Objective: To investigate factors influencing perioperative blood transfusion in patients with scarred uterus during pregnancy undergoing cesarean section, construct and validate a transfusion risk prediction model, and provide evidence for preoperative assessment and blood management. Methods: Clinical data of 405 patients undergoing cesarean section for scarred uterus during pregnancy at the First Affiliated Hospital of Xi'an Jiaotong University from January 2020 to December 2024 were retrospectively collected. The dataset was randomly divided into a training set (n=284) and a validation set (n=121) at a 7∶3 ratio. Within the training set, Firth-penalized logistic regression was employed for multivariate analysis to identify independent factors influencing perioperative blood transfusion and construct a predictive model. Model performance was evaluated in the validation set. Results: Multivariate Firth regression analysis showed that severe placenta previa (OR=75.566, 95%CI: 8.603-9979.174) and placenta accreta (OR=4.591, 95%CI: 1.120-19.416) were independent risk factors for perioperative blood transfusion, while preoperative red blood cell count (OR=0.189, 95%CI: 0.083-0.405) and fibrinogen levels (OR=0.588, 95%CI: 0.395-0.855) were protective factors. The predictive model constructed based on these four variables demonstrated good discriminatory performance, with areas under the receiver operating characteristic curves of 0.803 (95%CI: 0.740-0.867) and 0.753 (95%CI: 0.644-0.862) in the training and validation sets, respectively. Conclusion: For patients with scarred uterus during pregnancy undergoing cesarean section, severe placenta previa and placenta accreta significantly increase the risk of transfusion, while higher preoperative red blood cell count and fibrinogen levels exert a protective effect. The predictive model established in this study facilitates the identification of patients requiring transfusion, thereby enabling preoperative blood preparation and optimized blood management.

At present,the drug substitutes represented by new psychoactive substances are gradually be-coming popular,leading to an increasing demand for identifying novel drugs with unknown structures in drug investigation.Nuclear magnetic resonance(NMR)spectroscopy is an important tool for ana-lyzing molecular structures.In the absence of standard substances,quantitative NMR(qNMR)can un-dertake the quantitative analysis of target substances in complex mixtures and has unique advantages in the research of new drugs and their precursor drugs.Due to the limitations of the site and mainte-nance costs,as well as relatively complex operation,high-field superconducting NMR is less com-monly applied in drug research.The desktop low-field NMR developed in recent years provides a new alternative solution.Due to the use of permanent magnets,its size is reduced,and the operation and maintenance costs are lowered.It has been widely used in various research fields.This article reviews the development of low-field NMR technology,summarizes the application of desktop low-field NMR in screening and identification of suspicious substances,rapid content determination,analysis of drug manufacturing processes and synthetic routes,and correlation traceability.It also looks forward to the prospects and development directions of this technology in drug research,aiming to provide a reference for researchers who work in analytical chemistry and drug research.

Objective To understand the current situation of healthcare-associated infection(HAI)in China,pro-vide data support and decision-making basis for formulating scientific and effective strategies for HAI prevention and control.Methods A nationwide cross-sectional survey on HAI was conducted among various types and levels of medical institutions in China according to a unified protocol of bedside surveys and case investigations.Results In 2024,a total of 5 736 medical institutions and 2 751 765 patients were surveyed.Among them,34 889 HAI cases were identified,with a prevalence rate of 1.27％.The number of HAI episodes was 38 032,and case prevalence rate was 1.38％.The prevalence rate of HAI in medical institutions in different regions of China ranged from 0.66％to 2.35％.Among medical institutions of different scales,those with a bed capacity of ≥900 had the high-est incidence of HAI,reaching 1.65％.The most common infection site was the lower respiratory tract(44.66％),followed by the urinary tract(12.94％),surgical site(9.32％),upper respiratory tract(7.02％),and bloodstream infection(5.78％).The top 3 departments with the highest HAI rates were the general intensive care unit(10.02％),department of neurosurgery(5.51％),and department(group)of hematology(5.34％).A total of 23 238 strains of HAI pathogens were detected,with 10 714 strains(46.10％)from lower respiratory tract speci-mens.The top 5 detected strains were Klebsiella pneumoniae(14.76％),Pseudomonas aeruginosa(13.33％),Escherichia coli(12.79％),Acinetobacter baumannii(9.23％),and Staphylococcus aureus(7.88％).231 944 pa-tients underwent class Ⅰ incision surgery were monitored,with 1 647 cases experienced surgical site infection,and the prevalence rate of surgical site infection was 0.71％.The number of patients who should undergo pathogen de-tection(patients receiving therapeutic and therapeutic combined prophylactic antimicrobial agents)was 715 179,while the actual number was 480 492,with a pathogen detection rate of 67.18％.425 225 patients received patho-genic detection before treatment,with a detection rate of 59.46％.Conclusion The overall HAI prevalence in Chi-na is lower,showing disparities among medical institutions of different regions and scales.Therefore,precise imple-mentation of measures is necessary for HAI prevention and control,with a focus on high-risk institutions and high-risk departments,key areas,and critical procedures.All levels of medical institutions should continuously reduce the incidence of HAI by strengthening monitoring,standardizing the use of antimicrobial agents,and reinforcing basic HAI prevention and control measures.

Objective To understand the current situation of healthcare-associated infection(HAI)in China,pro-vide data support and decision-making basis for formulating scientific and effective strategies for HAI prevention and control.Methods A nationwide cross-sectional survey on HAI was conducted among various types and levels of medical institutions in China according to a unified protocol of bedside surveys and case investigations.Results In 2024,a total of 5 736 medical institutions and 2 751 765 patients were surveyed.Among them,34 889 HAI cases were identified,with a prevalence rate of 1.27％.The number of HAI episodes was 38 032,and case prevalence rate was 1.38％.The prevalence rate of HAI in medical institutions in different regions of China ranged from 0.66％to 2.35％.Among medical institutions of different scales,those with a bed capacity of ≥900 had the high-est incidence of HAI,reaching 1.65％.The most common infection site was the lower respiratory tract(44.66％),followed by the urinary tract(12.94％),surgical site(9.32％),upper respiratory tract(7.02％),and bloodstream infection(5.78％).The top 3 departments with the highest HAI rates were the general intensive care unit(10.02％),department of neurosurgery(5.51％),and department(group)of hematology(5.34％).A total of 23 238 strains of HAI pathogens were detected,with 10 714 strains(46.10％)from lower respiratory tract speci-mens.The top 5 detected strains were Klebsiella pneumoniae(14.76％),Pseudomonas aeruginosa(13.33％),Escherichia coli(12.79％),Acinetobacter baumannii(9.23％),and Staphylococcus aureus(7.88％).231 944 pa-tients underwent class Ⅰ incision surgery were monitored,with 1 647 cases experienced surgical site infection,and the prevalence rate of surgical site infection was 0.71％.The number of patients who should undergo pathogen de-tection(patients receiving therapeutic and therapeutic combined prophylactic antimicrobial agents)was 715 179,while the actual number was 480 492,with a pathogen detection rate of 67.18％.425 225 patients received patho-genic detection before treatment,with a detection rate of 59.46％.Conclusion The overall HAI prevalence in Chi-na is lower,showing disparities among medical institutions of different regions and scales.Therefore,precise imple-mentation of measures is necessary for HAI prevention and control,with a focus on high-risk institutions and high-risk departments,key areas,and critical procedures.All levels of medical institutions should continuously reduce the incidence of HAI by strengthening monitoring,standardizing the use of antimicrobial agents,and reinforcing basic HAI prevention and control measures.

Objective:To investigate the etiology,diagnosis and treatment of 45,X/46,XY mixed gonadal dysgenesis and the patients'clinical characteristics of conception,pregnancy and delivery,with purpose of improving the treatment and pregnancy manage-ment of the patients.Methods:We retrospectively analyzed the clinical data on a pregnant patient with45,X/46,XY mixed gonadal dysgenesis.Results:Based on the findings of hypoplasia of secondary sexual characteristics,streak gonads,chromosome karyotype incompatibility with social sex,and chromosome aberration in the gonadal tissue,the patient was diagnosed with 45,X/46,XY mixed gonadal dysgenesis,received oocyte donation and intracytoplasmic sperm injection-embryo transfer(ICSI-ET),and achieved a live birth.Conclusion:Female patients with 45,X/46,XY mixed gonadal dysgenesis are infertile,but can achieve pregnancy through o-ocyte donation.However,the incidence rates of pregnancy complications and abnormal delivery are higher in these patients than in nor-mal females.The perinatal outcomes can be improved by efficient treatment and pregnancy management of the patients.

Sucrose synthase plays a crucial role in the plant sugar metabolism pathway by catalyzing the production of uridine diphosphate (UDP)-glucose, which serves as a bioactive glycosyl donor for various metabolic processes. In this study, a sucrose synthase gene named CtSus was cloned from Cistanche tubulosa, a traditional Chinese medicine known for its rich content of diverse glycosides, based on transcriptome analysis results. The open reading frame of CtSus was 2 418 bp long encoding 805 amino acids. Sequence analysis revealed conserved domains associated with the plant sucrose synthase family at both the N-terminal and C-terminal regions of CtSus protein. Phylogenetic analysis demonstrated that CtSus shares a close evolutionary relationship with sucrose synthases from other plants within the same order. Functional identification of CtSus was performed through whole-cell catalysis coupling with UGT71BD1, a characterized glycosyltransferase enzyme. The results showed that the introduction of CtSus significantly enhanced the conversion rate of glycosylation catalyzed by UGT71BD1. The soluble expression of CtSus in Escherichia coli was further achieved using the pCold^TM TF expression vector. In vitro enzymatic assay indicated the activity of CtSus to catalyze the formation of UDP-glucose in the presence of sucrose and UDP. Real-time quantitative-polymerase chain reaction results showed that the expression patterns of CtSus gene in different parts of C. tubulosa and the suspension cell cultures of C. tubulosa under drought stress correlated with the accumulation patterns observed for phenylethanol glycosides, respectively. Furthermore, key amino acids and their interactions between enzyme and substrate were explored based on protein structure prediction and molecular docking results. Overall, our findings identify a sucrose synthase CtSus responsible for the supply of the active glycosyl donor UDP-glucose during the biosynthesis of glycoside products in C. tubulosa and have also provided a gene element that can be utilized in engineering strain construction for glycoside products production.

OBJECTIVE To investigate the inhibitory effect and mechanism of 5,6-dimethylxanthe-none-4-acetic acid(DMXAA)on metastasis of Lewis lung cancer(LLC)in mice.METHODS The inhibi-tory effect of DMXAA on tumor metastasis was analyzed via an LLC xenograft tumor model and LLC metastatic tumor model.The mice of LLC xenograft tumor model were randomly divided into three groups:model group(physiological saline containing 1%DMSO,ip,once every two days),model+suni-tinib group(30 mg·kg-1,ip,once every two days),and model+DMXAA group(25 mg·kg-1,ip,once).Tumor volume and body mass were measured once every two days after administration.Two and five days after administration,tumor mass was measured by sacrificing the mice,followed by immunofluores-cence staining of tumor tissues.Platelet/endothelial cell adhesion molecule-1(CD31)and α-smooth muscle actin(α-SMA)were used to analyze the vascular structure of tumor tissues.The tumor hypoxia level was detected using the hypoxia probe pimonidazole staining.The mice of LLC metastatic tumor model were randomly divided into three groups:model group(physiological saline containing 1%DMSO,ip,twice a week),model+sunitinib group(60 mg·kg-1,ip,twice a week),and model+DMXAA group(25 mg·kg-1,ip,once).At the Two and five weeks after administration,the in vivo tumor growth and metastasis were observed and quantified using a small animal live imaging system.RESULTS Compared with the model group,the tumor volume and mass of the model+sunitinib group and model+ DMXAA group were significantly reduced(P<0.05,P<0.01),and DMXAA took effect faster and more significantly than sunitinib.At the same time,compared with the model group,the body mass in the model+sunitinib group decreased significantly(P<0.05),but there was no significant difference in body mass the model+DMXAA group.Compared with the model group,model+sunitinib had no effect on tumor metastasis,but model+DMXAA significantly reduced tumor metastasis two weeks after administration(P<0.01).Compared with the model group,the coverage rate of α-SMA/CD31 in the model+sunitinib group and model+DMXAA group increased significantly(P<0.05).Compared with the model group,there was no significant change in the tumor hypoxia area in the model+sunitinib group,but this in the model+DMXAA group decreased significantly(P<0.01).CONCLUSION DMXAA significantly inhibits the growth and metastasis of LLC in mice,and its mechanism may be related to its improvement of tumor vascular normalization and hyposic microenvironments.

Objective To investigate the attributable risk(AR)of Acinetobacter baumannii(AB)infection in criti-cally ill patients.Methods A multicenter retrospective cohort study was conducted among adult patients in inten-sive care unit(ICU).Patients with AB isolated from sterile body fluid and confirmed with AB infection in each cen-ter were selected as the infected group.According to the matching criteria that patients should be from the same pe-riod,in the same ICU,as well as with similar APACHE Ⅱ score(±5 points)and primary diagnosis,patients who did not infect with AB were selected as the non-infected group in a 1:2 ratio.The AR was calculated.Results The in-hospital mortality of patients with AB infection in sterile body fluid was 33.3％,and that of non-infected group was 23.1％,with no statistically significant difference between the two groups(P=0.069).The AR was 10.2％(95％CI:-2.3％-22.8％).There is no statistically significant difference in mortality between non-infected pa-tients and infected patients from whose blood,cerebrospinal fluid and other specimen sources AB were isolated(P＞0.05).After infected with AB,critically ill patients with the major diagnosis of pulmonary infection had the high-est AR.There was no statistically significant difference in mortality between patients in the infected and non-infec-ted groups(P＞0.05),or between other diagnostic classifications.Conclusion The prognosis of AB infection in critically ill patients is highly overestimated,but active healthcare-associated infection control for AB in the ICU should still be carried out.

Objective To study the role of sphingosine-1-phosphate(S1P)signal on the proliferation of breast cancer BT549 cells.Methods Cells were divided into control group and experimental group,experimental group were treated with 0.1,1.0,10.0 μmol·L-1 S1P receptor agonist SEW2871 for 72 h.Control group was cultured with 0.1％fetal bovine serum.Cell proliferation was detected by methyl thiazolyl tetrazolium(MTT)assay.Cell models of overexpressing S1P receptors in BT549 were divided into three groups:blank plasmid group(LUC),wild type S1P receptor overexpression group(WT),S1P receptor phosphorylation site mutation overexpression group(MUT);the proliferation ratio was detected by MTT,the number of cell clones was counted by colony formation experiment.S1P antagonist W146(10 μmol·L-1)and protein kinase(AKT)signaling inhibitor MK2206(90 nmol·L-1)were used to detect the role of S1P signaling in the proliferation of breast cancer cells.The expression of phosphorylate signal transducer and activator of transcription 3(p-STAT3),c-Myc proteins were detected by Western blot.Results The growth ratio of BT549 cells in control group and 0.1,1.0,10.0 μmol·L-1experimental groups were 1.00±0.03,1.13±0.06,1.06±0.10 and 1.07±0.03,0.1 μmol·L-1 SEW2871 promot the cell proliferation(P＜0.05).Compared between WT group,MUT group and LUC group,the growth rate and the number of clonal colonies were increased after overexpression of S1P receptor(all P＜0.05).The growth ratio of BT549 cells after treatment with W146 and MK2206 in the LUC group,WT group and MUT group were 1.25±0.12,1.31±0.03,1.43±0.14 and 0.87±0.15,0.77±0.03,0.88±0.02.Compared between MUT group,WT group and corresponding DMSO group,the differences were statistically significant(all P＜0.01).The number of cell clony formation number after treatment with W146 were 65.65±5.12,141.48±5.63 and 93.64±5.14;compared between MUT,WT group and corresponding DMSO group,the differences were statistically significant(all P＜0.05).The relative protein expression levels of p-STAT3 in LUC group,WT group and MUT group were 0.67±0.04,0.69±0.08 and 0.81±0.06,the relative protein expression levels of proto-oncogene c-Myc were 1.69±0.03,0.70±0.10 and 0.67±0.07,compared between WT group,MUT group and corresponding DMSO group,the difference was statistically significant(P＜0.05).Conclusion S1P signaling can promote proliferation in breast cancer BT549 cells,and the mechanism could be related to AKT and STAT3 signaling pathway.