BACKGROUND: Three-dimensional (3D) printing technique has showed unparalleled advantages in the field of tissue engineering scaffold preparation because of its outstanding merits of convenience, efficiency, controllability and ability to construct complex shapes.OBJECTIVE: To fabricate Fe-containing mesoporous calcium-silicate (MCS) /poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) composite scaffolds using the 3D printing technique and to test the characterization and cellular biocompatibility of the composite scaffolds.METHODS: Four groups of Fe-containing MCS/PHBHHx composite scaffolds were fabricated using 3D printing technique. The molar percentage of Fe in these four groups was 0%, 5%, 10%, 15%, respectively and they were marked as 0Fe-MCS/PHBHHx, 5Fe-MCS/PHBHHx, 10Fe-MCS/PHBHHx and 15Fe-MCS/PHBHHx. The scanning electron microscopy was used to observe the microstructure of the scaffolds after being soaked in the simulated body fluid.Osteoblast cell lines MC3T3-E1 were seeded on these four groups of scaffolds as well. Cell counting kit-8 method was adopted to test the cell proliferation at 1, 3, 7 days of culture. Intracellular alkaline phosphatase activity was tested at 7 and 14 days of culture.RESULTS AND CONCLUSION: (1) Compared with the scaffolds with no soaking process, spherical particles were formed on the scaffolds because of mineralization after soaking 3 days in the simulated body fluid. (2) At 1 day of culture,there was no difference in cell proliferation among the four groups. At 3 days of culture, the proliferation rate of the 15Fe-MCS/PHBHHx scaffold was remarkably higher than that of the rest three groups (P < 0.05). At 7 days of culture,the proliferation rate was significantly higher in the 10Fe-MCS/PHBHH and 15Fe-MCS/PHBHHx scaffolds than the 0Fe-MCS/PHBHH scaffold (P < 0.05), as well as significantly higher in the 15Fe-MCS/PHBHHx scaffold than the 10Fe-MCS/PHBHH scaffold (P < 0.05). (3) At 7 days of culture, no difference in alkaline phosphatase activity could be found among these four groups of scaffolds; however, at 14 days, the 5Fe-MCS/PHBHHx, 10Fe-MCS/PHBHHx and 15Fe-MCS/PHBHHx scaffolds exhibited an enhanced alkaline phosphatase activity compared with the 0Fe-MCS/PHBHHx scaffold. Meanwhile, the 15Fe-MCS/PHBHHx showed the highest alkaline phosphatase activity.These findings indicate that the MCS/PHBHH scaffolds containing Fe could promote the proliferation and osteogenic differentiation of the MC3T3-E1 cells.

BACKGROUND:Macropore morphology of a composite scaffold prepared by the three-dimensional printing technique is of great importance in determining the physicochemical and biological properties of tissue engineering scaffolds.OBJECTIVE:To fabricate strontium-containing mesoporous (Sr-MBG) bioactive glass (PCL) scaffolds by the three-dimensional printing technique, and to explore the effect of these scaffolds on MC3T3-E1 proliferation and osteogenic differentiation, thereby to find out the optimal macropore morphology.METHODS: Sr-MBG/PCL composite scaffolds were fabricated by the three-dimensional printing technique. The angles between fibrous latitudes and longitudes were set to 45°, 60° and 90°. Then the proliferation and alkaline phosphatase activity of MC3T3-E1 cells on the scaffolds were tested.RESULTS AND CONCLUSION: Cell counting kit-8 results showed that MC3T3-E1 cells could proliferate on all the three kinds of scaffolds. The proliferation rate of MC3T3-E1 cells on the 45° Sr-MBG/PCL scaffolds was just slightly higher than that on the 60° and 90° Sr-MBG/PCL scaffolds at days 1 and 4 (P > 0.05), but there was a significant increase at day 7 (P < 0.05). The 45° Sr-MBG/PCL scaffolds exhibited a significant increase in alkaline phosphatase activity of MC3T3-E1 cells compared to the 60° and 90° Sr-MBG/PCL scaffolds at day 14 (P < 0.05), while there was no significant difference among three groups at day 21 (P > 0.05). These results indicate that the 45° Sr-MBG/PCL scaffold is more suitable to promote the proliferation and osteogenic differentiation of the MC3T3 cells than the 60° and 90° Sr-MBG/PCL scaffolds.

OBJECTIVETo analyze the clinical features and TGFBI gene mutation in a Chinese family affected with Reis-Bucklers corneal dystrophy.

METHODSGenomic DNA was extracted from 53 members including 9 patients from the family. The 17 exons and splice region of introns of the TGFBI gene were amplified by PCR and directly sequenced. All family members were subjected to ophthalmologic examination.

RESULTSA heterozygous mutation (R124L) was found in exon 4 of the TGFBI gene among all patients from the family. The same mutation was not found among unaffected family members. The inheritance pattern of the family was identified as autosomal dominant, and the Reis-Bucklers corneal dystrophy in the family was diagnosed as the geographic type.

CONCLUSIONThe R124L mutation of the TGFBI gene probably underlies the pathogenesis of Reis-Bucklers corneal dystrophy in this Chinese family. Molecular genetic approach is useful for the proper diagnosis of this type of corneal dystrophy.

Corneal Dystrophies, Hereditary ; etiology ; genetics ; Female ; Humans ; Male ; Mutation ; Sequence Analysis, DNA ; Transforming Growth Factor beta1 ; genetics

OBJECTIVETo explore the clinical features and mutation of TGFBI gene in a Chinese pedigree affected with lattice corneal dystrophy (LCD).

METHODSGenomic DNA was extracted from 35 members including 11 patients from the pedigree. The 17 exons and splicing region of introns of the TGFBI gene were amplified by PCR. The products were directly sequenced and compared with GenBank database to identify potential mutation. Bioinformatic analysis was carried out to predict the effect of mutation on proteins.

RESULTSA heterozygous mutation (p.R124C) was found in exon 4 of the TGFBI gene in all patients from the pedigree but not among unaffected members. The mode of inheritance of corneal dystrophy in this pedigree was identified as autosomal dominant. Bioinformatics analysis predicted that the p.R124C mutation may be functionally deleterious. The phenotype of corneal dystrophy in the pedigree was determined to be LCD I type.

CONCLUSIONThe p.R124C mutation of the TGFBI gene probably underlies the pathogenesis of LCD in this Chinese pedigree. Genetic testing can facilitate proper diagnosis of this type of corneal dystrophy.

Objective A finite element analysis was conducted on the biomechanics of the locking plate and intramedullary nail fixation for the treatment of distal tibial fractures,and the resuhs were verified combined with clinical cases,so as to provide references for clinical treatment.Methods (1) Finite element analysis:the three-dimensional CT data of the lower limbs of a healthy male volunteer were used to establish a finite element model.The internal stress distribution of the tibial plateau was set to 60％ of the total load by intramedullary nail and locking plate respectively,and the tibia end was fixed effectively.400 N axial pressure load which equaled to that of adult knee joint during single axis standing was simulated.The equivalent stress and displacement of the model by different fixations were compared.(2) Clinical verification:a retrospective case control study was performed on the clinical data of 37 cases of distal tibia1 fractures treated with internal fixation from June 2015 to December 2016,including 17 cases in intramedullary nail group and 20 in locking plate group.The operation time,intraoperative blood loss,postoperative fracture healing time,and postoperative Johner-Wruhs score of patients were recorded for comprehensive assessment of recovery.Results (1) The finite element analysis results:the maximum stress value was 5.907 MPa for intramedullary nail and 5.821 MPa for locking plate model (P ＞0.05),respectively.The maximum displacement of intramedullary nail model was 2.313 mm,lower than that of locking plate fixation system (3.854 rmm) (P ＜ 0.05).(2) Clinical verification:the operation time and intraoperative blood loss of intramedullary nail were both lower than those of locking plate [(114.1 ±21.6)minutes):(129.8±21.4)minutes and (152.9 ±64.88)ml:(212.5 ±98.5)ml](P ＜0.05).The average fracture healing time was (17.7 ± 2.8)weeks for intramedullary nail and (20.6 ± 4.1) weeks for locking plate (P ＜ 0.05),respectively.In the intramedullary nail group,the Johner Wruhs score was excellent in 13 cases and good in four cases,with excellent and good rate of 100％,while in the locking plate group,nine cases were excellent,eight were good,and three were fair,with excellent and good rate of 85％ (P ＞ 0.05).Conclusions In terms of biomechanics and clinical effect,intramedullary nail fixation is superior than the medial locking plate fixation for the treatment of the distal tibial fractures.Intramedullary nail fixation can reduce surgical trauma and bone displacement after fixation and promote fracture healing.