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16 July 2010, Volume 14 Issue 29 Previous Issue    Next Issue

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Pathologic changes of canine ureter caused by degradable and undegradable stent Wang Wei, Li Mu, Liu Shao-qian, Xu Huan, Li Hong 2010, 14 (29):  5321-5324.  doi: 10.3969/j.issn.1673-8225.2010.29.001 Abstract ( 128 )   PDF (569KB) ( 407 )   Save BACKGROUND: The presently used ureteral stent are made of undegradable silicone and polyurethane, which must be removed by operation after a certain period of implantation. OBJECTIVE: To observe the pathologic changes of canine ureter caused by poly-DL-lactic acid stent and polyurethane stent. METHODS: Poly-DL-lactic acid and polyurethane stents were implanted in different sides of canine ureters by operation. Ureteral incision specimens were obtained every two weeks. The pathologic changes of canine ureter were observed under light microscope. RESULTS AND CONCLUSION: Traumatic inflammation was the main pathological change of all ureteral specimens. Epithelial decortication, edema of the proper layer and disarrangement of the muscle layer were obvious at the second and the fourth weeks. The arteriolar congestion in proper layer was found at the sixth week. There was no significant disorder at the end of eighth week. The result demonstrated that Poly-DL-lactic acid stent has fairly good tissue compatibility. Related Articles | Metrics

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Preparation and property of closed dressing intelligent scaffolds Tang Na, Cai Wen-zhi, Deng Ling, Li Shu-juan, Wang Xiao-juan, Li Chao 2010, 14 (29):  5325-5328.  doi: 10.3969/j.issn.1673-8225.2010.29.002 Abstract ( 99 )   PDF (511KB) ( 438 )   Save BACKGROUND: In recent years, the wound dressing research has developed quickly, but few reports the closed dressings prepared by traditional Chinese medicine combined with polymer composite, the efficacy of existing wound dressings is limited and not suitable for all wounds. OBJECTIVE: To prepare closed dressing scaffolds loading traditional Chinese medicine, and to determine their properties. METHODS: Firstly the chitosan, gelatin and polyvinyl alcohol were mixed, while the above materials were additionally mixed with sodium alginate. The scaffolds were prepared by mixing, precooling and freeze drying. The properties of the enclosed dressing scaffolds was evaluated by water absorption, moisture content, relative moisture retention, permeability, porosity, and scaffold appearance. RESULTS AND CONCLUSION: Water absorption, moisture content, relative moisture retention and porosity of the mixture of chitosan, gelatin and polyvinyl alcohol were significantly better than those of the mixture containing chitosan, gelatin, polyvinyl alcohol and sodium alginate (P < 0.05). Chitosan, gelatin and polyvinyl alcohol are suitable to be used as closed dressing intelligent scaffolds. Related Articles | Metrics

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Effect of microencapsulated culture on the proliferation and functional expression of hepatocytes Huang Xiao-bo, Zhang Ying, Wang Wei, Sun Guang-wei, Zhu Jing, Xie Hong-guo, Ma Xiao-jun 2010, 14 (29):  5329-5333.  doi: 10.3969/j.issn.1673-8225.2010.29.003 Abstract ( 110 )   PDF (522KB) ( 349 )   Save BACKGROUND: The previous experiments have proved that, the configuration of hepatocarcinoma cells (HepG2) was changed during microencapsulated culture and the cellular skeleton was also rearranged. OBJECTIVE: Based on the previous study, this study was aimed to further investigate the effect of microencapsulated culture on the proliferation and function expression of HepG2 cells. METHODS: Human HepG2 cell lines were encapsulated in alginate-poly-L-lysine-alginate microcapsules. The configuration and microstructure of cellular spheroids, cellular proliferation and function expression were detected through microscopy and hematoxylin-eosin staining, MTT assay, Realtime RT-PCR and Elisa assay, respectively. RESULTS AND CONCLUSION: Microencapsulated HepG2 cells aggregated into clumps with tight junctions and proliferated in three-dimensional manner. Compared with the monolayer culture, the rate of cellular proliferation in microcapsules was reduced. However, the gene expression related with liver function and albumin secretion were increased in the microencapsulated HepG2 cells. The microenvironment provided by alginate-poly-L-lysine-alginate microcapsules can contribute to in vitro construction of HepG2 cells. The alginate-poly-L-lysine-alginate microcapsules can achieve in vitro culture of hepatocytes, it is a potential pattern of three-dimensional culture, and can be used in cancer therapy, high-flux drug screening and liver tissue engineering study. Related Articles | Metrics

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Injectable compound scaffold of fibrin gel/demineralized bone matrix to delay early osteoarthritis in rabbits He Jie, Zhao Jian-ning, Guo Ting 2010, 14 (29):  5334-5338.  doi: 10.3969/j.issn.1673-8225.2010.29.004 Abstract ( 65 )   PDF (602KB) ( 370 )   Save BACKGROUND: Both fibrin gel and demineralized bone matrix can be used as cartilage tissue engineered scaffolds to culture cartilage seed cells, due to their good biocompatibility and biodegradablity. These materials can act as carriers for growth factors to slow release growth factors and to continuously promote chondrocyte growth. OBJECTIVE: To verify the feasibility and efficacy of using injectable compound material made of fibrin glue and demineralized bone matrix as a scaffold to delay the progress of early osteoarthritis. METHODS: A homobody controlled animal experiment was designed. Sixteen rabbits were cut off the anterior cruciate ligament from posterior limbs to prepare knee osteoarthritis model, one side of the knee joint in rabbits was injected with composite scaffold and chondrocyte suspension for the experimental group. The other side of the knee joint was injected with equal volume of saline as the control group. The articular cartilage was harvested 12 weeks later, for respectively hematoxylin-eosin staining, Masson staining, II collagen immunohistochemical staining. In accordance with Wakitani standards and Outerbridge classification, the standard score was redefined, the cartilage degenerations in the two groups were evaluated. RESULTS AND CONCLUSION: In the experimental group, articular cartilage surface was smooth, cartilage lacuna could be seen, the structural cartilage degeneration was lighter than that in control group; chondrocyte and collagen type II were slightly less than normal cartilage, joint capsule tissue exhibited no expression of collagen type II. Comprehensive score of the experimental group was lower than the control group (P < 0.01). Injectable fibrin glue/demineralized bone matrix composite scaffold can provide a good composite scaffold for early osteoarthritis and bone defects. Related Articles | Metrics

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Transfecting human transformation growth factor beta 3 gene into precartilaginous stem cells cultured in three-dimensional self-assembled peptide nanofiber scaffold of KLD-12 Ding Ran, Zhang Yong, You Hong-bo, Li Feng, Sun Kai 2010, 14 (29):  5339-5343.  doi: 10.3969/j.issn.1673-8225.2010.29.005 Abstract ( 113 )   PDF (511KB) ( 442 )   Save BACKGROUND: Previous tests of our research group have proved that, exogenous cytokines human transforming growth factor-β3 (hTGF-β3) has a strong capacity of inducing precartilaginous stem cells (PSCs) differentiate to mature cartilage and of promoting the proliferation. Abroad studies also confirmed a beneficial effect on the proliferation and differentiation of cartilage-derived stem cells in three-dimensional culture of the self-assembled peptide nanofiber scaffold. OBJECTIVE: To transfect the hTGF-β3 gene in the PSCs cultured in three-dimensional self-assembled peptide nanofiber scaffold of KLD-12, and to compare the transfection efficiency with PSCs cultured in two-dimensional medium. METHODS: The PSCs were obtained and purified using magnetic-activated cell sorting method, then transplanted into the self-assembled peptide nanofiber scaffold of KLD-12. The gene of hTGF-β3 was respectively transfected into the PSCs cultured in self-assembled scaffold and common two-dimension medium by means of xfectTM stem nano-transfection reagent. After 48 hours, the gene expression levels of hTGF-β3 were detected by immunofluorescence and RT-PCR, and the concentration of TGF-β3 in the supernatant of medium was determined in different groups and different time points after transfection by the method of ELISA. RESULTS AND CONCLUSION: Immunofluorescence results showed that the rate of TGF-β3-positive cells in the group of PSCs cultured in three-dimensional self-assembled scaffold of KLD-12 was higher than those cultured in common two-dimensional medium (P < 0.05), which was consistent with the test results of RT-PCR. By the method of ELISA, the concentration of TGF-β3 in the supernatant of medium increased at 24 hours after transected, and reached peak after 72 hours, then decreased a little and entered the plateau stage. It’s indicated that the transfection efficiency of hTGF-β3 gene in PSCs cultured in self-assembled peptide nanofiber scaffold is higher than the group in common two-dimensional medium. Related Articles | Metrics

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Biocompatibility of hydroxyapatite surface modified titanium skirt for keratoprosthesis: Scanning electron microscopy observation Li Zhao-hui, Huang Yi-fei, Ma Xiao, Huang Jing-xiang, Cui Fu-zhai 2010, 14 (29):  5346-5350.  doi: 10.3969/j.issn.1673-8225.2010.29.007 Abstract ( 134 )   PDF (669KB) ( 397 )   Save BACKGROUND: Keratoprosthesis surgery may be alternative in patients with corneal blindness of both eyes. Currently, researches for improving biocompatibility between the keratoprosthesis and the host tissue to achieve biological healing are predominant. OBJECTIVE: To evaluate the biocompatibility of hydroxyapatite surface modified titanium skirt for keratoprosthesis by scanning electron microscopy. METHODS: The bioactive hydroxyapatite coating was prepared on pure titanium for keratoprosthesis by an acid-alkali chemical pretreatment. The fibroblasts of rabbit cornea at 4 to 6 passages were directly seeded on hydroxyapatite modified titanium surfaces, pure titanium surfaces and glass surfaces. Cell adhesion, proliferation and morphology were detected at 3, 24, 48, 72 hours by scanning electron microscopy. A total of 18 normal New Zealand white rabbits were randomly divided into two groups. Skirt of hydroxyapatite modified titanium and pure titanium were implanted into the right eye corneal stroma of rabbits for 6 and 12 weeks, respectively. The growth and adhesion of the corneal tissue on the surface of skirt were examined by scanning electron microscopy. RESULTS AND CONCLUSION: The in vitro experiment showed that, cells on hydroxyapatite modified titanium surfaces had greater spreading area and longer stress fibers than that on the pure titanium at 3 and 24 hours. Both hydroxyapatite modified titanium and pure titanium were superior to glass surface. The number of viable cells was the highest on hydroxyapatite modified titanium surfaces (P < 0.05). At 72 hours, hydroxyapatite modified titanium surfaces were totally covered by collagen. The in vivo experiment showed that, the extracellular matrix deposited well on the surface of hydroxyapatite modified titanium, tightly adhered with hydroxyapatite. The pure titanium was only covered with corneal tissues. Hydroxyapatite surface modification could improve the biocompatibility of pure titanium skirt for keratoprosthesis. Related Articles | Metrics

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Ultrasound-assisted micro-arc oxidation to prepare biocoatings containing lanthanum on the surface of titanium alloy: Biocompatibility evaluation Liu Ji-guang, Bao Dian-rui, Bi Qing-wei, Wu Zhi-feng, Li Mu-qin 2010, 14 (29):  5351-5354.  doi: 10.3969/j.issn.1673-8225.2010.29.008 Abstract ( 148 )   PDF (640KB) ( 437 )   Save BACKGROUND: Rare earth elements have some biological effects, and broad-spectrum anti-bacterial, anti-inflammatory and anti-virus capabilities, they can increase the bonding strength. OBJECTIVE: To introduce rare earth lanthanum into the implant coating, and to evaluate the biocompatibility of ultrasound-assisted micro-arc oxidation preparing the lanthanum biocoating. METHODS: Using ultrasound-assisted micro-arc oxidation, the biocoating containing lanthanum was prepared on the surface of the near β-type titanium alloy, and implanted in rabbit femur. The titanium alloy matrix and the micro-arc oxidation biocoating without lanthanum served as the control group. Optical microscope was used to observe the formation of new bone; Scanning electron microscopy was applied to observe the combination interface of implant and bone, and the bone residue after pulling the implant; the bone contact rate was statistically analyzed. RESULTS AND CONCLUSION: In the experimental group, the new bone formed surrounding the implant without any fibers and osteoclasts; Scanning electron microscopy and bone contact rate are the best in the experimental group and the worst in the titanium alloy group. This shows that ultrasound-assisted micro-arc oxidation preparing the lanthanum biocoating can achieve high osseointegration and good biocompatibility． Related Articles | Metrics

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Role of hyaluronic acid-modified chitosan composite scaffolds on wound healing of rats with cerebral cortex injury Song Xue-ming, Wu Chun-bo, Chen Zhi-qiang 2010, 14 (29):  5355-5359.  doi: 10.3969/j.issn.1673-8225.2010.29.009 Abstract ( 155 )   PDF (632KB) ( 443 )   Save BACKGROUND: In order to verify whether the hyaluronic acid-modified chitosan can serve as nerve scaffolds, the research group conducted in vivo test based on previous in vitro study. OBJECTIVE: To compare the biocompatibility and superiority of scar inhibition of hyaluronic acid-modified and poly-l-lysine modified chitosan scaffold, as well as pure chitosan scaffold in brain tissue. METHODS: Three kinds of scaffolds were implanted in the damage zone of rat cerebral cortex. At 3, 7, 14, 28, 56 days postoperation, brain tissues were harvested to undergo hematoxylin-eosin staining and immunohistochemistry. The inflammation, scar tissue formation and the growth of never cells in the implanted site were observed. RESULTS AND CONCLUSION: Each kind of scaffolds has a good biocompatibility with brain tissues. Hyaluronic acid modified chitosan scaffold showed lighter inflammation and less GFAP-positive cells around the scaffolds compared with other scaffolds. The differences were statistically significant (P < 0.01). Results showed that chitosan scaffolds of each group have a good biocompatibility. The hyaluronic acid modified chitosan scaffold is superior to others to inhibit scar formation and helps to the growth of nerve cells, and shows its superiority in tissue engineering. Related Articles | Metrics

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Preparation and biological degradation of chitosan tube stent Li Ya-xun, Chen Gang, Shi Wen-jun 2010, 14 (29):  5360-5362.  doi: 10.3969/j.issn.1673-8225.2010.29.010 Abstract ( 156 )   PDF (451KB) ( 455 )   Save BACKGROUND: Our previous studies have demonstrated that rejection and long-term complication occur in repairing esophagus defects using ilica gel or metal stents. Chitosan stent is prepared in order to find an ideal biological degradation stent and to observe its in vivo compatibility and degradation. OBJECTIVE: To explore the preparative method and biology characters of chitosan stents. METHODS: Initially, acetic acid solution was added into chitosan to get 60 g/L chitosan acetic acid hydrosol, and then, the tube was prepared by membrane making way and the chitosan was took off in sodium hydroxide. The tube with 5-mm inside diameter was cut into a 2-mm length segment and implanted into rats. Gross observation and light microscope were used to observe compatibility and degradation of chitosan tube. RESULTS AND CONCLUSION: The chitosan tube presented with smooth surface and good tenacity, which could be soften after absorbing water. The tube could be absorbed and degraded by tissues with time prolonged. It gives a new kind of way to prepare chitosan tube and approves the biological degradation. Related Articles | Metrics

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Biocompatibility and biomechanical properties of calcium phosphate bone cement treated by carbon nanotube Dong Wei-qiang, Bai Bo, Zhang Mei-jiang, Ye Jian-dong 2010, 14 (29):  5363-5366.  doi: 10.3969/j.issn.1673-8225.2010.29.011 Abstract ( 120 )   PDF (420KB) ( 452 )   Save BACKGROUND: Treatment for osteoporosis and bone defects needs a lot of bone repair materials. Calcium phosphate bone cement, as one of commonly used materials for bone repair, has great brittleness, so clinicians have been looking forward to develop a bone repair material with better biocompatibility and biomechanics. OBJECTIVE: To evaluate the biocompatibility and in vitro biomechanical properties of a new calcium phosphate bone cement treated by carbon nanotube. METHODS: In vitro hemolyxzation, cytotoxicity, acute systemic toxicity and hypersensitivity tests were performed on a new calcium phosphate cement according to the requirements given in Biological Standards for Implanted Biomaterials ISO 10993 by International Organization for Standardization. Thoracolumbar vertebral bodies (T12-L4) were harvested from six embalmed cadavers. The flexional compression fractures were experimented. After restoring the height of the vertebral bodies by the percutaneous kyphoplasty, the cement was respectively injected with calcium phosphate cement treated by carbon nanotube and common calcium phosphate cement. The extreme load, compressive strength, stiffness were obtained. RESULTS AND CONCLUSION: ① The hemolysis rate of the new cement-extracted solution in human was 1.81%, without hemolytic crisis. The cytotoxicity index of the 929 cell was graded as zero. The mouse acute systemic toxicity, mouse inherent toxicity and guinea-pig hypersensitivity were negative in extracting stock solution. ② After vertebroplasty, the extreme load, compressive strength and stiffness of calcium phosphate cement treated by carbon nanotube were significantly higher than those of common calcium phosphate cement. The biocompatibility of the new calcium phosphate cement treated by carbon nanotube is good enough to meet the requirements given in Biological Standards for Implanted Biomaterials by International Organization for Standardization, and the strength and stiffness of the new cement are better than common calcium phosphate cement. Related Articles | Metrics

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Preparation and biological characteristics of collagen-chitosan composite scaffold: Proportion of chitosan and collagen Wang Zheng, Ma Yun-sheng, Mu Chan-zheng, Wang Ya-guang 2010, 14 (29):  5367-5370.  doi: 10.3969/j.issn.1673-8225.2010.29.012 Abstract ( 76 )   PDF (450KB) ( 555 )   Save BACKGROUND: Chitosan and collagen scaffolds have been used as a common carrier material for tissue engineering. However, how to obtain an ideal cell carrier by adjusting the ratio between the two is still an unsolved problem. OBJECTIVE: To adjust the proportion of collagen and chitosan for complex scaffolds, to detect and compare biological properties of scaffolds prepared at various proportions. METHODS: Chitosan and type collagen protein were added by ratio 1:1, 1:2, 1:3, 1:4, 1:5. The materials were freeze-dried after UV cross-linking, then neutralized by NaOH and distilled water, followed by additional freeze-drying. The scaffolds at different proportions were observed for the properties, the degradation rate, the porosity, and swelling ratio. The size and distribution of the holes were detected under scanning electron microscopy. RESULTS AND CONCLUSION: At a fixed proportion of chitosan, there were significant differences in scaffold aperture by the statistical comparison (P < 0.05). The aperture diameter of the scaffold prepared at 1:3 ratio was the largest, (298.0±36.0) μm; the overall porosity was up to 93.9%-97.5%, the increasing ratio of collagen showed less impact on the porosity. The swelling rate reached about 80%, swelling degree of the scaffold was at an inverse proportion with the increase in the proportion of collagen. The degradation rate of the scaffold was increased with the increasing proportion of collagen. The higher chitosan concentration is, the slower degradation is. By means of UV cross-linking method, 1:3 ratio of collagen-chitosan scaffolds is more suitable for cartilage tissue engineering. Related Articles | Metrics

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Bioloading of amphiphilic chitosan derivatives and their sustained-release of triamcinolone acetonide acetate Zhou Huai-sheng, Lan Yu-qing, Cheng Liang-zheng, Zhang Li-ming, Yang Li-qun 2010, 14 (29):  5371-5374.  doi: 10.3969/j.issn.1673-8225.2010.29.013 Abstract ( 123 )   PDF (463KB) ( 478 )   Save BACKGROUND: Triamcinolone acetonide acetate (TAA) has strong anti-inflammatory effects as a long-acting corticosteroid. TAA has shown good results in the treatment of intraocular diseases in recent years, however, it also brings some side effects, and needs multiple injections to prevent disease recurring. Grafted chitosan, a copolymer, can generate nanoparticles in aqueous solution, and can be used as a drug carrier for extending the duration of drugs, reducing its side effects and improving its bioavailability. OBJECTIVE: To synthesize the amphiphilic chitosan derivative containing deoxycholic acid groups and to use it as a carrier to encapsulate TAA, to prepare drug-loading nanoparticles of sustained-release function, and to study the load and performance of sustained-release TAA. METHODS: The amphiphilic chitosan derivative was synthesized through amidation reaction. Morphology and particle size of nanoparticles were observed by transmission electron microscopy, Zeta potential of nanoparticles was measured by Zeta potential analyzer. The entrapment efficiency, drug loading and in vitro drug release properties of TAA-loaded chitosan-deoxycholic acid nanoparticles were determined by in vitro release assay. RESULTS AND CONCLUSION: The synthesized amphiphilic chitosan derivatives containing TAA could form drug-loaded nanoparticles, of which drug loading content was 82%. With the increasing drug loading content, the particle sizes of drug-loaded nanoparticles increased, while their Zeta potential values decreased. The result of in vitro release assay indicated that the drug-loaded nanoparticles constantly released TAA in a sustained manner within 72 hours. The drug-loaded nanoparticles based on the amphiphilic chitosan derivative exhibited a sustained-release behavior and is potential to increase the therapeutic effect of TAA. Related Articles | Metrics

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A new type of bone internal fixation polymer: Synthesis and property evaluation of unsaturated polyester amide resin Xiao Sheng, Ai Yong-ping, Xie Shi-kun, Yi Rong-xi, Zheng Xiao-qiu, Liu Xiao-fei, Zeng Guang-xu 2010, 14 (29):  5375-5378.  doi: 10.3969/j.issn.1673-8225.2010.29.014 Abstract ( 145 )   PDF (404KB) ( 335 )   Save BACKGROUND: High strength, high modulus controllable degradable and absorbable internal fixation bone substitutes the metal implant which is currently clinically used and present with biological stability, thus avoiding the metal implant from inflammation, too high elastic modulus, and requirement to perform secondary operation. OBJECTIVE: To synthesize unsaturated polyester amide resin and to observe the influence of various initiator-accelerants on its initial setting time at room temperature, as well as polymer mechanics and degradation properties after cross-linking. METHODS: Using maleic anhydride, phthalic anhydride, ethylene glycol, 1,2-propanediol, neopentyl glycol, caprolactam, unsaturated polyester amide resin prepolymer was synthesized with melt polycondensation method, and was then characterized. Using vinyl acetate as the cross-linking agent, adding a certain amount of initiator-accelerants for pre-crosslinking agent at room temperature, followed by heat treatment, the high-strength, fully degradable polyester amide polymer was deeply cross-linked. The influence of various initiator-accelerants on initial setting time of unsaturated polyester amide resin at room temperature, as well as polymer mechanics and degradation properties after cross-linking, were observed. RESULTS AND CONCLUSION: The synthesized, unsaturated polyester amide resin oligomer has a good performance, which can meet the requirement of cross-linking; different types of initiator-accelerants exhibited various impacts on the gel time of unsaturated polyester amide resin pre-crosslinking at room temperature. The mechanism underlying crosslinking was different; Following the heat treatment of the deep cross-linking, resin ionomer degraded in simulated body fluid, indicating good mechanical strength retention capacity. Preliminary results show that this material can be developed into a fully degradable bone internal fixation material. Related Articles | Metrics

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Effect of fibrin glue loaded exogenous vascular endothelial growth factor on the motor function of rats with sciatic nerve injury Yu Ying-jian, Cao Rui-zhi, Liu Heng, Li Gui-tao, Mu Tian-wang, Hu Ming-yun 2010, 14 (29):  5379-5382.  doi: 10.3969/j.issn.1673-8225.2010.29.015 Abstract ( 99 )   PDF (447KB) ( 341 )   Save BACKGROUND: There are various methods for repair sciatic nerve injury, however, the recovery of nerve function is not satisfactory due to complexity of sciatic nerve anatomy and function. OBJECTIVE: To investigate the effects on functional outcome of the injured sciatic nerve using exogenous vascular endothelial growth factor (VEGF) mixed with fibrin glue as a carrier. METHODS: The sciatic nerve injury model was made by cutting off the left sciatic nerve of Wistar rats and suturing in normal position. The successful model rats were randomly into two groups. Experimental group was injected with VEGF/fibrin glue complex via adventitia at the site of cutting off sciatic nerve. Control group was injected with VEGF165 plasmid. Sciatic-nerve function index, motor nerve conduction velocity and gross appearance were performed at 4, 8, 12 weeks after medication. RESULTS AND CONCLUSION: The primary healing of wound was found in animals of two groups. At 1 week after treatment, 6 rats of the experimental group appeared foot ulcers and muscle atrophy; five rats of the control group showed foot ulcers. In the experimental group, fibrin gel almost absorbed at 4 weeks, completely absorbed at 8 weeks, normal nerve appearance was found at 12 weeks. In the control group, nerve showed mild congestion and edema at 4 weeks, the edema disappeared and the nerve slightly adhered on surrounding tissues at 8 weeks, the scars formed surrounding nerves at 12 weeks. At 4 and 8 weeks in the experimental group, nerve function index and nerve conduction velocity were lower than the control group (P < 0.05), with no statistical difference at 12 weeks (P > 0.05). These results indicate that fibrin glue can be used as a carrier for VEGF, fibrin glue carrying VEGF can enhance neurological structural and functional recovery of the injured nerve. Related Articles | Metrics

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Influence of non-precious porcelain alloys on bond strength of restorative composite resins after intra-oral sandblasting Qiu Jing, Chen Ya-ming, Feng Li-jun 2010, 14 (29):  5383-5386.  doi: 10.3969/j.issn.1673-8225.2010.29.016 Abstract ( 128 )   PDF (459KB) ( 520 )   Save BACKGROUND: Several researches have studied the surface treatment and resin bond strength on the fractured porcelain surface. However, clinical observations show that most of the porcelain fractured cases are more or less exposed in the metal substrates, and there are little studies about surface treatment and resin bond strength on the widely used non-precious metal substrates, which include nickel-chromium (Ni-Cr) and cobalt-chromium (Co-Cr) alloys. OBJECTIVE: To study the surface roughness and the bond strength of non-precious porcelain alloys and restorative composite resins after intra-oral sandblasting. METHODS: Ni-Cr alloy specimens and Co-Cr alloy specimens were fabricated and randomly divided into 4 groups: Ni-Cr group, Ni-Cr sandblasted group, Co-Cr group, Co-Cr sandblasted group. Subsequent to intra-oral sandblasting, the surface roughness of specimens in each group was measured. Using Clearfil Repair kits, specimens’ surfaces were bonded to restorative composite resin cylinders. After specimens were stored at 37℃ in distilled water for 24 hours, shear bond strengths were measured and fracture surfaces were visually analyzed using the stereomicroscope and scanning electron microscopy. RESULTS: Ni-Cr sandblasted group and Co-Cr sandblasted group showed significant higher surface roughness and shear bond strength than Ni-Cr group and Co-Cr group respectively (P < 0.05). Under the stereomicroscope, all specimens of Ni-Cr group and Co-Cr group revealed adhesive failures, whereas majority of Ni-Cr sandblasted group and Co-Cr sandblasted group revealed adhesive failures and minority of them revealed combination failures. Scanning electron microscopy images showed that resin-metal fracture surfaces of Ni-Cr group and Co-Cr group had few remnants of composite resin, and those of Ni-Cr sandblasted group and Co-Cr sandblasted group had lots of small embedded remnants of composite resin. Intra-oral sandblasting could enhance the surface roughness and shear bond strength of non-precious porcelain alloys and restorative composite resins. Related Articles | Metrics

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Relationship between fatigue strength of complete denture and denture materials Xiao Yue, Zhang Chi, Zhu Jian-hua, Yan Zhao-ping,Du Ying 2010, 14 (29):  5387-5390.  doi: 10.3969/j.issn.1673-8225.2010.29.017 Abstract ( 119 )   PDF (366KB) ( 310 )   Save BACKGROUND: The complete denture is a common repair form of prosthodontics clinical work, but the early fracture on the middle plate of complete denture is an important factor influencing the life of complete denture. OBJECTIVE: To analyze the early failure of complete denture from a view of the mechanics. METHODS: Based on the stress analysis, structural analysis, material property analysis of the plate, the real cause of early failure in the middle section was identified, thus proposing a new proposal to solve early fracture, improve fatigue strength of complete denture, and extend the service life of complete denture. RESULTS AND CONCLUSIONS: The existing plastic manufacturing complete denture of high quality and high fatigue strength was superior to plate skeleton complete denture made of alloy steel or cast steel in the following aspects: ① prolonging the service life (generally permanent life is not available); ② reducing prices by 100% or lower; ③ comforting due to small quality. Related Articles | Metrics

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Influence of polyurethane sealant on shear bond strength of ceramic and dentin Liang Feng-lin, Chen Xiang-tao, Liu Yan-li, Li Jin-xian, Chen Lin 2010, 14 (29):  5391-5394.  doi: 10.3969/j.issn.1673-8225.2010.29.018 Abstract ( 128 )   PDF (504KB) ( 269 )   Save BACKGROUND: Polyurethane sealant system has been developed in recent years as newly adhesive materials in medical field, it has strong bonding property with many medical materials. However, studies on stomatology are few. OBJECTIVE: To evaluate the effectiveness of polyurethane sealant on shear bond strength between glass ceramic and human dentin. METHODS: Freshly extracted non-carious human premolars were collected to prepare flat mesial and distal dentin surface with diamond bur. Totally 48 ceramic discs (3 mm in diameter, 3 mm in height) were fabricated and then cementated on dentin bonding surface using polyurethane sealant, Variolink Ⅱ and Panavia F, respectively. Eight specimens in each group were stored in 37 ℃ water for 24 hours, directly receiving shearing test, while the other 8 specimens in each group were additionally thermocycled for 500 times before shear bond strength test. The treated dentin surface was examined with scanning electronic microscopy. RESULTS AND CONCLUSION: Polyurethane group showed the highest bond strength before thermocycling, then Variolink Ⅱ group and Panavia F group the lowest. Group C had the lowest bond strength. After thermocycling, polyurethane group showed the highest bond strength before thermocycling, then Variolink Ⅱ group, and Panavia F group the lowest bond strength. The bond strength of all groups significantly decreased after thermocycling (P < 0.05). Scanning electron microscopy observation revealed that resin tags were not obvious on the interface between dentin and medical polyurethane sealant, while the formation of resin tags could be easily defected on the interfaces between dentin and other two resin cements. The polyurethane sealant has a higher bond strength to dentin than those based on self-etch bonding system and etch-rinsing resin cements. Related Articles | Metrics

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Preparation and surface morphology analysis of submicron nano-hydroxyapatite/poly L-lactic acid composites Du Jiang-hua, Li Dan, Han Feng-lan, Yang Qing-fang 2010, 14 (29):  5395-5398.  doi: 10.3969/j.issn.1673-8225.2010.29.019 Abstract ( 87 )   PDF (502KB) ( 376 )   Save BACKGROUND: Nano-hydroxyapatite (HA)/poly L-lactic acid (PLLA) composites as scaffold material in bone tissue engineering have good biocompatibility. However, HA is characterized by easy agglomeration and hard equably dispersed in materials, the combination between inorganic particle and organic high polymer is affected.  OBJECTIVE: To prepare HA/PLLA composite, and study the effect of PLLA solution, the disperser time of HA, the content of HA on dispersion, and analyze the surface appearance, the cross section and the interface of HA/PLLA composites. METHODS: Sub-micron HA/PLLA composites was prepared by the method of the solution blending, submicron HA powder was dispersed into the chloroform solution of PLLA with the aid of the ultrasonic wave, and then the mixed system was dried under the natural condition to remove the solvent, finally the submicron HA/PLLA compound materials was obtained. The effect of the solution concentration on dispersion HA in solution was discussed. The cross section of composites and interface were analyzed by the Fourier transform infrared spectroscopy and the scanning electron microscopy. RESULTS AND CONCLUSION: When the mass ratio of sub-micron HA to PLLA was 0.15: 1 and dispersing time HA in PLLA solution exceeded 30 minutes. PLLA solution 0.14 kg/L can make HA good dispersity in PLLA. When sub-micron HA content exceeds 15%, it will produce reunion in composite materials. Infrared analysis shows that characteristic functional groups from HA/PLLA composites have no change. The results suggest that: sub-micron HA can be mixed well with PLLA by ultrasonic oscillation, which would improve the interface of sub-micron HA/PLLA composites. Related Articles | Metrics

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Ahmed glaucoma valve implantation in the treatment of refractory glaucoma: Complication and biocompatibility Zhang Lei, Wang Qiang, Lei Ning-yu 2010, 14 (29):  5399-5402.  doi: 10.3969/j.issn.1673-8225.2010.29.020 Abstract ( 118 )   PDF (360KB) ( 351 )   Save BACKGROUND: In recent years, the emergence of aqueous drainage has achieved good results in the treatment of refractory glaucoma, but some complications related to the materials may occur after implantation, such as the inflammatory reaction leads to reduced formation of aqueous humor, thus resulting in low intraocular pressure and shallow anterior chamber. OBJECTIVE: To evaluate the therapeutic effect and biocompatibility of Ahmed glaucoma valve implantation for refractory glaucoma. METHODS: Thirty-two cases (32 eyes) with refractory glaucoma underwent Ahmed glaucoma valve implantation, including 12 cases of neovascular glaucoma, 6 cases of aphakic glaucoma, 4 cases of uvetic glaucoma, 4 cases of traumatic glaucoma and 6 cases of failed filtering operation. The follow-up period was 6-24 months. RESULTS AND CONCLUSION: The preoperative intraocular pressure was 4.655-9.044 kPa with the average of (5.61±     1.29) kPa. After the operation, the average level of intraocular pressure was (2.85±1.16) mmHg at the last follow-up visit. The total success rate was 84.38%, including 83.3% for neovascular glaucoma and 85% for the others. The visual acuity was improved in 10 eyes at different levels with the best visual acuity of 0.3. The common postoperative complications included transient ocular hypotension in 6 cases, shallow of anterior chamber in 6 cases, hyphema in 4 cases, obstruction of the inflow tube in 3 cases. The complications were improved after symptomatic treatment. Ahmed glaucoma valve implantation is a safe and effective method for reducing the intraocular pressure, but the complication incidence is increasing, which may be result from the insufficiency of drainage device design and materials. Related Articles | Metrics

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Kinesitherapy in combination with sodium hyaluronate injected into the articular cavity for the treatment of acetabular dysplastic coxarthrosis Wang Li-he 2010, 14 (29):  5403-5406.  doi: 10.3969/j.issn.1673-8225.2010.29.021 Abstract ( 136 )   PDF (446KB) ( 855 )   Save BACKGROUND: Artificial joint replacement is not the best choice for younger patients and patients with early and middle stage of acetabular dysplastic coxarthrosis. Sodium hyaluronate lubricates joints, nourishes and promotes healing and regeneration of the articular cartilage. It can inhibit the degeneration of cartilage when the cartilage early damage and osteoarthritis form. OBJECTIVE: To verify the clinical efficacy of kinesitherapy in combination with sodium hyaluronate injected into the articular cavity in the treatment of acetabular dysplastic coxarthrosis. METHODS: Thirty-eight patients with acetabular dysplastic coxarthrosis were randomly divided into an experimental group (n=20) receiving therapeutic exercise combined with sodium hyaluronate treatment, and a control group (n=18) undergoing comprehensive physical therapy only. The patient’s hip joint function was evaluated by Harris hip scoring and the clinical efficacy was assessed before and after one course of treatment. RESULTS AND CONCLUSION: The Harris hip scoring of the experimental group ranged from preoperative (48.8±8.4) points to postoperative (90.6±5.2) points. The remarkable effective rate was 90.0%. The Harris hip scoring of the control group ranged from preoperative (49.6±9.3) points to postoperative (76.2±4.8) points. The remarkable effective rate was 50.0%. There was a significant difference in Harris hip scoring and remarkable effective rate between two groups (P < 0.05). Kinesitherapy in combination with sodium hyaluronate is efficacious in improving joint function of acetabular dysplastic coxarthrosis patients. Related Articles | Metrics

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Coronary stent restenosis and glycated hemoglobin following coronary stent implantation Shi Yong 2010, 14 (29):  5407-5410.  doi: 10.3969/j.issn.1673-8225.2010.29.022 Abstract ( 229 )   PDF (378KB) ( 420 )   Save BACKGROUND: Basic and clinical studies have shown that many factors are involved in stent restenosis. In-stent restenosis is correlated with stent, and smoking, diabetes and unstable angina are also important predictors. Glycated hemoglobin is the monitor index of diabetes and biomarker of cardiovascular disease. OBJECTIVE: To evaluate coronary stent plant in-stent restenosis after implantation, and the relationship between glycated hemoglobin. METHODS: A total of 36 patients with successful coronary stenting received atherosclerotic heart disease, were divided into 3 groups according to the level of glycated hemoglobin and fasting blood glucose: normal glycosylated hemoglobin and fasting blood sugar group (n = 11), normal glycosylated hemoglobin and elevated fasting glucose group (n = 15), increased glycosylated hemoglobin and fasting blood glucose group (n = 10). Because of chest pain after stent implantation in patients with recurrent or routine follow-up coronary angiography, the original target lesion ≥ 50% luminal diameter stenosis was in-stent restenosis in the control of glycosylated hemoglobin on coronary artery restenosis. RESULTS AND CONCLUSION: Of 36 patients, 7 cases had coronary artery restenosis, accounting for 19%, including 1 in normal glycosylated hemoglobin and fasting blood sugar group, 2 in normal glycosylated hemoglobin and elevated fasting glucose group and 4 in increased glycosylated hemoglobin and fasting blood glucose group. Glycosylated hemoglobin and fasting plasma glucose were greater in increased glycosylated hemoglobin and fasting blood glucose group compared with the other two groups (P < 0.05). The regression analysis showed that glycosylated hemoglobin is one important factor for restenosis following a coronary stent. Glycosylated hemoglobin measurement can further  assess the coronary risk of restenosis after stent implantation. Related Articles | Metrics

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Application of nano artificial skin and its materials in burn wounds Zhong Yong-fu, Liu Hua, Xu Zhi-nan, Yang Xiao-chun 2010, 14 (29):  5411-5414.  doi: 10.3969/j.issn.1673-8225.2010.29.023 Abstract ( 150 )   PDF (691KB) ( 573 )   Save OBJECTIVE: To evaluate the types and characteristics of existing nanometer artificial skin and materials, as well as the application and development prospects in burn wounds. METHODS: A computer search was performed in Wanfang database (http://www.wanfangdata.com.cn/) between January 1999 and December 2009 to retrieve articles of nanometer artificial skin and materials applied in burn wound, using key words of “nanotechnology, artificial materials, burn wound” in Chinese. After the repeated study, general review or Meta analysis were excluded, 24 articles were screened into the evaluation. RESULTS: At present, nano-dressings for skin repair are mainly keratinocyte growth factor, bacterial cellulose, nano-silver and chitosan nano-particles, etc. According to the principles of size effect and surface effect, a variety of nanometer skin dressings can achieve better adhesion, effectively prevent the bleeding wound and infection, reduce pain, and accelerate wound healing. Nano-silver is most used in clinical application and fastest growing. Nano-silver compound with other materials is also under exploring ways and has obtained some success. Meanwhile, a series of problems regarding nano-materials repair burn wound, such as security, stability, uniformity and productivity, are also paid attention, it is one of the current hotspot of related studies. CONCLUSION: The nanometer dressing, with various types, good efficacy and low adverse events, is an ideal medication type of burn wounds, being worth further study. Related Articles | Metrics

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Material characteristics of polypropylene sling and its application in stress urinary incontinence Li Li 2010, 14 (29):  5415-5418.  doi: 10.3969/j.issn.1673-8225.2010.29.024 Abstract ( 140 )   PDF (715KB) ( 430 )   Save OBJECTIVE: To evaluate the material characteristics of polypropylene sling and its application in stress urinary incontinence, to find a reasonable sling material and an appropriate surgical approach. METHODS: Using “polypropylene, polypropylene sling, stress urinary incontinence” in Chinese as the key words, a computer search was performed for 52 relevant articles published between February 2003 and February 2010. Articles related to polypropylene sling material and stress urinary incontinence were included; repeated study or Meta analysis articles were excluded. Totally 22 literatures focused the material characteristics of polypropylene sling and its application for stress urinary incontinence. RESULTS: The treatment of stress urinary incontinence using sling has developed rapidly in recent years. Polypropylene sling materials are generally divided into three categories according to the source and properties: sterile polypropylene mesh sling, self-made polypropylene mesh sling, autologous fascia vaginal sling. So far, no erosion or infection occurs by using polypropylene sling. However, the size of sling, weaving method, sling fiber surface treatment, surgical approach and fixation after sling implantation which all influence the postoperative quality need further research. CONCLUSION: Polypropylene sling can be used as an ideal scaffold material for stress urinary incontinence. Related Articles | Metrics

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Biocompatibility and clinical application of ureteral stent Jia Shu-lei, Yu De-kai, Yang Dong 2010, 14 (29):  5419-5422.  doi: 10.3969/j.issn.1673-8225.2010.29.025 Abstract ( 113 )   PDF (605KB) ( 991 )   Save OBJECTIVE: To summarize the biocompatibility and clinical applications of ureteral stent in recent years. METHODS: A computer search was performed by the author in the VIP database to retrieve articles about ureteral stent materials. The search time limit was 1998-01/2010-04. Key words are ureter; stent material; double-J tube in Chinese. Inclusion criteria: ① articles related to ureteral stent biocompatibility; ② application of ureteral stent and the resulting side effects. Exclusion criteria: repeated studies or old literatures. According to the inclusion and exclusion criteria, 28 literatures were retained. RESULTS: The most common biological material currently used in ureteral stents, is the synthetic polymer, but with more complications and poor biocompatibility. Metal ureteral stent is expensive and difficult to remove after implantation, prone to stent displacement. Biodegradable ureteral stent can effectively maintain the drainage patency, low complication rate, be safe and good biocompatible, it is still in the stage of basic research. Clinically, stent materials should be selected for the placement according to patients’ disease. The operation should be strict for stent implantation, symptomatic treatment should be given when complications occur, to prevent complications. CONCLUSION: The biocompatibility of ureteral stents is needed to be improved; ureteral stent is simple and effective, the patient is well tolerated, but it is necessary to understand and prevent the stent complications after implantation. Related Articles | Metrics

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Friction properties of different dental restorative materials and their influential factors Gong Lei, Xiao Hong 2010, 14 (29):  5423-5426.  doi: 10.3969/j.issn.1673-8225.2010.29.026 Abstract ( 116 )   PDF (580KB) ( 740 )   Save OBJECTIVE: To analyze the friction mechanism of dental restorative materials and their influencing factors. METHODS: Using “dental materials, ceramics, friction properties, wear resistance, influencing factor, friction mechanism” in Chinese and “dental materials, ceramics, friction performance, wear, factors, friction mechanism” in English as the key words, a computer search was performed in Pubmed database (http://www.ncbi.nlm.nih.gov/PubMed) and VIP database (http://www.cqvip.com/) between January 1993 and October 2009 for articles about the friction properties of dental restorative materials; repeated study, review or Meta analysis were excluded. Totally 21 articles mainly focus on the friction mechanism of dental restorative materials and its influencing factors. RESULTS: The ideal dental restorative materials should have similar with but slightly lower friction properties than natural teeth. As the complexity of chewing process and the diversity of dental restorative materials, the wear resistance of dental materials is affected by many factors, therefore dental ceramic materials, dental metal materials and dental resin materials were investigated to understand the wear properties of natural teeth, dental ceramics materials, dental metal materials, dental resin materials, to select matched dental restorative materials and to prevent excessive wear of natural teeth. CONCLUSION: An understanding of friction and wear properties of dental restorative materials such as dental ceramic materials, dental metal materials, and dental resin materials, can not only help doctors choose the matching restorative materials according to the individual conditions of patients, achieve the optimal repair results, but also help to develop a more rational, more durable dental restorative material. Related Articles | Metrics

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Material features and clinical application of artificial anal sphincter Liu Li-bing 2010, 14 (29):  5427-5430.  doi: 10.3969/j.issn.1673-8225.2010.29.027 Abstract ( 89 )   PDF (629KB) ( 528 )   Save BACKGROUND: Severe anal incontinence is caused by various factors and greatly affects survival and life quality of patients. Efforts have been attempted to control incontinence and restore anal function. In particular, reconstruction by operation or muscle replacement for anal sphincter has been performed. However, the effect is not favorable. OBJECTIVE: To explore the material features and clinical application of artificial anal sphincter. METHODS: A computer-based online search of Pubmed database (http://www. ncbi.nlm.nih.gov/pubmed/) and Wanfang database (http://www.wanfangdata.com.cn) was performed for articles published between January 1991 and December 2009 related to artificial anal sphincter, material features of artificial anal sphincter and life quality following treatment, with the key words “anal sphincter, fecal incontinence” in English and “anal sphincter, enteroproctia, anal incontinence” in Chinese. Repetitive and outdated studies were excluded. Finally, 22 articles were included. RESULTS AND CONCLUSION: Ideal artificial anal sphincter should have good biocompatibility, and minimize intestine inflammation. Similar to dynamic gracilis transposition, artificial anal sphincter is placed around original position through tunnel, which maintains certain pressure and recovers through hand pump localized at scrotum or labia. The effect of artificial anal sphincter on treating severe anal incontinence is positive. Related Articles | Metrics

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Oviductal contraception and subcutaneous implantation of slow-release contraceptive drugs Wang Fang, Mao Xi-guang 2010, 14 (29):  5431-5434.  doi: 10.3969/j.issn.1673-8225.2010.29.028 Abstract ( 103 )   PDF (659KB) ( 497 )   Save OBJECTIVE: To explore the contraceptive effect of new reversible contraceptive device on oviduct and side effects caused by subcutaneous implants of controlled-release contraceptive drugs. METHODS: A computer search was performed by the first author among Wanfang database (http://med.wanfangdata.com/) for articles about oviductal contraception and subcutaneous implantation of controlled-release contraceptive drugs. The retrieval time was 1998-01/2010-04. Key words are contraceptive device on oviduct; subcutaneous implants; slow-release contraceptive drugs. Totally 23 literatures were selected for further analysis. RESULTS: The contraceptive device on oviduct made of nickel titanium alloy, polyethylene and other polymer materials, are safe and well histocompatible, present with a smooth placing, well positioned and easy dislodge. Subcutaneous implants for contraception is an efficient, long-lasting, safe, simple, reversible method, which is deeply welcomed by the women at reproductive age, with less breakage upon dislodging. However, further studies are needed to determine side effects. CONCLUSION: With the continuous development of new materials and techniques, it is an increasing requirement to produce excellent contraceptive system, with less side effects, so as to achieve better outcome in clinical application. Related Articles | Metrics

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LARS artificial ligament in arthroscopic cruciate ligament reconstruction following exercise injury Lu Jian-qing, Li Dong, Shen Yuan-sheng 2010, 14 (29):  5435-5438.  doi: 10.3969/j.issn.1673-8225.2010.29.029 Abstract ( 102 )   PDF (589KB) ( 492 )   Save OBJECTIVE: To explore the operative effect on arthroscopic reconstruction of anterior and posterior cruciate ligament in knee joint using ligament advanced reinforcement system (LARS) artificial ligament. METHODS: A computer search was performed by the first author on VIP database (http://www.cqvip.com/) for articles about cruciate ligament reconstruction using LARS artificial ligament. The search time limit is 2000-01/2009-12. Key words are arthroscopy, LARS artificial ligament, reconstruction, anterior cruciate ligament, posterior cruciate ligament in Chinese. After the first trial, each article citation was looked over. According to inclusion and exclusion criteria, 27 literatures were retained. RESULTS: Artificial ligament has been improved for a long history, definitive clinical effect only emerges, in recent decade years. Analysis on the LARS artificial ligament effect shows that, most of them have a good clinical efficacy within short and medium term, and the complications are rare, especially acute synovitis is free of the report, but long-term effects can not be determined. CONCLUSION: Arthroscopic reconstruction of posterior cruciate ligament using LARS artificial ligaments can leads to a good anatomic reconstruction and knee stability; as for young patients who require rapid recovery, especially anterior athletes with cruciate ligament injury, LARS artificial ligament is an ideal and safe graft material. Related Articles | Metrics

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Nerve conduit biomaterials repair peripheral nerve injury in animal experiments Yang Hua-lin 2010, 14 (29):  5439-5442.  doi: 10.3969/j.issn.1673-8225.2010.29.030 Abstract ( 97 )   PDF (690KB) ( 417 )   Save OBJECTIVE: To observe and determine the degree of regenerated nerve functional recovery and the number of nerve regeneration in animal experiments of nerve conduit biomaterials transplantation. METHODS: A computer search was performed in the Chinese Journal Full-test database between 1996 and 2010, using key words of “nerve conduit, nerve injury, conduit materials, biomaterials” in Chinese. Animal experiments of the nerve conduit material in repair of peripheral nerve injury were included. RESULTS: Any of the existing materials are not sufficient to prepare ideal nerve conduit. Under the premise of the biodegradation, natural materials often have better biocompatibility, and synthetic polymers can regulate the degradation time, as well as mechanical and physical properties of the of materials through the modulation of the ratio of components, the molecular weight and molecular weight distribution. Ideal nerve conduit for peripheral nerve repair should select the appropriate biomaterials and assembly techniques, to prepare a conduit with good physical properties (permeability, flexibility, degradation and so on), permeability and flexibility are more important for large nerve defects. CONCLUSION: The single-chamber hollow conduit filled various materials can promote neural regeneration, combination of several different filling materials may be more beneficial to nerve repair. Related Articles | Metrics

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Types and material characteristics of cerebral vascular stent and complement reaction after stenting Qiu Xiao-feng 2010, 14 (29):  5443-5446.  doi: 10.3969/j.issn.1673-8225.2010.29.031 Abstract ( 131 )   PDF (611KB) ( 456 )   Save OBJECTIVE: To explore the material characteristics of cerebral vascular stents, and the correlation between complement reactions and complications after stenting. METHODS: Using “cerebral vascular stents, biomaterials, biocompatibility, restenosis, complement reaction” as the Chinese key words, “rebrovascular disease, stent, therapy, complement” as the English key words, a computer search was conducted on Pubmed database (http://www.ncbi.nlm.nih.gov/PubMed) and the VIP database (http://www.cqvip.com/) from January 2000 to December 2008 for articles about the characteristics of cerebral vascular stents and complement reaction after stent implantation; repeated study and Meta analysis articles were excluded. Totally 24 articles mainly focus on the material science characteristics of cerebral vascular stent and the correlation between complement reactions and complications after stenting. RESULTS: The metallic stents have poor biocompatibility while polymer stents, coated stents and drug stents are present with better biocompatibility. Cerebral vascular stents, as an important means of the treatment of intracranial and extracranial vascular disease, it can reduce ischemic stroke risk in patients with intracranial and extracranial artery stenosis, but the complications after stenting such as restenosis, may seriously impede further development of the technology, immune inflammatory response play an important role in ischemic brain injury mechanisms and the biomaterials also has significant impact on the complement system. CONCLUSION: Using the appropriate biomedical materials, cerebrovascular stent placement can significantly reduce the mortality rate of cerebrovascular disease. But the complications occur during and after the process of vascular stent placement, should be paid attention and given positive control measures. Development of new biomedical materials, and simultaneous detection of the complement system-related indicators, will increase the success rate of cerebral vascular stent. Related Articles | Metrics

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Material characteristics, re-endothelialization and late stent thrombosis of drug eluting stent Peng Feng-lin 2010, 14 (29):  5447-5450.  doi: 10.3969/j.issn.1673-8225.2010.29.032 Abstract ( 207 )   PDF (622KB) ( 571 )   Save OBJECTIVE: To evaluate the difference and mechanisms underlying the re-endothelialization and late stent thrombosis in different types of drug eluting stents, to explore the research and development direction of new drug eluting stent. METHODS: A computer-based online search was performed for articles published from January 1993 to April 2010 with the key words of “intravascular stent, re-endothelialization, drug eluting stent, late stent thrombus” in English and Chinese. Studies regarding re-endothelialization and late stent thrombus of drug eluting stent were included. The repetitiveness or Meta papers were excluded. Totally 33 articles mainly focus the difference and mechanisms underlying the re-endothelialization and late stent thrombosis in different types of drug eluting stents. RESULTS: Re-endothelialization is different in several kinds of drug eluting stents. Vascular smooth muscle cell antiproliferative drug eluting stents are widely used in the clinical practice, but the delayed endothelialization may lead to late thrombosis, thereby affecting the clinical efficacy and application. Other kinds of drugs eluting stent exhibited higher restenosis rate than vascular smooth muscle cell antiproliferative drug eluting stents. To solve incomplete stent endothelialization of drug eluting stent is a key issue of improving drug stent. CONCLUSION: Ideal coating drugs can effectively inhibit vascular intimal hyperplasia, but also induce vascular endothelium to well cover stent, thus preventing the emergence of late thrombosis. Related Articles | Metrics

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Drug-eluting stent: Evaluation of safety, short- and long-term effect Liu Zhang-qi, Li Chun-liang 2010, 14 (29):  5451-5454.  doi: 10.3969/j.issn.1673-8225.2010.29.033 Abstract ( 109 )   PDF (649KB) ( 428 )   Save OBJECTIVE: To evaluate the effect and safety of drug-eluting stent implantation in coronary artery interventional therapy. METHODS: With key words “percutaneous transcoronary angioplasty, drug intravascular stent, intimal hyperplasy, restenosis, biocompatibility”, a computer-based online search was performed for articles published between January 2000 and December 2009. Articles correlated with intravascular stent materials, intravascular stent material modification were included. Repetitive studies or Meta analysis was excluded. Finally, 14 articles were included, and influence of drug-eluting stent on blood vessel endothelium hyperplasy, restenosis, and biocompatibility was discussed. RESULTS: Drug-eluting stent can control release of drug from polymer coating to vascular lesion sites by eluting pattern. For example, rapamycin-eluting stent effectively reduces incidence of restenosis and cardiovascular events in treating coronary atherosclerotic heart disease, and displays favorable effects in treating diabetes, small vessel disease, coronary artery long lesions and diffuse complex lesion. In addition, domestic rapamycin-eluting stent shows safety compared with foreign stent. However, it has been paid attention whether the interaction of drug-eluted by the stent and the coating can induce thrombus in the stent. Researchers have studied the thrombus mechanism at late stage, intervention of thrombus risks and stent technology to explore safe drug-eluting stent that can reduce restenosis and in-stent thrombus. CONCLUSION: Drug-eluting stent, such as rapamycin-eluting stent, effectively reduces incidence of restenosis and cardiovascular events in treating coronary atherosclerotic heart disease, with safety and short- and long-term effect. Related Articles | Metrics

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Application of biomaterials and biomechanical characteristics of ankle injuries Guo Jian-yin 2010, 14 (29):  5455-5458.  doi: 10.3969/j.issn.1673-8225.2010.29.034 Abstract ( 67 )   PDF (668KB) ( 596 )   Save OBJECTIVE: To investigate the biomechanical characteristics of ankle joint injury and biomaterial intervention treatment, to classify and summarize the treatment means and mechanisms after ankle joint injury. METHODS: A computer search was conducted on PubMed database (http://www.ncbi.nlm.nih.gov/PubMed) from 1998 to 2007 and CNKI Database (www.cnki.net / index.htm) from 2003 to 2009, using “ankle joint, injury, biological materials, treatment” in English and in Chinese as key words in the title and summary. Articles about ankle joint injury, treatment, material science characteristics and biocompatibility were included, totally 22 articles. RESULTS: The ankle joint is the bounce starter of human body, also the landing buffer unit. Ankle ligament injury is common because of several internal and external factors in exercise. Currently ankle ligament rehabilitation therapy is physical therapy and surgical repair, or a combination treatment of the two. With the advances of modern medicine, the biomaterial intervention of tendon healing is developing. CONCLUSION: Because the ankle joint is a weight-bearing joint, bearing large violence, and other factors such as complex stress, ankle joint requires a high ligament function, which is a potential problem of applying biomaterials on ankle ligament injury rehabilitation. Current researches have achieved good results in simulating the function of autologous ligament through many tries such as ligament material selection, processing and surface modification. With the advancement of cell biology, molecular biology methods and technologies, as well as the use of gene therapy, the studies on the repair of tendon ligament injury will enter a new phase, also provides possibility and evidence for proper use of biomaterials for ankle ligament. Related Articles | Metrics

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Drug release properties of chitosan and other biological materials as insulin carriers Bu Rui-fang 2010, 14 (29):  5459-5462.  doi: 10.3969/j.issn.1673-8225.2010.29.035 Abstract ( 211 )   PDF (531KB) ( 425 )   Save OBJECTIVE: To investigate the drug release properties of chitosan and other biological materials as a carrier of the insulin. METHODS: A total of 19 articles published between 1999 and 2008, are Chinese experimental study focusing on the release and hypoglycemic effect of chitosan and other biological materials as a carrier of insulin. The literatures were analyzed according to the chitosan insulin carrier materials, experimental methods, experimental results, experimental conclusions, to evaluate the release and the hypoglycemic effect. Meanwhile, other biological materials as the carrier of insulin were comprehensively analyzed by carrier type, preparation principle, in vitro drug release, and hypoglycemic effect. RESULTS: Thirteen literatures were selected from fifteen experimental studies addressing chitosan insulin carriers. Analysis showed that some chitosan, as a carrier, are present with pH-responsive drug release, which can be modulated by pH value at different parts of gastrointestinal tract, thus reducing damage of oral insulin in the gastrointestinal tract; by improving the preparation process, such as raw materials, reaction time and application of additives can further improve drug release, enhance insulin release in specific parts, and enduce new functions such as slow release and promotion of drugs penetration and absorption. Six literatures were selected from 10 experimental studies addressing other biological materials, for example liposomes, nanoparticles, hydrogels, microspheres, microcapsules as insulin carriers. Analysis indicated that these biological materials are non-toxic, non-immunogenic, biodegradable, biocompatible, have good in vitro release and hypoglycemic effects. CONCLUSION: Chitosan and other biological materials such as liposomes, nanoparticles, hydrogels, microspheres, microcapsules, as a carrier of insulin, are present with good drug release properties, which are feasible in clinical application. Related Articles | Metrics

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Occluder material characteristics and biocompatibility with the host Wu Shun-fen, Chen Gang 2010, 14 (29):  5463-5466.  doi: 10.3969/j.issn.1673-8225.2010.29.036 Abstract ( 128 )   PDF (717KB) ( 416 )   Save OBJECTIVE: To evaluate the properties of different occluder materials and their biocompatibility with the host, to provide reference for its clinical applications. METHODS: Using “occluder, blocking materials, histocompatibility, blood compatibility, congenital heart disease” in Chinese and “blocking material, occluder, histocompatibility, blood compatibility, congenital heart disease” in English as the key words, a computer search was performed for relevant articles between January 2006 and March 2010. Articles related to the biocompatibility of biomaterials with the host were included; repeated study or Meta analysis articles were excluded. Totally 30 articles mainly focuses on the type, properties and application prospect of occluder materials. RESULTS: There are many types of cardiac occluder, domestic Ampeatzer occluder has been widely used, the materials are mainly the nickel-titanium alloy, with good biocompatibility, good blocking effect and low cost, thus widely applying in clinics. CONCLUSION: Although metal occluder has been widely used, corrosion is inevitable, thus leading to poor compatibility and surrounding tissue inflammation, resulting in disease and hemolysis or clotting phenomena. Ideal occluder material, no matter the material itself or its degradation products, can produce no inflammation and toxicity, so the occluder with good biocompatibility need to be further developed. Related Articles | Metrics

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Material types and characteristics of artificial skin substitutes Zhao Guang-jian, Zhao Yao 2010, 14 (29):  5467-5470.  doi: 10.3969/j.issn.1673-8225.2010.29.037 Abstract ( 338 )   PDF (580KB) ( 1044 )   Save OBJECTIVE: To evaluate the properties and application of various biological materials for tissue engineered artificial skin substitutes, and to search an alternative to the human body. METHODS: Using “tissue engineering, artificial skin, scaffold” as the Chinese key words, “tissue engineering, artificial skin, intravascular stent” as the English key words, a computer search was performed for articles published between January 1993 and October 2009. Articles related with the biological materials and artificial skin repair were included; repeat study or Meta analysis articles were excluded. The involving 26 articles mainly discussed tissue engineered artificial skin substitutes and their performance. RESULTS: Tissue engineered artificial skin is to inoculate the epithelial cells and fibroblasts, which are in vitro cultured amplified using tissue engineering technology, into materials with good biocompatibility, and to form skin substitutes of similar epidermis and dermis structures with normal skin following in vitro culture. Then skin substitutes are transplanted into the skin wound to achieve wound repair and reconstruction. The currently research focus of tissue engineering biomaterials is how to compound two or more materials, or various kinds of modifications on the surface of biological materials, how to promote adhesion between cells and materials, how to enhance the biological activity of cells, and how to maintain biological functions. CONCLUSION: There is no one kind of artificial materials that fully comply with the requirements of tissue engineering. Further research should focus on the improvement of the micro-scaffold permeability and biological activity, and promoting the capillary growth; preparing biomaterial scaffold of bionic structure and highly active compound scaffolds. Related Articles | Metrics

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Research and progress of scaffold materials for tissue engineered heart valves Zou Ming-hui, Dong Nian-guo 2010, 14 (29):  5471-8474.  doi: 10.3969/j.issn.1673-8225.2010.29.038 Abstract ( 85 )   PDF (603KB) ( 431 )   Save BACKGROUND: Tissue engineered heart valves might bear promising surgical solutions of valvular heart disease for overcoming the limitations of biological and mechanical heart valve substitutes. Scaffolds play a central role in the tissue engineering. However, researchers often encounter an enormous variety of choices when selecting scaffolds for tissue engineered heart valves. OBJECTIVE: To highlight the role of extracellular matrix and its interactions with cells in tissue dynamics, and to review the major scaffolding materials which are used widely by describing their merits and disadvantages. METHODS: An online search of Pubmed database was performed using key words of “heart valves, tissue engineering” in Mesh for articles published between January 2000 and August 2009. A total of 186 literatures were screened out, including 34 reviews and 152 experimental studies. Among them, 39 articles which were related to scaffolding materials of tissue engineered heart valve, published in authorized journal and considered to be a representative, were selected. RESULTS AND CONCLUSION: Natural scaffolds have inimitable biomimicry because of their good biocompatibility and three-dimensional microstructure compared to other materials. Synthetic degradable polymer materials have attracted the attention of researchers due to their well controllability, absorbability and biomechanical properties. The composite scaffold materials of synthetic polymer and natural materials are a potential alternative and has a promising application prospect. Related Articles | Metrics

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Thermal and mechanical properties of biodegradable stent materials and their biocompatibility with the host Chen Bao-ai, Luo Qi-yi 2010, 14 (29):  5475-5478.  doi: 10.3969/j.issn.1673-8225.2010.29.039 Abstract ( 79 )   PDF (604KB) ( 594 )   Save BACKGROUND: Nowadays the metal stent, which is clinically widely used, may weaken the MRI or CT image of the coronary artery as a foreigner in the body. Besides, the metal stent may disturb revascularization, block collateral circulation forming and inhibit vascular remodeling. As a result, it needs antiplatelet therapy for a long time. So, a new biodegradable material to prepare a temporary, degradable coronary stent becomes a hot research. OBJECTIVE: To introduces in details the thermal properties, mechanical properties, degradation properties and biocompatibility of polymers used in biodegradable stent research. Based on the biodegradable stent’s requirements for the materials, different candidate materials were compared and an elementary selection for proper materials was made. Then the research progress on biodegradable stent materials was reviewed. This paper would work as a guide in the selection of proper material for the biodegradable stent. METHODS: Using “biodegradable stent, biodegradable material, PLA, PGA, PCL, PLGA” as the key words, Science Direct journal database from 2000 to 2010 was retrieved. Using “biodegradable stent, biodegradable material, PLA, PGA, PCL, PLGA” in Chinese as the key words, Wanfang database from 2002 to 2010 was retrieved. Literatures were limited to English and Chinese. The document retrieval is focused on the properties study of the biodegradable polymer materials and application on biodegradable coronary stent. Every included document is required to have strong point to the criteria. RESULTS AND CONCLUSION: The initially chosen raw materials for biodegradable coronary stent are PLA, PGA, PCL. Study shows that by blending or co-polymerization of those two or three, appropriate thermal, mechanical properties and degradation speed could be obtained, and numerous studies have conducted in documents and clinical application. Compared to the permanent metal stent, the degradable stent exhibits irreplaceable advantages, which determines its wide application prospect. Related Articles | Metrics

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Application of transparent conductive film carrier materials in label-free electrochemical biochip Wu Hui-jun, Luo Li-lin, Zhang Yu-qin 2010, 14 (29):  5479-5482.  doi: 10.3969/j.issn.1673-8225.2010.29.040 Abstract ( 101 )   PDF (567KB) ( 446 )   Save BACKGROUND: Based on DNA hybridization, the label-free electrical detection technology offers an important way to obtain a high sensitivity, strong specificity, high reliability, micro-portable and low-cost electrochemical DNA biochip. A carrier material with excellent physico-chemical characteristics plays a crucial role on highly efficient and stable transfer of the bioelectrical signals in the DNA biochip systems. OBJECTIVE: To investigate and summarize the research progress in carrier materials of label-free electrochemical DNA biochip using transparent conductive oxide films, and to prospect its development trends. METHODS: A computer-based online search of Elsevier and APS full-text databases was performed for articles and reviews published between 2001 and 2010 using the key words of “Electrochemical DNA biochip/biosensor; Label-free electrical detection; Carrier materials; Transparent conductive oxide films”. Researches about carrier materials of the label-free electrochemical DNA biochip using transparent conductive oxide films were included. Irrelevant or repetitive articles were excluded. RESULTS AND CONCLUSION: Transparent conductive oxide films can be used as new carrier materials of the label-free electrochemical DNA biochip by functionalized modification. Compared with other types of the film carrier materials, it was one of the ideal carrier materials of the label-free electrochemical DNA biochip due to superior electrical properties, chemical stability, good biocompatibility, and simple preparation process. However, it was still in preliminary research, so future study should focus on the effects of physico-chemical characteristics of the transparent conductive oxide film carrier materials on detection sensitivity, specificity, reliability of the bioelectrical signals. As a result, the electron transfer mechanism of the bioelectrical signals on the carrier materials and their interface with biomolecules can be obtained. Related Articles | Metrics

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Application and progress of microencapsulation technology in medical field Yang Xiao-yun, Chen Er-tong, Zhou Yan1, Liu Bao-lin, Zhang Hua, Xu Wen-qiang, Li Qiao-qiao,Ye Ping, Peng Cheng-hong,Han Bao-san 2010, 14 (29):  5483-5488.  doi: 10.3969/j.issn.1673-8225.2010.29.041 Abstract ( 89 )   PDF (660KB) ( 382 )   Save BACKGROUND: The study of microcapsule attracts great attention from the medical field due to its characteristics of immunoisolation, immunoprotection, as well as the controlled release. The microcapsule has been widely used in the therapy of diabetes, Parkinson disease, hepatic failure, analgesic effect, tumor, etc. OBJECTIVE: To summarize the characteristics of microencapsulated technology and its application in the medicine field. METHODS: Information from PubMed (http://www.ncbi.nlm.nih.gov/PubMed) and Wanfang databases (http://www.wanfangdata.com.cn) were retrieved by the first author using key words of “microencapsulated, transplantation, controlled release” both in English and Chinese. RESULTS AND CONCLUSION: As a kind of carrier, microcapsule supplies a three-dimensional matrix for cell culture, which could improve the intercellular effect and the function of cells; it forms an immune barrier for allogeneic cells, which prevent immunocyte from recognizing while do not affect the transportation of nutrients, oxygen and metabolites. It can treat diseases by providing the long-term stable controlled and released effective components for bodies. Although a lot of studies have reported the application of the microencapsulated technology in diabetes, Parkinson disease, hepatic failure, spinal cord injury, hypothyroidism, orthopaedics, tumor cancer and so on, clinical application remains still difficult. While expanding the application of microencapsulated technology in medical field, the ideal structure, good biocompatibility and controlled semi-permeable membrane of the microcapsule should be strengthened. Related Articles | Metrics

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Influential factors for color stability of maxillofacial silicone elastomer prosthesis Sun Hong-mei, Jia An-qi 2010, 14 (29):  5489-5492.  doi: 10.3969/j.issn.1673-8225.2010.29.042 Abstract ( 139 )   PDF (583KB) ( 428 )   Save BACKGROUND: Currently, silicone elastomer has been widely used as an ideal material of repairing maxillofacial defects. However, instable color of elastomer prosthesis is the key factor of influencing the serve life. OBJECTIVE: To summarize the influencing factors on the color stability of silicone elastomer prosthesis, and to provide evidence for clinical instruction. METHODS: Using “silicone elastomer, prosthesis” in Chinese and in English, a computer search was performed among VIP Periodical Full-text Database and PubMed database from September 1987 to December 2009 to retrieve articles on chromatology instability. Literatures about silicone tube colors were included. Literatures of irrelevant purpose and repetitive content were excluded. Thirty-eight literatures were involved in analysis. RESULTS AND CONCLUSION: The influencing factors of the color stability of maxillofacial elastomer were summarized. The optical qualities, coloration, and the aging of materials are closely relative to the color stability of silicone elastomer prosthesis. Therefore, how to prevent the elastomer from fading and to prolong the serve life of the prosthesis is a prospective topic of current studies. However, the mechanism of the color instability of the prosthesis needs to be further explored on the molecule level. Related Articles | Metrics

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Development and application of tissue engineered scaffold materials in urinary system Wang Ji-hong, Xu Yue-min 2010, 14 (29):  5493-5497.  doi: 10.3969/j.issn.1673-8225.2010.29.043 Abstract ( 111 )   PDF (558KB) ( 552 )   Save BACKGROUND: There is an increasing number of reports addressing the reconstruction of various urinary organs, such as the bladder, urethra, ureter and corpus cavernosum penis, by using tissue engineering approaches, and scaffold materials have great significance in the reconstruction. OBJECTIVE: To summarize the current development of scaffold materials in tissue engineering repair and reconstruction for urinary organs based on the recent literatures. METHODS: An online search was conducted in Pubmed database and CNKI database to identify the articles related to scaffolds biomaterials in urology published from January 2003 to November 2009 using the key words of “tissue engineering, biomaterials, urethra, bladder, urology” in English and “tissue engineering, scaffolds, urethra, bladder, urinary tract” in Chinese. Inclusive criterion: The contents of articles were related to the application of tissue engineered scaffolds in urology, those published recently or in authorized journals are preferred as for the same field. RESULTS AND CONCLUSION: Using biological materials as tissue engineering scaffold for organ repair and reconstruction is currently the main areas of urinary system tissue engineering research, a variety of natural, artificial and composite materials have used in animal experiments or clinical applications, in particular the recent development and application of nanotechnology has opened up a new way for tissue engineering, therefore, it is a promising direction of urinary system tissue engineering scaffold materials that selecting alternative materials of similar physico-chemical property and ultrastructure. Related Articles | Metrics

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Interaction between silver ions and histidine You Yu-hua, Zhang Chao-ping 2010, 14 (29):  5498-5504.  doi: 10.3969/j.issn.1673-8225.2010.29.044 Abstract ( 196 )   PDF (392KB) ( 678 )   Save BACKGROUND: Traditionally, UV/visible spectra, conductivity, electrophoresis and other methods are commonly applied for studying the interaction of metal ions and amino acids, but UV-Vis spectroscopy and fluorescence spectroscopy for L-histidine reacted with silver ion in aqueous solution is rarely reported. OBJECTIVE: To investigate the interaction between silver ion and histidine using UV/VIS and fluorescence spectra. METHODS: The influence of pH, multicomponent concentration such as histidine, silver ion, formaldehyde, sodium dodecyl sulfate and trihydroxymethyl aminomethane, as well as illumination strength and time, on the interaction between silver ion and histidine were investigated, and the mechanism of reaction was also explored. RESULTS AND CONCLUSION: Applied pH potentiometer titration method, the dissociation constants of histidine was defined 9.21. The stepwise stability constants of histidine-silver was ㏒K1=5.56 and ㏒K2=4.05, respectively by using half n(_) method. At    20 ℃, the electric potential of histidine-silver system was 2.10×10-4 V. According to pH potentiometer titration and Iob method, the compound was consisted of histidine: Ag = 2:1. Compared with histidine, histidine-silver systems reached a shoulder peak at 295.3 nm, which was assigned to conjugate double bond of imidazole ring that easily generated π-π* transition. And an absorption peak close to 242 nm can be assigned to n-π* transition of the C＝O group of the histidine-silver. The fluorescence emission spectra of histidine-silver systems belonged to 5D0→7F2 electric dipole transition. Compared with reference solutions under the same conditions, it not only emitted wavelengths blue shift, but also induced fluorescence quenching. Results showed that, imidazole ring was involved in the bonding action with silver ion. The reaction process is to firstly generate six-coordination complex, secondly reduce the silver ion into ultrafine silver particles which are bound by histidine. Related Articles | Metrics

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N-dimethylacrylamide)-b-poly(?-caprolactone) micelles for paclitaxel thermo-sensitive controlled release behaviors Cai Qing, Zhang Lei, Yang Jing, Jin Ri-guang 2010, 14 (29):  5505-5510.  doi: 10.3969/j.issn.1673-8225.2010.29.045 Abstract ( 164 )   PDF (425KB) ( 554 )   Save BACKGROUND: Polymer micelles is a new type of drug carriers developed in recent years, with a wide range of carrying drugs, structural stability, excellent tissue permeability, long residence of drugs in vivo, and effective reaching the target. The performances of intelligent targeting and decreasing the initial burst release have become the focus of recent researches. OBJECTIVE: To obtain an intelligent targeting drug carrier of low critical solution temperature (LCST) at 40 ℃, to change drug release behavior through the changes of temperature, and to further improve the stability and drug release behavior of the micelles by core-crosslinking.  METHODS: By radical polymerization of N-isopropylacrylamide (NIPAAm) and N, N-dimethylacrylamide (DMAAm), hydroxyl terminated poly(N-isopropylacrylamide-co-N, N-dimethyl acrylamide) [P(NIPAAm-co-DMAAm)] was synthesized. Molecular weight and LCST of P(NIPAAm-co-DMAAm) were regulated by adjusting the mercaptoethanol and monomer ratio, as well as the ratio of NIPAAm and DMAAm. Amphiphilic block copolymer P(NIPAAm-co-DMAAm)-b-PCL was prepared via bulk ring-opening polymerization of ε-caprolactone by using the end hydroxyl group of P(NIPAAm-co-DMAAm) as initiator and stannous octoate as catalyst. The block copolymer reacted with acryloyl chloride to obtain amphiphilic block copolymers with unsaturated double bonds at the terminal. Drug loaded nano-micelles with different nuclear cross-linked degrees were prepared by dialysis method, and its release behavior was investigated. RESULTS AND CONCLUSION: Amphiphilic block copolymers, with the LCST of 42 ℃, were obtained with hydroxyl or acryloyl endgroup. By blending them at different ratios, thermo-sensitive drug-loaded nano-micelles with different core-crosslinking degrees were prepared. The drug release rate was faster at 43 ℃ than at 37 ℃. With the core-crosslinking degrees increasing, the release of paclitaxel gradually slowed. The results suggest that the drug release rate from micelles prepared from thermo-sensitive P(NIPAAm-co-DMAAm)-b-PCL can be regulated by the degree of cross-linking. Related Articles | Metrics