Objective:To study the current status of longitudinal extrauterine growth restriction (EUGR) in extremely preterm infants (EPIs) and to develop a prediction model based on clinical data from multiple NICUs.Methods:From January 2017 to December 2018, EPIs admitted to 32 NICUs in North China were retrospectively studied. Their general conditions, nutritional support, complications during hospitalization and weight changes were reviewed. Weight loss between birth and discharge > 1SD was defined as longitudinal EUGR. The EPIs were assigned into longitudinal EUGR group and non-EUGR group and their nutritional support and weight changes were compared. The EPIs were randomly assigned into the training dataset and the validation dataset with a ratio of 7∶3. Univariate Cox regression analysis and multiple regression analysis were used in the training dataset to select the independent predictive factors. The best-fitting Nomogram model predicting longitudinal EUGR was established based on Akaike Information Criterion. The model was evaluated for discrimination efficacy, calibration and clinical decision curve analysis.Results:A total of 436 EPIs were included in this study, with a mean gestational age of (26.9±0.9) weeks and a birth weight of (989±171) g. The incidence of longitudinal EUGR was 82.3%(359/436). Seven variables (birth weight Z-score, weight loss, weight growth velocity, the proportion of breast milk ≥75% within 3 d before discharge, invasive mechanical ventilation ≥7 d, maternal antenatal corticosteroids use and bronchopulmonary dysplasia) were selected to establish the prediction model. The area under the receiver operating characteristic curve of the training dataset and the validation dataset were 0.870 (95% CI 0.820-0.920) and 0.879 (95% CI 0.815-0.942), suggesting good discrimination efficacy. The calibration curve indicated a good fit of the model ( P>0.05). The decision curve analysis showed positive net benefits at all thresholds. Conclusions:Currently, EPIs have a high incidence of longitudinal EUGR. The prediction model is helpful for early identification and intervention for EPIs with higher risks of longitudinal EUGR. It is necessary to expand the sample size and conduct prospective studies to optimize and validate the prediction model in the future.

Objective:To evaluate the role of reactive oxygen species (ROS) in attenuation of hypoxia-reoxygenation (H/R) injury in rat cardiomyocytes by pinacidil postconditioning and the relationship with nuclear factor erythrid 2-related factor 2 (Nrf2)-antioxidant response element (ARE) signaling pathway.Methods:Adult rat cardiomyocytes were isolated and cultured and then divided into 4 groups ( n=20 each) by a random number table method: control group (group C), H/R group, pinacidil postconditioning group (group P) and reactive oxygen scavenger N-(2-mercaptopropionyl)-glycine(MPG)+ pinacidil postconditioning group (group MPG+ P). Group C was continuously exposed to 95%O 2+ 5%CO 2 in an incubator at 37 ℃ for 105 min. The cells were exposed to 5%CO 2+ 1%O 2+ 94%N 2 in an incubator at 37 ℃ for 45 min followed by reoxygenation for 60 min to prepare H/R injury model. The cells were exposed to hypoxia for 45 min and then treated with pinacidil 50 μmol/L for 5 min followed by reoxygenation for 60 min in group P. The cells were exposed to hypoxia for 45 min, treated with MPG 2 mmol/L for 10 min, and then treated with pinacidil for 5 min followed by reoxygenation for 60 min in group MPG+ P. The content of Ca 2+ and activity of Nrf2 in cardiomyocytes were measured at the end of reoxygenation. The ultrastructure of cardiomyocytes was observed, and mitochondrial ultrastructure was evaluated using mitochondrial Flameng score. The expression of Nrf2, superoxide dismutase (SOD1), quinone oxidoreductase 1 (NQO1), and heme oxygenase 1 (HO-1) protein and mRNA was detected using Western blot and real-time polymerase chain reaction. Results:Compared with group C, the Ca 2+ content, Nrf2 activity and mitochondrial Flameng score were significantly increased, the expression of Nrf2, SOD1, NQO1 and HO-1 protein and mRNA was down-regulated ( P<0.05), and the damage to the ultrastructure of cardiomyocytes was aggravated in group H/R. Compared with H/R group, the Ca 2+ content and mitochondrial Flameng score were significantly decreased, the Nrf2 activity was increased, the expression of Nrf2, SOD1, NQO1 and HO-1 protein and mRNA was up-regulated ( P<0.05), and the damage to the ultrastructure of cardiomyocytes was attenuated in P group. Compared with P group, the Ca 2+ content and mitochondrial Flameng score were significantly increased, the Nrf2 activity was decreased, the expression of Nrf2, SOD1, NQO1 and HO-1 protein and mRNA was down-regulated ( P<0.05), and the damage to the ultrastructure of cardiomyocytes was aggravated in MPG+ P group. Conclusions:ROS is involved in attenuation of H/R injury by pinacidil postconditioning, which is associated with activation of the Nrf2-ARE signaling pathway in rat cardiomyocytes.

To investigate the effects of ORF9 gene of porcine circovirus type 2(PCV2)on PK-15,eu-karyotic expression plasmid was constructed and transfected into PK-15 cells,and the effects of overexpression of ORF9 on proliferation,apoptosis and immunization of PK-15 cells were exam-ined by flow cytometry and qRT-PCR.The results showed that ORF9 gene overexpression signifi-cantly up-regulated the expression levels of the ER stress marker gene GRP78,increased the num-ber of S phase cells,accelerated cell cycle progression,increased the apoptosis rate of PK-15 cells,up-regulated the expression levels of apoptosis-related genes caspase-3,caspase-8,caspase-9,p53 and Bax(P＜0.01),down-regulated the expression levels of apoptosis-related genes Bcl-2,up-reg-ulated the expression levels of immune-related genes 1L-8,IL-10,NF-κB and TNF-α(P＜0.01),and down-regulated the expression levels of immune-related genes IL-2,IFN-β and IL-12(P＜0.01).The above results indicate that ORF9 gene may promote the proliferation and apoptosis of PK-15 cells and play a role in the escape process of PK-15 cells.

In order to understand the genomic characteristics and genetic variation and strain type of infectious bursal disease virus(IBDV)isolate GZGY2022,which caused the death of chickens in Guizhou farm,primers were designed to amplify the whole genome of the isolate,and genetic evo-lution and strain type analysis were performed after cloning and sequencing.The results showed that the A and B segments of IBDV genome were 3 260,2 827 bp,respectively,encoding VP2-VP5 and VP1 genes.The nucleotide sequence homology between the A and B segments of this strain and the VvIBDV were 96.2％-98.7％and 87.7％-98.9％,respectively,which is the highest with NN1172 strain,83.1％-94.7％and 90.1％-91.0％with other strains.The results of genetic evolution and strain type study showed that IBDV strains can be divided into 6 branches according to antigen and virulence,and the A and B segments of the strain were clustered in the evolutionary branch of VvIBDV,and the strain was A3B3 genotype according to the new genotype classification method.The results of amino acid sequence analysis showed that there were 3 and 7 unique amino acid site variations in the A and B segments of the strain,respectively,and 13 unique characteristic amino acid sites in the coding region of the full-length genome were consistent with VvIBDV.The VP2 sequence of segment A has 19 characteristic amino acid identical with VvIBDV,among which hyper variable regions 222A,242I,253Q,256I,279D,284A,294I and 299S were characteristic ami-no acid sites of the VvIBDV,and the heptapeptide region sequence SWSASGS was consistent with the virulent strain.The VP1 sequence of segment B has 10 characteristic amino acid identical with VvIBDV,among which 61I,145T and 287A were the characteristic amino acid sites of the VvIB-DV.In addition,the nucleotide sequence GGTGCC of 777-782 did not form the restriction endo-nuclease site of Kpn Ⅰ,and combined with the triplet site 145/146/147(TEG),the segment B was consistent with the NN1172 strain,showed that its virulence was slightly weaker than that of the B2 strain of VvIBDV.The results of recombination analysis showed that there were no breaks and recombination sites in the sequence of the strain,and no recombination event occurred.In summa-ry,this study found that GZGY2022 strain belonged to the A3B3 genotype non-recombinant VvIB-DV strain,and its special amino acid sites were consistent with the molecular characteristics of VvIBDV.This study lays the foundation for further exploring the genomic characteristics and path-ogenicity of VvIBDV.

Objective To analyze the prevalence trend of chronic hepatitis C and liver function impairment in Taixi area from 2018 to 2021, and to provide theoretical basis for preventing liver function impairment in hepatitis C patients in Taixi area. Methods The data of hepatitis C cases reported in Taixi were downloaded from the infectious disease reporting Information management system of Chinese Center for Disease Control and Prevention, and the epidemiological characteristics of hepatitis C were analyzed by descriptive epidemiological methods. The clinical data including gender, age, place of residence, smoking history, drinking history, therapeutic drugs, genotyping and other clinical data were collected from HIS system of the hospital. Patients were divided into liver function injury group and control group according to whether they had liver function injury. Univariate analysis and logistic regression were used to analyze the factors of liver function injury in hepatitis C patients in Taixi area. Results Among the 550 cases reported from 2018 to 2021, there were no deaths, including 292 males and 258 females. The male cases were more than the female cases, and the average age was (53.47±5.74) years old. There was no significant difference in the composition of male and female cases among different age groups (χ²=1.472,P>0.05). From 2018 to 2021, the proportion of patients aged 40 to 59 was significantly higher than that of patients aged 20 to 39 and ≥60. The occupation composition was mainly farmers, accounting for 44.36% (244/550), and 287 cases (52.18%) lived mainly in rural areas. From 2018 to 2021, 129 (23.45%) of 550 patients with hepatitis C had liver function injury. ALT, AST and GGT values in the liver function injury group were significantly higher than those in the control group (P<0.05). The ALB value of liver function injury group was significantly lower than that of control group (P<0.05). There were statistically significant differences between the two groups in mean age, drinking history, diabetes mellitus, genotyping, HCV-RNA viral load, CD4+CD25+Treg (P<0.05). CD4+CD25+Treg>5%, genotype 1b and high load of HCV-RNA were independent risk factors for liver function impairment in hepatitis C patients in Taixi area (P<0.05). Conclusion The incidence of hepatitis C was high in Taixi area from 2018 to 2021, and patients with CD4+CD25+Treg<5%, genotype 1b and high load of HCV-RNA had a high risk of liver function impairment. Therefore, active treatment should be carried out to reduce the occurrence of liver function injury.

Objective:To evaluate the role of succinate dehydrogenase (SDH) in hypoxic postconditioning (HPC)-induced reduction of hypoxia-reoxygenation (H/R) injury in myocardial cells of rats and the relationship with mitochondrial ATP-sensitive potassium channels (mito-K ATP). Methods:Myocardial cells isolated from adult male Sprague-Dawley rats were cultured for 48 h and then divided into 7 groups ( n=24 each) using a random number table method: blank control group (Nor group), H/R group, SDHA-siRNA adenovirus+ H/R group (siRNA+ H/R group), HPC group, SDHA-siRNA adenovirus+ HPC group (siRNA+ HPC group), 5-HD+ HPC group, and SDHA-siRNA adenovirus+ 5-HD+ HPC group (siRNA+ 5-HD+ HPC group). Nor group was continuously cultured for 195 min under normoxic conditions. The H/R injury model was prepared by exposing the cells to hypoxia for 45 min in 5% CO 2 + 1% O 2 + 94% N 2, followed by reoxygenation for 150 min. The HPC method involved three cycles of 5 min reoxygenation/5 min hypoxia at the end of 45 min ischemia before 120 min reoxygenation. The mito-K ATP blocker 5-HD administration method involved adding 5-HD at a final concentration of 100 μmol/L at 30 min of hypoxia. The myocardial cells in each siRNA group were successfully transfected with SDHA-siRNA adenovirus to silence SDHA expression. The cell viability, calcium ion level, SDH activity, ATP content, degree of mitochondrial permeability transition pore (mPTP) opening, and mitochondrial membrane potential (MMP) were measured at the end of reoxygenation. Results:Compared with Nor group, the cell viability, ATP content and MMP were significantly decreased, and the degree of mPTP opening, level of calcium ion and activity of SDH were increased in H/R group ( P<0.05). Compared with H/R group, the cell viability, ATP content and MMP were significantly increased, and the degree of mPTP opening, calcium ion level and SDH activity were decreased in siRNA+ H/R group and HPC group ( P<0.05). Compared with HPC group, the cell viability, ATP content and MMP were significantly decreased, and the degree of mPTP opening, calcium ion level and SDH activity were increased in 5-HD+ HPC group ( P<0.05), and the cell viability, ATP content and MMP were significantly increased, and the degree of mPTP opening, calcium ion level and SDH activity were decreased in siRNA+ HPC group ( P<0.05). Compared with siRNA+ HPC group, the cell viability, ATP content and MMP were significantly decreased, the opening degree of mPTP and calcium ion level were increased ( P<0.05), and no significant change was found in the SDH activity in siRNA+ 5-HD+ HPC group ( P>0.05). Compared with 5-HD+ HPC group, the SDH activity was significantly decreased, and no significant change was found in the other parameters in siRNA+ 5-HD+ HPC group ( P>0.05). Conclusions:HPC alleviates H/R injury probably by reducing SDH activity and opening mito-K ATP in myocardial cells of rats.

Objective:To investigate the diagnostic accuracy of serological indicators and evaluate the diagnostic value of a new established combined serological model on identifying the minimal hepatic encephalopathy (MHE) in patients with compensated cirrhosis.Methods:This prospective multicenter study enrolled 263 compensated cirrhotic patients from 23 hospitals in 15 provinces, autonomous regions and municipalities of China between October 2021 and August 2022. Clinical data and laboratory test results were collected, and the model for end-stage liver disease (MELD) score was calculated. Ammonia level was corrected to the upper limit of normal (AMM-ULN) by the baseline blood ammonia measurements/upper limit of the normal reference value. MHE was diagnosed by combined abnormal number connection test-A and abnormal digit symbol test as suggested by Guidelines on the management of hepatic encephalopathy in cirrhosis. The patients were randomly divided (7∶3) into training set ( n=185) and validation set ( n=78) based on caret package of R language. Logistic regression was used to establish a combined model of MHE diagnosis. The diagnostic performance was evaluated by the area under the curve (AUC) of receiver operating characteristic curve, Hosmer-Lemeshow test and calibration curve. The internal verification was carried out by the Bootstrap method ( n=200). AUC comparisons were achieved using the Delong test. Results:In the training set, prevalence of MHE was 37.8% (70/185). There were statistically significant differences in AMM-ULN, albumin, platelet, alkaline phosphatase, international normalized ratio, MELD score and education between non-MHE group and MHE group (all P<0.05). Multivariate Logistic regression analysis showed that AMM-ULN [odds ratio ( OR)=1.78, 95% confidence interval ( CI) 1.05-3.14, P=0.038] and MELD score ( OR=1.11, 95% CI 1.04-1.20, P=0.002) were independent risk factors for MHE, and the AUC for predicting MHE were 0.663, 0.625, respectively. Compared with the use of blood AMM-ULN and MELD score alone, the AUC of the combined model of AMM-ULN, MELD score and education exhibited better predictive performance in determining the presence of MHE was 0.755, the specificity and sensitivity was 85.2% and 55.7%, respectively. Hosmer-Lemeshow test and calibration curve showed that the model had good calibration ( P=0.733). The AUC for internal validation of the combined model for diagnosing MHE was 0.752. In the validation set, the AUC of the combined model for diagnosing MHE was 0.794, and Hosmer-Lemeshow test showed good calibration ( P=0.841). Conclusion:Use of the combined model including AMM-ULN, MELD score and education could improve the predictive efficiency of MHE among patients with compensated cirrhosis.

Objective:To compare the differences in the prevalence of mild micro-hepatic encephalopathy (MHE) among patients with cirrhosis by using the psychometric hepatic encephalopathy score (PHES) and the Stroop smartphone application (Encephal App) test.Methods:This prospective, multi-center, real-world study was initiated by the National Clinical Medical Research Center for Infectious Diseases and the Portal Hypertension Alliance and registered with International ClinicalTrials.gov (NCT05140837). 354 cases of cirrhosis were enrolled in 19 hospitals across the country. PHES (including digital connection tests A and B, digital symbol tests, trajectory drawing tests, and serial management tests) and the Stroop test were conducted in all of them. PHES was differentiated using standard diagnostic criteria established by the two studies in China and South Korea. The Stroop test was evaluated based on the criteria of the research and development team. The impact of different diagnostic standards or methods on the incidence of MHE in patients with cirrhosis was analyzed. Data between groups were differentiated using the t-test, Mann-Whitney U test, and χ2 test. A kappa test was used to compare the consistency between groups. Results:After PHES, the prevalence of MHE among 354 cases of cirrhosis was 78.53% and 15.25%, respectively, based on Chinese research standards and Korean research normal value standards. However, the prevalence of MHE was 56.78% based on the Stroop test, and the differences in pairwise comparisons among the three groups were statistically significant (kappa = -0.064, P < 0.001). Stratified analysis revealed that the MHE prevalence in three groups of patients with Child-Pugh classes A, B, and C was 74.14%, 83.33%, and 88.24%, respectively, according to the normal value standards of Chinese researchers, while the MHE prevalence rates in three groups of patients with Child-Pugh classes A, B, and C were 8.29%, 23.53%, and 38.24%, respectively, according to the normal value standards of Korean researchers. Furthermore, the prevalence rates of MHE in the three groups of patients with Child-Pugh grades A, B, and C were 52.68%, 58.82%, and 73.53%, respectively, according to the Stroop test standard. However, among the results of each diagnostic standard, the prevalence of MHE showed an increasing trend with an increasing Child-Pugh grade. Further comparison demonstrated that the scores obtained by the number connection test A and the number symbol test were consistent according to the normal value standards of the two studies in China and South Korea ( Z = -0.982, -1.702; P = 0.326, 0.089), while the other three sub-tests had significant differences ( P < 0.001). Conclusion:The prevalence rate of MHE in the cirrhotic population is high, but the prevalence of MHE obtained by using different diagnostic criteria or methods varies greatly. Therefore, in line with the current changes in demographics and disease spectrum, it is necessary to enroll a larger sample size of a healthy population as a control. Moreover, the establishment of more reliable diagnostic scoring criteria will serve as a basis for obtaining accurate MHE incidence and formulating diagnosis and treatment strategies in cirrhotic populations.

Objective:To explore the application effect of the auxiliary teaching mode based on WeChat Official Platform in pathology teaching.Methods:With the help of WeChat Official Platform, the "Pathology Experimental Course Platform of Qiqihar Medical University" (bilingual) was designed and formed. For the international students in the experimental group, teachers designed, developed and generated teaching resources in advance according to the requirements of pathology syllabus for international students and teaching contents, and post them on the platform. At the end of the term, they had pathology examination with the same difficulty as the control group, and their results were comparatively analyzed. Meanwhile, a questionnaire survey was designated to evaluate the teaching process and effects, to find out whether the platform work for the students to obtain more extracurricular knowledge and improve learning efficiency. SPSS 19.0 was used for t test. Results:Compared with the control group [(7.56±0.12) points and (53.20±0.70) points], the experimental group's scores of experimental assessment [(8.59±0.13) points] increased significantly ( P<0.05), and the scores of theoretical assessment [(56.23±0.60) points] also increased significantly ( P<0.05). Conclusion:With the help of the WeChat Official Platform, the auxiliary teaching mode breaks the limitation of time and space, enables foreign students to study and observe more actively, consolidates basic theoretical knowledge, strengthens the ability to observe disease lesions and clinical thinking ability, promotes international students' understanding of the relationship between pathological changes and clinical symptoms and signs, and improves their academic performances.

Objective:To evaluate the role of reactive oxygen species (ROS) in hypoxia postconditioning-induced activation of nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE) signaling pathway in rat cardiomyocytes.Methods:Primary cardiomyocytes of adult rats were isolated and cultured and divided into 4 groups ( n=20 each) using a random number table method: normal group (group N), hypoxia-reoxygenation group (group HR), hypoxia postconditioning group (group HPO) and hypoxia postconditioning plus an ROS scavenger N-(2-Amidinopropionyl)-glycine (MPG) group (group HPO+ MPG). Cells were exposed to hypoxia for 45 min followed by 60 min reoxygenation to develop the cardiomyocyte hypoxia-reoxygenation injury model.In HPO group, cells were subjected to 3 cycles of 5-min hypoxia/5-min reoxygenation after 45 min hypoxia, followed by reoxygenation for 60 min.In HPO+ MPG group, MPG (final concentration 2 mmol/L) was added at 35 min of hypoxia, cells were subjected to hypoxia for 10 min, and the other treatments were similar to those previously described in group HPO.At the end of reoxygenation, the intracellular calcium level and Nrf2 activity were measured, the ultrastructure of cardiomyocytes was observed, and the Flameng score of mitochondria was assessed, and the expression of Nrf2, NAD(P)H quinine oxidoreductase 1 (NQO1), superoxide dismutase 1 (SOD1) and heme oxygenase-1 (HO-1) protein and mRNA was detected using real-time polymerase chain reaction and Western blot. Results:Compared with group N, the intracellular free Ca 2+ level, Nrf2 activity and Flameng score were significantly increased, and the expression of Nrf2, NQO1, SOD1 and HO-1 protein and mRNA was down-regulated in group HR ( P<0.05). Compared with group HR, the intracellular free Ca 2+ level and Flameng score were significantly decreased, the Nrf2 activity was increased, and the expression of Nrf2, NQO1, SOD1 and HO-1 protein and mRNA was up-regulated in group HPO ( P<0.05). Compared with group HPO, the intracellular free Ca 2+ level and Flameng score were significantly increased, the Nrf2 activity was decreased, and the expression of Nrf2, NQO1, SOD1 and HO-1 protein and mRNA was down-regulated in group HPO+ MPG ( P<0.05). Conclusions:The mechanism by which hypoxia postconditioning activates the Nrf2/ARE signaling pathway in rat cardiomyocytes may be related to ROS.