convalescents, and to screen for broad-spectrum neutralizing antibodies against the SARS-CoV-2 RBD. Methods Using biotinylated RBD as a molecular probe, flow cytometry was employed to perform single-cell sorting of B cells from peripheral blood mononuclear cells (PBMCs) of convalescents. The obtained B cells were lysed and subjected to reverse transcription, followed by nested PCR amplification of the heavy and light chains of antibodies was conducted using random primers. The amplified products were cloned into corresponding expression vectors, and the respective matched heavy-light chain plasmids were co-transfected into 293F cells for expression. Monoclonal antibodies were then purified using Protein A column chromatography. Neutralization experiments were conducted with the wild-type (WT) pseudovirus, and antibodies with IC50<0.1 μg/mL were selected for further testing of neutralizing breadth and potency against the wild-type (WT), Beta variant (B.1.351), Delta variant (B.1.617.2), and currently prevalent pseudovirus strains (XBB, BA.5, BF.7). Results A total of 21 RBD-specific monoclonal B cells were obtained from two recovered patients, resulting in the isolation of 13 pairs of antibody light/heavy chains. Nine antibodies were successfully expressed, with P1-A1, P1-B6, and P1-B9 exhibiting IC50 values below 0.1 μg/mL against the pseudovirus of the wild-type strain (WT). Specifically, P1-B6 effectively neutralized the wild-type strain (WT), Beta variant (B.1.351), and Delta variant (B.1.617.2), with IC50 values reaching 0.01 μg/mL. P1-B9 demonstrated effective neutralization against the wild-type strain (WT), Beta variant (B.1.351), Delta variant (B.1.617.2), and Gamma variant (P.1) pseudoviruses, with IC50 values of 0.42 μg/mL, 0.63 μg/mL, 0.28 μg/mL, and 2.50 μg/mL, respectively. Additionally, P1-B6 exhibited good neutralization against BA.5 and BF.7 pseudoviruses, with IC50 values of 0.06 μg/mL and 0.09 μg/mL, respectively. Conclusions Infection with the SARS-CoV-2 WT strain can induce the generation of neutralizing antibodies with broad-spectrum activity. Generating these broadly neutralizing antibodies does not require an excessively high somatic hypermutation. The obtained antibodies can be used as candidates for SARS-CoV-2 diagnosis and prevention.

BACKGROUND:Scaffold materials serve as platforms that provide space and structure,playing a crucial role in the regeneration of cartilage tissue.Scholars from around the world are exploring different approaches to fabricate more ideal scaffold materials. OBJECTIVE:To review the design principles and preparation methods of cartilage scaffolds,and to further explore the advantages and limitations of various preparation methods. METHODS:Literature searches were conducted on the databases of CNKI,WanFang Data,PubMed,and FMRS from 1998 to 2023.The search terms were"cartilage repair,cartilage tissue engineering,cartilage scaffold materials,preparation"in Chinese and English.A total of 57 articles were ultimately reviewed. RESULTS AND CONCLUSION:(1)The articular cartilage has a unique structure and limited self-repair capacity after injury.Even if self-repair occurs,the newly formed cartilage is typically fibrocartilage,which is far inferior to normal articular cartilage in terms of structure and mechanical properties.It is difficult to maintain normal function and often leads to degenerative changes.Currently,the design and fabrication of scaffold materials for cartilage repair need to consider the following aspects:biocompatibility and biodegradability,suitable pore structure and porosity,appropriate mechanical properties,and bioactivity.(2)Research on the preparation of cartilage scaffolds has made significant progress,continuously introducing new preparation methods and optimization strategies.These methods have their advantages and disadvantages,providing more possibilities for customized preparation and functional design of cartilage scaffolds according to specific requirements.

BACKGROUND:Bone formation is the process by which osteoblasts synthesize and secrete osteoid and promote its mineralization,which generally involves mechanical signal transduction.Osteoblasts are primarily regulated by mechanical factors such as gravity,compressive stress,tensile stress,fluid shear stress,and hydrostatic pressure in vivo,and different mechanical stimuli modulate the proliferation,differentiation,and apoptosis of osteoblasts through various mechanisms,including hormones,cytoskeletal proteins,and microRNAs.By clarifying the effects of biomechanical forces on osteoblasts,it provides ideas and a reference basis for the treatment of osteometabolic diseases involving osteoblasts. OBJECTIVE:To review the effects of different biomechanical forces on the biological characteristics of osteoblasts. METHODS:We conducted a literature search using PubMed,Web of Science,FMRS,CNKI,and WanFang databases for relevant publications published from 2000 to 2023,covering basic research and tissue engineering studies related to the effects of biomechanical forces on osteoblasts.Ultimately,a total of 70 articles were reviewed. RESULTS AND CONCLUSION:Different biomechanical forces have an impact on the biological characteristics of osteoblasts,including proliferation,differentiation,and apoptosis,and these effects are dependent on the intensity and duration of the applied force.Specifically,the effects are as follows:(1)Under microgravity conditions,osteoblast proliferation and differentiation are inhibited,resulting in a decrease in bone density and the development of osteoporosis.(2)Compared to microgravity,hypergravity has a promoting effect on osteoblast proliferation.(3)The effects of compressive stress on osteoblasts are dependent on the loading intensity and time.Appropriate compressive stress can promote osteoblast proliferation and differentiation,which is beneficial for bone tissue formation and repair,while excessive compressive stress can cause osteoblast apoptosis and bone tissue destruction.(4)The biological effects of different types of tensile stress on osteoblasts differ.Studies have shown that a strain rate within the range of 0-12%has a promoting effect on osteoblast proliferation.(5)Fluid shear stress can promote osteoblast proliferation and differentiation and enhance the bone-inducing effect of biomaterials.(6)Static hydrostatic pressure can affect the biological behavior of osteoblasts,including proliferation,differentiation,and apoptosis,and these effects are closely related to the time and intensity of the pressure.Understanding the effects of different biomechanical forces on osteoblasts is of great significance for a deeper understanding of bone growth and maintenance mechanisms.

Breast cancer remains a leading cause of mortality in women worldwide.Triple-negative breast cancer(TNBC)is a particularly aggressive subtype characterized by rapid progression,poor prognosis,and lack of clear therapeutic targets.In the clinic,delineation of tumor heterogeneity and development of effective drugs continue to pose considerable challenges.Within the scope of our study,high hetero-geneity inherent to breast cancer was uncovered based on the landscape constructed from both tumor and healthy breast tissue samples.Notably,TNBC exhibited significant specificity regarding cell prolif-eration,differentiation,and disease progression.Significant associations between tumor grade,prog-nosis,and TNBC oncogenes were established via pseudotime trajectory analysis.Consequently,we further performed comprehensive characterization of the TNBC microenvironment.A crucial epithelial subcluster,E8,was identified as highly malignant and strongly associated with tumor cell proliferation in TNBC.Additionally,epithelial-mesenchymal transition(EMT)-associated fibroblast and M2 macrophage subclusters exerted an influence on E8 through cellular interactions,contributing to tumor growth.Characteristic genes in these three cluster cells could therefore serve as potential therapeutic targets for TNBC.The collective findings provided valuable insights that assisted in the screening of a series of therapeutic drugs,such as pelitinib.We further confirmed the anti-cancer effect of pelitinib in an orthotopic 4T1 tumor-bearing mouse model.Overall,our study sheds light on the unique characteristics of TNBC at single-cell resolution and the crucial cell types associated with tumor cell proliferation that may serve as potent tools in the development of effective anti-cancer drugs.

Objective To monitor the susceptibility of clinical isolates to antimicrobial agents in tertiary hospitals in major regions of China in 2022.Methods Clinical isolates from 58 hospitals in China were tested for antimicrobial susceptibility using a unified protocol based on disc diffusion method or automated testing systems.Results were interpreted using the 2022 Clinical &Laboratory Standards Institute(CLSI)breakpoints.Results A total of 318 013 clinical isolates were collected from January 1,2022 to December 31,2022,of which 29.5％were gram-positive and 70.5％were gram-negative.The prevalence of methicillin-resistant strains in Staphylococcus aureus,Staphylococcus epidermidis and other coagulase-negative Staphylococcus species(excluding Staphylococcus pseudintermedius and Staphylococcus schleiferi)was 28.3％,76.7％and 77.9％,respectively.Overall,94.0％of MRSA strains were susceptible to trimethoprim-sulfamethoxazole and 90.8％of MRSE strains were susceptible to rifampicin.No vancomycin-resistant strains were found.Enterococcus faecalis showed significantly lower resistance rates to most antimicrobial agents tested than Enterococcus faecium.A few vancomycin-resistant strains were identified in both E.faecalis and E.faecium.The prevalence of penicillin-susceptible Streptococcus pneumoniae was 94.2％in the isolates from children and 95.7％in the isolates from adults.The resistance rate to carbapenems was lower than 13.1％in most Enterobacterales species except for Klebsiella,21.7％-23.1％of which were resistant to carbapenems.Most Enterobacterales isolates were highly susceptible to tigecycline,colistin and polymyxin B,with resistance rates ranging from 0.1％to 13.3％.The prevalence of meropenem-resistant strains decreased from 23.5％in 2019 to 18.0％in 2022 in Pseudomonas aeruginosa,and decreased from 79.0％in 2019 to 72.5％in 2022 in Acinetobacter baumannii.Conclusions The resistance of clinical isolates to the commonly used antimicrobial agents is still increasing in tertiary hospitals.However,the prevalence of important carbapenem-resistant organisms such as carbapenem-resistant K.pneumoniae,P.aeruginosa,and A.baumannii showed a downward trend in recent years.This finding suggests that the strategy of combining antimicrobial resistance surveillance with multidisciplinary concerted action works well in curbing the spread of resistant bacteria.

Sepsis is a syndrome of systemic inflammatory response in which the body′s response to infection is dysregulated, and is characterized by persistent infection, excessive inflammation and immunosuppression, etc. It often leads to organ dysfunction and can be life threatening, and also a common complication after trauma. The pathogenesis of post-traumatic sepsis is still unclear at present due to the complexity of its etiology, progression and prognosis. Multi-omics technology is a method to combine two or more single omics for comprehensive analysis, which can reveal the interaction network among the disease-associated molecules from multiple perspectives and aspects and is of great significance for the analysis of the pathogenesis of post-traumatic sepsis. To this end, the authors reviewed the research progress on the role of multi-omics technology in elucidating the pathogenesis of post-traumatic sepsis from the perspectives of genomics, transcriptomics, proteomics, metabolomics, single-cell transcriptomics and combination of multi-omics technologies, etc so as to provide a reference for the researches on post-traumatic sepsis.

Objective:To introduce and validate the Pediatric Nausea Assessment Tool (PeNAT) and the Baxter Retching Faces Scale (BARF) in the assessment of chemotherapy induced nausea in Chinese children with malignant neoplasms, and to explore the cut-off value for rescue antiemetic.Methods:A prospective descriptive study was conducted, 244 children in Sun Yat-sen University Cancer Center with malignant neoplasms who received chemotherapy were selected by convenience sampling from July to August 2021. PeNAT, BARF, Visual Analogue Scale (VAS) and the Faces Pain Scale-Revised(FPS-R) were used to assess the severity of nausea and pain before and after chemotherapy, before and 30-60 minutes after the use of rescue antiemetic or analgesic. After chemotherapy, the children also were asked the changes of nausea severity and whether antiemetic was needed.Results:A test-retest reliability was conducted on the patients with the same severity of nausea before and after chemotherapy, and the intraclass correlation coefficient of the PeNAT and BARF were 0.940 (both P<0.05). After chemotherapy, the PeNAT and BARF were 1.5(1.0, 2.0) and 2.0(0, 2.0) points, which were significantly higher than the 1.0(1.0, 1.0) and 0(0, 0) points before chemotherapy ( Z = - 9.19, - 9.09, both P<0.01). The PeNAT and BARF of 11 cases receiving antiemetic before medication were 4.0 (4.0, 6.0) and 3.0(2.0, 4.0) points, which were higher than the 0(0, 2.0) and 1.0(1.0, 2.0) points without antiemetic ( Z = - 4.03, - 3.86, both P<0.05). After chemotherapy, the correlation coefficients between PeNAT or BARF and VAS-nausea were r = 0.933, 0.957 (both P<0.01), and FPS-R were r = 0.192, 0.189 (both P<0.05). After using antiemetic, PeNAT and BARF were 2.0(2.0, 3.0) and 2.5(2.0, 4.0) points, which were significant different than the 3.0(3.0, 3.8) and 4.0(4.0, 8.0) points before using antiemetic ( Z = - 2.97, - 2.83, both P<0.05). According ROC curves and cut-off values, it was determined that PeNAT≥3 and BARF≥4 had clinical significance and require clinical intervention. Conclusions:PeNAT and BARF have excellent reliability and validity in the assessment of chemotherapy induced nausea in children with malignant neoplasms, they can effectively identify the requirement of rescue antiemetic, and evaluate the efficacy of antiemetic.

Objective:To focus on the physical activity strategy to maintain the activity ability of the elderly in the community, comprehensively retrieve and integrate the best evidence, form practical suggestions with the goal of the transformation and practice of evidence, so as to provide scientific, reliable and up-to-date basis for the implementation of relevant evidence.Methods:According to the 6S pyramid model, the British Medical Journal (BMJ) Best Practice, UpToDate, DynaMed, World Health Organization, Chinese Medical Association, National Institute for Health and Care Excellence, Scottish Intercollegiate Guidelines Network, New Zealand Guidelines Group, PubMed, SinoMed and other databases were retrieved layer by layer from top to bottom. This study obtained all articles of evidence-based knowledge base resources, clinical practice guidelines, expert consensus, systematic review and other types related to physical activity strategies to maintain the activity ability of the elderly in the community from January 1, 2017 to March 1, 2022. According to the inclusion and exclusion criteria of the article, 2 to 4 researchers conducted independent methodological quality evaluation on different types of article according to the tool requirements, extracted and summarized the best evidence, and formed practical suggestions.Results:A total of 14 articles were included, including 2 evidence-based decision-making, 6 guidelines, 1 expert consensus, 3 systematic reviews, and 2 overviews of systematic review. Seven dimensions such as "overall advice, health benefits, diversified sports training, aerobic training, balance training, muscle strengthening/resistance training, flexibility training" and 22 best pieces of evidence were extracted and summarized, and practical suggestions were formed.Conclusions:Medical and nursing staff should adopt evidence-based methodological practical suggestions to provide management guidance and consultation for the maintenance of physical activity ability of the elderly in the community, so as to help the elderly to maintain physical activity ability and gain health benefits.

Inflammatory reaction dominated by defense response will arise against infection and trauma. As an important proinflammatory cytokine, high mobility group box 1 (HMGB1) is widely expressed in all nuclear cells to mediate the inflammatory response. However, the biological functions of HMGB1 in inflammation vary depending on the type of HMGB1 protein modification and the localization in the cell. HMGB1 protein will be modified as acetylation of lysine residues, methylation of lysine residues, oxidation of cysteine residues, phosphorylation of serine residues, glycosylation of asparagine residues, adenosine diphosphate-ribosylation and lactylation of the protein in the nucleus, migrate from the nucleus to the cytoplasm, and release into the extracellular compartment. Extracellular HMGB1 can bind to receptors for advanced glycation end products (RAGE) and Toll-like receptors, activate cells and regulate inflammatory responses. The authors review the research progress in regulatory mechanism of HMGB1 in inflammation response from aspects of its post-translational modifications, releases, biological roles and binding receptors, hoping to provide theoretical basis for finding the targets of inflammation intervention.

Objective: To investigate the effects of terlipressin (TP) on blood pressure and survival in septic mice following trauma and its mechanism. Methods: ① Survival experiment: 120 male C57BL/6 mice aged 6-8 weeks were enrolled, the posttraumatic sepsis mice model was reproduced by traumatic hemorrhage (bilateral femoral fracture + 45% of total blood loss) followed by cecal ligation and puncture (CLP) after 8 hours. Intraperitoneal injection of TP was used for intervention. Sixty model mice were used to observe the effect of 0.05 μg/g TP at different intervention times (the drug was given immediately after traumatic hemorrhage + the administration was repeated after 6 hours, the drug was given immediately after traumatic hemorrhage + the administration was repeated every 6 hours until the end of the experiment, the drug was given at 4 hours after CLP + the administration was repeated every 6 hours until the end of the experiment) on 48-hour cumulative survival rate of mice with posttraumatic sepsis for finding the best intervention time of TP. The other 60 model mice were used to observe the effect of different TP intervention doses (0.01, 0.05, 0.25 μg/g) at the best intervention time on the 48-hour cumulative survival rate of mice with posttraumatic sepsis for finding the best intervention dose of TP. ② Intervention experiment: the other 45 mice were enrolled, and they were randomly divided into traumatic hemorrhage + sham group (TH+sham group, only laparotomy without CLP), TH+CLP group, and TH+CLP+TP group (the best intervention time and dose of TP shown by survival experiment were used), with 15 mice in each group. Mean arterial pressure (MAP) of mice was monitored continuously. The orbital whole blood was collected at 2 hours after successful reproduction of the model, and the lung tissues were harvested at 12 hours and 24 hours, respectively. The pathological changes in lung tissue were observed with light microscope. The contents of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) in serum and lung tissue were determined by enzyme linked immunosorbent assay (ELISA). The expressions of IL-1β and TNF-α mRNA in lung tissue were determined by real-time quantitative reverse transcription-polymerase chain reaction (RT-qPCR). The expressions of nuclear factor-κB p65 (NF-κB p65) in the nucleus and cytoplasm of lung tissue were determined by Western Blot. Results: ① Survival experiment results showed that the 48-hour cumulative survival rate of mice was highest with TP intervention by 0.05 μg/g administration immediately after traumatic hemorrhage and repeated every 6 hours, which was the best intervention method of TP. ② Intervention experiment results showed that the pulmonary alveolar wall fracture accompanied by inflammatory cell infiltration was found at 12 hours after the successful reproduction of traumatic sepsis model, and the pathological damage was gradually increased with time prolongation. MAP was decreased sharply after traumatic hemorrhage, and it was continued to decrease after two-hit of CLP. The contents of IL-1β and TNF-α in serum and lung tissue, the expressions of IL-1β and TNF-α mRNA in lung tissue, and expressions of NF-κB p65 protein in cytoplasm and nucleus of TH+CLP group were significantly higher than those in TH+sham group. Compared with TH+CLP group, the pathological changes in lung tissue were improved significantly, and the MAP was decreased gently after TP intervention, the levels of inflammatory mediators in serum were significantly decreased [IL-1β (pg/L): 164.32±25.25 vs. 233.11±23.02, TNF-α (pg/L): 155.56±31.47 vs. 596.38±91.50, both P < 0.05], and their expressions in lung tissue [IL-1β content (ng/mg): 262.68±16.56 vs. 408.15±17.85, IL-1β mRNA (2^-ΔΔCt): 2.63±0.68 vs. 6.22±0.74; TNF-α content (ng/mg): 311.07±17.35 vs. 405.04±24.83, TNF-α mRNA (2^-ΔΔCt): 2.04±0.62 vs. 5.32±0.55, all P < 0.01], and NF-κB p65 protein expressions were significantly down-regulated (gray value: 0.47±0.01 vs. 1.28±0.05 in cytoplasm, 0.45±0.02 vs. 1.95±0.06 in nucleus, both P < 0.01]. Conclusions The continuous intervention with TP 0.05 μg/g administration immediately after traumatic hemorrhage and repeated every 6 hours could improve the MAP of mice with traumatic sepsis, and improve the prognosis. The mechanism may be related to alleviating the inflammatory response and inhibiting the activation of the NF-κB signaling pathway in the lung tissue.