3D-Printed Magnesium Peroxide-Incorporated Scaffolds with Sustained Oxygen Release and Enhanced Photothermal Performance for Osteosarcoma Multimodal Treatments.

The hypoxic microenvironment in osteosarcoma inevitably compromises the antitumor effect and local bone defect repair, suggesting an urgent need for sustained oxygenation in the tumor. The currently reported oxygen-releasing materials have short oxygen-releasing cycles, harmful products, and limited antitumor effects simply by improving hypoxia. Therefore, the PCL/nHA/MgO2/PDA-integrated oxygen-releasing scaffold with a good photothermal therapy effect was innovatively constructed in this work to achieve tumor cell killing and bone regeneration functions simultaneously. The material distributes MgO2 powder evenly on the scaffold material through 3D printing technology and achieves the effect of continuous oxygen release (more than 3 weeks) through its slow reaction with water. The in vitro and in vivo results also indicate that the scaffold has good biocompatibility and sustained-release oxygen properties, which can effectively induce the proliferation and osteogenic differentiation of bone mesenchymal stem cells, achieving excellent bone defect repair. At the same time, in vitro cell experiments and subcutaneous tumorigenesis experiments also confirmed that local oxygen supply can promote osteosarcoma cell apoptosis, inhibit proliferation, and reduce the expression of heat shock protein 60, thereby enhancing the photothermal therapy effect of polydopamine and efficiently eliminating osteosarcoma. Taken together, this integrated functional scaffold provides a unique and efficient approach for antitumor and tumor-based bone defect repair for osteosarcoma treatment.

Risk factors for multidrug-resistant bacteria recurrent infections in orthopedic patients from 2011 to 2017 / 中华创伤骨科杂志

Objective To explore the clinical characteristics of multidrug-resistant organisms (MDROS) and analyze the risk factors for MDROS recurrent infections in orthopedic in-patients.Methods A retrospective study was conducted of the clinical data of 296 in-patients with MDROS infection from June 2011 to August 2017.They were 216 males and 80 females with an average age of 49.9 years.Their average hospital stay was 37.2 days.Univariate analysis was conducted for items like age,hospital stay,bedridden time,concomitant internal disease (chronic obstructive pulmonary disease,chronic cardiovascular disease and diabetes),open or closed fracture,uninary catheter,use of hormone,stay in ICU,implantation material,incision grade,albumin level,hemoglobin level,reoperation,type of antibiotics and duration of antibiotics use.Multivariate logistic regression analysis was performed using SPSS 20.0 for items with significant differences.Results A total of 352 strains of pathogens were isolated,including methicillin-resistant staphylococcus aureus (26.7％),extended-spectrum β-lactamase-producing Escherichia coli (24.4％) and multidrug-resistant acinetobacter baumannii (24.1％).The pathogens were observed mostly at surgical sites (34.1％) and open wounds (23.0％).Forty-two patients reinfected the same strain after treatment.The multivariate logistic regression analysis revealed the following as the independent risk factors for MDROS recurrent infections in the orthopedic in-patients:hospital stay [OR =4.918,95％ CI (1.642,14.731),P =0.004],long bedridden time [OR=3.583,95％ CI (1.081,11.876),P=0.037],open injury [OR=2.375,95％CI (1.291,4.368),P=0.005],diabetes [OR=6.360,95％ CI (2.112,19.149),P=0.001],and chronic obstructive pulmonary disease [OR=4.170,95％ CI (1.419,12.251),P=0.009].Conclusions To prevent recurrent MDROS infections in orthopedic patients,surgeons should shorten unnecessary hospital stay,encourage ambulation as early as possible,effectively control blood sugar and actively treat concomitant internal diseases in addition to regular use of antibiotics.

The experimental study on repair of rat femoral condyle defect with peripheral blood mesenchymal stem cells combined with absorbable gelatin sponge-self assembling peptide / 实用医学杂志

Objective This study aimed to explore the effect of peripheral blood mesenchymal stem cells combined with porous absorbable gelatin sponge/self assembling peptide composite scaffolds on SD rat femoral con-dyle bone defect reconstruction and provide a new strategy for the repair of bone defects. Methods 30 female SD rats,8W age,were randomly divided into 3 groups,10 every group.The group A was blank control group,group B was porous absorbable gelatin sponge/self assembling peptide composite scaffold group,and group C was periph-eral blood mesenchymal stem cells combined with porous absorbable gelatin sponge/self assembling peptide compos-ite scaffold group. The effect of osteogenesis was observed by paraffin section,hematoxylin eosin staining,X-ray examination,and Micro-CT scanning in 3 dimensional reconstruction of femoral condyle defect. Results Imaging examination showed that the experimental group had better osteogenesis effect. Histological examination showed that a lot of new bone tissue was found in group C,while only a small amount of new bone was found in the group of A and B. Conclusions The experiment shows that peripheral blood mesenchymal stem cells as the seed cells for tissue engineering,combined with porous absorbable gelatin sponge-self assembling peptide has better ability to repair bone defects,and has good application prospect,which is worthy of further research.