Objective To isolate pathogenic bacteria from the skin of a nude mouse exhibiting squamous skin scurfs, and perform bacterial identification, traceability analysis, and pathogenicity studies to provide a new approach for the diagnosis of pathogens in nude mice with squamous skin scurfs. MethodsSkin swab samples were collected from a nude mouse exhibiting squamous skin scurfs for nucleic acid testing, bacterial isolation and culture, biochemical identification, 16S rDNA gene amplification and sequencing, and whole genome sequencing to construct a phylogenetic tree. Fifteen BALB/c nude mice were randomized into a saline-treated control group, a high-concentration group treated with 1.8×10⁸ CFU/mL of the isolated bacterial suspension, and a low-concentration group treated with 1.8×10⁷ CFU/mL of the isolated bacterial suspension. Pathogenicity was assessed by animal infection experiments and observation of histopathological changes in skin tissue using HE staining. Results The nucleic acid test for Corynebacterium bovis was negative, excluding infection by this organism. The pathogen isolated on mannitol salt agar and blood agar, combined with Gram staining, suggested a Gram-positive Staphylococcus species. The isolated strain was identified by 16S rDNA sequencing and a fully automated microbial identification system as Staphylococcus xylosus. Phylogenetic tree analysis based on whole genome sequencing showed that the strain was most closely related to an isolate from leafy vegetables in South Korea (GenBank GCA_00207825.1). In the high-concentration group, squamous skin scurfs appeared on the head, neck, and back of nude mice on the 17th day post-infection, while in the low concentration group, similar symptoms appeared on the 20th day post-infection and gradually spread to other areas. The scaling symptoms were transient, lasting for 7 days in the high-concentration group and 3 days in the low-concentration group, after which the skin returned to normal. The infection rate was 33.33% in both the high- and low-concentration groups. No significant pathological changes were observed in the skin tissues of infected mice compared to the control group, indicating marked individual differences in the pathogenicity of the strain in nude mice. Conclusion A strain of Staphylococcus xylosus was isolated from the skin of a nude mouse exhibiting squamous skin scurfs. The strain is an opportunistic pathogen that causes transient squamous skin scurfs without significant histopathological changes, and there are individual differences in the sensitivity of nude mice to this strain. These findings can provide valuable data for pathogen identification in immunodeficient or gene knockout mice.

Objective To isolate pathogenic bacteria from the skin of a nude mouse exhibiting squamous skin scurfs, and perform bacterial identification, traceability analysis, and pathogenicity studies to provide a new approach for the diagnosis of pathogens in nude mice with squamous skin scurfs. MethodsSkin swab samples were collected from a nude mouse exhibiting squamous skin scurfs for nucleic acid testing, bacterial isolation and culture, biochemical identification, 16S rDNA gene amplification and sequencing, and whole genome sequencing to construct a phylogenetic tree. Fifteen BALB/c nude mice were randomized into a saline-treated control group, a high-concentration group treated with 1.8×10⁸ CFU/mL of the isolated bacterial suspension, and a low-concentration group treated with 1.8×10⁷ CFU/mL of the isolated bacterial suspension. Pathogenicity was assessed by animal infection experiments and observation of histopathological changes in skin tissue using HE staining. Results The nucleic acid test for Corynebacterium bovis was negative, excluding infection by this organism. The pathogen isolated on mannitol salt agar and blood agar, combined with Gram staining, suggested a Gram-positive Staphylococcus species. The isolated strain was identified by 16S rDNA sequencing and a fully automated microbial identification system as Staphylococcus xylosus. Phylogenetic tree analysis based on whole genome sequencing showed that the strain was most closely related to an isolate from leafy vegetables in South Korea (GenBank GCA_00207825.1). In the high-concentration group, squamous skin scurfs appeared on the head, neck, and back of nude mice on the 17th day post-infection, while in the low concentration group, similar symptoms appeared on the 20th day post-infection and gradually spread to other areas. The scaling symptoms were transient, lasting for 7 days in the high-concentration group and 3 days in the low-concentration group, after which the skin returned to normal. The infection rate was 33.33% in both the high- and low-concentration groups. No significant pathological changes were observed in the skin tissues of infected mice compared to the control group, indicating marked individual differences in the pathogenicity of the strain in nude mice. Conclusion A strain of Staphylococcus xylosus was isolated from the skin of a nude mouse exhibiting squamous skin scurfs. The strain is an opportunistic pathogen that causes transient squamous skin scurfs without significant histopathological changes, and there are individual differences in the sensitivity of nude mice to this strain. These findings can provide valuable data for pathogen identification in immunodeficient or gene knockout mice.

[Objective] To perform genetic analysis on samples with weak agglutination and mixed agglutination of ABO blood group antigens in neonates, and to investigate the molecular biological characteristics of ABO subtypes in neonates. [Methods] Serological identification of ABO blood group was performed by tube method and microcolumn gel method. The ABO exons 2-7 were amplified by PCR, and the amplified products were sequenced by Sanger sequencing method to determine the genotype. [Results] Among the ABO blood group serological results of 14 neonates, 8 cases showed weakened A antigen, and 6 cases showed weakened B antigen. Seven samples were identified with ABO subtype alleles, with genotypes as A102/B101+c.538C>T, Aw26/B102, A205/O02, A205/B101(2 cases), Aw26/O02, B(A)06/O01, B101/O01(3 cases), A102/O01(2 cases), A102/B101 and B101/O02. Additionally, three other family members were also found to carry B(A)06 allele in a pedigree investigation. [Conclusion] For samples showing weakened antigens in ABO blood type identification of neonates, it is necessary to consider the possibility of ABO subtype in addition to age factors, and genetic testing can be used to prevent missed detection of ABO subtypes in neonates.

Objective To establish and evaluate a method for rapid and sensitive S.xylosus detection using qPCR(real-time quantitative PCR).Methods A gehM gene fragment was selected as the target for S.xylosus.A set of specific primers was synthesized and a qPCR method was established to detect S.xylosus.A S.xylosus standard strain and other non-target strains were chosen for analysis.DNA of S.xylosus was diluted 10-fold to determine its sensitivity.Clinical samples were tested,and positive products were sequenced.The result were compared with those of bacterial culture.Results S.xylosus had a specific amplification curve,whereas other non-S.xylosus species did not,indicating that the primers were specific for S.xylosus.Sensitivity was 100 fg/μL DNA.Repeatability within and between groups was less than 3％.A total of 60 clinical samples were analyzed,of which five samples had a typical S curve.qPCR products were sequenced and BLAST searched.The similarity of the gene sequences was 99.63％,indicating that the sample was positive for the S.xylosus gehM gene with a positivity rate of 8.3％.However,the positivity rate of bacterial culture was 6.7％.The positivity rate of qPCR was slightly higher than that of the culture.Conclusions The established qPCR method is rapid with high sensitivity and specificity,and can be used to detect S.xylosus.

Objective To investigate dynamic shifts in the oral microbiota and their association with the progression and aggravation of radiotherapy-induced oral mucositis(RIOM)in patients with head and neck malignancies undergoing radiotherapy.Methods Based on 16S rRNA gene sequencing,dynamic changes of oral microbiota in patients was analyzed.Results Firmicutes,Bacteroidetes,and Actinobacteria consistently constituted the predominant bacteria in the oral cavity.While there were no significant changes in the abso-lute abundance of microbiota,there were notable alterations in their relative richness and evenness.Analyses including CCA/RDA and Kruskal-Wallis indicated a significant increase in the proportions of Streptococcus and Lactobacillus genera in the later stages post-radio-therapy,showing statistically meaningful differences.Conclusion RIOM is associated with dysbiosis of oral microbiota.Microbial dys-biosis may aggravate the severity of RIOM.Streptococcus and Lactobacillus could be closely related to the progression of RIOM,pending further validation through animal experiments.

The microbiological quality of laboratory animals is crucial for the validity and reproducibility of scientific research data,as well as human health and animal welfare.Currently,individual ventilation cages(IVC)have become the mainstream feeding system for rodent laboratory animals.The most commonly used pathogen monitoring method for this feeding system is soiled bedding sentinels(SBS).This method monitors the microbial carrying status of mouse colony through indirect contact and delayed feedback.It can effectively monitor pathogens transmitted via the fecal-oral route,such as mouse hepatitis virus and reovirus.However,this method has difficulty detecting pathogens mainly transmitted through aerosols or direct contact,such as Sendai virus and Pasteurella pneumotropica.The exhaust air dust(EAD)-PCR monitoring method involves swab sampling in the IVC exhaust ducts to monitor the corresponding racks of the ducts;swab sampling before the prefiltration of the host to monitor the entire IVC rack;and EAD collection device sampling to monitor all racks connected to the same host.Different IVC manufacturers have developed corresponding EAD collection devices for their respective IVC systems,making operations convenient and standardization easy.Compared with the SBS method,the EAD-PCR method significantly improves detection rate and timeliness,with the fastest detection possible after one week of exposure.It can serve as a supplement or replacement for the SBS method.Currently,increasing evidence supports that EAD-PCR testing is a more reliable,sensitive,and cost-effective monitoring method,and is more beneficial to animal welfare.This article reviews the application progress of these two methods for monitoring pathogens,analyzes the existing limitations of the EAD-PCR method,and proposes solutions based on its implementation in our laboratory and examination units.The EAD-PCR method helps reduce the number of live sentinel animals used in pathogen monitoring,in order to better maintain the"3Rs"principle of laboratory animal welfare.

Lipid homeostasis is considered to be related to intestinal metabolic balance, while its role in the pathogenesis and treatment of ulcerative colitis (UC) remains largely unexplored. The present study aimed to identify the target lipids related to the occurrence, development and treatment of UC by comparing the lipidomics of UC patients, mice and colonic organoids with the corresponding healthy controls. Here, multi-dimensional lipidomics based on LC-QTOF/MS, LC-MS/MS and iMScope systems were constructed and used to decipher the alteration of lipidomic profiles. The results indicated that UC patients and mice were often accompanied by dysregulation of lipid homeostasis, in which triglycerides and phosphatidylcholines were significantly reduced. Notably, phosphatidylcholine 34:1 (PC34:1) was characterized by high abundance and closely correlation with UC disease. Our results also revealed that down-regulation of PC synthase PCYT1α and Pemt caused by UC modeling was the main factor leading to the reduction of PC34:1, and exogenous PC34:1 could greatly enhance the fumarate level via inhibiting the transformation of glutamate to N-acetylglutamate, thus exerting an anti-UC effect. Collectively, our study not only supplies common technologies and strategies for exploring lipid metabolism in mammals, but also provides opportunities for the discovery of therapeutic agents and biomarkers of UC.

Objective To investigate the effect of H₂O₂-induced oxidative stress on autophagy and apoptosis of human bone marrow mesenchymal stem cells (hBMSCs). Methods hBMSCs were isolated and cultured. The cells were divided into control group, 3-MA group, H₂O₂ group, H₂O₂ combined with 3-MA group. DCFH-DA staining was used to analyze the level of reactive oxygen species (ROS). hBMSCs were treated with 0, 50, 100, 200, 400 μmol/L H₂O₂, and then the cell viability was detected by CCK-8 assay. The level of autophagy was detected by monodansylcadaverine (MDC) staining and LysoTracker Red staining. The cell apoptosis was detected by flow cytometry. Western blotting was used to detect the expression of beclin 1, mTOR, phosphorylated mTOR (p-mTOR), cleaved caspase-3(c-caspase-3) and caspase-3 proteins. Results Compared with the control group and 3-MA group, ROS level and autophagosomes were increased and the proliferation and apoptosis were decreased in H₂O₂ group. The protein expression of beclin 1, mTOR, c-caspase-3 was up-regulated, while the p-mTOR was down-regulated. Compared with the 3-MA group, the H₂O₂ combined with 3-MA group also had an increased ROS level and autophagosomes, but not with significantly increased apoptosis rate; The protein expression of beclin 1, mTOR, c-caspase-3 was up-regulated, and the p-mTOR was down-regulated. Conclusion H₂O₂ can induce hMSCs to trigger oxidative stress response. It enhances the autophagy and inhibits the proliferation and apoptosis of hBMSCs.
Humans ; Beclin-1/metabolism* ; Caspase 3/metabolism* ; Reactive Oxygen Species/metabolism* ; Hydrogen Peroxide/pharmacology* ; Apoptosis ; TOR Serine-Threonine Kinases/metabolism* ; Oxidative Stress ; Autophagy ; Mesenchymal Stem Cells/metabolism* ; Cell Proliferation

BACKGROUND: Sjögren's syndrome (SS) is an autoimmune disorder characterized by sicca syndrome and/or systemic manifestations. The treatment is still challenging. This study aimed to explore the therapeutic role and mechanism of exosomes obtained from the supernatant of stem cells derived from human exfoliated deciduous teeth (SHED-exos) in sialadenitis caused by SS. METHODS: SHED-exos were administered to the submandibular glands (SMGs) of 14-week-old non-obese diabetic (NOD) mice, an animal model of the clinical phase of SS, by local injection or intraductal infusion. The saliva flow rate was measured after pilocarpine intraperitoneal injection in 21-week-old NOD mice. Protein expression was examined by western blot analysis. Exosomal microRNA (miRNAs) were identified by microarray analysis. Paracellular permeability was evaluated by transepithelial electrical resistance measurement. RESULTS: SHED-exos were injected into the SMG of NOD mice and increased saliva secretion. The injected SHED-exos were taken up by glandular epithelial cells, and further increased paracellular permeability mediated by zonula occluden-1 (ZO-1). A total of 180 exosomal miRNAs were identified from SHED-exos, and Kyoto Encyclopedia of Genes and Genomes analysis suggested that the phosphatidylinositol 3 kinase (PI3K)/protein kinase B (Akt) pathway might play an important role. SHED-exos treatment down-regulated phospho-Akt (p-Akt)/Akt, phospho-glycogen synthase kinase 3β (p-GSK-3β)/GSK-3β, and Slug expressions and up-regulated ZO-1 expression in SMGs and SMG-C6 cells. Both the increased ZO-1 expression and paracellular permeability induced by SHED-exos were abolished by insulin-like growth factor 1, a PI3K agonist. Slug bound to the ZO-1 promoter and suppressed its expression. For safer and more effective clinical application, SHED-exos were intraductally infused into the SMGs of NOD mice, and saliva secretion was increased and accompanied by decreased levels of p-Akt/Akt, p-GSK-3β/GSK-3β, and Slug and increased ZO-1 expression. CONCLUSION Local application of SHED-exos in SMGs can ameliorate Sjögren syndrome-induced hyposalivation by increasing the paracellular permeability of glandular epithelial cells through Akt/GSK-3β/Slug pathway-mediated ZO-1 expression.
Mice ; Animals ; Humans ; Sjogren's Syndrome/therapy* ; Proto-Oncogene Proteins c-akt/metabolism* ; Tight Junctions/metabolism* ; Glycogen Synthase Kinase 3 beta ; Mice, Inbred NOD ; Phosphatidylinositol 3-Kinases/metabolism* ; Exosomes/metabolism* ; Xerostomia ; Phosphatidylinositol 3-Kinase ; MicroRNAs/genetics*

Objective:To investigate the application value of 3D printed model in hemostasis training for laparoscopic sleeve gastrectomy.Methods:The retrospective and descriptive study was conducted. Data were collected from six surgeons who participated in hemostasis training for laparoscopic sleeve gastrectomy using 3D printed model at Zhejiang Provincial People′s Hospital in July 2023. All participants were male, aged (33.5±9.9)years. A 3D printed model simulating bleeding during laparoscopic sleeve gastrectomy was created using hydrogel. Videos were recorded to document the surgeons′ hemostasis techniques and outcomes during laparoscopic sleeve gastrectomy. Two external expert reviewers blindly assessed the training videos using the objective structured assess-ment of technical skills (OSATS) scoring system to evaluate mesentery mobilization, vessel exposure, vessel clipping and bleeding after vessel clipping. Observation indicators: (1) face validity and content validity of the 3D printed model; (2) validity verification of the 3D printed model. Measurement data with normal distribution were represented as Mean± SD. Comparison between groups was conducted using the t test. Results:(1) Face validity and content validity of the 3D printed model. The surgeons′ scores for overall impression, fidelity, texture, appearance, workspace and tactile similarity of the 3D printed model were 4.5±0.6, 4.0±0.6, 3.7±0.5, 4.2±0.8, 3.8±0.8 and 4.2±0.4, respectively. The surgeons′ scores for similarity to real scenarios, operation convenience, learning curve shortening and operation skills improving, patient risk reduction, trainee′s interest enhancing, confidence increasing and recommendation for promotion were 4.0±0.6, 4.2±0.8, 4.3±0.8, 4.3±0.5, 4.3±0.5, 4.0±0.6 and 4.8±0.4, respectively. (2) Validity verification of the 3D printed model. The OSATS scores and operation time to treat bleeding during laparoscopic sleeve gastrectomy for expert surgeons were 18.7±0.6 and (125±12)seconds, respectively, versus 13.7±1.5 and (212±51)seconds for junior doctors, showing significant differences between the two groups ( t=5.30, -2.89, P<0.05). Conclusion:The 3D printed model effectively simulates bleeding scenarios during laparoscopic sleeve gastrectomy and distinguishes between different technical levels of expertise.