Objective: To establish a method for determining the molecular weight and molecular weight distribution of Poly(Lactide-co-Glycolide Acid) (PLGA) using Size Exclusion Chromatography-Refractive Index-Multiangle Laser Light Scattering (SEC-RI-MALLS) and Size Exclusion Chromatography-Refractive Index (SEC-RID), and to compare the results obtained from these two methods.
Methods: For SEC-RI-MALLS, tetrahydrofuran was used as the mobile phase, Shodex GPC KF-803L was employed as the chromatographic column with a flow rate of 1 mL·min^-1, column temperature at 30 ℃, and an injection volume of 100 μL. For SEC-RID, tetrahydrofuran was also used as the mobile phase, Agilent PLgel 5 μm MIXD-D was used as the chromatographic column with a flow rate of 1 mL·min^-1, column temperature at 30 ℃, differential detector temperature at 35 ℃, and an injection volume of 20 μL. The molecular weight and molecular weight distribution were calculated using Agilent’s GPC software. The newly established methods were validated methodologically, and the molecular weight and molecular weight distribution of 13 batches of samples were determined.
Results: The precision, accuracy, stability, and repeatability tests for SEC-RI-MALLS showed RSD values of 1.35%, 1.58%, 1.53%, and 1.26%, respectively. The SEC-RID method exhibited good linearity (r=0.999 9), with RSD values for precision, accuracy, stability, and repeatability tests (n=6) of 2.05%, 1.62%, 1.30%, and 2.97%, respectively. The results obtained from SEC-RI-MALLS were lower than those from SEC-RID, and the molecular weight distribution coefficient was smaller, but the results from the paired T-test performed with the value measured by SEC-RID method and the value measured by SEC-RI-MALLS method multiplied a conversion coefficient of 1.5 showed no significant difference between the two methods.
Conclusion: Both methods are stable and reliable, and can be used for the determination of PLGA molecular weight and molecular weight distribution based on the specific situations.

OBJECTIVE To construct an evaluation index system for the core competencies of ethics committee members of drug clinical trial institution， providing a basis for optimizing the training system for committee members， improving the quality of ethical review， and fully safeguarding the safety and rights of subjects. METHODS Using methods such as literature research and expert consultation， a preliminary core competency evaluation index system was constructed. The Delphi method was employed to revise and validate it， ultimately forming an evaluation index system for the core competencies of ethics committee members. Based on this system， a questionnaire survey was conducted among 90 ethics committee members from 29 drug clinical trial institutions nationwide， comparing their importance rating and self-assessment scores of the core competency indexes. RESULTS The evaluation system constructed included 4 primary indicators （ethics and professional knowledge， ethics review ability， communication and expression ability， moral integrity and work style） and 39 secondary indicators （familiarity with the content of clinical trial-related laws and regulations， ability to complete project ethics review and identify ethical defects in research protocols within a short period of time， ability to judge the scientific value of clinical research， etc.）. The results of questionnaire survey showed that the interviewed ethics committee members had significant capability gaps in dimensions such as regulatory knowledge， ethical norms， review efficiency， risk judgment， and problem analysis. The differences between the importance rating scores of corresponding secondary indicators and the self-assessment scores were all no less than 0.38. CONCLUSIONS This study has developed a quantifiable and stratified core competency assessment tool for ethics committee members. It can provide a scientific framework for committee member training， qualification certification， and standardized management of ethics committees.

BACKGROUND:The problem of intervertebral disc injury and degeneration has been studied in many ways.Many studies have shown that intervertebral disc injury and degeneration is driven by mechanical loading factors.However,the potential relationship between common phenotypes of intervertebral disc injury and degeneration and mechanical loading factors has been rarely summarized. OBJECTIVE:To summarize the types of common structural abnormalities exhibited by intervertebral disc injury and degeneration in the published literature,and sum up the potential links to the types of mechanical loading that lead to these structural abnormalities in in vitro and ex vivo experimental studies. METHODS:Using the terms"intervertebral disc failure,intervertebral disc injury,mechanical load,mechanical factor,load factor,biomechanics"as Chinese and English key words in PubMed,CNKI,and WanFang databases,articles related to intervertebral disc injury degeneration and mechanical load factors were retrieved.Literature screening was performed according to the inclusion and exclusion criteria,and 88 articles were finally included. RESULTS AND CONCLUSION:(1)Common structural abnormalities of intervertebral discs include decreased intervertebral disc height,disc bulge,osteophyte formation,annulus fibrosus tear,intervertebral disc herniation or disc prolapse,endplate damage,Schmorl nodes and intervertebral disc calcification.Intervertebral discs are susceptible to mechanical load types such as compression,bending,axial rotation,and compound loads.(2)The compressive load mainly causes the decrease of the proteoglycan content and the water-binding ability of the intervertebral disc,leading to the decrease or swelling of the intervertebral disc and further damage and degeneration of the intervertebral disc.In addition,the excessive compressive load causes greater damage to the endplate.(3)Bending load and axial rotation load damage the annulus fibrosus more than the endplate,and prolonged or repeated bending loads can cause tearing of the fibrous annulus and herniation or prolapse of the intervertebral disc,while pure axial rotation loads can induce less damage to the intervertebral disc and only cause the tear of the annulus fibrosus.(4)However,when different load types act in combination,it is more likely to result in high stress on the disc and a greater risk of disc injury.(5)Injury and degeneration of the intervertebral disc present progressive structural damage,and early prevention and protection are particularly important in clinical practice.Future tissue engineering research can start with early repair of the intervertebral disc.

BACKGROUND:Exosomes play a role in all stages of wound repair,and there is currently a large body of research on exosomes in skin wound repair,which has been shown to have great potential for clinical applications. OBJECTIVE:To summarize and discuss the main mechanisms and clinical applications of exosomes in the treatment of skin wounds,in order to promote the clinical translation of exosomes. METHODS:PubMed,clinicaltrials.gov,China National Knowledge Infrastructure,Food and Drug Administration database,and Chinese Clinical Trial Register were searched from inception to March 2023.The English search terms were"exosomes,wound healing,stem cells,chronic wound,immunoregulation,inflammation,skin,therapeutic use,isolation,characterization,infections".The Chinese search terms were"exosomes,wound healing,stem cells,immunomodulation,clinical applications".A total of 79 articles were included for the summary. RESULTS AND CONCLUSION:(1)Exosomes can improve and accelerate wound healing through inflammation regulation,immune protection,angiogenesis,cell proliferation and migration,and collagen remodeling.(2)Exosomes derived from stem cells have mature preparation techniques and related mechanism research,which is currently the mainstream research direction.Non-stem cell-derived exosomes have the advantages of convenience,economy,and easy production,and can be used as a supplement for clinical applications.(3)The clinical application of exosomes is still in its infancy,but has great potential for application.Various exosome modification techniques have laid the foundation for the future development of clinically personalized services and require further research.(4)The clinical translation of exosomes faces many challenges,such as low yield,high heterogeneity,lack of unified standards for isolation,purification,and quality control,and difficulties in storage.

BACKGROUND:Vibration environment can cause spinal injury,especially in patients with scoliosis.At present,there is no information about the inherent mode of the whole spine from T1 to the pelvis in scoliosis patients in the free state. OBJECTIVE:To analyze the dynamic characteristics of the whole spine in patients with scoliosis by the finite element method. METHODS:Based on CT scan images,a three-dimensional finite element model of the T1-pelvic total spine of an 11-year-old patient with thoracolumbar biflexion scoliosis was established,and the Cobb angles of thoracolumbar scoliosis were 36° and 24°,respectively.The mode analysis in the free state of the whole spine was carried out by the finite element method. RESULTS AND CONCLUSION:The fifteen-order free modes of the spine were extracted,and the dynamic characteristics of the scolio-curved spine were obtained.The resonance frequency distribution of the spine was concentrated.The thoracic vertebra was the most deformed in the whole spine model,and the amplitude of the thoracic vertebra was larger than that of the lumbar vertebra.Modal analysis was used to analyze the vibration characteristics of scoliosis patients in the vibration environment.It is of great significance to determine the natural frequency,vibration mode,and amplitude of scoliosis patients for analyzing the vibration characteristics of scoliosis.

BACKGROUND:Osteoporosis vertebral compression fracture is a common fracture secondary to osteoporosis,and there is currently a lack of effective predictive indicators and methods for osteoporosis vertebral compression fracture. OBJECTIVE:To investigate the predictive effects of paravertebral muscle degeneration,functional cross-sectional area,and percentage of fat infiltration on osteoporotic vertebral compression fractures. METHODS:The 224 patients with osteoporosis diagnosed from January 2018 to June 2022 were included.They were followed up for more than 2 years.They were divided into fracture group and non-fracture group according to the presence and absence of vertebral fracture.The detailed information of demographics,body mass index,bone mineral density and so on were collected.The functional cross-sectional area and percentage of fat infiltration of bilateral Psoas major muscle and extensor dorsi(Erector spinae muscles muscle and multifidus muscle)at the level of lower endplate of L2 vertebral body were measured and calculated. RESULTS AND CONCLUSION:(1)224 patients were ultimately included,of which 126 had fractures as the fracture group and 98 had no fractures as the non-fracture group.There was no statistically significant difference in age,gender,height,body mass,body mass index,and fracture segment between the two groups(P>0.05).(2)The bone mineral density of the fracture group was significantly lower than that of the non-fracture group(P<0.05).Functional cross-sectional areas of Psoas major muscle and extensor dorsi in the fracture group were significantly lower than those in the non-fracture group(P<0.05).The percentage of fat infiltration of the extensor dorsi in the fracture group was significantly higher than that in the non-fracture group(P<0.05).There was no significant difference in percentage of fat infiltration of Psoas major muscle between the two groups(P>0.05).(3)Receiver operating characteristic analysis showed that the vertebral bone mineral density,percentage of fat infiltration of extensor dorsi,functional cross-sectional area of extensor dorsi and percentage of fat infiltration of Psoas major muscle were 0.903 g/cm2,35.426%,418.875 mm2,and 6.375%,respectively.The areas under curve were 0.634,0.755,0.876,and 0.585,respectively.(4)These findings indicate that paravertebral muscle degeneration is strongly associated with the occurrence of osteoporotic vertebral compression fractures.The functional cross-sectional area of extensor dorsi muscle can effectively predict the occurrence of osteoporotic vertebral compression fractures,which is helpful for early prevention and treatment of osteoporotic vertebral compression fractures.

Objective:To construct and purify four respiratory syncytial virus (RSV) PreF proteins through gene sequence design and optimization and evaluate their immunogenicity.Methods:Coronin-1A and T4 trimer protein gene sequences were optimized with Human and CHO codons, and then added to RSV F protein sequence. The above plasmids were transfected into Expi293F cells for protein expression. After purification by nickel column, four trimer proteins were prepared. SDS-PAGE and Western blot were performed for protein identification. BALB/c mice were immunized at week 0 and week 3, and blood samples were collected to measure the activities of binding and neutralizing antibodies in serum.Results:SDS-PAGE and Western blot showed that the four proteins had stable trimer structure. Antigen-antibody affinity test showed that the four trimer proteins had strong affinity with RSV-specific monoclonal antibodies 8897, D25, Motavizumab, AM14 and Palivizumab. The titers of antibodies induced by the two T4 trimers were higher after the initial immunization, while there was a substantial increase in the titers of antibodies induced by Human codon-optimized trimer protein after the second immunization.Conclusions:PreF trimer protein can be prepared by adding any of the two different heterotrimer motifs, and induce effective binding and neutralizing antibodies in mice.

Objective To explore the gene expression profile in paraspinal muscle degeneration(PMD)and identify key ferroptosis genes.Methods RNA sequencing was performed on paraspinal muscle tissue of 3 normal and 3 PMD patients respectively to obtain differentially expressed genes.Through protein-protein interaction(PPI)and gene functional enrichment analysis,the intersection of ferroptosis genes was identified to identify key hub genes associated with ferroptosis.The diagnostic value for PMD disease was analyzed by receiver operating characteristic(ROC)curves.Results A total of 292 differentially expressed genes were identified in PMD.Among them,125 genes were significantly downregulated and 167 genes were significantly upregulated.Bioinformatics analysis revealed that 14 differentially expressed genes were associated with ferroptosis.Among them,ferroptosis genes MUC1,ATF3 and CDKN1A were key hub genes with good specificity and sensitivity for diagnosing PMD.Functional enrichment analysis revealed that they may mediate the occurrence and progression of PMD by regulating cell apoptosis,ferroptosis and skeletal muscle tissue development and differentiation.Conclusion Ferroptosis genes MUC1,ATF3 and CDKN1A can serve as biomarkers for diagnosing PMD,providing theoretical basis for decoding the pathological mechanism of PMD and developing new drugs.

Objective:To establish a lumbosacral triangle (composed of L 5 transverse process, S 1 superior articular process, sacral ala and iliac crest) classification and to guide L 5S 1 endoscopic surgery. Methods:A total of 647 patients with low back pain who admitted to Tianjin Hospital from January 2016 to October 2018 were retrospectively analyzed, including 315 males and 332 females, aged 42.9±15.1 years (range, 19-74 years). The L 5 transverse process sacral distance (TSD), inter trans-verse process length (ITL), interlaminar width (ILW), interlaminar height (ILH), iliosacral angle (ISA), iliac crest height (IH), intervertebral space height (ISH), intervertebral foramen height (IFH), and intervertebral foramen width (IFW) were measured based on lumbar spine anterior-posterior and lateral radiographs. Spearman correlation analysis and hierarchical cluster analysis were used to establish the lumbosacral triangle classification. A total of 822 patients underwent endoscopic L 5S 1 surgery based on lumbosacral triangle classification guidance and verification in Tianjin Hospital from January 2020 to December 2022, including 421 males and 401 females, aged 45.1±16.7 years (range, 15-79 years). The visual analogue scale (VAS) and Oswestry disability index (ODI) were compared before and after surgery, and the Macnab criteria were used to assess surgical outcomes. Results:Spearman correlation analysis showed positive correlations between IH and ISA ( r=0.75, P<0.001), IFH and IFW ( r=0.60, P<0.001), TSD and IFH ( r=0.53, P<0.001), and TSD and IFW ( r=0.40, P<0.001). There was a negative correlation between TSD and IH ( r=-0.46, P<0.001), TSD and ISA ( r=-0.42, P<0.001), IFW and ISA ( r=-0.41, P<0.001), IFW and IH ( r=-0.50, P<0.001), IFH and IH ( r=-0.42, P<0.001). According to Spearman correlation analysis, hierarchical cluster analysis and receiver operating characteristic curve, lumbosacral angle was divided into three types: Type 1, L5 transverse process overlapped with sacral alar; Type 2, 07 mm. Based on lumbosacral triangle classification, different endoscopic techniques were used at L5S1 in 822 patients, including interlaminar approach single-axis endoscopy, trans-foraminal approach single-axis endoscopy, trans-foraminal fenestration approach mobile microendoscopy and unilateral biportal endoscopy, the VAS and ODI of all the patients decreased than those preoperative in immediate postoperative period, half a year postoperative period and the final follow up, and the difference was statistically significant ( P<0.05). At the last follow-up, the Macnab score was excellent in 278 cases, good in 475 cases, and fair in 69 cases, with an excellent and good rate of 91.6% (753/822). Conclusion:Lumbosacral triangle classification is simple and practical, and can effectively guide L5S1 endoscopic surgery.

Objective:To establish an artificial intelligence-based surgical selection system utilizing deep learning to assist in the decision-making process for lumbar endoscopic surgery.Methods:General data of 1,110 patients who underwent percutaneous transforaminal endoscopic discectomy, 804 patients who underwent percutaneous interlaminar endoscopic discectomy, 923 patients who underwent mobile microendoscopic discectomy and 623 patients who underwent unilateral biportal endoscopic in Tianjin Hospital from January 2018 to June 2023 were included in the study. Clinical outcomes were assessed using the visual analogue scale (VAS) for leg and back pain, the Oswestry disability index (ODI), and MacNab criteria both before surgery and 12 months postoperatively. Using a random number table method, patients were divided into a training dataset (2,768 cases) and a test dataset (692 cases) at a ratio of 4∶1. Patient clinical symptoms, physical signs, and multi-modal imaging data were input into a deep learning model. This model was structured into three main modules: intervertebral disc detection, surgical necessity identification, and surgical recommendation. The final surgical method was determined using a convolutional neural network incorporating U-Net for segmentation and ResNet for classification. The accuracy and recall rates of each module were evaluated using the test dataset.Results:Compared to preoperative values, all patients showed significant improvements at the 12-month postoperative follow-up. For patients who underwent percutaneous transforaminal endoscopic discectomy, percutaneous interlaminar endoscopic discectomy, mobile microendoscopic discectomy, and unilateral biportal endoscopic surgery, the VAS scores for leg pain decreased from 7.69±0.80, 7.82±0.88, 7.62±0.69, and 7.56±1.00 preoperatively to 1.44±1.09, 1.35±0.82, 1.51±1.08, and 1.43±0.91 postoperatively. Similarly, the VAS scores for back pain decreased from 5.73±0.83, 6.17±0.99, 6.11±0.88, and 6.46±0.95 to 0.93±0.75, 1.01±0.67, 1.40±0.72, and 1.27±0.70, respectively. Additionally, the ODI significantly decreased from 39.91%±4.50%, 40.05%±8.05%, 47.08%±9.50%, and 44.43%±4.71% preoperatively to 5.77%±2.22%, 6.05%±2.31%, 8.51%±2.16%, and 9.51%±3.70% postoperatively, with all differences being statistically significant ( P<0.05). The excellent rate according to the MacNab criteria was 93.12% (3,222/3,460). In the deep learning model, the multi-modal data of 2,768 patients were input in the training set for deep learning to form a surgical identification and operation recommendation system, and the preoperative data of 692 patients were input in the test set to compare with the final operation method. In the intervertebral disc location module, the accuracy of location and designation of the five lumbar intervertebral discs was 97.1%(672/692). In the module of intervertebral disc need for surgery, the accuracy was 94.8%(3,280/3,460) and the recall rate was 91.9%(636/692). As for patients, the accuracy rate was 91.9%(636/692). In the operation recommendation module, the accuracy rate of operation recommendation based on intervertebral disc was 89.5%(569/636), and the accuracy rate of surgical recommendation based on patient was 82.2%(569/692). Conclusion:In this study, an artificial intelligent surgical procedures selection system based on deep learning was established, which could effectively integrate relevant data and accurately guide the selection of lumbar endoscopic surgery.