Objective To establish and evaluate a rapid detection method for SARS-CoV-2 based on reverse transcriptase-recombinase aided amplification(RT-RAA)combined with the clustered regularly interspaced short palindromic repeats(CRISPR)/Cas12a system.Methods RT-RAA primers and CRISPR-derived RNA(crRNA)were designed based on the nucleocapsid(N)gene of SARS-CoV-2 from NCBI database.The detection system was optimized with magnesium acetate(MgAc)concentration,RT-RAA reaction tempera-ture and time and LbCas12a reaction temperature.The sensitivity and specificity of the method were evaluated using recombinant plas-mids(100-106 copies/μL)and other respiratory pathogens.The RT-RAA-CRISPR/Cas12a method was compared with RT-PCR by tes-ting 70 clinical samples in parallel.Results The optimized RT-RAA-CRISPR/Cas12a assay could detect SARS-CoV-2 within 50 min at 37 ℃.The limit of detection was 10 copies/μL for the fluorescence-based method and 1×102 copies/μL for the lateral flow assay.The method specifically detected SARS-CoV-2 without cross-reactivity to other respiratory pathogens.The results of testing 70 clinical samples using RT-RAA-CRISPR/Cas12a showed agreement of 100％with those of RT-PCR.Conclusion The established RT-RAA-CRISPR/Cas12a assay for SARS-CoV-2 detection is rapid,cost-effective,highly sensitive and specific.It can be performed by less experienced personnel and no expensive equipment is required,thus it may provide a new approach for rapid clinical diagnosis and large-scale on-site screening of SARS-CoV-2.

Background::Carotid intima-media thickness (IMT) and diameter, stiffness, and wave reflections, are independent and important clinical biomarkers and risk predictors for cardiovascular diseases. The purpose of the present study was to establish nationwide reference values of carotid properties for healthy Chinese adults and to explore potential clinical determinants.Methods::A total of 3053 healthy Han Chinese adults (1922 women) aged 18-79 years were enrolled at 28 collaborating tertiary centers throughout China between April 2021 and July 2022. The real-time tracking of common carotid artery walls was achieved by the radio frequency (RF) ultrasound system. The IMT, diameter, compliance coefficient, β stiffness, local pulse wave velocity (PWV), local systolic blood pressure, augmented pressure (AP), and augmentation index (AIx) were then automatically measured and reported. Data were stratified by age groups and sex. The relationships between age and carotid property parameters were analyzed by Jonckheere-Terpstra test and simple linear regressions. The major clinical determinants of carotid properties were identified by Pearson’s correlation, multiple linear regression, and analyses of covariance.Results::All the parameters of carotid properties demonstrated significantly age-related trajectories. Women showed thinner IMT, smaller carotid diameter, larger AP, and AIx than men. The β stiffness and PWV were significantly higher in men than women before forties, but the differences reversed after that. The increase rate of carotid IMT (5.5 μm/year in women and 5.8 μm/year in men) and diameter (0.03 mm/year in both men and women) were similar between men and women. For the stiffness and wave reflections, women showed significantly larger age-related variations than men as demonstrated by steeper regression slopes (all P for age by sex interaction <0.05). The blood pressures, body mass index (BMI), and triglyceride levels were identified as major clinical determinants of carotid properties with adjustment of age and sex. Conclusions::The age- and sex-specific reference values of carotid properties measured by RF ultrasound for healthy Chinese adults were established. The blood pressures, BMI, and triglyceride levels should be considered for clinical application of corresponding reference values.

It is difficult to accurately distinguish pharyngitis caused by Group A Streptococcus(GAS) from other pathogens according to the clinical presentation alone, which cannot effectively guide the rational use of antimicrobials.The pharyngeal swab culture, rapid antigen detection test, nucleic acid test, and blood test can help definitively diagnose GAS pharyngitis.However, there are differences in different guidelines on who the laboratory test methods are intended for, interpretation of laboratory test results and so on.This article summarizes and analyses the laboratory diagnostic modalities and their characteristics, as well as recommendations for GAS pharyngitis in different guidelines to provide references for the clinical diagnosis, antimicrobial treatment, and further study of GAS pharyngitis.

Objective:To evaluate the clinical efficacy of modified endoscopic mucosal resection (EMR) in the management of early gastrointestinal lesions.Methods:Upon endoscopic identification of the lesion, normal saline is injected into the submucosa to establish a fluid cushion, which elevates the lesion's mucosa. Methylene blue may also be applied to improve visualization of the relationship between the submucosa and muscular layer. A snare with a tip diameter of 2-3 mm is utilized to circumferentially incise the mucosal layer at the lesion's edge, forming a circular groove. The snare is anchored within this groove, allowing for complete resection of the lesion in a single step. The procedure involves a slow and alternating technique of electrosurgical cutting and coagulation to minimize bleeding risks, while upward tension on the snare during cutting reduces perforation risks. Direct coagulation of exposed blood vessels is performed using the snare tip, and hemostatic clips are applied to larger defects; nylon sutures may be utilized for substantial wounds.Results:Between June 2015 and April 2024, modified EMR was performed on 65 patients with early gastrointestinal lesions at Dongguan Children's Hospital, Guangdong Medical University. The mean operative time was (15.2 ± 3.1) minutes, with a complete resection rate of 100% and negative margins confirmed. Postoperative complications included one case each of delayed bleeding and electrosurgical syndrome. The average cost of consumables was (1887.2±187.6) yuan. Follow-up colonoscopies at 3 and 6 months postoperatively indicated no recurrences.Conclusions:Modified EMR demonstrates a short operative time, high safety and efficacy, and reduced material costs in the treatment of early gastrointestinal mucosal lesions.

Objective:To evaluate the clinical efficacy of modified endoscopic mucosal resection (EMR) in the management of early gastrointestinal lesions.Methods:Upon endoscopic identification of the lesion, normal saline is injected into the submucosa to establish a fluid cushion, which elevates the lesion's mucosa. Methylene blue may also be applied to improve visualization of the relationship between the submucosa and muscular layer. A snare with a tip diameter of 2-3 mm is utilized to circumferentially incise the mucosal layer at the lesion's edge, forming a circular groove. The snare is anchored within this groove, allowing for complete resection of the lesion in a single step. The procedure involves a slow and alternating technique of electrosurgical cutting and coagulation to minimize bleeding risks, while upward tension on the snare during cutting reduces perforation risks. Direct coagulation of exposed blood vessels is performed using the snare tip, and hemostatic clips are applied to larger defects; nylon sutures may be utilized for substantial wounds.Results:Between June 2015 and April 2024, modified EMR was performed on 65 patients with early gastrointestinal lesions at Dongguan Children's Hospital, Guangdong Medical University. The mean operative time was (15.2 ± 3.1) minutes, with a complete resection rate of 100% and negative margins confirmed. Postoperative complications included one case each of delayed bleeding and electrosurgical syndrome. The average cost of consumables was (1887.2±187.6) yuan. Follow-up colonoscopies at 3 and 6 months postoperatively indicated no recurrences.Conclusions:Modified EMR demonstrates a short operative time, high safety and efficacy, and reduced material costs in the treatment of early gastrointestinal mucosal lesions.

This study explores the application effect of the case-based teaching method based on Xuexitong learning platform in the online teaching of Digestive System, and analyzes the learner's emotional experience, learning behavior, and learning effect in the case-based online teaching. The results of the study show that the case-based online teaching model based on Xuexitong learning platform improves students' online learning interest, and the students have good emotional experience, high learning enthusiasm, good classroom interaction, enhanced self-learning ability before and after class, and good learning effect. In addition, precise teaching can be used for individual students who are not enthusiastic about online learning.

Objective: To investigate the relation of Epstein-Barr virus (EBV)-induced immune escape to regulatory T cells(Treg) in nasopharyngeal carcinoma(NPC). Methods: We recruited 83 patients who were pathologically diagnozed as nasopharyngeal carcinoma and treated in Nanfang Hospital from January to September 2016. CD4⁺ CD25⁺ FOXP3⁺ Treg in peripheral blood was examined by flow cytometry and the level of EBV DNA in the blood was detected by quantitative real-time polymerase chain reaction(qRT-PCR)in 83 patients and 51 healthy adults as control. The expression of FOXP3⁺ Treg and EBER in NPC in 32 of 83 patients and in nasopharyngitis in 16 control patients were tested by immunohistochemistry(IHC) and in-situ hybridization(ISH). Results: The ratio of Treg in blood in patients with NPC(5.29±1.45)% was higher than that in control group (4.78±1.19) %, with a statistically significant difference(P=0.035). The ratio of Treg in blood in patients with positive EBV was higher than that in patients with negative EBV(P=0.013), and there was a positive correlation between EBV DNA copies and Treg ratio(r=0.335, P=0.002). The density of FOXP3⁺ Treg in NPC was higher than that in nasopharyngitis(P=0.001). Positive correlation was found between the density of FOXP3⁺ Treg and the stain intensity of EBER(r=0.496, P=0.004). Conclusion The ratios of Treg in blood and tissue in NPC patients with positive EBV are significantly increased, indicating a role of Treg in EBV-induced immune escape in NPC.

Objective To com pare and explore the application value of diatom nitric acid digestion method and plankton 16S rDNA PCR method for drow ning identification. Methods Forty drow ning cases from 2010 to 2011 were collected from Department of Forensic Medicine of Wenzhou Medical University. Sam ples including lung, kidney, liver and field water fromeach case were tested with diatom nitric acid digestion method and plankton 16S rDNAPCR method, respectively. The Diatom nitric acid digestion method and plankton 16S rDNAPCR method required 20 gand 2g of each organ,and 15 mL and 1.5 mL of field water, respectively. The inspection time and detection rate were com pared between the two methods. Results Diatom nitric acid digestion method m ainly detected two species of diatom s, Centriae and Pennatae, while plankton 16S rDNA PCR method am plified a length of 162 bp band. The average inspection time of each case of the Diatom nitric acid digestion method was (95.30±2.78) min less than (325.33±14.18)min of plankton 16S rDNA PCR method (P<0.05).The detection rates of two methods for field water and lung were both 100% . For liver and kidney, the detection rate of plankton 16S rDNA PCR method was both 80% , higher than 40% and 30% of diatom nitric acid digestion method (P<0.05), respectively. Conclusion The laboratory testing method needs to be appropriately selected according to the specific circum stances in the forensic appraisal of drow ning. Com pared with diatom nitric acid digestion method, plankton 16S rDNA PCR method has practice values with such advantages as less quantity of sam ples, huge inform ation and high specificity.

Basic knowledge of forensic science is theoretical and abstract,therefore,confir-matory experiment teaching is often adopted in the experiment teaching. International education has become an important topic in medical colleges and universities. Forensic medicine is a compulsory subject for medical international students. This article discussed the exploration and practice in teach-ing forensic medicine for international students at Wenzhou Medical University,which included faculty constructing and training,encouraging whole English teaching by young teachers,applying heuristic interactive teaching and case teaching,establishing strict attendance and appraisal system and con-ducting comprehensive evaluation on medical teaching quality and teaching management.

Objective To investigate the clinical features of aortic dissection (AD) and emergency treatments. Methods Data from 784 patients with aortic dissection were collected in the Department of Emergency from January 2000 through December 2009. A retrospective analysis was carried out to determine the survival rate, mortality rate and treatment efficiency. Results Pain was the most common onset symptom (77.7% , 609/784). The majority of patients (86.5%) had essential hypertension (678/784). All the patients with preoperative diagnosis of aortic dissection underwent emergency medical intervention by internists resulting in 81.5% survival rate (639/784) and 18.5% mortality rate (145/784). There were 157 patients without improvement (20.0% ) and the total efficiency rate was (83. 1% ). The efficiency rate of conventional treatment was 76.4% , while the efficiency rate of triple four-procedure treatment was 89. 8% (P<0.05). Of them, 139 patients (17. 7% ) died in the hospital. Among them,. 26 patients died within 24 hours (18.4% ) and 47 cases died within 48 hours (33. 8% ) and 66 patients died within 72 hours (47.2% ). There were 92 patients who refused treatments after diagnosis, and among them, 81 patients died within 72 hours (88.04% ). The difference in mortality rate between two groups was significant (P<0.05). Conclusions The diagnosis of aortic dissection depends on detailed history, physical examination and CT or MRI imaging. Analgesia, sedation and control of blood pressure are essential for emergency treatments. Early diagnosis and effective emergency treatments are the critical strategy for the early surgical intervention and time window for further treatment to improve the survival rate of AD.