Objective To establish an efficient, simple, low cytotoxicity and cheap transfaction system. Methods We have used the cationic polymer polyethylenimine(PEI) to study transient transfection in MCF-7 cells by testing different conditions, including cell concentrations, DNA concentrations, the ratio of PEI nitrogen to DNA phosphate(PEI-N∶DNA-P) and the time of cells grown in serum-free culture together with PEI-DNA complex. Results The optimized cell concentrations were 2?10 5 cells seeded per well in 24-well dishes 18-24?h before transfection. The DNA concentrations and ratio of PEI-N∶DNA-P are very important for optimal transfection and they affect each other. For 1??g DNA per well, the optimal PEI-N∶DNA-P is about 33∶1, however, as for 4??g DNA, it is 9∶1. The best time of cells grown in serum-free culture together with PEI-DNA complex is about 5-7?h.Conclusion With optimized conditions, we can establish an efficient, simple, low cytotoxicity and cheap transfection system by using PEI.

Objective:To identify the potential impact of cervical spine kyphosis on muscle parameters, the correlation between life quality score and muscle parameters, the correlation between cervical sagittal parameters and muscle parameters.Methods:From September 30, 2019 to September 30, 2020, 30 patients diagnosed with cervical kyphosis and 34 volunteers with normal cervical curvature were enrolled in this case control study. Kyphosis group and control group were matched with sex (χ 2=0.23, P=0.75), age ( t=0.13, P=0.73), BMI ( t=0.26, P=0.20) and neck pain duration time ( t=4.67, P=0.68). Visual analogue scale (VAS) and the neck disability index (NDI) were applied. Cervical sagittal parameters and cervical range of motion (ROM) were measured on lateral radiographs of cervical spine, which included C 2-C 7 lordosis (CL), cervical sagittal vertical axis (C 2-C 7 SVA), T 1-slope (T 1S) and spinal canal angle (SCA). To evaluate muscle functions, Co-contraction ratio (CCR) was measured by surface electromyography (SEMG). Spearman method was used to analyze the correlation between life quality score, cervical sagittal parameters and CCR. Results:VAS in control group 1.4±0.9 was lower than that in kyphosis group (2.3±0.7), and therewasno statistically significant difference ( t=3.71, P=0.30). NDI in control group (4.3%±2.5%) was significantly lower than that in kyphosis group (5.8%±1.7%), and the difference was statistically significant ( t=2.60, P=0.04). CL in control group (-18.76°±2.43°) was significantly lower than that in kyphosis group (13.80°±7.59°) ( t=3.43, P<0.01). SCA in control group (85.94°±4.52°) was significantly higher than that in kyphosis group (84.07°±10.44°) ( t=0.95, P<0.01). T 1S in control group (24.00°±2.85°) was significantly higher than that of kyphosis group (15.47°±11.33°) ( t=4.25, P<0.01), and C 2-C 7 SVA of control group (30.35±6.59 mm) was significantly higher than that in kyphosis group (19.08±14.47 mm) ( t=4.09, P<0.01). ROM in control group (50.23°±3.07°) was significantly higher than that in kyphosis group (45.63°±11.73°) ( t=2.21, P<0.01). CCR from neutral to flexion movement (CCRNF) was significantly lower in control group (0.46±0.20) than kyphosis group (0.84±0.13)( t=12.61, P=0.005), CCR from extension to neutral movement (CCREN) was significantly lower in control group (0.55±0.21) than in kyphosis group (0.79±0.16) ( t=7.10, P=0.042). CCRNF was significantly correlated with VAS ( r=0.504), NDI ( r=0.322), CL ( r=-0.240), T 1S ( r=-0.591), C 2-C 7 SVA ( r=-0.474) and ROM ( r=-0.303, P<0.05). There were significant correlations between CCREN and VAS ( r=0.339), NDI ( r=0.243), CL ( r=-0.347), T 1S ( r=-0.341), C 2-C 7 SVA ( r=-0.346) and ROM ( r=-0.065) ( P<0.05). However, there was no significant difference between CCR and SCA ( P>0.05). Conclusion:SEMG canbe an objective tool to evaluate the degree of neck pain and neck disability index. During cervical flexion movement, patients with cervical kyphosis had more tensional cervical extensor muscle and worse muscle function.

Objective:To explore the correlation between cervical curve and ossification of ligaments in cranio-cervical junction and cervical spine in patients with cervical degenerative diseases.Methods:A retrospective study was conducted among 458 patients with cervical degenerative disease who underwent cervical spine X-ray and CT examinations at the Orthopedics Department of Beijing Tiantan Hospital, Capital Medical University between January 2016 and July 2020. There were 265 males and 193 females, with an average age of 57.02±10.41 years (range, 22-87 years). Patients were divided into 5 types (lordosis, straight, S-type degenerative kyphosis, R-type degenerative kyphosis and C-type degenerative kyphosis). Cervical lordosis was defined as C 2-C 7 curve <-4°, cervical kyphosis was defined as >4°, cervical straight was defined as -4° to 4°. C 2-C 7 curve, C 0-C 2 curve were measured respectively, and correlations among these imaging parameters were analyzed. CT images were used to assess the presence of ossification of ligaments in cranio-cervical and cervical spine, including ossification of the posterior longitudinal ligament, nuchal ligament, ligamentum flavum, transverse ligament, apical ligament, diffuse idiopathic skeletal hyperostosis (DISH), as well as capped dens sign (CDS), and correlations between these cervical curve and presence of ossification of ligaments were analyzed. The different grades were based on the length of the ossification of interest with respect to the distance from the posterosuperior rim of the anterior arch of the atlas to the inferior margin of the foramen magnum on mid-sagittal cervical spine CT images, Grade 3 CDS was determined when the length was more than two-thirds. Results:There were 245 patients with cervical lordosis, 114 patients with straight, 53 patients with S-type degenerative cervical kyphosis, 36 patients with R-type degenerative cervical kyphosis and 10 patients with C-type degenerative cervical kyphosis. C 0-C 2 curve showed a negative correlation with C 2-C 7 curve in all enrolled patients ( r=-0.45, P<0.001) and R-type degenerative kyphosis group ( r=-0.58, P<0.001); C 0-C 2 curve showed no correlation with C 2-C 7 curve in lordosis ( r=-0.10, P=0.124), straight ( r=-0.11, P=0.233), S-type degenerative kyphosis ( r=-0.01, P=0.943) or C-type degenerative kyphosis groups ( r=0.03, P=0.946). CDS was detected in 38.4% (176/458) of patients, and Grade 3 was detected in 17.9% (82/458) of patients. The prevalence of CDS was correlated with R-type degenerative cervical kyphosis ( r=0.10, P=0.030). Cervical kyphosis, S-type degenerative kyphosis, C-type degenerative kyphosis, C 2-C 7 curve and C 0-C 2 curve showed no correlation with ossification of the posterior longitudinal ligament, nuchal ligament, ligamentum flavum, transverse ligament, apical ligament, diffuse idiopathic skeletal hyperostosis (DISH) or different grades CDS ( P>0.05). Conclusion:R-type degenerative cervical kyphosis are more likely to correlate with the cranio-cervical curve and CDS, which is an ossification of ligament in cranio-cervical junction.

Objective:To explore sagittal parameters change of upper cervical spine after anterior cervical decompression and fusion (ACDF) and analyze the influential factors by comparison between single-, double- and multi-level surgery.Methods:In this retrospective study, 126 patients (include 60 patients with radiculopathy, 41 patients with myelopathy and 25 patients with myeloradiculopathy) who underwent ACDF between December 2016 and December 2018, were followed up at least 1year ranged from14 to 38 months, with the average of 25.6±7.2 months. 20 patients were operated by single-level ACDF, 45 patients were operated by double-level ACDF and 61 patients were operated by 3- or 4-level ACDF. Standing radiographs of cervical spine and the flexion and extension cervical X-rays were obtained in all patients at 1week before, 3 months after and 1year after operation. The Japanese Orthopaedic Association (JOA) Scores, visual analogue scale (VAS) and neck disability index (NDI) were used to evaluate the clinical effectiveness. Cervical sagittal parameters were assessed with the following parameters: the platform angle of axis (C2Slope), the cobb angle and the range of motion (ROM) of C2-7, C0-1 and C1-2.Results:All the patients obtained satisfactory clinical effects. The mean operative time of single-, double- and multi-level group were 86.4±15.5 min, 117.6±15.6 min and 170.2±28.7 min, respectively. The intraoperative blood loss of 3 groups were 16.5±5.2 ml, 37.2±30.5 ml and 63.4±41.5 ml, respectively. There was statistically significant difference between the 3 groups ( P<0.05). In the single- and double-level groups, the changes of the cobb angle and ROM of upper cervical spine between 1 week before operation and 1 year after operation was no significant difference ( P>0.05). In the multi-level group, the ROM of atlantooccipital joint (C0-1) increased significantly from 11.5°±6.1° before operation to 16.1°±13.9° 3 months and 15.3°±4.8° 1 year after operation ( P<0.05). The cobb angle of upper cervical spine and C2Slpoe was decreased significantly from 21.0°±7.6°, 6.1°±6.7° before operation to 18.6°±7.7°, 4.3°±6.9° 3 months and 19.7°±7.2°, 5.6°±6.3° 1 year after operation respectively ( P<0.05). However, there was no significant difference of cobb angle ofatlantooccipital joint between 1 week before operation and 1 year after operation ( P>0.05). Conclusion:Single- and double-level surgery makes a better ability of preserving the restoration of cervical lordosis, with little impact on the upper cervical spine, meanwhile multi-level fusion shows a negative influence on the restoration and limits the range of motion, also increases risk of surgical operation and degeneration of the atlantooccipital joint, with the increased stress distribution and range of motion.

OBJECTIVE: To investigate the effect of folic acid coated-crosslinked urethane-doped polyester elastomer (fCUPE) nerve conduit in repairing long distance peripheral nerve injury. METHODS: Thirty-six 3-month-old male Sprague Dawley rats weighing 180-220 g were randomly assigned to 3 groups, each consisting of 12 rats: CUPE nerve conduit transplantation group (group A), fCUPE nerve conduit transplantation group (group B), and autologous nerve transplantation group (group C), the contralateral healthy limb of group C served as the control group (group D). A 20-mm-long sciatic nerve defect model was established in rats, and corresponding materials were used to repair the nerve defect according to the group. The sciatic function index (SFI) of groups A-C was calculated using the Bain formula at 1, 2, and 3 months after operation. The nerve conduction velocity (NCV) of the affected side in groups A-D was assessed using neuroelectrophysiological techniques. At 3 months after operation, the regenerated nerve tissue was collected from groups A-C for S-100 immunohistochemical staining and Schwann cell count in groups A and B to compare the level of nerve repair and regeneration in each group. RESULTS: At 3 months after operation, the nerve conduits in all groups partially degraded. There was no significant adhesion between the nerve and the conduit and the surrounding tissues, the conduit was well connected with the distal and proximal nerves, and the nerve-like tissues in the conduit could be observed when the nerve conduit stents were cut off. SFI in group A was significantly higher than that in group C at each time point after operation and was significantly higher than that in group B at 2 and 3 months after operation ( P<0.05). There was no significant difference in SFI between groups B and C at each time point after operation ( P>0.05). NCV in group A was significantly slower than that in the other 3 groups at each time point after operation ( P<0.05). The NCV of groups B and C were slower than that of group D, but the difference was significant only at 1 month after operation ( P<0.05). There was no significant difference between groups B and C at each time point after operation ( P>0.05). Immunohistochemical staining showed that the nerve tissue of group A had an abnormal cavo-like structure, light tissue staining, and many non-Schwann cells. In group B, a large quantity of normal neural structures was observed, the staining was deeper than that in group A, and the distribution of dedifferentiated Schwann cells was obvious. In group C, the nerve bundles were arranged neatly, and the tissue staining was the deepest. The number of Schwann cells in group B was (727.50±57.60) cells/mm ², which was significantly more than that in group A [(298.33±153.12) cells/mm ²] ( t=6.139, P<0.001). CONCLUSION The fCUPE nerve conduit is effective in repairing long-distance sciatic nerve defects and is comparable to autologous nerve grafts. It has the potential to be used as a substitute material for peripheral nerve defect transplantation.
Rats ; Animals ; Male ; Rats, Sprague-Dawley ; Polyesters ; Peripheral Nerve Injuries/surgery* ; Elastomers ; Urethane ; Sciatic Nerve/injuries* ; Carbamates ; Nerve Tissue ; Nerve Regeneration/physiology*