BACKGROUND:The imbalance between bone resorption and bone formation in microgravity environments leads to significant bone loss in astronauts.Current research indicates that bone loss under microgravity conditions is the result of the combined effects of various cells,tissues,and systems. OBJECTIVE:To review different biological effects of microgravity on various cells,tissues,or systems,and summarize the mechanisms by which microgravity leads to the development of osteoporosis. METHODS:Databases such as PubMed,Web of Science,and the Cochrane Database were searched for relevant literature from 2000 to 2023.The inclusion criteria were all articles related to tissue engineering studies and basic research on osteoporosis caused by microgravity.Ultimately,85 articles were included for review. RESULTS AND CONCLUSION:(1)In microgravity environment,bone marrow mesenchymal stem cells tend to differentiate more into adipocytes rather than osteoblasts,and hematopoietic stem cells in this environment are more inclined to differentiate into osteoclasts,reducing differentiation into the erythroid lineage.At the same time,microgravity inhibits the proliferation and differentiation of osteoblasts,promotes apoptosis of osteoblasts,alters cell morphology,and reduces the mineralization capacity of osteoblasts.Microgravity significantly increases the number and activity of osteoclasts.Microgravity also hinders the differentiation of osteoblasts into osteocytes and promotes the apoptosis of osteocytes.(2)In a microgravity environment,the body experiences changes such as skeletal muscle atrophy,microvascular remodeling,bone microcirculation disorders,and endocrine disruption.These changes lead to mechanical unloading in the bone microenvironment,insufficient blood perfusion,and calcium cycle disorders,which significantly impact the development of osteoporosis.(3)At present,the mechanism by which microgravity causes osteoporosis is relatively complex.A deeper study of these physiological mechanisms is crucial to ensuring the health of astronauts during long-term space missions,and provides a theoretical basis for the prevention and treatment of osteoporosis.

BACKGROUND:The extracellular-regulated protein kinase 5(ERK5)signaling protein is essential for the survival of organisms,and resveratrol can promote osteoblast proliferation through various pathways.However,whether resveratrol can regulate osteoblast function through the ERK5 signaling protein needs further verification. OBJECTIVE:To explore the regulatory effect of ERK5 on the proliferation of MC3T3-E1 cells and related secreted proteins,and to further verify whether resveratrol can complete the above process by activating ERK5. METHODS:Mouse MC3T3-E1 preosteoblasts were treated with complete culture medium,XMD8-92(an ERK5 inhibitor),epidermal growth factor(an ERK5 activator),resveratrol alone,XMD8-92+EGF,and resveratrol+XMD8-92,respectively.Western blot assay was used to detect the expression of ERK5 and p-ERK5 proteins,proliferation-related proteins Cyclin D1,CDK4 and PCNA,and osteoblast-secreted proteins osteoprotegerin and receptor activator of nuclear factor-κB ligand in MC3T3-E1 cells of each group.The fluorescence intensity of ERK5,osteoprotegerin and receptor activator of nuclear factor-κB ligand in each group was detected by cell immunofluorescence staining,and cell proliferation was detected by EdU staining,respectively.The appropriate concentration and time of resveratrol intervention in MC3T3-E1 cells were determined by cell morphology observation and cell counting kit-8 assay. RESULTS AND CONCLUSION:The activation of ERK5 signaling protein could effectively promote the proliferation of MC3T3-E1 cells,up-regulate the osteoprotegerin/receptor activator of nuclear factor-κB ligand ratio.The appropriate concentration and time for resveratrol intervention in MC3T3-E1 cells was 5 μmol/L and 24 hours,respectively.Resveratrol could activate ERK5 signaling protein,thereby promoting osteoblast proliferation and up-regulating the osteoprotegerin/RANKL ratio.All these results indicate that resveratrol can promote the proliferation of MC3T3-E1 cells and up-regulate the osteoprotegerin/RANKL ratio by activating the ERK5 signaling protein.

In the context of the development of transplant oncology,it is of great clinical significance to find a drug with both antitumor and immunosuppressive effects for liver transplantation patients with hepatocellular carcinoma(HCC).The antitumor effect of ginkgolic acid(GA)has been confirmed,and some studies suggest that GA may also have an immunosuppressive effect.The immunosuppressive effect of GA was evaluated by histopathology,T-cell subpopulation,and cytokine detection in rat liver transplantation and mouse cardiac transplantation models,and transcriptomic and metabolomic analysis was used to explore the underlying mechanism of the GA immunosuppressive effect.Metabolites,activation,and ferroptosis markers of CD8+T cells were detected in vivo and in vitro.Based on rat liver transplantation and mouse cardiac transplantation models,the immunosuppressive effect of GA was first confirmed by histopathology,T-cell subpopulation,and cytokine detection.In the mouse cardiac transplantation model,transcriptomics combined with metabolomics demonstrated for the first time that GA inhibited lactate dehydrogenase A(LDHA)expression and pyruvate metabolism in CD8+T cells.It was confirmed in vivo and in vitro that GA inhibited pyruvate metabolism of CD8+T cells through LDHA,inhibiting their activation and inducing ferroptosis.Over-expression of LDHA partially reversed the effect of GA on the metabolism,activation,and ferroptosis of CD8+T cells in vitro.GA mediates metabolic reprogramming through LDHA to inhibit the activation and induce ferroptosis of CD8+T cells to exert an immunosuppressive effect,which lays an experimental foundation for the future clinical application of its immunosuppressive effect.

Objective To investigate the effects of periodontitis induced by Prevotella nigrescens(Pn)combined with ligation on cognitive functions in mice.Methods Twenty-four C57BL/6J mice were randomly divided into control group,ligation group,and ligation+Pn treatment(P+Pn)group.Experimental periodontitis was induced by silk ligation of the first molars followed by topical application of Pn for 6 weeks.After modeling,alveolar bone resorption was assessed using micro-CT and histological analysis.Learning and memory abilities of the mice were evaluated using open field test(OFT),novel object recognition test(NORT),and Morris water maze test(MWM).Seven weeks after the start of modeling,the mice were sacrificed for examining histopathological changes in the hippocampus using HE and Nissl staining.Results After 6 weeks of molar ligation,micro-CT revealed horizontal alveolar bone resorption and furcation exposure in the mice,and histological analysis showed apical migration of the junctional epithelium,epithelial ridge hyperplasia,and lymphocyte infiltration,and these changes were obviously worsened in P+Pn group.Alveolar bone height decreased significantly in both ligation groups compared to the control group.Cognitive tests showed that the mice in both of the ligation groups traveled shorter distances in OFT,showed reduced novel object preference in NORT,and exhibited longer escape latencies in MWM,and the mice in P+Pn group had significantly poorer performances in the tests.Histologically,obvious neuronal cytoplasmic degeneration,necrosis,nuclear pyknosis,vacuolation,and reduced Nissl bodies and viable neurons were observed in the hippocampal regions of the mice in the two ligation groups.Conclusion Pn infection aggravates alveolar bone destruction,accelerates necrosis and causes morphological abnormalities of neuronal cells in the hippocampus to reduce cognitive functions of mice with periodontitis.

Refinement and standardisation of the management of clinical diagnostic and treatment operations is a key aspect of achieving high-quality development in hospitals.By analysing the management status quo of clinical diagnosis and treatment operations in hospitals,it combed the problems existing in this field.Based on the closed-loop management model,it proposed measures and recommendations to promote the continuous optimisation of the management of clinical diagnostic operations in hospitals.Hospitals should establish hospital-level operation catalog and conduct classified management,authorize operators and dynamically adjust them,carry out operation quality management,pay attention to information management of operation management,and combine operation management with physician performance management.

Objective To design an 8-channel gene analyzer to take the place of the widely used gene analyzer with problems in inconvenient consumable replacement and short storage time of electrophoresis polymer.Methods The 8-channel gene analyzer had its mechanical components composed of an automatic sample loading table,a polymer injection module,a high-voltage temperature control module,an optical module and an integrated U box,its electrical control system made up of a host computer(an embedded computer)and three slave computers(a sampling control board,a polymer injection control board and a high-voltage temperature control board).The automatic sample loading table involved in four motors and transmission systems for x,y,z directions and optical alignment,the transmission systems adopted mainly belt drive mode and the optical alignment motor had its threads with an anti-backlash structure;the polymer injuection module was manipulated by the polymer injection control board,and the polymer block was made of highly transparent acrylic material;the high-voltage temperature control module realized the regulation of electrophoresis voltage and the detection of electrophoresis current by the low-ripple precision high-voltage power supply,and controlled the temperature of the heating furnace by the proportional-integral-differential(PID)algorithm;the optical module consisted of an excitation module and a light-receiving module,which had the base of the reflector made of low expansion coefficient alloy material;the integrated U box had the electrophoresis polymer,capillary array,polymer block and anode buffer in a plastic housing;the host computer had the data acquisition software programmed with C# and C++,and the slave computers were controlled by STM32 SCM.Results The 8-channel gene analyzer had no significant differences with the widely used ABI3500 gene analyzer in resolution,precision accuracy and clinical results.Conclusion The 8-channel gene analyzer gains advantages in consumable replacement and storage time of electrophoresis polymer,and can meet the requirements for gene sequencing.[Chinese Medical Equipment Journal,2025,46(2):24-30]

AIM:To optimize the clinical dosage and administration regimen of a novel long-acting injectable aripiprazole microsphere(LZMT05)using plasma concentration data from two clinical trials.METHODS:Plasma concentrations were collected from 196 schizophrenia patients administered LZMT05,and a population pharmacokinetic(Pop-PK)model was developed.The therapeutic window was defined as the steady-state trough-to-peak concentration range(94.0-534 ng/mL)of oral ar-ipiprazole.Multiple clinical scenarios were simulat-ed to identify the optimal regimen.RESULTS:A one-compartment model with dual first-order ab-sorption and first-order elimination characterized LZMT05 pharmacokinetics.Covariates like sex and CYP2D6 genotype were integrated into the final model.Simulations demonstrated that switching from 10 mg oral aripiprazole to 350 mg LZMT05 ev-ery 4 weeks sustained concentrations within the therapeutic window with minimal peak-to-trough fluctuations.CONCLUSION:The PopPK-guided opti-mized LZMT05 regimen maintained drug exposure within the therapeutic window,suggesting favor-able efficacy and safety.

Objective To establish a liver disease refined management platform encompassing hepatocellular carcinoma(HCC)screening for high-risk populations,longitudinal patient follow-up management,multidisciplinary team(MDT)consulta-tions for complex cases,and intelligent data analysis.This platform aims to achieve early detection and standardized management of individuals at risk of HCC,thereby improving the rates of curative treatment and patient survival.Methods Standardized data interfaces were utilized to integrate diverse medical data,including electronic health records,laboratory test results,and imaging reports.Multiple HCC risk assessment models were applied to assist clinicians in patient risk stratification and diagnosis.For un-diagnosed patients,personalized follow-up programs were implemented according to their risk categories.Clinical information of patients requiring MDT discussions was systematically collated to support comprehensive case evaluations.Results After the platform's introduction,a total of 6 187 patients were enrolled,accounting for 23.2％of outpatient attendees.The number of MDT discussions reached 351,representing a 46.3％year-on-year increase.The outcomes demonstrated significant improvements in the quality of liver disease management and diagnostic processes.Conclusion The platform can effectively achieve precise stratification of HCC risk groups,providing significant support for the early detection,diagnosis,and treatment of high-risk indi-viduals.Additionally,it offers a digital solution for facilitating the full-cycle precision management of liver disease patients,from screening to diagnosis treatment and follow-up.

BACKGROUND:Studies have confirmed that up-regulation of microRNA-140 expression can partially inhibit osteoarthritis-like changes in knee cartilage tissues and cells and delay the progression of osteoarthritis,suggesting that microRNA-140 is involved in the pathogenesis of osteoarthritis.OBJECTIVE:To further analyze the mechanism of microRNA-140 involvement in osteoarthritis by loading exosomes overexpressing microRNA-140 with sodium alginate/collagen hydrogel.METHODS:Lentivirus was used to infect rat bone marrow mesenchymal stem cells to overexpress microRNA-140,then exosomes were isolated and exosomes overexpressing microRNA-140 were obtained.Sodium alginate/collagen hydrogels loaded with exosomes were prepared.Thirty-two SD rats were randomly divided into four groups,with 8 rats in each group.Normal control group did not receive any treatment.The osteoarthritis model was established by injecting sodium iodoacetate into the knee cavity in the osteoarthritis group,the non-transfected exosome group and the transfected exosome group.Two weeks later,PBS was injected into the knee cavity in the osteoarthritis group.Sodium alginate/collagen hydrogel carrying non-overexpressing microRNA-140 and overexpressing microRNA-140 exosomes were injected into the knee cavity of the non-transfected exosome group and transfected exosome group.At 6 weeks after modeling,the threshold of mechanical foot withdrawal response,the concentration of inflammatory factors in synovial fluid,the expression of chondrogen-related genes,the histological changes of knee cartilage and the expression of pyroptosis related proteins were detected in rats.RESULTS AND CONCLUSION:(1)Compared with normal control group,the threshold value of mechanical stimulation foot contraction response,type Ⅱ collagen,SOX9 mRNA expression levels,and Type Ⅱ collagen immunofluorescence intensity were decreased in the osteoarthritis group(P<0.05),and proinflammatory cytokine levels were increased in synovial fluid(P<0.05).The mRNA expressions of matrix metalloproteinase 13 and a disintegrin and metalloproteinase with thrombospondin motifs-5(ADAMTS-5)were increased(P<0.05),and the protein expression levels of NLRP3,ASC,GSDMD p30,caspase-1 p20,interleukin-1β,and interleukin-18 were increased(P<0.05).Immunofluorescence intensity of GSDMD and cleaved caspase-1 was increased(P<0.05),and cartilage tissue was severely damaged.(2)Compared with osteoarthritis group,the threshold value of mechanical stimulation foot contraction response,type Ⅱ collagen,SOX9 mRNA expression levels,and type Ⅱ collagen immunofluorescence intensity in the non-transfected and transfected exosome groups were increased(P<0.05);proinflammatory cytokine levels were decreased in synovial fluid(P<0.05).The mRNA expression of matrix metalloproteinase 13 was decreased(P<0.05),and the protein expression levels of NLRP3,ASC,GSDMD p30,caspase-1 p20,interleukin-1β,and interleukin-18 were decreased(P<0.05).The immunofluorescence intensity of GSDMD and cleaved caspase-1 decreased(P<0.05),and the cartilage tissue damage was reduced(P<0.05),and the effect was stronger in the transfected exosome group.(3)These results conclude that microRNA-140 can reduce the pain response of rats with osteoarthritis by inhibiting inflammation,maintaining cartilage homeostasis,and inhibiting cartilaginous pyroptosis,thereby reducing cartilage damage and playing a therapeutic role in osteoarthritis.

Nitrogen oxides(NOx=NO+NO2)are important precursors of ozone(O3),and NOx and its oxides together constitute reactive nitrogen oxides(NOy)in the atmosphere.A comprehensive understanding of the total NOy level in the atmosphere is of great significance for a deeper understanding of the atmospheric nitrogen cycle and oxidation,as well as for formulating strategies for air pollution prevention and control.In this work,a thermal decomposition-broadband cavity enhanced absorption spectroscopy(TD-BBCEAS)technique for online measurement of total NOy in the atmosphere was developed.With this method,the NOy was efficiently converted into NO2,and the total NOy concentration in the atmosphere was indirectly obtained by measuring NO2.Focusing on the key factors affecting the measurement of total NOy,the influence of NO titration efficiency and other NOy component TD efficiency on measurement accuracy was emphasized.By changing the oxygen(O2)flow rate through the mercury lamp to alter the O3 concentration for titrating NO,the conversion efficiency of NO was evaluated.At O2 flow rate of 6 mL/min,the conversion efficiency of NO was greater than 99%.TD efficiency testing and analysis on NO2,peroxyacetyl nitrate(PAN),nitric acid(HNO3),and nitrous acid(HONO),which account for a large proportion of atmospheric NOy components,was carried out using 680℃as the optimal TD temperature for efficient conversion of NOy.With NO and HONO sample gases as typical verification gases,the conversion efficiency of NOy and the accuracy of NOy measurement by TD-BBCEAS system were verified by switching the on and off modes of mercury lamp and TD device.At integration time of 60 s,the detection limit of the system for NOy was 2.83×1010 molecules/cm3(60 s,2σ).A comparative measurement of actual atmospheric NOy was conducted between the TD-BBCEAS system and the NOy analyzer.The observation results showed a correlation coefficient(R2)of 0.98 and a slope of 0.93,further verifying the feasibility and accuracy of applying the TD-BBCEAS system to measurement of total NOy.