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.

Clinical death refers to the permanent cessation of life functions. This article reviews the definition of clinical death and the various scenarios in which it occurs, classifies the process of clinical death, and discusses the criteria for determining uncontrollable cardiac death, controllable cardiac death and the criteria and workflow for determining brain death. It elaborates on the relationship between brain death and death, and proposes the areas to note when standardizing the medical documentation of death cases. Based on this, it introduces the content of the management system and workflow construction for death determination in medical institutions, including management structure, personnel qualifications, document norms, quality control system and training mechanism. Paying attention to the construction of the management system and workflow for death determination in medical institutions is of great significance for ensuring medical quality and safety, promoting the healthy development of organ donation, and maintaining the seriousness of legal and ethical practices.

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 investigate the current status and influencing factors of moderate and severe injuries caused by falls among the elderly in Longhua District, Shenzhen City, Guangdong Province, so as to provide a basis for formulating prevention and control policies and intervention measures. Methods: Data on elderly patients (aged ≥60 years) who sought first-time outpatient or emergency treatment for falls at sentinel hospitals in Longhua District from January 1, 2021, to December 31, 2024, were collected through the Shenzhen Injury Surveillance System. The data included general information, basic characteristics of the fall incidents, and clinical characteristics of the fall-related injuries. Factors affecting moderate and severe injuries caused by falls among the elderly were analyzed using a multivariable logistic regression model. Results: A total of 2 797 elderly fall cases were reported in Longhua District from 2021 to 2024, including 990 males (35.40%) and 1 807 females (64.60%). The mean age was (70.56±8.85) years. There were 1 305 cases of moderate and severe injuries, accounting for 46.66%. Multivariable logistic regression analysis showed that female (OR=1.428, 95%CI: 1.211-1.684); 70-<80 years (OR=1.391, 95%CI:1.153-1.679), or ≥80 years (OR=1.586, 95%CI: 1.260-1.996); falls occurring at home (OR=1.659, 95%CI: 1.142-2.409), or in public residential settings (OR=1.666, 95%CI: 1.029-2.697); and activities during the fall such as walking (OR=1.738, 95%CI: 1.383-2.183) or performing life activities (OR=1.562, 95%CI: 1.254-1.947) were associated with a higher risk of moderate and severe injuries among elderly fall cases. High school/secondary technical school education level (OR=0.695, 95%CI: 0.526-0.919) and occupation as professional and technical/clerical staff (OR=0.540, 95%CI: 0.310-0.942) were associated with a lower risk of moderate and severe injuries among elderly fall cases. Conclusions The proportion of moderate and severe injuries caused by falls among the elderly in Longhua District is relatively high, which is mainly associated with gender, age, education level, occupation, fall location and activity during the fall.

Obesity represents a complex, heritable condition shaped by interactions among genetic, epigenetic, metagenomic, and environmental factors. Nevertheless, the mechanistic contributions of genetic variation and epigenetic regulation to obesity pathogenesis remain incompletely elucidated. Advances in molecular profiling technologies have enabled the identification of numerous biomarkers associated with childhood obesity phenotypes. These discoveries facilitate understanding of obesity etiology and its links to chronic diseases. This review synthesizes current research on genomic and epigenomic biomarkers influencing childhood obesity susceptibility, advances our comprehension of etiological heterogeneity and intervention strategies, and offers conceptual frameworks for precision prevention based on epigenetic mechanisms.

Lentiviral vectors(LVs)are key gene delivery tools for integrating target genes into the host genome,but they may also pose risks of insertional mutagenesis.The vector copy number(VCN)in cells is critical for determining the safety of gene modification.However,the reliability and accuracy of its quantification process are influenced by multiple factors.Developing cell reference materials with specific vector copy numbers represents a viable approach to enhance the reliability and consistency of measurement results,enabling quality control of the quantification process and traceability of outcomes.However,the preparation of such reference materials faces challenges in cell sample design,preparation protocols,and advanced quantification techniques.In this study,T lymphocyte cell line Jurkat-based reference materials with LV gene copy numbers of 1 and 2 copy/cell were developed.A high-precision duplex digital polymerase chain reaction(dPCR)method was established to quantify the LV gene and endogenous genes simultaneously.Additionally,the results of dPCR were cross-validated through next-generation sequencing and flow cytometric analysis.Ultimately,confocal microscopy characterization results showed that the developed cell reference materials had intact morphology.The quantification result of VCN-1 was(1.07±0.11)copy/cell,and that of VCN-2 was(2.09±0.21)copy/cell.These cell reference materials demonstrated compliance with stability and homogeneity requirements,and could be applied for quality control throughout the VCN measurement workflow and metrological traceability,improving the accuracy,comparability,and validity of copy number measurements.

Objective To investigate the influence of the liver failing to convey and disperse on space navigation aging.Methods High and low neuroticism subjects screened by Eysenck personality questionnaire were included in liver failing to convey and disperse group and liver controlling conveyance and dispersion group,respectively.The two groups were then divided into youth and elderly groups based on age.Finally,spatial navigation task was conducted to record and analyze behavioral(reaction time and accuracy)and EEG data(amplitude and latency of P2 and N2 components)of all the four groups(30 subjects each group).Results Compared with liver controlling conveyance and dispersion group,the accuracy in subjects with liver failing to convey and disperse decreased significantly(P<0.001)and reaction time was prolonged significantly(P<0.05).The interaction effect between age and liver regulation status showed a marginal significant difference(P=0.078).The accuracy of elderly people was lower than that of youth people(P=0.002)for liver failing to convey and disperse subjects,while there was no significant difference between the two groups for subjects with liver controlling conveyance and dispersion.The P2 amplitude in the elderly group was significantly smaller than that in the youth group(P=0.027).The amplitude of P2 in group of liver failing to convey and disperse was significantly smaller than that in group of liver controlling conveyance and dispersion(P=0.042).The interaction effect of P2 amplitude between age and liver regulation status showed a marginal significance(P=0.073).For youth subjects,the P2 amplitude in group of liver controlling conveyance and dispersion was significantly larger than that in group of liver failing to convey and disperse(P=0.007),while there was no significant difference in P2 amplitude between the two groups for the elderly subjects.The N2 amplitude for tasks of allocentric frames of reference was significantly greater than that of egocentric frames of reference(P=0.024).Conclusion Liver failing to convey and disperse caused by long-term emotional disturbance accelerates spatial navigation aging,and selective attention feature inhibition disorder may be the underlying ERPs neuroelectrophysiological mechanism.

Objective:To investigate the relationship between IUA occurrence and circRNA_0003031 by con-structing a mouse model of intrauterine adhesion(IUA).Methods:A mouse model of IUA was established by me-chanical curettage and lipopolysaccharide infection.The mice were divided into control group(NC group),IUA group,IUA+si-circRNA_0003031 group,and IUA+si-circRNA_0003031+miR-93-5p inhibitor group.The number of endometrial glands and the degree of fibrosis were determined using HE and Masson staining,respectively.Western blot test was used to detect the expression of ephthelial mesenchymal transition(EMT)marker proteins(vimentin,E-cadherin,N-cadherin),fibrosis-related molecules(collagen Ⅰ,collagen Ⅲ),α-smooth muscle actin(α-SMA),Transforming growth factor β1(TGF-β1),and receptors(TGF-β1R),Smad2,P-Smad2].Results:Compared with the IUA group,the number of endometrial glands increased,the degree of endometrial fibrosis de-creased in the IUA+si-circRNA_0003031 group(P＜0.05),and the protein expression of vimentin,N-cadherin,α-SMA,collagen Ⅲ,collagen Ⅰ,P-Smad2,Smad2,TGF-β1R,and TGF-β1 was down-regulated and E-cadherin was up-regulated(P＜0.05).Compared with the IUA+si-circRNA_0003031 group,in the IUA+si-circRNA_0003031+miR-93-5p inhibitor group,the number of endometrial glands was reduced and the degree of endometrial fibrosis was increased(P＜0.05),the protein expression of vimentin,N-cadherin,α-SMA,collagen Ⅲ,collagen Ⅰ,P-Smad2,Smad2,TGF-β1R,and TGF-β1 was up-regulated and E-cadherin was down-regulated,and the differences were statistically significant except for P-Smad 2(P＜0.05).Conclusions:CircRNA_0003031 may promote the oc-currence and development of IUA by inhibiting the expression of miR-93-5p and relieving its inhibitory effect on the TGFβ1/Smad2 signaling pathway.

Objective To investigate the influence of the and mechanism of liver failing to convey and disperse on age-related changes in attentional search based on ERPs.Methods oddball attention search task was administrated to record and analyze behavioral and EEG data(N2pc、SPCN、N2pc-Ptc components)of 120 subjects.Results Compared with liver controlling conveyance and dispersion group,the accuracy in subjects with liver failing to convey and disperse decreased significantly(P<0.05).The elderly group had a lower accuracy(P<0.001)and a longer reaction time(P<0.001)compared to the young group.The N2pc amplitude in subjects with liver failing to convey and disperse was significantly greater than that in subjects with liver controlling conveyance and dispersion(P<0.05).The interaction effect of SPCN amplitude between age and liver failing to convey and disperse status was significant(P=0.024).And in the elderly group,SPCN amplitude in subjects with liver dysregulation was significantly smaller than that of liver controlling conveyance and dispersion(P=0.042).The N2pc-Ptc peak to peak amplitude interaction effect between age and liver regulation status was marginal significant(P=0.087),and in liver failing to convey and disperse group,N2pc-Ptc peak to peak amplitude of the elderly was significantly smaller than that of the young(P=0.008).Conclusion Attention search ability is impaired in the elderly with liver failing to convey and disperse,and the electrophysiological abnormalities,such as directed attention allocation,spatiotemporal dynamic cohesion and short-term memory maintenance,may be part of the mechanism.

Obesity represents a complex, heritable condition shaped by interactions among genetic, epigenetic, metagenomic, and environmental factors. Nevertheless, the mechanistic contributions of genetic variation and epigenetic regulation to obesity pathogenesis remain incompletely elucidated. Advances in molecular profiling technologies have enabled the identification of numerous biomarkers associated with childhood obesity phenotypes. These discoveries facilitate understanding of obesity etiology and its links to chronic diseases. This review synthesizes current research on genomic and epigenomic biomarkers influencing childhood obesity susceptibility, advances our comprehension of etiological heterogeneity and intervention strategies, and offers conceptual frameworks for precision prevention based on epigenetic mechanisms.