Surface Modification Techniques to Produce Micro/Nano-scale Topographies on Ti-Based Implant Surfaces for Improved Osseointegration.

Titanium and titanium alloys are used as artificial bone substitutes due to the good mechanical properties and biocompatibility, and are widely applied in the treatment of bone defects in clinic. However, Pure titanium has stress shielding effect on bone, and the effect of titanium-based materials on promoting bone healing is not significant. To solve this problem, several studies have proposed that the surface of titanium-based implants can be modified to generate micro or nano structures and improve mechanical properties, which will have positive effects on bone healing. This article reviews the application and characteristics of several titanium processing methods, and explores the effects of different technologies on the surface characteristics, mechanical properties, cell behavior and osseointegration. The future research prospects in this field and the characteristics of ideal titanium-based implants are proposed.

Large Scale Identification of Osteosarcoma Pathogenic Genes by Multiple Extreme Learning Machine.

At present, the main treatment methods of osteosarcoma are chemotherapy and surgery. Its 5-year survival rate has not been significantly improved in the past decades. Osteosarcoma has extremely complex multigenomic heterogeneity and lacks universally applicable signal blocking targets. Osteosarcoma is often found in adolescents or children under the age of 20, so it is very important to explore its genetic pathogenic factors. We used known osteosarcoma-related genes and computer algorithms to find more osteosarcoma pathogenic genes, laying the foundation for the treatment of osteosarcoma immune microenvironment-related treatments, so as to carry out further explorations on these genes. It is a traditional method to identify osteosarcoma related genes by collecting clinical samples, measuring gene expressions by RNA-seq technology and comparing differentially expressed gene. The high cost and time consumption make it difficult to carry out research on a large scale. In this paper, we developed a novel method "RELM" which fuses multiple extreme learning machines (ELM) to identify osteosarcoma pathogenic genes. The AUC and AUPR of RELM are 0.91 and 0.88, respectively, in 10-cross validation, which illustrates the reliability of RELM.

An LC-MS/MS method for determination of curculigoside with anti-osteoporotic activity in rat plasma and application to a pharmacokinetic study.

A rapid, simple, selective and sensitive LC-MS/MS method was developed for the determination of curculigoside in rat plasma. The analytical procedure involves extraction of curculigoside and syringin (internal standard, IS) from rat plasma with a one-step extraction method by protein precipitation. The chromatographic resolution was performed on an Agilent XDB-C18 column (4.6 × 50 mm, 5 µm) using an isocratic mobile phase of methanol with 0.1% formic acid and H2 O with 0.1% formic acid (45:55, v/v) at a flow rate of 0.35 mL/min with a total run time of 2.0 min. The assay was achieved under the multiple-reaction monitoring mode using positive electrospray ionization. Method validation was performed according to US Food and Drug Administration guidelines and the results met the acceptance criteria. The calibration curve was linear over 4.00-4000 ng/mL (R = 0.9984) for curculigoside with a lower limit of quantification of 4.00 ng/mL in rat plasma. The intra- and inter-day precisions and accuracies were 3.5-4.6 and 0.7-9.1%, in rat plasma, respectively. The validated LC-MS/MS method was successfully applied to a pharmacokinetic study of curculigoside in rats after a single intravenous and oral administration of 3.2 and 32 mg/kg. The absolute bioavailability of curculigoside after oral administration was 1.27%.

[Changes of cdk5, p35 and p53 gene expression levels in arsenic-induced neural cell apoptosis].

OBJECTIVE: To study the expression levels of cdk5, p35 and p53 genes in arsenic trioxide (As2O3O)-induced neuron apoptosis and to explore the potential mechanism. METHODS: The cultured primary rats' neurons were divided into 5 groups, which were exposed to 0, 1, 5, 10 micromol/L As2O3 and dimethyl sulfoxide (DMSO) for 8 h, respectively. The cell viability and cell apoptosis were detected by MTT colouration methods and flow cytometry, respectively. The real-time fluorescence quantitative PCR was used to measured the expression levels of cdk5, p35 and p53 genes. RESULTS: The cell viability inhibition rates were 16.77%, 19.72% and 27.81% in 1, 5, 10 micromol/L As203 groups, respectively. Compared to the untreated group and DMSO group, the cell apoptosis rates were significantly increased in 5 and 10 micromol/L As2O3 groups (P < 0.05). The expression levels of cdk5, p35 and p53 genes increased with the exposure doses of AsO3. However, there were no significant differences in p35 gene expression between different dose subgroups (P > 0.05). There were significant differences in cdk5 and p53 gene expression between different dose subgroups (P < 0.05). The expression levels of cdk5 gene in 5 and 10 micromol/L As2O3 groups were significantly higher than those in untreated group and DMSO group (P < 0.05). The expression levels of p53 gene in 1, 5 and 10 micromol/L As2O3 groups were significantly higher than that in untreated group (P < 0.05). The expression level of p53 gene in 10 mciromol/L As2O3 group was significantly higher than that in DMSO group (P < 0.05). CONCLUSION: Cdk5, p35 and p53 genes may involve in the process of As2O3-induced neural cell apoptosis.