ObjectiveTo explore the role and potential mechanism of circulating glutamate in enhancing insulin sensitivity by aerobic exercise. This research may provide a novel strategy for preventing metabolic diseases through precise exercise interventions. MethodsTo investigate the effects of elevated circulating glutamate on insulin sensitivity and its potential mechanisms, 18 male C57BL/6 mice aged 6 to 8 weeks were randomly divided into 3 groups: a control group (C), a group receiving 500 mg/kg glutamate supplementation (M), and a group receiving 1 000 mg/kg glutamate supplementation (H). The intervention lasted for 12 weeks, with treatments administered 6 d per week. Following the intervention, an insulin tolerance test (ITT) and a glucose tolerance test (GTT) were conducted. Circulating glutamate levels were measured using a commercial kit, and the activity of the skeletal muscle InsR/IRS1/PI3K/AKT signaling pathway was analyzed via Western blot. To further investigate the role of circulating glutamate in enhancing insulin sensitivity through aerobic exercise, 30 male C57BL/6 mice were randomly assigned to 3 groups: a control group (CS), an exercise intervention group (ES), and an exercise combined with glutamate supplementation group (EG). The ES group underwent treadmill-based aerobic exercise, while the EG group received glutamate supplementation at a dosage of 1 000 mg/kg in addition to aerobic exercise. The intervention lasted for 10 weeks, with sessions occurring 6 d per week, and the same procedures were followed afterward. To further elucidate the mechanism by which glutamate modulates the InsR/IRS1/PI3K/AKT signaling pathway, C2C12 myotubes were initially subjected to graded glutamate treatment (0, 0.5, 1, 3, 5, 10 mmol/L) to determine the optimal concentration for cellular intervention. Subsequently, the cells were divided into 3 groups: a control group (C), a glutamate intervention group (G), and a glutamate combined with MK801 (an NMDA receptor antagonist) intervention group (GK). The G group was treated with 5 mmol/L glutamate, while the GK group received 50 μmol/L MK801 in addition to 5 mmol/L glutamate. After 24 h of intervention, the activity of the InsR/IRS1/PI3K/AKT signaling pathway was analyzed using Western blot. ResultsCompared to the mice in group C, the circulating glutamate levels, the area under curve (AUC) of ITT, and the AUC of GTT in the mice of group H were significantly increased. Additionally, the expression levels of p-InsRβ, IRS1, p-AKT, and p-mTOR proteins in skeletal muscle were significantly downregulated. Compared to the mice in group CS, the circulating glutamate levels, the AUC of ITT, and the AUC of GTT in the mice of group ES were significantly reduced. Additionally, the expression levels of p-InsRβ, IRS1, p-AKT, and p-mTOR proteins in skeletal muscle of group ES mice were significantly upregulated. There were no significant changes observed in the mice of group EG. Compared to the cells in group 0 mmol/L, the expression levels of p-InsRβ, p-IRS1, p-PI3K, and p-AKT proteins in cells of group 5 mmol/L were significantly downregulated. Compared to the cells in group C, the expression levels of p-InsRβ, p-IRS1, p-PI3K, and p-AKT proteins in the cells of group G were significantly downregulated. No significant changes were observed in the cells of group GK. ConclusionLong-term aerobic exercise can improve insulin sensitivity by lowering circulating levels of glutamate. This effect may be associated with the upregulation of the InsR/IRS1/AKT signaling pathway activity in skeletal muscle. Furthermore, glutamate can weaken the activity of the InsR/IRS1/PI3K/AKT signaling pathway in skeletal muscle, potentially by binding to NMDAR expressed in skeletal muscle.

Objective To explore the protective mechanism of icariin on neuronal oxidative damage,providing a basic pharmacological basis for the treatment of cognitive impairment.Methods Glutamate was used to induce oxidative stress injury in HT22 cells.HT22 cells were divided into control group(normal cultured cells),model group(glutamate injury model)and experimental-L,-M,-H groups(5,10 and 20 μmol·L-1 icariin pretreatment for modeling,respectively).Cell proliferation was detected by cell counting kit-8(CCK-8)method;cytotoxicity was detected by lactate dehydrogenase(LDH)method;reactive oxygen species(ROS)levels were detected by flow cytometry;superoxide dismutase(SOD)levels were detected by biochemical kits;the expression levels of Kelch-like epichlorohydrin-related protein-1(Keap1),nuclear factor E2-related factor 2(Nrf2)were detected by Western blotting;the corresponding mRNA expression was detected by real-time fluorescence quantification polymerose chain reaction.Results The cell viability of control group,model group and experimental-L,-M,-H groups were(100.00±1.31)％,(66.38±2.44)％,(72.07±4.95)％,(82.41±3.57)％and(87.97±4.98)％;LDH release were(0.48±0.52)％,(18.82±2.09)％,(15.32±1.17)％,(10.37±1.39)％and(6.51±0.87)％;ROS level were(14.23±1.13)％,(41.74±1.60)％,(35.69±1.08)％,(33.28±1.69)％and(30.32±2.03)％;SOD levels were(54.84±1.17),(37.95±1.13),(48.02±1.28),(50.56±1.34)and(52.55±1.04)U·mg-1;Keap1 protein levels were 0.36±0.01,0.52±0.03,0.46±0.04,0.39±0.09 and 0.35±0.12;Nrf2 protein levels were 0.29±0.02,0.13±0.08,0.18±0.03,0.21±0.11 and 0.26±0.04;catalase(CAT)mRNA levels were 1.01±0.08,0.81±0.06,0.90±0.04,1.05±0.15 and 1.33±0.26;SOD mRNA levels were 1.09±0.12,0.83±0.03,0.86±0.08,0.94±0.08 and 1.09±0.16.Among the above indicators,the differences between the model group and the control group were statistically significant(all P＜0.01);the differences between the experimental-M,-H groups and the model group were statistically significant(P＜0.01,P＜0.05).Conclusion Icariin may activate the Keap1/Nrf2/antioxidant response element(ARE)signaling pathway,regulate the expression of related proteins,and reduce the level of ROS to effectively alleviate oxidative stress injury in neuronal cells.

AIM: To observe the changes of corneal densitometry(CD)in patients with keratoconus after corneal cross-linking(CXL).METHODS: Retrospective study. A total of 32 patients(43 eyes)with keratoconus in Ningxia Eye Hospital from April 2020 to April 2022 were selected. Pentacam analysis system divided the cornea into three layers: anterior 120 μm, middle layer and posterior 60 μm, and divides it into five regions with diameters of 0-2, 2-6, 6-10, 10-12 mm and full diameter according to the diameter, and measures the CD in different ranges. The changes of CD were compared before operation and at 1, 3 and 6 mo after operation.RESULTS: There were differences in uncorrected visual acuity, best corrected visual acuity and intraocular pressure before and 6 mo after operation(all P<0.05), and there was no difference in corneal endothelial cells(P=0.477). CD reached its peak at 1 mo after operation, and decreased at 3 mo and 6 mo after operation, but it was still higher than that before operation. There is a significant positive correlation between CD and Kmax in the anterior layer and the whole layer(r=0.164, P=0.016; r=0.152, P=0.023).CONCLUSION: The values of CD peaked at 1 mo after CXL, then it gradually decreased, tending to become stable at 6 mo postoperatively.

As the predominant toxic constituent within the Aconitum genus, Aconitum alkaloids (ATs) exhibit both significant pharmaceutical value and substantial toxicity, have been widely used in traditional Chinese medicine and the realm of contemporary clinical medicine. However, owing to their high toxicity, inappropriate employment of ATs in pharmaceuticals, edibles, and the environment will pose serious threats to human health, inciting a series of toxic incidents. Consequently, it is very important to develop effective analytical methods. This paper presents a comprehensive review of the advancements in research pertaining to the pretreatment and detection methods in common substrates, including high performance liquid chromatography, liquid chromatography-mass spectrometry and rapid detection methods. To explore the specific sources of ATs in actual poisoning cases, the comprehensive traceability strategy based on plant morphology, chemical fingerprint analysis and DNA barcoding technology was discussed, proposing a comprehensive prospect for the development of ATs analysis and traceability, in order to provide guidance for related research within the forensic science domain.

Objective To investigate the imaging features of intestinal schwannoma(IS)in order to improve the diagnostic ability of the disease.Methods The clinical and imaging data of 14 patients with surgically and pathologically confirmed IS were retrospectively analyzed,including the location,size,morphology,nature,growth pattern,CT density,MRI signal,PET/CT metabolism and other characteristics of the tumors.Results Of the 14 IS cases,the lesions of 3 cases were located in the duodenum,2 cases in the cecum,8 cases in the colon and 1 case in the rectum.The lesions were all round or oval,with an average maximum diameter of(2.4±1.1)cm.The lesions were solid in 13 cases,extraluminal growth in 10 cases,cystic degeneration in 1 case and myxoid degeneration in 1 case.Chronic inflammatory lymph nodes were seen around the diseased intestines in 9 cases,and the short diameter of lymph nodes was greater than 5 mm in 6 cases.All 14 cases of IS showed low attenuation on plain CT scan,and progressive enhancement after contrast injection,including 1 case of mild enhancement,2 cases of moderate enhancement,and 11 cases of obvious enhancement.Two cases of IS showed low signal intensity on T1WI,slightly high signal intensity on T2WI,significantly high signal intensity on DWI,and obvious progressive enhancement after contrast injection on MRI.Two cases of IS showed high metabolism on 18F-FDG-PET/CT,and the SUVmax was 9.4 and 8.8,respectively.Conclusion The imaging findings of IS were characteristic to a certain extent.They mainly manifested as solid nodules or masses derived from the intestinal submucosa,with uniform attenuation or signal intensity,obvious progressive enhancement after contrast injection,obvious hypermetabolism on 18F-FDG-PET/CT,and slightly larger homogeneous lymph nodes were common around the lesions.

Endo-beta-N-acetylglucosaminidase (ENGase) is widely distributed in various organisms. The first reported ENGase activity was detected in Diplococcus pneumoniae in 1971. The protein (Endo D) was purified and its peptide sequence was determined in 1974. Three ENGases (Endo F1-F3) were discovered in Flavobacterium meningosepticum from 1982 to 1993. After that, the activity was detected from different species of bacteria, yeast, fungal, plant, mice, human, etc. Multiple ENGases were detected in some species, such as Arabidopsis thaliana and Trichoderma atroviride. The first preliminary crystallographic analysis of ENGase was conducted in 1994. But to date, only a few ENGases structures have been obtained, and the structure of human ENGase is still missing. The currently identified ENGases were distributed in the GH18 or GH85 families in Carbohydrate-Active enZyme (CAZy) database. GH18 ENGase only has hydrolytic activity, but GH85 ENGase has both hydrolytic and transglycosylation activity. Although ENGases of the two families have similar (β/α)8-TIM barrel structures, the active sites are slightly different. ENGase is an effective tool for glycan detection andglycan editing. Biochemically, ENGase can specifically hydrolyze β‑1,4 glycosidic bond between the twoN-acetylglucosamines (GlcNAc) on core pentasaccharide presented on glycopeptides and/or glycoproteins. Different ENGases may have different substrate specificity. The hydrolysis products are oligosaccharide chains and a GlcNAc or glycopeptides or glycoproteins with a GlcNAc. Conditionally, it can use the two products to produce a new glycopeptides or glycoprotein. Although ENGase is a common presentation in cell, its biological function remains unclear. Accumulated evidences demonstrated that ENGase is a none essential gene for living and a key regulator for differentiation. No ENGase gene was detected in the genomes of Saccharomyces cerevisiae and three other yeast species. Its expression was extremely low in lung. As glycoproteins are not produced by prokaryotic cells, a role for nutrition and/or microbial-host interaction was predicted for bacterium produced enzymes. In the embryonic lethality phenotype of the Ngly1-deficient mice can be partially rescued by Engase knockout, suggesting down regulation of Engase might be a solution for stress induced adaptation. Potential impacts of ENGase regulation on health and disease were presented. Rabeprazole, a drug used for stomach pain as a proton inhibitor, was identified as an inhibitor for ENGase. ENGases have been applied in vitro to produce antibodies with a designated glycan. The two step reactions were achieved by a pair of ENGase dominated for hydrolysis of substrate glycoprotein and synthesis of new glycoprotein with a free glycan of designed structure, respectively. In addition, ENGase was also been used in cell surface glycan editing. New application scenarios and new detection methods for glycobiological engineering are quickly opened up by the two functions of ENGase, especially in antibody remodeling and antibody drug conjugates. The discovery, distribution, structure property, enzymatic characteristics and recent researches in topical model organisms of ENGase were reviewed in this paper. Possible biological functions and mechanisms of ENGase, including differentiation, digestion of glycoproteins for nutrition and stress responding were hypothesised. In addition, the role of ENGase in glycan editing and synthetic biology was discussed. We hope this paper may provide insights for ENGase research and lay a solid foundation for applied and translational glycomics.

Protein as the allergens could lead to allergy. In addition, a widespread class of allergens were known as glycans of N-glycoprotein. N-glycoprotein contained oligosaccharide linked by covalent bonds with protein. Recently,studies implicated that allergy was associated with glycans of heterologous N-glycoprotein found in food, inhalants, insect toxins, etc. The N-glycan structure of N-glycoprotein allergen has exerted an influence on the binding between allergens and IgE, while the recognition and presentation of allergens by antigen-presenting cells (APCs) were also affected. Some researches showed thatN-glycan structure of allergen was remodeled by N-glycosidase, such as cFase I, gpcXylase, as binding of allergen and IgE partly decreased. Thus, allergic problems caused by N-glycoproteins could potentially be solved by modifying or altering the structure ofN-glycoprotein allergens, addressing the root of the issue. Mechanism of N-glycans associated allergy could also be elaborated through glycosylation enzymes, alterations of host glycosylation. This article hopes to provide a separate insight for glycoimmunology perspective, and an alternative strategy for clinical prevention or therapy of allergic diseases.

The World Health Organization (WHO) released the “Global report on hypertension” on September 19, 2023. This report systematically summarizes the prevalence, mortality, diagnosis and treatment of hypertension in various countries, and elucidates the current situation of hypertension management, and gives a series of suggestions on how to manage hypertension, providing new thinking and inspiration for countries to optimize hypertension management. Through the summary of relevant studies and reports, this paper further reviews the present situation, early identification and management of hypertension.

AIM:To investigate whether the expression of perilipin 2(PLIN2)in renal tubular cells could predict a decline in renal function in diabetic kidney disease(DKD)patients,and to explore the potential mechanisms in-volved in renal tubular cell injury induced by PLIN2 during the progression of DKD.METHODS:Control individuals(n=12)and DKD patients(n=51)were enrolled in this retrospective cohort study.Demographic and laboratory data were col-lected.A simplified linear mixed-effects model was applied to assess the estimated glomerular filtration rate(eGFR)slope.The relationship between PLIN2 and renal function decline in DKD patients was predicted by Spearman correlation analysis and a generalized linear model.BKS-db/db diabetic mice and streptozotocin-induced diabetic mice were used.Primary renal tubular cells were treated with glucose and transfected with small interfering RNA or plasmid.Western blot-ting and immunofluorescence staining were used to detect PLIN2 expression.Lipid droplets were stained with oil red O.The oxygen consumption rate(OCR)of mitochondria was measured using an extracellular flux analyser.RESULTS:The expression of PLIN2 was markedly higher in the tubules of DKD patients than in those of control subjects.After 24(12,39)months of follow-up,the eGFR slope of DKD patients was-7.42(-19.77,-2.09)mL/(min·1.73 m2·year).An in-crease in the baseline percentage of PLIN2-positive tubules was significantly associated with the eGFR slope during the fol-low-up period[hazard ratio(HR)=1.90,95%confidence interval(CI):1.00～3.58],indicating that tubular PLIN2 could predict a decrease in renal function in DKD patients.Both the accumulation of lipid droplets and the expression of PLIN2 were markedly greater in the tubules of diabetic mice than in those of control mice.Glucose treatment induced lipid droplet accumulation and PLIN2 expression in renal tubular cells.Knockdown of PLIN2 significantly alleviated glucose-in-duced lipid droplet accumulation,whereas PLIN2 overexpression aggravated glucose-induced lipid droplet accumulation.The decrease in mitochondrial OCR in renal tubular cells induced by glucose treatment was alleviated after PLIN2 knock-down.However,overexpression of PLIN2 directly decreased the mitochondrial OCR.CONCLUSION:The PLIN2 ex-pression in tubules predicts a decline in renal function in patients with DKD.The PLIN2 suppresses mitochondrial aerobic respiration and contributes to the accumulation of lipid droplets in renal tubular cells to promote the progression of DKD.

Objective To explore the changes in gut microbiota and levels of short-chain fatty acids(SCFA)in infants with cow's milk protein allergy(CMPA),and to clarify their role in CMPA.Methods A total of 25 infants diagnosed with CMPA at Children's Hospital Affiliated to Zhengzhou University from August 2019 to August 2020 were enrolled as the CMPA group,and 25 healthy infants were selected as the control group.Fecal samples(200 mg)were collected from both groups and subjected to 16S rDNA high-throughput sequencing technology and liquid chromatography-mass spectrometry to analyze the changes in gut microbial composition and metabolites.Microbial diversity was analyzed in conjunction with metabolites.Results Compared to the control group,the CMPA group showed altered gut microbial structure and significantly increased α-diversity(P＜0.001).The abundance of Firmicutes,Clostridiales and Bacteroidetes was significantly decreased,while the abundance of Sphingomonadaceae,Clostridiaceae_l and Mycoplasmataceae was significantly increased in the CMPA group compared to the control group(P＜0.001).Metabolomic analysis revealed reduced levels of acetic acid,butyric acid,and isovaleric acid in the CMPA group compared to the control group,and the levels of the metabolites were positively correlated with the abundance of SCFA-producing bacteria such as Faecalibacterium and Roseburia(P＜0.05).Conclusions CMPA infants have alterations in gut microbial structure,increased microbial diversity,and decreased levels of SCFA,which may contribute to increased intestinal inflammation.[Chinese Journal of Contemporary Pediatrics,2024,26(3):236-243]