AIM:To investigate the mechanism by which muscle segment homeobox 2(Msx2)regulates the differentiation of outer enamel epithelial cells in the enamel organ.METHODS:Tissue paraffin sections were prepared and subjected to hematoxylin-eosin(HE)staining to analyze the effect of Msx2 deficiency on the differentiation status of epithelial cells in the enamel organ at the morphological level.At the ultrastructural level,alterations in cell structure were analyzed.The intermediate steps mediating cell differentiation were identified.Transcriptome sequencing analysis was performed to validate the molecular mechanisms underlying the observed phenomena.RESULTS:Msx2 deficiency was innovatively found to induce severe squamous epithelial hyperplasia in outer enamel epithelial cells of enamel organ,accompanied by dynamic restructuring of the cell cytoskeleton and alterations in cell adhesion at the ultrastructure level.As a transcriptional repressor,the loss of Msx2 expression results in significant increases(P＜0.05 or P＜0.01)in the mRNA expression levels of integrin β2(Itgβ2),ItgαM,Itgα4,Rac family small GTPase 2(Rac2),Rac/Cdc42 guanine nucleo-tide exchange factor 6(Arhgef6)and protein tyrosine phosphatase receptor type C(Ptprc).CONCLUSION:Msx2 regu-lates cytoskeleton structure and cell-cell interaction through the Rho GTPases signaling pathway,thereby influencing the differentiation state of outer enamel epithelial cells.This study reveals the mechanism through which Msx2 regulates the differentiation of outer enamel epithelial cells,providing a theoretical foundation for the prevention and treatment of enam-el-related clinical dental diseases.

AIM:To investigate the mechanism by which muscle segment homeobox 2(Msx2)regulates the differentiation of outer enamel epithelial cells in the enamel organ.METHODS:Tissue paraffin sections were prepared and subjected to hematoxylin-eosin(HE)staining to analyze the effect of Msx2 deficiency on the differentiation status of epithelial cells in the enamel organ at the morphological level.At the ultrastructural level,alterations in cell structure were analyzed.The intermediate steps mediating cell differentiation were identified.Transcriptome sequencing analysis was performed to validate the molecular mechanisms underlying the observed phenomena.RESULTS:Msx2 deficiency was innovatively found to induce severe squamous epithelial hyperplasia in outer enamel epithelial cells of enamel organ,accompanied by dynamic restructuring of the cell cytoskeleton and alterations in cell adhesion at the ultrastructure level.As a transcriptional repressor,the loss of Msx2 expression results in significant increases(P＜0.05 or P＜0.01)in the mRNA expression levels of integrin β2(Itgβ2),ItgαM,Itgα4,Rac family small GTPase 2(Rac2),Rac/Cdc42 guanine nucleo-tide exchange factor 6(Arhgef6)and protein tyrosine phosphatase receptor type C(Ptprc).CONCLUSION:Msx2 regu-lates cytoskeleton structure and cell-cell interaction through the Rho GTPases signaling pathway,thereby influencing the differentiation state of outer enamel epithelial cells.This study reveals the mechanism through which Msx2 regulates the differentiation of outer enamel epithelial cells,providing a theoretical foundation for the prevention and treatment of enam-el-related clinical dental diseases.

Objective To investigate the therapeutic effects of bone marrow mesenchymal stem cells (BMSCs) for radiation-induced lung injury (RILI) and the underlying mechanism. Methods Forty-five healthy adult male C57BL/6 mice were randomly divided into control, model, and BMSCs groups. The model and BMSCs groups received a single irradiation dose of 20 Gy to the chest, while the control group did not receive X-ray irradiation. For the BMSCs group, an injection of 1 × 10⁶ BMSCs cells was administered via the tail vein within 6 h after irradiation. In the 5th week, the lung tissue was taken to observe pathological changes with HE staining; examine the expression of the inflammatory factors interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) with immunohistochemical staining; observe the polarization of macrophages with immunofluorescence staining; and measure the expression of the epithelial-mesenchymal transition markers E-cadherin, N-cadherin, and vimentin proteins by Western blot. Results After radiation, the model group developed pulmonary vasodilation and congestion with septal thickening and inflammatory cell infiltration, and these changes were markedly reduced in the BMSCs group. The model group showed significantly down-regulated expression of IL-6 and TNF-α compared with significantly increased levels in the model group (P < 0.01, P < 0.05). Treatment with BMSCs significantly increased the polarization of lung macrophages towards the M2 type, while significantly decreasing the abnormally increased N-cadherin and vimentin levels in RILI mice (P < 0.05, P < 0.01). Conclusion BMSCs have therapeutic effects for RILI mice, which may be through promoting macrophage polarization from M1 to M2.

Colorectal cancer is one of the common malignant tumors of the digestive tract.With the popularization of screening methods and advancement of endoscopic technology,an increasing number of T1 stage colorectal cancers can be discovered.Accurately predicting lymph node metastasis risk is significantly important for guiding clinical treatment decisions,reducing complications and mortality.Current research on risk factors for lymph node metastasis in T1 stage colorectal cancer covers multiple aspects including clinical pathological features,molecular phenotypes and genetic characteristics.Some studies have built prediction models by integrating these factors,which show higher sensitivity,specificity and accuracy compared to current clinical guidelines.These models provide valuable experience for clinical practice.

BACKGROUND: Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome is a severe congenital disorder characterized by vaginal hypoplasia caused by dysplasia of the Müllerian duct. Patients with MRKH syndrome often require nonsurgical or surgical treatment to achieve satisfactory vaginal length and sexual outcomes. The extracellular matrix has been successfully used for vaginal reconstruction. METHODS: In this study, we developed a new biological material derived from porcine vagina (acellular vaginal matrix, AVM) to reconstruct the vagina in Bama miniature pigs. The histological characteristics and efficacy of acellularization of AVM were evaluated, and AVM was subsequently transplanted into Bama miniature pigs to reconstruct the vaginas. RESULTS: Macroscopic analysis showed that the neovaginas functioned well in all Bama miniature pigs with AVM implants. Histological analysis and electrophysiological evidence indicated that morphological and functional recovery was restored in normal vaginal tissues. Scanning electron microscopy showed that the neovaginas had mucosal folds characteristics of normal vagina. No significant differences were observed in the expression of CK14, HSP47, and a-actin between the neovaginas and normal vaginal tissues. However, the expression of estrogen receptor (ER) was significantly lower in the neovaginas than in normal vaginal tissues. In addition, AVM promoted the expression of b-catenin, c-Myc, and cyclin D1. These results suggest that AVM might promotes vaginal regeneration by activating the b-catenin/cMyc/cyclin D1 pathway. CONCLUSION This study reveals that porcine-derived AVM has potential application for vaginal regeneration.

Covalent organic nanospheres(CONs)were explored as a fiber coating for solid-phase microextraction of genotoxic impurities(GTIs)from active ingredients(AIs).CONs were synthesized by an easy solution-phase procedure at 25℃.The obtained nanospheres exhibited a high specific surface area,good ther-mostability,high acid and alkali resistance,and favorable crystallinity and porosity.Two types of GTIs,alkyl halides(1-iodooctane,1-chlorobenzene,1-bromododecane,1,2-dichlorobenzene,1-bromooctane,1-chlorohexane,and 1,8-dibromooctane)and sulfonate esters(methyl p-toluenesulfonate and ethyl p-toluenesulfonate),were chosen as target molecules for assessing the performance of the coating.The prepared coating achieved high enhancement factors(5097-9799)for the selected GTIs.The strong affinity between CONs and GTIs was tentatively attributed to T-T and hydrophobicity interactions,large surface area of the CONs,and size-matching of the materials.Combined with gas chromatography-mass spectrometry(GC-MS),the established analytical method detected the GTIs in capecitabine and imatinib mesylate samples over a wide linear range(0.2-200 ng/g)with a low detection limit(0.04-2.0 ng/g),satisfactory recovery(80.03％-109.5％),and high repeatability(6.20％-14.8％)and reproducibility(6.20％-14.1％).Therefore,the CON-coated fibers are promising alternatives for the sensitive detection of GTIs in AI samples.

Ex vivo-expanded mesenchymal stem cells(MSCs)have been demonstrated to be a heterogeneous mixture of cells exhibiting varying proliferative,multipotential,and immunomodu-latory capacities.However,the exact characteristics of MSCs remain largely unknown.By single-cell RNA sequencing of 61,296 MSCs derived from bone marrow and Wharton's jelly,we revealed five distinct subpopulations.The developmental trajectory of these five MSC subpopulations was mapped,revealing a differentiation path from stem-like active proliferative cells(APCs)to multipotent progenitor cells,followed by branching into two paths:1)unipotent preadipocytes or 2)bipotent prechondro-osteoblasts that were subsequently differentiated into unipotent prechondro-cytes.The stem-like APCs,expressing the perivascular mesodermal progenitor markers CSPG4/MCAM/NES,uniquely exhibited strong proliferation and stemness signatures.Remarkably,the prechondrocyte subpopulation specifically expressed immunomodulatory genes and was able to sup-press activated CD3+T cell proliferation in vitro,supporting the role of this population in immunoregulation.In summary,our analysis mapped the heterogeneous subpopulations of MSCs and identified two subpopulations with potential functions in self-renewal and immunoregulation.Our findings advance the definition of MSCs by identifying the specific functions of their heteroge-neous cellular composition,allowing for more specific and effective MSC application through the purification of their functional subpopulations.

OBJECTIVE： To prepare Zingiber officinale oil microcapsules and to evaluate its quality. METHODS： Z. officinale oil microcapsules were prepared by spray drying method with sodium starch octenyl succinate as capsule material. The preparation technology was optimized by orthogonal test with mixing temperature of capsule material and capsule core， mass ratio of capsule material and capsule core， stirring speed as factors， using encapsulation efficiency as index. The drug loading， encapsulation efficiency， appearance， particle size distribution and stability of light， heat and humidity （using iodine value and peroxide value as indexes） were evaluated. RESULTS： The optimal preparation technology of Z. officinale oil microcapsules was that the mixing temperature of capsule material and core was 60 ℃； mass ratio of capsule material and capsule core was 10 ∶ 1； stirring speed was 12 000 r/min. Average drug-loading amount and encapsulation efficiency of Z. officinale oil microcapsules prepared by optimal technology were 17.97％ and 73.57％ （n＝3）. The morphology of Z. officinale oil microcapsules was round， smooth， non-sticky and uniform in size distribution. The average diameter of microcapsules was （6.30±0.27） μm. Under light， heat and humidity conditions， the iodine value and peroxide value of Z. officinale oil microcapsules changed slightly. CONCLUSIONS： The optimal preparation technology of Z. officinale oil microcapsules is simple and reproducible. The prepared microcapsules have good encapsulation efficiency， high drug loading amount and good stability.

Objective To explore and analyze the clinical characteristics of extremely premature infants at low risk for early-onset sepsis (EOS) , so as to avoid overuse of antibiotics. Method The clinical data of extremely premature infants hospitalized from January 1, 2010 to December 31, 2017 were collected. Extremely premature infants born from mothers without premature rupture of membranes and without maternal clinical manifestations of chorioamnionitis during pregnancy were classified assigned into the low-risk group, and those who did not meet the low-risk conditions were regarded assigned intoas the control group. EOS was diagnosed according to the results of blood culture within 72 hours after birth. The clinical characteristics, treatment and outcome of extremely premature infants between the two groups were retrospectively analyzed. Results A total of 245 extremely preterm infants were enrolled, including 153 (62.4％) in low-risk group. Compared with the control group, mothers in low-risk group had higher rates of gestational diabetes and hypertension, higher rates of antenatal hormone use and lower rates of antenatal antibiotics use; furthermore, neonates in low-risk group had lower rates of Apgar score ＜ 5, higher rates of pulmonary surfactant use, respiratory support and mechanical ventilation, and lower risk of death and incidence of early-onset sepsis. The differences were statistically significant (P＜0.05) . Among In extremely premature infants whose having survival time＞ 24 hours, compared with control group, infants in low-risk group had higher incidences of respiratory distress syndrome, patent ductus arteriosus, intracranial hemorrhage and bronchopulmonary dysplasia, and lower incidence of pulmonary hemorrhage than control group, and the differences were statistically significant (all P＜0.05) . In low-risk group, the risks of death, respiratory distress syndrome, pulmonary hemorrhage and bronchopulmonary hemorrhage in long-term antibiotic group were higher than the short-term antibiotic group. Conclusion Early identification of extremely preterm infants at low risk of early-onset sepsis in extremely preterm infants is of clinical significance in reducing early empirical use of antibiotics therapy.

Neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) is an autosomal recessive disease caused by SLC25A13 gene mutations, and is characterized by delayed jaundice clearance, liver dysfunction, and elevated aminoacidemia. The confirmed diagnosis depends on gene analysis. Citrin deficiency is one of the important causes of neonatal intrahepatic cholestasis in China. Recently more and more researches about NICCD were reported. The paper summarized the epidemiology, pathogenesis, clinical characteristics, and progresses in diagnosis and treatment of NICCD.