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.

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 explore the differentially expressed mRNAs and related biological processes and pathways in fractional low-dose ionizing radiation (LDIR)-induced senescence of normal human bronchial epithelial (HBE) cells by high-throughput mRNA sequencing and bioinformatics techniques. Methods Senescence-associated β-galactosidase staining and senescence-associated secretion phenotype gene mRNA and protein expression levels were measured at 24 and 48 h after irradiating HBE cells 7 times at doses of 0, 50, 100, and 200 mGy, respectively. The differentially expressed genes were screened by high-throughput sequencing for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. Results The senescence-positive area of fractional low-dose irradiated HBE cells increased in a dose-dependent manner (P < 0.05). The mRNA levels and protein expression of transforming growth factor-β1(TGF-β1) and matrix metalloproteinase-9(MMP-9) genes were increased in the 100 mGy × 7 and 200 mGy × 7 groups at 24 and 48 h after the end of irradiation compared with the control group. High-throughput sequencing showed that there were 882, 475, and 1205 differentially expressed mRNAs in each dose group compared with the control group. GO analysis showed that the differentially expressed mRNAs in each dose group were mainly enriched in biological processes such as cell cycle regulation, regulation of nitrogen compound metabolic process, regulation of cell division and response to stimulus. KEGG analysis showed that the differentially expressed mRNAs were mainly enriched in the pathways of cell cycle, cell senescence, and ferroptosis. Conclusion Fractional LDIR induced senescence in HBE cells, and differentially expressed mRNA-associated biological processes and pathways in senescent cells are related to cell cycle and cell senescence.

Objective To investigate the mechanism of fractionated low-dose ionizing radiation (LDIR) in the induction of EA.hy926 cell senescence. Methods EA.hy926 cells were irradiated with X-ray at 0, 50, 100, and 200 mGy × 4, respectively, and cultured for 24, 48, and 72 h. Several indicators were measured, including the levels of cellular senescence-associated β-galactosidase (SA-β-gal) staining, mRNA levels of senescence-associated cell cycle protein-dependent kinase inhibitor genes CDKN1A and CDKN2A, reactive oxygen species (ROS), total antioxidant capacity (T-AOC), and phosphorylated H2A histone family member X (γ-H2AX). Results After 4 fractionated LDIR, compared with the control group, the treatment groups showed increased nucleus area, blurred cell edge, and increased SA-β-gal positive area (P < 0.05) at 24, 48 and 72 h. After 4 fractionated LDIR, the mRNA level of CDKN1A increased in the 100 and 200 mGy × 4 groups at 24 and 48 h (P < 0.05), and CDKN2A mRNA level increased in the 100 and 200 mGy × 4 groups at 48 and 72 h (P < 0.05). The fluorescence intensity of ROS increased in treatment groups at 24, 48, and 72 h after 4 fractionated LDIR (P < 0.05). After 4 fractionated LDIR, the T-AOC level increased in the 100 and 200 mGy × 4 groups at 24 h (P < 0.05), and T-AOC level increased in all treatment groups at 48 and 72 h (P < 0.05). After 4 fractionated LDIR, γ-H2AX fluorescence intensity increased in all treatment groups at 24 h (P < 0.05), and the fluorescence intensity increased in the 100 and 200 mGy × 4 groups at 48 and 72 h (P < 0.05). Conclusion Fractionated LDIR can induce cellular senescence in EA.hy926 cells by impacting the cellular oxidation-antioxidation and oxidative damage levels, and the effects were relatively evident at 100 and 200 mGy.

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.

Taking the current situation and problems of medical humanities education as the background, the concept of narrative medicine was used to sort out and integrate various course materials of medical humanities, explore the multi-link linkage mode of medical humanities education, and organically integrate medical humanities courses scattered in medical education activities such as medical ethics, health law, doctor-patient communication, and health policy science with teaching stages, teaching resources, and teaching methods, forming vivid narrative medical materials throughout the entire process of medical humanities education, and improving teaching efficiency by sharing and optimizing resources. Through questionnaire analysis, it was found that there are many unsatisfactory aspects of medical humanities education. Further analysis of the issues focuses on the contradiction between learning willingness and time allocation, the lack of synchronization between teaching and social development, the lack of integration between courses, and insufficient innovation in teaching methods. Based on these, countermeasures were put forward to integrate narrative medical materials of medical humanities courses and build a platform for the application and communication of narrative medical materials.

Improveing students’ strain capacity in the application of medical ethics is an important part of clinical teaching. This paper revealed the basic connotation of strain capacity in the application of medical ethics, emphasized the necessity for medical students to possess this quality, and emphatically expounded that training students in clinical teaching according to the five basic practical requirements of ethical adaptability. For practical problems, students’ ethical discrimination ability, ethical difficult problem handling ability, and comprehensive application ability of ethics and law should be improved according to practical requirements.

Objective:To investigate the application value of modified through-suture T-tube in laparoscopic biliary tract surgery.Methods:The retrospective and descriptive study was constructed. The clinical data of 15 patients with cholecystolithiasis and choledocholithiasis who underwent laparoscopic biliary tract surgery in China-Japan Friendship Hospital of Jilin University from January to December 2022 were collected. There were 8 males and 7 females, aged (49± 14)years. Of 15 patients, 8 cases undergoing laparoscopic cholecystectomy + common bile duct exploration and lithotomy+conventional T-tube drainage were set as conventional group and 7 cases undergoing laparoscopic cholecystectomy + common bile duct exploration and lithotomy+modified through-suture T-tube drainage were set as modified group. Observation indicators: (1) intraoperative and postoperative conditions; (2) follow-up. Measurement data with normal distribution were expressed as Mean± SD, and comparison between groups was conducted using the t test. Count data were described as absolute numbers, and comparison between groups was conducted using Fisher exact probability. Results:(1) Intraoperative and postoperative conditions. Both groups of patients successfully completed the operation, with postoperative vital signs as stable, and no discomfort symptoms. There was no significant difference in duration of postoperative hospital stay between the coventional group and the modified group ( P>0.05). (2) Follow-up. Both groups of patients completed 30 days of postoperative outpatient follow-up. There was a significant difference in the sinus wall thickness between the coventional group and the modified group ( P<0.05). Among the 8 patie-nts in the conventional group, T tube was removed in the first 2 cases of patients after T tube angio-graphy 30 days after operation, and biliary fistula occurred in 1 of them and the drainage tube was re-indurated. For the other 6 cases, the time of T tube retention was extended to 6 weeks after surgery. After T tube angiography, the T tube was removed and no biliary fistula occurred. Among the 7 patients in the modified group, 2 cases with residual choledocholithiasis were found by T tube angiography 30 days after operation. After removal of T tube, percutaneous choledochoscopy was performed, in which the sinus wall was well formed and stone removal was smooth. The other 5 pati-ents were confirmed no residual calculi by T-tube angiography, and then the T-tube was removed, with no biliary fistula. Conclusion:Modified through-suture T-tube can be used in laparoscopic biliary tract surgery.

Objective : Angiotensin Ⅱ Type 2 receptor (AT2R) is a major receptor of angiotensin Ⅱ , which has a protective effect on damage to various tissues and organs．In this study，an overexpression plasmid of AT2R was con- structed to explore the effect of overexpression of AT2R on lipopolysaccharide ( LPS ) -induced inflammatory re- sponse in mouse hepatocytes (AML12 cells) ． Methods : Mice tissues and organs were used as samples to amplify the gene of interest (AT2R) fragments containing EcoR Ⅰ and Hind Ⅲ restriction sites，and then the final product was obtained by digestion and ligation．The final positive clones were sequenced and identified．The pCMV-Flag-N- AT2R plasmid was transfected into HEK 293T cells，and the expression of Flag protein was detected by the Western blot method after 24 h．AT2R expression on AML12 cells was observed by Western blot and laser confocal microsco- py．AML12 cells were treated differently and divided into control group，LPS treatment group，pCMV-Flag-N-AT2R group and pCMV-Flag-N-AT2R + LPS group，and cell viability was detected by CCK8．Western blot detected PCNA proteins and observed cell proliferation ; Cytoinflammatory factor levels were detected by qPCR ; Western blot detec- ted the expression level of nuclear transcription factor NF-кB (p65) in cells. Results : The identification and se- quencing results of EcoR I and Hind III double restriction showed that pCMV-Flag-N-AT2R plasmid was successful- ly constructed，and the detection results of the Western blot method showed successful expression of AT2R protein. Laser confocal observed that there were AT2R receptors on AML12 cells，and AT2R recombinant plasmids could be expressed on AML12; Compared with the control group，the viability and proliferation ability of LPS-treated AML12 cells were weakened，while the levels of IL-6 and TNF-α increased，and the expression level of nuclear transcription factor NF-кB (p65) increased．Compared with the LPS group，the viability and proliferation of cells in AML12 cells treated with pCMV-Flag-N-AT2R and LPS were enhanced，while the levels of IL-6 and TNF-α decreased．The ex- pression of the nuclear transcription factor NF-кB ( p65 ) decreased． Conclusion AT2R overexpression plasmids were successfully constructed and successfully expressed on AML12 cells，and AT2R could inhibit the inflammatory response of LPS-induced AML12 cells.

Objective:To investigate the method and effect of retroauricular three flaps for repair of congenital earlobe defect.Methods:From March 2019 to December 2021, the data of patients with congenital earlobe defect treated with retroauricular three-flap method in Beijing Anzhen Hospital, Capital Medical University and Plastic Surgery Hospital, Chinese Academy of Medical Sciences were retrospectively analyzed. The specific method was to design three flaps in the posterior auricular region, A, B, C respectively. The area of flap A was larger 10%-20% than the defect area, and the flap A was rotated in the direction of the anterior and inferior earlobe. The flap B was designed as a rotation flap to repair the secondary defect after flap transplantation. The flap C was designed as a sliding flap to reduce the tension of the wound in the retroauricular region. Postoperative observation included flap blood flow, complications of infection, hematoma, and so on, and scar after wound healing. A questionnaire was used to investigate the satisfaction of patients or guardians, with scores from 1 to 4 indicating dissatisfaction, general satisfaction, satisfaction, and very satisfaction respectively.Results:A total of 10 patients were included, including 3 males and 7 females. Aged from 7-18 years old, with an average of 11 years old. All cases were unilateral lobe defects. Postoperative infection occurred in 1 case and small local hematoma in 1 case. All cases were cured after dressing change without flap necrosis and other complications. After 3 to 6 months of follow-up, there was no flap necrosis, the color, shape and plumpness of the repaired earlobe were good, and the scar behind the ear was concealed. The satisfaction survey showed that 8 cases had great satisfaction and 2 cases had satisfaction.Conclusion:Partial or total defects of earlobe can be repaired by retroauricular three flaps. The reconstructed earlobe has natural shape, hidden scar and satisfactory clinical effect.