Application of Multi-Rod Constructs for the Revision of Thoracolumbar Fractures.

OBJECTIVE: The revision procedure for failure of internal fixation after thoracolumbar fracture is controversial. Combined anterior and posterior surgery is associated with higher risk more intraoperative bleeding and tissue damage. The success rate of simple anterior surgery needs further confirmation, and posterior surgery lacks stability of internal fixation. This study evaluates the feasibility and surgical effect of multi-rod constructs in the revision of thoracolumbar fractures. METHODS: Eleven patients with thoracolumbar fractures who underwent previous construct failure and were treated with revision and internal fixation with the multi-rod technique from March 2017 to September 2018 were analyzed. The original internal fixation was removed and replaced in the medial insertion of satellite rods and bone graft. The average follow-up time was 15.97 months. The intraoperation blood loss, the time of the operation, activation and discharge and the rate of rod fracture were calculated. The sagittal Cobb angle before revision, after revision and at the last follow-up were compared. The clinical effect was evaluated by visual analogue scale (VAS) and Oswestry Disability Index questionnaire (ODI). RESULTS: The average operation time was 107 min, the intraoperative blood loss was 131.81 mL, the active time was 1.59 days, and the discharge time was 10.89 days. No rod fractured again during the follow-up period. The paired t-test was used to compare the Cobb angle, VAS score, and ODI before and after surgery. There was significant difference in the sagittal Cobb angle between the pre-revision and the posterior sagittal position (p = 0.000), and no significant difference was found between post-revision and last follow-up (p = 0.551). VAS and ODI were greatly improved at the last follow-up. CONCLUSION: The literature on revision of thoracolumbar fractures is insufficient and comprises varying opinions. This paper proposes a new treatment option. The application of the multi-rod constructs in the revision of thoracolumbar fractures is safe, simple, and effective and might provide guidance for future clinical work.

What happens to the osteoporotic bone mesenchymal stem cells? Evidence from RNA sequencing.

Evidence presented that osteoporosis is closely related to the dysfunction of bone mesenchymal stem cells (BMSCs). But most studies are insufficient to reveal what actually happens to the osteoporotic BMSCs. In this study, BMSCs were harvested from ovariectomized and sham-operated rats. After checking the characteristics of rat models and stem cells, the BMSCs were carried out for RNA sequencing. Part of the findings were verified that seven mRNAs (Abi3bp, Aifm3, Ccl11, Cdkn1c, Chst10, Id2, Vcam1) were significantly up-regulated in osteoporotic BMSCs while seven mRNAs (Cep63, Fgfr3, Myc, Omd, Pou2f1, Smarcal1, Timm10b) were down-regulated. In addition, potential miRNA-mRNA and lncRNA-mRNA regulatory networks were illustrated. The changes in osteoporotic BMSCs covered a large set of biological processes, including cell viability, differentiation, immunoreaction, bone repairment and estrogen defect. This study enriched the pathophysiological mechanisms of BMSCs and osteporosis, as well as provided dozens of attractive RNA targets for further treatment.

Measurement and Simulation of Risk Coupling in Port Hazardous Chemical Logistics.

Hazardous chemical logistics and transportation accidents are the main type of port safety accidents. Correctly and objectively analyzing the causes of port hazardous chemical logistics safety accidents and the coupling mechanisms of risk generation are very important for reducing the occurrence of port hazardous chemical safety accidents. Based on the causal mechanism and coupling principle, in this paper, we construct a risk coupling system for port hazardous chemical logistics and analyze the coupling effects in the risk system. More specifically, a personnel-ship-environment-management system is established and the coupling between the four systems is explored. Taking Tianjin Port as an example, the risk coupling factors are analyzed in combination with system dynamics simulation. Under dynamic changes in coupling coefficients, the change of coupling effects are explored more intuitively, the logical relationships between logistics risks are analyzed and deduced, a comprehensive view of the coupling effects and their evolution process in accidents is provided, and the key causes of accidents and their coupling risk effects are identified. For port hazardous chemicals logistics safety accidents, the presented results not only allow for effective analysis of the causes of safety accidents, but also provide reference for the formulation of prevention strategies.

Differentiation of mesenchymal stem cells towards a nucleus pulposus-like phenotype utilizing simulated microgravity In vitro.

Mesenchymal stem cells (MSCs) were induced into a nucleus pulposus-like phenotype utilizing simulated microgravity in vitro in order to establish a new cell-based tissue engineering treatment for intervertebral disc degeneration. For induction of a nucleus pulposus-like phenotype, MSCs were cultured in simulated microgravity in a chemically defined medium supplemented with 0 (experimental group) and 10 ng/mL (positive control group) of transforming growth factor ß1 (TGF-ß1). MSCs cultured under conventional condition without TGF-ß1 served as blank control group. On the day 3 of culture, cellular proliferation was determined by WST-8 assay. Differentiation markers were evaluated by histology and reverse transcriptase-polymerase chain reaction (RT-PCR). TGF-ß1 slightly promoted the proliferation of MSCs. The collagen and proteoglycans were detected in both groups after culture for 7 days. The accumulation of proteoglycans was markedly increased. The RT-PCR revealed that the gene expression of Sox-9, aggrecan and type II collagen, which were chondrocyte specific, was increased in MSCs cultured under simulated microgravity for 3 days. The ratio of proteoglycans/collagen in blank control group was 3.4-fold higher than positive control group, which denoted a nucleus pulposus-like phenotype differentiation. Independent, spontaneous differentiation of MSCs towards a nucleus pulposus-like phenotype in simulated microgravity occurred without addition of any external bioactive stimulators, namely factors from TGF-ß family, which were previously considered necessary.

Differentiation of Mesenchymal Stem Cells towards a Nucleus Pulposus-like Phenotype Utilizing Simulated Microgravity In Vitro / 华中科技大学学报（医学）（英德文版）

Mesenchymal stern cells (MSCs) were induced into a nucleus pulposus-like phenotype utilizing simulated microgravity in vitro in order to establish a new cell-based tissue engineering treatment for intervertebral disc degeneration.For induction of a nucleus pulposus-like phenotype,MSCs were cultured in simulated microgravity in a chemically defined medium supplemented with 0 (experimental group) and 10 ng/mL (positive control group) of transforming growth factor β1 (TGF-β1).MSCs cultured under conventional condition without TGF-β1 served as blank control group.On the day 3 of culture,cellular proliferation was determined by WST-8 assay.Differentiation markers were evaluated by histology and reverse transcriptase-polymerase chain reaction (RT-PCR).TGF-β1 slightly promoted the proliferation of MSCs.The collagen and proteoglycans were detected in both groups after culture for 7 days.The accumulation of proteoglycans was markedly increased.The RT-PCR revealed that the gene expression of Sox-9,aggrecan and type Ⅱ collagen,which were chondrocyte specific,was increased in MSCs cultured under simulated microgravity for 3 days.The ratio of proteoglycans/collagen in blank control group was 3.4-fold higher than positive control group,which denoted a nucleus pulposus-like phenotype differentiation.Independent,spontaneous differentiation of MSCs towards a nucleus pulposus-like phenotype in simulated microgravity occurred without addition of any external bioactive stimulators,namely factors from TGF-β family,which were previously considered necessary.