OBJECTIVE: High-altitude hypoxia exposure often damages hippocampus-dependent learning and memory. Nogo-A is an important axonal growth inhibitory factor. However, its function in high-altitude hypoxia and its mechanism of action remain unclear. METHODS: In an in vivo study, a low-pressure oxygen chamber was used to simulate high-altitude hypoxia, and genetic or pharmacological intervention was used to block the Nogo-A/NgR1 signaling pathway. Contextual fear conditioning and Morris water maze behavioral tests were used to assess learning and memory in rats, and synaptic damage in the hippocampus and changes in oxidative stress levels were observed. In vitro, SH-SY5Y cells were used to assess oxidative stress and mitochondrial function with or without Nogo-A knockdown in Oxygen Glucose-Deprivation/Reperfusion (OGD/R) models. RESULTS: Exposure to acute high-altitude hypoxia for 3 or 7 days impaired learning and memory in rats, triggered oxidative stress in the hippocampal tissue, and reduced the dendritic spine density of hippocampal neurons. Blocking the Nogo-A/NgR1 pathway ameliorated oxidative stress, synaptic damage, and the learning and memory impairment induced by high-altitude exposure. CONCLUSION: Our results demonstrate the detrimental role of Nogo-A protein in mediating learning and memory impairment under high-altitude hypoxia and suggest the potential of the Nogo-A/NgR1 signaling pathway as a crucial therapeutic target for alleviating learning and memory dysfunction induced by high-altitude exposure. GRAPHICAL ABSTRACT available in www.besjournal.com.
Animals ; Oxidative Stress ; Hippocampus/metabolism* ; Rats ; Nogo Proteins/genetics* ; Male ; Rats, Sprague-Dawley ; Hypoxia/metabolism* ; Altitude ; Synapses ; Humans ; Altitude Sickness/metabolism*

Spinal cord injury is a traumatic disease,commonly seen in falling injuries,traffic accidents,heavy injuries,etc,which could cause motor,sensory and autonomic dysfunction below the level of spinal cord injury.Myelin-associated inhibitors play a role in promoting the collapse of growth cones and inhibiting axonal regeneration in the injured spinal cord microenvironment,which is the main reason for the difficult repair of spinal cord injury.Myelin-associated inhibitors(MAIs),such as neurite outgrowth inhibitor(Nogo),oligodendrocyte-myelin glycoprotein(OMgp)and myelin-associated glycoprotein(MAG),along with their receptor proteins,such as Nogo-A/Nogo-66 receptor 1(NgR1),paired immunoglobulin-like receptor B(PirB),sphingosine-1-phosphate receptor 2(S1PR2),are the important regulatory factors in the spinal cord microenvironment.They can inhibit therepair process of spinal cord injury by affecting the signaling pathway of neuron axon growth.Although the mechanism of spinal cord injury repair is still unclear,the regulation of myelin-related inhibitory factor proteins and downstream signaling pathways remain an important therapeutic approach for spinal cord injury.In this paper,the role of MAI proteins and their receptors in spinal cord injury repair in recent years were reviewed to provide a new target for spinal cord injury repair and provide more ideas for clinical treatment after spinal cord injury.

Objective To establish an acute exposure model of extreme plateau hypobaric hypoxia environment and explore transcriptomic changes related to learning and memory impairment in rats.Methods Healthy male SD rats aged 6-weeks,200-250 g,were selected and divided into control group and plateau group.The control group was treated with normal pressure and oxygen(19 rats),and the plateau group was placed in a hypobaric hypoxia chamber(19 rats)at a simulated altitude of 8000 meters and treated for 72 hours.Behavioral changes were detected with 16 animals from each group using contextual fear conditioning and Morris water maze(8 rats each).Three hippocampal tissues were extracted from each group for transcriptomic sequencing,and the molecular mechanism of learning and memory impairment induced by extreme plateau environment was analyzed by Gene Ontology(GO),Kyoto Encyclopedia of Genes and Genomes(KEGG)and gene set enrichment analysis(GSEA)enrichment.Results The behavioral result showed that compared with the control group,the fear memory and spatial learning memory abilities of rats in plateau group were decreased.GO and KEGG analyses showed that the extreme altitude environment reshaped the hippocampal microenvironment and affected the intercellular signal transmission,while GSEA analysis showed that the extreme altitude environment up-regulated the gene set related to the plasma membrane and extracellular matrix.Conclusion The extreme plateau environment at an altitude of 8000 meters could affect the microenvironment of rat hippocampus,destroy intercellular connections and impair intercellular communication and then induce learning and memory impairment.

Objective To design a novel oxygenator to solve the existing problems of extracorporeal membrane oxygenation(ECMO)machine in high transmembrane pressure difference,low efficiency of blood oxygen exchange and susceptibility to thrombosis.Methods The main body of the oxygenator vascular access flow field was gifted with a flat cylindrical shape.The topology of the vascular access was modeled in three dimensions,and the whole flow field was cut into a blood inlet section,an inlet buffer,a heat exchange zone,a blood oxygen exchange zone,an outlet buffer and a blood outlet section.The oxygenator was compared with Quadrox oxygenator by means of ANSYS FLUENT-based simulation and prototype experiments.Results Simulation calculations showed the oxygenator designed was comparable to the clinically used ones in general,and gained advantages in transmembrane pressure difference,blood oxygen exchange and flow uniformity.Experimental results indicated that the oxygenator behaved better than Quadrox oxygenator in transmembrane pressure difference and blood oxygen exchange.Conclusion The oxygenator has advantages in transmem-brane pressure difference,temperature change,blood oxygen ex-change and low probability of thrombosis.[Chinese Medical Equipment Journal,2024,45(3):23-28]

Aim To explore the protective effect of an-thocyanin B2(PCB2)on hydrogen peroxide(H2O2)induced oxidative damage and apoptosis in human oli-godendrocytes(MO3.13)and the underlying mecha-nism.Methods The optimal concentration of H2O2 and PCB2 for action was screened,and divided into normal group,PCB2 group(100 mg·L-1 PCB2 treat-ment for 24 hours),H2 O2 model group(500 μmol·L-1 H2O2 treatment for 24 hours),and H2O2+PCB2 group(500 μmol·L-1 H2O2 and 100 mg·L-1 PCB2 co-treated for 24 hours).FRAP method was used to detect the antioxidant capacity of PCB2;CCK-8 meth-od was used to detect the survival rate of cells in each group,while LDH method was used to assess cytotoxic-ity.Microenzyme-linked immunosorbent assay and ELISA were used to examine the levels of LDH,NO,H2O2,as well as the activities of CAT and SOD in each group of cells.Immunofluorescence and Western blot were used to detect the protein expression levels of NRF2,xCT,HO-1,ferritin,and GPX4 in each group of cells.FerroOrange fluorescent probe was used to de-tect the intracellular content of ferrous ions(Fe2+).Results H2O2 could induce MO3.13 oxidative dam-age and lead to cell ferroptosis,while PCB2 could alle-viate MO3.13 oxidative damage and ferroptosis.Com-pared with the H2O2 model group,PCB2 intervention could significantly increase LDH content in MO3.13,reduce NO and H2O2 content,and improve SOD and CAT activity,and up-regulate the protein expression levels of NRF2,xCT,HO-1,ferritin,and GPX4.Conclusion PCB2 can enhance cellular antioxidant capacity and alleviate H2O2 induced MO3.13 oxidative damage through the NRF2/HO-1/xCT/GPX4 axis.

Wuzhuyu Decoction, the classical formula recorded in the Treatise on Febrile Diseases(Shang Han Lun), has been included in the Catalogue of Ancient Classic Prescriptions(the First Batch). Consisting of Euodiae Fructus, Ginseng Radix et Rhizoma, Zingiberis Rhizoma Recens, and Jujubae Fructus, it is effective in warming the middle, tonifying deficiency, dispelling cold, and descending adverse Qi, and is widely applied clinically with remarkable efficacies. For a classical formula, the chemical composition is the material basis and an important premise for quantity value transfer. This study aimed to establish a rapid identification method of chemical components in Wuzhuyu Decoction by high-resolution mass spectrometry(HR-MS) and molecular network. AQUITY UPLC BEH C_(18) column(2.1 mm×100 mm, 1.7 μm) was used for sample separation, and acetonitrile-0.1% formic acid in water was used as mobile phases for gradient elution. Q-Exactive Orbitrap MS data were collected in positive and negative ion modes, and GNPS molecular network was plotted according to the similarity of MS/MS fragmentation modes. Cytoscape 3.6.1 was used to screen molecular clusters with similar structures. Finally, the chemical components of Wuzhuyu Decoction were rapidly identified according to the controls, as well as the information of retention time, accurate relative molecular weight of HR-MS, and MS/MS multistage fragments. A total of 105 chemical components were identified in Wuzhuyu Decoction. This study can provide data for the follow-up quality control, standard substance research, and pharmacodynamic material research on Wuzhuyu Decoction, as well as references for the rapid qualitative analysis of the chemical components of Chinese medicine.
Tandem Mass Spectrometry/methods* ; Chromatography, High Pressure Liquid/methods* ; Drugs, Chinese Herbal/chemistry* ; Quality Control

Objective The traditional round incision or cross incision brain harvesting method can not meet the requirements of protecting the donor's remains. In this study, the method of brain removal through a posterior incision on the scalp of both ears was proposed, which effectively protected the donor's remains. Methods Adopting the incision 2. 0 cm above the external occipital protuberance to the most front edge of the auricle to obtain a complete brain. Results The incision did not involve the head and face skin, which was small and conducive to suture repair and reduce exudation. Conclusion The incision effectively protects the donor' s remains, and it will be conducive to the establishment and development of the brain bank.

Aim To explore the protective effect of proanthocyanidin B2 (PC-B2) on oxidative damage of PC 12 cells induced by hydrogen peroxide (H

Objective To investigate the Gram-positive coccus resistance in nationwide's tertiary hospitals and understand the trend of antimicrobial resistance.Methods All the clinical isolates were collected from 19 hospitals and the minimal inhibitory concentrations(MICs)were tested using agar/broth dilution method recommended.Results A total of 1 974 pathogenic Gram-positive coccus from 19 tertiary hospitals in 19 cities nationwide over the period from July 2021 to June 2022 were studied.Based on the MIC results,the prevalence of methicillin resistant Stapylococcus aureus(MRSA)and methicillin resistant Stapylococcus epidermidis(MRSE)were 36.4％and 79.9％respectively.No vancomycin insensitivity Staphylococcus was detected.Staphylococcus aureus were 100％susceptibility to linezolid and teicoplanin.Antibiotic resistance rate of Enterococcus faecalis and Enterococcus faecium to ampicillin were 3.1％and 92.9％.The detectation rate of vancomycin resistant Enterococcus(VRE)was 1.6％.Nonsusceptibility rate of Enterococcus faecalis to linezolid was 32.2％,two consecutive monitoring rises and nonsusceptibility rate of Enterococcus faecium(12.5％)was also significantly increased.The prevalence of penicillin non-susceptible Streptococcus pneumoniae(PNSSP)was 0.8％based on non-meningitis and parenteral administration criterion,decrease of nearly 30 percentage points from the previous surveillance.While for cases of oral penicillin,the rate was 71.8％,showing similar to last time.The results indicated that the number of strains with higher MIC value of penicillin(MIC ≥4 mg·L-1)decreased significantly.There were no significant differences of resistance rates of Stapylococcus aureus,Stapylococcus epidermidis,Enterococcus faecalis,Enterococcus faecium and Streptococcus pneumoniae among various groups such as different department,age,or specimen source.Conclusion VRE detection ratio stablized at a relatively low level.The number of Streptococcus pneumoniae with higher MIC value of penicillin decreased significantly compared with the previous monitoring.The increase of linezolidin-insensitive Enterococcus was noteworthy.

Objective To investigate the Gram-negative bacteria resistance in nationwide's tertiary hospitals and understand the trend of antimicrobial resistance.Method All the clinical isolates were collected from 19 hospitals and the minimal inhibitory concentrations(MICs)were tested using agar/broth dilution method recommended.Results A total of 4 066 pathogenic isolates from 19 tertiary hospitals in 19 cities nationwide over the period from July 2021 to June 2022 were studied.Based on the MIC results,Escherichia coli and Klebsiella pneumoniae showed extended spectrum β-lactamase(ESBLs)phenotype rates of 55.0％and 21.0％,respectively,ESBLs phenotype rate of Klebsiella pneumoniae keep going down.The ratios of carbapenems resistance Klebsiella pneumoniae increased by 5 percentage points compared with the previous monitoring.Carbapenems,moxalactam,sitafloxacin,β-lactam combination agents,fosfomycin trometamol,and amikacin displayed desirable antibacterial activity against Enterbacterales,susceptibal rates were above 75％.In addition,tigacycline,omacycline,colistin and fluoxefin maintained good antibacterial activity against their respective effective bacteria/species,and the bacterial sensitivity rates by more than 80％.Resistance rates of Pseudomonas aeruginosa and Acinetobacter baumannnii to imipenem were 26.3％and 72.1％and multidrug-resistant(MDR)detection rates were 41.1％and 77.3％,extensively drug-resistant(XDR)were 12.0％and 71.8％,respectively.Comparison of drug resistance rates from different wards,ages and specimen sources indicated that the proportion of resistance in Klebsiella pneumoniae and Acinetobacter baumannii isolated from intensive care unit(ICU)were significantly higher than non-ICU.Carbapenem resistance rates of Klebsiella pneumoniae isolated from ICU were more than 35％.Resistance rates of Haemophilus influenzae isolated in children to β-lactam,macrolide,clindamycin and ESBLs detection rate in Klebsiella pneumoniae isolated from children were more than those from adults and the old people,so bacterial resistance in children is an important problem in China.Conclusion ESBLs detection rate of Escherichia coli increased slightly after years of continuous decline.The proportion of carbapenem resistant Pseudomonas aeruginosa was stable,but the resistance rate of Klebsiella pneumoniae and Acinetobacter baumannii to carbapenems was still increased,which should be paid more attention.