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Objective:To prepare PEG-SH modified GNPs/miR-29 nanoparticles and to investigate the proliferation and differentiation of neural stem cells induced by PEG-SH modified GNPs/miR-29 nanoparticles.Methods:PEG-SH modified GNPs/miR-29 nanoparticles were developed by oxidation-reduction method and were tested for UV absorption spectrum, particle size distribution and zeta potential of nanoparticles. A total of 15 adult male Sprague Dawley (SD) rats were used to establish spinal cord injury model by modified Allen method. The artificial miR-29 and PEG-SH modified GNPs/miR-29 nanoparticles were implanted into the injury site of spinal cord respectively. The stability of miR-29 expression was analyzed by gel electrophoresis. The neural stem cells were isolated and cultured from 10 SPF grade neonatal rats. It was identified by Nestin, GFAP and NSE antibodies. The activity and proliferation of neural stem cells in synthetic miR-29, PEG-SH GNPs and PEG-SH GNPs/miR-29 nanoparticles group was detected by CCK-8 assay. Neural stem cells were cultured with synthetic miR-29, PEG-SH GNPs and PEG-SH GNPs/miR-29 nanoparticles for 1 week. The density, length and number of neuritis were investigated.Results:The solution of PEG-SH modified GNPs showed a brownish red appearance. The spheres were in uniform distribution under transmission electron microscope. The results of UV absorption spectrum showed a single peak wave. The peak value of UV absorption was near 523 nm. The zeta potential increased gradually with the increased content of PEG-SH. The peak value of zeta potential was 22.5±5.2 mV. With the increase of content of PEG, the particle size of PEG-SH modified GNPs rapidly reached peak value at the early stage and then decreased rapidly to a relatively stable level. The synthetic miR-29 and PEG-SH modified GNPs/miR-29 nanoparticles were implanted into the injury site of spinal cord. At 0-6 h, clear band was observed in the synthetic miR-29 group. However, the band was disappeared rapidly at 12-24 h. In PEG-SH GNPs/miR-29 group, clear band were always observed. The OD values of miR-29 group were 0.34±0.17, 0.78±0.31, 1.28±0.68, 1.64±0.38 at 1, 3, 5 and 7 d after inoculation respectively. There was no significant difference in OD values compared with DMEM group. There was no significant difference in OD values among GNPs, PEG-SH GNPs, PEG-SH GNPs/miR-29 and DMEM group. The density (56.38±3.65 μm 2), length (78.25±3.72 μm) and the number [(356±34.52) /1,000×high power field] of neurites in PEG-SH GNPs/miR-29 group were higher than those in miR-29 group, PEG-SH modified GNPs group and saline group. However, there was no significant difference in the density, length and number of neurite between PEG-SH GNPs/miR-29 and serum group. Conclusion:PEG-SH modified GNPs/miR-29 nanoparticless have good biological properties. It can induce the proliferation and differentiation of neural stem cells with protective effects on miR-29.
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Objective To compare the biomechanical stability of different fixation methods for unstable pelvic fractures, so as to provide references for clinical treatment. Methods An unstable pelvic fracture model (Tile C) with the sacroiliac joint dislocation at one side and the pubic rami fracture was constructed via three-dimensional finite element method. In the front of the pelvis, the fracture models were fixed with anterior pelvic Stoppa approach (ASA),subcutaneous anterior pelvic approach (APA), anterior pelvic ilioinguinal approach (AIA) and anterior pelvic external fixation (AEF),and the rear was fixed with sacroiliac joint screw (SIJS）and posterior tension-band plate (PTP). The Von Mises stress and strain distributions of fracture models fixed by different combinations of fixation approaches were analyzed under simulated standing conditions. Results After the models were applied with 500 N vertical load, the maximum stresses at the fracture sites were all reduced, which were smaller than 10 MPa in the front of the pelvis. The maximum stress at the anterior and posterior part of implants in sequence was ASA＜AIA＜AEF＜APA, and the average displacement under the same stress in sequence was ASA＜AIA＜AEF＜APA. Meanwhile, the maximum stresses at the sacroiliac joint and the posterior part of implants in PTP group were significant smaller than those in SIJS group, and the maximum total displacement and vertical displacement in PTP group were also smaller than those in SIJS group. Conclusions Unstable pelvic fractures could be significantly improved when the fracture was fixed by implants in eight combined methods. However, the overall biomechanical properties of the AIA groups were superior to those of the AEF groups and the APA groups. The stability of PTP groups in the treatment of posterior injury was better than that of SIJS groups.
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Objective To evaluate the effect of electrical stimulation of the pelvic floor muscles combined with bladder training on urinary dysfunctionafter incomplete spinal cord injury.Methods Sixty-two incomplete spinal cord injury patients who had received an operation between November 2009 and December 2014 were enrolled and divided randomly into a control group (n=32) and a treatment group (n =30).Both groups were treated with conventional intermittent catheterization,while the treatment group was additionally given electrical stimulation of the pelvic floor muscles combined with bladder training.The residual urine volume was recorded before and after the treatment.Uurodynamic examinations were conducted,and the rate of successful catheter extraction and of urinary tract infection on the 15th and 30th day of treatment,were recorded and analyzed.Results All of the patients were followed-up for an average of 18.5 months.Significant improvement was observed in the residual urine volume,the maximum or average urinary flow rate,and the detrusor pressure at peak flow of both groups.However,at the end of follow-up the treatment group recorded significantly better results on all these measures than the control group.The successful catheter extraction rate of the treatment group (96.7％) was significantly higher than that of the control group and their average number of catheterization days was significantly fewer.The urinary tract infection rates on the 15th and 30th day of treatment were 16.7％ and 6.7％ in the treatment group,significantly lower than in the control group.Conclusions Electrical stimulation of the pelvic floor combined with bladder training significantly improves urination function after an operation for incomplete spinal cord injury,decreases the days of catheterization and lowers the rate of urinary tract infection.Such combined therapy is worth promoting in clinical practice.
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Objective To compare the clinical effects of open kinetic chain (OKC) exercises with those of closed kinetic chain (CKC) exercises and limited open kinetic chain combined with closed kinetic chain exercises on rehabilitation after the anterior cruciate ligament reconstruction.Methods Ninety-four patients recovering from single-bundle anterior ligament reconstructions were enrolled and randomly divided into an OKC group (n =33),a CKC group (n =30) or a limited open kinetic chain combined with closed kinetic chain group (combined group) (n =31).Lysholm score,International Knee Documentation Committee (IKDC) score,KT-1000,and active and passive range of motion were evaluated for the 3 groups three and six months after the surgery.Results Three months after surgery,significant differences were found among the 3 groups in Lysholm scores [(87.00±4.79),(83.67± 3.55) and (86.71±3.62) respectively],IKDC scores [(89.45±4.79),(86.40±3.76) and (88.58±3.60) respectively],KT-1000[(1.99±0.30),(1.05±0.26) and (1.02±0.24) mm],as well as active and passive range of motion [(10.06±2.06),(7.73±1.41) and (8.10±1.35) mm;(9.76±2.26),(7.87±1.89) and (8.39±1.62) mm] (P＜ 0.05).Six months after surgery,no significant differences were found in Lysholm scores and IKDC scores(P＞0.05),but significant differences were found in KT-1000,and active and passive range of motion(P＜0.05) compared to those at 3 months after surgery.Moreover,there were no significant differences between the OKC and combined groups in Lysholm scores and IKDC scores(P＞0.05),but significant differences between them in active and passive range of motion (P＜0.05).There were no significant differences between the CKC and combined groups in Lysholm scores,IKDC scores,KT-1000,and active and passive range of motion(P＜0.05).Conclusion Combining limited open kinetic chain exercise with closed kinetic chain exercise is safe and reliable in the rehabilitation after anterior cruciate ligament reconstruction.
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Objective To evaluate the accuracy of thoracic pedicle screw placement using the "funnel technique" and investigate its consistency in experimental study and clinical application.Methods The clinical data of three human cadavers and 11 patients with the installation of at least one thoracic pedicle screw at T1 -T12 from August 2006 to July 2008 were retrospectively analyzed. One junior spine surgeon lack of experience were responsible for placing these screws with the "funnel technique".The accuracy of screw placement and the complications related to the use of thoracic pedicle screws were analyzed by assessing postoperative CT scans. Results The mean follow-up time was 23.1 months,which showed no vascular or visceral complications, or iatrogenic neurological injury. The rate of unintended cortex perforations was 14% (10/72) in cadavers and 15% (8/55) in patients, respectively.The critical perforation occurred in two screws (3%) in cadavers and one screw (2%) in patients. There was no statistical difference between the percentage of cortex perforations in cadavers and patients. Of all the 11 patients, screw violation occurred laterally in six ( 11% ), medially in one ( 2% ) and superiorly in one (2%). No violations occurred inferiorly or anteriorly. For all patients, only one screw needed revision. The perforations made by the junior spine surgeon occurred in six screws in the first cadaver, three in the second cadaver and one in the third cadaver. Conclusions The "funnel technique" is a simple,safe, accurate and cost-effective technique for pedicle screw placement. The result of the experimental study is consistent with that of the clinical application. "funnel technique" is helpful for junior spine surgeons to master the technique of thoracic pedicle screw placement.