescent staining, the growth of cells/scaffold complex was observed under scanning electron microscope. Passage 3 human bone marrow mesenchymal stem cells were seeded on PLGA nano-scaffold and cultured with osteogenic induction medium (experimental group) or without (control group). After 14 days of culture, cell-scaffold complex was subcutaneously implanted into the nude mice. At 12 weeks after implantation, the cell-scaffold complex was removed and stained with hematoxylin-eosin, alizarin red, alkaline phosphatase, and collagen I immunohistochemical staining to observe ectopic osteogenesis.   RESULTS AND CONCLUSION: 4',6-Diamidino-2-phenylindole staining and acridine orange fluorescent staining revealed that human bone marrow mesenchymal stem cells adhered well on the surface of the scaffold. Scanning electron microscopy showed that after osteogenic induction, human bone marrow mesenchymal stem cells grew well on PLGA scaffold, and cells produced abundant extracellular matrix. At 12 weeks after implantation, the cells were positive for alizarin red staining, alkaline phosphatase staining and collagen type I immunohistochemical staining. Positive expression in the experimental group was stronger than that in the control group. Hematoxylin-eosin staining showed numerous osteoblasts and typical bone lacunaes in the experimental group and a small amount of bone tissue in the control group. These results suggest that PLGA nano-scaffold material exhibits good biocompatibility and in vivo ectopic osteogenic capacity, and can be used as scaffold material in bone tissue engineering. Figures and Tables | References | Related Articles | Metrics

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Resveratrol reduces tumor nuclear factor-α expression in wear-particle-treated macrophages by regulating the level of intracellular oxidative stress Liu Wenhua, Liang Jinfeng, Deng Shaojie 2019, 23 (26):  4115-4120.  doi: 10.3969/j.issn.2095-4344.1398 Abstract ( 23 )   PDF (25656KB) ( 40 )   Save BACKGROUND: Numerous in vitro cell and animal experiments have shown that resveratrol exhibits anti-oxidative stress, anti-inflammatory, anti-viral, anti-tumor and anti-aging activities and it also has bone-protecting effect. OBJECTIVE: To investigate the regulatory effect of resveratrol on oxidative stress and inflammatory response of RAW264.7 macrophages induced by titanium wear-particles. METHODS: The RAW264.7 macrophages were treated with different doses of resveratrol (0, 10, 20, 40, 80, 160 μmol/L) for 24 hours. Cell viability was detected using WST-1 method. Resveratrol doses that did not produce significant change in cell viability were used in the subsequent experiments. RAW264.7 cells were divided into five groups. In the control group, cells were routinely cultured. In the titanium group, RAW264.7 macrophages were treated with titanium particles for 12 hours. In the low-, medium-, and high-dose resveratrol groups, RAW264.7 macrophages were pre-treated with 10, 20, 40 μmol/L resveratrol for 4 hours, and then they were treated with titanium particles for 12 hours. Thereafter, cells and cell supernatant were collected for measurement of intracellular reactive oxygen species generation using flow cytometry. Total RNA was extracted from cells for measuring mRNA level of anti-oxidative enzymes (Cu/Zn superoxide dismutase, Mn superoxide dismutase, glutathione peroxidase, glutathione reductase and catalase) and tumor necrosis factor-α. Cell supernatant was used for measuring the level of TNF-α using ELISA. RESULTS AND CONCLUSIONS: Treatment with resveratrol (10, 20, and 40 μmol/L) did not affect the viability of RAW264.7 macrophages. Therefore, these doses (10, 20, and 40 μmol/L) were used in the following experiments. Intracellular reactive oxygen species generation in the titanium group was significantly increased compared with the control group (P < 0.05). Resveratrol decreased reactive oxygen species generation in a dose-dependent manner compared with the titanium group (P < 0.05). Compared with the control group, Mn superoxide dismutase and glutathione peroxidase mRNA levels significantly decreased (P < 0.05), glutathione reductase and catalase mRNA levels significantly increased (P < 0.05) in the titanium group. Compared with the titanium group, Mn superoxide dismutase and Cu/Zn superoxide dismutase mRNA levels significantly increased in the medium- and high-dose resveratrol groups (P < 0.05), and catalase mRNA level significantly increased in the low-, medium-, and high-dose resveratrol groups (P < 0.05). The mRNA level and secretion of tumor necrosis factor-α in the titanium group were significantly increased than in the control group (P < 0.05). Compared with the titanium group, low-, medium-, and high-dose resveratrol decreased the mRNA level and secretion of tumor necrosis factor-α (P < 0.05). These results indicate that resveratrol can effectively enhance the transcription of antioxidant stress-related enzymes in macrophages stimulated by titanium particles, reduce the level of intracellular oxidative stress, and reduce the release of inflammatory factor tumor necrosis factor-α. Figures and Tables | References | Related Articles | Metrics

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Evaluation of biosafety of porous magnesium alloy scaffolds for jaw defects Wang Liang, Guo Yuxing, Huang Hua, Yuan Guangyin, Zhang Lei 2019, 23 (26):  4121-4128.  doi: 10.3969/j.issn.2095-4344.1736 Abstract ( 28 )   PDF (982KB) ( 41 )   Save BACKGROUND: Biosafety and other advantages of biomedical magnesium alloy products have been confirmed, but the biosafety of porous scaffold materials prepared by changing the manufacturing process and product morphology based on the alloy composition is unclear. OBJECTIVE: To investigate the biosafety properties of a biomedical porous magnesium alloy scaffold. METHODS: Extracts of porous magnesium alloy scaffold materials were prepared, and in vitro cytotoxicity experiment, in vitro hemolysis experiment, intrauthelial reaction experiment, pyrogen experiment, acute systemic toxicity experiment and genetic toxicity experiment were conducted according to GB/T16886 biological evaluation series of medical devices. The effects of extracts of porous magnesium alloy scaffold materials on the activity of human bone marrow mesenchymal stem cells and the structural integrity of blood cell membrane, and the effects on the animal endothelial tissue, body temperature, body mass and chromosomal structure of polychromatic red blood cells were evaluated. Animal mandibular defect model was prepared, and porous magnesium alloy was implanted into the defect area to evaluate its influence on serum and urine Mg2+ concentration, blood cell number and important organs. The study was approved by the Experimental Animal Ethics Committee of Peking University Health Science Center (approval number: LA2017217). RESULTS AND CONCLUSION: (1) The extracts of porous magnesium alloy scaffolds could promote the proliferation of bone marrow mesenchymal stem cells, and the cytotoxicity was 0. (2) The hemolysis rate of the extracts of porous magnesium alloy scaffold material was 0.94%, and the response to intradermal stimulation was 0, which met the requirements of medical device hemolysis experiment (< 5%) and intradermal reaction experiment (final score ≤ 1.0). (3) After the injection of porous magnesium alloy extract, the increased degree of body temperature was ≤ 0.4 oC and elevated total degree ≤ 0.8 oC in all animals, which conformed to the requirements of the medical equipment of heat experiment. (4) The porous magnesium alloy extract caused no systemic toxicity or damaged chromosomal structure of polychromatic erythrocytes. (5) Within 1 month after implantation of porous magnesium alloy scaffold material into the bone defect, there was no significant change in serum and urine Mg2+ concentration, the red blood cells, white blood cells and platelets were in the normal range, and no obvious pathological changes were found in the heart, liver, kidney and spleen tissues. (6) These results imply that porous magnesium alloy scaffold has excellent biosafety property. Figures and Tables | References | Related Articles | Metrics

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Percutaneous vertebroplasty with different viscosities of bone cement for treatment of thoracolumbar metastases   Li Minghui, Liu Yang, Zhang Mi, Xu Feng 2019, 23 (26):  4129-4135.  doi: 10.3969/j.issn.2095-4344.1348 Abstract ( 21 )   PDF (30538KB) ( 49 )   Save BACKGROUND: Complications such as bone cement leakage are more common in percutaneous vertebroplasty. The choice of different filling materials has become an important factor affecting the surgical outcome. OBJECTIVE: To investigate the clinical efficacy of percutaneous vertebroplasty with different viscosities of bone cement for treatment of thoracolumbar metastases. METHODS: A total of 101 patients with bone metastases of malignant tumors, aged 52-87 years, who were admitted during June 2012 to October 2017 by Fifth Hospital in Wuhan, China were randomly assigned to undergo percutaneous vertebroplasty with Confidence high-viscosity bone cement (observation group, n=49, 103 vertebrae) or Heraeus low-viscosity bone cement (control group, n=52, 107 vertebrae). Within 48 hours after surgery, bone cement leakage was observed by imaging examination. The pain, clinical function and the height of the anterior border of the vertebral body as well as the kyphosis of the vertebral body were compared before surgery, 48 hours after surgery, and at the last follow-up. Adjacent vertebral fractures were statistically analyzed. This study was approved by the Ethics Committee of the Fifth Hospital in Wuhan. RESULTS AND CONCLUSION: After surgery, the pain and clinical function of patients in the two groups were significantly improved compared with those before surgery (P < 0.05). There was no significant difference in pain and clinical function between the two groups at the same time point after surgery (P > 0.05). The height of the anterior border of the vertebral body and the degree of kyphosis of the vertebral body were significantly increased after surgery (P < 0.05). At different time points after surgery, the height of the anterior border of the vertebral body and the degree of kyphosis of the vertebral body were more obviously increased in the experimental group than in the control group (P < 0.05). Bone cement leakage rate in the observation group was significantly lower than that in the control group (16.50% vs. 22.43%, P < 0.05). There were no serious complications, such as recurrent fracture of adjacent vertebral bodies and pulmonary embolism, during the follow up period. These results suggest that high- and low-viscosity bone cement percutaneous vertebroplasty for treatment of thoracolumbar metastases can alleviate pain and improve quality of life with exact clinical efficacy and high safety. High-viscosity bone cement percutaneous vertebroplasty better recovers the height of the anterior border of the vertebral body, reduces the Cobb angles of kyphosis of the vertebral body, and lowers the risk of bone cement leakage than low-viscosity bone cement percutaneous vertesroplasty. Figures and Tables | References | Related Articles | Metrics

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Physical and chemical properties of carbonate apatite monolith treated by three ammonium phosphate solutions Lin Xin, Hou Min 2019, 23 (26):  4136-4141.  doi: 10.3969/j.issn.2095-4344.1349 Abstract ( 24 )   PDF (1307KB) ( 64 )   Save BACKGROUND: In our previous study, we prepared calcite monolith by carbonation of Ca(OH)2 and then synthesized dahllite agglomerates with encouraging physical and chemical properties after treatment with NH4H2PO4 solution at low temperature. But it had low carbonic acid content, which is considered to be associated with the low pH values of ammonium dihydrogen phosphate solution. OBJECTIVE: To compare the effects of ammonium phosphate solutions at different pH values on the physical and chemical properties of the carbonate apatite bone substitute material prepared by calcite and find the optimal ammoniumm phosphate solution for fabrication of carbonate apatite monolith with excellent performance at low temperature.  METHODS: The agglomerated calcium hydroxide was carbonated to form calcite. The prepared calcite was soaked in three 1 mol/L ammonium phosphate solutions (NH4H2PO4, (NH4)2HPO4, (NH4)3PO4) at 60°C respectively. After 1, 4, 7 and 14 days of soaking, diametral tensile strength determination, X-ray diffraction analysis, Fourier transform infrared spectroscopy studies, and scanning electron microscopy were performed. The results were analyzed by comparison. RESULTS AND CONCLUSION: X-ray diffraction analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, and diametral tensile strength determination results showed that after 14 days of treatment with three ammonium phosphate solutions, CaCO3 had completely transformed into carbonate apatite. The reaction rate was fastest in the NH4H2PO4 solution, with the highest diametral tensile strength of 10 MPa, but relative lower carbonate content (4.80±0.5)%. The diametral tensile strength of final product was 6 MPa after treatment by both (NH4)2HPO4 and (NH4)3PO4 solution. It is adequate for bone substitute used in the low-bearing parts. Chemical analyses showed that the carbonate content of the product treated by (NH4)3PO4 solution was (7.25±0.81)%, which was extremely similar to that of bone. In addition, there was a high amount of B-type carbonate apatite. These results suggest that carbonate apatite with sufficient diametral tensile strength. By comparison, the carbonate apatite produced with (NH4)3PO4 solution is the most ideal product. Figures and Tables | References | Related Articles | Metrics

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Dextran/poly(lactic-co-glycolic acid) microspheres combined with three growth factors promote neovascularization in ischemic lower limbs of rats Zhu Xianhua, Chen Feng, Liu Chongdong, Zhou Wei, Tang Xinhua 2019, 23 (26):  4142-4147.  doi: 10.3969/j.issn.2095-4344.1353 Abstract ( 21 )   PDF (840KB) ( 36 )   Save BACKGROUND: The dextran/poly(lactic-co-glycolic acid) (PLGA) microspheres as a sustained release drug delivery system enables the drug to maintain an effective concentration at the site of action. OBJECTIVE: To investigate the effects of dextran/PLGA microspheres carrying granulocyte colony-stimulating factor, erythropoietin and vascular endothelial growth factor on the neovascularization of ischemic lower limb of rats. METHODS: Dextran/PLGA microspheres carrying granulocyte colony-stimulating factor, erythropoietin, and vascular endothelial growth factor were prepared and their surface morphology was observed by scanning electron microscopy. The encapsulation efficiency and cumulative release rate were detected by ELISA method. Dextran/PLGA microspheres carrying three growth factors were mixed with fibrin glue to prepare a growth factor dextran/PLGA/fibrin glue complex. Right lower limb ischemia models were produced in 24 male Sprague-Dawley rats (Laboratory Animal Center, Jiangsu University of Traditional Chinese Medicine, China). These animal models were randomly divided into two groups (n = 12/group). In the experimental group, dextran/PLGA/fibrin glue complex carrying three growth factors was injected into the inner thigh muscle at 5 points. In the control group, dextran/PLGA/fibrin glue complex without growth factors was identically injected. At 1 week after surgery, the muscle tissue around the injection site was harvested for immunohistochemistry to detect the expression of proliferating cell nuclear antigen, Bcl-2, stromal cell-derived factor 1, and C-X-C chemokine receptor type 4. At 4 weeks after surgery, the muscle tissue around the injection site was harvested for histological and immunohistochemical examination to measure capillary density. This study was approved by Animal Ethics Committee of Nanchang University School of Medicine, China. RESULTS AND CONCLUSION: The dextran/PLGA microspheres were spherical and had a smooth surface with a diameter of 40-120 μm. The encapsulation efficiency of dextran/PLGA microspheres carrying granulocyte colony-stimulating factor, erythropoietin, and vascular endothelial growth factor was 84%, 85%, and 82%, respectively. The 4-week cumulative release rate was 89.5%, 90.3%, 91.2%, respectively. The expression of proliferating cell nuclear antigen, Bcl-2, stromal cell-derived factor 1, and C-X-C chemokine receptor type 4 in the experimental group was significantly higher than that in the control group. Capillary density and α-smooth muscle actin-positive vascular density in the experimental group were significantly higher than those in the control group (P < 0.05). These results suggest that dextran/PLGA microspheres carrying multiple growth factors for treatment of lower limb ischemia is a promising therapeutic method. Figures and Tables | References | Related Articles | Metrics

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Changes of vascular endothelial growth factor after repair of pig mandibular defects by nano-hydroxyapatite/collagen composite Li Dongmei, Liu Xinhui,Li Qingxing 2019, 23 (26):  4148-4153.  doi: 10.3969/j.issn.2095-4344.1355 Abstract ( 21 )   PDF (726KB) ( 26 )   Save BACKGROUND: Nano-hydroxyapatite/collagen composites can promote the repair of mandibular defects, but the mechanism is still unclear. OBJECTIVE: To investigate the effect of nano-hydroxyapatite/collagen composites on vascular endothelial growth factors in mandibular defects of domestic pigs. METHODS: Sixty domestic pigs (provided by the Laboratory Animal Center of the First Hospital of Hebei Medical University, China) were randomized into three groups (n=20/group): sham group (no intervention), control group (model of mandibular defect with 10 mm×5 mm×1 mm), and observation group (model of mandibular defect with 10 mm×5 mm×1 mm, and implantation of nano-hydroxyapatite/collagen composite material). At 12 weeks after surgery, the mandibular defect areas were removed for hematoxylin-eosin staining, immunohistochemistry and X-ray examination. The study was approved by the Animal Ethics Committee of the First Hospital of Hebei Medical University. RESULTS AND CONCLUSION: Hematoxylin-eosin staining showed that some materials in the central part of the material in the observation group were degraded, and a large number of metabolically active cells were dispersed in the material cavity, which was surrounded by numerous trabecular bones. The defect area in the control group was covered by fibrous granulation tissue without obvious osteogenesis. The tissues in the mandibular part of sham group arranged regularly. The area of newly born bone in the observation group was significantly larger than that in the control group (P < 0.05). X-ray examination revealed that there was obvious defect in the control group, and the defect area in the observation group was significantly smaller than that in the control group. Immunohistochemistry results indicated that the expression level of vascular endothelial growth factor in the observation group was significantly higher than that in the control group (P < 0.05). In summary, nano-hydroxyapatite/collagen composite can promote the healing of pig mandibular defect, and increase vascular endothelial growth factor level. Figures and Tables | References | Related Articles | Metrics

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Effect of different techniques on the osteogenic property of undecalcified heterogeneous dentin particles Zhao Binbin, Qiu Zewen, Ma Chenghui, Zhong Weijian, Ma Guowu 2019, 23 (26):  4154-4159.  doi: 10.3969/j.issn.2095-4344.1354 Abstract ( 12 )   PDF (23819KB) ( 23 )   Save BACKGROUND: Autologous dentin particles have been shown to possess good biocompatibility and osteoconductivity, which can be used as bone grafting materials, but the biosafety and osteogenic capacity of heterogeneous dentin particles are still unclear. OBJECTIVE: To observe tissue reaction and osteogenic effects of undecalcified heterogeneous human dentin particles processed with different treatment methods and implanted into skull defect of rat model. METHODS: Extracted human teeth were prepared into 0.25-0.5 mm sized dentin particles after washing, pulverizing, boiling, degreasing and sterilization (donors consent to the experiment). Forty healthy adult male Sprague-Dawley rats were selected to create an animal model of skull defect (provided by Laboratory Animal Center of Dalian Medical University), and the cortical skull bone was removed by round bur perforation. The animals were randomly divided into four groups: untreated, boiled treatment, degreased treatment, and boiled plus degreased groups. Specimens were harvested at 4 and 12 weeks after bone grafting, and the degree of inflammatory reaction and bone regeneration effects were evaluated by gross observation, histological examination and histomophometric analysis. This study was approved by the Experimental Animal Ethics Committee of Dalian Medical University, China. RESULTS AND CONCLUSIONS: (1) Gross observation showed that the dentin particles in the four groups were surrounded by fibrous tissue, and the graft was firm and stable. At 12 weeks, the graft was slightly smaller than that at 4 weeks. (2) Histological observation showed that in each group, the fibrous connective tissue was surrounded by dentin particles and inflammatory cell infiltration and a large number of new blood vessels were observed in fibrous connective tissue. Polynuclear macrophages were visible around the dentin particles, and there were worm-like absorption regions at the edge of the particles. Compared with the 4th week, the number of new capillaries around the dentin particles increased at 12 weeks, the number of inflammatory cells decreased, new bone formation was observed around the dentin particles, and it was connected with the skull, and the osteocyte proliferated actively. Histological analysis showed that there were no significant differences in the number of inflammatory cells, neovascularization, macrophage count and new bone formation between the four groups (P > 0.05). (3) These results showed that human dentin granule treated by different methods showed similar inflammatory responses in bone grafting, and good biocompatibility and osteoconductivity in rat skull defect repair. Figures and Tables | References | Related Articles | Metrics

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Effect of hydrothermal treatment on the plasma-sprayed hydroxyapatite coatings Zhao Wen, Liu Feng, Wang Hongfu, Cheng Bo, Wang Junyuan 2019, 23 (26):  4160-4164.  doi: 10.3969/j.issn.2095-4344.1350 Abstract ( 20 )   PDF (687KB) ( 36 )   Save BACKGROUND: Hydroxyapatite coating prepared by plasma spraying on titanium alloy surface has many advantages, such as high flame temperature, fast flight speed, little thermal effect of deposited body, good smoothness, mature technology and high automation, but there are also many problems, such as poor mechanical properties, low crystallinity and large residual stress. OBJECTIVE: To investigate the effects of hydrothermal treatment on the characteristics and mechanical properties of hydroxyapatite coatings. METHODS: Hydroxyapatite coatings were prepared on titanium alloys by plasma spraying. The coatings were hydrothermally treated for 2, 4, 6 and 8 hours respectively. The material characteristics of the coatings before and after hydrothermal treatment were analyzed by scanning electron microscopy, X-ray diffraction and energy dispersive spectrometry. The microhardness and elastic modulus of the coatings were also measured. RESULTS AND DISCUSSION: Hydroxyapatite decomposition and amorphous phenomena occurred during spraying process, resulting in crystalline phases such as TCP, TTCP, CaO and a large number of amorphous phases. Hydrothermal treatment can promote the transformation of crystalline and amorphous phases into crystalline hydroxyapatite. After hydrothermal holding at 150 °C for 8 hours, the crystallinity of the coating increased from 6.9% to 93.76%. More voids and cracks were observed after spraying, which increased the specific surface area of the coating and accelerated the dissolution and recrystallization process of hydroxyapatite. Hydrothermal treatment promoted the formation and aggregation of nano-hydroxyapatite microcrystals on the crack surface, which was the fundamental cause for the phenomenon of "self-healing" of some cracks. The Young’s modulus and micro-hardness of the coating after hydrothermal treatment were better than those after spraying. The results indicate that hydrothermal treatment can effectively improve the crystallinity, elastic modulus and microhardness of hydroxyapatite coatings. Figures and Tables | References | Related Articles | Metrics

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Glass fiber post versus mental post and core for repair of external force-caused dental injury Xiao Yan 2019, 23 (26):  4165-4169.  doi: 10.3969/j.issn.2095-4344.1351 Abstract ( 21 )   PDF (19614KB) ( 41 )   Save BACKGROUND: Glass fiber post or metal post and core are currently used to repair dental injury in the clinic. Both methods can achieve ideal repairing effect.  OBJECTIVE: To investigate the effect of glass fiber post and metal post and core on repairing dental injuries. METHODS: 112 patients with dental injury were selected, including 52 males and 60 females, aged 27-74 years. The patients with odd numbers provided at admission were assigned to the control group (n=56) and received dental repair by metal post and core, and those with even numbers were assigned to the observation group (n=56) and received dental repair with glass fiber post. The incidence of adverse reactions during treatment was recorded, including gingivitis, post and core fracture, crown loosening, gingival staining, post and core loosening. The total effective rate was compared between the two groups 1 week after treatment. The marginal fitness, restoration integrity, and color matching of the two groups were observed at 3 years of follow-up. The levels of periodontal alkaline phosphatase were measured at 3 years of follow-up. This study was approved by the Ethics Committee of Huiji Hospital Affiliated to Hubei Vocational and Technical College of China (approval No. 20150810321) RESULTS AND CONCLUSION: The incidences of gingivitis, post and core fracture, crown loosening, gingival staining, crown or root fracture and post and core loosening in the control group were significantly higher than those in the observation group (control group: 8.9%, 5.3%, 7.1%, 5.3%, 7.1%, 8.9%; observation group: 3.5%, 1.7%, 3.5%, 1.7%, 3.5%, 1.7%, P < 0.05). The total effective rate of dental repair in the control group was significantly lower than that in the observation group (39.29%, 85.7%, P < 0.05). The repair integrity and color matching in the observation group were better than those in the control group (control group: 80.3%, 78.5%; observation group: 98.2%, 94.6%, P < 0.05); and there was no difference in the marginal fitness between the two groups (P > 0.05). In the control group, alkaline phosphatase level was significantly higher after dental repair than that before repair (P < 0.05). In the observation group, alkaline phosphatase level did not change after dental repair compared with before dental repair (P > 0.05). The alkaline phosphatase level in the observation group was significantly lower than that in the control group (P < 0.05). The results suggest that the overall effect of glass fiber post in repairing dental injury was superior to that of metal post and core. Figures and Tables | References | Related Articles | Metrics

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Early versus late reconstruction of anterior cruciate ligament with tendon autografts under arthroscopy Li Shuzhen, Wang Hao, Han Jie, Liang Haibo, Qin Zhi, Sun Ke, Yin Dong 2019, 23 (26):  4170-4174.  doi: 10.3969/j.issn.2095-4344.1352 Abstract ( 21 )   PDF (601KB) ( 34 )   Save BACKGROUND: At present, the surgical timing for repair of acute anterior cruciate ligament injury remains controversial. Some scholars believe that delayed reconstruction will increase joint surface stress and accelerate the degenerative change of the knee joint during long-term motion and suggest early reconstruction of anterior cruciate ligament. Other scholars believe that acute intra-articular hematocele and swelling, inflammatory reaction and joint capsule damage will increase the risk of postoperative knee joint adhesion and stiffness. Therefore, they recommend reconstruction 1 month after injury. OBJECTIVE: To investigate the clinical effects of early versus later anterior cruciate ligament reconstruction. METHODS: Eighty-three patients with anterior cruciate ligament injury, consisting of 48 males and 35 females, who received treatment during January 2014-December 2015 in Ruikang Hospital, Guangxi University of Chinese Medicine, China were included in this study. Among these patients, 37 patients selected autologous hamstring tendon anterior cruciate ligament reconstruction at ≤ 6 weeks after injury (early reconstruction group) and 46 patients selected autologous hamstring tendon anterior cruciate ligament reconstruction at > 6 weeks after surgery (late reconstruction group). After surgery, articular cartilage and meniscus injury were observed under arthroscopy. Joint stability (Lachman test, pivot shift test) and recovery of joint function (hip joint International Knee Documentation Committee score, Lysholm score, limited degree of knee extension and flexion, time spent in recovery of normal range of motion of knee joint) were evaluated. This study was approved by the Ethics Committee of Ruikang Hospital, Guangxi University of Chinese Medicine, China. RESULTS AND CONCLUSION: Cartilage injury occurred in 7 cases in the early reconstruction group and 15 cases in the late reconstruction group. Meniscus injury occurred in 20 cases in the early reconstruction group and 26 cases in the late reconstruction group. There were no significant differences in the incidence, location and severity of cartilage injury between the early reconstruction and late reconstruction groups (P > 0.05). There were no significant differences in the location and incidence of meniscus injury between these two groups (P > 0.05). There were 11 cases of meniscus resection and 9 cases of meniscus suture in the early reconstruction group. There were 22 cases of meniscus resection and 4 cases of meniscus suture in the late reconstruction group. No significant difference was found in Lachman test and pivot shift test results (P > 0.05). There were no significant differences in International Knee Documentation Committee score, Lysholm score and limited degree of knee extension and flexion between early and late construction groups (P > 0.05). The time spent in recovering normal range of motion of knee joint in the late reconstruction group was shorter than that in the early reconstruction group (P < 0.05). These results suggest that early and late anterior cruciate ligament reconstruction can achieve the same clinical effect, but early reconstruction can increase the probability of meniscus healing. Figures and Tables | References | Related Articles | Metrics

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Basic research of tissue engineering in China: Bibliometric analysis Chen Juan, Wu Yidan, Zhang Ting, Yan Shu, Wang Tingting, Yang Yusheng, Ouyang Zhaolian 2019, 23 (26):  4175-4180.  doi: 10.3969/j.issn.2095-4344.1356 Abstract ( 13 )   PDF (657KB) ( 20 )   Save BACKGROUND: The development of tissue engineering is of great social and economic significance. Understanding the current status of basic research in this field can provide reference for developing corresponding development strategies. OBJECTIVE: To evaluate China's basic research current status in the field of tissue engineering. METHODS: A computer-based online search of Pubmed was performed to retrieve basic research papers and top papers in the field of tissue engineering using search terms MESH terms AND free-text word. In the context of global background, China’s ability of basic research in the field of tissue engineering was analyzed based on the number of papers, the growth of the number of papers, the number and proportion of top papers. In addition, the number of papers was used to identify the global research hotspots in the field of tissue engineering. RESULTS AND CONCLUSION: The top five countries in the field of tissue engineering were the United States, China, Japan, Germany and the United Kingdom. The total number of papers in this field published by Chinese scholars reached 17,031, second only to the United States. The compound annual growth rate of the number of papers was 19.9%, and the number of top papers was 195, ranking first and last among the top five countries, respectively. Eight Chinese institutions ranked top 30 in the number of papers in this field, with an average growth rate of 21.2%, far higher than that of all the top 30 institutions in the world (21.2% vs. 14.2, P < 0.001). However, Chinese institutions produced fewer top papers as compared to other top institutions, with the proportion of top papers significantly lower than that of the average level of the top 30 institutions (2.0% vs. 5.2%; P=0.002). There were five Chinese researchers whose total publications entered top 25 of the world. China's research in tissue engineering focuses on the areas of bone and cartilage, nerves, liver, skin, heart and eye tissue engineering, which is consistent with the global status. China's basic research in the field of tissue engineering ranks second in the world and expands rapidly in recent years. A number of academic institutions and individuals with great achievements have emerged. However, China's research quality in this field is relatively low as compared to other top institutions. It is suggested to guide researchers to pay more attention to the quality and transformation of research output, and to support the development of basic subjects such as material science to lay a good foundation for the development of tissue engineering in China. Figures and Tables | References | Related Articles | Metrics

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Treatment of chronic refractory wounds with negative pressure wound therapy and platelet-rich plasma: accelerating the re-epithelialization of wounds and increasing Yang Biao,Wang Shan, Zhang Yan, Liang Chunyu 2019, 23 (26):  4181-4186.  doi: 10.3969/j.issn.2095-4344.1357 Abstract ( 18 )   PDF (785KB) ( 43 )   Save BACKGROUND: Negative pressure wound therapy has been proven to be an effective method to accelerate the healing of various acute and chronic wounds. Platelet-rich plasma is a biotechnology used to stimulate and accelerate tissue healing. OBJECTIVE: To investigate the clinical efficacy of negative pressure wound therapy in combination with platelet-rich plasma versus simple negative pressure wound therapy in the treatment of chronic refractory wounds. METHODS: This study was approved by Ethics Committee of the North China University of Science and Technology Affiliated Hospital, China. All included patients or their legal gardian signed informed consent. Fifty patients with chronic refractory wounds were randomly divided into a control group (n=25) and a combined treatment group (n=25). After surgical debridement, patients in the control group received negative pressure wound therapy. In the combined treatment group, after surgical debridement, platelet-rich plasma gel was used to cover the wounds and then negative pressure wound therapy was performed. The negative pressure values of the two groups were set at -9.31 to -39.9 kPa. The treatment was continued with a suction mode. Dressing was changed once a week. Skin grafting was performed according to the wound healing condition. Bacterial culture results, leukocyte and C-reactive protein levels, and erythrocyte sedimentation rate were recorded before and at 7 and 14 days of treatment. Bacterial negative conversion rate, NRS pain score, time required for the second stage repair operation, wound healing time, and length of hospital stay were compared between combined treatment and control groups. RESULTS AND CONCLUSION: There was no significant difference in the levels of inflammatory factors between the two groups at 7 days after treatment (P > 0.05). The levels of various inflammatory factors, bacterial negative conversion rate and infection control time in the combined treatment group were significantly lower than those in the control group at 14 days after treatment (P < 0.05). The NRS pain score showed a downward trend with treatment time in both groups (P < 0.05). At 14 days after treatment, the NRS pain score in the combined treatment group was significantly lower than that in the control group (P < 0.05). The time required for the second stage repair operation, wound healing time, and length of hospital stay in the combined treatment group were significantly shorter than those in the control group   (P < 0.05). All patients were followed up for 1 to 3 months after discharge. Wounds did not recur during the follow up. These results suggest that negative pressure wound therapy in combination with platelet-rich plasma gel exhibits better antibacterial effects than simple negative pressure wound therapy in the treatment of chronic refractory wounds, can effectively shorten wound bed preparation time and wound healing time, accelerate the re-epithelialization of wounds, increase wound healing rate, and relieve pain in the patients. Figures and Tables | References | Related Articles | Metrics

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Cut-and-sew maze procedure and mitral valve replacement in the treatment of atrial fibrillation associated with giant left atrium and rheumatic mitral valve disease Xie Saiqi, Wang Huishan, Han Jinsong, Yin Zongtao, Han Bing 2019, 23 (26):  4187-4193.  doi: 10.3969/j.issn.2095-4344.1358 Abstract ( 19 )   PDF (734KB) ( 34 )   Save BACKGROUND: The surgical treatment of atrial fibrillation associated with giant left atrium and rheumatic mitral valve disease is still a challenge, because the recurrence rate is high. Cut-and-sew maze procedure is the gold standard for the treatment of atrial fibrillation, but few studies are reported on cut-and-sew procedure used to treat this disease.  OBJECTIVE: To evaluate the safety and efficacy of cut-and-sew maze procedure and mitral valve (mechanical valve and biovalve) replacement in the treatment of atrial fibrillation associated with giant left atrium and rheumatic mitral valve disease. METHODS: Patients with atrial fibrillation associated with rheumatic mitral valve disease who underwent the cut-and-sew maze procedure and mitral valve replacement in our hospital during April 2014 to October 2017 were retrospectively analyzed; 114 patients were enrolled according to the inclusion and exclusion criteria. By defining 60 mm as the boundary of the left atrial dimension, patients were divided into a non-giant left atrium group (left atrial dimension < 60 mm, n=85) and a giant left atrium group (left atrial dimension ≥ 60 mm, n=29). Perioperative safety indexes and postoperative curative effect were compared between the two groups. This study was approved by the Ethics Committee of General Hospital of Northern Theater Command (formerly General Hospital of Shenyang Military Region), China (approval No. lunshen-k(2015)33). RESULTS AND CONCLUSION: Intraoperative safety indexes: There were no significant differences in the time of aortic occlusion, intraoperative cardiopulmonary bypass, intraoperative blood loss, operation duration and mitral valve replacement type between the two groups (P > 0.05). Postoperative safety indexes: There were no significant differences in the proportion of secondary thoracotomy after surgery, proportion of electrical cardioversion and temporary pacemaker applications, the time of ventilator use, ICU stay, length of hospitalization, early postoperative drainage volume and the incidence of early postoperative compilations between non-giant left atrium and giant left atrium groups (P > 0.05). Postoperative efficacy analysis: there was no significant difference in the recovery rate of sinus rhythm between non-giant left atrium and giant left atrium groups on the day of surgery, at discharge, and 6 months and 1 year after surgery (P > 0.05). There was no significant difference in cardiac function recovery between non-giant left atrium and giant left atrium groups at 6 months and 1 year after surgery (P > 0.05). These results suggest that cut-and-sew maze procedure and mitral valve replacement for the treatment of atrial fibrillation associated with giant left atrium and rheumatic mitral valve disease are highly safe and exhibit encouraging short-term efficacy. Figures and Tables | References | Related Articles | Metrics

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Inhibitory effects of doxorubicin-loaded chitosan nanoparticles on osteosarcoma in mice Li Yongheng, Cui Yan, Zhang Zhiyu 2019, 23 (26):  4194-4199.  doi: 10.3969/j.issn.2095-4344.1359 Abstract ( 20 )   PDF (802KB) ( 42 )   Save BACKGROUND: A large number of recent studies have shown that the nanocarrier system can achieve drug release or activation in tumor tissues, increase local drug concentration, reduce drug accumulation in normal tissues, and reduce adverse reactions. OBJECTIVE: To analyze the cytotoxicity of doxorubicin-loaded chitosan nanoparticles and their inhibitory effect on osteosarcoma. METHODS: Cytotoxicity tests: Murine osteosarcoma cell line K7 was interfered with PBS containing doxorubicin-loaded chitosan nanoparticles (referred to as drug-loaded nanoparticles) and PBS containing free doxorubicin (doxorubicin concentrations 0.16, 0.31, 0.62, 1.25, 2.5, 5,10 mg/L) for 24 and 72 hours. Cell viability was measured by MTT assay. In vivo drug distribution test: Balb/c mouse (Changchun Institute of Biological Product Co., Ltd., China) models of tumor were established by subcutaneous injection of murine osteosarcoma cell line K7. When tumor volume reached 200 mm3, mice in the experimental and control groups were respectively injected with PBS containing doxorubicin-loaded nanoparticles and PBS containing free doxorubicin via the tail vein. The mice were sacrificed at 6 and 12 hours after drug administration and the fluorescence of doxorubicin in various organs was observed. In vivo tumor growth inhibition test: Balb/c mouse models of tumor were established by subcutaneous injection of murine osteosarcoma cell line K7. When tumor volume reached 50 mm3, mice in the experimental and control groups were respectively injected with PBS containing doxorubicin-loaded nanoparticles and PBS containing free doxorubicin via the tail vein. PBS was injected in the blank control group, once every 4 days, for a total of 6 times. Mouse body mass and tumor volume were daily measured. Animal experiments were approved by Animal Ethics Committee of Jilin University, China. RESULTS AND CONCLUSION: The median lethal concentration of doxorubicin-loaded nanoparticles and free doxorubicin was 2.4 and 4.2 mg/L respectively at 24 hours after drug application, and it was 0.29 and 0.91 mg/L respectively at 72 hours after drug application. Doxorubicin-loaded nanoparticles mainly accumulated in the liver, kidney, and tumor. During the treatment period, average tumor volume in the experimental group was significantly smaller than that in the control and blank control groups (P < 0.001). The average mouse body mass in the experimental group was significantly greater than that in the control group (P < 0.001). The results show that the drug-loaded system can well control in vivo release of doxorubicin and greatly enhance the inhibitory capacity of chemotherapy drugs against osteosarcoma. Figures and Tables | References | Related Articles | Metrics

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Preparation of chitosan/isoliquiritigenin nanoparticles and their inhibitory effects on the proliferation of human lung cancer cell line A549 Lü Wenjuan, Liu Fuding, Wang Taojiao, Wan Lang, Chen Fang 2019, 23 (26):  4200-4205.  doi: 10.3969/j.issn.2095-4344.1360 Abstract ( 17 )   PDF (696KB) ( 33 )   Save BACKGROUND: Isoliquiritigenin, one kind of isoflavone compounds, has a wide range of biological activities, such as anti-cancer, anti-virus, and anti-diabetes, but its clinical application is limited by its poor water solubility. OBJECTIVE: To prepare chitosan/isoliquiritigenin nanoparticles and investigate their inhibitory effects on human lung cancer cell line A549 in vitro. METHODS: The chitosan/isoliquiritigenin nanoparticles were prepared by ionic gelation method with chitosan as the carrier material, isoliquiritigenin as the model drug, and sodium tripolyphosphate as the ionic crosslinking agent. The nanoparticle size, dispersion, and Zeta potential were investigated by malvern laser particle size analyzer. The morphology of the nanoparticles was observed by transmission electron microscopy. The encapsulation efficiency and cumulative release rate of the nanoparticles were measured by centrifugation. Isoliquiritigenin and chitosan/isoliquiritigenin nanoparticles were placed in dialysis bags and their dynamic release was determined in PBS buffer. Human lung cancer cell line A549 was cultured in different concentrations (1, 5, 25 mg/L) of isoliquiritigenin, chitosan/isoliquiritigenin nanoparticles, and chitosan nanoparticles. MTT assay was used to investigate the inhibitory effects of chitosan/isoliquiritigenin nanoparticles on human lung cancer cell A549 in vitro after 48 hours of culture. The growth-inhibitory rate was calculated. RESULTS AND CONCLUSION: The chitosan/isoliquiritigenin nanoparticles were spherical or quasi spherical in shape with complete structure and of relatively uniform size. The average particle size, dispersion and Zeta potential of chitosan/isoliquiritigenin nanoparticles were (159±20) nm, 0.243 and +17.2 mV, respectively. The encapsulation efficiency and cumulative release rate of the nanoparticles were (85.28±1.31)% and (13.28±0.53)% respectively.The release of free isoliquiritigenin was completed within 8 hours, while the chitosan/isoliquiritigenin nanoparticles had sustained release property in vitro, with 72-hour cumulative release amount of 83.98%. This well fitted the first-order kinetic model. Chitosan nanoparticles at different concentrations had no inhibitory effects on the growth of A549 cells. Both isoliquiritigenin and chitosan/isoliquiritigenin nanoparticles inhibited the growth of A549 cells in a concentration-dependent manner, and the inhibitory effect of chitosan/isoliquiritigenin nanoparticles was stronger than that of isoliquiritigenin when used at the same concentration    (P < 0.05). The results suggest that the chitosan/isoliquiritigenin nanoparticles prepared by ionic crosslinking method had encouraging sustained release performance and enhanced the inhibitory effects of isoliquiritigenin on the proliferation of A549 cells in vitro. Figures and Tables | References | Related Articles | Metrics

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Biocompatibility of modified chemically cross-linked acellular dermal matrix Li Lihua, Xiong Jian, Cao Ping, Zhong Meiling, Zhu Yongjun, Xu Weiqu, Kang Wenting, She Zhending, Tan Rongwei 2019, 23 (26):  4206-4211.  doi: 10.3969/j.issn.2095-4344.1361 Abstract ( 19 )   PDF (767KB) ( 40 )   Save BACKGROUND: Acellular dermal matrix has the disadvantages of natural materials such as rapid and unregulated degradation and poor mechanical properties. It is a commonly used improvement measure for glutaraldehyde cross-linking modification. However, glutaraldehyde itself has a high cytotoxicity, which affects the biocompatibility of acellular dermal matrix. OBJECTIVE: To improve the biocompatibility of the glutaraldehyde cross-linked acellular dermal matrix by using glycine to neutralize remaining aldehyde groups. METHODS: As an experimental group, the acellular porcine dermal matrix was cross-linked by glutaraldehyde and then neutralized by glycine. The control group was that acellular dermal matrix which was cross-linked by glutaraldehyde but not neutralized by glycine. The residual exogenous DNA of materials of the experimental group was detected by DNA kit. The uncrosslinked acellular porcine dermal matrix and the samples of the experimental group and control group were immersed in collagenase solution to observe degradation performance. Mouse fibroblasts were cultured in culture medium, high-density polyethylene extracts, sample extracts of the experimental group and control group, respectively. After 24 hours of culture, cell proliferation rate was determined by MTT assay. Mouse osteoblasts were seeded onto the membrane surface of the experimental group and the control group and cultured for 7 days. The cell status was observed under confocal microscope. The membrane materials of the experimental group and the control group were respectively implanted beneath the skin of New Zealand rabbits, and the samples with surrounding tissues were removed at 2 weeks later for hematoxylin-eosin staining observation. RESULTS AND CONCLUSION: (1) The amount of DNA residues in samples of the experimental group was (3.12±0.7) µg/g. (2) After enzymolysis for 8 hours, there was no significant difference in the weight loss rate of samples between the experimental group and the control group (18%-21%), while the weight loss rate of samples without glutaraldehyde cross-linking was 100%. (3) After culture for 24 hours, the proliferation rates of fibroblasts cultured in the leaching liquor of samples in the experimental and the control groups were 98.1% and 91.3%, respectively. The results showed the level of cytotoxicity was both grade 1. (4) Osteoblasts spread evenly and multiplied vigorously on the membrane surface in the experimental group, while curled up and were few in number in the control group. (5) After membranes implanted beneath the skin of the rabbit for 2 weeks, tissues around the implant site of the experimental group showed a slight inflammatory response, while those in the control group showed severe inflammatory response. (6) These results suggest that glycine neutralizing remaining aldehyde groups could improve the biocompatibility of glutaraldehyde cross-linked acellular dermal matrix material on the premise of guaranteeing the degradation performance. Figures and Tables | References | Related Articles | Metrics

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Ozone oxidation of the surface of artificial ligament material polyethylene terephthalate fiber Shi Fengtian, Zhang Mei, Sun Shichao, Chen Shuxiang, Li Dengyun, Sun Xuelian 2019, 23 (26):  4212-4216.  doi: 10.3969/j.issn.2095-4344.1362 Abstract ( 708 )   PDF (696KB) ( 108 )   Save BACKGROUND: Artificial ligament material polyethylene terephthalate fiber has good physical-chemical- mechanical properties, but its surface affinity is poor, and it does not have good cell compatibility. Therefore, it is necessary to modify the surface of the material. OBJECTIVE: This study was designed to form active sites on the surface of polyethylene terephthalate fiber by ozone oxidation, and to improve its cell compatibility. METHODS: The polyethylene terephthalate fiber was braided into a grey fabric by warp knitting and cut into small cuts at suitable sizes. The small cuts were placed in distilled water for 30-minute ozone oxidation at room temperature with oxygen flow rate of 1 L/min and ozone concentration in aqueous solution of 10 mg/L. The surface morphology, mechanical properties, and toluidine blue adsorption of polyethylene terephthalate fiber were observed before and after ozone oxidation. RESULTS AND CONCLUSION: Scanning electron microscopy showed that the surface roughness of polyethylene terephthalate fiber increased slightly after ozone oxidation, and there was no obvious evidence of cracking degradation. After ozone oxidation, peroxy groups were successfully introduced onto the surface of polyethylene terephthalate fiber with a concentration of 10-5 mol/g. After ozone oxidation, the surface of the polyethylene terephthalate fiber did not show obvious degradation, and the mechanical property remained good. It can meet the requirement of the tensile properties of the artificial ligament material. Before ozone oxidation, the polyethylene terephthalate fiber lacked hydrophilic groups in the main chain, and hardly adsorbed toluidine blue. After ozone oxidation, toluidine blue absorption increased with the increase of hydrophilic groups on the surface of the fiber. All results suggest that ozone oxidation treatment not only ensures the mechanical property of polyethylene terephthalate fiber, but also introduces a sufficient amount of peroxy groups on its surface. Figures and Tables | References | Related Articles | Metrics

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Bionic polylactic acid/gelatin nanofiber membrane for repairing varicose ulcers in the lower extremities  Chen Hongrang, Shen Yun, Zhang Haitao, Deng Kunxue, Xu Yuanling, Dai Xingliang, Li Yongsheng, Zhang Xinqiong, Xu Tao 2019, 23 (26):  4217-4224.  doi: 10.3969/j.issn.2095-4344.1363 Abstract ( 14 )   PDF (916KB) ( 29 )   Save BACKGROUND: Insufficient effective treatments lead to protracted course and recurrence of lower extremity venous ulcers, greatly influencing patient’s life. Animal experiments have confirmed that bionic polylactic acid/gelatin nanofiber membrane has advantages in the repair of deficient skin tissue. OBJECTIVE: To investigate the efficacy of bionic polylactic acid/gelatin nanofiber membrane in the repair of varicose ulcers in the lower extremities. METHODS: Sixty patients with varicose ulcers in the lower extremities admitted to the First Affiliated Hospital of Anhui Medical University, China from November 2017 to November 2018 were randomly divided into a control group and an experimental group, with 30 cases in each group. All patients were given debridement and basic treatment in the early stage. Patients in the control group received conventional dressing. Patients in the experimental group received bionic polylactic acid/gelatin nanofiber membrane dressing based on conventional dressing. Wound healing rate, healing time, dressing change frequency, wound pain average score, dressing-caused secondary wound score, ease of operation, safety and patient satisfaction were recorded and compared between the two groups every week. At 6 months after wound healing, post-repair effect was evaluated using the Vancouver Scar Rating Scale. This study was approved by the Ethics Committee, First Affiliated Hospital of Anhui Medical University, China (approval No. PJ2018-01-09). RESULTS AND CONCLUSION: At 28 days after dressing, wound healing rate and patient satisfaction in the experimental group were significantly greater than those in the control group (P < 0.05). Healing time, dressing change frequency, wound pain average score, dressing-caused secondary wound score, and ease of operation in the experimental group were significantly lower than those in the control group (P < 0.05). Six months after wound healing, scale score in the control group was significantly higher than that in the experimental group (P < 0.05). During dressing and 6 months after wound healing, there were no liver and kidney injuries in the two groups. In addition, no reverse reactions such as local allergy were observed in either group. These results suggest that bionic polylactic acid/gelatin nanofiber membrane for repairing ulcers in patients with lower extremity varicose veins is safe and effective. It can greatly shorten the wound healing time, reduce dressing change frequency, mitigate pain and secondary trauma during wound dressing change, and provide the ease of use by clinical medical staff, and improve patient comfort and satisfaction. Figures and Tables | References | Related Articles | Metrics

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Construction and support force of micro-stent by multi-directional stretching Han Bensong, Xue Feng, Mo Xiumei 2019, 23 (26):  4225-4229.  doi: 10.3969/j.issn.2095-4344.1364 Abstract ( 11 )   PDF (17721KB) ( 26 )   Save BACKGROUND: Polylactic acid is a kind of biodegradable macromolecule material with good properties, which is widely used in cardiovascular stents, and internal fixation nail-plate. By stretching amorphous polylactic acid, chain orientation and crystalline structure can be obtained, and its mechanical properties are improved. OBJECTIVE: To investigate the feasibility of multi-directional stretching for the preparation of polylactic acid micro-stents. METHODS: The ring-shaped stent base rod was made by polylactic acid with a molecular weight of 100 kDa. The multi-directional hot stretching was carried out in a self-made drafter. The draw ratio was 0, 0.5, 1, 1.5, 2, and 2.5, respectively. After the stents were stretched and formed, the radical strength was detected by tension method and the longitudinal section of base rod of the stent was observed by scanning electron microscope. RESULTS AND CONCLUSION: (1) Two micro-frames with diameters of 0.5 mm (group A) and 1 mm (group B) were prepared. The diameter of the base rod was 0.08-0.1 mm, and the length was 6 mm. (2) Stretching process could significantly improve the radial support performance of polylactic acid micro-stent, the radial support force increased with the increase of the draw ratio, which reached the maximum at a draw ratio of 2, then the support force decreased. (3) Scanning electron microscope showed that when the stretching ratio was 0, and 0.5, the internal unit structure of the base rod arranged more tightly and regularly, and gradually arranged along the axial direction of the base rod; when the stretching ratio was 1, the structural unit exhibited a lateral bending orientation, but wrinkles were uneven. When the stretching ratio was 1.5 and 2, the bending orientation was further enhanced, and the compact structure was restored under the new structure arrangement. When the stretching ratio was 2.5, the structural unit was rough and the microstructure was unevenly broken. (4) These results suggest that micro-stent can be formed by multi-directional stretch, and the stretching ratio can obviously affect the stent performance. The orientation of the stent is obviously improved. The higher the stretching ratio, the stronger the radial support force, and the more reliable support strength of small vessel repair. Figures and Tables | References | Related Articles | Metrics

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Preparation of sodium alginate-hydroxyapatite-polyethylene glycol composite hydrogel scaffold and its biocompatibility Li Xuanze, Shu Liping, Chen Jiao, Sun Yu, Zou Qiang, Wang Weiyu, Liu Jun, Yang Long, Ma Minxian, Ye Chuan 2019, 23 (26):  4230-4236.  doi: 10.3969/j.issn.2095-4344.1365 Abstract ( 401 )   PDF (846KB) ( 234 )   Save BACKGROUND: Polyethylene glycol, as a medical polymer copolymer, is widely used in sustained-release of drugs. If it is prepared into composite hydrogel, it can be used as a scaffold material with certain mechanical properties and good biocompatibility. OBJECTIVE: To investigate the physical and chemical properties and biocompatibility of sodium alginate-hydroxyapatite-polyethylene glycol (SA-HA-PEG) composite hydrogel scaffold material. METHODS: Bivalent cationic solution was added to the ultrasound treated hydrogel for crosslinking. Four groups of scaffold were obtained: SA-HA scaffold (group A), SA-HA-3%PEG (group B), SA-HA-5%PEG (group C), SA-HA-8%PEG (group D). The mass concentration of PEG in the later three groups was 30, 50, and 80 g/L. The compressive stress and elastic modulus of the hydrogel scaffold were analyzed using a dynamic mechanical analyzer. The scaffold was placed in lysozyme solution to determine its degradation rate in vitro. After vacuum freeze-drying, the three-dimensional structure of the hydrogel scaffold was observed by scanning electron microscopy. Four groups of hydrogel scaffold were cross-linked with bone marrow mesenchymal stem cells. Cell proliferation was detected using CCK8 assay at 1, 3, 5 and 7 days of culture. After 7 days of culture, cell viability was detected using Live/Dead fluorescence staining. RESULTS AND CONCLUSION: The compressive stress and elastic modulus in the groups B, C and D were significantly higher than those in the group A (P < 0.05). The compressive stress and elastic modulus in the groups C and D were significantly higher than those in the group B (P < 0.05). There were no significant differences in compressive stress and elastic modulus between groups C and D (P > 0.05). The degradation rate of hydrogel scaffold in the groups C and D were significantly lower than that in the groups A and B (P < 0.05). The degradation rate of hydrogel scaffold in the group B was significantly lower than that in the group A (P < 0.05). There was no significant difference in the degradation rate of hydrogel scaffold between groups C and D (P > 0.05). Scanning electron microscopy showed that hydrogel scaffold in the group C had the structure with high porosity and consistent pore size; hydrogel scaffold in the groups A, B and D had the structure with low porosity and inconsistent pore size. After 3-7 days of culture, cells in the groups B, C and D proliferated more rapidly than those in the group A (P < 0.05). There was no significant difference in cell proliferation rate between groups B, C and D (P < 0.05). After 7 days of culture, cell viability in the groups B, C and D was significantly higher than that in the group A (P < 0.05), and cell viability in the group C was significantly higher than that in the groups B and D (P < 0.05). These results suggest that SA-HA-PEG composite hydrogel scaffold exhibit good mechanical property and encouraging biocompatibility.   Figures and Tables | References | Related Articles | Metrics

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Basic and clinical research progress of autologous skull as a material for cranioplasty Yan Ke, Lu Lichun, Zhao Haifeng, Wang Weihua, Zhu Wenyu, Huang Qiang 2019, 23 (26):  4237-4242.  doi: 10.3969/j.issn.2095-4344.1366 Abstract ( 18 )   PDF (35664KB) ( 32 )   Save BACKGROUND: During cranioplasty, skull autografts have irreplaceable advantages because of its homology and low cost. However, skull autografts have not be preferred and tend to be substituted by 3D titanium mesh because they can be absorbed after re-implantation. OBJECTIVE: To summarize the recent advances in re-implantation of skull autografts in clinical and animal experiments and the possible mechanisms underlying absorption of skull autugrafts. METHODS: Clinical and animal studies related to cranioplasty with skull autografts published during January 1990-January 2019 in PubMed, China Biomedical Literature Database (CBMdisc), Wanfang Database and CNKI were retrieved. RESULTS AND CONCLUSION: Clinically, the infection rate and absorption rate after re-implantation of skull autografts were more frequently reported. The direct causes of low success rate of complete graft are imperfect temperature and sterilization condition for preserving bone flaps. Animal experiments were mainly to explore the bone resorption and osteogenesis mechanism of small and medium-sized animals. Little is reported on the simulation of delayed autologous skull formation after large-scale craniotomy. In the context of absorbing and nascent coexistence in all re-implanted bone grafts, there was always a gap between the bone flap and the bone window edge in patients undergoing phase I reduction in craniotomy. The authors found that the flat skull and the long bone of the extremities have different mechanisms in osteoinduction and bone conduction, and isolated bone flaps containing periosteum and dura mater should be preserved for creating optimal resuscitation conditions, like organ transplantation. This will be addressed in future work. Figures and Tables | References | Related Articles | Metrics

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Research progress and clinical application of nano-fat Yi Xiaolin, Liang Zhijie, Li Hongmian 2019, 23 (26):  4243-4248.  doi: 10.3969/j.issn.2095-4344.1367 Abstract ( 13 )   PDF (36698KB) ( 29 )   Save BACKGROUND: In recent years, there is an increasing area of nano-fat and its clinical application. OBJECTIVE: To summarize the research progress and clinical application of nano-fat. METHODS: A computer-based online search of China Academic Journals Full-text Database, Wanfang database, VIP Chinese Technology Periodical Database, Pubmed database was performed to retrieve documents regarding nano-fat and adipose-derived stem cells with the search terms “nanofat, adipose-derived stem cells, fat grafting” in Chinese and English. Fifty-two publications were included in the final analysis. RESULTS AND CONCLUSION: The retrieved documents have demonstrated that nano-fat exhibits obvious effects in preventing against age and scar and on would repair and filling. However, sample size is small. A larger number of studies are required to support this conclusion. The currently prepared nano-fat contains multiple components. In-depth studies are required to investigate the precise mechanisms of action. There are no unified criteria to prepare nano-fat. Many links such as selection of fat source, method of sucking fat, mechanical emulsification and filtration of fat, and nursing after nano-fat transplantation should be further improved. Figures and Tables | References | Related Articles | Metrics

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Biological cage in intervertebral bone integration: histocytological properties of interface and healing mechanism of osseointegration Jia Peng, Zhang Tao 2019, 23 (26):  4249-4254.  doi: 10.3969/j.issn.2095-4344.1368 Abstract ( 7 )   PDF (35557KB) ( 27 )   Save BACKGROUND: Biological cage has been widely used in the fields of spinal orthopedics, nanometer materials and bionic biomedicine as the substitutes of new bone repair materials due to its high mechanical properties and biocompatibility. However, its effects remain controversial. OBJECTIVE: To summarize and discuss the current design conception, biomechanical characteristics, degradation properties, basic and clinical research of biological cage, so as to provide basis for clinical application of biological cage. METHODS: CNKI, WanFang and PubMed databases were retrieved with the key words “biological cage, biocompatibility, degradation properties, mechanical properties” in Chinese and English, respectively. The preparation, mechanics, degradation characteristics and experiments of biological cage were summarized RESULTS AND CONCLUSION: One hundred and thirty-two articles were retrieved and 48 eligible articles were included according to inclusion and exclusion criteria. The combination of biphasic or mutiphase materials has become the mainstream of cage design, and tissue engineering and surface modification have effectively promoted the intervertebral fusion. At present, the main drawbacks are the mechanical instability and aseptic inflammation caused by its own degradability which still needs to be further explored. The biological cage based on polylactic acid and β-tricalcium phosphate can complement each other. This copolymer can simultaneously meet the mechanical properties and biocompatibility during the fusion. What needs attention is that the curvature of cage, place position and matching degree with the upper and lower endplates are important factors affecting the intervertebral bone integration. However, the concrete mechanism of osteointegration remains unclear. The gene expression of the cytokines, the signaling pathway, the effect of the cage on the bone repairing cell proliferation and aseptic cage loosening need further exploration. Figures and Tables | References | Related Articles | Metrics

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Research status and prospects of tissue engineering technology for repairing intervertebral disc annulus fibrosus Wang Shuang, Yu Lei, He Yunfei, Ma Jun, Wen Jiankun, Ye Xiaojian 2019, 23 (26):  4255-4259.  doi: 10.3969/j.issn.2095-4344.1369 Abstract ( 503 )   PDF (28303KB) ( 371 )   Save BACKGROUND: The repair of annulus fibrosus of intervertebral disc plays an important role in the prognosis of spine surgery, but there is no ideal repair method at present. The rapid development of tissue engineering technology in recent years is expected to solve this problem. By constructing scaffold-cell complex, the annulus fibrosus and its adjacent intervertebral discs can regenerate and grow at the same time, so as to achieve the purpose of biological repair. OBJECTIVE: To review the research status of repairing of annulus fibrosus, especially the tissue engineering technology applying in this field, and prospect the development of the repairing technology in the future. METHODS: We searched the databases of PubMed and Web of Science with the keywords “Annulus fibrosus; Tissue engineering; Annulus fibrosus; Mesenchymal stem cells”. RESULTS AND CONCLUSION: There are several achievements in the repair of annulus fibrosus using tissue engineering technology. The compound scaffolds with ideal structure can be obtained, in which stem cells can adhere, proliferate and differentiate well. Nevertheless, the determinate molecular mechanisms are not completely clear. The definite functions of cytokines in the proliferation and differentiation of stem cells remain to be further clarified. Tissue engineering has a good application prospect in the field of annulus fibrosus repair. Further research may focus on the scaffold topology, signaling pathways, and non-coding RNA. The research may strive to further elucidate the mechanism of the differentiation of stem cells on different scaffolds and make the scaffolds more suitable for the application of the repair of annulus fibrosus. Figures and Tables | References | Related Articles | Metrics

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Soft silicone foam dressing for the treatment of radiation dermatitis: a meta-analysis Shen Qian, Qiu Wenbo, Hu Peixin, Li Chun, Zhou Chunjiao, Chen Juan 2019, 23 (26):  4260-4264.  doi: 10.3969/j.issn.2095-4344.1303 Abstract ( 27 )   PDF (18019KB) ( 32 )   Save BACKGROUND: Soft silicone foam dressing is made up of 3 layers: soft silicone wound contact layer, polyurethane foam absorbing layer and breathable and waterproof outer covering film. It not only facilitates granulation tissue growth, but also provides a good wet environment for wound healing. OBJECTIVE: To evaluate the efficacy of soft silicone foam dressing in the treatment of radiation dermatitis. METHODS: Randomized controlled trials regarding soft silicone foam dressing applied to radiation dermatitis were searched by computer in PubMed, EMBASE, Cochrane, China Academic Journals Full-text Database, Chinese Biomedical Literature Database, Wanfang database and Chinese Science and Technology Periodicals Database.The retrieval time was limited to the period from database foundation to October 2018. Literature screening, quality evaluation and data extraction were conducted independently by two postgraduates. Revman 5.3 software was used for data analysis. RESULTS AND CONCLUSION: Six Chinese literatures were included, including 416 patients with radiation dermatitis. The experimental group was treated with soft silicone foam dressing, while the control group was treated with traditional dressing, moist exposed burn ointment or lanolin ointment. Meta-analysis results showed that the healing time of radiation dermatitis in the experimental group was shorter than that in the control group [MD=-6.36, 95%CI (-8.72, -4.00), Z=5.28, P < 0.000 01]. The healing rate of radiation dermatitis in the experimental group was significantly higher than that in the control group [OR=5.67, 95%CI (1.74, 18.41), Z=2.89, P=0.004]. The results suggest that soft silicone foam dressing exhibits better therapeutic effects on radiation dermatitis than other dressings. Figures and Tables | References | Related Articles | Metrics