Objective:Based on the specific cleavage and non-specific "trans-cleavage" activities of the clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated protein(CRISPR/Cas13), we established a visually amplification-free rapid detection technique of 2019-nCoV nucleic acid. This technique is easily processed with a low detection limit and good specificity.Methods:According to the 2019-nCoV gene sequence, specific CRISPR RNAs were screened and designed by bioinformatics analysis, and then synthesized as universal signal-strained RNA transcription targets in vitro to establish and optimize the reaction system. Moreover, the 2019-nCoV pseudoviral nucleic acid was used as a standard substance to evaluate the detection limit. A total of 65 positive samples were collected from various 2019-nCoV variants, while 48 negative samples included other clinically common respiratory pathogens, such as influenza A virus, influenza B virus, human parainfluenza virus, Klebsiella pneumonia, etc. All samples were tested by quantitative PCR (qPCR), digital PCR, and the method established in this study. The sensitivity and specificity of the newly established method were analyzed and evaluated. Results:With the newly established technique, the detection time for 2019-nCoV nucleic acid could be minimized to 6 minutes. In addition, the detection limit was 14 copies/μl when assisted by the displaying instrument, whereas it increased to 28 copies/μl with the naked eye. This technique had a sensitivity and specificity of 98.5% (66/67) and 100% (46/46) respectively, showing no statistically significant difference compared to the gold standard qPCR( P=1). Conclusions:This study has successfully established a CRISPR/Cas13a-based visually rapid detection technique for 2019-nCoV nucleic acid. This technique offers the advantages of a simple process, convenient operation, low environmental operating requirements, a detection limit close to qPCR, and a strong potential for on-site testing applications.

Traditional Chinese medicine monomer has certain curative effects in tumor treatment,but its low targeting and difficulty in gathering at the tumor site limit its application.As a new type of drug delivery method,environmentally responsive nano drug delivery system has the advantages of targeted drug delivery,reducing drug side effects,and environmentally responsive release,and has been widely used in tumor treatment.In this paper,by consulting and sorting out the relevant literature,the general situation of traditional Chinese medicine monomers in the treatment of tumors,the classification of environment-responsive traditional Chinese medicine monomer nano drug delivery system,and its application in tumor treatment are summarized in three aspects,to provide ideas for solving the limitations of traditional Chinese medicine monomer in the treatment of tumor.

OBJECTIVE To investigate the activation of xanthine oxidase(XO)from the human liver by vitamin K3 and the mechanism.METHODS Using human liver S9(0.1 g·L-1)as the source,XO was incubated with substrate xanthine of 0,2,4,8,and 16 μmol·L-1 at 37℃ for 90 min.The Michaelis constant(Km)of the reaction of xanthine oxidation was determined using the liquid chromatography diode array method.At the concentration of Km,the three-point method(1,10 and 100 μmol·L-1)was used to detect the activity of vitamin K3 activators.The multi-point method(vitamin K3 1,2,5,10,20,50,100,200 and 400 μmol·L-1)was adopted to determine the half effective concentration(EC50)of activated XO.Kinetic parameters(Km and Vmax)and the fit of double reciprocal curves were determined via vitamin K3 of 1/2EC50,EC50 and 2EC50.The changes in kinetic behavior at different concentrations of vitamin K3 were observed and their types of activation were analyzed.The interactions between XO and activator vitamin K3 were explored via molecular docking.RESULTS The Km of XO-mediated xanthine oxidation reac-tion was 4.71 μmol·L-1.As an activator of this reaction,vitamin K3 activated XO in a concentration-dependent manner(according to the logistic fitting formula y=A2+(A1-A2)/(1+(x/x0)^p),with an EC50 of 32.0 μmol·L-1.The kinetic parameters also changed after the addition of vitamin K3.The Km value decreased(4.71-1.34 μmol·L-1)with the increase of vitamin K3 concentrations,while the Vmax value increased(0.08-1.31 μmol·min-1·g-1),leading to an increase in Vmax/Km(17.0-977.6 mL·min·g-1).In addition,the double reciprocal curve fitting found that the activation type of vitamin K3 on XO was mixed.The molecular docking results showed that vitamin K3 bound to the molybdopterin domain of XO and maintained hydrogen bonding interactions with Arg599 and Ser605.CONCLUSION Vitamin K3 is an activator of XO,which can form hydrogen bonds with Arg599 and Ser605 in the XO domain,regu-late its affinity with the substrate xanthine,activate XO and increase the uric acid level.

Objective To investigate the inhibitory effects of pyruvate-ferredoxin oxidoreductase(PFOR)by luteolin and its anti-Clostridium difficile effect.Methods The PFOR encoding sequence of Clostridium difficile was cloned into the expression vector pET-2a and transformed into competent Escherichia coli.The crude enzyme was prepared after induction with IPTG(Isopropyl β-D-Thiogalactoside).The inhibitory rate of the test compounds on PFOR was determined after an 8-hour anaerobic reaction between PFOR and 40 μmol·L-1 of test compounds at 25℃.The minimum inhibitory concentration(MIC)of PFOR inhibitors against C.difficile strains(ATCC BAA 1382 and ATCC BAA 1870)was determined by monitoring the OD600 of the bacterial culture.Molecular docking was performed to investigate the possible interaction mechanisms between PFOR and inhibitors.Results Among the tested compounds,the luteolin showed the strongest inhibitory activity against PFOR,with a single-point inhibition rate of approximately 33%,which is comparable to that observed with the positive inhibitor nitazoxanide(40%).Molecular docking revealed that luteolin could form hydrogen bonds with Asp428,Val431,Gly429,Asp456,Lys458,Lys459,and other residues in the PFOR domain.The MIC of luteolin against C.difficile was approximately 32 μg·mL-1.Conclusion Luteolin exhibits good activity against C.difficile,and PFOR may be a target for its antibacterial action.

ObjectiveTo observe the effect of Zuoguiwan on ovarian reserve in the female offspring rat model of prenatal stress （PS） and explore the mechanism based on Toll-like receptor 4/nuclear factor-κB p65 （TLR4/NF-κB p65） signaling pathway. MethodThirty-two pregnant rats were prepared and randomized into four groups （n=8）： control， model， Zuoguiwan （18.9 mg·kg^-1）， and vitamin E （1.44 mg·kg^-1）. Except the control group， the other three groups were subjected to chronic unpredictable mild stress （CUMS） from day 11 of pregnancy， and the modeling was accompanied by gavage with corresponding drugs until delivery. The PS model was evaluated by the sucrose preference test， open field test， and serum corticosterone （CORT） level. The estrous cycle was monitored and the morphological changes in the ovarian tissue were observed. The serum levels of estradiol （E₂）， luteinizing hormone （LH）， follicle-stimulating hormone （FSH）， and anti-Mullerian hormone （AMH） in the 75-day-old offspring rats were measured by enzyme-linked immunosorbent assay （ELISA） to evaluate the ovarian reserve. The ovary and uterus indices were calculated. The serum levels of interleukin-1β （IL-1β） and tumor necrosis factor-α （TNF-α） were measured by enzyme-linked immunosorbent assay （ELISA）. The morphology of the ovarian tissue in the offspring on the day of birth and day 75 after birth was observed by hematoxylin-eosin staining. The transport of NF-κB p65 to the nucleus in the ovaries of the 75-day-old offspring was detected by the immunofluorescence （IF） assay. The expression of TLR4， NF-κB p65 and other related proteins in the ovarian tissue was determined by Western blot. ResultCompared with the control group， the model group showed reduced primordial follicles in the offspring on the day of birth （P<0.01） as well as disturbed estrous cycle， decreased ovary index and uterus index （P<0.01）， reduced corpus luteum， increased atretic follicles （P<0.01）， lowered serum levels of AMH and E₂ （P<0.01）， elevated serum levels of LH， FSH， IL-1β， and TNF-α （P<0.05， P<0.01）， and up-regulated protein levels of TLR4， NF-κB p65， recombinant myeloid differentiation factor 88 （MyD88）， and phosphorylated NF-κB inhibitor （p-IκBα） （P<0.01） in the 75-day-old offspring rats. Compared with the model group， Zuoguiwan and vitamin E increased the primordial follicles in the offspring on the day of birth （P<0.01）. Moreover， they resumed the estrous cycle， increased the ovary and uterine indices （P<0.05， P<0.01） and corpus luteum （P<0.01）， reduced atretic follicles （P<0.01）， elevated the serum levels of AMH and E₂ （P<0.05， P<0.01）， lowered the serum levels of LH， FSH， IL-1β， and TNF-α （P<0.05， P<0.01）， and down-regulated the expression of TLR4， NF-κB p65， MyD88， and p-IκB-α （P<0.05， P<0.01） in the 75-day-old offspring. ConclusionZuoguiwan can improve the ovarian reserve in the offspring rat model of congenital kidney deficiency by regulating the TLR4/NF-κB p65 signaling pathway.

Epidemiology and medical statistics are essential courses for undergraduate students majoring in clinical medicine. By studying the two courses, they can obtain the core skills for their future clinical practice. High-level medical schools both at home and abroad have accumulated successful experiences in curriculum, teaching methods and teaching models of the two disciplines. These colleges have also carried out the exploration of the curriculum reform centering on "organ systems integration". This paper summarizes the current status of epidemiology and medical statistics teaching and curriculum integration in representative medical schools both at home and abroad, and puts forward suggestions for deepening teaching reform and optimizing the curriculum system to provide reference for the integration of epidemiology and medical statistics curriculums for undergraduate students majoring in clinical medicine in China.

Objective:To discuss the protective effect of polygonatum odoratum polysaccharide(POP)on the mice with cisplatin-induced acute kidney injury(AKI),and to clarify its possible mechanism.Methods:Forty male C57BL/6 mice were randomly divided into control group,model group,POP group,and ferroptosis inducer Erastin combined with POP(Erastin+POP)group,and there were 10 mice in each group.The mice in POP group and Erastin+POP group were given intragastric administration of POP(400 mg·kg-1),and on the 7th day,the mice in model group,POP group,and Erastin+POP group were intraperitoneally injected with cisplatin(20 mg·kg-1)to establish the AKI models,the mice in control group were injected with the same volume of normal saline,and the mice in Erastin+POP group were intraperitoneally injected with Erastin(40 mg·kg-1)one day in advance(on the 6th day of the experiment).After 9 d,the mice were killed and the serum and kidney tissue were collected,and the levels of serum creatinine(Scr)and blood urea nitrogen(BUN)and the levels of malondialdehyde(MDA)and glutathione(GSH)in kidney tissue of the mice in various groups were detected by kit;HE staining was used to observe the pathomorphology of kidney tissue of the mice in various groups;the expression levels of ferroptosis suppressor protein 1(FSP1),ferritin heavy chain 1(FTH1),and glutathione peroxidase 4(GPX4)proteins in kidney tissue of the mice in various groups were detected by immunohistochemistry;Western blotting method was used to detect the expression levels of nuclear factor-E2-related factor 2(Nrf2)and heme oxygenase-1(HO-1)proteins in kidney tissue of the mice in various groups.Results:Compared with control group,the levels of Scr and BUN of the mice in model group were significantly increased(P＜0.01),the level of MDA in kidney tissue was significantly increased(P＜0.01),and the level of GSH was significantly decreased(P＜0.01);most kidney tubules were dilated,the epithelial cells were swollen,the vacuolar degeneration and epithelial cells fell off,and the protein-like tubules could be seen in the lumen;the expression levels of FSP1,FTH1,GPX4,Nrf2,and HO-1 proteins in kidney tissue were decreased significantly(P＜0.05 or P＜0.01).Compared with model group,the levels of Scr and BUN of the mice in POP group were significantly decreased(P＜0.01),the level of MDA in kidney tissue was significantly decreased(P＜0.01),and the level of GSH was significantly increased(P＜0.01);the dilatation of kidney tubular lumen,epithelial cell swelling,vacuolar degeneration,and epithelial cell exfoliation were decreased;the expression levels of FSP1,FTH1,GPX4,Nrf2,and HO-1 proteins in kidney tissue of the mice in POP group were significantly increased(P＜0.05 or P＜0.01).Compared with POP group,the levels of Scr and BUN of the mice in Erastin+POP group were significantly increased(P＜0.01),the level of MDA in kidney tissue was increased(P＜0.05),and the level of GSH was significantly decreased(P＜0.01);the pathological injury of kidney tissue was aggravated obviously;the expression levels of FSP1,FTH1,GPX4,Nrf2,and HO-1 proteins in kidney tissue were significantly decreased(P＜0.05 or P＜0.01).Conclusion:POP can reduce the AKI in the mice induced by cisplatin,and its mechanism may be related to the inhibitory effect of POP on the ferroptosis induced by cisplatin.

With a deepened understanding of the pathophysiology and pathogenesis of thoracic malignancies, the treatment has been transited from traditional treatment on the basis of surgery, radiotherapy, and chemotherapy to individualized and precise targeted therapy and immunotherapy. As an antitumor immunotherapy, chimeric antigen receptor gene-modified T (CAR-T) cells have been approved by the FDA for the treatment of hematological malignancies in five CAR-T products. They have also achieved good therapeutic effects in solid tumors. However, significant challenges remain in the clinical application of CAR-T cell immunotherapy in thoracic malignancies. In this review, the latest research progress of CAR-T cell immunotherapy in the treatment of thoracic malignancies were summarized, including the basic characteristics of CAR-T cells, the popular target antigens, and the existing problems and challenges, to provide new ideas and strategies for clinical immunotherapy of thoracic malignancies.

Objective:To understand the infection status and characteristics of 2019-nCoV infection in different areas in China after the adjustment of the national prevention and control strategy of 2019-nCoV infection.Methods:The online questionnaire survey was conducted among staff and students of 39 public health schools in 23 provinces (municipalities) in China from 12: 00 on December 20 to 9: 00 on December 23, 2022. The infection rates in staff and students in all the provinces were estimated. The risk factors, demographic and clinical characteristics of 2019-nCoV infections were explored.Results:A total of 28 901 valid questionnaires were obtained (26 355 from students and 2 546 from staff) with a qualified rate of 94.3%. The infection rates varied greatly among provinces and cities; the infection rates in students and staff in Beijing reached 78.55% and 76.40%, respectively. Infection rates in students and staff in Tianjin and Hebei also exceeded 65.00%, and 96.76% of infections occurred on and after December 1, 2022. Students had lower risk for the infection compared with staff ( OR=0.72, 95% CI: 0.60-0.86). Compared with age group ≤20 years, the OR of age groups 21-30, 31-40, 41-50, 51-60 and > 60 years were 1.22 (95% CI: 1.14-1.30), 1.54 (95% CI: 1.30-1.84), 1.25 (95% CI: 0.99-1.58), 1.29 (95% CI: 0.94-1.78) and 1.19 (95% CI: 0.51-2.80), respectively. The longer the period after the last vaccination, the higher the risk for the infection. Compared with those who received the last vaccination in the past 3 months, the OR of those who received the last vaccination in the past 4-6 months, 7-9 months, 10-12 months, 13-15 months and ≥16 months were 1.56 (95% CI: 1.34-1.82), 1.59 (95% CI: 1.36-1.86), 1.67 (95% CI: 1.45-1.93), 1.86 (95% CI:1.58-2.19) and 2.46 (95% CI: 2.09-2.90), respectively. Compared with those living alone, the OR of those living with 1-2, 3-4 and ≥5 roommates were 17.55 (95% CI: 15.91-19.39), 20.22 (95% CI: 18.25-22.43) and 11.78 (95% CI: 10.40-13.36), respectively. Only 5.94% of the staff and 7.19% of the students reported asymptomatic infections. Among those with symptoms, 88.18% of students and 85.65% of staff reported symptom of fever. Conclusions:The transmission dynamics of 2019-nCoV infection varied significantly across the country. The speed of transmission of 2019-nCoV and clinical severity of the infection were far beyond our knowledge. Organized epidemiological survey should be regularly carried out to provide reliable data support for more accurate prediction of the epidemic and medical resource allocation.

Objective:To analyze the factors influencing functional recovery after surgery of calcaneal fracture.Methods:A retrospective analysis was performed in 1,080 eligible patients with calcaneal fracture who had been admitted to The Third Hospital of Hebei Medical University from January 1, 2018 to December 31, 2020. They were 931 males and 149 females with a mean age of 43.0 years. By the Sanders classification, there were 107 cases of type Ⅰ, 343 cases of type Ⅱ, 471 cases of type Ⅲ and 159 cases of type Ⅳ. Multiple linear regression model was used to screen out the main relevant factors affecting the postoperative functional recovery by analyzing the 18 factors which might influence the postoperative functional recovery like gender, age, Sanders type, occupation, body mass index, season, cause, hospital stay, operation method, internal fixation, preoperative combined injury, preoperative complication, anesthesia, attendance to rehabilitation institution, incision selection, waiting time, preoperative blister and reduction quality.Results:All the 1,080 patients were followed up for 17.5 months on average. The mean Creighton-Nebraska score at the last follow-up was 88.4. The univariate analyses showed statistically significant differences in the Creighton-Nebraska score among patients with different gender, age group, Sanders type, occupation, injury cause, surgical method, preoperative combined injury, incision selection and reduction quality ( P<0.05). Multiple linear regression model analysis resulted in the following regression equation: Y=107.408-4.013×gender-7.101×age-1.214×Sanders type-1.606×incision selection. Conclusions:The factors which influence the functional recovery after surgery of calcaneal fracture may be gender, age, fracture type and incision selection; the functional recovery score after surgery of calcaneal fracture may be low for female senior patients with type Ⅳ fracture and a large L-shaped incision.