This study was aimed at identifying the pathogenic bacteria responsible for the death of a young tiger at the Fujian Meihua Mountain South China Tiger Breeding Research Institute.Tissue samples from the lungs,liver,and intestines of the deceased tiger were collected,and the bacteria were cultured inasterile environment.The bacterial strains were characterized according to their morphological and molecular biological properties,including assessment of virulence genes and antibiotic resistance genes,mouse lethality tests,and antibiotic susceptibility evaluations.A predominant bacterial strain isolated from the liver of the deceased tiger was identified as enterotoxigenic Escherichia coli(ETEC)strain Tiger22513F.Phylogenetic analysis of the 16S rRNA gene revealed that the Tiger22513F strain exhibited close genetic similarity to the reference strain ETEC(MF919609.1),with 99.9%nucleotide similarity,and resided on the same evolutionary branch.The Tiger22513F strain contained 11 antibiotic resistance genes(tetA,sul1,sul3,cmlA,floR,blaTEM,blaSHV,blaCMY-2,qnrA,qnrS,and qnrD)along with five virulence genes(VT1,fyuA,tsh,iucD,and ST).Mouse lethality tests indicated significant pathogenicity toward mice,affecting primarily the lungs,liver,and intestines.Antibiotic susceptibility testing demonstrated that this strain exhibited resistance to various classes of beta-lactam antibiotics,as well as quinolones and aminoglycosides.This investigation successfully isolated a multi-drug resistant enterotoxigenic Escherichia coli strain with pronounced pathogenicity from the liver of a deceased tiger;thus providing valuable scientific insights for clinical diagnosis,as well as prevention and control measures,against ETEC infections in South China tigers.

Objective:To investigate the effects of TP53 genetic status(wild-type/mutated/null)on the drug resistance of decitabine(DAC)in myelodysplastic syndromes(MDS)and identify key resistance-associated genes.Methods:Two myeloid cell lines with distinct TP53 status(M-07e:wild-type;SKM-1:mutated;)were treated with gradient DAC concentrations(0-10 μmol/L)for 0-72 h.Cell viability was detected by CCK-8 assay.RNA-Seq transcriptomics,and methylation profiling were integrated to analyze differentially expressed genes.Results:Decitabine(DAC)treatment induced time-and dose-dependent inhibition of cell viability in CCK-8 assays,with SKM-1 cells exhibiting the highest resistance(IC50=5 μmol/L vs M-07e=0.5 μmol/L,P＜0.01).Transcriptomic analysis revealed 662 upregulated and 452 downregulated genes in DAC-treated M-07e cells,while SKM-1 cells showed 515 upregulated and 73 downregulated genes.By proteomic profiling,117 upregulated and 136 downregulated proteins were identified in M-07e cells,while 91 upregulated and 46 downregulated proteins were identified in SKM-1 cells following DAC exposure.Through integrated analysis of upregulated genes and proteins expression profiles,181 candidate genes were screened out,while methylation studies identified 884 hypomethylated genes with high-sensitivity loci and CpG density.Notably,31 genes overlapped between these datasets,and functional annotation indicated these drug-resistance-associated genes are primarily involved in positive regulation of cell differentiation,negative regulation of binding processes,and negative regulation of cellular component organization.Conclusion:TP53 mutations drive DAC resistance via epigenetic reprogramming.Targeting these genes may improve outcomes in TP53-mutated MDS.

Objective:To investigate the incidence,clinical characteristics,and complications of Torque teno virus(TTV)in children after hematopoietic stem cell transplantation(HSCT).Methods:A total of 40 children with hematological diseases who underwent HSCT were selected,and metagenomic next-generation sequencing(mNGS)technology was used to detect the gene sequences of pathogenic microorganisms in the blood.Combined with clinical data,the characteristics of TTV infection were analyzed.Results:Among the 40 pediatric patients post-HSCT,the TTV positive rate was 42.5％(17/40).There were no statistically significant differences between the TTV-positive group and the TTV-negative group in sex,age,white blood cell count(WBC),red blood cell count(RBC),hemoglobin,platelet count,neutrophil count,lymphocyte count,and high-sensitivity C-reactive protein(all P＞0.05).The incidence of TTV infection was significantly higher in children who underwent haploidentical HSCT and in those with bone marrow stem cells(BMSC)as the transplant source(P＜0.05).However,there were no significant differences in the TTV infection rate among patients with different disease types,different HLA matching statuses,or different engraftment times of neutrophils and platelets(all P＞0.05).Among 17 children infected with TTV,13(76.5％)had co-infections with other viruses,mainly including cytomegalovirus(58.8％,10/17),human polyomavirus(41.2％,7/17),and Epstein-Barr virus(17.6％,3/17).In children with TTV infection,the most common complications were sepsis(82.4％),graft-versus-host disease(GVHD)(70.6％),pulmonary infection(41.2％),and hemorrhagic cystitis(17.6％).The incidence of GVHD in the TTV-positive group was significantly higher than that in the TTV-negative group(P＜0.05).Conclusion:TTV infection is common in children undergoing HSCT,and it is prone to be complicated with cytomegalovirus infection and GVHD,which has an important influence on the clinical outcomes.

Objective:To establish a TaqMan-MGB probe-based method for detecting the polymorphic loci C677T and A1298C of the MTHFR gene.Methods:Specific primers and TaqMan-MGB probes targeting the C677T and A1298C polymorphic loci of the MTHFR gene were designed and optimized based on the gene sequence information.A real-time quantitative PCR detection system was established.Gradient dilution experiments were conducted to determine the limit of detection,and reproducibility experiments were performed to evaluate detection consistency.Specificity was validated using wild-type and mutant plasmid templates.The method was applied to detect 56 clinical samples,and its accuracy and practicality were assessed through comparison with traditional Sanger sequencing.Results:The TaqMan-MGB probe method demonstrated high specificity for detecting the C677T and A1298C loci,with no cross-reactivity between wild-type and mutant probes,enabling accurate genotype differentiation.Sensitivity experiments revealed detection limits of 1.13 × 103 copies/μL for C677T and 8.39 × 101 copies/μL for A1298C.Reproducibility experiments showed coefficients of variation below 1％,indicating stable and reliable results.Among the 56 clinical samples,the overall detection rate for the C677T locus was 86.99％,and for the A1298C locus,it was 97.92％.The TaqMan-MGB method exhibited good concordance with Sanger sequencing results.Conclusion:The TaqMan-MGB method exhibits high specificity,sensitivity,and excellent reproducibility in detecting the polymorphic loci C677T and A1298C of the MTHFR gene,making it suitable for rapid detection in large-scale clinical samples.This method provides an effective molecular diagnostic tool for the early diagnosis and prevention of folate-related diseases.

This study was aimed at identifying the pathogenic bacteria responsible for the death of a young tiger at the Fujian Meihua Mountain South China Tiger Breeding Research Institute.Tissue samples from the lungs,liver,and intestines of the deceased tiger were collected,and the bacteria were cultured inasterile environment.The bacterial strains were characterized according to their morphological and molecular biological properties,including assessment of virulence genes and antibiotic resistance genes,mouse lethality tests,and antibiotic susceptibility evaluations.A predominant bacterial strain isolated from the liver of the deceased tiger was identified as enterotoxigenic Escherichia coli(ETEC)strain Tiger22513F.Phylogenetic analysis of the 16S rRNA gene revealed that the Tiger22513F strain exhibited close genetic similarity to the reference strain ETEC(MF919609.1),with 99.9%nucleotide similarity,and resided on the same evolutionary branch.The Tiger22513F strain contained 11 antibiotic resistance genes(tetA,sul1,sul3,cmlA,floR,blaTEM,blaSHV,blaCMY-2,qnrA,qnrS,and qnrD)along with five virulence genes(VT1,fyuA,tsh,iucD,and ST).Mouse lethality tests indicated significant pathogenicity toward mice,affecting primarily the lungs,liver,and intestines.Antibiotic susceptibility testing demonstrated that this strain exhibited resistance to various classes of beta-lactam antibiotics,as well as quinolones and aminoglycosides.This investigation successfully isolated a multi-drug resistant enterotoxigenic Escherichia coli strain with pronounced pathogenicity from the liver of a deceased tiger;thus providing valuable scientific insights for clinical diagnosis,as well as prevention and control measures,against ETEC infections in South China tigers.

Objective:To investigate the effects of TP53 genetic status(wild-type/mutated/null)on the drug resistance of decitabine(DAC)in myelodysplastic syndromes(MDS)and identify key resistance-associated genes.Methods:Two myeloid cell lines with distinct TP53 status(M-07e:wild-type;SKM-1:mutated;)were treated with gradient DAC concentrations(0-10 μmol/L)for 0-72 h.Cell viability was detected by CCK-8 assay.RNA-Seq transcriptomics,and methylation profiling were integrated to analyze differentially expressed genes.Results:Decitabine(DAC)treatment induced time-and dose-dependent inhibition of cell viability in CCK-8 assays,with SKM-1 cells exhibiting the highest resistance(IC50=5 μmol/L vs M-07e=0.5 μmol/L,P＜0.01).Transcriptomic analysis revealed 662 upregulated and 452 downregulated genes in DAC-treated M-07e cells,while SKM-1 cells showed 515 upregulated and 73 downregulated genes.By proteomic profiling,117 upregulated and 136 downregulated proteins were identified in M-07e cells,while 91 upregulated and 46 downregulated proteins were identified in SKM-1 cells following DAC exposure.Through integrated analysis of upregulated genes and proteins expression profiles,181 candidate genes were screened out,while methylation studies identified 884 hypomethylated genes with high-sensitivity loci and CpG density.Notably,31 genes overlapped between these datasets,and functional annotation indicated these drug-resistance-associated genes are primarily involved in positive regulation of cell differentiation,negative regulation of binding processes,and negative regulation of cellular component organization.Conclusion:TP53 mutations drive DAC resistance via epigenetic reprogramming.Targeting these genes may improve outcomes in TP53-mutated MDS.

Objective:To investigate the incidence,clinical characteristics,and complications of Torque teno virus(TTV)in children after hematopoietic stem cell transplantation(HSCT).Methods:A total of 40 children with hematological diseases who underwent HSCT were selected,and metagenomic next-generation sequencing(mNGS)technology was used to detect the gene sequences of pathogenic microorganisms in the blood.Combined with clinical data,the characteristics of TTV infection were analyzed.Results:Among the 40 pediatric patients post-HSCT,the TTV positive rate was 42.5％(17/40).There were no statistically significant differences between the TTV-positive group and the TTV-negative group in sex,age,white blood cell count(WBC),red blood cell count(RBC),hemoglobin,platelet count,neutrophil count,lymphocyte count,and high-sensitivity C-reactive protein(all P＞0.05).The incidence of TTV infection was significantly higher in children who underwent haploidentical HSCT and in those with bone marrow stem cells(BMSC)as the transplant source(P＜0.05).However,there were no significant differences in the TTV infection rate among patients with different disease types,different HLA matching statuses,or different engraftment times of neutrophils and platelets(all P＞0.05).Among 17 children infected with TTV,13(76.5％)had co-infections with other viruses,mainly including cytomegalovirus(58.8％,10/17),human polyomavirus(41.2％,7/17),and Epstein-Barr virus(17.6％,3/17).In children with TTV infection,the most common complications were sepsis(82.4％),graft-versus-host disease(GVHD)(70.6％),pulmonary infection(41.2％),and hemorrhagic cystitis(17.6％).The incidence of GVHD in the TTV-positive group was significantly higher than that in the TTV-negative group(P＜0.05).Conclusion:TTV infection is common in children undergoing HSCT,and it is prone to be complicated with cytomegalovirus infection and GVHD,which has an important influence on the clinical outcomes.

Objective:To establish a TaqMan-MGB probe-based method for detecting the polymorphic loci C677T and A1298C of the MTHFR gene.Methods:Specific primers and TaqMan-MGB probes targeting the C677T and A1298C polymorphic loci of the MTHFR gene were designed and optimized based on the gene sequence information.A real-time quantitative PCR detection system was established.Gradient dilution experiments were conducted to determine the limit of detection,and reproducibility experiments were performed to evaluate detection consistency.Specificity was validated using wild-type and mutant plasmid templates.The method was applied to detect 56 clinical samples,and its accuracy and practicality were assessed through comparison with traditional Sanger sequencing.Results:The TaqMan-MGB probe method demonstrated high specificity for detecting the C677T and A1298C loci,with no cross-reactivity between wild-type and mutant probes,enabling accurate genotype differentiation.Sensitivity experiments revealed detection limits of 1.13 × 103 copies/μL for C677T and 8.39 × 101 copies/μL for A1298C.Reproducibility experiments showed coefficients of variation below 1％,indicating stable and reliable results.Among the 56 clinical samples,the overall detection rate for the C677T locus was 86.99％,and for the A1298C locus,it was 97.92％.The TaqMan-MGB method exhibited good concordance with Sanger sequencing results.Conclusion:The TaqMan-MGB method exhibits high specificity,sensitivity,and excellent reproducibility in detecting the polymorphic loci C677T and A1298C of the MTHFR gene,making it suitable for rapid detection in large-scale clinical samples.This method provides an effective molecular diagnostic tool for the early diagnosis and prevention of folate-related diseases.

A liquid chromatography-tandem mass spectrometry method was established and validated for determining the concentrations of costunolide(CO), piperine(PI), agarotetrol(AG), glycyrrhizic acid(GL), vanillic acid(VA), and glycyrrhetinic acid(GA) in rat plasma. This method was then applied to the toxicokinetic study of these six compounds in rats with chronic cerebral ischemia(CCI) following multiple oral doses of Zhachong Shisanwei Pills. Finally, the effects of continuous multiple-dose administration of Zhachong Shisanwei Pills on the liver of CCI rats were investigated. The results showed that after oral administration of different doses of Zhachong Shisanwei Pills, the in vivo exposure of AG, VA, and GA was relatively high, with AUC_(0-∞) values ranging from 604.0-2 494.2, 1 305.4-4 634.5, and 2 177.5-4 045.7 h·ng·mL~(-1), respectively, while the exposure of CO, PI, and GL was relatively low, with AUC_(0-∞) values ranging from 37.8-238.2, 2.4-17.0, and 146.9-408.5 h·ng·mL~(-1), respectively. The C_(max) and AUC_(0-∞) of the six compounds were positively correlated with the administered dose. The T_(max) of PI and AG ranged from 0.3 to 2.0 h, their T_(1/2) ranged from 0.8 to 2.9 h, and their mean residence time(MRT) ranged from 1.0 to 3.7 h. The T_(max) of GL and VA was shorter(0.4-1.9 h), while their T_(1/2)(2.6-5.9 h) and MRT(2.5-8.5 h) were longer. Both CO and GA exhibited a bimodal phenomenon, with T_(max) ranging from 1.6 to 6.6 h, T_(1/2) ranging from 2.8 to 7.7 h, and MRT ranging from 4.1 to 12.9 h. Liver histopathology after 28 days of continuous multiple-dose administration of Zhachong Shisanwei Pills showed that the liver tissue remained normal at a low dose(crude drug 0.8 g·kg~(-1), approximately 5 times the clinical equivalent dose). However, as the dose increased(crude drug 1.1-3.0 g·kg~(-1), 6.9-18.8 times the clinical equivalent dose), varying degrees of liver damage were observed. Blood biochemical tests revealed no significant changes in the serum levels of alanine aminotransferase(ALT), aspartate aminotransferase(AST), alkaline phosphatase(ALP), and total bile acid(TBA) in CCI rats from administration groups 1 to 3(crude drug 0.8, 1.1, 1.5 g·kg~(-1)). However, ALT, AST, ALP, and TBA levels in groups 4 and 5(crude drug 2.1, 3.0 g·kg~(-1)) showed significant increases. This study preliminarily elucidated the toxicokinetic characteristics of the six compounds in Zhachong Shisanwei Pills and their effects on liver tissue in CCI rats, providing data as a reference for clinical use.
Animals ; Tandem Mass Spectrometry/methods* ; Rats ; Drugs, Chinese Herbal/toxicity* ; Male ; Rats, Sprague-Dawley ; Brain Ischemia/blood* ; Chromatography, Liquid/methods* ; Polyunsaturated Alkamides/blood* ; Piperidines/toxicity* ; Benzodioxoles/toxicity* ; Alkaloids/blood* ; Liquid Chromatography-Mass Spectrometry

This experiment aims to study the taste-masking effects of different kinds of corrigent used individually and in combination on ibuprofen oral solution, in order to optimize the taste-masking formulation. Firstly, a wide range of corrigent and the mass fractions were extensively screened using electronic tongue technology. Subsequently, a combination of sensory evaluation, analytic hierarchy process (AHP)-fuzzy mathematics evaluation, and Box-Behnken experimental design were employed to comprehensively assess the taste-masking effects of different combinations of corrigent on ibuprofen oral solution, optimize the taste-masking formulation, and validate the results. The study received ethical approval from the Review Committee of the Beijing University of Chinese Medicine (ethical code: 2024BZYLL0102). The results showed that corrigent fractions and types were screened separately through single-factor experiments. Subsequently, a Box-Behnken response surface design combined with AHP and fuzzy mathematics evaluation was used to fit a functional model: Z = 688.310 11 - 3 023.722 22X₁ - 11.477 00X₂ + 62.721 67X₃ + 14.600 00X₁X₂ - 179.666 67X₁X₃ - 3.152 00X₂X₃ + 4 031.111 11X₁² + 0.525 28X₂² + 9.772 00X₃². This model is stable and reliable, determining the optimal taste-masking formulation to be 3.9 g·L^-1 of stevioside, 100 g L^-1 of xylitol, and 30 g L^-1 of methyl-β-cyclodextrin. The comprehensive score of the verification test is 88.14, with a relative RSD of 0.39%, indicating the feasibility of this model. This study achieved the improvement of the taste of ibuprofen oral solution through a combination of objective and subjective methods. Three types of corrigent were identified for enhancing drug taste, leading to the selection of the optimal taste-masking formulation for ibuprofen oral solution. This significantly enhanced the taste of the original formulation, improved patient compliance, and offered a new approach to mitigating the undesirable taste of formulations.