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BACKGROUND:Adjustable piezoelectric effect can promote tissue regeneration and repair.Piezoelectric materials are widely used in weight-bearing tissue engineering. OBJECTIVE:To prepare a piezoelectric film material that can promote bone regeneration,and to explore its structural characterization,electrical output performance,biocompatibility,and effect of electrical output on osteogenic differentiation of rabbit bone marrow mesenchymal stem cells. METHODS:Using poly-3-hydroxybutyrateco/4-hydroxybutyrate(P34HB)as raw material,barium calcium stannate titanate powder(Ba0.94Ca0.06Sn0.08Ti0.92O3,BCST)was added according to mass ratios of 0%,5%,10%,15%,and 20%.Dichloromethane was added to solve P34HB,and the thickness of 150-200 μm BCST/P34HB piezoelectric film was prepared by vacuum drying method.After polarization in the oil bath,the surface morphology,crystal phase composition,piezoelectric coefficient and open circuit voltage were tested.The effect of BCST/P34HB electrical output at 110 Hz and 0.25 N force on the proliferation and osteogenic differentiation of rabbit bone marrow mesenchymal stem cells was tested. RESULTS AND CONCLUSION:(1)Scanning electron microscopy,X-ray diffraction,water contact angle,piezoelectric coefficient and electrical output performance tests showed that when the mass ratio of BCST increased to 20%,the BCST/P34HB piezoelectric film had good piezoelectric properties(d33=5.9 pC/N)and electrical output performance(180 mV),which was closer to the suitable range of 500 mV for electrical stimulation.(2)Live and dead staining showed that on the first day of co-culture,15%group and 20%group showed less red fluorescence.On the 5th day of culture,the number of green fluorescence in each group was significantly higher than that on the first day,and the red fluorescence was not observed in the 10%,15%and 20%groups,and only a small amount of red fluorescence was observed in the 0%and 5%groups.(3)On the 1st,3rd and 5th days of co-culture with rabbit bone marrow mesenchymal stem cells,Almar blue staining exhibited that the number of cells in each group showed an increasing trend with the increase of time.On the 5th day of culture,the number of cells in the 20%group was significantly more than that in the 0%group(P<0.05).(4)On day 10 of osteogenic induction,alkaline phosphatase staining results showed that the positive rate of the 20%group was significantly higher than that of the 0%group(P=0.000 1).On day 21,alizarin red staining and quantitative analysis of calcium nodules showed a similar trend to alkaline phosphatase staining.Compared with the 0%group,the 15%group and 20%group showed significant differences(P<0.01,P<0.000 1).(5)The results showed that 20%BCST/P34HB films had good piezoelectric properties,electrical output properties,biocompatibility and the ability of promoting osteogenic differentiation of bone marrow mesenchymal stem cells.
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Objective: To silence α-thalassemia/mental retardation syndrome XTinked gene (ATRX) in the cervical cancer HeLa cells, to detect the effect of ionizing radiation on the protein expressions of ATRX, γH2AX, Rad51 and γH2AX, Rad51 foci, and to explore the role of ATRX in DNA damage repair of the HeLa cells after irradiation. Methods: Three ATRX-shRNA and negative Control-shRNA lentiviral vectors were transfected into the 293T cells, and the Antiviruses were collected to infect the HeLa cells; puromycin was used to obtain the HeLa cells stably silencing ATRX named shAi-HeLa, shA2-HeLa, shA3-HeLa, and shCon-HeLa; the silencing efficiency was detected by Western blotting method. After ionizing radiation, the expressions of ATRX, γH2AX, and Rad51 proteins were measured by Western blotting method, and the numbers of γH2AX and Rad51 foci in shCon-HeLa and shAi-HeLa groups were observed and counted by immunofluorescence technique. Results: The ATRX protein expressed in shCon-HeLa cells, but did not express in shA1-HeLa, shA2-HeLa, and shA3-HeLa cells; it indicated that the silencing efficiency was higher. At 1, 6, and 24 h after 2 and 8 Gy irradiation, the ATRX protein expression levels in shCon-HeLa group were increased gradually; it was most at 24 h, and the ATRX was highly expressed at 1, 6, and 24 h after 8 Gy irradiation. Compared with shCon-HeLa group, at 0-6 h after 4 Gy irradiation, the number of γH2AX foci in shA1-HeLa group was significantly increased at 1 h (P<0. 05), then was gradually decreased, but the number of γH2AX foci in shA1-HeLa group was still higher at 6 h (P<0. 01). The number of Rad51 foci was consistent with the changes of γH2AX focus number. Compared with shCon-HeLa group, the number of Rad51 foci was significantly increased at 1 h (P<0. 05), and the number in shA1-HeLa group was still higher at 6 h (P<0.01). At 0-16 h after 4 Gy irradiation, compared with shCon-HeLa, the expression amounts of γH2AX and Rad51 proteins in shAi-HeLa group were increased. Conclusion: The HeLa cell models silencing ATRX are successfully obtained; ionizing radiation can cause the increase of ATRX expression level; the focus number and the protein expression amounts of γH2AX and Rad51 in HeLa cells silencing ATRX are higher than those in control group, which indicates that ATRX involves in the repair of radiation-induced DNA damage.
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Muscle strength training plays an important role in improving limb movement function, preventing muscle atrophy and promoting muscle function recovery in patients with various bone and joint diseases. The sports function of elbow joint is closely related to people's daily life activity ability. At present, Chinese muscle strength training devices are depended on import. Therefore, it is of great significance to develop muscle strength training devices. Based on the concepts and characteristics of isometric training, isotonic training, passive training and isokinetic training, in the upper computer, the servo driver and servo motor are controlled through the LabView interface, and the real-time torque is detected by the torque sensor, realizing four training modes. The main parameters of the multi-mode elbow joint muscle strength training device meet the requirements, and the trainers have a good experience.
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Humanos , Articulación del Codo , Fisiología , Fuerza Muscular , Músculo Esquelético , Entrenamiento de Fuerza , TorqueRESUMEN
BACKGROUND:The traditional methods for preparing magnesium scaffolds include casting,powder metallurgy and laser processing technology.But these methods have some defects in pore connectivity,structure complexity,and personalization.Therefore,it is of great importance to explore a new method for the preparation of porous magnesium scaffolds.OBJECTIVE:To investigate the preparation and characterization of porous magnesium scaffolds fabricated by three-dimensional (3D) printing technology.METHODS:A magnesium porous scaffold was prepared by 3D printing.The high-stability magnesium paste (consisting of magnesium powder,2-hydroxyethyl cellulose,polyethylene glycol,glycerol trioleate,ammonia,deionized water and absolute ethanol) was extruded from the pneumatic extrusion printing system to construct the scaffold,which was then sintered under protective atmosphere.The scaffold microstructure was observed by scanning electron microscope.The phase composition of scaffold was observed by X-ray diffraction.The porosity was measured by drainage method.The compressive strength was measured by universal testing machine.The degradation was studied by immersing the scaffold in saline for 30 days,and the degradation rate and the pH value of soak solution were measured at regular intervals.RESULTS AND CONCLUSION:(1) The magnesium scaffold was piled up by cylindrical filaments,and both the sizes of filaments and the pores were (450±50) μm.Also,there were many micropores in the filaments that formed the secondary pores.The porosity of the scaffold was (65.0±2.5)％ and the compressive strength was (0.87±0.15) MPa.The principal phase of the scaffold was magnesium.(2) The degradation of the scaffold continued with the soaking time,and the degradation rate showed a steady trend,which was (10±0.2) mm per year in average.The pH value of the soak solution increased in the first 5 days,and then the pH value was kept at 10.5±0.2.To conclude,3D printing technology provides a new method for porous magnesium scaffold preparation and application in bone tissue engineering.
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Objective: To evaluate the effects for vitamins preventing contrast induced nephropathy (CIN) in patients after coronary angiography (CAG) by Meta-analysis. Methods: We searched PubMed, Medline, Cochrane library central register of controlled trials and ClinicalTrails. gov from the database establishment to 2016-12 for CIN related references. According to enrollment and elimination standards, we chose eligible randomize control trail (RCT), extracted data and conducted a Meta-analysis using RevMan 5.3 statistical software. Results: A total of 11 RCTs with 1810 patients were enrolled which included in 2 groups: Vitamins group, n=951 and Placebo group, n=859. The average age of patients was (60-73) years and the male was (45.9-92.2) %. Meta-analysis showed that CIN occurrence rate in Vitamins group was lower than Placebo group (RR=0.54, 95% CI 0.39-0.73); compared with Placebo group, the incidence of CIN was decreased by 46% in Vitamins group. Using Vitamin C could decrease CIN occurrence rate (RR=0.58, 95% CI 0.37-0.90); compared with Placebo group, the incidence of CIN was decreased by 42% for using Vitamin C. Conclusion: Vitamins can reduce 46% incidence of CIN and Vitamin C may reduce 42% incidence of CIN in patients after CAG.
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Objective To investigate the safety and efficacy of a customized guide plate which is designed by digital medical technology and manufactured by 3D printing in clinical percutaneous needling at the hip joint.Methods Enrolled in this study were 9 patients with hip disorder who required hip joint needling during the period from April 2015 to August 2015.They were 7 males and 2 females,21 to 53 years of age (average,42 years).Laterality:5 left sides and 4 right sides.Conditions:4 cases of traumatic arthritis and 5 cases of osteoarthritis.All of them underwent lamellar CT scans whose data were imported into the software of Mimics 10.01 for 3D reconstruction.Then the software of 3-matic was used to design a customized guide plate on the reconstructed models.Finally,3D printing was used to manufacture the guide plate.The needle angle,direction and depth were adjusted in vitro and the operation was simulated before actual needling in clinic.After percutaneous hip joint needling was performed in the 9 patients separately,the accuracy of needling was checked using C-arm fluoroscopy.Results The percutaneous hip joint needling was performed successfully in the 9 patients in whom the customized guide plate was used.The results were consistent with what had been designed on the reconstructed models.The operation time in the 9 patients averaged 417.7 s (range,from 387 s to 590 s).Little intraoperative bleeding was observed at the site of needling,fluoroscopy was applied only once for check.No neurovascular injury or other operation-related complications occurred.Conclusion For patients who need repeated percutaneous needling at the hip joint,the customized guide plate designed by us can improve accuracy and ensure safety and efficacy of needling.