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BACKGROUND: Studies have confirmed that monosialotetrahexosyl anglioside can induce human umbilical cord mesenchymal stem cells to differentiate into neuron-like cells, but little is reported on its optimal concentration. OBJECTIVE: To explore the optimal concentration of monosialotetrahexosyl ganglioside that induces human umbilical cord mesenchymal stem cells to differentiate into neuron-like cells in vitro. METHODS: Human umbilical cord mesenchymal stem cells were isolated by using collagenase digestion method, and after expansion, passage 3 cells were randomly allocated into five groups. When 70%-80% of cells were confluent, 50, 100, 150 and 200 mg/L monosialotetrahexosyl ganglioside induction solutions were added in corresponding experimental groups, while cells in the blank control group were cultured in the same volume of L-DMEM medium. Cell morphology was observed under inverted phase contrast microscope. Expression levels of microtubule-associated protein 2, neurofilament protein and glial fibrillary acidic protein were measured by using immunohistochemistry at 6 hours after induction. RESULTS AND CONCLUSION: Human umbilical cord mesenchymal stem cells were isolated successfully and sub-cultured stably. These cells could express surface markers of mesenchymal stem cells. Monosialotetrahexosyl ganglioside at the optimal concentration of 150 mg/L was confirmed to induce the neuron-like differentiation of human umbilical cord mesenchymal stem cells, and differentiated cells could express microtubule-associated protein 2 and neurofilament protein as neuron-specific markers. [ABSTRACT FROM AUTHOR]

BACKGROUND: With the development of tissue engineering, 3D bioprinting technology is used to prepare skin scaffolds. The process parameters are however unclear, and stacking and discontinuities often occur during the printing process. OBJECTIVE: To conduct the numerical simulation by 3D bio-printer and finite element software Fluent so as to obtain reasonable extrusion pressure, viscosity, nozzle walking speed, nozzle diameter and temperature parameters to solve the problem of accumulation and discontinuity in the printing process of gelatin fibers. METHODS: Using 5% gelatin cellulose solution as the printing material, the numerical simulation was carried out by using 3D bio-printer and software Fluent. The printing temperature was set at 5, 15, 25 oC, and the printing pressure was 0.16, 0.18, 0.2 MPa, respectively. The flow rate and flow at the tip of the nozzle were measured at 0.21, 0.26, and 0.41 mm. The gelatin fiber skin bio-scaffold was 3D-printed with appropriate parameters, and the scaffold structure was observed by scanning electron microscopy. RESULTS AND CONCLUSION: When the printing temperature was set at 15 oC, the nozzle walking speed was 30 mm/s, the pressure was 0.18 MPa, and the nozzle diameter was 0.21 mm, the gelatin fiber material could be continuously extruded but not stacked or broken. Under the above printing conditions, the width of printed filament was about 1 400 μm. For the biological scaffold printed under this condition, the row and column distribution of the scaffold was more uniform shown by the scanning electron microscope, and the bonding site between the layers was firmly bonded and not easily deformed. The porosity of the scaffold was about 57%. [ABSTRACT FROM AUTHOR]

BACKGROUND: Alcohol inactivated replantation is widely used in the treatment of malignant bone tumors, but the postoperative bone healing is little reported. OBJECTIVE: To analyze the related factors affecting the bone healing of the autograft bone after alcohol inactivated replantation. METHODS: Twenty-one patients with malignant bone tumor who received alcohol-inactivated autograft bone replantation were enrolled, including 8 males and 13 females with an age of 7-56 years. Among which, 17 cases underwent plate-screw internal fixation, and 4 cases received intramedullary nailing fixation. All patients were followed up to observe the bone healing. The related factors of the autograft bone healing were analyzed. RESULTS AND CONCLUSION: (1) The follow-up time was 2-6 years, with an average of 3.8 years. (2) Eleven patients (1 male and 10 females, with an average age of 20.8 years) achieved bone union, the average length of autograft bone was 17.36 cm, all fixed using plates, and the average healing time was 20 months. (3) Bone nonunion occurred in 10 patients (7 males and 3 females, with an average age of 20.5 years), the average length of autograft bone was 16.10 cm, 4 cases of intramedullary nailing fixation, and 6 cases of plate-screw fixation. (4) The differences in the average age and average length of autograft bone were insignificant between two groups. The sex and internal fixation ways showed significant differences between two groups (P < 0.05). (5) These results suggest that the age and the length of the autograft bone have no significant effect on autograft bone healing. The female patients and plate-screw internal fixation are beneficial for bone healing after alcohol inactivated replantation. [ABSTRACT FROM AUTHOR]