ObjectiveTo investigate the effects of 7-dehydrocholesterol reductase （DHCR7） in promoting proliferation， migration， and invasion of lung adenocarcinoma cells and the underlying signaling mechanisms. MethodsThe expression level of DHCR7 in lung adenocarcinoma and its prognosis were analyzed by using public databases. DHCR7 protein expression levels in the lung adenocarcinoma cell lines H1299 and A549 were assessed by Western blot， using the normal lung epithelial cell line BEAS-2B as a control. Small interfering RNA （siRNA） was used to knock down DHCR7 expression in H1299 and A549 cells. Assays including colony formation， CCK-8， wound healing， and Transwell experiments were conducted to assess the proliferation， migration， and invasion of the knockdown cells. Next， Western blot was employed to assess the phosphorylation levels of key signaling molecules in the phosphoinositide 3-kinase/protein kinase B （PI3K/AKT）， janus kinase/signal transducer and activator of transcription 3 （JAK/STAT3），mitogen-activated protein kinase/extracellular signal-regulated kinase pathway （MAPK/ERK） （p-AKT， p-STAT3， p-ERK）. ResultsBioinformatics results indicated that both DHCR7 mRNA and protein were highly expressed in lung adenocarcinoma compared with normal tissues adjacent to cancer. Furthermore， higher DHCR7 mRNA level was associated with poor prognosis （P<0.001）. The expression levels of DHCR7 were significantly higher in both H1299 and A549 cells than that in BEAS-2B cells （P<0.05， P<0.01）. Compared with si-control， the proliferation， migration， and invasion abilities of si-DHCR7 H1299 and A549 cells significantly decreased. Among the phosphorylated signaling molecules detected， p-ERK was significantly downregulated （P<0.000 1， P<0.01） whereas p-AKT and p-STAT3 levels were not significantly changed. ConclusionDHCR7 has prominent effects in promoting the proliferation， migration， and invasion of lung adenocarcinoma cells， and the underlying mechanisms are related to the MAPK/ERK signaling pathway.

ObjectiveTo investigate the biological reparative effects of platelet-rich fibrin （PRF） extract on injured endometrial stromal cells （ESCs） induced by mifepristone and the underlying molecular mechanisms. MethodsAn ESCs injury model was established using mifepristone treatment. Cells were divided into four groups： untreated control （Con）， mifepristone-injured group （M）， mifepristone treatment+PRF extract group （M+P）， and mifepristone treatment+PRF extract+growth factor inhibitors treatment group， including M+P+T， M+P+Me， and M+P+CJ. Cell viability was detected using the CCK-8 assay， and migration ability was evaluated via the scratch wound healing assay. The release kinetics of growth factors， including vascular endothelial growth factor （VEGF）， platelet-derived growth factor-BB （PDGF-BB）， and transforming growth factor-beta 1 （TGF-β1） from PRF extract were measured by ELISA. The mRNA and protein expression levels of apoptosis-related factors （Bcl-2， Bax， and Caspase-3） were analyzed by RT-qPCR and Western blot， respectively. ResultsVEGF， PDGF-BB， and TGF-β1 were continuously released from the PRF extract over two weeks， with peak release observed on days 3-7. The extract significantly restored the proliferation and migration of mifepristone-injured ESCs （all P<0.000 1）. PRF extract up-regulated the mRNA and protein expression of the anti-apoptotic factor Bcl-2 （all P<0.000 1） and down-regulated that of the pro-apoptotic factors Bax and Caspase-3 （all P<0.000 1） in mifepristone-injured ESCs. Inhibitors of VEGF， PDGF-BB， and TGF-β1 （Tanshinone IIA， Methylnissolin， and CJJ300） significantly reversed the protective effects of PRF extract on mifepristone-injured ESCs （all P<0.05）. ConclusionPRF extract promotes the repair of injured ESCs by enhancing cell proliferation， attenuating apoptosis， and increasing migration capacity， which involve multiple growth factors， including VEGF， PDGF-BB， and TGF-β1.

Objective To understand the epidemiological characteristics and trends of postoperative pneumonia(POP)in tertiary general hospitals in Jiangsu Province,and provide theoretical basis for carrying out targeted pre-vention and control measures.Methods Surgery patients from 22 tertiary general hospitals in 12 cities in north,central,and south of Jiangsu Province from January 1,2022 to December 31,2023 were chosen as studied subjects,occurrence of POP was analyzed and compared.Results A total of 848 274 surgical procedures were performed in 22 hospitals,and 3 606 cases of POP occurred,with an incidence of 0.43％.The incidence in 2023 was 0.37％,which was lower than that in 2022(0.49％),with statistically significant difference(P＜0.001).The top three de-partments with high incidence of POP were neurosurgery(6.71％),cardiothoracic surgery(2.91％),and general surgery(0.77％).Among hospitals of different grades,the incidence of POP in tertiary first-class hospitals was 0.44％,which was higher than that in other tertiary hospitals(0.37％).There was no statistically significant difference in the incidence of POP between municipal and district/county hospitals(P＞0.05).The incidence of POP in hospitals with a bed:infection control full-time staff ratio＜200∶1 was lower than that in hospitals with the ratio ≥200∶1(0.39％vs 0.47％,P＜0.001),while the incidence of POP in hospitals with a proportion ≥30％of full-time staff being doctors was higher than that in hospitals with a proportion＜30％(0.45％vs 0.36％,P＜0.001).The incidence of POP in male patients was higher than that in female patients(0.62％vs 0.26％,P＜0.001).The incidence of POP in elderly patients aged≥65 was higher than that in patients aged＜65(0.73％vs 0.26％,P＜0.001).A total of 2 667 strains of infectious pathogens were detected,with the top three being Acine-tobacter baumannii,Klebsiella pneumoniae,and Pseudomonas aeruginosa,accounting for 28.95％,22.72％,and 15.45％,respectively.The detection rates of carbapenem-resistant Acinetobacter baumannii(CRAB),carba-penem-resistant Klebsiella pneumoniae(CRKP),and carbapenem-resistant Pseudomonas aeruginosa(CRPA)were 60.75％,21.45％,and 32.28％,respectively.The detection rate of CRKP decreased in 2023 compared with 2022,with statistically significant difference(P＜0.05).Conclusion The overall incidence of POP in tertiary general hos-pitals in Jiangsu Province is relatively low,but there are significant differences among different hospitals.There-fore,perioperative prevention and control measures should be carried out based on the epidemiological characteristics of patients.

Objective:To explore the mediating effect of psychological resilience between perceived stress and job burnout among standardized gastroenterology nursing training students.Methods:A total of 156 nursing trainees who received standardized training in the Department of Gastroenterology at Shaanxi Provincial People's Hospital between December 2022 and July 2024 were selected by the convenience sampling method. Data were collected using a general information questionnaire, the Connor-Davidson Resilience Scale, the Chinese Perceived Stress Scale, and the Maslach Burnout Inventory-General Survey. A Pearson correlation analysis was used to examine the relationship among perceived stress, psychological resilience, and job burnout in standardized gastroenterology nursing training students. AMOS 24.0 statistical software was used to construct a structural equation model to analyze the mediating effect of psychological resilience between perceived stress and job burnout in standardized gastroenterology nursing training students. The bias-corrected bootstrap method was applied to test the mediating effect of psychological resilience.Results:The averaged total scores of 156 standardized gastroenterology nursing training students were (29.89±0.30) for perceived pressure, (62.45±2.44) for psychological resilience, and (57.85±3.44) for job burnout. Of the trainees, 88 (56.41%) exhibited job burnout, including 39 (25.00%) with mild burnout, 41 (26.28%) with moderate burnout, and 8 (5.13%) with severe burnout. The Pearson correlation analysis showed that perceived stress was positively correlated with job burnout ( r=0.543, P<0.05) and negatively correlated with psychological resilience ( r=-0.443, P<0.05), and psychological resilience was negatively correlated with job burnout ( r=-0.478, P<0.05). The results of bias-corrected bootstrap test showed that psychological resilience had a partial mediating effect between perceived stress and job burnout among standardized gastroenterology nursing training students ( P<0.05), accounting for 32.63% of the total effect. Conclusions:Moderate job burnout was observed in standardized gastroenterology nursing training students. Job burnout was closely related to perceived stress and psychological resilience. Psychological resilience partly mediated the relationship between perceived stress and job burnout. Therefore, clinical managers may alleviate the perceived psychological pressure and subsequently reduce the occurrence of job burnout among standardized nursing training students by increasing psychological resilience.

The 2024 National Education Work Conference pointed out that at the current juncture of the critical period for achieving the goals and tasks of the 14th Five-Year Plan,the implementation of the Education Powerhouse Construction Plan Outline should be taken as the main line of work,and building first-class disciplines is an crucial task for a higher education powerhouse.In 2022,forensic medicine was officially listed as a first-level discipline under the medical category,presenting an un-precedented historical opportunity for the development of forensic medicine.The forensic medicine dis-cipline of Southern Medical University comprehensively improves the quality of talent cultivation and facilitates the construction of first-class disciplines as its main direction.It aims to initiate and imple-ment a high-level faculty team building plan featuring"combining recruitment and cultivation,inter-disciplinary integration";make vigorous efforts to establish a first-level doctoral program,refine advan-tageous second-level disciplines and research directions;and establish an innovative research platform from a high starting point with deep integration.The discipline adheres to moral cultivation and the Five Domains of Education simultaneous development,to build a high-quality talent joint training model.Guided by the construction of the national legal system and industry needs,the discipline will enhance social service capabilities.The forensic medicine construction in our university will continue to contribute to the rule of law in China and educational power.

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 explore the mediating effect of psychological resilience between perceived stress and job burnout among standardized gastroenterology nursing training students.Methods:A total of 156 nursing trainees who received standardized training in the Department of Gastroenterology at Shaanxi Provincial People's Hospital between December 2022 and July 2024 were selected by the convenience sampling method. Data were collected using a general information questionnaire, the Connor-Davidson Resilience Scale, the Chinese Perceived Stress Scale, and the Maslach Burnout Inventory-General Survey. A Pearson correlation analysis was used to examine the relationship among perceived stress, psychological resilience, and job burnout in standardized gastroenterology nursing training students. AMOS 24.0 statistical software was used to construct a structural equation model to analyze the mediating effect of psychological resilience between perceived stress and job burnout in standardized gastroenterology nursing training students. The bias-corrected bootstrap method was applied to test the mediating effect of psychological resilience.Results:The averaged total scores of 156 standardized gastroenterology nursing training students were (29.89±0.30) for perceived pressure, (62.45±2.44) for psychological resilience, and (57.85±3.44) for job burnout. Of the trainees, 88 (56.41%) exhibited job burnout, including 39 (25.00%) with mild burnout, 41 (26.28%) with moderate burnout, and 8 (5.13%) with severe burnout. The Pearson correlation analysis showed that perceived stress was positively correlated with job burnout ( r=0.543, P<0.05) and negatively correlated with psychological resilience ( r=-0.443, P<0.05), and psychological resilience was negatively correlated with job burnout ( r=-0.478, P<0.05). The results of bias-corrected bootstrap test showed that psychological resilience had a partial mediating effect between perceived stress and job burnout among standardized gastroenterology nursing training students ( P<0.05), accounting for 32.63% of the total effect. Conclusions:Moderate job burnout was observed in standardized gastroenterology nursing training students. Job burnout was closely related to perceived stress and psychological resilience. Psychological resilience partly mediated the relationship between perceived stress and job burnout. Therefore, clinical managers may alleviate the perceived psychological pressure and subsequently reduce the occurrence of job burnout among standardized nursing training students by increasing psychological resilience.

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 understand the epidemiological characteristics and trends of postoperative pneumonia(POP)in tertiary general hospitals in Jiangsu Province,and provide theoretical basis for carrying out targeted pre-vention and control measures.Methods Surgery patients from 22 tertiary general hospitals in 12 cities in north,central,and south of Jiangsu Province from January 1,2022 to December 31,2023 were chosen as studied subjects,occurrence of POP was analyzed and compared.Results A total of 848 274 surgical procedures were performed in 22 hospitals,and 3 606 cases of POP occurred,with an incidence of 0.43％.The incidence in 2023 was 0.37％,which was lower than that in 2022(0.49％),with statistically significant difference(P＜0.001).The top three de-partments with high incidence of POP were neurosurgery(6.71％),cardiothoracic surgery(2.91％),and general surgery(0.77％).Among hospitals of different grades,the incidence of POP in tertiary first-class hospitals was 0.44％,which was higher than that in other tertiary hospitals(0.37％).There was no statistically significant difference in the incidence of POP between municipal and district/county hospitals(P＞0.05).The incidence of POP in hospitals with a bed:infection control full-time staff ratio＜200∶1 was lower than that in hospitals with the ratio ≥200∶1(0.39％vs 0.47％,P＜0.001),while the incidence of POP in hospitals with a proportion ≥30％of full-time staff being doctors was higher than that in hospitals with a proportion＜30％(0.45％vs 0.36％,P＜0.001).The incidence of POP in male patients was higher than that in female patients(0.62％vs 0.26％,P＜0.001).The incidence of POP in elderly patients aged≥65 was higher than that in patients aged＜65(0.73％vs 0.26％,P＜0.001).A total of 2 667 strains of infectious pathogens were detected,with the top three being Acine-tobacter baumannii,Klebsiella pneumoniae,and Pseudomonas aeruginosa,accounting for 28.95％,22.72％,and 15.45％,respectively.The detection rates of carbapenem-resistant Acinetobacter baumannii(CRAB),carba-penem-resistant Klebsiella pneumoniae(CRKP),and carbapenem-resistant Pseudomonas aeruginosa(CRPA)were 60.75％,21.45％,and 32.28％,respectively.The detection rate of CRKP decreased in 2023 compared with 2022,with statistically significant difference(P＜0.05).Conclusion The overall incidence of POP in tertiary general hos-pitals in Jiangsu Province is relatively low,but there are significant differences among different hospitals.There-fore,perioperative prevention and control measures should be carried out based on the epidemiological characteristics of patients.

AIM To optimize the extraction process for uracil,hypoxanthine,xanthine,uridine,thymine,inosine,guanosine and 2'-deoxyguanosine from Pheretima guillelmi(Michaelsen),and to determine their contents.METHODS With solid-liquid ratio,ultrasonic time and ultrasonic temperature as influencing factors,contents of hypoxanthine and total nucleosides as evaluation indices,the extraction process was optimized by orthogonal test.HPLC was adopted in the content determination of varioud nucleosides,the analysis was performed on a 30℃thermostatic Agilent C18 column(4.6 mm×250 mm,5 μm),with the mobile phase comprising of methanol-water flowing at 1 mL/min in a gradient elution manner,and the detection wavelength was set at 260 nm.RESULTS The optimal conditions were determined to be 1∶250 for solid-liquid ratio,60 min for ultrasonic time,and 60℃for ultrasonic temperature.Eight nucleosides showed good linear relationships within their own ranges(R2＞0.999 0),whose average recoveries were 99.11%-103.27%with the RSDs of 0.85%-2.89%.CONCLUSION This stable and reliable method can be used for the extraction and content determination of nucleosides from P.guillelmi.