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 investigate the effects of estrogen signaling on T-cell recruitment and polarization in acutely injured skeletal muscle.Methods One hundred C57BL/6 male mice,one hundred and eighty C57BL/6 female mice were selected.Twenty-five female mice were ovariectomized(OVX)and 10 male mice were taken as the sham-operated(sham).Then,cardiotoxin(CTX)induced tibialis anterior(TA)injury for preparing mice myoinjury model.Subcutaneous injection of 17β-estradiol(E2)or estrogen receptor antagonist 4-hydroxytamoxifen(4-OHT)was performed.A total of 140 mice(70 males and 70 females)were divided into four group including:PBS-male,CTX-male,PBS-female,and CTX-female.Serum estradiol(E2)levels were measured by ELISA,and muscle injury models were validated via HE staining.Subsequently,20 male and 20 female mice were selected for immunofluorescence(IF)and Real-time PCR to assess estrogen receptors(ER)expression in injured muscle tissue.Further,10 male and 40 female mice were allocated into five experimental groups,including CTX,CTX+E2,CTX+4-OHT,CTX+OVX,CTX+sham.HE staining and IF were performed to evaluate inflammatory infiltration in the injured muscle.Additionally,50 female mice were divided into CTX and CTX+OVX groups,and IF combined with flow cytometry were used to analyze T-cell phenotypes and muscle fiber regeneration in the injured muscle.Results In vivo,serum E2 and myofiber ERβ increased post-injury in mice of both sexes,significantly higher in females.Compared to the control group,E2 alleviated inflammation,OVX exacerbated inflammation,increased CD4+T-cell infiltration,elevated T helper 1 cell(Th1)response,decreased regulatory T cells(Tregs),impaired regeneration.In vitro,IFN-γ/LPS significantly upregulated ERβ in myotubes.Conclusion Estrogen signaling critically regulates muscle inflammation.Estrogen deficiency(OVX)delays repair of skeletal muscle by promoting Th1 response and suppressing Tregs function.

Objective To investigate the effects of exercise and complex environment on lipopolysaccharide(LPS)-induced dopaminergic neuron death in the substantia nigra of midbrain.Methods C57BL/6 mice were divided into control group,LPS group,LPS+swimming group and LPS+complex environment group,with 7 mice in each group.The mice in the LPS group were injected with LPS into the brain to establish an inflammatory model of Parkinson's disease and lived in cages for 2 weeks.Mice in LPS+swimming group were forced to swim for 15 minutes every day for 2 weeks after modeling.The mice in the LPS+complex environment group were placed in a complex environment for 2 weeks after modeling.The control group mice were not treated.After 14 days of modeling,behavioral experiments such as footprint,open field and rotating rod were performed on each group of mice to detect the autonomous exercise ability,exercise balance ability and depression level of mice.The expressions of tyrosine hydroxylase(TH)in substantia nigra was detected by immunohistochemical staining and Western blotting.The expressions of brain-derived neurotrophic factor(BDNF),Caspase-3,interleukin-1β(IL-1β),interleukin-6(IL-6)and tumor necrosis factor-α(TNF-α)in the substantia nigra of the midbrain were detected by Western blotting.The transcription levels of IL-1β,IL-6 and TNF-α in substantia nigra were detected by RT-PCR.Results Compared with the control group,the exercise ability and balance ability of mice in LPS group,LPS+swimming group and LPS+complex environment group decreased,the depression level increased(P＜0.001),the number of TH positive neurons and BDNF protein decreased significantly(P＜0.001),and the contents of Caspase-3,IL-1β,IL-6 and TNF-α increased significantly(P＜0.001).Compared with the LPS group,the exercise ability and balance ability of the mice in the LPS+swimming group and the LPS+complex environment group were restored,the depression level decreased significantly(P＜0.01),the survival number of TH positive neurons and the content of BDNF increased significantly(P＜0.01),Caspase-3,IL-1β,IL-6 and TNF-α reduced significantly(P＜0.01),and the phenomenon in the LPS+complex environment group was more significant.Conclusion Exercise and complex environment can inhibit LPS-induced central nervous system inflammation in mice,thereby reducing damage to midbrain substantia nigra neurons,and the inhibitory effect of LPS+complex environment group is more significant.

Objective To provide anatomical,radiological,and clinical diagnostic and therapeutic references for ankylosing spondylitis and spinal surgical operations.Methods Non-measurement spinal observations,X-ray examinations,and measurements were performed on two spinal specimens,along with digital image acquisition and processing.Results The first specimen included thoracic vertebra 7(T7)to lumbar vertebra 3(L3),with an average total length of 29.7 cm;the second specimen ranged from cervical vertebra 7(C7)to lumbar vertebra 2(L2),with an average total length of 38.3 cm.The specimens showed partial or complete calcification of ligaments,ossification of the small joints and intervertebral discs,and osteoporosis;The anterior-posterior diameter(width)of the vertebral foramen was narrower than that of a normal adult,while most of the superior-inferior diameter(height)was wider.Radiographically,the anterior longitudinal ligament calcification appeared as dot-like or striated,but it was actually flaky in the actual specimens.The specimens provided views of the facet joints,costovertebral joints,and intervertebral foramina that was difficult to demonstrate on two-dimensional X-ray images.Conclusion As ankylosing spondylitis progresses,the range of motion in spinal bending and rotation decreases,as does the extent of thoracic expansion,thereby affecting respiration and complicating procedures such as intraspinal anesthesia and sacral canal injections.In terms of diagnosis,bone specimens and X-ray films allow us to understand the development process and severity of ankylosing spondylitis more directly and accurately.

Objective:To analyze the risk factors for late-onset hemorrhagic cystitis(LOHC)after allogeneic hematopoietic stem cell transplantation(allo-HSCT),the risk factors for the progression of LOHC to severe LOHC,and the effect of LOHC on survival.Methods:The clinical data of 300 patients who underwent allo-HSCT at the First Affiliated Hospital of Chongqing Medical University from January 2015 to December 2021 were retrospectively analyzed.The relevant clinical parameters that may affect the occurance of LOHC after allo-HSCT were selected for univariate and multivariate analysis.Then,the differences in overall survival(OS)and progression-free survival(PFS)between different groups were analyzed.Results:The results of multivariate analysis showed that the independent risk factors for LOHC after allo-HSCT were as follows:age≤45 years old(P=0.039),intensified conditioning regimen with fludarabine/cladribine and cytarabine(P=0.002),albumin ≤ 30 g/L on d30 after transplantation(P=0.007),CMV-DNA positive(P=0.028),fungal infection before transplantation(P=0.026),and the occurrence of grade Ⅱ-Ⅳ aGVHD(P=0.006).In the transplant patients who have already developed LOHC,the occurance of LOHC within 32 days after transplantation(P=0.008)and albumin ≤ 30 g/L on d30 after transplantation(P=0.032)were independent risk factors for the progression to severe LOHC.The OS rate of patients with severe LOHC was significantly lower than that of patients without LOHC(P=0.041).Conclusion:For the patients aged ≤ 45 years old and with intensified conditioning regimen,it is necessary to be vigilant about the occurrence of LOHC;For the patients with earlier occurrence of LOHC,it is necessary to be vigilant that it develops into severe LOHC.Early prevention and treatment of LOHC are essential.Regular monitoring of CMV-DNA and albumin levels,highly effective antiviral and antifungal therapies,and prevention of aGVHD are effective measures to prevent the occurrence and development of LOHC.

Objective:To analyze the risk factors of primary poor graft function (PGF) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients with myeloid malignancies and the impact of primary PGF on survival. Methods:The clinical data of 146 patients with myeloid malignancies who underwent allo-HSCT in our hospital from January 2015 to December 2021 were retrospectively studied. Some relevant clinical parameters which may affect the development of primary PGF after allo-HSCT were selected for univariate and multivariate analysis,as well as performed survival analysis. Results:A total of 9 patients (6.16％) were diagnosed with primary PGF,and their medium age was 37(28-53) years old. Among them,1 case underwent matched sibling donor HSCT,1 case underwent matched unrelated donor HSCT,and 7 cases underwent HLA-haploidentical related donor HSCT. Moreover,5 cases were diagnosed as cytomegalovirus (CMV) infection,and 3 cases as Epstein-Barr virus (EBV) infection. Univariate and multivariate analysis showed that CD34+cell dose<5×106/kg and pre-transplant C-reactive protein (CRP)>10 mg/L were independent risk factors for occurrence of the primary PGF after allo-HSCT in patients with myeloid malignancies. The 3-year overall survival (OS) rate of primary PGF group was 52.5％,which was significantly lower than 82.8％ of good graft function group (P<0.05). Conclusion:Making sure pre-transplant CRP≤10 mg/L and CD34+cell dose ≥5×106/kg in the graft may have an effect on preventing the occurrence of primary PGF after allo-HSCT. The occurrence of primary PGF may affect the OS rate of transplant patients,and early prevention and treatment are required.

Objective To investigate the expression and prognostic value of spindle and kinetochore-associated complex subunit 2(SKA2)in cervical cancer tissues,as well as its impact on the proliferation,migration and invasion of cervical cancer cells.Methods The expression of SKA2 in cervical cancer tissues was analyzed by bioinformatics database and immunohistochemical SP method,and the relationship between SKA2 expression level and clinicopathological features of cervical cancer patients and its prognostic value was analyzed.The mRNA expression of SKA2 in human normal cervical cells(HcerEpic)and cervical cancer cells(HeLa,SiHa,CaSki,C-33A)was detected by RT-qPCR.Cervical cancer cells SiHa with higher SKA2 expression level was selected for further study.SiHa cell model with down-regulated SKA2 expression was constructed,and its knockdown effect was verified.Cell proliferation capacity was detected by CCK-8 method,cell migration capacity was detected by cell scratch wound healing assay,and cell migration and invasion capacity was detected by Transwell assay.Results Compared with normal cervical tissues and cells,the expression levels of SKA2 mRNA and protein were higher in cervical cancer tissues and cells,and the differences were statistically significant(P<0.05).High SKA2 expression was associated with FIGO staging in patients with cervical cancer.Furthermore,SKA2 knockdown could inhibit the proliferation,migration and invasion of SiHa cells in cervical cancer(P<0.05).Conclusion SKA2 is up-regulated in cervical cancer tissues and cells,and can promote the proliferation,migration and invasion of cervical cancer cells.The expression level of SKA2 is associated with the progression of cervical cancer,and the prognosis of cervical cancer patients with high SKA2 expression is worse.

Objective To investigate the distribution and antimicrobial resistance profiles of the common pathogens isolated from urine from 2015 to 2021 in the CHINET Antimicrobial Resistance Surveillance Program.Methods The bacterial strains were isolated from urine and identified routinely in 51 hospitals across China in the CHINET Antimicrobial Resistance Surveillance Program from 2015 to 2021.Antimicrobial susceptibility was determined by Kirby-Bauer method,automatic microbiological analysis system and E-test according to the unified protocol.Results A total of 261 893 nonduplicate strains were isolated from urine specimen from 2015 to 2021,of which gram-positive bacteria accounted for 23.8％(62 219/261 893),and gram-negative bacteria 76.2％(199 674/261 893).The most common species were E.coli(46.7％),E.faecium(10.4％),K.pneumoniae(9.8％),E.faecalis(8.7％),P.mirabilis(3.5％),P.aeruginosa(3.4％),SS.agalactiae(2.6％),and E.cloacae(2.1％).The strains were more frequently isolated from inpatients versus outpatients and emergency patients,from females versus males,and from adults versus children.The prevalence of ESBLs-producing strains in E.coli,K.pneumoniae and P.mirabilis was 53.2％,52.8％and 37.0％,respectively.The prevalence of carbapenem-resistant strains in E.coli,K.pneumoniae,P.aeruginosa and A.baumannii was 1.7％,18.5％,16.4％,and 40.3％,respectively.Lower than 10％of the E.faecalis isolates were resistant to ampicillin,nitrofurantoin,linezolid,vancomycin,teicoplanin and fosfomycin.More than 90％of the E.faecium isolates were ressitant to ampicillin,levofloxacin and erythromycin.The percentage of strains resistant to vancomycin,linezolid or teicoplanin was＜2％.The E.coli,K.pneumoniae,P.aeruginosa and A.baumannii strains isolated from ICU inpatients showed significantly higher resistance rates than the corresponding strains isolated from outpatients and non-ICU inpatients.Conclusions E.coli,Enterococcus and K.pneumoniae are the most common pathogens in urinary tract infection.The bacterial species and antimicrobial resistance of urinary isolates vary with different populations.More attention should be paid to antimicrobial resistance surveillance and reduce the irrational use of antimicrobial agents.

Objective To understand the distribution and changing resistance profiles of clinical isolates of Enterococcus in hospitals across China from 2015 to 2021.Methods Antimicrobial susceptibility testing was conducted for the clinical isolates of Enterococcus according to the unified protocol of CHINET program by automated systems,Kirby-Bauer method,or E-test strip.The results were interpreted according to the Clinical & Laboratory Standards Institute(CLSI)breakpoints in 2021.WHONET 5.6 software was used for statistical analysis.Results A total of 124 565 strains of Enterococcus were isolated during the 7-year period,mainly including Enterococcus faecalis(50.7％)and Enterococcus faecalis(41.5％).The strains were mainly isolated from urinary tract specimens(46.9％±2.6％),and primarily from the patients in the department of internal medicine,surgery and ICU.E.faecium and E.faecalis strains showed low level resistance rate to vancomycin,teicoplanin and linezolid(≤3.6％).The prevalence of vancomycin-resistant E.faecalis and E.faecium was 0.1％and 1.3％,respectively.The prevalence of linezolid-resistant E.faecalis increased from 0.7％in 2015 to 3.4％in 2021,while the prevalence of linezolid-resistant E.faecium was 0.3％.Conclusions The clinical isolates of Enterococcus were still highly susceptible to vancomycin,teicoplanin,and linezolid,evidenced by a low resistance rate.However,the prevalence of linezolid-resistant E.faecalis was increasing during the 7-year period.It is necessary to strengthen antimicrobial resistance surveillance to effectively identify the emergence of antibiotic-resistant bacteria and curb the spread of resistant pathogens.

Objective To examine the changing antimicrobial resistance profile of Enterobacter spp.isolates in 53 hospitals across China from 2015 t0 2021.Methods The clinical isolates of Enterobacter spp.were collected from 53 hospitals across China during 2015-2021 and tested for antimicrobial susceptibility using Kirby-Bauer method or automated testing systems according to the CHINET unified protocol.The results were interpreted according to the breakpoints issued by the Clinical & Laboratory Standards Institute(CLSI)in 2021(M100 31st edition)and analyzed with WHONET 5.6 software.Results A total of 37 966 Enterobacter strains were isolated from 2015 to 2021.The proportion of Enterobacter isolates among all clinical isolates showed a fluctuating trend over the 7-year period,overall 2.5％in all clinical isolates amd 5.7％in Enterobacterale strains.The most frequently isolated Enterobacter species was Enterobacter cloacae,accounting for 93.7％(35 571/37 966).The strains were mainly isolated from respiratory specimens(44.4±4.6)％,followed by secretions/pus(16.4±2.3)％and urine(16.0±0.9)％.The strains from respiratory samples decreased slightly,while those from sterile body fluids increased over the 7-year period.The Enterobacter strains were mainly isolated from inpatients(92.9％),and only(7.1±0.8)％of the strains were isolated from outpatients and emergency patients.The patients in surgical wards contributed the highest number of isolates(24.4±2.9)％compared to the inpatients in any other departement.Overall,≤ 7.9％of the E.cloacae strains were resistant to amikacin,tigecycline,polymyxin B,imipenem or meropenem,while ≤5.6％of the Enterobacter asburiae strains were resistant to these antimicrobial agents.E.asburiae showed higher resistance rate to polymyxin B than E.cloacae(19.7％vs 3.9％).Overall,≤8.1％of the Enterobacter gergoviae strains were resistant to tigecycline,amikacin,meropenem,or imipenem,while 10.5％of these strains were resistant to polycolistin B.The overall prevalence of carbapenem-resistant Enterobacter was 10.0％over the 7-year period,but showing an upward trend.The resistance profiles of Enterobacter isolates varied with the department from which they were isolated and whether the patient is an adult or a child.The prevalence of carbapenem-resistant E.cloacae was the highest in the E.cloacae isolates from ICU patients.Conclusions The results of the CHINET Antimicrobial Resistance Surveillance Program indicate that the proportion of Enterobacter strains in all clinical isolates fluctuates slightly over the 7-year period from 2015 to 2021.The Enterobacter strains showed increasing resistance to multiple antimicrobial drugs,especially carbapenems over the 7-year period.