BACKGROUND: Bone tissue engineering plays a very important role in the repair of bone defects, which can deliver bioactive substances, promote bone tissue growth and repair bone defects. Bone scaffolds act as one of the three elements of bone tissue engineering. Three-dimensional (3D) printing technology can achieve individualized bone tissue repair through customized artificial bone preparation.OBJECTIVE: To analyze the biological characteristics of several commonly used bone tissue engineering scaffolds and to explore the application of 3D printing technique in the construction of bone tissue engineering scaffolds.METHODS: The literatures of PubMed and Wanfang database related to bone tissue engineering scaffold materials and 3D printing technology were retrieved from 2005 to 2016. The Keywords were tissue engineering scaffold, bone defects,polymer materials, bioceramics, metal materials, composite materials, 3D printing in English and Chinese, respectively,which would appear simultaneously in title and abstract. Repetitive articles were excluded and finally 65 articles were included in result analysis.RESULTS AND CONCLUSION: The commonly used bone tissue engineering scaffold materials include polymer materials (natural and macromolecule polymeric materials), bioceramics, and metal materials. According to the characteristics of the materials, composite materials made of different materials can compensate for the shortcomings of a single material, and then developed into new tissue engineering scaffold materials. For the tissue engineering bone production, 3D printing technologies include melt deposition technology, selective laser sintering technology, low temperature deposition manufacturing technology, and etc. When the 3D printing technology is used to prepare a bone tissue engineering scaffold, the use of powder or adhesive must have limited conditions, such as flowability, stability and wettability. Powder materials used for 3D printing can be divided into synthetic polymers, natural macromolecules,bioceramics and their mixtures, with different advantages and disadvantages. Ultimately, the bone engineering scaffolds produced by 3D printing technology have unique advantages in mechanics, structure and individuality, and have wide application prospect in the manufacture of bone scaffolds.

Objective To investigate the prevalence of DUOX2 mutations in Chinese patients with congenital hypothyroidism (CH) and to discuss the inheritance pattern of DUOX2 gene.Methods Blood samples were collected from 91 CH children and their genomic DNA was extracted from peripheral blood leukocytes.All exons and exon-intron boundaries of DUOX2 were analyzed by target next-generation sequencing and family trios was established to study the inheritance pattern of DUOX2 gene.Results Fifty-four out of 91 children with CH carried DUOX2 mutation, with a prevalence of 59.34%.Of the 54 CH children, 36 carried DUOX2 biallelic mutations.In all 12 family trios with probands carrying biallelic DUOX2 mutations, the parents carried heterozygous DUOX2 mutations while still showing normal thyroid function, suggesting that CH caused by DUOX2 mutations is inherited in an autosomal recessive manner.Conclusion DUOX2 gene is one of the most frequently mutated genes in Chinese CH patients and its inheritance pattern is an autosomal recessive one.

Objective:To construct single-cell transcription landscape of T cell in peripheral blood mononuclear cells(PBMCs) and thyroid tissue of patients with Hashimoto ′s thyroiditis(HT), and to analyze the changes in the proportion and functionality of T cell clusters in HT disease state.Methods:Single cell RNA sequencing was performed on PBMCs and thyroid tissue from 5 HT patients. Single cell RNA sequencing data of PBMCs from 5 healthy individuals were retrieved from public databases. After preliminary clustering, the clusters expressing CD3E were extracted and clustering again, and the names of each cluster were determined according to the known cell markers. The proportion of each cell subtype was compared, and the differentially expressed genes in different samples were analyzed.Results:After quality control, the 71 533 T cells were classified into 19 cell clusters. Among them, the proportion and function of C1_CD4 + Naive T cell clusters, C3_CD4 + Treg cell clusters, C7_CD8 + Naive T cell clusters, C8_GNLY -CD8 + T cell clusters, C10_RORC + CD8 + T cell clusters, C11_ GZMK + CD8 + T cell clusters, C12_CCL4 + CD8 + T cell clusters, and C18_PTGDS + NK cell clusters in thyroid tissue of HT patients were significantly different from those in PBMCs of healthy controls and HT patients. Conclusion:The proportion of multiple T cells in thyroid tissue of HT patients were significantly different from those in PBMCs. Among them, the proportion of three of CD8 + T cell subsets with high expression of cell killing-related genes in thyroid tissue T cells of HT patients is higher than that in PBMCs T cells, and it is statistically significant. In addition, the functionality of various T cells in the thyroid tissue of HT patients are also significantly different from those in PBMCs. A cluster of GZMK + CD8 + T cells showes significantly lower expression of genes related to PD1 pathway in thyroid tissues of HT patients compared with cells in PBMCs of HT patients, also a cluster of CCL4 + CD8 + T cells showes significantly lower expression of genes related to IL-12 pathway.