Mechanical strength and inhibition of plaque biofilm activity of a novel antibacterial Hawley retainer / 口腔疾病防治

Objectives @#The purposes of this study were to evaluate the long-term mechanical property, bacteria-killing ability, protein resistance and cytotoxicity of a novel antibacterial methyl methacrylate (MMA) resin. @*Methods @#The 2-methacryloyloxyethyl phosphorylcholine (MPC) has been added into the MMA used for making Hawley orthodontic retener according to the mass percentage 0% (control group), 1.5%, 2.25%, 3%, 4.5% and 6%. Specimens from the control group and MPC group were water-aged for 1 d, 90 d and 180 d, and then the universal material testing machine was used to investigate the long-term mechanical properties of the modified MMA specimens in the oral environment. The biofilm metabolic activity, colony-forming unit (CFU) and live/dead staining assay of the biofilms in the control group and MPC group in the oral environment were tested using the dental plaque biofilm model. The micro-bicinchoninic acid (BCA) method was used to determine the amount of protein adsorbed on the specimens. The MTT method was used to evaluate the cytotoxicity of the control group and MPC group.@*Results @#In the simulated oral environment, the addition of 0% to 3% MPC had no significant effect on the mechanical properties of the MMA specimen (P > 0.05). The control group and the modified MMA specimens with 3%MPC were statistically significant in time and the interaction effects between the two groups (P < 0.05). With increasing intervention time, the mechanical strength of both groups decreased, and the effect of time varied with grouping. The protein adsorption on the surface of the modified MMA material after adding 3% MPC decreased by approximately 80%, the metabolic activity of the biofilm decreased by approximately 50%, and biofilm CFU counts decreased by approximately 70% (P < 0.05) compared with the control. There was no statistically significant difference in time or interaction effects between the two groups. The amount of live green bacteria in the 3% MPC group decreased significantly after 1, 90, and 180 d of water aging. There was no significant difference in cytotoxicity between the control group and the MPC group (P > 0.05). @*Conclusions @#The addition of MPC into the MMA resin did not compromise the mechanical properties of the resin and exhibited long-lasting antibacterial and protein-repellent effects.

Phosphorylcholine Oligomer-Grafted Graphene Oxide for the Transcatheter Arterial Chemoembolization of Liver Cancer / 中山大学学报(医学科学版)

[Objective]To investigate the safety and efficacy of phosphorylcholine oligomer grafted graphene oxide as a drug carrier for transcatheter arterial chemoembolization in the treatment of liver cancer.[Methods]Doxorubicin loaded folic acid labeled phosphorylcholine oligomer grafted graphene oxide(DOX@GO-PCn-FA)was prepared. Graphene ox-ide(GO)and DOX@GO-PCn-FA were injected intravenously via marginal ear vein in New Zealand white rabbits respec-tively to assess their safety and biodistribution for intravenous administration.Ten male New Zealand rabbits were used to establishe the VX2 liver cancer model and the tumor characteristics were confirmed by dynamic contrast enhanced CT scan.Catheter was inserted via femoral artery and advanced into hepatic lobar or segmental artery.Digital subtraction angi-ography(DSA)was performed to validate the tumor feeding vessels.DOX@GO-PCn-FA was injected through the cathe-ter to carry out selective transcatheter arterial chemoembolization(TACE). Dynamic enhanced CT scan and pathological examinations of major tissues and organs were implemented 7 days post TACE to evaluate the efficacy of embolization effect of DOX@GO-PCn-FA against liver tumor as well as the biodistribution and safety.[Results]Intravenous injection of GO resulted in significant thrombosis and pulmonary embolism whereas DOX@GO-PCn-FA of same dosage did not. DOX@GO-PCn-FA was capable of effectively diminishing the blood supply of liver tumors when applied in TACE. Pathologic exploration revealed that DOX@ GO-PCn-FA mainly deposited in the tumor,and no obvious complications were observed.[Conclusions]GO-PCn presented superior biocompatibility and exerted effective chemoembolization against liver cancer.

Phosphorylcholine coating enhances biocompatibility of expanded polytetrafluoroethylene used in polymeric prosthetic heart valves / 中国组织工程研究

BACKGROUND:Our preliminary study found that the monocusp valves made of ultramicropore expanded polytetrafluoroethylene (ePTFE) revealed no significant thrombus, calcification, or degradation 20 weeks after implanted into the descending aorta and the left pulmonary artery in sheep, which verified the good property of ePTFE. However, the surface of ePTFE in the left pulmonary artery was covered with obvious neointima. OBJECTIVE: To assess the biocompatibility of phosphorylcholine-coated ePTFE. METHODS:ePTFE surface was modified by phosphorylcholine derivative. Then the changes of surface shape, tensile stress at yield and elasticity modulus, water contact angle, and protein absorption capacity of ePTFE after surface modification were observed. (1) Hemolytic test: the leaching solution of phosphorylcholine-coated ePTFE, leaching solution of uncoated ePTFE, normal saline, and distiled water were added to the diluted human blood, respectively. (2) Platelet count test: the phosphorylcholine-coated ePTFE, uncoated ePTFE, high density polyethylene, and Zymosan A were added to the whole blood samples from healthy volunteers, respectively. (3) Platelet activation test: the phosphorylcholine-coated ePTFE, uncoated ePTFE, γ-Globulins, and Zymosan A were added to the whole blood samples from healthy volunteers, respectively. RESULTS AND CONCLUSION: The mean micropore diameter of ePTFE was significantly decreased after phosphorylcholine coating (P significantly strengthened after phosphorylcholine coating (P ePTFE in biomechanical properties and hemolytic test. The platelet count test and platelet activation test demonstrated that phosphorylcholine coating significantly improved anti-thrombus function of ePTFE. So, phosphorylcholine coating can enhance anti-thrombus function, suppress protein adsorption, and improve biocompatibility of ePTFE.

Simvastatin inhibits sphingosylphosphorylcholine-induced differentiation of human mesenchymal stem cells into smooth muscle cells

Sphingosylphosphorylcholine (SPC) induces differentiation of human adipose tissue-derived mesenchymal stem cells (hASCs) into smooth muscle-like cells expressing alpha-smooth muscle actin (alpha-SMA) via transforming growth factor-beta1/Smad2- and RhoA/Rho kinase-dependent mechanisms. 3-Hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (statins) have been known to have beneficial effects in the treatment of cardiovascular diseases. In the present study, we examined the effects of simvastatin on the SPC-induced alpha-SMA expression and Smad2 phosphorylation in hASCs. Simvastatin inhibited the SPC-induced alpha-SMA expression and sustained phosphorylation of Smad2 in hASCs. SPC treatment caused RhoA activation via a simvastatin-sensitive mechanism. The SPC-induced alpha-SMA expression and Smad2 phosphorylation were abrogated by pretreatment of the cells with the Rho kinase inhibitor Y27632 or overexpression of a dominant negative RhoA mutant. Furthermore, SPC induced secretion of TGF-beta1 and pretreatment with either Y27632 or simvastatin inhibited the SPC-induced TGF-beta1 secretion. These results suggest that simvastatin inhibits SPC-induced differentiation of hASCs into smooth muscle cells by attenuating the RhoA/Rho kinase-dependent activation of autocrine TGF-beta1/Smad2 signaling pathway.

Biocompatibility of phosphorylcholine modified alginate-chitosan microcapsules / 中华内分泌外科杂志

ObjectiveTo explore whether the biocompatibility of phosphorylcholine (PC) modified alginate-chitosan microcapsules could be improved. MethodsPC modified alginate-chitosan microcapsules were obtained by high-voltage electrostatic system.Bradford method was adopted to determine the adsorption amounts of bovine serum albumin by chitosan alone and PC modified chitosan.Alginate-chitosan-PC microcapsules (experimental group) and alginate-chitosan microcapsules ( control group) were respectively implanted into the peritoneal cavity of mice and retrieved 4 weeks after transplantation.Fibrosis of the capsules was evaluated by HE staining.Glucose stimulated insulin secretion (GSIS) assay was used to assess the insulin secretion response of encapsulated and nonencapsulated rat islets. Results The adsorption amount of protein was 189.4 μg/mg and 90.5 μg/mg respectively by chitosan alone and PC modified chitosan.The difference had statistical significance ( t =5.549, P ＜ 0.05 ).In contrast to the control group, the cellular reaction on the surface of the modified microcapsules was weaker, with no obvious fibrosis found.The insulin secreted by encapsulated islets and nonencapsulated islets was( 3.298 ± 1.680 ) μIU/ml VS (4.299 ± 1.159 ) μIU/ml ( t =1.096, P ＞ 0.05 ) in response to low-glucose stimulus and( 11.783 ± 4.175 ) μIU/ml VS ( 12.875 ± 2.268 ) μIU/ml ( t =0.514, P ＞ 0.05 ) in response to high-glucose stimulus.Conclusions PC can improve the biocompatibility of alginate-chitosan microcapsules, with no effect on the biological function of encapsulated islets.It may be more appropriate to use modified microcapsules encapsulating islets for transplantation.

Clinical evaluation of the dexamethasone coated stent in coronary small vessel disease / 中国介入心脏病学杂志

ObjectiveTo evaluate the clinical results of intracoronary implantation of the phosphorylcholine dexamethasone coated biodivysio small coronary stents. Methods Prospective analyses of long-term results of the phosphorylcholine dexamethasone coated biodivysio coronary stents, and their implantation performed on 82 coronary artery disease patients were conducted. We implanted 106 stents of which 54 were the phosphorylcholine dexamethasone coated biodivysio coronary stents, and 52 the phosphorylcholine coated biodivysio coronary stents. Results The success rate of the implantation of both groups was 100%. The major adverse cardiac events (MACE) of the 3-month follow-up in the phosphorylcholine dexamethasone coated biodivysio coronary stents group were 9.8%; and in the phosphorylcholine coated biodivysio coronary stents group were 22.0%. The restenosis rate of the 8-month follow-up in the phosphorylcholine dexamethasone coated biodivysio coronary stents group was 4.9%; and in the phosphorylcholine coated biodivysio coronary stents group was 23.0%. Conclusion The implantation of the phosphorylcholine dexamethasone coated biodivysio coronary stents is a safe and efficient interventional procedure with a high success rate and few MACE. It may reduce restenosis rate.