BACKGROUND:Bone tissue loss caused by tumors and trauma can have an adverse effect on postoperative rehabilitation.Therefore,scaffold materials are usually implanted during treatment.However,the existing implant materials are relatively simple and lack antibacterial properties.Early implantation may lead to iatrogenic autoinfection and have an adverse effect on osteogenesis.OBJECTIVE:To construct a KR-12-a5 polypeptide-nanohydroxyapatite-small intestinal submucosa composite scaffold and evaluate its feasibility as a material for promoting bone defect repair.METHODS:The small intestinal submucosa scaffold and the small intestinal submucosa scaffold containing 25,50,and 100 mg/mL nanohydroxyapatite(referred to as nHA-SIS scaffold)were prepared by 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride/N-hydroxysuccinimide cross-linking method.The appropriate scaffold was screened for subsequent experiments by mechanical property testing.The antibacterial properties of KR-12-a5 polypeptide solution against Staphylococcus aureus,Streptococcus gordonii,and Fusobacterium nucleatum were detected.The nHA-SIS scaffolds were immersed in 250,500,and 1 000 μg/mL KR-12-a5 peptide solutions for 24 hours,and then freeze-dried to obtain peptide-loaded nanohydroxyapatite-porcine small intestinal submucosa composite scaffolds(denoted as P-nHA-SIS scaffolds).The sustained-release properties of the three groups of scaffolds were characterized.The nHA-SIS scaffolds and the three groups of P-nHA-SIS scaffolds were co-cultured with Staphylococcus aureus,Streptococcus gordonii,and Fusobacterium nucleatum for 24 hours or 48 hours.The scaffolds with strong antibacterial ability were screened by live and dead bacteria staining and scanning electron microscopy for subsequent experiments.The degradation properties and water absorption rates of the uncross-linked small intestinal submucosa scaffolds,cross-linked small intestinal submucosa scaffolds,nHA-SIS scaffolds,and P-nHA-SIS scaffolds were characterized.The extracts of cross-linked small intestinal submucosal scaffolds,nHA-SIS scaffolds,and P-nHA-SIS scaffolds were co-cultured with MC3T3-E1 cells.CCK-8 assay and live-dead cell staining were performed.The effects of the extracts of the three scaffolds on the migration of MC3T3-E1 cells were detected by Transwell chamber assay.RESULTS AND CONCLUSION:(1)The elastic modulus and compressive strength of 25,50,and 100 mg/mL nHA-SIS scaffolds were higher than those of small intestinal submucosal scaffolds(P＜0.05),among which the elastic modulus and compressive strength of 25 mg/mL nHA-SIS scaffolds were the highest,and this group of scaffolds were selected for subsequent experiments to load peptides.(2)KR-12-a5 peptide had strong antibacterial activity against common bacteria in bone defects(Staphylococcus aureus,Streptococcus gordonii,and Fusobacterium nucleatum).The three groups of P-nHA-SIS scaffolds all had sustained release properties.With the increase of peptide mass concentration,the antibacterial property of P-nHA-SIS scaffold was enhanced.Among them,the P-nHA-SIS scaffold loaded with 500 μg/mL peptide had achieved a satisfactory antibacterial effect,and this group of scaffolds would be selected in the future.(3)The degradation rate of the three groups of cross-linked scaffolds was lower than that of the uncross-linked scaffolds,and the water absorption rate was greater than that of the uncross-linked scaffolds.P-nHA-SIS scaffolds could promote the proliferation and migration of MC3T3-E1 cells without affecting the activity of MC3T3-E1 cells.(4)The results show that P-nHA-SIS scaffolds have strong antibacterial properties and the ability to promote the proliferation and migration of MC3T3-E1 cells,and are expected to be used in bone defect repair.

BACKGROUND:Bone tissue loss caused by tumors and trauma can have an adverse effect on postoperative rehabilitation.Therefore,scaffold materials are usually implanted during treatment.However,the existing implant materials are relatively simple and lack antibacterial properties.Early implantation may lead to iatrogenic autoinfection and have an adverse effect on osteogenesis.OBJECTIVE:To construct a KR-12-a5 polypeptide-nanohydroxyapatite-small intestinal submucosa composite scaffold and evaluate its feasibility as a material for promoting bone defect repair.METHODS:The small intestinal submucosa scaffold and the small intestinal submucosa scaffold containing 25,50,and 100 mg/mL nanohydroxyapatite(referred to as nHA-SIS scaffold)were prepared by 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride/N-hydroxysuccinimide cross-linking method.The appropriate scaffold was screened for subsequent experiments by mechanical property testing.The antibacterial properties of KR-12-a5 polypeptide solution against Staphylococcus aureus,Streptococcus gordonii,and Fusobacterium nucleatum were detected.The nHA-SIS scaffolds were immersed in 250,500,and 1 000 μg/mL KR-12-a5 peptide solutions for 24 hours,and then freeze-dried to obtain peptide-loaded nanohydroxyapatite-porcine small intestinal submucosa composite scaffolds(denoted as P-nHA-SIS scaffolds).The sustained-release properties of the three groups of scaffolds were characterized.The nHA-SIS scaffolds and the three groups of P-nHA-SIS scaffolds were co-cultured with Staphylococcus aureus,Streptococcus gordonii,and Fusobacterium nucleatum for 24 hours or 48 hours.The scaffolds with strong antibacterial ability were screened by live and dead bacteria staining and scanning electron microscopy for subsequent experiments.The degradation properties and water absorption rates of the uncross-linked small intestinal submucosa scaffolds,cross-linked small intestinal submucosa scaffolds,nHA-SIS scaffolds,and P-nHA-SIS scaffolds were characterized.The extracts of cross-linked small intestinal submucosal scaffolds,nHA-SIS scaffolds,and P-nHA-SIS scaffolds were co-cultured with MC3T3-E1 cells.CCK-8 assay and live-dead cell staining were performed.The effects of the extracts of the three scaffolds on the migration of MC3T3-E1 cells were detected by Transwell chamber assay.RESULTS AND CONCLUSION:(1)The elastic modulus and compressive strength of 25,50,and 100 mg/mL nHA-SIS scaffolds were higher than those of small intestinal submucosal scaffolds(P＜0.05),among which the elastic modulus and compressive strength of 25 mg/mL nHA-SIS scaffolds were the highest,and this group of scaffolds were selected for subsequent experiments to load peptides.(2)KR-12-a5 peptide had strong antibacterial activity against common bacteria in bone defects(Staphylococcus aureus,Streptococcus gordonii,and Fusobacterium nucleatum).The three groups of P-nHA-SIS scaffolds all had sustained release properties.With the increase of peptide mass concentration,the antibacterial property of P-nHA-SIS scaffold was enhanced.Among them,the P-nHA-SIS scaffold loaded with 500 μg/mL peptide had achieved a satisfactory antibacterial effect,and this group of scaffolds would be selected in the future.(3)The degradation rate of the three groups of cross-linked scaffolds was lower than that of the uncross-linked scaffolds,and the water absorption rate was greater than that of the uncross-linked scaffolds.P-nHA-SIS scaffolds could promote the proliferation and migration of MC3T3-E1 cells without affecting the activity of MC3T3-E1 cells.(4)The results show that P-nHA-SIS scaffolds have strong antibacterial properties and the ability to promote the proliferation and migration of MC3T3-E1 cells,and are expected to be used in bone defect repair.

Occipitocervical fusion (OCF) is used to treat the instability of the cranio-cervical junction due to various reasons (such as trauma, rheumatoid arthritis, infection, tumor, congenital malformations and degeneration). A satisfactory fusion rate can be obtained and the stability of the occipital neck can be reconstructed by OCF. Dysphagia is one of the most common complications after OCF, which seriously affects the quality of life of patients after surgery. This article mainly focuses on the evaluation and prediction methods of dysphagia after OCF, and summarizes related research in the past 16 years, and provides guidance and direction for how to predict the occurrence of dysphagia during OCF and the evaluation of postoperative dysphagia. The evaluation of dysphagia is mainly conducted using the Bazaz dysphagia score, swallowing quality of life scale (SWAL-QOL) and eating assessment tool-10 (EAT-10) score. However, the clinical prediction of dysphagia is mainly based on the changes of cervical curvature parameters (O-C 2 angle, O-EA angle, Oc-Ax angle, PI angle). At present, there are many methods for clinical evaluation and prediction of dysphagia, but the best evaluation method is still uncertain. We reviews the evaluation and prediction methods of postoperative dysphagia of OCF, showing that the Bazaz dysphagia score, SWAL-QOL score and EAT-10 score scale are suitable for evaluating postoperative dysphagia of OCF. During OCF operation, adjustment of O-C 2 Angle >-5°, O-EA Angle >100°, Oc-Ax Angle >65°, and increase of postoperative PI Angle from preoperative PI Angle (that is, dPI Angle) ≥0° can reduce the probability of dysphagia to a certain extent.

Objectives:To introduce the definition of the spinal cord(SC)line,and its clinical classification and application strategies in posterior cervical open-door laminoplasty,and to examine and analyze the credibility and repeatability of this classification.Methods:The clinical data of a total of 86 patients who underwent cervical open-door laminoplasty via posterior approach in The Second Affiliated Hospital of Wen-zhou Medical University from January 2018 to December 2020 were analyzed retrospectively.There were 51 males and 35 females,aged 34-77 years old,with postoperative follow-up period ranging from 12 to 36 months.The patients were classified into three types based on the location relationships between the SC line and compressor in the preoperative MRI:Type Ⅰ,the compressor at compression level did not exceed the SC line;Type Ⅱ,the compressor contacted the SC line;Type Ⅲ,the compressor exceeded the SC line.Five spinal surgeons independently evaluated and classified the MRI images of the patients,and Kappa consistency tests were performed to analyze the credibility and repeatability.50 patients with multilevelcervical spinal cord compression diseases(cervical spondylotic myelopathy,ossification of the posterior longitudinal ligament,and developmental cervical spinal canal stenosis)were recruited and treated for a prospective study from January 2021 to December 2022,and the range of open-door segments was determined under the principle of improv-ing the SC line classification as much as possible.The patients were followed up for 12 to 34 months.The modified anterior spinal cord compression score,neck pain visual analogue scale(VAS),Japanese Orthopaedic Association(JOA)score and recovery rates of the patients were recorded pre-operatively and at final follow-up in both retrospective and prospective studies.Paired samples t test was used to compare the scores before and after surgery in each type of patients,and one-way ANOVA was used to compare the scores between the three groups,to assess the postoperative spinal cord decompression and clinical outcomes of the different SC line types.Results:Among the 86 patients analyzed retrospectively,38 were Type Ⅰ,31 were Type Ⅱand 17 were Type Ⅲ.The Kappa coefficient was 0.817-0.945 for inter-observer consistency,which was 0.891-0.963 for intra-observer consistency,indicating satisfactory credibility and repeatability.There was no significant difference in modified anterior spinal cord compression score and VAS score between the three types of patients before surgery(P＞0.05),and all of them were statistically different at the final follow-up compared with the preoperative period(P＜0.05).The modified anterior spinal cord compression score and VAS score were the lowest at the final follow-up in Type Ⅰ,which were the highest in Type Ⅲ(P＜0.05).The JOA recovery rate was(73.49±11.26)％in Type Ⅰ,(67.08±9.01)％in Type Ⅱ,and(53.74±7.93)％in TypeⅢ,with statistically significant differences between the three types(P＜0.05).Among the 50 patients analyzed prospectively,27 were Type Ⅰ,15 were Type Ⅱ and 8 were Type Ⅲ.The preoperative spinal cord com-pression score was 3.67±0.47 in Type Ⅰ,3.84±0.37 in Type Ⅱ,and 4.00±0.00 in Type Ⅲ,which was 1.24±0.62 in Type Ⅰ,2.60±0.58 in Type Ⅱ,and 3.40±0.52 in Type Ⅲ at the final follow-up,respectively.The VAS score decreased from 6.48±0.85 preoperatively to 1.11±0.51 at final follow-up in Type Ⅰ.Type Ⅱcases exhibited a decrease in VAS score from 6.67±0.90 preoperatively to 1.73±0.59 at final follow-up.And the VAS score decreased from a preoperative value of 7.13±0.64 to 2.38±0.52 at final follow-up in Type Ⅲ(P＜0.05).The modified anterior spinal cord compression score and VAS score were the lowest in Type Ⅰand the highest in Type Ⅲ at final follow-up(P＜0.05).The JOA score improved from 12.07±1.17 preopera-tively to 15.59±0.69 at final follow-up in Type Ⅰ.Type Ⅱ cases exhibited an improvement in JOA score from 10.93±0.80 preoperatively to 14.67±0.72 at final follow-up.And the JOA score improved from a preop-erative value of 10.13±1.13 to 13.63±0.74 at final follow-up in Type Ⅲ(P＜0.05).The JOA recovery rate was(72.50±12.38)％in Type Ⅰ,(61.99±9.78)％in Type Ⅱ,and(51.25±5.19)％in Type Ⅲ,which was statisti-cally different between the three groups(P＜0.05).Conclusions:The SC line and its classification are practical and reliable,demonstrating good credibility and repeatability.Suitable open-door segment in posterior open-door laminoplasty in patients of Type Ⅰ SC line can make anterior spinal cord compression relieved;And anterior surgery needs to be considered when anterior compression remained after posterior surgery in patients of Type Ⅲ SC line.

Objective To observe the tumorigenicity of High Five insect cell line in Balb/c nude mice,and make sure the safety of the cells when used in vaccine production.Methods Balb/c nude mice were randomly divided into 5 groups:the basic cell bank of High Five group,the highest limited passages of High Five group,HEp-2 cell group as positive control,CEF cell group as negative control,and blank control.Except of the blank control,cell suspension was injected subcutaneously into the nude mice in the different groups,respectively.At 3 and 12 weeks after injection,anatomical observation and histopathologic examination were performed to detect the tumor formation.Results At 3 and 12 weeks after injection,the tumorigenicity study results showed that no tumor developed at the transplantation site in the blank control group,negative group,and High Five groups.Histopathological examinations also showed no abnormality in these groups.Otherwise,squamous cell carcinoma was developed in the positive group at 3 weeks after injection.Conclusions High Five cells of basic cell bank and highest limited passages are not tumorigenic,and can be used in vaccine production safely.