BACKGROUND:Studies have shown that platelet-derived growth factor BB can stimulate the proliferation and osteogenic differentiation of mesenchymal stem cells and accelerate the calcification process of osteoblast-like cells.However,its clinical application has problems such as short half-life and easy decomposition.Loading the growth factor onto a suitable biomaterial scaffold can enable its slow and continuous release and maintain an effective concentration,which has become a hot topic in current research.OBJECTIVE:To observe the effect of chitosan/reduced graphene oxide scaffolds loaded with platelet-derived growth factor BB on the repair of alveolar bone defect in rats.METHODS:(1)Chitosan/reduced graphene oxide scaffolds(referred to as CS/rGO scaffolds)and chitosan/reduced graphene oxide scaffolds loaded with different mass concentrations(5,10,15,and 20 mg/L)of platelet-derived growth factor BB(referred to as CS/rGO/PDGF-BB-5,CS/rGO/PDGF-BB-10,CS/rGO/PDGF-BB-15,and CS/rGO/PDGF-BB-20 scaffolds)were prepared respectively.The five groups of scaffolds were co-cultured with rat periodontal ligament stem cells.The cell proliferation and migration were detected by CCK-8 assay and Transwell chamber assay,respectively,to screen the appropriate growth factor loading mass concentration for subsequent experiments.CS/rGO scaffolds(or extracts)and CS/rGO/PDGF-BB-15 scaffolds(or extracts)were co-cultured with rat periodontal ligament stem cells,and the osteogenic differentiation and angiogenic ability of the cells were detected.(2)The alveolar bone defect model was prepared in front of the bilateral maxillary first molars of 16 SD rats,and the rats were randomly divided into 4 intervention groups:the blank control group did not receive any intervention,the simple scaffold group was implanted with CS/rGO/PDGF-BB-15 scaffold,the control group was implanted with CS/rGO scaffold and rat periodontal ligament stem cell complex,and the experimental group was implanted with CS/rGO/PDGF-BB-15 scaffold and rat periodontal ligament stem cell complex,with 4 rats in each group.Twelve weeks after surgery,the bone repair of the alveolar bone defect was observed by Micro CT scanning and hematoxylin-eosin staining.RESULTS AND CONCLUSION:(1)CS/rGO/PDGF-BB-5,CS/rGO/PDGF-BB-10,CS/rGO/PDGF-BB-15,and CS/rGO/PDGF-BB-20 scaffolds could promote the proliferation and migration of rat periodontal ligament stem cells.Among them,the CS/rGO/PDGF-BB-15 scaffold had the most significant effect on promoting cell proliferation and migration,and this scaffold was used for subsequent experiments.Compared with the CS/rGO scaffold,the CS/rGO/PDGF-BB-15 scaffold could promote the osteogenic and angiogenic differentiation of rat periodontal ligament stem cells.(2)Micro CT scanning and hematoxylin-eosin staining results showed that the experimental group had the best alveolar bone defect repair effect,and a large amount of new bone tissue and blood vessel formation could be seen.(3)The chitosan/reduced graphene oxide scaffold loaded with platelet-derived growth factor BB can effectively promote the repair of rat alveolar bone defects by promoting the proliferation,migration,angiogenic and osteogenic differentiation of rat periodontal ligament stem cells.

BACKGROUND:Studies have shown that platelet-derived growth factor BB can stimulate the proliferation and osteogenic differentiation of mesenchymal stem cells and accelerate the calcification process of osteoblast-like cells.However,its clinical application has problems such as short half-life and easy decomposition.Loading the growth factor onto a suitable biomaterial scaffold can enable its slow and continuous release and maintain an effective concentration,which has become a hot topic in current research.OBJECTIVE:To observe the effect of chitosan/reduced graphene oxide scaffolds loaded with platelet-derived growth factor BB on the repair of alveolar bone defect in rats.METHODS:(1)Chitosan/reduced graphene oxide scaffolds(referred to as CS/rGO scaffolds)and chitosan/reduced graphene oxide scaffolds loaded with different mass concentrations(5,10,15,and 20 mg/L)of platelet-derived growth factor BB(referred to as CS/rGO/PDGF-BB-5,CS/rGO/PDGF-BB-10,CS/rGO/PDGF-BB-15,and CS/rGO/PDGF-BB-20 scaffolds)were prepared respectively.The five groups of scaffolds were co-cultured with rat periodontal ligament stem cells.The cell proliferation and migration were detected by CCK-8 assay and Transwell chamber assay,respectively,to screen the appropriate growth factor loading mass concentration for subsequent experiments.CS/rGO scaffolds(or extracts)and CS/rGO/PDGF-BB-15 scaffolds(or extracts)were co-cultured with rat periodontal ligament stem cells,and the osteogenic differentiation and angiogenic ability of the cells were detected.(2)The alveolar bone defect model was prepared in front of the bilateral maxillary first molars of 16 SD rats,and the rats were randomly divided into 4 intervention groups:the blank control group did not receive any intervention,the simple scaffold group was implanted with CS/rGO/PDGF-BB-15 scaffold,the control group was implanted with CS/rGO scaffold and rat periodontal ligament stem cell complex,and the experimental group was implanted with CS/rGO/PDGF-BB-15 scaffold and rat periodontal ligament stem cell complex,with 4 rats in each group.Twelve weeks after surgery,the bone repair of the alveolar bone defect was observed by Micro CT scanning and hematoxylin-eosin staining.RESULTS AND CONCLUSION:(1)CS/rGO/PDGF-BB-5,CS/rGO/PDGF-BB-10,CS/rGO/PDGF-BB-15,and CS/rGO/PDGF-BB-20 scaffolds could promote the proliferation and migration of rat periodontal ligament stem cells.Among them,the CS/rGO/PDGF-BB-15 scaffold had the most significant effect on promoting cell proliferation and migration,and this scaffold was used for subsequent experiments.Compared with the CS/rGO scaffold,the CS/rGO/PDGF-BB-15 scaffold could promote the osteogenic and angiogenic differentiation of rat periodontal ligament stem cells.(2)Micro CT scanning and hematoxylin-eosin staining results showed that the experimental group had the best alveolar bone defect repair effect,and a large amount of new bone tissue and blood vessel formation could be seen.(3)The chitosan/reduced graphene oxide scaffold loaded with platelet-derived growth factor BB can effectively promote the repair of rat alveolar bone defects by promoting the proliferation,migration,angiogenic and osteogenic differentiation of rat periodontal ligament stem cells.

Objective:To construct a hierarchical training course system for neonatal nurses based on core competencies, to provide a reference for meeting the training needs of neonatal nurses under the new situation.Methods:Through literature review, questionnaire survey on training needs, and focus group interviews, a preliminary hierarchical training curriculum system for neonatal nurses was developed. Two rounds of Delphi correspondence were conducted with 19 domestic experts to finalize the system.Results:The effective questionnaire recovery rates of the two rounds of expert consultation were 95.00% and 100.00%, and the expert authority coefficient was 0.916, the Kendall harmony coefficient of the first round of expert opinions was 0.351 ( P<0.001), and the Kendall harmony coefficient of the second round of expert opinions was 0.463 ( P<0.001). The hierarchical training course structure and course training content are formed, including N0: 3 first-level items, 9 second-level items, 80 third-level items, N1: 3 first-level items, 9 second-level items, 91 third-level items, N2: 3 first-level items, 9 second-level items, 86 third-level items, N3: 3 first-level items, 10 second-level items, 81 third-level items, N4: 3 first-level items, 10 second-level items, 76 third-level items. Conclusions:The hierarchical training course system for neonatal nurses based on the core competence of nurses is scientific and practical, which can provide a reference for the hierarchical training of neonatal nurses.

Objective:To construct a hierarchical training course system for neonatal nurses based on core competencies, to provide a reference for meeting the training needs of neonatal nurses under the new situation.Methods:Through literature review, questionnaire survey on training needs, and focus group interviews, a preliminary hierarchical training curriculum system for neonatal nurses was developed. Two rounds of Delphi correspondence were conducted with 19 domestic experts to finalize the system.Results:The effective questionnaire recovery rates of the two rounds of expert consultation were 95.00% and 100.00%, and the expert authority coefficient was 0.916, the Kendall harmony coefficient of the first round of expert opinions was 0.351 ( P<0.001), and the Kendall harmony coefficient of the second round of expert opinions was 0.463 ( P<0.001). The hierarchical training course structure and course training content are formed, including N0: 3 first-level items, 9 second-level items, 80 third-level items, N1: 3 first-level items, 9 second-level items, 91 third-level items, N2: 3 first-level items, 9 second-level items, 86 third-level items, N3: 3 first-level items, 10 second-level items, 81 third-level items, N4: 3 first-level items, 10 second-level items, 76 third-level items. Conclusions:The hierarchical training course system for neonatal nurses based on the core competence of nurses is scientific and practical, which can provide a reference for the hierarchical training of neonatal nurses.

With the increasing quantity of organ donors and the continual expansion of the definition of extended criteria donor (ECD) livers, the quality of donor liver has become a prominent issue affecting the high-quality development of liver transplantation, which is also the study focus in related fields. Resolving the shortage of organs to the maximal extent and promoting the high-quality development of organ transplantation lead the development direction of organ donation and transplantation in China. In recent years, the application of mechanical perfusion (MP) for the perfusion, preservation, evaluation and repair of donor liver has become a hot topic to improve the quality of liver transplantation within the international community. In this article, according to different conditions of the application of ECD livers in liver transplantation at home and abroad in combination with the research progress on MP in the international community and relevant research experience of our center, the feasibility of establishing an organ intensive care unit (ICU) with integrated organ protection techniques was discussed, aiming to promote the high-quality development of organ transplantation in China and further expand the technical connotation of the "Chinese model" of organ donation and transplantation.

Objective:To explore the influencing factors for non-alcoholic fatty liver disease (NAFLD) in Jinchang cohort, and provide scientific basis for the prevention and control of NAFLD.Methods:A total of 20 051 patients without fatty liver at baseline survey and met the inclusion criteria in Jinchang cohort were selected as study subjects. Prospective cohort study and Cox regression analysis were used to investigate the influencing factors for NAFLD, and the dose-response relationship between related biochemical indicators and NAFLD risk was studied by restricted cubic spline method.Results:The incidence of NAFLD was 42.37/1 000 person years. Multivariate Cox regression analysis showed that being worker and technical personnel (being worker: HR=0.84,95% CI:0.70-0.99;being technical personnel: HR=0.73,95% CI:0.56-0.95), tea drinking (current drinking: HR=0.86,95% CI:0.78-0.94;previous drinking: HR=0.52,95% CI: 0.31-0.86), exercise (occasionally: HR=0.79, 95% CI: 0.68-0.91;frequently: HR=0.60,95% CI:0.52-0.69), low body weight ( HR=0.10, 95% CI: 0.05-0.22), daily intake of dairy products >300 ml/day ( HR=0.78, 95% CI: 0.71-0.87) and HBV infection ( HR=0.77, 95% CI: 0.60-0.99) were the protective factors for NAFLD, while being internal or office workers ( HR=1.84, 95% CI: 1.46-2.31), income ≥2 000 yuan (2 000- yuan: HR=1.32, 95% CI: 1.04-1.66; ≥5 000 yuan: HR=1.72, 95% CI:1.11-2.66), bachelor degree or above ( HR=1.35,95% CI:1.03-1.76), overweight ( HR=2.31, 95% CI:2.08-2.55), obesity ( HR=3.95, 95% CI: 3.42-4.56), impaired fasting blood glucose ( HR=1.31, 95% CI:1.17-1.47), diabetes ( HR=1.53, 95% CI: 1.30-1.80), increased TC ( HR=1.37,95% CI:1.24-1.52), increased TG ( HR=1.79,95% CI: 1.62-1.98), decreased HDL-C ( HR=1.29, 95% CI: 1.14-1.45), increased ALT ( HR=1.13, 95% CI: 1.01-1.26) and high-fat diet ( HR=1.24, 95% CI: 1.11-1.40) were the risk factors for NAFLD. Moreover, TC, TG, HDL-C, ALT and FPG all showed good dose-response relationship with the incidence of NAFLD. Conclusion:Occupation, education level, income level, tea drinking, exercise, BMI, FPG, blood lipid, ALT, HBV infection and diet were related to the incidence of NAFLD.

The past few years have witnessed enormous progresses in the development of antibody-drug conju-gates (ADCs). Consequently, comprehensive analysis of ADCs in biological systems is critical in sup-porting discovery, development and evaluation of these agents. Liquid chromatography-mass spectrometry (LC-MS) has emerged as a promising and versatile tool for ADC analysis across a wide range of scenarios, owing to its multiplexing ability, rapid method development, as well as the capability of analyzing a variety of targets ranging from small-molecule payloads to the intact protein with a high, molecular resolution. However, despite this tremendous potential, challenges persist due to the high complexity in both the ADC molecules and the related biological systems. This review summarizes the up-to-date LC-MS-based strategies in ADC analysis and discusses the challenges and opportunities in this rapidly-evolving field.

Liver transplantation is the only effective treatment for portal hypertension (PHT) and end-stage liver disease.However,great therapeutic needs are far from satisfaction due to extreme shortage of donated livers.Good timing and indicator selection for PHT liver transplantation,and appropriate management of complications before or during on the waiting list,can avoid unnecessary liver transplantation and decrease the mortality rate of patients on waiting list.There are some particularities and issues worthy of attention.Understanding these particularities and handling these issues properly are extremely important to increase the success rate of PHT liver transplantation,enhance the recovery after surgery,and decrease the operative mortality.

Wuxistatin, a novel and potent statin, is converted from lovastatin by Amycolatopsis sp. CGMCC1149. In the bioconversion, lovastatin is firstly hydroxylated by a hydroxylase. To obtain the critical hydroxylase, a novel hydroxylase gene was isolated from Amycolatopsis sp. CGMCC1149 by Degenerate PCR and Self-Formed Adaptor PCR and expressed in Escherichia coli. BLAST sequence analysis revealed that the gene belonged to cytochrome P450 gene superfamily and could encode a 403-amino-acid protein with a molecular weight of 44.8 kDa. The secondary structure prediction result showed that this protein contained many typical functional regions of P450, such as oxygen binding site, ion-pair region and heme binding region. Meanwhile, a catalytic function verification system was constructed by NADH, ferredoxin and ferredoxin reductase which could catalyze lovastatin hydroxylation into the target product. These would be helpful for further studies in large-scale production of wuxistatin.
Actinomycetales ; enzymology ; genetics ; Amino Acid Sequence ; Butyrates ; metabolism ; Cloning, Molecular ; Cytochrome P-450 Enzyme System ; genetics ; metabolism ; Hydroxylation ; Industrial Microbiology ; Lovastatin ; metabolism ; Molecular Sequence Data