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.

[摘 要] 目的：探究长链非编码RNA（lncRNA）小核仁RNA宿主基因14（SNHG14）靶向miR-579-3p/富含半胱氨酸的酸性分泌蛋白（SPARC）对肝细胞癌（HCC）细胞恶性生物学行为的影响。方法：常规培养人正常肝细胞（LO2）和HCC细胞Huh7、Hep3B、HepG2，将Huh7细胞随机分为对照组、sh-NC组、sh-SNHG14组、sh-SNHG14 + anti-NC组和sh-SNHG14 + anti-miR-579-3p组，qPCR法检测细胞中SNHG14、miR-579-3p和SPARC mRNA的表达水平，双萤光素酶报告基因实验验证SNHG14与miR-579-3p及miR-579-3p与SPARC调控关系，MTT法、划痕愈合实验、Transwell实验、流式细胞术，以及WB法分别检测各组Huh7细胞的增殖、迁移、侵袭能力、凋亡，以及Huh7细胞中PCNA、E-cadherin、vimentin、SPARC蛋白的表达。结果：在HCC细胞中SNHG14、SPARC mRNA呈高表达、miR-579-3p呈低表达（均P < 0.05）；SNHG14与miR-579-3p和miR-579-3p与SPARC mRNA间存在直接结合调控关系（均P < 0.05）。敲减SNHG14可明显抑制Huh7细胞的增殖、迁移、侵袭、PCNA、vimentin、SPARC mRNA及蛋白的表达（均P < 0.05），促进细胞凋亡、miR-579-3p和E-cadherin表达（均P < 0.05）；抑制miR-579-3p则可部分逆转敲减SNHG14对Huh7细胞的作用（均P < 0.05）。结论：敲减SNHG14可通过靶向miR-579-3p/SPARC轴抑制Huh7细胞的恶性生物学行为，促进其凋亡；SNHG14和miR-579-3p/SPARC轴可能是HCC治疗的潜在靶点。

Aim To investigate the effect of safflower yellow on the learning and memory of scopolamine hydrobromide-induced memory impairment model mice.Methods 6-month-old C57BL/6J mice were randomly divided into the control group,model group,SY high-dose group,SY medium-dose group,SY low-dose group,and Huperzine-A group(12 mice in each group).SCOP was used to establish a memory impair-ment model,the spatial learning,memory and cognitive ability of mice with memory impairment were evaluated by behavioral experiments,the function of the choliner-gic nervous system in the cortex of mice was measured by ELISA kit,the pathological changes of brain tissue were observed by Nissl staining,and the expression of synaptic plasticity and BDNF/TrkB/CREB pathway re-lated proteins in the cortical and hippocampus of mice in each group was detected by Western blot.Results Compared with the model group,the learning and mem-ory ability of the mice in each administration group was improved.The neurons in the hippocampus and corti-cal were neatly arranged,the cell morphology tended to be complete,and the number of normal neurons in-creased.The function of the cortical cholinergic nerv-ous system was significantly improved,the expression of synaptic plasticity-related proteins in brain tissue was increased,and the BDNF/TrkB/CREB signaling path-way was activated.Conclusions SY can significantly improve the learning and memory ability of mice with SCOP-induced memory impairment,and its mechanism may play a neuroprotective role by improving choliner-gic nervous system function,activating BDNF/TrkB/CREB signaling pathway,regulating synaptic plasticity,and reduces neuronal damage.

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.

Here,5 important pathogens carried by ticks in Maanshan City,Anhui Province,China were identified.In to-tal,642 ticks were collected from 13 villages around Maanshan City and identified by morphological and mitochondrial COI genes.The 16S rRNA gene of Francisella tularensis,ssrA gene of Bartonella,16S rRNA,ompA and ompB genes of Rickett-sia,16S rRNA and gltA genes of Anaplasma,and groEL and rpoB genes of Coxiella were sequenced.Reference sequences were retrieved from a public database.Phylogenetic trees were constructed with MEG A1 1.0 software.In total,36 Rickettsiae isolates were detected in 640 Haemaphysalis longicornis ticks,which included 20 isolates of Rickettsia heilongjian-gensis,16 of Candidatus Rickettsia jingxinensis,2 of Ana-plasma bovis,and 186 of Coxiella-like endosymbiont.R.hei-longjiangensis HY2 detected in this study and Anhui B8 strain,Ca.R.jingxinensis QL3 and those from Shanxi Prov-ince and Jiangsu Province,A.bovis JX4 and those from Shanxi Province were clustered on the same branch.Overall,17 ticks had combined infections and none of the 5 bacteria were detected in two Amblyomma testudinarium ticks.This is the first report of Ca.R.jingxinensis detected in H.longicornis ticks from Anhui Province.It is recommended that the two types of Rickettsia that cause spotted fever and A.bovis should be reported to local health authorities to initiate appropriate prevention and control measures.

The effect of porcine SIRT5 on replication of foot and mouth disease virus type O(FMDV-O)and the underlying regulatory mechanism were investigated.Western blot and RT-qPCR analyses were employed to monitor expression of endoge-nous SIRT5 in PK-15 cells infected with FMDV-O.Three pairs of SIRT5-specific siRNAs were synthesized.Changes to SIRT5 and FMDV-O protein and transcript levels,in addition to virus copy numbers,were measured by western blot and RT-qPCR analyses.PK-15 cells were transfected with a eukaryotic SIRT5 expression plasmid.Western blot and RT-qPCR analyses were used to explore the impact of SIRT5 overexpression on FMDV-O replication.Meanwhile,RT-qPCR analysis was used to detect the effect of SIRT5 overexpression on the mRNA expression levels of type I interferon-stimulated genes induced by SeV and FMDV-O.The results showed that expression of SIRT5 was up-regulated in PK-15 cells infected with FMDV-O and siRNA interfered with SIRT5 to inhibit FMDV-O replication.SIRT5 overexpression promoted FMDV-O replication.SIRT5 over-expression decreased mRNA expression levels of interferon-stimulated genes induced by SeV and FMDV-O.These results suggest that FMDV-O infection stimulated expression of SIRT5 in PK-15 cells,while SIRT5 promoted FMDV-O rep-lication by inhibiting production of type I interferon-stimula-ted genes.These findings provide a reference to further ex-plore the mechanism underlying the ability of porcine SIRT5 to promote FMDV-O replication.

Objective:To evaluate the clinical and prognostic value of prothrombin time(PT)and activated partial thromboplastin time(APTT)in newly diagnosed patients with multiple myeloma(MM).Methods:The clinical data of 116 newly diagnosed MM patients in the Second Hospital and Third Hospital of Shanxi Medical University from October 2014 to March 2022 were analyzed retrospectively,and the patients were divided into two groups:normal PT and APTT group and prolonged PT or APTT group.The differences in sex,age,classification,staging,bleeding events,laboratory indicators[including hemoglobin(Hb),platelet count(PLT),serum calcium,serum albumin(ALB),lactate dehydrogenase(LDH),serum creatinine and β 2-microglobulin],and cytogenetic characteristics between the two groups of patients were compared.The effect of prolonged PT or APTT on survival of patients with MM was analyzed.Results:Compared with patients in normal PT and APTT group,patients in prolonged PT or APTT group were more likely to experience bleeding events(x2=5.087,P=0.024),with lower ALB levels(x2=4.962,P=0.026)and PLT levels(x2=4.309,P=0.038),and higher serum calcium levels(x2=5.056,P=0.025).The positive rates of del17p,del13q and 1q21+in prolonged PT or APTT group were higher than those in normal PT and APTT group,but the difference was not statistically significant(P＞0.05).K-M survival analysis showed that the prolonged PT or APTT group had a shorter median progression-free survival(PFS)(P=0.032)and overall survival(OS)(P=0.032).Multivariate Cox analysis showed that prolonged PT or APTT(HR=2.1 16,95％CI:1.025-4.372,P=0.043)and age ≥65 years(HR=2.403,95％CI:1.195-4.836,P=0.014)were independent risk factor for OS in newly diagnosed MM patients.However,prolonged PT or APTT had no significant effect on PFS of newly diagnosed MM patients(HR=1.162,95％CI:0.666-2.026,P=0.597).Conclusion:Newly diagnosed MM patients with prolonged PT or APTT have worse clinical indicators,shorter PFS and OS.Prolonged PT or APTT is an independent risk factor for OS in MM patients.

Objective:To report the results of national surveillance on the distribution and antimicrobial resistance profile of clinical Gram-positive bacteria isolates from bloodstream infections in China in 2022.Methods:The clinical isolates of Gram-positive bacteria from blood cultures in member hospitals of National Bloodstream Infection Bacterial Resistant Investigation Collaborative System（BRICS）were collected during January 2022 to December 2022. 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 software were used to analyze the data.Results:A total of 3 163 strains of Gram-positive pathogens were collected from 51 member units，and the top five bacteria were Staphylococcus aureus（ n=1 147，36.3%），coagulase-negative Staphylococci（ n=928，29.3%）， Enterococcus faecalis（ n=369，11.7%）， Enterococcus faecium（ n=296，9.4%）and alpha-hemolyticus Streptococci（ n=192，6.1%）. The detection rates of methicillin-resistant Staphylococcus aureus（MRSA）and methicillin-resistant coagulase-negative Staphylococci（MRCNS）were 26.4%（303/1 147）and 66.7%（619/928），respectively. No glycopeptide and daptomycin-resistant Staphylococci were detected. The sensitivity rates of Staphylococcus aureus to cefpirome，rifampin，compound sulfamethoxazole，linezolid，minocycline and tigecycline were all >95.0%. Enterococcus faecium was more prevalent than Enterococcus faecalis. The resistance rates of Enterococcus faecium to vancomycin and teicoplanin were both 0.5%（2/369），and no vancomycin-resistant Enterococcus faecium was detected. The detection rate of MRSA in southern China was significantly lower than that in other regions（ χ2=14.578， P=0.002），while the detection rate of MRCNS in northern China was significantly higher than that in other regions（ χ2=15.195， P=0.002）. The detection rates of MRSA and MRCNS in provincial hospitals were higher than those in municipal hospitals（ χ2=13.519 and 12.136， P<0.001）. The detection rates of MRSA and MRCNS in economically more advanced regions（per capita GDP≥92 059 Yuan in 2022）were higher than those in economically less advanced regions（per capita GDP<92 059 Yuan）（ χ2=9.969 and 7.606， P=0.002和0.006）. Conclusions:Among the Gram-positive pathogens causing bloodstream infections in China， Staphylococci is the most common while the MRSA incidence decreases continuously with time；the detection rate of Enterococcus faecium exceeds that of Enterococcus faecalis. The overall prevalence of vancomycin-resistant Enterococci is still at a low level. The composition ratio of Gram-positive pathogens and resistant profiles varies slightly across regions of China，with the prevalence of MRSA and MRCNS being more pronounced in provincial hospitals and areas with a per capita GDP≥92 059 yuan.

Objective:To evaluate the effect of activation of splenic plasmacytoid dendritic cells (pDCs) on myocardial ischemia-reperfusion (I/R) injury in mice.Methods:The experiment was performed in two parts. Animal experiment Thirty-six SPF healthy male C57BL/6J mice, aged 10 weeks, weighing 22-27 g, were assigned to 3 groups ( n=12 each) using a random number table method: sham operation group (Sham group), myocardial ischemia group (MI group) and myocardial I/R group (MI/R group). The myocardial ischemia was induced by occluding the left anterior descending coronary artery for 40 min in MI group, while the model of myocardial I/R was established by occlusion of the left anterior descending coronary artery for 40 min followed by 1-h reperfusion in MI/R group. Following successful preparation of the model, 3 animals from each group were randomly selected, and their hearts were removed for determination of myocardial infarct size through a combination of TTC and methylene blue double staining. Another 3 animals from each group were randomly selected, and their hearts were removed for examination of pathological changes of myocardial tissues using HE staining. Blood samples were collected from the abdominal aorta of 6 mice left in each group for determination of plasma interferon alpha (IFN-α) concentrations by enzyme-linked immunosorbent assay. Then the animals were sacrificed and hearts were harvested for collection of cardiac perfusate (CP). Cell experiment Twelve SPF healthy male C57BL/6J mice, aged 10 weeks, weighing 22-27 g, were selected and the splenic pDCs were isolated using anti-mPDCA-1 MicroBeads according to the manufacturer′s instructions (with a positivity rate of >85% for the isolated cells). The cells were divided into 4 groups: group pDCs stimulated by CP in Sham group (pDCs+ CP-Sham group), group pDCs stimulated by CP in MI group (pDCs+ CP-MI group), group pDCs stimulated by CP in MI/R group (pDCs+ CP-MI/R group) and pDCs stimulated by PBS group (pDCs+ PBS group). The CP in Sham, MI and MI/R groups and PBS were used to induce and culture pDCs for 8 h. Flow cytometry was employed to detect the expression of CD45 and co-stimulatory molecules CD80, CD86 and Major Histocompatibility Complex Ⅱ (MHC Ⅱ) on the surface of pDCs. The levels of IFN-α in the cell culture supernatant were determined using enzyme-linked immunosorbent assay. Results:Animal experiments Compared with Sham group and MI group, the percentage of myocardial infarct size was significantly increased, the concentrations of plasma IFN-α were increased ( P<0.05), and cardiomyocytes displayed evident vacuolar degeneration, severe myocardial fiber rupture, and infiltration of a substantial number of inflammatory cells in MI/R group. There was no significant difference in each parameter between Sham group and MI group ( P>0.05). Cell experiment Compared with pDCs+ CP-Sham group, the expression of CD80, CD86 and MHCⅡ was significantly up-regulated in pDCs+ CP-MI group ( P<0.05), and no significant change was found in the aforementioned parameters in pDCs+ CP-MI/R group ( P>0.05). The expression of aforementioned parameters was significantly up-regulated in pDCs+ CP-MI group as compared with pDCs+ CP-MI/R group ( P<0.05). Compared with pDCs+ CP-Sham group and pDCs+ CP-MI/R group, the concentrations of IFN-α in the cell culture supernatant were significantly increased in pDCs+ CP-MI group ( P<0.05). There was no statistically significant difference in the concentrations of IFN-α between pDCs+ CP-MI/R group and pDCs+ CP-Sham group ( P>0.05). Conclusions:The mechanism underlying myocardial I/R injury may be related to activation of splenic pDCs leading to the production of IFN-α following myocardial ischemia in mice.

Seminal microbiome plays an important role in male reproductive health,and its composition may be associated with sperm quality,development of oligoasthenospermia,and pregnancy outcomes of assisted reproductive technology.Seminal microbiome may be transmitted to the partner and offspring,and consequently affect female reproduction and the health of offspring.The complete structure of seminal microbiome is difficult to find by conventional bacterial culture due to the length of time taken and restriction of condition.Next-generation sequencing(NGS)can reveal the complete composition of seminal microbiome and help elucidate the com-plex microbial-host interactions based on human physiology and pathophysiology.This review focuses on the composition of seminal mi-crobiome,its relationship with male infertility and the mechanism of its impairing sperm quality based on NGS,and summarizes the re-sults of NGS-based studies on the patterns of bacterial colonization in different anatomical parts of the male reproductive tract.Current studies have revealed a unique diversity of seminal microbiome structures,a close correlation of abnormal seminal microbiome structure with sperm quality and male fertility,and a possible probiotic microbiome in semen capable of supporting health function.So far,the source and composition of seminal microbiome,and its influence on fertility and pregnancy outcome are not yet clear,and the specific mechanism of its diversity affecting sperm needs to be further studied with larger sample sizes and appropriate control specimens.