Inteins are unique protein insertion sequences capable of self-excision, enabling the covalent ligation of flanking extein peptides via amide bond formation. This process proceeds spontaneously without requiring external enzymes, cofactors, or chemical reagents, granting inteins exceptional biocompatibility and traceless performance in protein engineering applications. Split inteins represent a specialized and versatile subclass whose splicing domains are encoded by two separate gene fragments rather than a single continuous open reading frame. These fragments, known as the N-terminal (IntN) and C-terminal (IntC) split inteins, associate through non-covalent interactions including hydrophobic forces, hydrogen bonds, and van der Waals forces to assemble into an active three-dimensional structure, which then drives efficient extein ligation and enables protein trans-splicing. Protein trans-splicing mediated by split inteins has become a cornerstone for traceless protein ligation owing to its high specificity and irreversibility, fundamentally reshaping strategies for protein modification, assembly, and functional regulation. Compared with traditional chemical ligation methods, split intein systems require no complex chemical derivatization of peptide fragments and can operate efficiently at micromolar concentrations under physiological conditions, thus avoiding structural and functional damage caused by organic reagents. In contrast to enzymatic ligation tools such as sortase, split inteins eliminate the need for additional enzymes or cofactors, simplifying reaction systems, reducing costs, and minimizing non-specific side products. These distinctive advantages render split inteins highly promising for applications in chemical biology, synthetic biology, and biopharmaceutical development. In recent years, deepened mechanistic understanding has established structure-guided rational design as the primary approach to overcoming key limitations of split inteins, including intrinsic aggregation propensity, strict extein sequence dependence, and limited splicing efficiency. Bioinformatic tools have been used to identify aggregation-prone regions in the IntN fragment, and site-directed mutagenesis of hydrophobic residues, relocation of split sites, or removal of misfolding-prone sequences has substantially reduced in vitro aggregation and improved soluble expression and assembly activity. Rational engineering of catalytic residues and adjacent flexible loops has relaxed strict amino acid preferences at extein junctions, enhancing sequence tolerance and reducing the risk of functional impairment in target proteins. Consensus design based on multiple sequence alignments has yielded ultra-fast splicing variants such as Cfa DnaE and Cat-TerL, which exhibit significantly accelerated kinetics and improved tolerance to denaturing conditions. Meanwhile, advances in structural biology have further clarified the conformational dynamics and catalytic mechanisms of splicing, supporting the precise design of high-performance intein modules. On this basis, electrostatic interaction tuning and metagenomic screening have yielded multiple mutually orthogonal split intein pairs, enabling selective multi-fragment protein ligation and providing new routes for the efficient synthesis of large multi-domain functional proteins. With these engineered split inteins offering continuously improved performance and expanded applicability, protein trans-splicing has been widely applied in numerous cutting-edge areas of protein research and biomedicine. In gene delivery, split intein-based systems overcome the packaging limit of adeno-associated viral vectors, enabling the accurate reconstitution of large therapeutic proteins and base editors in target cells, thereby enhancing the efficacy and scope of gene therapy for genetic diseases. In internal protein sequence editing, split inteins mediate precise sequence replacement and modification in flexible regions or loops of target proteins, without the need for complex multi-step ligation and protein refolding involved in traditional protein semisynthesis. In protein-protein interaction studies, intein-mediated splicing covalently captures transient and weak intracellular complexes, enabling sensitive, high-throughput interaction detection and drug screening. In synthetic biology, conditionally controllable splicing systems support the construction of diverse intracellular and cell-surface biological logic gates for the precise regulation of cellular behavior. In mechanistic biochemical research, split inteins enable photocatalytic proximity labeling and site-specific tagging, allowing the preparation of homogeneous protein samples carrying precise post-translational modifications such as ubiquitination and polyglutamylation for chromatin interactome analysis and epigenetic studies. Moreover, covalent trapping strategies using split inteins stabilize transient enzymatic intermediates, providing unprecedented insights into molecular mechanisms such as nucleosome ubiquitination that are difficult to elucidate using conventional methods. This review systematically summarizes key technological advances in split inteins over the past decade, highlighting engineering strategies, mechanistic insights, and the development of orthogonal components. It comprehensively surveys emerging applications at the frontiers of protein research, analyzes current core challenges, and proposes future directions, particularly emphasizing artificial intelligence-driven de novo design and novel splicing pathways to break existing technical bottlenecks. By enabling traceless, efficient, and versatile protein manipulation, split inteins continue to serve as indispensable tools that drive innovation in protein engineering and fundamental life science research.

Neurocritical care involves complex pathophysiological mechanisms, and its incidence is higher, injuries are more severe, and treatment is more challenging in high-altitude environments. This consensus, based on the latest domestic and international evidence-based medical data, establishes a standardized, goal-oriented framework for neurocritical care management applicable in high-altitude regions and nationwide. The consensus was developed following international standards for evidence quality assessment and underwent two rounds of Delphi expert consultation, resulting in 32 recommendation statements covering three parts: management systems, monitoring and assessment, and core strategies. Key updates include: advocating for the establishment of independent neurocritical care units and implementing precise tiered diagnosis and treatment based on the "Five Differences in Critical Care" concept; constructing a "trinity" multimodal brain monitoring system centered on cerebral blood flow, cerebral oxygenation, and brain function, emphasizing routine bedside transcranial Doppler ultrasound, cerebral oximetry, and continuous electroencephalography monitoring; shifting management strategies from mild hypothermia therapy to targeted temperature management, and defining the "446" target management pathway for the supercritical stage; emphasizing the assessment of static and dynamic cerebrovascular autoregulation functions through multimodal methods to achieve individualized optimal mean arterial pressure management; elevating cerebrospinal fluid management goals to the level of "glymphatic system" function maintenance; implementing a multidisciplinary collaborative, whole-process management model focusing on patients' long-term neurological functional outcomes; de-escalation criteria include multidimensional indicators such as recovery of brain structure, restoration of cerebrovascular autoregulation, improvement in cerebrospinal fluid dynamics, and reduction in biomarker levels; and integrating cutting-edge technologies like artificial intelligence into post-critical care management and rehabilitation planning. This consensus systematically integrates the entire process of neurocritical care management, reflecting the modern connotation of goal-oriented, dynamic, and multimodal integration in neurocritical care medicine. It aims to adapt to new trends such as deepening understanding of pathophysiological mechanisms, the integration of medicine and engineering, and the empowerment of artificial intelligence, thereby further advancing the discipline of critical care medicine.

Objective: To explore the prevalence of bone defect and alveolar bone thickness changes in the mandibular incisors of untreated adults and post-orthodontic treatment adults, with the aim of providing strategies for preventing and managing alveolar bone defects during orthodontic treatment. Methods: This study was reviewed and approved by the Medical Ethics Committee. Clinical records, panoramic radiographs, cephalometric radiographs, and cone beam computed tomography (CBCT) images and informed consent were obtained for 150 untreated adults and 150 post-orthodontic adults. The untreated adults and post-orthodontic adults were respectively divided into three subgroups: skeletal ClassⅠ, Class Ⅱ and Class Ⅲ, with 50 cases per subgroup. Meanwhile, 60 cases with completeness of pre- and post-orthodontic data were enrolled from 150 post-orthodontic adults, including 20 cases each of skeletal ClassⅠ, Class Ⅱ, and Class Ⅲ. Cephalometric radiographs were imported into Dolphin software to measure skeletal parameters. CBCT images were imported into Mimics software to assess alveolar bone defects and to measure alveolar bone thickness of mandibular incisors among three groups: 150 untreated adult groups, 150 post-orthodontic groups and the pre- and post-treatment status of 60 patients selected from the latter group. Results: Untreated adult patients: the prevalence of labial dehiscence and fenestration in the mandibular incisors was higher than that on the lingual side among skeletal ClassⅠ, Ⅱ, and Ⅲ malocclusion patients, and there was a statistically significant difference in the alveolar bone thickness of the mandibular incisors among the three classes. Post-orthodontic treatment adults: for skeletal ClassⅠ and Ⅱ patients, the prevalence of lingual bone dehiscence in the mandibular incisors was significantly higher in the extraction groups than in the non-extraction groups; correspondingly, the lingual alveolar bone was also thinner in the extraction groups; Class Ⅱ non-extraction patients showed a higher prevalence of labial bone fenestration but a lower prevalence of lingual bone fenestration in mandibular incisors compared to Class Ⅱ extraction patients; the orthodontic-orthognathic combined treatment group showed significantly higher prevalence of labial/lingual bone dehiscence and thinner alveolar bone at multiple sites in the mandibular incisors compared to the camouflage group in skeletal Class Ⅲ patients. Comparison of mandibular incisor bone defects and thickness before and after orthodontic treatment in adult patients: in skeletal ClassⅠ and Ⅱ patients treated with premolar extraction and Class Ⅲ patients treated with orthodontic-orthognathic combined treatment, the lingual alveolar bone of mandibular incisors exhibited significant resorption and thinned after treatment, and this was accompanied by an increased prevalence of dehiscence; in non-extraction patients, ClassⅠ non-extraction patients showed thinning of the crestal-labial bone and apical-lingual bone, Class Ⅱ patients showed thinning of the crestal-labial bone and middle-labial bone of the mandibular incisors, along with an increased prevalence of dehiscence Conclusion In malocclusion adults, alveolar bone defects were already present in the mandibular incisors before orthodontic treatment. The alveolar bone defects and thickness in mandibular incisors among post-orthodontic adults were influenced by the treatment plan and Class of skeletal malocclusion.

ObjectiveTo investigate whether the effect of Danggui Shaoyaosan （DSS） on cognitive impairment is related to its promotion of ketone body metabolism in the brain and regulation of glutamate/α-amino-3-hydroxy-5-methyl-4-isox-azolepropionic acid receptor （AMPAR） pathway. MethodsMale APP/PS1 mice were randomized into model， low-dose （3.2 g·kg^-1） DSS， medium-dose （6.4 g·kg^-1） DSS， high-dose （12.8 g·kg^-1） DSS， ketogenic diet， and inhibitor （talampanel， 5 mg·kg^-1） groups. C57BL/6J wild-type mice were selected as the normal group. The talampanel group was intragastrically administered for 2 consecutive weeks from the 6th week， and the other groups were continuously treated for 8 weeks before behavioral testing. The ultrastructure of synapses in hippocampal CA1 region was observed by transmission electron microscopy， and calcium/calmodulin-dependent kinase Ⅱ （CaMKⅡ） expression was detected by immunohistochemistry （IHC）. The levels of β-hydroxybutyrate （BHB） and lactic acid （LAC） were measured by biochemical kits， and those of glutamate （Glu）， glutamine （Gln）， γ-aminobutyric acid （GABA）， and synaptophysin （SYP） by enzyme-linked immunosorbent assay （ELISA）. The mRNA levels of glutamine synthetase （GS）， glutaminase （GLS）， glutamate decarboxylase （GAD）， CaMKⅡ， and AMPAR subunits GluA1 and GluA2 were quantified by Real-time quantitative polymerase chain reaction （Real-time PCR）， and the protein levels of GS， GLS， GAD， GluA1， and GluA2 by Western blot. ResultsCompared with the normal group， the model group exhibited decreased recognition index， spontaneous alternation rate， and residence time in the target quadrant （P<0.01）， increased escape latency and ratio of the time in the opposite side of the target quadrant to the time in the target quadrant （P<0.05， P<0.01）， damaged synaptic ultrastructure of hippocampal CA1 region， increased positive expression of CaMKⅡ， no significant difference in BHB level， elevated LAC and Glu levels （P<0.01）， declined SYP， Gln， and GABA levels （P<0.01）， downregulated mRNA and protein levels of GS， GAD， and GluA2 （P<0.05， P<0.01）， and upregulated mRNA and protein levels of GLS and GluA1 （P<0.05， P<0.01） and mRNA level of CaMKⅡ （P<0.01）. Compared with the model group， DSS intervention improved the behavioral indexes of mice （P<0.05， P<0.01）， enhanced the synaptic ultrastructure plasticity in hippocampal CA1 region， decreased the positive expression of CaMKⅡ， raised the BHB level （P<0.01）， reduced the LAC and Glu levels （P<0.01）， elevated the SYP， Gln， and GABA levels （P<0.01）， upregulated the mRNA and protein levels of GS， GAD， and GluA2， and downregulated the mRNA and protein levels of GLS and GluA1 （P<0.05， P<0.01） and the mRNA level of CaMKⅡ （P<0.01）. ConclusionDSS can improve the learning and memory and enhance the synaptic plasticity of APP/PS1 mice. Its neuroprotective effect is coupled with the promotion of ketone body formation and remodeling of brain energy metabolism， and is related to the regulation of glutamate/AMPAR pathway.

Objective:To present a set of clinically representative quality assurance (QA) test cases for stereotactic radiosurgery (SRT) plans of multiple intracranial metastases, in order to assess the plan quality and machine execution capabilities.Methods:Based on the clinical characteristics of multiple brain metastases, four groups of test cases with three target volumes (TVs), six TVs, nine TVs, and TVs near organs at risk (OARs) were designed. For these cases, SRT plans were developed, and plan quality was assessed using metrics including the Radiation Therapy Oncology Group conformality index (RTOG CI), gradient index (GI), homogeneity index (HI), and the volume of normal brain tissue receiving a dose of 24 Gy ( V24 Gy), which was defined as the volume enclosed by the 24 Gy isodose line around the Brain-PTV ( V24 Gy of Brain-PTV). Verification plans were generated for each test case, including the verification of point doses, planar doses (PD), and SRS MapCHECK (SMC) semiconductor matrix planar doses. Compared with the calculated result of the treatment planning system (TPS), the criteria for the γ analysis of planar doses were set at 1 mm/2% and 2 mm/2%. Results:For the four groups of test cases, the mean CI, GI, HI, and V24 Gy of Brain-PTV were 1.04±0.03, 3.79±0.40, 0.73±0.01 and (7.46±3.80) cm 3, respectively. The mean deviations of the point doses were 0.88%±0.98%, 1.47%±0.79%, 1.52%± 0.76%, and 1.17% ± 0.38%, respectively. The mean γ passing rates of the single fields for PDs were greater than 98% at 2 mm/2% and exceeding 96% at 1 mm/2%, and the mean γ pass rates of the SMC semiconductor matrix for PDs were 97.75% ± 2.31% and 99.33% ± 0.62%, at 1 mm/2% and 2 mm/2% respectively. Conclusions:The proposed QA test cases for SRT of multiple intracranial metastases allow for the effective assessments of the plan quality and machine execution capabilities and, thus, can assist various centers in clinical applications.

Objective:To analyze the development trend of medical institution bed allocation in OECD countries and provide insights for optimizing bed resources allocation in China.Methods:Data on indicators of bed allocation and related factors from 1991 to 2022 were collected from the OECD online database.Bed allocation impact dimensions were identified based on health needs and demand theories.The random effect model and correlation analysis were used to explore influencing pathways of bed allocation.Results:The number of beds per 1 000 population and average life expectancy showed a significant positive correlation in countries below the average bed level,while an inverse trend was observed in countries above the average level.The number of long-term care beds per 1000 population showed positive correlation with average life expectancy.Multidimensional factors such as the disease spectrum and bed utilization efficiency were significant correlated with the bed allocation levels.The greater the gap in inpatient and outpatient reimbursement rations,the higher the demand for hospitalization among patients with chronic disease.Conclusions:An optimal number of beds is essential for achieving higher health outcomes.The bed classification planning system should be designed to adapt to demographic changes and strengthen the medical security support system.

Objective:To investigate the clinicopathological features and differential diagnosis of male genital system lympho-ma(MGSL).Methods:We retrospectively analyzed the clinicopathological and immunophenotypic features and prognosis of 80 ca-ses of MGSL.Results:The onset age of the MGSL patients ranged from 4 to 85(median 62)years old.All the cases showed non-specificity of the imaging features and clinical manifestations.MGSL was located mainly in the testis(n=66),followed by the pros-tate(n=7),epididymis(n=3),scrotum(n=3)and penile glans(n=1).Diffused large B cell lymphoma(DLBCL)was the most common pathological type(n=62),next came extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue(MALT)(n=7)and other rare types(n=12).During the 1-112-month follow-up of 10 of the 19 patients,1 died at 1 month af-ter diagnosed with prostatic B-lymphoblastic lymphoma(B-LBL)and another 1 died at 50 months after diagnosed with testicular DLBCL.Conclusion:MGSL is rare clinically,mainly of the DLBCL type pathologically,lacking specificity in clinical symptoms and imaging manifestation.The definite diagnosis of the malignancy depends on histopathology combined with related molecular exami-nation and immunohistochemical labeling,and R-CHOP chemotherapy is the first choice for its treatment.

Objective:To establish a standardized code database of adverse drug reactions (ADRs) terms related to linezolid and analyze the common ADRs of linezolid.Methods:Linezolid drug labels, websites (including Side Effect Resource, and the official websites of US Food and Drug Administration, European Medicines Agency and National Medical Products Administration) and scientific literature database (including CNKI, Wanfang, VIP, PubMed, Embase and Web of Science databases) were systematically searched, and ADR terms about linezolid were collected. ADR terms were mapped to the international classification of diseases-10 (ICD-10) code to establish a linezolid adverse reaction database.Results:A total of 117 ADR terms about linezolid were collected and 91 ICD-10 codes were obtained after being mapped to ICD-10. A standardized database was constructed and successfully embedded into the ADR spontaneous reporting system as a specific drug submodule. The gastrointestinal system, skin and subcutaneous tissue system, various nervous systems, blood and lymphatic systems were the most common system organs involved in linezolid-related ADRs under the 91 ICD-10 codes. Among them, ADRs under the gastrointestinal system codes K14.302 (black hairy tongue) and K52.104 (drug-induced gastroenteritis and colitis), the skin and subcutaneous tissue system code L27.005 (drug-induced dermatitis), various nervous system codes G90.800 (other disorders of autonomic nervous system), G62.001 (drug-induced polyneuropathy) and G44.400 (drug-induced headache, not elsewhere classified), the blood and lymphatic system codes D69.502 (drug- induced thrombocytopenia) and D70.x02 (drug-induced granulocytopenia), the metabolic and nutritional codes E87.204 (lactic acidosis), as well as the endocrine system code E16.000 (drug-induced hypoglycaemia without coma) had been reported frequently in the scientific literature. In addition, there were 14 ADR terms related to linezolid under 13 ICD-10 codes not recorded in the drug instructions.Conclusions:It is feasible to use ICD-10 code to standardize ADR terms related to linezolid and establish a database. Common ADRs of linezolid include thrombocytopenia, lactic acidosis, neutropenia, black hairy tongue, gastroenteritis/colitis, hypoglycemia, rash, serotonin syndrome, peripheral neuropathy and headache, which should be paid attention to and researched furtherly.

Objective To explore the short-term and long-term efficacy of partial splenic artery embolization(PSE)in the treat-ment of cirrhosis with hypersplenism.Methods A retrospective analysis was conducted on 35 patients with cirrhosis and hyper-splenism who underwent PSE treatment.Data on white blood cell(WBC),red blood cell(RBC),platelet count(PLT),hemoglobin(HGB),total bilirubin(TBiL),albumin(ALB),prothrombin time(PT),and D-dimer were collected at the three time points:before surgery,1 week after surgery,and 1 year after surgery.The changes in these parameters across the three time points were observed and compared.One-way ANOVA was used for repeated measurements,and time pairwise comparisons were made between the three time points.According to the formation of portal thrombosis,patients were divided into thrombus group and no-thrombus group.The D-dimer values were compared before surgery and 1 week after surgery.Results WBC and PLT were significantly higher 1 week and 1 year after surgery than those before surgery,with the most significant increase 1 week after surgery,and there was also statistically sig-nificant difference between 1 week after surgery and 1 year after surgery(P1,P2,P3<0.05).There were no significant differences in RBC and HGB between 1 week after surgery and before surgery(RBC P1=0.835,HGB P1=0.446).However,RBC and HGB 1 year after surgery were significantly higher than those before surgery and 1 week after surgery(RBC P2=0.039,P3=0.015;HGB P2=0.001,P3=0.010).There were significant differences in TBiL,ALB,PT,and D-dimer 1 week after surgery compared with those before surgery(TBiL P1=0.006,ALB P1<0.001,PT P1=0.001,D-dimer P1<0.001),but there was no significant differ-ence between 1 year after surgery and before surgery(all P2>0.05).The D-dimer of the thrombus group was significantly higher than that of the no-thrombus group 1 week after surgery,with a statistical significance(P=0.024),however,there was no signifi-cant difference in D-dimer between the two groups before surgery.Conclusion PSE in the treatment of cirrhosis with hypersplenism shows positive short-term and long-term efficacy for WBC and PLT.The short-term increase of RBC and HGB is not obvious,however the long-term efficacy is significant.In the short-term after surgery,TBiL increase,ALB decrease,PT prolonge,and liver reserve function decrease,but there was no long-term effect.The increase of D-dimer after surgery can easily induce portal thrombosis,and anticoagulation therapy can be given in the short-term after surgery.

Objective To investigate the impact of risk prevention and control on the quality efficiency of medical equipment procurement.Methods The medical equipment procurement projects with enhanced risk prevention measures during 2023(119 items)were assigned to an observation group,while those without strengthened risk control during 2022(118 items)were enrolled into a control group.The two groups were compared in terms of bid failure/rejection rates,procurement completion cycles(including procurement execution cycle and total procurement cycle)and procurement satisfaction.Statistical analysis was performed using SPSS 20.0 software.Results The observation group demonstrated significantly lower bid failure/rejection rates when compared with the control group(≥2 occurrences:5.88％vs.15.25％,P＜0.05).The procurement execution cycle was notably shorter in the observation group((69.16±78.65)d vs.(97.67±49.84)d,P＜0.05),though no significant difference was observed in total procurement cycle(P＞0.05).The observation group behaved better significantly than the control group in procurement efficiency,equipment performance,procedural compliance and post-purchase service satisfaction(all P＜0.05).Conclusion Risk prevention and control measures in medical equipment procurement effectively reduce bid failure/rejection risks while enhancing procurement quality efficiency.[Chinese Medical Equipment Journal,2025,46(3):81-85]