Objective To evaluate the feasibility of the porous titanium/chitosan/hydroxyapatite (Ti/Ch/HA) composite scaffold as a bone repair substitute.Methods Additive manufacturing (3D printing) technology was used to fabricate porous Ti scaffolds as supporting structures.Chitosan/hydroxyapatite (Ch/HA) sponge was prepared within the macro-pores of Ti scaffolds using freeze drying technology.Thus,a kind of composite porous Ti/Ch/HA scaffold with good cell affinity was obtained.Osteoblastic cells were seeded and cultured in pure porous Ti scaffolds and composite Ti/Ch/HA scaffolds for 7 days.The cellular morphology,seeding efficiency and proliferation were examined and compared between the 2 kinds of scaffolds using scanning electron microscopy (SEM) and MTT assay.Results The SEM examination showed that the macro-pores of Ti/Ch/HA scaffolds were full of the composite sponge structure of Ch/HA,with a micropore size of 50 to 200 μm.Like the pure porous Ti scaffolds,composite Ti/Ch/HA ones have a compressive strength of 168.2 to 192.6 MPa,a yielding strength of 137.1 to 154.1 MPa,and a Young's modulus of 3.21 to 4.51 GPa.After culture for 7 days,a large number of flat cells adhered onto the surface of Ti scaffolds while the cells adhering onto the Ti/Ch/HA composite scaffolds were fusiform.The seeding efficiency of osteoblastic cells in the composite Ti/Ch/HA scaffolds (73.218％ ± 3.748％) was significantly higher than that in the pure porous Ti scaffolds (21.352％ ±4.365％) (P ＜0.05);the OD value of the composite Ti/Ch/HA scaffolds (0.783 ±0.043) was significantly higher than that of the pure porous Ti scaffolds (0.382 ± 0.036) (P ＜ 0.05).Conclusions Ti/Ch/HA composite scaffolds can match human bone in mechanical properties.Compared with pure porous Ti scaffolds,the Ti/Ch/HA composite ones are more suitable for adhesion and proliferation of osteoblasts,making them an ideal kind of bone repair substitute.

ObjectiveTo evaluate the association between Pro12Ala polymorphism in peroxisome proliferator activated receptorγ2 (PPARγ2) gene and gestational diabetes mellitus(GDM).Methods Publications on genetic association studies of PPARγ2 and GDM were searched using the PubMed database, The HuGE Navigator, China National Knowledge Infrastructure (CNKI), Wanfang database and VIP Science from the inception of the databases to December 1, 2014. Two reviewers independently selected literature according to the inclusion and exclusion criteria, extracted data and assessed the quality of the data using the Newcastle-Ottawa Scale (NOS) standard. Meta-analysis was performed using RevMan 5.3 software.ResultsOverall, 13 eligible articles were identified, including seven in English and six in Chinese, with a total of 2 787 GDM cases and 5 408 healthy controls. Quality assessment showed that the quality of the 13 articles was all good, with NOS≥5. (1) Pro12Ala polymorphism in PPARγ2 (allele Ala or genotype Ala/Ala or Pro/Ala) was shown to be highly associated with GDM occurrence on general evaluation, with anOR(95%CI) of 0.74(0.60-0.93) in the allele model and 0.79(0.65-0.96) in the dominant genetic model (P<0.05, respectively). (2) Pro12Ala polymorphism in PPARγ2 was shown to be highly associated with GDM occurrence in Asians in a stratification analysis of ethnicity in the populations included in the studies, with anOR(95%CI) of 0.61(0.48-0.79) in the allele model and 0.64(0.50-0.82) in the dominant genetic model (P<0.01, respectively). No correlation was found between the Pro12Ala polymorphism in PPARγ2 and GDM in the Caucasian population. (3) A meta-analysis of six Chinese studies showed that the Pro12Ala polymorphism in PPARγ2 was associated with the risk of GDM in the Chinese population, with anOR(95%CI) of 0.52 (0.36-0.73) in the allele model and 0.55(0.39-0.80) in the dominant genetic model (P<0.01, respectively). (4) No significant association was observed in the TaqMan allelic discrimination assay with anOR(95%CI) of 0.96(0.83-1.10) in the allele model and 0.95(0.81-1.11) in the dominant genetic model (P>0.05, respectively), although there was still a significant correlation in polymerase chain reaction-restriction fragment length polymorphism with anOR(95%CI) of 0.58(0.43-0.79) in the allele model and 0.62(0.45-0.85) in the dominant genetic model (P<0.01, respectively).ConclusionsThe Ala allele and the Ala/Ala or Pro/Ala genotypes of the Pro12Ala polymorphism in PPARγ2 can decrease the risk of GDM. However, there are differences in the results which are affected by the genotype analysis method or races.