[Development and in vivo biomechanics of goat mobile artificial lumbar spine complex].

OBJECTIVE: Mobile artificial lumbar complex (MALC) which suitable for reconstruction after subtotal lumbar resection in goats was developed,and to test stability of the complex and postoperative lumbar segmental motor function. METHODS: Eighteen male boer goats aged from 1 to 2 years old (weighted from 35 to 45 kg) were selected and divided into control group,fusion group and non-fusion group,with 6 goats in each group. According to preoperative CT scans and MRI examinations of lumbar,the goat MALC was designed and performed by 3D printed for non-fusion group. Operation was performed on three groups respectively,and only vertebral body and disc were exposed in control group. In fusion group,L4 part of vertebral body and the upper and lower complete disc tissues were removed,and the lumbar spine bone plate fixation was performed with titanium mesh bone grafting. In non-fusion group,vertebral body and disc were removed in the same way,and MALC was implanted. AP and lateral X-rays of lumbar vertebrae in goat were taken at 6 months after surgery,in order to understand whether the plant was dislocated,displaced and fractured. Biomechanical tests were performed on the specimens by mechanical instrument to measure range of motion (ROM) of L2,3,L3,4,L4,5 intervertebral space and the overall ROM of L2-5 lumbar vertebrae. RESULTS: MALC of lumbar vertebra was designed by 3D printing,and its component artificial vertebrae and upper and lower artificial end plates were manufactured. The semi-spherical structure was fabricated by precision lathe using high-crosslinked polyethylene material,and the prosthesis was assembled. Postoperative AP and lateral X-rays of lumbar vertebra at 6 months showed the implant position of implant and MALC were good without displacement and dislocation. In vitro biomechanical test of lumbar vertebrae specimens:(1) There were no statistical significance in ROM of lumbar intervertebral space flexion and extension,lateral flexion and rotation on L3,4 and L4,5,between non-fusion group and control group (P>0.05),while ROM of fusion group was significantly reduced compared with the other two groups (P<0.05). There were no significant difference in ROM of L2,3 intervertebral flexion and extension,lateral flexion and rotation between non-fusion group and control group (P>0.05),while fusion group was significantly increased compared with the other two groups (P<0.001). (2) There was no significant difference in overall lumbar ROM of L2-5 (P> 0.05). CONCLUSION: The individual MALC could restore intervertebral height of lumbar vertebra while maintaining the stability of lumbar vertebra and re-establishing motor function of lumbar space.

Effects of methylprednisolone and treadmill training on spinal cord injury in experimental rats.

Methylprednisolone (MP) is widely used to treat clinical spinal cord injury (SCI). Treadmill training is also considered an important treatment after SCI to improve motor function in patients, resulting in an evident improvement. Therefore, the present study was designed to evaluate and contrast the effects of MP and treadmill training administered in combination or alone after SCI in adult rats. A rat spinal cord T10 contusion model was induced in Sprague-Dawley rats using an impact device. A total of 40 rats were divided into four groups (n=10 rats/group): the MP, MP + treadmill training, SCI and sham group. At 30 min after injury, MP sodium succinate was injected into the rats of the MP and MP + treadmill training groups. Treadmill training began on the second week post-trauma and was performed for 8 weeks. The results showed that MP therapy combined with treadmill training significantly ameliorated several parameters of hind limb function compared with those by MP treatment alone (all P<0.05). A significantly reduced immunopositive area of Nogo receptor and chondroitin sulfate proteoglycans and reduced relative expression of these mRNAs were found in the MP + treadmill training group (P<0.05) compared with the findings in the MP group. In conclusion, the present study indicated that combined MP and treadmill training treatment improved the recovery of hind limb function in rats with SCI, thus potentially representing a promising strategy to cure SCI.

Accuracy and Reliability of Computer-aided Anatomical Measurements for Vertebral Body and Disc Based on Computed Tomography Scans.

OBJECTIVE: To assess whether the computed tomography (CT)-based method of three-dimensional (3D) analysis (Mimics) was accurate and reliable for spine surgical anatomical measurements. METHODS: A total of 40 lumbar segments and 32 inter-vertebral discs from eigth adult male cadavers without fractures or deformities fixed with the classical formaldehyde method were included in this research on 5 June 2017. CT scans including seven dimensions: anterior height of the vertebral body (VBHa), middle height of the vertebral body (VBHm), posterior height of the vertebral body (VBHp), width of the upper endplate (EPWu), depth of the upper endplate (EPDu), anterior height of the inter-vertebral disc in the median sagittal plane (IDHa), and posterior height of the inter-vertebral disc in the median sagittal plane (IDHp). They were performed based on uniform conditions (slice thickness: 0.625 mm) using a CT scanner on 8 June 2017. Afterwards, the surgical anatomical measurements were conducted with a Vernier caliper on 12 June 2017. The computer-aided anatomical measurements were conducted by three investigators using Mimics 16.0 to perform 3D reconstructions of CT bone on 16 June 2017. Finally, the length and angle were measured with associated measurement tools, yielding a verified accuracy of 0.01 mm and 0.01°, respectively. Each measurement was repeated three times, and all anatomical data was analyzed using the statistical software and P-value < 0.05 was considered statistically significant. RESULTS: The results showed no statistically significant difference was observed between the surgical anatomical and computer-aided anatomical measurements (P > 0.05) for lumbar vertebra measurements, and the absolute difference between surgical and computer-aided data were all less than 1.0 mm (for the VBHa, VBHm, VBHp, EPWu, and EPDu were 0.12, 0.03, 0.03, 0.31, and 0.03 mm, respectively). Moreover, although the absolute differences of discs was larger than those of lumbar vertebras, no significant differences were detected between the computer-aided and surgical anatomical measurements for the IDHa, as well as IDHp in the vast majority of measurements (P = 0.543, 0.079 or 0.052 for IDHa, and P = 0.212, 0.133 or 0.042 for IDHp). In addition, excellent reliability correlation was observed between the measurements of each investigator, and the reliability coefficients in the intra-groups were all greater than 0.9 except for IDHp (reliability coefficient = 0.892). Additionally, the reliability coefficients were greater than 0.9 for the all between-group correlations, and a significant correlation was also observed. Furthermore, no statistically significant difference for three anatomical values was found in the computer-assisted measurements of the lumbar bone structure (P > 0.05). Similarly, we did not observe a statistical difference in the anatomical data of the lumbar discs from the three measures (P > 0.05). CONCLUSIONS: Computer-aided anatomical measurement for spine based on CT scans presents the high accuracy and reliability for improving spinal surgical procedures.

ZNF281 Regulates Cell Proliferation, Migration and Invasion in Colorectal Cancer through Wnt/ß-Catenin Signaling.

BACKGROUND/AIMS: Zinc Finger Protein 281 (ZNF281) was recently identified as a novel oncogene in several human carcinomas. However, the clinical significance of ZNF281 in colorectal cancer (CRC) and the molecular mechanisms by which ZNF281 promotes the growth and metastasis of CRC remain unknown. METHODS: ZNF281 expression in CRC tissues was assessed, and the outcomes were analyzed to determine the clinical importance of ZNF281 expression. Cell Transwell assays and a wound healing assay were performed to assess the effects of ZNF281 on CRC cell migration and invasion in vitro. Western blotting was applied to analyze the potential mechanisms. RESULTS: ZNF281 mRNA and protein levels were significantly increased in CRC tissues compared with normal colon tissues, and high ZNF281 expression was associated with advanced T stage, N stage, TNM stage and differentiation. Therefore, ZNF281 expression might be an independent prognostic indicator in CRC patients. Moreover, knockdown of ZNF281 expression suppressed cell proliferation, migration and invasion by inhibiting the Wnt/ß-catenin pathway. CONCLUSION: Our study indicates that ZNF281 plays a critical role in the progression and metastasis of CRC and could represent a potential therapeutic target for CRC.

[CT assisted morphological study of lumbar endplate].

OBJECTIVE: To study and measure the anatomic structure of lumbar vertebral endplate structure in healthy adults by computed tomography(CT) technique in order to provide a useful guidance for the optimal design and clinical application of lumbar prostheses. METHODS: Sixty healthy adults (male and female equals) were recruited for full-waist CT scan after signing the informed consent form in the imaging department of the Second Affiliated Hospital of Xi'an Jiaotong University. The scanning data was imported into the computer aided software Mimics 16.0 for 3D reconstruction and measurement. The acquisition indexes included median sagittal diameter, maximum coronal diameter, concavity depth, median sagittal depression angle, coronal depression angle and so on. Finally, the collected data were statistically analyzed by the statistical software. RESULTS: The median sagittal diameter and the maximum coronal diameter of the upper and lower endplates were not only different between the different sexes(P<0.05), but also were increased with the increase of the lumbar spine sequence. The concavity depth of upper and lower endplates had no gender differences(P>0.05), but had a little change from L1 to L5, fluctuating from 1.5 to 2.0 mm and from 2.2 to 3.9 mm, respectively. In the same sequence, the concavity depth of lower endplate in males was greater than that of upper endplate, and the difference was statistically significant(P<0.05), but there was no significant difference in the concavity depth of upper and lower endplate in females(P>0.05). Sagittal concavity angle and coronal concavity angle of upper and lower endplates changed slightly with the increase of vertebral order, and there was no gender difference in sagittal and coronal concavity angle of most vertebral sequences (P>0.05). Statistics showed that the largest concavity near the caudal lumbar endplate was located on the dorsal side of the endplate plane. CONCLUSIONS: The anatomical structure of the lumbar endplate is very complicated. It is important to master the anatomical parameters of the endplate and make full use of CT before operation for the development and clinical application of the lumbar prosthesis.

[Rapid prototyping navigation template assisted cervical screw implantation:a review].

The cervical screw fixation has been used widely in the clinic setting due to the high fusion rate, immediate fixation of the surgical segment and good correction of the deformity. However, owing to the variation of anatomical structures and the narrow pedicle screws, it's rather difficult to implant the screws through traditional methods. The perforation rate of the screw is high, which can cause serious complications such as neurovascular injury. In recent years, rapid prototyping navigation templates have been reported in the appilication to assist cervical screw placement for improving the accuracy of screw placement. In this paper, we reviewed and summarized published literatures about navigation template assisted cervical screw implantation in the past 20 years, systematically introduced the methods of producing and using of navigation templates, the development of design concept and the status of application in cervical spine surgery. To date, relevant clinical and cadaveric studies confirm that the use of rapid prototyping navigation template assisted cervical screw placement in cervical surgery can reduce screw perforation rate, intraoperative ionizing radiation injury and operation time, which is worth applying in the clinical practice. However, specific clinical effects of different design types of navigation templates are not well summarized. As a result, more clinical and cadaveric studies comparing the accuracy and safety of navigation templates of different design types are needed to help clinicians select the appropriate navigation template for surgery.

[CT assisted goat lumbar vertebrae anatomical measurement and comparison with human lumbar vertebrae].

OBJECTIVE: To study the anatomical measurement of goat lumbar vertebrae and to compare with human lumbar vertebrae, so as to build the foundation for establishing animal models of lumbar prosthesis. METHODS: The anatomical parameters of the vertebral body, pedicle and intervertebral disc in the fresh lumbar vertebrae of Boer goat and the lumbar vertebrae of healthy adults were collected by computer aided software Mimics16.0, and the anatomical characteristics of the two lumbar vertebrae were compared with the statistical software. RESULTS: The anterior vertebral body height(VBHa) of goat lumbar was less than the middle vertebral body height(VBHm), which was less than the posterior vertebral body height(VBHp), and the maximum values were (38.7±2.9), (40.1±2.6) and (40.7±2.7) mm respectively. Its endplate width was greater than its depth, with the whole shaped like a heart or a kidney. The cranial endplate of goats was convex while the caudal endplate was depressed and the depression was small, with a maximum value of (1.6±0.6) mm. The pedicle height of goats increased from L11 to L̀ with the maximum of (30.5±1.9) mm; its pedicle width and angle increased firstly and then decreased with the increase of vertebra level and the minimum values were (6.7±0.4) mm and(45.9±2.6)° respectively. The anterior intervertebral disc height was larger than the middle which was larger than the posterior and all varied slightly with the changes of intervertebral spaces; the height and width of intervertebral foramen separately waved at (12.9±0.3) to (14.3±1.0) mm and (5.7±1.0) to (6.7±0.9) mm. The comparative results showed that the vertebral body height, pedicle height and angle of goats were greater than those of humans (P<0.05) while the width and depth of the endplate, the intervertebral disc height, and etc. were significantly smaller than those of humans (P<0.05). In addition, some structures, such as the height of pedicle and intervertebral disc, also showed different changing laws with the increase of vertebra level. CONCLUSIONS: Although there are similarities in goat lumbar spine in some aspects, such as endplate and foramen foramen, there are still many differences in many aspects. Understanding the anatomical characteristics of goat lumbar vertebrae and the difference between goat and human is of great guiding significance for the research of goat prosthesis and related technology.

[Eestablishment of the model of goat lumbar spinal fusion by 3D printing technology and experimental perioperative management].

OBJECTIVE: To explore the feasibility and the attention of perioperative management of goat lumbar fusion model for individualized 3D printing technology. METHODS: According to preoperative X-ray and CT three dimensional reconstruction data of 10 males Boer goat's lumbar(1-2 years old, weight 35-45 kg), the preoperative open height were determined, meanwhile, according to the theoretical entry point of nails, the length of steel plate, arc, and setting position, screw length for reference were determined, the lumbar lateral anterior plate was designed and 3D-printed. Goats lied on the right side, under the general anesthesia, the lumbar vertebrae of the goats and the adjacent intervertebral disc were resected, and the titanium cage after the bone graft was implanted into the goat, the 3D-print lateral bone plate was fixed. After operation, feeding, fluid infusion, anti infection, postoperative complications management, respiratory digestion perioperative management were performed. RESULTS: The 10 models for goats were successful in results. Postoperative X-ray film and three-dimensional reconstruction of CT showed that titanium cage and bone plate were in good position and reliable. Three months after the operation, CT 3D reconstruction and micro-CT of the goat were observed, and the fusion of the spine was observed. Imaging studies showed that the fusion of the lateral bone plate fixation titanium cage was both at the end of the titanium cage and the dense bone trabecular formation between the vertebral bodies. CONCLUSIONS: The 3D printing technology sets up the goat lumbar spinal fusion model successfully, which is a kind of effective, more successful, reliable and stable method, perioperative management. The method is scientific, practical, and more humanized, to ensure that lumbar lateral successfully implanted the nail plate of lateralanterior internal fixation system, with reduction of occurrence of surgical complications.

Ebselen protects mitochondrial function and oxidative stress while inhibiting the mitochondrial apoptosis pathway after acute spinal cord injury.

Ebselen is a fat-soluble small molecule and organic selenium compound that regulates the activity of glutathione peroxidase to alleviate mitochondrial oxidative stress and improve mitochondrial function. In the present study, we aimed to investigate the effects of ebselen on mitochondrial oxidative stress response, mitochondrial apotosis, and motor behaviors after spinal cord injury (SCI). We found that ebselen significantly increased the BBB score in motor behavior, thus suggesting a rescue effect of ebselen on motor function after SCI in rats. Meanwhile, we revealed that ebselen can increase glutathione (GSH) content as well as superoxide dismutase (SOD) and catalase (CAT) activities after SCI-this suggests ebselen has an antioxidant effect. Furthermore, the ATP content and Na+-K+-ATPase activity in mitochondria were increased by ebselen after SCI, while the mitochondrial membrane potential (MMP) was decreased by ebselen. The Cytochrome C and Smac release from mitochondria were reduced by ebselen after SCI, thus indicating improved membrane permeability by ebselen. Moreover, the alterations in caspase-3, Bax and Bcl-2 protein expression, as well as the proportion of cell apoptosis were improved by ebselen treatment, which together suggested that ebselen has an inhibitory effect on mitochondrial apotosis pathways after SCI. Taken together, our results suggest that ebselen can inhibit secondary damage caused by spinal cord injury. Indeed it plays a neuroprotective role in spinal cord injury perhaps by improving mitochondrial function and inhibiting the mitochondrial apoptosis pathway.

[Clinical effects of high frequency repeated transcranial magnetic stimulation therapy on dyskinesia in patients with incomplete spinal cord injury:a Meta-analysis].

OBJECTIVE: To systematically evaluate the clinical effect of high frequency repeated transcranial magnetic stimulation(HF rTMS)therapy on dyskinesia in patients with incomplete spinal cord injury. METHODS: Randomized controlled trials(RCTs) about HF rTMS therapy on patients with motor incomplete spinal cord injury were searched electronically in PubMed, Google scholar, Cochrane library, Clinical trial, Medline, Web of science, CNKI, VIP, and Wanfang database before October 2016. Two reviewers independently screened the literatures according to the inclusion and exclusion criteria, as well as extracted the data and assessed the methodological quality. The observed outcomes included ASIA motor score, ASIA lower extremities motor score(LEMS), Modified Ashworth score (MAS), Ten-meter walking test (10MWT) and Walking index for SCI II(WISCI II), and the outcomes were analyzed using RevMan5.2 software provided by the Cochrane information management system. RESULTS: Five RCTs involved 103 patients were included, and 61 patients(experimental group) accepted real rTMS and physical rehabilitation care for SCI, 51 patients(control group) accepted only physical rehabilitation care. There were significant differences in ASIA motor score, LEMS and 10MWT between two groups after HF rTMS therapy (statistics were Z=2.96, P=0.003; Z=3.04, P=0.002; Z=2.16, P=0.03; respectively). When stimulating the leg motor cortex, there was significant difference in MAS between two groups(Z=2.79, P=0.005), and when stimulating the vertex, there was no significant difference(Z=0.09, P=0.93). There was no significant difference in WISCI IIscore after HF rTMS therapy between two groups(Z=0.90, P=0.37). CONCLUSIONS: HF rTMS can raise motor score in patients with incomplete spinal cord injury, improve the spasticity of the lower extremities, and increase the motor ability.

Methotrexate combined with methylprednisolone for the recovery of motor function and differential gene expression in rats with spinal cord injury.

Methylprednisolone is a commonly used drug for the treatment of spinal cord injury, but high doses of methylprednisolone can increase the incidence of infectious diseases. Methotrexate has anti-inflammatory activity and immunosuppressive effects, and can reduce inflammation after spinal cord injury. To analyze gene expression changes and the molecular mechanism of methotrexate combined with methylprednisolone in the treatment of spinal cord injury, a rat model of spinal cord contusion was prepared using the PinPoint™ precision cortical impactor technique. Rats were injected with methylprednisolone 30 mg/kg 30 minutes after injury, and then subcutaneously injected with 0.3 mg/kg methotrexate 1 day after injury, once a day, for 2 weeks. TreadScan gait analysis found that at 4 and 8 weeks after injury, methotrexate combined with methylprednisolone significantly improved hind limb swing time, stride time, minimum longitudinal deviation, instant speed, footprint area and regularity index. Solexa high-throughput sequencing was used to analyze differential gene expression. Compared with methylprednisolone alone, differential expression of 316 genes was detected in injured spinal cord treated with methotrexate and methylprednisolone. The 275 up-regulated genes were mainly related to nerve recovery, anti-oxidative, anti-inflammatory and anti-apoptotic functions, while 41 down-regulated genes were mainly related to proinflammatory and pro-apoptotic functions. These results indicate that methotrexate combined with methylprednisolone exhibited better effects on inhibiting the activity of inflammatory cytokines and enhancing antioxidant and anti-apoptotic effects and thereby produced stronger neuroprotective effects than methotrexate alone. The 316 differentially expressed genes play an important role in the above processes.

[Development and application of artificial vertebral body].

Artificial vertebral body has achieved good results in treating spinal tumors, tuberculosis, fracture and other diseases. Currently, artificial vertebral body with variety of kinds and pros and cons, is generally divided into two types: fusion type and movable type. The former according to whether the height could be adjusted and strength of self-stability is divided into three types: support-fixed type, adjust-fixed type and self-fixed type. Whether the height of self-fixed type could be adjusted is dependent on structure of collar thread rotation. The latter is due to mobile device of ball-and-socket joints or hollow structures instead of the disc which retains the activity of the spine to some extent. Materials of artificial vertebral body include metals, ceramics, biomaterials, polymer composites and other materials. Titanium with a dominant role in the metal has developed to the third generation, but there are still defects such as poor surface bioactivity; ceramics with the representative of hydroxyapatite composite, magnetic bioceramics, polycrystalline alumina ceramics and so on, which have the defects of processing complex and uneven mechanical properties; biological material is mainly dominated by xenogeneic bone, which is closest to human bone in structure and properties, but has defects of low toughness and complex production; polymer composites according to biological characteristics in general consists of biodegradable type and non-biodegradable type which are respectively represented by poly-lactide and polyethylene, each with advantages and disadvantages. Although the design and materials of prosthesis have made great progress, it is difficult to fully meet requirements of spinal implants and they need be further optimized. 3D printing technology makes process of the complex structure of prosthesis and individual customization possible and has broad development prospects. However, long production cycles and high cost of defect should be overcome. Although artificial vertebral body has achieved curative effect in treating spinal disease, there were reports of implant loosening or displacement. Combining with evaluation standards not unified, short follow-up time, its exact effect needs further observation.

[Effects of different nitrogen regulators on nitrogen transformation in different soil types].

Laboratory incubation experiments were conducted to compare the inhibitory effects of dicyandiamide (DCD) and 3,5-dimethylpyrazole (DMP) on nitrification in meadow-cinnamon soil and fluvo-aquic soil, the main soil types of North China Plain. The synergistic effect of DMP combined with urease inhibitor hydroquinone (HQ) on nitrogen transformation in fluvo-aquic soil was further studied. The results indicated that, in contrast to DCD, DMP had a stronger inhibitory effect on the nitrification in the two tested soils. In comparison with the treatment without any inhibitor, the soil NH(4+)-N content in the treatment with DMP increased significantly by 149.5%-387.2% at the peak of nitrogen transformation stage, and the soil NO(3-)-N content reduced by 22.3%-55.3%. The inhibitory effects of DCD and DMP in fluvo-aquic soil were both stronger than in meadow-cinnamon soil. In addition, the application of DMP combined with HQ had a significantly synergistic effect on soil nitrogen transformation.

[Effects of nitrogen regulators on fertilizer nitrogen transformation in meadow cinnamon soil and on pakchoi growth].

Soil incubation test and pot experiment were conducted to investigate the effects of dicyandiamide (DCD) and its combination with nano-carbon on the transformation of fertilizers (urea and ammonium bicarbonate) nitrogen (N) in meadow cinnamon soil, a typical soil type in North China Plain, and on the growth of pakchoi (Brassica chinensis). In the first two weeks after applying urea and ammonium bicarbonate, the soil NH4+-N and NO3(-)-N contents varied greatly, but little variation was observed since then. The effects of the applied fertilizer N on the pakchoi growth and its N use efficiency differed significantly at early growth stages, but had little difference at harvesting stage. The DCD inhibited the transformation of the fertilizer N (especially ammonium bicarbonate N) into nitrate markedly, and this effect increased with increasing DCD dose. Under the conditions of our experiment, the optimal application rate of DCD was 1.0-1.5% of applied fertilize N, which could increase the pakchoi yield significantly, improve the leaf color, decrease the plant nitrate contents, and increase the fertilizer N use efficiency. The combination of DCD and nano-carbon exerted a synergistic effect on inhibiting soil ammonium oxidation, and also, promoted the pakchoi growth and N utilization at early growth stages significantly and decreased the plant nitrate level at harvesting stage.

Over-expression of atf4 in Xenopus embryos interferes with neurogenesis and eye formation.

Accumulated evidence indicates that the activating transcription factor 4 (atf4) is a developmentally relevant gene. Here, we report on the characterization of atf4 in Xenopus embryos, which is differentially expressed in the central nervous system, eyes, blood, and the pronephros, as well as in developing endodermal organs such as the stomach, duodenum, liver, and pancreas. Ectopic expression of atf4 in the animal hemisphere of Xenopus embryos had no obvious effects on the induction of neural progenitors, but suppressed neurogenesis and eye formation without promoting apoptosis. Our data suggest that tightly controlled atf4 activities may be crucial for normal neurogenesis and early eye patterning.