BACKGROUND:Polylactic acid(PLA)surface is hydrophobic and there are no nataral recognition sites,so its application is limited.Many different strategies have been studied such as composition and chemical Drafting,to produce hydrophilic groups.However,these traditional methods are always involved in complex process and many organic reagents,resulting in decrease of biocompatibility.OBJECTIVE:To conduct the surfacr modification of PL.A and improve its hydrophilicity with low temperature plasma treatment.DESIGN:Controlled observation.SETTING:Department of Materials Science and Engineering in Jinan University.MATERIAIS:The experiment was processed from October 2004 to October 2005 at Guangzhou Research Center of Artificial Organs and Materials Engineering(Ministry of Education).The mainly used materials were:Poly-D,L-lactic acid(Mr 2.9×104,Shandong Medical Instrument Institute),N-vinyl-pyrrolidone(NVP,Acros Company,purified before use).METHODS:The materials were treated in the plasma reactor under different conditions(power=150 W,t=3,2,1 minutes;power=30 W,t=10,8,5,3,1 minutes)to choose the optimal condition,and then PLA were grafted with NVP by gas phase polymerization and liquid polymerization,respectively.MAIN OUTCOME MEASURES:THe surface morphology of the films was observed with scanning electron microscopy and atomic force microscopy.The hydrophilicity of native and treated material surfaces was measured using a water contact angle meter.Surface composition was detected with Fourier transform infrared spectrometer.Mass changesmeasurement was applied to characterize the grafting efficiency.RESULTS:Scanning electron microscopy and atomic force microscopy showed that the plasma medified materials possessed coarse surface with pores and notches.Water contact angles decreased obviously from 78°to 50°after grafting,Fourier transform infrared spectrometer showed a new absorption peak at 1 637.19 cm-1,which corresponded to the carbonyl stretch vibration absorption of amide group in poly-N-vinyl-pyrrolidone.After the plasma treatmerlt at low temperature.the mass change ratio of PLA film material was-0.6.CONCLUSION:The plasma treatment and polymerization can improve the hydrophilicity and cause coarsr surface of PLA material,which will be helpful for the cell attachment.

BACKGROUND: Studies have shown that chitooligosaccharides have antitumor effect. However, the influence of chitooligosaccharides on cyclin D1, bcl-2 and bcl-xl remains unclear.OBJECTIVE: To observe the JnhJbJtJon effect of chitooligosaccharides on the proliferation of Hela cells, and the influence on cyclin D1, bcl-xl and bcl-2 mRNA expression.METHODS: Hela cells were stimulated by different concentrations of chitooligosaccharides (0.1, 0.5, 1, 2, 5 g/L). The effects of chitooligosaccharides on Hela cells were detected by CCK8 kit. Using real-time PCR methods, the gene expression of cyclin D1, bcl-xl and bcl-2 mRNA were determined.RESULTS AND CONCLUSION: Chitooligosaccharides inhibited the proliferation of Hela cells. With the concentrations of chitoolJgosaccharides increased from 0.1 g/L to 2 g/L, the inhibition effects on the gene expressJon of cyclin D1, bcl-xl and bcl-2 were enhanced, peaked at 2 g/L, and decreased at high concentration (5 g/L). Antitumor activity of chitooligosaccharides may exert through two aspects: it inhibits cyclin D1 mRNA expression to suppress the proliferation of tumor cells; on the other hand, chitooligosaccharides inhibits the expression of bcl-xl and bci-2 to promote the apoptosis of tumor cells. Moreover, the effects of the former are stronger than the latter.

Compound membranes of chitosan/hydroxyapatite were prepared by blending. The physical performance showed that the air-water contact angles decreased from chitosan's 103 degrees to chitosan/hydroxyapatite's 57 and the water adsorption rate increased slightly. When immersed into culture medium, the materials adsorbed Ca2+, and low crystalline hydroxyapatite deposited on the surface of the membranes. Chitosan/hydroxyapatite compound membranes could enhance the attachment and proliferation of mescenchymal stem cells (MSCs). After 12 days' induction on the materials, the alkaline phosphatase (ALP) activity value of MSCs on the compound membrane was 10.1, being much higher than 1.6 on chitosan membrane (P<0.01). All these results indicate that chitosan does not have very good affinity for MSCs, but the biocompatibility of chitosan can be apparently enhanced after mixing with hydroxyapatite. The compound membrane stimulates MSCs to differentiate into osteoblasts and it may be a good potential material for bone substitution.
Alkaline Phosphatase ; metabolism ; Animals ; Bone Substitutes ; pharmacology ; Cell Proliferation ; drug effects ; Cells, Cultured ; Chitosan ; chemical synthesis ; pharmacology ; Durapatite ; chemical synthesis ; pharmacology ; Membranes, Artificial ; Mesenchymal Stromal Cells ; cytology ; Rats

BACKGROUND: With the increasing number of patients undergoing knee arthroplasty in China, the complications caused by the mismatch of prosthesis with anatomical parameters arouse extensive attentions.OBJECTIVE: To measure the anatomical parameters of the knee joints in healthy Zhuang ethnic group from Guangxi Zhuang Autonomous Region, China, using three-dimensional (3D) reconstruction technology, thus providing reference for the design and placement of the hip prosthesis.METHODS: Sixty-eight individuals, including 30 females and 38 males, were selected from 217 healthy people undergoing CT examination. All data were imported into Mimics 15.0 software used for 3D reconstruction, and then the knee parameters were then measured and analyzed.RESULTS AND CONCLUSION: There was no significant difference in the parameters of the bilateral femur and tibia (P > 0.05). The femoral parameters had significant differences between genders (P < 0.05). The width of tibial platform, sagittal length of lateral tibial platform, distance between medial tibial plateau and fibular head, and posterior slope of tibial plateau showed no significant differences between genders (P > 0.05), while there were significant differences in the width of medial/lateral tibial platform, and sagittal length of medial tibial platform between genders (P < 0.05). The sagittal length of medial femoral condyle was negatively correlated with age, and all femoral parameters were positively correlated with height; while only the width of medial and lateral tibial platform were positively correlated with height. To conclude, 3D reconstruction technology is available for research on the morphology of the knee joint in the Zhuang ethnic group from Guangxi Zhuang Autonomous Region, which provides references for prosthesis design and research appropriate for the Zhuang ethnic group.

BACKGROUND:Previous studies have confirmed that ethanol can promote adipogenic differentiation of bone marrow mesenchymal stem cells (BMSCs), and up-regulate the expression of PPARγ and aP2 in the tumor necrosis factor α (TNF-α) signaling pathway. As a member of the ZIP protein family, Zrt/Irt-like protein 1 (ZIP1) is closely related to bone metabolism and osteogenic differentiation.OBJECTIVE:To study the effect of BMSCs transfected by ZIP1 on TNF-α signaling pathway in the process of adipogenic differentiation.METHODS:The BMSCs from rabbits were isolated and cultured under different concentrations of alcohol (0.03, 0.09,0.15, 0.21 mol/L), followed by transfection by ZIP1 siRNA and ZIP1 expression vector.RESULTS AND CONCLUSION:After culture in alcohol, the expression levels of aP2 and PPARγ proteins were both significantly increased (P < 0.05), and the level of triglyceride was increased in all alcohol groups except for 0.03 mol/L alcohol group (P < 0.05). After siRNA transfection, the expression levels of aP2 and PPARγ as well as the level of triglyceride were increased significantly in all the alcohol groups (P < 0.05); however, ZIP1 transfection decreased the expression levels of aP2 and PPARγ proteins (P < 0.05). To conclude, ZIP1 siRNA could promote the adipogenic differentiation of BMSCs through the activation of TNF-α signaling pathway.