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.

ObjectiveThe human angiotensin converting enzyme2 （hACE2） transgenic mouse model was used to clarify the antiviral efficacy of BD-77 against a novel coronavirus SARS-CoV-2 and explore the action mechanism of BD-77 against SARS-CoV-2. MethodSARS-CoV-2 Omicron and Delta variant strains-infected VeroE6 cell models were established and administered with BD-77 to observe the antiviral effect of BD-77 in vitro. A kit was used to detect the effect of BD-77 in vitro on the binding of spike S protein of SARS-CoV-2 virus （Delta/Omicron） to angiotensin converting enzyme2 （ACE2）. Chromatography was adopted to detect the binding of BD-77 to the S protein and N protein of the novel coronavirus. hACE2 transgenic C57BL/6 mice were divided into a blank control group， SARS-CoV-2 infection group， BD-77 administration groups of 37.5 mg·kg^-1 and 75 mg·kg^-1， with eight mice in each group. The pneumonia model of SARS-CoV-2-infected hACE2 transgenic mice was built to observe the survival of the mice， detect the virus titer of the lung tissue of the mice， and observe the lesions in the lung tissue. ResultBD-77 had a certain inhibitory effect on Omicron and Delta variant strains in vitro， with median inhibitory concentration （IC₅₀） of 526.3 mg·L^-1 and 653.0 mg·L^-1， respectively. BD-77 had no significant inhibitory effect on the binding of the S protein of WT， Omicron， and Delta variant strains of SARS-CoV-2 to ACE2 and had no binding effect with the S protein and N protein of the novel coronavirus. No mice in the blank group died， while the mortality rate of SARS-CoV-2-infected mice was 75%. There was a large amount of virus replication in the lung tissue of the mice and large areas of inflammatory infiltration in the lung tissue and interstitium. Compared with the model group， BD-77 administration groups of 37.5 mg·kg^-1 and 75 mg·kg^-1 could reduce the mortality of mice， significantly lower the virus titer in the lung tissue of mice （P<0.05）， and improve lung lesions. ConclusionBD-77 demonstrated significant inhibitory effects against SARS-CoV-2 virus in vitro and in vivo. However， its mechanism of action did not involve direct inhibition of the virus itself or intervention in the virus-host binding process. This finding suggests that the mechanism of action of BD-77 needs to be thoroughly investigated and elucidated by further experiments.

Objective:To report the results of national surveillance on the distribution and antimicrobial resistance profile of clinical Gram-negative bacteria isolates from bloodstream infections in China in 2022.Methods:The clinical isolates of Gram-negative 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:During the study period，9 035 strains of Gram-negative bacteria were collected from 51 hospitals，of which 7 895（87.4%）were Enterobacteriaceae and 1 140（12.6%）were non-fermenting bacteria. The top 5 bacterial species were Escherichia coli（ n=4 510，49.9%）， Klebsiella pneumoniae（ n=2 340，25.9%）， Pseudomonas aeruginosa（ n=534，5.9%）， Acinetobacter baumannii complex（ n=405，4.5%）and Enterobacter cloacae（ n=327，3.6%）. The ESBLs-producing rates in Escherichia coli， Klebsiella pneumoniae and Proteus spp. were 47.1%（2 095/4 452），21.0%（427/2 033）and 41.1%（58/141），respectively. The prevalence of carbapenem-resistant Escherichia coli（CREC）and carbapenem-resistant Klebsiella pneumoniae（CRKP）were 1.3%（58/4 510）and 13.1%（307/2 340）；62.1%（36/58）and 9.8%（30/307）of CREC and CRKP were resistant to ceftazidime/avibactam combination，respectively. The prevalence of carbapenem-resistant Acinetobacter baumannii（CRAB）complex was 59.5%（241/405），while less than 5% of Acinetobacter baumannii complex was resistant to tigecycline and polymyxin B. The prevalence of carbapenem-resistant Pseudomonas aeruginosa（CRPA）was 18.4%（98/534）. There were differences in the composition ratio of Gram-negative bacteria in bloodstream infections and the prevalence of main Gram-negative bacteria resistance among different regions，with statistically significant differences in the prevalence of CRKP and CRPA（ χ2=20.489 and 20.252， P<0.001）. The prevalence of CREC，CRKP，CRPA，CRAB，ESBLs-producing Escherichia coli and Klebsiella pneumoniae were higher in provinicial hospitals than those in municipal hospitals（ χ2=11.953，81.183，10.404，5.915，12.415 and 6.459， P<0.01 or <0.05），while the prevalence of CRPA was higher in economically developed regions（per capita GDP ≥ 92 059 Yuan）than that in economically less-developed regions（per capita GDP <92 059 Yuan）（ χ2=6.240， P=0.012）. Conclusions:The proportion of Gram-negative bacteria in bloodstream infections shows an increasing trend，and Escherichia coli is ranked in the top，while the trend of CRKP decreases continuously with time. Decreasing trends are noted in ESBLs-producing Escherichia coli and Klebsiella pneumoniae. Low prevalence of carbapenem resistance in Escherichia coli and high prevalence in CRAB complex have been observed. The composition ratio and antibacterial spectrum of bloodstream infections in different regions of China are slightly different，and the proportion of main drug resistant bacteria in provincial hospitals is higher than those in municipal hospitals.

Objective To analyze the therapeutic effect and mechanism of Cangfu Daotan Decoction on obese polycystic ovary syndrome(PCOS)rats.Methods Fifteen female SD rats were randomly divided into normal group,model group and Chinese medicine group,with five rats in each group.In addition to the normal group,the remaining rats were treated with Letrozole Solution by gavage combined with high-fat diet to construct an obese PCOS model.After successful modeling,the rats in the Chinese medicine group were given Cangfu Daotan Decoction by gavage for 30 days.At the end of administration,the ovarian protein expression of rats in each group was detected by non-standard proteomics quantitative technique,and the results of differential protein function,gene ontology(GO)enrichment,Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment and differential protein KEGG pathway clustering were compared.Results The functions of differential proteins between the model group and the normal group were mainly concentrated in lipid transport,metabolism and post-translational modification,and protein transcription,and the cluster analysis results of KEGG pathway enrichment and pathway enrichment were mainly concentrated in the degradation of valine,leucine and isoleucine,arginine and proline metabolism,tryptophan metabolism pathway enrichment and renin angiotensin system.The functions of differential proteins between the Chinese medicine group and the model group were concentrated in information storage and processing,especially in transformation,ribosomal structure and signal transduction mechanism,and the cluster analysis results of KEGG pathway enrichment and pathway enrichment were mainly concentrated in ribosome metabolism,drug metabolism-cytochrome P450,methyl butyrate metabolism,and vitamin B6 metabolism.The functional classification of differential proteins between Chinese medicine group and normal group was mainly in signal transduction mechanism,lipid transport and metabolism,and the clustering analysis results of KEGG pathway enrichment and pathway enrichment were mainly concentrated in ribosome,protein digestion and absorption,steroid hormone biosynthesis pathway,cell adhesion molecule,glycerol lipid metabolism and gastric acid secretion.Conclusion Cangfu Daotan Decoction may play a role in the treatment of obese PCOS by regulating branched-chain amino acid metabolism,renin-angiotensin-aldosterone system and steroid hormone synthesis pathway.

Objective:To understand the iodine nutritional status of Hohhot residents, and to provide a basis for scientific prevention and control of iodine deficiency disease and reasonable iodine supplementation.Methods:The stratified cluster sampling method was used to conduct a survey on the iodine nutritional status of residents in 9 banners (counties and districts) of Hohhot City in 2022. Each flag (county, district) was divided into 5 sampling areas according to the east, west, south, north and center directions, and 1 school was selected from each area, 40 children aged 8 to 10 years old were selected from each school (balanced in terms of age, half of both sexes), and 100 pregnant women (balanced in the early, middle and late stages of pregnancy) were selected from each flag (county, district), and the salt samples of household salt were collected as well as random urine samples for the determination of salt iodine and urine iodine content. In 3 randomly selected banners (counties and districts), 40 children were selected from each banner (county and district) and their thyroid volume was measured using ultrasound.Results:A total of 2 710 salt samples of edible salt were collected, including 32 samples of non-iodized salt, with a median salt iodine of 21.6 mg/kg, an iodized salt coverage rate of 98.7% (2 675/2 710), and a qualified iodized salt consumption rate of 92.8% (2 515/2 710). There are 1 803 salt samples from children's homes, with a median salt iodization of 21.9 mg/kg, the iodized salt coverage rate was 99.1% (1 786/1 803), and the consumption rate of qualified iodized salt was 93.1% (1 678/1 803). Nine hundred and eight salt samples of edible salt were collected from the homes of pregnant women. The median salt iodine was 21.4 mg/kg, the iodized salt coverage rate was 98.0% (890/907), and the consumption rate of qualified iodized salt was 92.2% (837/907). The median urinary iodine for children and pregnant women was 198.5 and 169.9 μg/L. The rate of goiter in children was 3.6% (22/602).Conclusion:In 2022, residents of Hohhot are at the appropriate level of iodine, salt iodine coverage, urinary iodine for children and pregnant women, and goiter rate for children are all in line with the standard for elimination of iodine deficiency diseases, and iodine deficiency diseases are in a state of continuous elimination.

Objective:To optimize the technical parameters related to the preparation of novel frozen human platelets and formulate corresponding protocol for its preparation.Methods:Novel frozen human platelets were prepared with O-type bagged platelet-rich plasma(PRP),the key technical parameters(DMSO addition,incubation time,centrifugation conditions,etc.)of the preparation process were optimized,and the quality of the frozen platelets was evaluated by routine blood tests,apoptosis rate,platelet activation rate and surface protein expression level.Results:In the preparation protocol of novel frozen human platelets,the operation of centrifugation to remove supernatant was adjusted to before the procedure of platelets freezing,and the effect of centrifugation on platelets was minimal when the centrifugation condition was 800 xg for 8 min.In addition,platelets incubated with DMSO for 30 min before centrifugation exhibited better quality after freezing and thawing.The indexes of novel frozen human platelets prepared with this protocol remained stable after long-term cryopreservation.Conclusion:The preparation technique of novel frozen human platelets was established and the protocol was formulated.It was also confirmed that the quality of frozen platelets could be improved by incubating platelets with DMSO for 30 min and then centrifuging them at 800 ×g for 8 min in the preparation of novel frozen human platelets.

Patients with severe trauma require an extremely timely treatment and transfusion plays an irreplaceable role in the emergency treatment of such patients. An increasing number of evidence-based medicinal evidences and clinical practices suggest that patients with severe traumatic bleeding benefit from early transfusion of low-titer group O whole blood or hemostatic resuscitation with red blood cells, plasma and platelet of a balanced ratio. However, the current domestic mode of blood supply cannot fully meet the requirements of timely and effective blood transfusion for emergency treatment of patients with severe trauma in clinical practice. In order to solve the key problems in blood supply and blood transfusion strategies for emergency treatment of severe trauma, Branch of Clinical Transfusion Medicine of Chinese Medical Association, Group for Trauma Emergency Care and Multiple Injuries of Trauma Branch of Chinese Medical Association, Young Scholar Group of Disaster Medicine Branch of Chinese Medical Association organized domestic experts of blood transfusion medicine and trauma treatment to jointly formulate Chinese expert consensus on blood support mode and blood transfusion strategies for emergency treatment of severe trauma patients ( version 2024). Based on the evidence-based medical evidence and Delphi method of expert consultation and voting, 10 recommendations were put forward from two aspects of blood support mode and transfusion strategies, aiming to provide a reference for transfusion resuscitation in the emergency treatment of severe trauma and further improve the success rate of treatment of patients with severe trauma.

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 report the results of national surveillance on the distribution and antimicrobial resistance profile of clinical bacterial isolates from bloodstream infections in China in 2021.Methods:The clinical bacterial strains isolated from blood culture from member hospitals of Blood Bacterial Resistant Investigation Collaborative System (BRICS) were collected during January 2021 to December 2021. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical Laboratory Standards Institute (CLSI). WHONET 5.6 was used to analyze data.Results:During the study period, 11 013 bacterial strains were collected from 51 hospitals, of which 2 782 (25.3%) were Gram-positive bacteria and 8 231 (74.7%) were Gram-negative bacteria. The top 10 bacterial species were Escherichia coli (37.6%), Klebsiella pneumoniae (18.9%), Staphylococcus aureus (9.8%), coagulase-negative Staphylococci (6.3%), Pseudomonas aeruginosa (3.6%), Enterococcus faecium (3.6%), Acinetobacter baumannii (2.8%), Enterococcus faecalis (2.7%), Enterobacter cloacae (2.5%) and Klebsiella spp (2.1%). The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative Staphylococcus aureus were 25.3% and 76.8%, respectively. No glycopeptide- and daptomycin-resistant Staphylococci was detected; more than 95.0% of Staphylococcus aureus were sensitive to ceftobiprole. No vancomycin-resistant Enterococci strains were detected. The rates of extended spectrum B-lactamase (ESBL)-producing isolated in Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis were 49.6%, 25.5% and 39.0%, respectively. The prevalence rates of carbapenem-resistance in Escherichia coli and Klebsiella pneumoniae were 2.2% and 15.8%, respectively; 7.9% of carbapenem-resistant Klebsiella pneumoniae was resistant to ceftazidime/avibactam combination. Ceftobiprole demonstrated excellent activity against non-ESBL-producing Escherichia coli and Klebsiella pneumoniae. Aztreonam/avibactam was highly active against carbapenem-resistant Escherichia coli and Klebsiella pneumoniae. The prevalence rate of carbapenem-resistance in Acinetobacter baumannii was 60.0%, while polymyxin and tigecycline showed good activity against Acinetobacter baumannii (5.5% and 4.5%). The prevalence of carbapenem-resistance in Pseudomonas aeruginosa was 18.9%. Conclusions:The BRICS surveillance results in 2021 shows that the main pathogens of blood stream infection in China are gram-negative bacteria, in which Escherichia coli is the most common. The MRSA incidence shows a further decreasing trend in China and the overall prevalence of vancomycin-resistant Enterococci is low. The prevalence of Carbapenem-resistant Klebsiella pneumoniae is still on a high level, but the trend is downwards.

Femoral neck fracture (FNF) in the elderly patients is currently a major health challenge worldwide, with excessive consumption of medical resources, high incidence of complications as well as suboptimal outcome and prognosis. Hip joint arthroplasty (HJA) has been the mainstream treatment for FNF in the elderly, but the conventional surgical approaches and techniques are still confronted with a series of bottlenecks such as dislocation, limp and limb length discrepancy. In recent years, direct anterior approach (DAA) for HJA (DAA-HJA) has been a major new choice in the field of joint replacement, which achieves improved clinical effectiveness of HJA in the treatment of elderly FNF, due to the fact that DAA approach involves the neuromuscular interface and accords with the idea of soft tissue retention and enhanced recovery after surgery. However, there is still a lack of unified understanding of standard technique and procedure of DAA-HJA in the treatment of elderly FNF. Therefore, relevant experts from the Hip Joint Group of Chinese Orthopedics Association of Chinese Medical Association, Youth Arthrology Group of Orthopedic Committee of PLA, Orthopedic Committee of Chongqing Medical Association, Branch of Orthopedic Surgeons of Chongqing Medical Doctor Association and Sport Medicine Committee of Chongqing Medical Association were organized to formulate the " Chinese expert consensus on the technical standard of direct anterior hip arthroplasty for elderly femoral neck fracture ( version 2023)" based on evidence-based medicine. This consensus mainly proposed 13 recommendations covering indications, surgical plans, prosthesis selections, surgical techniques and processes, and postoperative management of DAA-HJA in elderly patients with FNF, aiming to promote standardized, systematic and patient-specific diagnosis and treatment to improve the functional prognosis of the patients.