ObjectiveThis study aimed to develop a novel method for encapsulating oocytes in sodium alginate hydrogel using microfluidics, then to vitrify these encapsulated oocytes in a single-step process with low concentrations of cryoprotectants. MethodsWe utilized a flow-focusing microfluidic chip to generate sodium alginate hydrogel microspheres. The influence of various parameters, including throat structure, cross-linking method, sodium alginate concentrations, and flow rate ratios on the stability diameter, and coefficient of variation of microspheres were examined. To further investigate the cold-resistance of these microspheres, we used cryomicroscopy to observe changes in volume and morphology of microspheres during cooling and warming processes. We used microfluidic chip to encapsulate oocytes in sodium alginate hydrogel microspheres, the empty rate of microspheres and loss rate of oocytes were determined. After releasing from microspheres and parthenogenetic activation with cytochalasin B and strontium chloride, the survival, cleavage and blastocyst rates were evaluated during in vitro maturation. Finally, oocytes encapsulated in sodium alginate microspheres were vitrified with low concentrations of cryoprotectants. We compared the survival and development capability of the oocytes with the Cryotop method. ResultsWhen the throat of the microfluidic chip measures 300 μm in length and 120 μm in width, microspheres can be uniformly formed at the throat of the chip. Sodium alginate generates microspheres with a wide size distribution when cross-linking outside the chip, while internal cross-linking within the chip results in more uniform microspheres. The stability of microsphere formation is significantly improved with the use of a three-channel internal cross-linking chip. At a flow rate of 2 μl/min and with 1% sodium alginate, the microfluidic chip can consistently and uniformly produce microspheres. Under flow rate ratios of 10, 15, and 20, the average microsphere diameters are 262.71 μm, 193.63 μm, and 156.63 μm, respectively. The sodium alginate hydrogel microspheres maintained their volume and structural integrity during the cooling and warming processes. Using a three-channel internal cross-linking microfluidic chip to encapsulate oocytes, at a flow rate ratio of 10, the empty rate is 32.28%, and the cell loss rate is 11.09%. After encapsulation and subsequent release, the oocyte survival rate (96.99%), cleavage rate (88.71%), and blastocyst formation rate (26.29%) showed no significant differences compared to the fresh group. After the microspheres were vitrified using a low concentration of cryoprotectant (10% DMSO+10% ehylene glycol (EG)+0.5 mol/L trehalose), the survival rate, cleavage rate, and blastocyst rate were 92.48%, 70.80%, and 20.42%, respectively. No significant difference was observed when compared to the Cryotop method using a higher concentration of cryoprotectant solution (15% DMSO+15% EG+0.5 mol/L trehalose). ConclusionWe designed and fabricated a microfluidic system with three-channel internal cross-linking chips used for oocyte vitrification preservation. The microfluidic system can generate oocytes-loaded sodium alginate hydrogel microspheres with uniform size, low empty rate, and good cold-resistance. The method successfully reduced the concentration of cryoprotectants in a single-step vitrification process, the developmental capability of oocytes during in vitro maturation were comparable with Cryotop method. Unlike the Cryotop method, the oocytes encapsulated in hydrogel does not come into contact with liquid nitrogen, eliminating the risk of cross-contamination. This study provides a novel approach to oocyte vitrification.

Helicobacter pylori(Hp)is responsible for chronic gastritis,peptic ulcers,and even gastric cancers.Currently,there is no vaccine to prevent or treat Hp infections.Here,we described the chemical synthesis of α-1,6-glucans with different lengths(di-to hexasaccharide),which are present in the core oligosaccharide of Hp lipopolysaccharide(LPS).The 1,2-cis-glucosidic bonds were constructed successfully using a synergistic glycosylation strategy based on acyl remote participation and solvent effects.The results of glycan microarrays indicated that all synthesized α-1,6-glucan fragments possessed a strong binding to IgG antibodies in both rabbit serum immunized with Hp O1 LPS and patient serum infected with Hp.The α-1,6-linked trisaccharide exhibited strong binding affinity to anti-LPS rabbit IgG antibodies.The α-1,6-glucan trisaccharide and pentasaccharide elicited a strong response to IgG antibodies in sera of most Hp-infected patients.Some patients'sera exhibited strong binding activity with α-1,6-linked disaccharide.The results suggest that the α-1,6-glucan disaccharide,trisaccharide and pentasaccharide could be important carbohydrate antigen fragments in Hp lipopolysaccharide.

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 understand the respiratory protection competency of staff in hospitals.Methods Staff from six hospitals of different levels and characteristics in Beijing were selected,including doctors,nurses,medical technicians,and servicers,to conduct knowledge assessment on respiratory protection competency.According to exposure risks of respiratory infectious diseases,based on actual cases and daily work scenarios,content of respira-tory protection competency assessment was designed from three aspects:identification of respiratory infectious di-seases,transmission routes and corresponding protection requirements,as well as correct selection and use of masks.The assessment included 6,6,and 8 knowledge points respectively,with 20 knowledge points in total,all of which were choice questions.For multiple-choice questions,full marks,partial marks,and no mark were given respective-ly if all options were correct,partial options were correct and without incorrect options,and partial options were correct but with incorrect options.Difficulty and discrimination analyses on question of each knowledge point was conducted based on classical test theory.Results The respiratory protection competency knowledge assessment for 326 staff members at different risk levels in 6 hospitals showed that concerning the 20 knowledge points,more than 60％participants got full marks for 6 points,while the proportion of full marks for other questions was relatively low.Less than 10％participants got full marks for the following 5 knowledge points:types of airborne diseases,types of droplet-borne diseases,conventional measures for the prevention and control of healthcare-associated infec-tion with respiratory infectious diseases,indications for wearing respirators,and indications for wearing medical protective masks.Among the 20 knowledge questions,5,1,and 14 questions were relatively easy,medium,and difficult,respectively;6,1,4,and 9 questions were with discrimination levels of ≥0.4,0.30-0.39,0.20-0.29,and ≤0.19,respectively.Conclusion There is still much room for hospital staff to improve their respiratory protection competency,especially in the recognition of diseases with different transmission routes and the indications for wearing different types of masks.

Objective To clarify the high-touch surface in oral diagnosis and treatment procedures,provide basis and guidance for cleaning and disinfection.Methods The direct observation method was used to investigate the tou-ch time and frequency of environmental surfaces in 7 outpatient departments of a tertiary stomatology hospitals in Beijing.The average touch frequency,95％confidence interval and cumulative touch rate were calculated.Results In oral diagnosis and treatment procedures,the average touch frequency of the environmental surface was 26.75 times per procedure,with the highest in endodontics(46.25 times per procedure)and the lowest in the oral mucosal specialty(10.19 times per procedure).The high-touch surface consisted of the shadowless lamp handle,manipula-tion panel and handle on dental unit(doctor's side),computer keyboard and mouse,handle and line front end of three way syringe,as well as dental high speed handpiece and line front end,with average touch frequencies of 3.99,3.85,2.65,1.86,and 1.40 times per procedure.The high-touch surface in all stomatology specialties in-cluded the manipulation panel and handle on dental unit(doctor's side),75％of specialties included computer key-board and mouse,and the shadowless lamp handle has the highest touch frequency in 50％of specialties.The ave-rage touch frequency of the environmental surface was highest(113.50 times per procedure)during crown prepara-tion procedure,and the lowest(8.50 times per procedure)during the orthodontic consultations.Conclusion The high-touch surface of different dental specialties and different diagnosis and treatment procedures are different.Me-dical institutions should take corresponding cleaning,disinfection and management measures according to the actual situation of high-touch surface in stomatology departments,so as to effectively improve the quality of environmental cleaning and disinfection.

Eleven compounds were isolated and purified from the ethyl acetate part of 80% ethanol extract of Ferula feruloides root by a combination of normal-phase silica gel column chromatography, Sephadex LH-20 dextran gel column chromatography and semi-preparative liquid chromatography and then modern wave spectrometry methods (NMR, MS, UV, IR) were used to identify the structures of the compounds, which were identified as baigene D (1), baigene E (2), baigene F (3), β-kirialovin (4), α-kirialovin (5), falcarindiol (6), ammoresinol (7), dshamirone (8), 2,3-dihydro-7-hydroxy-2S*,3R*-dimethyl-3-[4-methyl-5-(4-methy1-2-furyl)-3(E)-pentenyl]-furo[3,2-c]coumarin (9), 2,3-dihydro-7-hydroxy-2S*,3R*-dimethyl-2-[4,8-dimethyl-3(E),7-nonadi-enyl]-furo[3,2-c]coumarin (10), and baigene C (11). Compounds 1-3 are new coumarin analogues, and compounds 4-6 are firstly isolated from F. feruloides. The anti-proliferative activity of compounds 5, 7-11 against human gastric cancer (MKN-45) cells was evaluated using MTT assay, which showed that compounds 7-11 exhibited strong inhibitory activity, and compound 5 exhibited weak inhibitory activity.

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.

AIM:To investigate the effects and underlying mechanism of Toona sinensis bark extract(TAE)on the colon mucosal barrier and gut microbiota in mice with ulcerative colitis(UC)induced by dextran sulfate sodium(DSS).METHODS:Sixty C57BL/6J mice were randomly assigned to control,model,and mesalazine(0.2 g/kg)groups,as well as TAE groups(low,medium,and high-doses equal to crude drug concentrations of 2.3,4.6 and 9.2 g/kg,respectively).The UC model was induced by drinking of 2.5％DSS,and mean while the drugs were administered for 10 days.The mice were then evaluated in terms of weight,disease activity index(DAI),colon length,spleen index,and pathological changes in the colon tissues.In addition,the level of apoptosis in colon tissues was assessed by terminal de-oxynucleotidyl transferase dUTP nick-end labeling(TUNEL)fluorescence staining,and the expression of related proteins was evaluated by Western blot,levels of inflammatory factors were determined by enzyme-linked immunosorbent assays(ELISA),and the activities of total superoxide dismutase(T-SOD)and catalase(CAT)and malondialdehyde(MDA)content were assessed by biochemical assays.Furthermore,the constitution and diversity of the gut microbiota were inves-tigated by 16S rRNA gene sequencing.RESULTS:Compared with the control group,mice in the model group showed significantly reduced body weights(P<0.01),and the colon length was shortened significantly(P<0.05).Marked in-creases in the DAI and spleen index were observed(P<0.01),along with severe damage to the colon mucosa(P<0.01).Mechanistically,the level of intestinal epithelial cell apoptosis was significantly raised(P<0.01).The model group showed markedly reduced expression of occludin and claudin-1(P<0.01),the level of IL-10,and activities of T-SOD and CAT in the colon tissues(P<0.01).While the levels of IL-6,IL-1β,TNF-α,and the MDA content were increased signif-icantly(P<0.05).The abundance and diversity of the gut microbiota were decreased in the model group(P<0.05).Com-pared with the model group,all these indicators were ameliorated by the administration of TAE(P<0.05).The abundance of pathogenic bacteria,including Proteobacteria and Escherichia-Shigella,was decreased remarkably(P<0.05),while that of probiotics,including Bacteroidota and Muribaculaceae,were increased significantly(P<0.05).The abundance and diversity of the gut microbiota were increased.CONCLUSION:Taken together,Toona sinensis bark alcohol extract can alleviate damage to the intestinal mucosa by suppressing the apoptosis of intestinal epithelial cell,reducing the inflam-matory response,and mitigating oxidative stress.Treatment with TAE could also maintain the homeostasis of the gut micro-biota by regulating the abundance,ultimately meliorate the function of intestinal mucosal barrier.

Objective To investigate the clinical characteristics and prognosis of pneumococcal meningitis(PM),and drug sensitivity of Streptococcus pneumoniae(SP)isolates in Chinese children.Methods A retrospective analysis was conducted on clinical information,laboratory data,and microbiological data of 160 hospitalized children under 15 years old with PM from January 2019 to December 2020 in 33 tertiary hospitals across the country.Results Among the 160 children with PM,there were 103 males and 57 females.The age ranged from 15 days to 15 years,with 109 cases(68.1% )aged 3 months to under 3 years.SP strains were isolated from 95 cases(59.4% )in cerebrospinal fluid cultures and from 57 cases(35.6% )in blood cultures.The positive rates of SP detection by cerebrospinal fluid metagenomic next-generation sequencing and cerebrospinal fluid SP antigen testing were 40% (35/87)and 27% (21/78),respectively.Fifty-five cases(34.4% )had one or more risk factors for purulent meningitis,113 cases(70.6% )had one or more extra-cranial infectious foci,and 18 cases(11.3% )had underlying diseases.The most common clinical symptoms were fever(147 cases,91.9% ),followed by lethargy(98 cases,61.3% )and vomiting(61 cases,38.1% ).Sixty-nine cases(43.1% )experienced intracranial complications during hospitalization,with subdural effusion and/or empyema being the most common complication[43 cases(26.9% )],followed by hydrocephalus in 24 cases(15.0% ),brain abscess in 23 cases(14.4% ),and cerebral hemorrhage in 8 cases(5.0% ).Subdural effusion and/or empyema and hydrocephalus mainly occurred in children under 1 year old,with rates of 91% (39/43)and 83% (20/24),respectively.SP strains exhibited complete sensitivity to vancomycin(100% ,75/75),linezolid(100% ,56/56),and meropenem(100% ,6/6).High sensitivity rates were also observed for levofloxacin(81% ,22/27),moxifloxacin(82% ,14/17),rifampicin(96% ,25/26),and chloramphenicol(91% ,21/23).However,low sensitivity rates were found for penicillin(16% ,11/68)and clindamycin(6% ,1/17),and SP strains were completely resistant to erythromycin(100% ,31/31).The rates of discharge with cure and improvement were 22.5% (36/160)and 66.2% (106/160),respectively,while 18 cases(11.3% )had adverse outcomes.Conclusions Pediatric PM is more common in children aged 3 months to under 3 years.Intracranial complications are more frequently observed in children under 1 year old.Fever is the most common clinical manifestation of PM,and subdural effusion/emphysema and hydrocephalus are the most frequent complications.Non-culture detection methods for cerebrospinal fluid can improve pathogen detection rates.Adverse outcomes can be noted in more than 10% of PM cases.SP strains are high sensitivity to vancomycin,linezolid,meropenem,levofloxacin,moxifloxacin,rifampicin,and chloramphenicol.[Chinese Journal of Contemporary Pediatrics,2024,26(2):131-138]