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.

Objective:To report the nationwide surveillance results of pathogenic profiles and antimicrobial resistance patterns of Gram-positive bloodstream infections in China in 2023.Methods:The clinical isolates of Gram-posttive bacteria from blood cultures were collected in member hospitals of National Bloodstream Infection Bacterial Resistant Investigation Collaborative System（BRICS）during January to December 2023. Antimicrobial susceptibility testing was performed using the dilution method recommended by the Clinical and Laboratory Standards Institute（CLSI）. Statistical analyses were conducted using WHONET 5.6 and SPSS 25.0 software.Results:A total of 4 385 Gram-positive bacterial isolates were obtained from 60 participating center. The top five pathogens were Staphylococcus aureus（ n=1 544，35.2%），coagulase-negative Staphylococci（ n=1 441，32.9%）， Enterococcus faecium（ n=574，13.1%）， Enterococcus faecalis（ n=385，8.8%），and α-hemolytic Streptococci（ n=187，4.3%）. The prevalence of methicillin-resistant Staphylococcus aureus（MRSA）and methicillin-resistant coagulase-negative Staphylococci（MRCNS）was 26.2%（405/1 544）and 69.8%（1 006/1 441），respectively. Notably，all Staphylococci remained susceptible to glycopeptide or daptomycin. Staphylococcus aureus demonstrated excellent susceptibility（>97.0%）to cephalobiol，rifampicin，trimethoprim-sulfamethoxazole，linezolid，minocycline，tigecycline，and eravacycline. No Enterococcus exhibiting resistance to linezolid were detected. Glycopeptide resistance was uncommon but more frequent in Enterococcus faecium（resistance to vancomycin and teicoplanin：both 1.7%）compared to Enterococcus faecalis（both 0.3%）. The detection rates of MRSA and MRCNS exhibited significant regional variations across the country（ χ2=17.674 and 148.650，respectively，both P<0.001）. No vancomycin-resistant Enterococci were detected in central China. Institutional comparison demonstrated higher prevalence of MRSA（ χ2=14.111， P<0.001）and MRCNS（ χ2=4.828， P=0.028）in provincial hospitals than that in municipal hospitals. Socioeconomic analysis identified elevated detection rates of both MRSA（ χ2=18.986， P<0.001）and MRCNS（ χ2=4.477， P=0.034）in less developed regions（per capita GDP

Objective:To report the results of bacterial resistant investigation collaborative system（BRICS）on the distribution and antimicrobial resistance profile of clinical Gram-negative bacteria isolates from bloodstream infections in China in 2023，and provide reference for clinical tretment of bloodstream infections and prevention and control of bacterial resistance.Methods:The clinical isolates of Gram-negative bacteria from blood cultures in member hospitals of BRICS were collected during January 2023 to December 2023. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute（CLSI）. WHONET 5.6 and SPSS 25.0 were used to analyze the data.Results:During the study period，11 492 strains of Gram-negative bacteria were collected from 60 hospitals，of which 10 098（87.9%）were Enterobacterales and 1 394（12.1%）were non-fermentative bacteria. The top 5 bacterial species were Escherichia coli（50.0%）， Klebsiella pneumoniae（26.1%）， Pseudomonas aeruginosa（5.1%）， Acinetobacter baumannii complex（5.0%）and Enterobacter cloacae complex（4.1%）. The ESBL-producing rates in Escherichia coli， Klebsiella pneumoniae and Proteus mirablilis were 46.8%（2 685/5 741），18.3%（549/2 999）and 44.0%（77/175），respectively. The prevalence of carbapenem-resistant Escherichia coli（CREC）and carbapenem-resistant Klebsiella pneumoniae（CRKP）were 1.3%（76/5 741）and 15.0%（450/2 999）；32.9%（25/76）and 78.0%（351/450）of CREC and CRKP were sensitive to ceftazidime/avibactam combination，respectively. 94.7%（72/76）and 90.2%（406/450）of CREC and CRKP were sensitive to aztreonam/avibactam combination. Furthermore，57.9%（44/76）and 79.1%（356/450）were sensitive to imipenem/relebactam combination. The prevalence of carbapenem-resistant Acinetobacter baumannii（CRAB）complex was 64.6%（370/573），while more than 80.0% of CRAB complex was sensitive to tigecycline，eravacycline and polymyxin B. The prevalence of carbapenem-resistant Pseudomonas aeruginosa（CRPA）was 17.0%（99/581）. There were differences in the composition ratio of Gram-negative bacteria in bloodstream infections and the prevalence of important Gram-negative bacteria resistance among different regions in China，with statistically significant differences in the prevalence of CREC，CRKP，CRPA and CRAB complex（ χ2=10.6，28.6，10.8 and 19.3， P<0.05）. The prevalence of ESBL-producing Escherichia coli， CREC，CRAB complex and CRKP were higher in provincial hospitals than those in municipal hospitals（ χ2=12.5，9.8，12.7 and 57.8，all P<0.01）. Conclusions:Gram-negative bacteria are the main pathogens causing bloodstream infections in China，and Escherichia coli is ranked in the top，while the trend of Klebsiella pneumoniae increases continuously with time. CRKP infection shows a slow upward trend，CREC infecton maintains a low prevalence level，and CRAB complex infection continues to exhibit a high prevalence rate. The composition and resistance patterns of pathogens causing bloodstream infections vary to some extent across different regions and levels of hospitals in China.

BACKGROUND:Wolff's law points out that the lack of mechanical stress in the body will lead to the degradation of the microstructure of bone tissue,mass loss,and metabolic disorders,and eventually lead to osteoporosis,which suggests that mechanical stress plays an important role in the growth,reconstruction,and formation of bone tissue.At present,the relevant studies concerning mechanical stress on osteoblasts mainly focus on fluid shear force,but it is difficult to intervene in vivo.Meanwhile,some studies have found that compressive stress can also play a similar role in fluid shear force to a certain extent.Exploring the mode of action and influence of compressive stress on cells in vitro experiments can enrich the interaction relationship between mechanical stress and cells.It helps provide a theoretical basis for studies of metabolic bone diseases,including osteoporosis,and other diseases.OBJECTIVE:To review in vitro experiments,the application of compressive stress to cells,different biological behaviors caused by cells,the possible signaling pathways,and possible future applications.METHODS:We searched PubMed,Web of Science,CNKI,and WanFang databases from January 2000 to March 2024 to include all articles related to compressive stress on cells,including basic research and microscopic mechanism studies,using search terms"compressive stress,mechanical stress,hydrostatic pressure,cell"in Chinese and English.Finally,the 63 included articles were reviewed.RESULTS AND CONCLUSION:(1)There are various ways to apply compressive stress,and different experimental equipment has different ways of pressurizing cells,so it is necessary to further standardize the experimental equipment,standardize the pressurization unit,reduce the confounding factors,and make the reference and comparability between different experimental groups.(2)Compressive stress can cause changes in cell proliferation,differentiation,autophagy,apoptosis,migration,etc.,and the effect of compressive stress is time-or dose-dependent in most cases.(3)At present,most in vitro experimental studies have shown that compressive stress may mainly act on osteoblasts through MAPK signaling pathway and Wnt/β-catenin signaling pathway,causing osteoblasts to produce different responses.(4)The effect of compressive stress on different cells is not the same,and its possible biological effects need to be studied.(5)Further research on compressive stress is helpful to provide a theoretical basis for treatment in orthopedics,stomatology,tumors and other fields,and gentle disinfection using hydrostatic pressure is a promising disinfection method.

Objective To establish a high-performance liquid chromatography method to detect empagliflozin and related substances in empagliflozin bulk drug and tablets,and to provide technical support for quality control and unified monitoring of empagliflozin bulk drug and its tablets.Methods A liquid chromatography development system with the full factorial design of experiments and the Box-Behnken model was used to screen and optimize the chromatographic parameters.Related substances were detected in empagliflozin API and empagliflozin tablets from different companies with the optimized chromatographic parameters.Results The optimized chromatographic parameters were obtained:Shim-pack GIST C18-AQ column(250 mm×4.6 mm,5 μm)was used,column temperature was 15 ℃,gradient elution with water-acetonitrile as mobile phase was as below,flow rate was 1.2 mL·min-1,detection wavelength was set at 224 nm.The specificity of the method is good,with recoveries ranging from 94.8％to 101.7％,and RSD ranging from 0.5％to 3.1％.The known single impurity in APIs and tablets is less than 0.05％,any other unknown single impurity is less than 0.06％,and the total amount of impurities are less than 0.3％.The related substances of supervised sampling are under good control.Conclusion The method is reliable and robust for determining related substances of empagliflozin and its tablets.

Non-alcoholic fatty liver disease(NAFLD)is a chronic liver disease caused by excessive lipid accumulation in the liver.Its incidence rate is increasing year by year and has become an increasingly serious public healthy problem.The pathogenesis of NAFLD is complex and has not been fully clarified at present.It is mainly related to multiple factors such as genetics,metabolism,intestinal flora and immune response.In order to explore the medication rules and mechanism of action of traditional Chinese medicine(TCM)in the treatment of NAFLD,and to provide references for the treatment of NAFLD with TCM and the research and development of new drugs,this article summarizes the TCM pathogenesis of NAFLD(such as"phlegm and blood stasis interlacing","liver depression and spleen deficiency",etc.)and modern etiology and pathogenesis(such as insulin resistance,lipid disorder,mitochondrial dysfunction,oxidative stress,etc.).The clinical research and experimental data at home and abroad in recent years were integrated to analyze the pathological process of NAFLD intervention by TCM through multiple targets,including improving insulin resistance and lipid metabolism disorders,inhibiting oxidative stress and mitochondrial dysfunction,etc.TCM has shown unique advantages in the prevention and treatment of NAFLD.However,the depth of its mechanism analysis and the level of clinical research still need to be improved.In the future,it is necessary to deepen the mechanism research by combining multi-omics technology to accelerate the modernization development of TCM.

Objective To investigate the expression of small nuclear ribonucleoprotein D1 (SNRPD1) in the gastric cancer tissue and evaluate the predictive value of SNRPD1 expression level for the long-term prognosis of gastric cancer patients and the possible functioning mechanism of SNRPD1. Methods The UALCAN and Gene Expression Profiling Interactive Analysis (GEPIA) were employed to analyze the expression level of SNRPD1 in pan-cancer and its relationship with the prognosis of gastric cancer.The clinical data of 109 patients who underwent radical surgery for gastric cancer from January 2014 to January 2017 in the First Affiliated Hospital of Bengbu Medical University were retrospectively analyzed.Gastric cancer and paracancerous tissue samples were collected,and the expression of SNRPD1 was detected by immunohistochemical staining.Lentiviral transfection was employed to construct the BGC-823 gastric cancer cell models with stable high and low expression of SNRPD1,respectively.The CCK-8 assay and colony formation assay were employed to measure the proliferation of gastric cancer cells,and flow cytometry was used to analyze the cell cycle.Western blotting was employed to determine the expression levels of proteins in the signaling pathway. Results The data from UALCAN and GEPIA showed that SNRPD1 was highly expressed in the tissue of malignant tumors including gastric cancer (P<0.001).The expression level of SNRPD1 in the gastric cancer tissue was higher than that in the paracancerous tissue (P<0.001).Moreover,the expression level of SNRPD1 was positively correlated with the levels of carcinoembryonic antigen (P<0.001),carbohydrate antigen 19-9 (P<0.001),G stage (P=0.042),T stage (P=0.002),and N stage (P=0.027) in the patients with gastric cancer.The high expression of SNRPD1 had a predictive value for the long-term prognosis of gastric cancer (P<0.001),and it was an independent risk factor for the death of gastric cancer patients (P=0.003).The results of gene ontology and kyoto encyclopedia of genes and Genomes enrichment analyses showed that SNRPD1 was involved in the regulation of the cell cycle.The results of CCK-8 and colony formation assays showed that up-regulation of SNRPD1 promoted the proliferation of gastric cancer cells (P<0.001,P<0.001).The up-regulation of SNRPD1 up-regulated the expression of cyclin-dependent kinase 6 and G₁/S-specific cyclin-D1 (P<0.001,P=0.002),whereas the interference in SNRPD1 led to opposite results (P=0.004,P<0.001).SNRPD1 accelerated the G₁/S phase transition of gastric cancer cells (P<0.001).The overexpression of SNRPD1 promoted the expression of phosphorylated phosphatidylinositol 3-kinase (PI3K) and phosphorylated protein kinase B (Akt) in gastric cancer cells (P=0.043,P<0.001),whereas disruption of SNRPD1 inhibited their expression (both P<0.001).Insulin-like growth factor 1,an agonist of the PI3K/Akt signaling pathway,promoted the proliferation of gastric cancer cells with SNRPD1 disturbed (P=0.002). Conclusion High expression of SNRPD1 in the gastric cancer tissues is associated with poor prognosis,and it may promote tumor cell proliferation and regulate the cell cycle by activating the PI3K/Akt signaling pathway.
Humans ; Stomach Neoplasms/pathology* ; Prognosis ; Cell Line, Tumor ; Cell Proliferation ; Retrospective Studies ; Cell Cycle ; Male ; Female

Non-alcoholic fatty liver disease(NAFLD)is a chronic liver disease caused by excessive lipid accumulation in the liver.Its incidence rate is increasing year by year and has become an increasingly serious public healthy problem.The pathogenesis of NAFLD is complex and has not been fully clarified at present.It is mainly related to multiple factors such as genetics,metabolism,intestinal flora and immune response.In order to explore the medication rules and mechanism of action of traditional Chinese medicine(TCM)in the treatment of NAFLD,and to provide references for the treatment of NAFLD with TCM and the research and development of new drugs,this article summarizes the TCM pathogenesis of NAFLD(such as"phlegm and blood stasis interlacing","liver depression and spleen deficiency",etc.)and modern etiology and pathogenesis(such as insulin resistance,lipid disorder,mitochondrial dysfunction,oxidative stress,etc.).The clinical research and experimental data at home and abroad in recent years were integrated to analyze the pathological process of NAFLD intervention by TCM through multiple targets,including improving insulin resistance and lipid metabolism disorders,inhibiting oxidative stress and mitochondrial dysfunction,etc.TCM has shown unique advantages in the prevention and treatment of NAFLD.However,the depth of its mechanism analysis and the level of clinical research still need to be improved.In the future,it is necessary to deepen the mechanism research by combining multi-omics technology to accelerate the modernization development of TCM.

BACKGROUND:Wolff's law points out that the lack of mechanical stress in the body will lead to the degradation of the microstructure of bone tissue,mass loss,and metabolic disorders,and eventually lead to osteoporosis,which suggests that mechanical stress plays an important role in the growth,reconstruction,and formation of bone tissue.At present,the relevant studies concerning mechanical stress on osteoblasts mainly focus on fluid shear force,but it is difficult to intervene in vivo.Meanwhile,some studies have found that compressive stress can also play a similar role in fluid shear force to a certain extent.Exploring the mode of action and influence of compressive stress on cells in vitro experiments can enrich the interaction relationship between mechanical stress and cells.It helps provide a theoretical basis for studies of metabolic bone diseases,including osteoporosis,and other diseases.OBJECTIVE:To review in vitro experiments,the application of compressive stress to cells,different biological behaviors caused by cells,the possible signaling pathways,and possible future applications.METHODS:We searched PubMed,Web of Science,CNKI,and WanFang databases from January 2000 to March 2024 to include all articles related to compressive stress on cells,including basic research and microscopic mechanism studies,using search terms"compressive stress,mechanical stress,hydrostatic pressure,cell"in Chinese and English.Finally,the 63 included articles were reviewed.RESULTS AND CONCLUSION:(1)There are various ways to apply compressive stress,and different experimental equipment has different ways of pressurizing cells,so it is necessary to further standardize the experimental equipment,standardize the pressurization unit,reduce the confounding factors,and make the reference and comparability between different experimental groups.(2)Compressive stress can cause changes in cell proliferation,differentiation,autophagy,apoptosis,migration,etc.,and the effect of compressive stress is time-or dose-dependent in most cases.(3)At present,most in vitro experimental studies have shown that compressive stress may mainly act on osteoblasts through MAPK signaling pathway and Wnt/β-catenin signaling pathway,causing osteoblasts to produce different responses.(4)The effect of compressive stress on different cells is not the same,and its possible biological effects need to be studied.(5)Further research on compressive stress is helpful to provide a theoretical basis for treatment in orthopedics,stomatology,tumors and other fields,and gentle disinfection using hydrostatic pressure is a promising disinfection method.