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    18 November 2016, Volume 20 Issue 47 Previous Issue    Next Issue
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    Construction and characteristics of poly(lactic-co-glycolic acid)/calcium silicate scaffolds with three-dimensional pores for bone tissue engineering
    Hu Lu, Wei Kun, Zou Fen
    2016, 20 (47):  6887-7005.  doi: 10.3969/j.issn.2095-4344.2016.47.001
    Abstract ( 291 )   PDF (1748KB) ( 222 )   Save

    BACKGROUND: Some disadvantages exsist in commonly used poly(lactic-co-glycolic acid) (PLGA) scaffolds, including acidic degradation products, suboptimal mechanical properties, low pore size, poor porosity and pore connectivity rate and uncontrollable shape.
    OBJECTIVE: To construct a scaffold with three-dimensional (3D) pores by adding calcium silicate to improve the properties of PLGA, and then detect its degradability, mechanical properties and biocompatibility.
    METHODS: PLGA/calcium silicate porous composite microspheres were prepared by the emulsion-solvent evaporation method, and PLGA 3D porous scaffold was established by 3D-Bioplotter, and then PLGA/calcium silicate composite porous scaffolds were constructed by combining the microspheres with the scaffold using low temperature fusion technology. The compositions, morphology and degradability of the PLGA/calcium silicate porous composite microspheres and PLGA microspheres, as well as the morphology, pore properties and compression strength of the PLGA 3D scaffolds and PLGA/calcium silicate composite porous scaffolds were measured, respectively. Mouse bone marrow mesenchymal stem cells were respectively cultivated in the extracts of PLGA/calcium silicate porous composite microspheres and PLGA microspheres, and then were respectively seeded onto the PLGA 3D scaffolds and PLGA/calcium silicate composite porous scaffolds. Thereafter, the cell proliferation activity was detected at 1, 3 and 5 days.
    RESULTS AND CONCLUSION: Regular pores on the PLGA microspheres and internal cavities were formed, and the PH values of the degradation products were improved after adding calcium silicate. The fiber diameter, pore, porosity and average pore size of the composite porous scaffolds were all smaller than those of the PLGA scaffolds. The compression strength and elasticity modulus of the composite porous scaffolds were both higher than those of the PLGA scaffolds (P < 0.05). Bone marrow mesenchymal stem cells grew well in above microsphere extracts and scaffolds. These results indicate that PLGA/calcium silicate composite porous scaffolds exhibit good degradability in vitro, mechanical properties and biocompatibility.

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    Tissue-engineered periosteum-coated biphasic calcium phosphate scaffold repairs bone defects in rabbits
    Xing Fei, Peng Jing, Chen Long, Peng Kun, Li Lang, Xiang Zhou
    2016, 20 (47):  7006-7013.  doi: 10.3969/j.issn.2095-4344.2016.47.002
    Abstract ( 285 )   PDF (5914KB) ( 225 )   Save

    BACKGROUND: Periosteum has been shown to play an important role in bone defect repair, but large bone defects are often accompanied by the loss of periosteum. Therefore, tissue-engineered periosteum constructed by tissue engineering technology is attracting more attention.
    OBJECTIVE: To investigate the effect of the tissue-engineered periosteum which is constructed by mesenchymal stem cells from the peripheral blood and procine small intestinal submucosa and biphasic calcium phosphates on the repair of bone defects in rabbits.
    METHODS: Mesenchymal stem cells from peripheral blood were seeded onto the procine small intestinal submucosa to construct the tissue-engineered periosteum, and then the cell growth was observed through live/dead staining. The bone defect model of 15 mm in length in the left ulna was created in the 30 healthy New Zealand rabbits, followed by randomly assigned to 3 groups, and then treated with biphasic calcium phosphates and tissue-engineered periosteum-coated biphasic calcium phosphates, respectively. The remaining rabbits received no treatment as controls. Therapeutic effects were compared by X-ray and histological examinations among groups.
    RESULTS AND CONCLUSION: Live/dead staining found that the mesenchymal stem cells grew well and the cell number increased gradually. X-ray Lane-Sandhu scores of the group treated with tissue-engineered periosteum-coated biphasic calcium phosphates were highest, followed by the biphasic calcium phosphates group and the control group at postoperative 4 and 8 weeks (P < 0.05). Histological examination showed that the group treated with tissue-engineered periosteum-coated biphasic calcium phosphates had more osteoblasts, compared with the other two groups. In conclusion, the biphasic calcium phosphate scaffold coated by the tissue-engineered periosteum that is constructed by mesenchymal stem cells from peripheral blood and procine small intestinal submucosa is feasible to repair bone defects. 

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    Biological property of a novel bone cement composited by quaternary ammonium salt chitosan nanoparticles
    He Qiang, Ma Jian-bing, Sun Xiang-xiang, Zhao Guang-hui
    2016, 20 (47):  7014-7020.  doi: 10.3969/j.issn.2095-4344.2016.47.003
    Abstract ( 354 )   PDF (4667KB) ( 252 )   Save

    BACKGROUND: Postoperative infection in patients underlying total knee arthroplasty is a long-standing puzzle. Current bone cement with antibiotics cannot effectively treat kidney function deficiency and bacterial resistance.
    OBJECTIVE: To develop a novel kind of bone cement prepared by quaternary ammonium salt chitosan nanoparticles.
    METHODS: There were three groups including QCSNP-15, Palacos R and Palacos R+G groups. Morphology of the bone cement in each group was observed using scanning electron microscope, the setting time of bone cement was measured, and the in vitro compression strength, cytotoxicity and antibacterial activity tests were performed.
    RESULTS AND CONCLUSION: Scanning electron microscope observed that QCSNP-15 was made of quaternary ammonium salt chitosan nanoparticles and methyl methacrylate copolymer, and these nanoparticles distributed onto the material surface. The setting time of QCSNP-15 was longer than that of the Palacos R+G bone cement. The compressive strength of QCSNP-15 was significantly lower than that of the Palacos R bone cement (P < 0.05), but was larger than 70 MPa stipulated by ISO 5833. Osteoblasts MC3T3-E1adhered well on the QCSNP-15, and pseudopodia fully expanded. Similar findings were observed on the Palacos R+G bone cement. The attachment rate of osteoblasts of the QCSNP-15 at 3 hours was significantly lower than that of the Palacos R+G bone cement (P < 0.05). The antibacterial activity did not significantly differ between QCSNP-15 and Palacos R+G bone cements, even after 2-week immersion in the PBS. These findings suggest that QCSNP-15 exhibits appropriate setting time, good biomechanical property and antibacterial activity in vitro with no obvious cytotoxicity.

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    Polyethylene glycol-modified chitosan nanoparticles loaded with angiotensin converting enzyme-shRNA for hypertension
    Wang Yong, Zhang Ya-guang
    2016, 20 (47):  7021-7026.  doi: 10.3969/j.issn.2095-4344.2016.47.004
    Abstract ( 331 )   PDF (4358KB) ( 217 )   Save

    BACKGROUND: Traditional antihypertensive drugs always have a short half-life period, and show unsatisfactory treatment outcomes. Chitosan, as a gene vector, can carry target genes into the designated location. Polyethylene glycol (PEG) combined with DNA to form the nanoparticles, which can provide surface protection, stabilize the nanoparticles and lengthen the nanoparticle’s half-life.
    OBJECTIVE: To investigate the antihypertensive effect and the histological changes of heart after PEG-modified chitosan nanoparticles loaded with angiotensin converting enzyme (ACE)-shRNA injected into the rat models of spontaneous hypertension.
    METHODS: There were five groups: 32 rats with hypertension were randomized into model, chitosan experimental and positive drug groups (n=8 per group); another 8 healthy rats served as controls. The rats in the model and control groups were given the injection of the same amount of normal saline via tail vein, the rats in the chitosan group received the injection of 1 mg/kg chitosan via the tail vein, those in the experiment group received the injection of 1 mg/kg PEG-modified chitosan nanoparticles loaded with ACE-shRNA, and the positive drug group rats were treated with 0.5 mg/kg benazepril hydrochloride via gastric lavage at 1 and 10 days, respectively.
    RESULTS AND CONCLUSION: The blood pressure in the experimental group at 3 days after treatment was significantly lower than that at 1 day (P < 0.05). Aorta, renal and cardiac biopsies showed positive for green fluoresce in the experimental group, which was consistent with the in vivo distribution of ACE. At 3 days after treatment, compared with the model group, in the experimental group, ACE mRNA expression and levels of myocardial hypertrophy-related indicators were significantly decreased, and myocardial hypertrophy was significantly improved (P < 0.05). These results revealed that PEG-modified ACE-shRNA chitosan nanoparticles can reduce the blood pressure and repair the injured heart of rat models of hypertension, which may be associated with ACE.

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    Histological changes of the bone-implant interface after calcium sulfate/ polyaminoacid artificial bone carrying triple-anti-tuberculosis drugs is implanted into the spinal tuberculosis focus
    Zhang Zhuo, Sun Yu-hang, Geng Guang-qi, Shi Jian-dang, Wang Zi-li, Niu Ning-kui, Ma Wen-xin, Liu Hai-tao, Wang Qian
    2016, 20 (47):  7027-7033.  doi: 10.3969/j.issn.2095-4344.2016.47.005
    Abstract ( 409 )   PDF (12398KB) ( 224 )   Save

    BACKGROUND: Most researchers have devoted to study the control-release system in spinal tuberculosis focus and implant material for bone defects, but the effective combination to obtain a novel implant material and its treatment outcomes are rarely reported.
    OBJECTIVE: To observe the histological change of the implant-bone interface after implantation of the calcium sulfate/polyaminoacid artificial bone carrying triple-anti-tuberculosis drugs including isoniazid, rifampicin and pyrazinamide in a rabbit model of spinal tuberculosis, and to assess the fusion ability of the material.
    METHODS: Thirty-six New Zealand rabbits were randomly divided into experiment, control and blank control groups (n=12 per group). Models of spinal tuberculosis were established in the rabbits and randomly assigned into either experiment or control groups, followed by implantation with the calcium sulfate/polyaminoacid artificial bone carrying triple-anti-tuberculosis drugs including isoniazid, rifampicin and pyrazinamide, or the calcium sulfate/polyaminoacid artificial bone, respectively. Healthy controls received the implantation with calcium sulfate/polyaminoacid artificial bone only.
    RESULTS AND CONCLUSION: Hematoxylin-eosin staining showed that the artificial bone was covered by fibers and tightly adhered to the wound in each group at 2 weeks after implantation, the graft started to degrade obviously at the 4th week, degraded mostly at the 8th week, and disappeared completely at the 16th week. There was obvious callus formation at 4 weeks after implantation in the experiment group, but the bone healing was later than that of the blank control group. The bone healing ended in the control group. In the blank control group, callus formation and early osteogenesis appeared at the 4th week, and healed completely at the 16th week. Transmission electron microscope and scanning electron microscope revealed that osteoblasts could crawl through the gap of materials to form new bone. These results suggest that the calcium sulfate/polyaminoacid artificial bone carrying triple-anti-tuberculosis drugs can be used as a scaffold, and osteocytes in the bone defect area can crawl through the gap of materials, thereby promoting bone osseointegration at the bone-implant interface.

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    Osteoinductive calcium phosphate ceramics repair alveolar cleft defects
    Chen Hao-dong, Yao Jin-feng, Liang Zhi-gang
    2016, 20 (47):  7034-7042.  doi: 10.3969/j.issn.2095-4344.2016.47.006
    Abstract ( 286 )   PDF (8069KB) ( 225 )   Save

    BACKGROUND: In our previous studies, we had prepared calcium phosphate ceramics with better ectopic osteogenesis.
    OBJECTIVE: To explore the effect of novel osteoinductive calcium phosphate ceramics in the repairing of alveolar cleft.
    METHODS: Bilaterl alveolar defects were created in nine immature beagles. Three months later, osteoinductive calcium phosphate ceramics with high modular surface (experimental group) and smooth surface (control group) were randomly implanted in each side of the defect. Meanwhile, the corresponding material was implanted into the thigh muscle. New bone formation in the implanted region, osteogenesis in the implanted region and muscle, and respair results were respectively observed by fluorescence microscope, light microscope and CT at 4, 8 and 12 weeks after implantation.
    RESULTS AND CONCLUSION: (1) Fluorescence microscope observation: A circular permutation of red, yellow and green fluorescent strip could be observed in both two groups. (2) Light microscope observation: At 12 weeks after implantation, in the experimental group, the bone reconstruction was obvious, the implant material was decomposed gradually, the gap was filled with a large number of mature bone that combined with the rest material closely, and numerous Haversian canals appeared; the control group was similar but slightly inferior to the experimental group in the quality of new bone. The experimental group material successfully induced heterotopic osteogenesis in muscle, while the control did not. (3) CT examination: The two group materials restored the appearance and continuity of the alveolar ridge, and made no effect on the eruption of permanent teeth in both sides of the defect. To conclude, our findings suggest that the novel osteoinductive calcium phosphate ceramic exhibits advantages in alveolar cleft repair with earlier osteogenesis activation, faster osteogenesis rate and more bone formation than those traditional materials.

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    Therapeutic effect of porous tantalum implantation for osteonecrosis of the femoral head and construction of a prognostic model
    Mao Zi-mu, Yin Kun, Wang Yu-ze, Li Peng-cui, Guo Li, Wei Xiao-chun
    2016, 20 (47):  7043-7050.  doi: 10.3969/j.issn.2095-4344.2016.47.007
    Abstract ( 290 )   PDF (1536KB) ( 275 )   Save

    BACKGROUND: Porous tantalum implantation is a novel treatment method for osteonecrosis of the femoral head (ONFH), but its therapeutic effect is under discussion.
    OBJECTIVE: To analyze the survival data of two kinds of porous tantalum implants for early- and mid-stage ONFH, and to determine the independent prognostic factors.
    METHODS: Thirty-four cases of ARCO stages I-III ONFH were enrolled, and 25 patients (31 hips) were treated with porous tantalum implantation (simple group), and the other 9 patients (10 hips) treated with porous tantalum implantation combined with bone allograft (combination group). Afterwards, the Harris scores and total survival rate of hips were recorded; the prognostic factors were analyzed by Cox regression.
    RESULTS AND CONCLUSION: The mean follow-up time in the simple and combination groups was (32.9 ±16.8) and (25.3±12.4) months respectively. The Harris scores at the last follow-up in the two groups were both higher than those before surgery, and moreover, the scores were higher in the simple group than the combination group (P < 0.05). The total survival rate of hips significantly differed between groups (P=0.014). Cox regression showed that the history of hormone, accompanied with other chronic diseases, and adverse reactions made effects on the prognosis. These results suggest that porous tantalum implantation is an effective treatment method for ARCO stages I-III ONFH, and it can improve the functional recovery and survival rate of the hips.

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    Glycolic acid loaded with chondrocytes repairs laryngeal cartilage defects
    Jia Min, Yuan Kun
    2016, 20 (47):  7051-7056.  doi: 10.3969/j.issn.2095-4344.2016.47.008
    Abstract ( 444 )   PDF (1034KB) ( 246 )   Save

    BACKGROUND: A three-dimensional biodegradable scaffold is important for tissue-engineered cartilage construction, and it that can provide conditions for cell attachment and proliferation.
    OBJECTIVE: To observe the treatment outcomes of glycolic acid loaded with chondrocytes in laryngeal cartilage repair.
    METHODS: Sixty New Zealand white rabbits were enrolled and randomly divided into control and experimental groups. Laryngeal cartilage defect models were established in each group, followed by implanted with glycolic acid loaded with chondrocytes and glycolic acid, respectively. Gross and histological observations were conducted at 4 and 8 weeks after implantation.
    RESULTS AND CONCLUSION: Gross observation showed that at 4 weeks after implantation, a deep red wound with an obvious boundary was seen in the control group; the dark red and smooth defect parallel to the surrounding tissue was found in the experimental group. Toluidine blue staining revealed that at 8 weeks after implantation, the laryngeal defect site showed no obvious inflammation and cartilage collapse, with numerous newly-formed chondrocytes in the experimental group; in contrast, mild inflammation and cartilage collapse were found in the defect region of the control group, and few newly-formed chondrocytes appeared. The positive areas of glycosaminoglycan and type II collagen in the experimental group were significantly larger than those in the control group at 4 and 8 weeks after implantation (P < 0.05). These results indicate that glycolic acid loaded with chondrocytes contributes to the repair of laryngeal cartilage defects.

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    Bone morphogenetic protein sustained-release microspheres combined with   platelet-rich gel contribute to the proliferation and differentiation of bone marrow stromal stem cells
    Lu Xiao-lang, Zheng Yi-jing, Cheng Tao, Ye Chao, Hong Jian-jun
    2016, 20 (47):  7057-7063.  doi: 10.3969/j.issn.2095-4344.2016.47.009
    Abstract ( 298 )   PDF (4567KB) ( 207 )   Save

    BACKGROUND: Various growth factors together participate in the different stages of bone healing, but the current tissue-engineered materials limited on single type and concentration cannot obtain satisfactory outcomes. There is still a lack of study on the novel tissue-engineered material releasing two or more growth factors in order.
    OBJECTIVE: To observe the effect of platelet-rich gel (PRG) combined with poly(lactide-glycolide acid) (PLGA) microspheres encapsulating bone morphogenetic protein-2 (BMP-2) on the proliferation and osteoblastic differentiation of bone marrow stromal stem cells.
    METHODS: PLGA microspheres loading BMP-2 were prepared by multiple emulsion method, and the encapsulation rate, morphology and volume of microspheres as well as in vitro releasing rate of BMP-2 were measured. The eligible microspheres combined with the activated PRG were co-cultured with human bone marrow stromal stem cells on the PLGA three-dimensional scaffold. Additionally, bone marrow stromal stem cells were divided into six groups including platelet poor gel, PRG, BMP-2/platelet poor gel, BMP-2/PRG, BMP-2 microspheres/platelet poor gel and BMP-2 microspheres/PRG groups, and the preprocessed PLGA scaffold was added into each group. The DNA content, alkaline phosphatase activity and mRNA expression levels of osteopontin and osteocalcin were observed.
    RESULTS AND CONCLUSION: The DNA content of bone marrow stromal stem cells was higher in all PRG scaffolds compared with the platelet poor gel scaffolds. The alkaline phosphatase activity and mRNA expression levels of osteopontin and osteocalcin in the BMP-2 microspheres/platelet poor gel and BMP-2 microspheres/PRG groups were markedly higher than those in the other four groups. These results suggest that the BMP-2 sustained-release microspheres combined with PRG are able to enhance the proliferation and differentiation of bone marrow stromal stem cells.

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    Effect of polytetrafluoroethylene artificial blood vessels on platelet aggregation and its cytocompatibility
    Jiang Zheng-ming, Chen Kui, Hu Cai-na
    2016, 20 (47):  7064-7069.  doi: 10.3969/j.issn.2095-4344.2016.47.010
    Abstract ( 389 )   PDF (4064KB) ( 251 )   Save

    BACKGROUND: Polytetrafluoroethylene artificial blood vessels have been extensively used in clinic. However, there is still a lack of basic study on it.
    OBJECTIVE: To observe the effect of polytetrafluoroethylene artificial blood vessels on platelet aggregation and its cytocompatibility.
    METHODS: Effect on platelet aggregation: Dynamic platelet clotting time and plasma recalcification time were detected. Normal saline, distilled water and polytetrafluoroethylene artificial blood vessels were added into the rabbit red cell suspensions, respectively, to count the hemolysis ratio. Cytocompatibility: Primary myocardial cells from Sprague-Dawley rats were respectively seeded onto the common round coverslip and polytetrafluoroethylene artificial blood vessels, and the lactate deshydrogenase release and cell proliferation were detected at 3 and 5 days, respectively.
    RESULTS AND CONCLUSION: Polytetrafluoroethylene artificial blood vessels made no effects on the platelet clotting time and plasma recalcification time and 2.3% hemolysis ratio was observed. Compared with the common round coverslip, the myocardial cell proliferation and lactate deshydrogenase release showed no significant changes on the polytetrafluoroethylene artificial blood vessels. These results suggest that the polytetrafluoroethylene artificial blood vessel makes no effect on platelet aggregation and holds good hemocompatibility and cytocompatibility.

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    Hemostatic effect of soluble hemostatic gauze on liver trauma in rabbits
    Liu Xiao-jun, Xu Yu-yin, Zhou Jing, Zhang Juan-li, Zhou Xiao-ting, Tian Yuan
    2016, 20 (47):  7070-7075.  doi: 10.3969/j.issn.2095-4344.2016.47.011
    Abstract ( 535 )   PDF (4332KB) ( 628 )   Save

    BACKGROUND: Modified cellulose dressing as an important part of polysaccharide hemostatic material has its unique advantages compared with gelatin sponge and fibrin glue.
    OBJECTIVE: To compare the hemostatic effect and histocompatibility of medical gauze, absorbable hemostatic gauze and soluble hemostatic gauze. 
    METHODS: After establishment of liver trauma models, 36 New Zealand rabbits were randomly divided into three groups (n=12) depending on different hemostatic materials. Injury wounds were covered with soluble hemostatic gauze (mainly made of sodium carboxymethyl cellulose, experimental group), absorbable hemostatic gauze (mainly made of sodium carboxymethyl cellulose, control group) and medical gauze (normal group), respectively. The gauze was only taken out in the normal group. A hemostasis trial on liver injury was carried out to investigate the bleeding time and bleeding amount. After 1, 3, 7 and 10 days, wound healing was observed histologically in each group. 
    RESULTS AND CONCLUSION: The bleeding time and bleeding amount in the experimental and control groups were lower than those in the normal group (both P < 0.05), but no statistical difference was found between the experimental and control groups. After 1 day of implantation, the soluble hemostatic gauze was absorbed completely, and the absorbable hemostatic gauze was absorbed with no residual until the 10th day. Experimental and control groups shared similar pathological changes. In these two groups, mild fibrosis and fibrous scar appeared, a better improvement in wound inflammation was shown at 10 days compared with that at 7 days, and the wound gradually healed. In the normal group, there were no obvious lesions except mild tissue edema around the wound. All these findings suggest that the soluble hemostatic gauze has better hemostatic effect and histocompatibility.

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    Kyphoplasty with bone cement repairs osteoporotic thoracolumbar vertebral fractures associated with peripheral wall damage: a 2-year follow-up
    Sun Zhi-yong, Qian Zhong-lai, Zhu Xiao-yu, Chen Kang-wu, Pi Bin, Yang Hui-lin
    2016, 20 (47):  7076-7082.  doi: 10.3969/j.issn.2095-4344.2016.47.012
    Abstract ( 323 )   PDF (1571KB) ( 284 )   Save

    BACKGROUND: Kyphoplasty with bone cement has achieved good therapeutic efficacy on osteoporotic thoracolumbar fractures; however, there is little report about its application in the repair of vertebral fractures associated with vertebral body wall damage, due to the risks of bone cement leakage and puncture.
    OBJECTIVE: To evaluate the treatment outcomes of kyphoplasty with bone cement on osteoporotic thoracolumbar fractures associated with peripheral wall damage and to assess its short-term clinical effect.
    METHODS: Sixty-five patients (42 females and 23 males, mean age=71.5 years) with osteoporotic thoracolumbar fractures associated with peripheral wall damage were enrolled and treated with kyphoplasty. The anterior and mid-vertebral body height, complications, visual analog scale scores and Oswestry disability index were observed before, immediately and 1, 6 and 24 months postoperatively.
    RESULTS AND CONCLUSION: The visual analog scale scores, Oswestry disability index and Cobb angle were decreased significantly, and the anterior and mid-vertebral body height were increased significantly from pre- to post-operation (P < 0.05). All above improvements appeared to have no significant changes from post-operation to 2-year follow-up (P > 0.05). Cement leakage was detected in 7 cases (10 vertebrae), but did not cause severe clinical symptoms. There were no injuries to spinal nerve root and no complications of infection, bleeding, pulmonary embolism, stroke, or cardiac cerebral arrest. These findings indicate that kyphoplasty with bone cement is safe and feasible to treat osteoporotic thoracolumbar fractures associated with peripheral wall damage, leading to restoration of the vertebral height, reduction in pain, correction of the kyphotic deformity and satisfaction with the short-term curative effect.

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    Effects of pretreatment in post space on the bonding strength of self-adhesive resin cement to fiber posts
    Feng Xin-yan, Gao Cheng-zhi
    2016, 20 (47):  7083-7089.  doi: 10.3969/j.issn.2095-4344.2016.47.013
    Abstract ( 297 )   PDF (1106KB) ( 236 )   Save

    BACKGROUND: The bonding interface of resin cements with dentin is unstables, therefore, improvement on the bonding strength is of great significance.
    OBJECTIVE: To evaluate the effects of different pretreatments to post space on bonding strength of the self-adhesive resin cement EmbraceCoreTM Resin Cement to fiber posts after phosphoric acid etching or self-etching.
    METHODS: Twenty-five human mandible canines or premolars with single-rooted canal were selected. After conventional root canal treatment and post space preparation, they were randomly divided into five groups (n=5 per group): group I (control group): 0.9% normal saline irrigation; group II: etching with 35% phosphoric acid for 15 seconds; group III: self-etching with CLEARFILTM SE BOND binder for 20 seconds; group IV: etching with 35% phosphoric acid for 15 seconds and bonding with single bong 2; group V: self-etching with CLEARFILTM SE BOND binder for 20 seconds and bonding with CLEARFILTM SE BOND binder. Fiber posts were edusing self-adhesive resin cement EmbraceCoreTM Resin Cement. The thin-slice push-out test was performed to record the bonding strengths, and the failure modes of fiber posts were observed by stereomicroscope.
    RESULTS AND CONCLUSION: The bond strength of groups I-V were as follows: (8.66±2.43), (7.05±3.0), (7.37±2.83), (9.88±2.9), and (10.04±2.86) MPa. Groups II, IV and V showed significantly different bond strength from the group I (P < 0.05), but there were no significant differences between groups III and I (P > 0.05). The main failure models in the groups I, II and III were A1 and A2, and less B1 and B2 appeared. The failure modes in the groups IV and V also focused on the A1 and A2, but B1 and B2 increased gradually. These results indicate that neither the pretreatments by phosphoric acid etching nor by self-etching in root canal dentin can improve the bonding strength of EmbraceCoreTM Resin Cement to fiber posts, but the use of binder relative to phosphoric acid etching or self-ctching is helpful. 

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    Synthesis of MnFe2O4 nanomicelles and its application in magnetic resonance molecular imaging
    Yang Hua, Gong Ming-fu, Zou Li-guang, Zhang Song, Shu Tong-sheng, Zhou Pei-hua
    2016, 20 (47):  7090-7096.  doi: 10.3969/j.issn.2095-4344.2016.47.014
    Abstract ( 371 )   PDF (2352KB) ( 249 )   Save

    BACKGROUND: Studies have shown that the saturation magnetization of nanoparticles can be increased by increasing of particle size of nanoparticles or cluster-like aggregation of multiple nanoparticles. But the increased particle size can reduce the cycle time of nanoparticles in the body.
    OBJECTIVE: To synthesize MnFe2O4  nanomicelles and explore the feasibility of its application in magnetic resonance molecular imaging.
    METHODS: MnFe2O4  nanoparticles were synthesized using thermal decomposition method and self-assembled with polyethylene glycol-polycaprolactone amphiphilic diblock copolymers (PEG-PCL) to construct PEG-PCL-MnFe2O4  nanomicelles. The characteristics of the MnFe2O4 nanoparticles and nanomicelles were tested. Then, MnFe2O4  nanoparticles and nanomicelles at different iron concentrations (0, 0.01, 0.02, 0.03, 0.04, 0.06, 0.08, 0.1, 0.2, 0.4, 0.6, 0.8 mmol/L) were placed into EP tubes. Relaxation rate of the nanomicelles were measured using magnetic resonance scanner.
    RESULTS AND CONCLUSION: (1) MnFe2O4  nanoparticles appeared as round under transmission electron microscopy. The size of nanoparticles was 11 nm with good monodispersion. The Zeta-particle size was (11.18±1.72) nm. The molar ratio of Fe/Mn was 2.13:1. The size of PEG-PCL-MnFe2O4  nanomicelles ranged from 52 to 86 nm, with a mean Zeta-particle size of (78.8±12.4) nm. (2) The signal intensity (SI) change of PEG-PCL-MnFe2O4  nanomicelles and PEG-PCL-Fe3O4 nanomicelles shared similar trend according to iron concentration. With the increasing of iron concentration, SI first increased and then decreased in T1WI, and it gradually decreased in T2WI and T2*WI. The SI changes in T2*WI were significantly stronger than that in T2WI and T1WI. Taken together, our results show that PEG-PCL-MnFe2O4 nanomicelles are expected to perform as a sensitive contrast agent used in T2WI as their moderate particle size, good monodisperse and strong T2 relaxation.

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    A novel domestic-made stent-graft in endovascular abdominal aortic aneurysm repair: outcome of short- and medium-term follow-up and experience summary of a single-center controlled clinical trial
    Liu Ming-yuan, Liu Bing, Wang Hao-fu
    2016, 20 (47):  7097-7105.  doi: 10.3969/j.issn.2095-4344.2016.47.015
    Abstract ( 465 )   PDF (1877KB) ( 237 )   Save

    BACKGROUND: Limited by the high financial burden of stent-graft and proof of evident-based medicine, the popularization of endovascular abdominal aortic aneurysm repair, a mini-invasive method, is impeded in China. In order to reduce costs, development of domestic-made stents is imperative, but the relative research is still rare.
    OBJECTIVE: To compare the effect of domestic-made stent-graft (Percutek) and Gore Excluder in the endovascular abdominal aortic aneurysm repair.
    METHODS: From January to November 2014, there were 32 male patients with infrarenal abdominal aortic aneurysm, aged 56-79 years old with mean age of (70.2±6.9) years, admitted in the Vascular Surgery Department of the Affiliated Hospital of Qingdao University. Clinical data were collected and retrospectively analyzed. There were 11 cases undergoing domestic-made stent-graft repair and 21 undergoing Gore Excluder repair. Aortic CT angiography was performed at 1 and 6 months after surgery, and every 6 months thereafter to evaluate the effect of the two modalities.
    RESULTS AND CONCLUSION: Domestic-made stent-grafts were successfully implanted into the 11 patients, and there were 1 case of late type I endoleak, 1 of type II endoleak, 1 of iliac occlusion and 1 of death after surgery. Totally 11 stent-graft trunks, 18 iliac stent-grafts, 1 Cuff, and 1 bare metal stent were implanted in the domestic-made stent-graft group (2.8 stents/case). Totally 21 patients were subjected to Gore Excluder repair with the success rate of 90%, and 2 cases of intraoperative I type endoleak (10%), 2 of postoperative I type endoleak and 2 of postoperative II type endoleak were observed. Totally 21 stent-graft trunks, 28 iliac stent-grafts and 3 Cuff were implanted in the Gore Excluder group (2.47 stents/case). These results suggest that the novel domestic-made stent-graft has achieved a satisfactory outcome in endovascular abdominal aortic aneurysm repair, showing no significant differences in related indicators with the Gore Excluder; however, the long-term outcomes still need to be further studied.

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    Biocompatibility of different hemodialysis membrane materials in the treatment of severe acute pancreatitis
    Jiang Qi-dong, Wu Chang-xue
    2016, 20 (47):  7106-7111.  doi: 10.3969/j.issn.2095-4344.2016.47.016
    Abstract ( 335 )   PDF (1012KB) ( 182 )   Save

    BACKGROUND: In the clinical treatment of severe acute pancreatitis, there are different dialysis membrane materials. But the differences among these dialysis membrane materials are unclear.
    OBJECTIVE: To compare the biocompatibility of polysulfone and cellulose acetate dialysis membranes.
    METHODS: Totally 100 severe acute pancreatitis patients were included, including 51 males and 49 females, aged 34 to 81 years, and all were subjected to hemodialysis treatment (5 hours once, three times per week). Polysulfone membrane was used in 50 cases, and cellulose acetate dialysis membrane used in the other 50 cases. After 3 months of follow-up, the time of recovery from abdominal pain and abdominal distension, the time of blood amylase returning to normal levels, therapeutic efficacy and level of inflammatory factors were compared between two groups.
    RESULTS AND CONCLUSION: There were no differences in the time of recovery from abdominal pain and abdominal distension, the time of blood amylase returning to normal levels, and therapeutic efficacy between the two groups. The levels of interleukin-6, C-reactive protein and tumor necrosis factor alpha in the two groups were significantly lower than those before hemodialysis treatment (P < 0.05), but there was no significant difference between the two groups. Results show that both polysulfone and cellulose acetate membranes used in hemodialysis treatment of severe acute pancreatitis have good biocompatibility.

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    A chemosynthetic medical adhesive containing alpha-N butyl cyanoacrylate for liver hemostasis
    Zhang Fei, Zhao Jun, Meng Xing-kai, Li Jian-feng
    2016, 20 (47):  7112-7118.  doi: 10.3969/j.issn.2095-4344.2016.47.017
    Abstract ( 578 )   PDF (1319KB) ( 279 )   Save

    BACKGROUND: There are chemosynthetic and biological medical adhesives, and the former mainly composed by cyanoacrylate, holds poor hydrophilicity and is easy to break off, thereby achieving unsatisfactory hemostatic effect.
    OBJECTIVE: To evaluate the hemostatic and adhesion effect of the modified α-N butyl cyanoacrylate (NBCA) by the hemostatic test in white rabbit livers.
    METHODS: Material imprvement: cyanoacrylate monomer was prepared and its components and contents were analyzed by infrared spectrum and gas chromatograph. Sodium lauroyl sarcosinate was used as surfactant to improve the cohesive force between NBCA and tissues and increase the hydrophility. Hemostatic test in the liver incision: the liver incision of rabbits in three groups were sewn with absorbable suture and then covered with gelatin sponge (control group), cyanoacrylate and NBCA medical adhesives, respectively. Blood loss and bleeding time were recorded within 20 minutes. Hemostatic test in the liver section: the liver sections in two groups were smeared with surfactant plus NBCA and cyanoacrylate, respectively. The gross appearance of wound and its adherence to the omentum majus, as well as the histological changes by hematoxylin-eosin staining were observed at 1, 10 and 20 days postoperatively.
    RSULTS AND CONCLUSIPON: The adhesiveness of NBCA medical adhesive was excellent. Infrared spectrum and gas chromatograph found that the main component was NBCA up to 84.56%, with 8.2% reactants and 3.3% byproducts. The modified NBCA medical adhesive significantly decreased the blood loss and bleeding time compared with the control group (P < 0.01), and did not significantly differ from the cyanoacrylate (P > 0.05). In addition, the modified NBCA adhered more firmly to the wound, and was absorbed completely at 20 days postoperatively, showing no adverse reaction. These results suggest that NBCA is better and more stable than gelatin sponge, and exerts overt hemostatic effect causing no adverse reaction.

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    Influence of Gluma desensitizing agents on dentin bond strength: a Meta-analysis
    Li Wang-yang, Zhang Ling, Zhang Hui, Li Ai-ling, Guo Ling
    2016, 20 (47):  7119-7126.  doi: 10.3969/j.issn.2095-4344.2016.47.018
    Abstract ( 415 )   PDF (1640KB) ( 232 )   Save

    BACKGROUND: Desensitization agent is widely used to relieve tooth sensitivity after tooth preparation. However, some components in the desensitization agent for certain affect the dentin bond strength between prosthesis and dentin. Given this, choosing a proper desensitization agent is under discussion.
    OBJECTIVE: To investigate the influence of Gluma desensitizing agents on bond strength to dentin by Meta-analysis.
    METHODS: A computer-based retrieval of PubMed, EMbase, EBSCO EDLINE, The chrane Library, ScienceDirect, Web Of Science, OVID, CBMbase, CJFD, CqVip and WanFang databases combined with manual searching was performed for randomized controlled trials or controlled clinical trials about effect of desensitizing agents on dentin bond strength. The retrieval time ranged from the creation date to June 18, 2016, without region and language limits. In accordance with inclusion/exclusion criteria, related data were extracted, and the qualitative and quantitative analysis of the included studies was performed by two researchers independently, and then the Meta-analysis was conducted using RevMan 5.2 software.
    RESULTS AND CONCLUSION: There was no significant difference in the shear bond strength of self-etching or total-etching adhesive to dentin between two groups, and the same results were found when comparing the shear bond strength of self-etching and total-etching adhesive to dentin. The Gluma had a beneficial effect on the shear bond strength of self-adhesive. These results indicate that when Gluma used as the desensitizing agent, self-adhesive materials are the first choice, and secondly the self-etching or total-etching adhesive materials containing acid or able to dissolve protein crystals are preferred.

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    Application of felodipine sustained-release tablets in the hypertension treatment in China
    Wu Jin
    2016, 20 (47):  7127-7132.  doi: 10.3969/j.issn.2095-4344.2016.47.019
    Abstract ( 648 )   PDF (1095KB) ( 239 )   Save

    BACKGROUND: Felodipine sustained-release tablets are taken orally once daily, which not only exhibit a flat plasma-concentration curve, but also have characteristics of stable effect-acting, good absorption in vivo, high bioavailability and good compliance.
    OBJECTIVE: To introduce the application status of felodipine sustained-release tablets in the hypertensive treatment of China.
    METHODS: A computer-based research of CNKI database was performed for literatures published from January 1, 2005 to July 1, 2016. Using the keywords of “felodipine sustained-release tablets, hepertension”, 174 articles were retrieved; and when retrieving “felodipine sustained-release tablets, materials”, 22 were obtained. Thirty literatures were enrolled finally for analysis according to the exclusion criteria.
    RESULTS AND CONCLUSION: Felodipine sustained-release tablets have been popularized to the hypertensive treatment in our country, and obtain satisfactory treatment outcomes for mild and moderate spontaneous hepertension, which are similar with those of the nifedipine sustained-release tablets, metoprolol sustained-release tablets and benazepril hydrochloride tablets. Felodipine sustained-release tablets also induce slight adverse reactions, such as headache, flush, palpation and swelling of ankles. For patients with hypertension cannot be alleviated through single use of felodipine sustained-release tablets, combination with other types of antihypertensive drugs including beta blockers, angiotensin converting enzyme inhibitors and diuretics is advisable. Compound felodipine sustained-release tablets have been used in clinic, and numerous multicenter, double-blind, randomized control trials have proved its effectiveness and safety. Therefore, compound felodipine sustained-release tablets are another choice when single treatment shows no improvement on patients with spontaneous hypertension.  

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    Current situation of customised denture manufacturing enterprises in Sichuan, China
    Zhou Jing, Ye Xiang, Zhu Xiang-dong, Jiang Xue-hua
    2016, 20 (47):  7133-7138.  doi: 10.3969/j.issn.2095-4344.2016.47.020
    Abstract ( 293 )   PDF (1091KB) ( 194 )   Save

    BACKGROUND: As the industry of customised denture develops rapidly, a series of problems such as non-standard usage of the raw materials, poor quality of employees, uneven quality have emerged. But comprehensive research of the whole industry is not reported yet.
    OBJECTIVE: To comprehensively analyze the running state of customised denture manufacturing enterprises in Sichuan and point out pertinent suggestions.
    METHODS: The related data of customised denture in Sichuan was collected through questionnaires, telephone communication, on-site inspection and expert discussion seminar and other forms. These data was statistically analyzed.
    RESULTS AND CONCLUSION: Customised denture manufacturing enterprises in Sichuan are still characterized by a small-scale, less advanced equipments and lower professional and technical ability of employees, but their sales are in steady and rapid growth, and the industry is in high-speed development. Thereafter, the instructional suggestions are put forward for the further development of the industry of customised denture from the perspective of regulation. 

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    Safety and efficacy of implantation of two multifocal intraocular lenses in the treatment of senile cataract: study protocol for a randomized controlled clinical trial
    Yu Ping, Wang Qing, Liu Ling-ling
    2016, 20 (47):  7139-7144.  doi: 10.3969/j.issn.2095-4344.2016.47.021
    Abstract ( 393 )   PDF (994KB) ( 239 )   Save

    BACKGROUND: Phacoemulsification with intraocular lens (IOL) implantation has become a well-established treatment for senile cataract. The ideal IOL is characterized by good biocompatibility and resolution, with no spherical aberration. The Acri.LISA 366D is a refractive/diffractive multifocal IOL that differs from traditional multifocal IOLs. Its unique optical design can improve the patient's vision and reduce incident ray scattering, glare and halo.
    OBJECTIVE: To perform a comparative analysis between the Acri.LISA 366D and the Tecnis Z9001 diffractive multifocal IOL, to determine if there are any differences in biocompatibility and improvement in visual function.
    METHODS: A prospective, single-center, randomized, double-blind, parallel-controlled study will be conducted at the Affiliated Hospital of Qinghai University in China. Forty cataract patients aged 50–80 years will be randomly assigned to either the Acri.LISA 366D or Tecnis Z9001 IOL (n=20 per group). This study protocol has been approved by the Medical Ethics Committee of Qinghai University Affiliated Hospital in China (approval No. QHY1107K) and will be performed in accordance with the guidelines of the Declaration of Helsinki, formulated by the World Medical Association. Signed informed consent regarding trial procedure and treatment will be obtained from each patient or their guardians. This trial was registered at ClinicalTrials.gov (NCT02696496).
    RESULTS AND CONCLUSION: The primary outcome of the trial is to investigate the biocompatibility of the IOL after implantation. The secondary outcomes include visual acuity, refractive changes and the presence of any complications. Outcome measures will be evaluated at 1, 3, 6, 12 and 24 months after IOL implantation. It is anticipated that the data collected from this trial will provide evidence for IOL selection in senile cataract patients.

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