Objective To investigate the effects of fractionated low-dose ionizing radiation (LDIR) on the ferroptosis in human bronchial epithelial (HBE) cells as well as the associated differentially expressed genes (DEGs), biological processes, and signaling pathways. Methods HBE cells were exposed to different single doses of X-ray irradiation (0, 25, 50, 75, and 100 mGy) for 24, 48, and 72 h, respectively. The change in cell viability was detected by MTT assay. Cells were irradiated with 0, 25, 50, and 100 mGy X-rays 5 times, with 48 h between each irradiation and a dose rate of 50 mGy/min. Cells were harvested 24 h after irradiation for the measurement of the expression of ferroptosis-related genes SLC7A11 and GPX4 at the mRNA and protein levels, cellular iron content, and the expression of FTH1 and FTL mRNAs. High-throughput sequencing was used to screen for the DEGs in each dose group, followed by Gene Ontology-Biological Process (GO-BP) analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, and Gene Set Enrichment Analysis (GSEA). Results Compared with the control group, single-dose LDIR significantly increased cell proliferation at 75 mGy after 24 h (P < 0.05), at 50, 75, and 100 mGy after 48 h (P < 0.05), and at 75 and 100 mGy after 72 h (P < 0.05). Compared with the control group, at the end of the fifth fractionated LDIR, SLC7A11 and GPX4 mRNAs decreased at all doses (P < 0.05), SLC7A11 protein decreased at all doses, GPX4 protein decreased at 25 and 100 mGy, iron content increased at all doses, and FTH1 and FTL mRNAs decreased at all doses (P< 0.05). Sequencing analysis identified 248, 30, and 291 DEGs and 10, 2, and 9 ferroptosis-associated genes at the three doses compared to the control. Gene Ontology-Biological Process analysis showed that DEGs were mainly enriched in biological processes such as response to lipids, cell death, and response to unfolded proteins. Kyoto Encyclopedia of Genes and Genomes analysis showed that DEGs were mainly enriched in the JAK-STAT signaling pathway, lipids and atherosclerosis, ferroptosis, protein processing in the endoplasmic reticulum, and FoxO signaling pathway. Gene set enrichment analysis showed that DEGs were mainly enriched in ferroptosis, fatty acid degradation, and glutathione metabolism. Conclusion Fractionated low-dose radiation induced ferroptosis in HBE cells, and DEGs were predominantly enriched in biological processes and signaling pathways related to inflammation, ferroptosis, and endoplasmic reticulum stress.

Objective To investigate the role of the O-6-methylguanine-DNA methyltransferase (MGMT) gene-3′ untranslated region (UTR) microRNA-associated single nucleotide polymorphism (miRSNP) (rs7896488 G>A) in affecting miR-4297-targeted modulation of MGMT in senescence of lung cells with polymorphic genotypes induced by fractionated low dose ionizing radiation (LDIR). Methods i) MiRSNPs were predicted and screened using bioinformatics, and DNA from two types of lung cells, A549 cells and human bronchial epithelioid cells (HBE cells), was extracted for target gene sequencing. After co-transfection of pGL3c-MGMT-3′UTR-rs7896488 G>A reporter gene recombinant plasmid, pRL-TK Vector with micrON mimic NC #22 or micrON hsa-miR-4297 mimic (set up as the mimic NC group and the miR-4297 mimic group) in these two types of lung cells, dual luciferase reporter gene assay was performed. The relative expression of MGMT mRNA was detected by real-time fluorescence quantitative polymerase chain reaction, and the relative expression of MGMT protein was detected by Western blotting. ii) These two types of lung cells were randomly divided into the control group and irradiation group, which received either 0 or 100 mGy X-rays irradiation seven times. After irradiation, the cells were transfected with either micrON mimic NC #22 or micrON hsa-miR-4297 mimic, resulting in mimic NC + control group, miR-4297 mimic + control group, mimic NC + irradiation group, and miR-4297 mimic + irradiation group. Cells were collected for senescence-associated-β-galactosidase (SA-β-Gal) staining, and the relative expression of matrix metalloproteinase-9 (MMP-9) and chemokine (C-X-C motif) ligand-1 (CXCL-1) proteins was detected via Western blotting. Results i) The rs7896488 G>A was the miRSNP located in the conserved binding region targeted by miR-4297 in the MGMT gene 3′UTR. A549 cells were the rs7896488 GG wild-type homozygous genotype, while HBE cells were the rs7896488 GA heterozygous mutant genotype. In the miR-4297 mimic group, A549 and HBE cells carrying the rs7896488 G allele showed significantly lower dual-luciferase activity compared with that in the mimic NC group (both P<0.01). However, there was no significant difference in dual-luciferase activity between the two groups in both A549 and HBE cells carrying the rs7896488 A allele (both P>0.05). The relative expression levels of MGMT mRNA and MGMT protein of A549 cells in the miR-4297 mimic group were lower than those in the mimic NC group (both P<0.05). However, there was no significant difference in MGMT mRNA and MGMT protein of HBE cells between these two groups (both P>0.05). ii) The relative activity of SA-β-Gal and the relative expression of MMP-9 and CXCL-1 proteins of A549 cells in the miR-4297 mimic+irradiation group were higher than those in the mimic NC + control group, the miR-4297 mimic + control group, and the mimic NC + irradiation group (all P<0.05). The relative activity of SA-β-Gal and the relative expression of MMP-9 and CXCL-1 proteins of HBE cells in the miR-4297 mimic + irradiation group were higher than those in the mimic NC + control group and the miR-4297 mimic + control group (all P<0.05), while there was no significant difference compared with those in the mimic NC + irradiation group (all P>0.05). Conclusion MGMT-3′UTR-miRSNP rs7896488 G>A plays a role in LDIR-induced senescence of lung cells with different polymorphic genotypes by affecting miR-4297-targeted regulation of MGMT.

Background In recent years, the increasingly widespread application of nuclear and medical radiation technologies has resulted in a large number of occupational populations exposed to low-dose ionizing radiation (LDIR). At present, there is no consistent conclusion on the effects of long-term exposure to LDIR on the metabolic health of the occupational population. Objective To explore the association between long-term exposure to LDIR and metabolic syndrome (MetS) among medical radiologists. Methods A cross-sectional study was conducted to enroll 6431 medical radiologists who ordered occupational health checkups from January 2022 to December 2023, and basic information such as demographic characteristics, occupational characteristics, lifestyles, and dietary habits was collected through questionnaires. Physical examinations were conducted using a standardized protocol. Individual dose equivalents of occupational external exposure were monitored by dosimeters worn by medical radiologists. Logistic regression model was used for identifying influencing factors of MetS and sensitivity analysis, and restricted cubic spline model was used to explore the dose-response relationship between cumulative effective dose and MetS. Two-stage linear regression was used to evaluate threshold effect of association between cumulative effective dose and MetS. Results The positive rate of MetS was 13.6% (877/6431) among the enrolled 6431 study participants. The logistic regression showed that gender, age, monthly income, body mass index (BMI), cumulative effective dose, and smoking were influencing factors for MetS. The risk of MetS was higher in males (OR=1.511, 95%CI: 1.209, 1.888); using the < 30 years old group as reference, the risk of MetS was higher in the 30-39 years old (OR=1.509, 95%CI: 1.095, 2.079), 40-49 years old (OR=2.214, 95%CI: 1.551, 3.161), and ≥50 years old (OR=3.480, 95%CI: 2.338, 5.181) groups; using the <10000 yuan group as reference, the risk of MetS was lower in the group with a monthly income of 10000-14999 yuan (OR=0.715, 95%CI: 0.582, 0.878); the risk of MetS was higher in the BMI ≥ 24 kg·m⁻² group (OR=7.548, 95%CI: 6.223, 9.156); using the < 0.76 mSv group as reference, the risk of MetS was higher in the cumulative effective dose of 0.76-2.73 mSv group (OR=1.270, 95%CI: 1.017, 1.586); the risk of MetS was higher in the smoking group (OR=1.734, 95%CI: 1.428, 2.107). The results of restricted cubic spline showed that the cumulative effective dose was nonlinearly correlated with MetS (P _{non-linearity}=0.028), with an inflection point of 1.25 mSv. The risk of developing MetS increased by 34.1% for each unit increase in cumulative effective dose up to 1.25 mSv, whereas above 1.25 mSv, the statistical association was not significant. The sensitivity analysis results showed that after excluding the self-reported hypertensive and diabetic patients, the cumulative effective dose 0.76-2.73 mSv group still had an increased risk of developing MetS compared with the < 0.76 mSv group (P < 0.05), and the results were robust. Conclusion Among medical radiologists, male, age, BMI, and smoking are positively correlated with MetS, and monthly income is negatively correlated with MetS; cumulative effective dose is non-linearly correlated with MetS among medical radiologists.

Checkpoint blockade immunotherapy has emerged as a transformative approach in cancer treatment by activating tumor-infiltrating T cells. However, the efficacy of PD-L1 blockade is restricted in "cold" tumors, which are characterized by low immunogenicity, presenting a challenge to immunotherapy. This study introduces an innovative strategy, utilizing cathepsin-cleavable N-(2-hydroxypropyl) methacrylamide (HPMA) polymer-assisted combined photodynamic therapy (PDT) and PD-L1 degradation for the first time, effectively treating T cell-deficient tumors. The degradable main-chain polymer, conjugated with photosensitizer porphyrin, facilitates the accumulation of reactive oxygen species (ROS), triggering immunogenic cell death (ICD) and promoting cytotoxic T lymphocytes (CTLs) infiltration into tumors. Multivalent peptide antagonists of PD-L1 promote PD-L1 degradation in lysosomes through receptor crosslinking, overcoming the adaptive cycling of PD-L1 to the tumor cell surface. These findings demonstrate that polymer-assisted PDT and PD-L1 crosslinking degradation represent a potential novel strategy for anti-tumor immunotherapy, providing valuable tools for expanding immunotherapy applications in immunosuppressive cancers.

Objective To study the differences in features of event-related potentials(ERPs)and target detection accuracy between five brain regions(frontal,temporal,central,parietal,and occipital)in target detection tasks based on rapid serial visual presentation(RSVP)brain computer interface(BCI)under six target concealment conditions.Methods Twelve participants were selected for the study,whose scalp electroencephalogram(EEG)signals were collected under the six concealment conditions using a NeuroScan SynAmps2 EEG acquisition system.The ERP waveforms,P300 amplitudes and latencies,among other things,were compared across the five brain regions.The hierarchical discriminant component analysis(HDCA)algorithm was used to classify the EEG signals while the differences in classification accuracy were probed across the five brain regions.Results(1)Under the six concealment conditions,target images elicited distinct ERP waveforms in all the five brain regions;(2)For P300 amplitudes,the temporal region exhibited the smallest values;(3)Regarding P300 latencies,the parietal and central regions showed longer durations than other brain regions(except for small camouflage and small occlusion conditions);(4)In terms of classification accuracy,the parietal and central regions outperformed other brain regions(except for the large camouflage condition).Conclusion The selection of parietal and central channels can offer a new perspective for enhancing the performance in concealed target detection based on RSVP-BCI,and is expected to spark new ideas for the design of miniaturized,simple and wearable BCI devices.

Objective To explore an overcorrection quantization method and related influencing factors through analyzing relationships between the achieved and preset intrusion values of mandibular anterior teeth with clear aligners.Methods Twenty pa-tients receiving Invisalign were recruited.The relative intrusion values in the ClinCheck software were recorded as the preset intrusion.The achieved intrusion values were measured through the digital model superimposition.Statistical analysis was conducted to assess the differences and linear relationships between the preset and achieved intrusion values,and investigate the effect of related factors such as intrusion amounts on the intrusion efficiency.Results For the mandibular anterior teeth,the mean intrusion efficiency was 62.2%,with the highest in the central incisors and the lowest in the canines.The intrusion amounts,incisors labial inclinations,and canine at-tachment types affected the intrusion efficiency.The differences between the preset and achieved values were significant,and the linear relationship existed.The formula of the intrusion overcorrection for the mandibular anterior teeth is"Z=(W-0.110)/0.533-W".Z re-presents the overcorrection and W represents the ideal intrusion.Conclusion The preset intrusion values in the treatment protocol could not be fully achieved.Moreover,correction should be designed in cases of mandibular canine intrusion,large amountsof intru-sion,orlingually inclined incisors.Compared to the optimized attachments,the vertical rectangular attachments on the mandibular ca-nines could improve the efficiency.

Objective To evaluate and compare the treatment efficacy between concentrated growth factor(CGF)and blood clots(BC)as scaffolds in regenerative endodontic procedures(REPs).Methods Twenty young permanent teeth from 18 healthy children with pulp necrosis or periapical periodontitis were randomly divided into CGF group and BC group.In the CGF group(n=10),after ap-ical bleeding,CGF was inserted into the root canal as a stent.In the BC group(n=10),by stimulating apical bleeding,blood entered the root canal and produced blood clots as scaffolds.Clinical examination and apical X-ray shooting were conducted for each follow-up visit.Cone beam computed tomographic(CBCT)images were acquired preoperatively and at the 24-month recall.The increase of root length,root wall thickness,and newly-formed calcified tissue were calculated.Results The root length increased by(1.68±0.90)mm in the CGF group and(2.36±1.34)mm in the BC group.Root wall thickness increased by(0.44±0.34)mm in the CGF group and(0.50±0.31)mm in the BC group.There was no statistically significant difference in root lengthening and root wall thickening between two groups(P＞0.05).The amount of newly formed calcified tissue in the CGF group((22.13±19.12)mm3)was significantly less than that in the BC group((42.97±22.69)mm3)(P＜0.05).According to the goals for success outlined by American Association of Endodontists(AAE),90%(9/10)of the CGF cases and100%(10/10)of the BC cases achieved the primary and secondary goals(P＞0.05).40%of the CGF cases(4/10)and 60%of the BC cases(6/10)achieved the tertiary goal(P＞0.05).Conclusion CGF is found to be use-ful as a scaffold for REPs,but the success rate is slightly lower than that of BC group and the difference is not statistically significant.

Objective To explore the effect of melatonin(MT)-modified PEEK implant assisted by polydopamine(PDA)coating on osteointegration in osteoporotic rats.Methods MT was adhered to PEEK implants with PDA coating as carrier.The physicochemical properties of the materials were analyzed by SEM image,water contact angle,FTIR and protein adsorption experiment.OVX-rBMSCs were inoculated on the surface of PEEK sheet and cultured.The cytoskeleton was stained and cell adhesion morphology was observed.Cell proliferation activity was evaluated by CCK-8 assay;key enzyme activities for osteogenic differentiation were analyzed by ALP stai-ning,and expression levels of osteoblast-related genes COL-1,Runx2,OPN,OCN,BMP-2 and ALP were detected by quantitative real-time PCR.In addition,implants were implanted into the femur of osteoporotic rats and bone volume on the implant surface was de-tected and quantified by Micro-CT.Results MT was successfully loaded on PEEK;the cell adhesion was better,and the proliferation activity and osteogenic differentiation ability were significantly higher than those of control group(P＜0.01).In the rat osteoporosis mod-el,there was more new bone formation around the modified PEEK implant(P＜0.01).Conclusion MT-modified PEEK implants have excellent biocompatibility and improve osteointegration in an osteoporotic environment.

Objective To measure the anatomical parameters of the first maxillary molars in children of different age groups and evaluate the age-related changes in dental crowns.Methods A retrospective analysis was conduc-ted on cone beam computed tomography(CBCT)images of 4-8-year-old children.NNT software was used to ana-lyze multiple important indicators of maxillary first molar.Results A total of 308 first maxillary molars,including 154 pediatric patients,were evaluated in this study.The thickness of the pulp apex H1(left,P=0.01;right,P=0.02)and the thickness of the pulp chamber floor H3(left and right P＜0.01)were positively correlated with age,while the height of the pulp cavity H2(left and right P＜0.01)and the height of the palate tip D1(left P=0.003,right P=0.002)showed a negative correlation with age.There was no significant correlation between the height of the buccal tip and age(P＞0.05).There were significant differences in H1 and H3 between the 4-year-old and 5-year-old age groups between the 8-year-old age group(P＜0.05),as well as significant differences in H2 and D1 between the 4-year-old and 5-year-old between the 6-year-old,7-year-old and 8-year-old age groups(P＜0.05).Conclusion The age-related changes in the crowns of the first maxillary molars are important references for the clinical treatment,and can be accurately measured through CBCT data.

BACKGROUND:Sema3A is a power secretory osteoprotective factor.However,studies about Sema3A-modified dental pulp stem cells(Sema3A-DPSCs)are rare. OBJECTIVE:To explore the osteogenic differentiation ability of Sema3A-DPSCs and their regulatory effect on the osteogenic differentiation of the pre-osteoblast cell line MC3T3-E1. METHODS:First,Sema3A-DPSCs were constructed using a lentivirus infection system carrying the Sema3A gene.Control lentivirus-treated DPSCs(Vector-DPSCs)were used as controls.Sema3A-DPSCs or Vector-DPSCs were co-cultured with proosteoblast line MC3T3-E1 at the ratio of 1∶1 and 1∶3 for 24 hours.Finally,the Sema3A-DPSCs,Vector-DPSCs and their co-cultured cells with MC3T3-E1 were cultured for osteogenic induction and differentiation.Osteogenic gene expression was detected by alkaline phosphatase staining,alizarin red staining and real-time quantitative RT-PCR to evaluate osteogenic differentiation ability. RESULTS AND CONCLUSION:(1)Sema3A mRNA and protein expression levels in Sema3A-DPSCs were significantly up-regulated.The level of secreted Sema3A in cell supernatant was up-regulated.(2)Compared with the Vector-DPSCs,mRNA expressions of osteogenic genes alkaline phosphatase,Runt-related transcription factor 2,osteocalcin and Sp7 transcription factors in Sema3A-DPSCs were up-regulated;the activity of alkaline phosphatase was enhanced,and the formation of mineralized nodules increased.(3)There were no obvious differences in proliferation between Sema3A-DPSCs and Vector-DPSCs.(4)Compared with MC3T3-E1/Vector-DPSCs co-culture system,the expression of MC3T3-E1 osteogenic genes was up-regulated,and the total alkaline phosphatase activity was enhanced and more mineralized nodules were formed in the MC3T3-E1/Sema3A-DPSCs co-culture system.(5)The results suggest that overexpression of Sema3A can enhance the osteogenic differentiation of DPSCs.Overexpression of Sema3A in DPSCs can promote osteogenic differentiation of MC3T3-E1 in the DPSCs/MC3T3-E1 co-culture system.