BACKGROUND:Erythropoietin has anti-inflammatory,anti-apoptotic,and pro-bone defect repair effects.To date,fewer studies have been conducted on its effects and molecular mechanism underlying restorative dentin formation after pulp injury. OBJECTIVE:To explore the effect of erythropoietin on restorative dentin formation after pulp injury. METHODS:(1)Animal experiment:Thirty-two rats were randomly divided into control group(n=16)and experimental group(n=16).In the experimental group,collagen sponges containing erythropoietin were used to directly cap the pulp at the pulp injury,and in the control group,collagen sponges containing PBS were used to directly cap the pulp at the exposed pulp injury.The cavity was then closed with glass ionomer adhesive.After 2 and 4 weeks of treatment,the maxillary bones of the two groups were collected,and the expression of nestin in dentin was detected by immunohistochemistry,and the reparative dentin production was observed by hematoxylin-eosin staining.The maxillae of four Sprague-Dawley rats were taken for immunohistochemical detection of erythropoietin expression in molar and incisor teeth.(2)Cell experiment:Human dental pulp cells,human periodontal ligament cells and human gingival fibroblasts were obtained from human dental tissue,periodontal ligament,and gingival tissue.Real-time reverse transcription PCR(RT-PCR)was used to detect the mRNA expression of erythropoietin.Erythropoietin,dentin sialophosphoprotein,dentin matrix protein 1,and nestin mRNA levels in human pulp cells were detected by RT-PCR under induced or uninduced odontoblastic differentiation.After down-regulation of erythropoietin expression or exogenous administration of erythropoietin intervention under induced or uninduced differentiation odontoblastic differentiation,the relative mRNA expression of dentin sialophosphoprotein and dentin matrix protein 1 in human pulp cells was detected by RT-PCR,and the formation of mineralized nodules was detected by alizarin red S staining,and mRNA and protein expressions of bone morphogenetic protein 2 were detected by RT-PCR and western blot,respectively. RESULTS AND CONCLUSION:(1)Animal experiment:Compared with the control group,the restorative dentin production and nestin expression were higher in the experimental group after 2 and 4 weeks of treatment.The expression of erythropoietin was weakly positive in pulp,odontoblastic cell layer and periodontal membrane of the rat's first maxillary molar,and strongly positive in odontoblasts.(2)Cell experiment:The mRNA expression of erythropoietin was higher in human dental pulp cells than in the other two types of cells.The mRNA expressions of dentin sialophosphorin,dentin matrix protein 1,nestin,erythropoietin and bone morphogenetic protein 2 in human pulp cells increased and the formation of mineralized nodules during odontoblastic differentiation under induction compared with non-induction conditions.The mRNA expression of dentin sialophosphoprotein,dentin matrix protein 1,nestin,bone morphogenetic protein 2 and the formation of mineralized nodules were decreased in human pulp cells after downregulation of erythropoietin under induced odontoblastic differentiation,and the protein expression of bone morphogenetic protein 2 was also decreased.After exogenous erythropoietin intervention,the expression of the above indexes in human dental pulp cells increased.To conclude,erythropoietin can promote the formation of dentin to some extent.

Objective To investigate the impacts of wogonin(WG)on Th17/Treg cell balance in autoimmune hep-atitis(AIH)rats.Methods A total of 10 rats were randomly selected as the control group.The remaining rats were injected with concanavalin A(ConA,12.5 mg/kg)solution via tail vein to construct AIH model rat,which were ran-domly divided into AIH group,L-WG group(10 mg/kg),M-WG group(20 mg/kg),H-WG group(30 mg/kg),H-WG+VPA group(30 mg/kg WG+300 mg/kg Notch signal pathway activator VPA),10 rats in each group and administered once a day for 10 days.Serum inflammatory factors and liver function indexes were detected by ELISA;HE staining was used to observe the pathological morphology of liver tissue;the level of spleen Th17/Treg cells was detected by flow cytometry;Western blot was used to detect the expression of spleen retinoid acid related orphan receptor γ t(RORγt),fork head box protein P3(Foxp3)and liver Notch signal pathway proteins.Results The liver tissue structure of control group was normal and the staining was clear;In AIH group,the cells of liver tis-sue showed edema,the increase of cell volume led to the compression and narrowing of liver sinuses,and a large number of inflammatory cell infiltration and a small amount of necrosis occurred.The contents of alanine aminotrans-ferase(ALT),aspartate aminotransferase(AST),interleukin(IL)-17 and IL-23,level of Th17 cells,Th17/Treg,the expression of RORγt,Notch,hes family bHLH transcription factor 1 gene(HES1)and hes related family bHLH transcription factor with YRPW motif 1(HEY1)protein in AIH group were greatly higher than those in control group(P＜0.05),the contents of IL-10 and TNF-β,level of Treg cells,and level of Foxp3 protein were greatly lower(P＜0.05);Compared with AIH group,the liver injury in L-WG group,M-WG group and H-WG group was im-proved,the contents of ALT,AST,IL-17 and IL-23,level of Th17 cells,Th17/Treg,the expression of RORγt,Notch,HES1 and HEY1 protein were greatly lower(P＜0.05),the contents of IL-10 and TNF-β,level of Treg cells,and level of Foxp3 protein were greatly higher(P＜0.05);VPA reversed the improvement effect of H-WG on AIH rats.Conclusions WG could promote Th17/Treg cell balance in AIH rats by down-regulating Notch signal pathway.

Objective To investigate the effect of ursodeoxycholic acid(UDCA)on the symptoms after severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)infection in patients with primary biliary cholangitis(PBC)and their family member.Methods A questionnaire survey was conducted to collect related information from 171 PBC patients who attended The First Affiliated Hospital of Air Force Medical University before March 22,2023 and 128 family members,including demographic information,comorbidities,UDCA administration,SARS-CoV-2 infection,vaccination,symptoms,therapeutic medication,and the changes in liver disease-related symptoms.The independent-samples t test or the Mann-Whitney U test was used for comparison of continuous data between two groups,and the chi-square test or the Fisher's exact test was used for comparison of categorical data between two groups.Results The median age was 51 years in the PBC patients and 49 years in the family members,with no significant difference between the two groups(P>0.05).Compared with the family member group,the PBC group had significantly lower body mass index(22.2±2.4 kg/m2 vs 23.3±2.9 kg/m2,P<0.001)and proportion of male individuals(10%vs 55%,P<0.001).All PBC patients received UDCA at a dose of 13—15 mg/kg,and SARS-CoV-2 infection rate was 100%in both groups.The family members had a significantly higher SARS-CoV-2 vaccination rate than the PBC patients(91%vs 57%,P<0.001).Compared with the family members,the PBC patients had significantly milder symptoms of sneezing,nasal obstruction,chest pain,and abnormal taste(P<0.05).Compared with the family members,the PBC patients had significantly lower rates of use of compound cold medicine(11%vs 20%,P<0.05)and Lianhua Qingwen capsules(12%vs 21%,P<0.05).For the PBC patients after SARS-CoV-2 infection,the liver disease-related symptoms such as fatigue,abdominal distension,dry mouth and dry eyes,pruritus,and yellow skin were aggravated by 37%,2%,27%,10%,and 3%,respectively.Conclusion Compared with the immediate family members of PBC patients who do not take UDCA,the PBC patients receiving UDCA do not show a reduction in SARS-CoV-2 infection rate,but UDCA may have a certain effect on alleviating infection-related symptoms in such patients.PBC patients may still experience the aggravation of liver disease-related symptoms after SARS-CoV-2 infection,and the long-term effect on PBC patients after SARS-CoV-2 infection should be taken seriously in clinical practice.

ObjectiveTo investigate the mechanism of Huazhuo Jiedu Huoxue Tongluo prescription in alleviating cerebral ischemia-reperfusion injury via regulating nerve cell autophagy based on c-Jun N-terminal kinase（JNK）signaling pathway . MethodSixty SD rats were randomly divided into 6 groups： sham group， middle cerebral artery occlusion/reperfusion （MCAO/R） group （model group）， Huazhuo Jiedu Huoxue Tongluo prescription group ［traditional Chinese medicine （TCM） group（25.0 g·kg^-1）］， JNK inhibitor SP600125 （SP） group（5 mg·kg^-1）， TCM+SP group and JNK agonist Anisomycin （Ani） group（15 mg·kg^-1）. After 24 h of modeling， TCM group and TCM+SP group were given TCM decoction （ig） for 3 consecutive days， and the other groups were given equal volume of normal saline （ig）. Neurological deficit was evaluated by neurological function score and cerebral infarct volume was determined by 2，3，5-triphenyltetrazole chloride （TTC） staining. Hematoxylin-eosin （HE） staining and Nissl staining were used to observe the structural changes of brain tissue and the damage of neurons， respectively. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay （TUNEL） was performed to detect cell apoptosis. The ultrastructure of autophagosomes was observed by transmission electron microscope. Western blot was employed to detect the protein expressions of microtubule-associated protein 1 light chain 3A/B （LC3A/B）， autophagy related 5 （Atg5）， the ortholog of yeast Atg6 （Beclin1）， p62， B-cell lymphoma 2 （Bcl-2）， JNK， phosphorylated （p）-JNK and c-Jun in brain tissue. The mRNA expressions of LC3A/B， Beclin1， p62， Atg5， Bcl-2， JNK and c-Jun were detected by Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR）. ResultCompared with the sham group， the model group had elevated neurological deficit score （P<0.05）， enlarged cerebral infarct volume （P<0.05）and typical infarction manifestations formed in hippocampal region and its surrounding brain tissue. In addition， there were a large number of neuronal cell degeneration， necrosis， liquefaction， nucleus pyknosis and deep staining， and inflammatory cell infiltration in the cortex in the model group， and severe swelling of mitochondria， lysosomes， autophagosomes and autophagolysosomes were clearly seen under electron microscope. TUNEL positive cells were increased （P<0.05）， and cell apoptosis was severe. The nuclear membrane and nucleolus of neurons in brain tissue were blurred with discontinuous processes， and Nissl bodies in cytoplasm were stained light with reduced number. Western blot revealed that the model group had up-regulated protein expressions of LC3A/B， Beclin1， Atg5， JNK， p-JNK and c-Jun in brain tissue （P<0.05）， while down-regulated protein expressions of p62 and Bcl-2 （P<0.05）as compared with the sham group. Real-time PCR indicated that the mRNA expressions of LC3A/B， Beclin1， Atg5， JNK and c-Jun in the model group were higher （P<0.05） while the mRNA expressions of p62 and Bcl-2 were lower （P<0.05） than those in the sham group. Compared with the conditions in model group， the neurological deficit scores of TCM， SP and TCM+SP groups were lowered （P<0.05）， and the cerebral infarct volume was reduced （P<0.05）， with improved pathological status of brain tissue， especially in the TCM group. Furthermore， there were abundant and basically normal mitochondrial cristae， slightly dilated endoplasmic reticulum， slightly swollen golgi apparatus， slightly fused nuclear membrane， and few visible lysosomes， autophagosomes and autophagolysosomes. TUNEL positive cells were decreased （P<0.05）， displaying reduced apoptosis， especially in the TCM group. The nucleolus and nuclear membrane of neurons in brain tissue were discernible， and Nissl bodies in cytoplasm was reduced to a certain degree as compared with those in the model group. Western blot showed a decrease in the protein expressions of LC3A/B， Beclin1， Atg5， JNK， p-JNK and c-Jun in the TCM group ，the SP group，and the TCM+SP group（P<0.05），while an increase in the protein expressions of p62 in the TCM group and SP group（P<0.05），and an increase in the protein expressions of Bcl-2 in the TCM group and TCM+SP group. By Real-time PCR， the mRNA expressions of LC3A， LC3B， Beclin1， Atg5， JNK and c-Jun had a down-regulation（P<0.05） while the mRNA expression of p62 a up-regulation in the TCM group ，the SP group，and the TCM+SP group（P<0.05），and the mRNA expression of Bcl-2 a up-regulation in the TCM group and the TCM+SP group（P<0.05）.Scores of the Ani group were raised （P<0.05）， and infarct volume was increased significantly， with aggravated neuronal cell necrosis and obvious inflammatory infiltration. Moreover， there were neuronal nuclear membrane fusion with abnormal protrusion， increased heterochromatin aggregation in edge， severe mitochondrial swelling， endoplasmic reticulum expansion， increased lysosomes， increased intracytoplasmic vesicles， and visible autophagosomes and autophagolysosomes. TUNEL positive cells were increased （P<0.05）， representing severe apoptosis. The number of Nissl bodies dropped with light staining， and the nucleolus and nuclear membrane were blurred. Real-time PCR found that the mNRA expressions of Atg5， c-Jun， JNK were up-regulated （P<0.05），while Beclin1， p62， Bcl-2 were were down-regulated in the Ani group （P<0.05）. Compared with the TCM group and SP group，the protein expressions of LC3A/B， Beclin1， Atg5， JNK， p-JNK， c-Jun were decreased，and p62， Bcl-2 were increased in the Ani group（P<0.05）. Compared with the TCM group，the mRNA expressions of JNK mRNA had a down-regulation in the SP group and TCM+SP group，while LC3A， LC3B， Atg5， c-Jun， JNK had an up-regulation（P<0.05） and Bcl-2 had a down-regulation in the Ani group（P<0.05）. Compared with the SP group，the mRNA expressions of Atg5， c-Jun， JNK had an up-regulation（P<0.05）， and Beclin1， p62， Bcl-2 had a down-regulation in the Ani group（P<0.05）. ConclusionHuazhuo Jiedu Huoxue Tongluo prescription significantly up-regulates the protein and mRNA expressions of LC3A/B， Beclin1， Atg5， JNK， p-JNK and c-Jun， and down-regulates the protein and mRNA expressions of p62 and Bcl-2， suggesting that the prescription can inhibit autophagy through JNK signaling pathway to reduce ischemia/reperfusion injury in rats.

Objective:To explore the relevant predictive indicators of fever course > 7 days in children with infectious mononucleosis.Methods:The clinical data of 163 children with infectious mononucleosis who received treatment in Xi'an Children's Hospital from January 2018 to October 2020 were retrospectively analyzed. According to the heat duration, the children were divided into the fever course > 7 days group ( n = 55) and the fever course ≤ 7 days group ( n = 108). The clinical manifestations and laboratory indexes on admission were compared between the two groups. A logistic regression model was used to analyze the influential factors of fever course in children. A receiver operating curve was used to evaluate the predictive value of heat course > 7 days for infectious mononucleosis. Results:The majority of children with infectious mononucleosis had a heat course of 7 days (21.5%). There were no significant differences in clinical manifestations between the fever course > 7 days group and the fever course ≤ 7 days group (all P > 0.05). Neutrophil count, the proportion of monocytes, aspartate aminotransferase, and the proportion of suppressor T (Ts) cells in the fever course > 7 days group were (15.97 ± 7.60) × 10 9/L, 7.75 (4.93, 10.75)%, 53.00 (22.00, 91.50) U/L, 70.00 (57.00, 75.00)%, respectively, which were significantly higher than (15.21 ± 5.29) × 10 9/L, 5.40 (3.40, 9.60)%, 40.00 (30.00, 63.75) U/L, 63.50 (55.00,70.75)% in the fever course ≤ 7 days group ( t = -5.10, Z = -2.31, Z = -2.26, Z = -2.12, all P < 0.05). The proportion of helper T (Th) cells and the ratio of Th/Ts cells in the fever course > 7 days group were 13.00 (9.00, 17.00)% and 0.19 (0.12, 0.30)%, respectively, which were significantly lower than 16.00 (12.25, 20.75)%, 0.26 (0.18, 0.37)% in the fever course ≤ 7 days group ( Z = 2.44, 2.48, both P < 0.05). Multivariate logistic regression analysis showed that the increased proportion of Ts cells ( OR = 0.96, 95% CI 0.922-0.978, P < 0.05) was an influential factor of the prolonged course of fever. The area under the receiver operating characteristic curve of the proportion of Ts cells was 0.637. The cut-off value, sensitivity, and specificity were 67.50%, 61.3%, and 64.3%, respectively. Conclusion:Children with infectious mononucleosis with a longer heat course have more severe immune responses. The proportion of Ts cells > 67.5% can be used as a risk factor for the fever course > 7 days in children with infectious mononucleosis.

Objective:To analyze the risk factors associated with hemorrhagic complications at the puncture site after femoral artery access cerebrovascular interventions and construct a bleeding risk scale.Methods:Two hundred and fifteen patients who underwent femoral artery puncture interventions in the neurointerventional department ward of the First Affiliated Hospital of Zhengzhou University from April to October 2020 were selected for the study, including 60 cases in the complication group and 155 cases in the control group. The patients′ general data, interventional procedure-related data and laboratory tests were analyzed univariately and then incorporated into a binary multi-factor logistic regression analysis to determine independent risk factors, and a bleeding risk scale was constructed according to the regression model.Results:Compared with the control group, there was a statistically significant increase in the incidence of women, diabetes mellitus, use of glucose-lowering drugs, proportion of (anticoagulant/antiplatelet drugs) use and irritability in the complication group ( χ2 values were 4.94-15.81, all P<0.05); age, BMI, HbA1c, prothrombin time activity, and sheath size and operative time were higher than those of the control group, and prothrombin time and creatinine values were lower than those of the control group, with statistically significant differences ( t values of -6.25 to 2.80, respectively, all P<0.05). Multifactorial logistic regression analysis showed that gender ( OR=0.09, 95% CI 0.025-0.302), BMI ( OR=1.736, 95% CI 1.462-2.115), HbA1c ( OR=1.775, 95% CI 1.107-2.845), and use of anticoagulant/antiplatelet drugs ( OR= 0.082, 95% CI 0.015- 0.448) and time to surgery ( OR=1.031, 95% CI 1.012-1.052) were independent risk factors for bleeding complications. In the risk scale: the total score was -3 to 13, and risk existed for a score ≥5. The sensitivity of this scale was 83.3%, the specificity was 92.3%, and the area under the ROC curve was 0.878 ( P<0.001, 95% CI 0.818 to 0.938). Conclusions:Female, high BMI, high HbA1c, anticoagulant/antiplatelet drug use, and long procedure time can increase the risk of bleeding complications at the femoral artery puncture. The predictive model has good predictive performance and can be extended for use.

Objective:To summarize the clinical characteristics, causes of misdiagnosis and preventive measures of infectious mononucleosis (IM) in children, and to improve the ability of clinicians in early diagnosis of IM in children.Methods:The clinical data of 468 children with IM in Xi′an Children′s Hospital from January 2018 to December 2021 were retrospectively analyzed, including general situation, disease onset, diagnosis and misdiagnosis.Results:Among the 468 children, 33 cases were clinically diagnosed and 435 cases were a definitely diagnosed; 281 males (60.04%) and 187 females (39.96%); the incidence rate was highest in preschool children (43.80%, 205/468) and in autumn (33.12%, 155/468). The first symptoms were fever (52.99%, 248/468), eyelid edema (15.38%,72/468) and neck mass (14.96%, 70/468). The fever rate was 90.38% (423/468), and the median time of first fever appearance was on the first (first, second) day of disease course, and the median duration of fever was 6 (4, 8) d. The median time of first visit was on the third (first, fifth) day of disease course, and the time of diagnosis was on the seventh (fifth, ninth) day of disease course. Blood routine examination showed that the proportion of white blood cell count increased was 51.92% (243/468), the proportion of lymphocytes increased was 61.75% (289/468), and the proportion of abnormal lymphocytes increased (≥10%) in peripheral blood was 58.97% (276/468). The lymphocyte subsets of 364 children were detected, the rate of helper T lymphocytes (Th cells) decreased was 80.22% (292/364), the rate of suppressor T lymphocytes (Ts cells) increased was 99.45% (362/364), the value and decreased rate of Th cells/Ts cells were 0.24 (0.16, 0.40) and 100.00% (364/364), rate of B lymphocytes decreased was 93.96% (342/364), rates of natural killer cells decreased and increased were 35.16% (128/364) and 0.55% (2/364). The misdiagnosis rate was 55.13% (258/468), and the misdiagnosis time was on the fifth (fourth, seventh) day of disease course. Among the 258 misdiagnosed children, 105 cases (40.70%) were misdiagnosed as upper respiratory tract infection, 65 cases (25.19%) as acute suppurative tonsillitis, 27 cases (10.47%) as acute cervical lymphadenitis or neck mass.Conclusions:Due to the complex and diverse clinical manifestations of IM in children, it is easy to be misdiagnosed in the early stage of the disease. So, it is necessary for clinicians to master the clinical characteristics of IM in children, constantly improve the level of diagnosis and treatment, and reduce the misdiagnosis rate.

Objective:To investigate the changes of intestinal microecology in the early stage of sepsis rat model by 16S rDNA sequencing.Methods:Sixty male Sprague-Dawley (SD) rats were randomly divided into cecal ligation and puncture (CLP) group and sham operation group (Sham group), with 30 rats in each group. In the CLP group, sepsis rat model was reproduced by CLP method; the rats in the Sham group only underwent laparotomy without CLP. At 24 hours after the operation, the intestinal feces and serum samples of 8 rats in each group were collected. The survival rate of the rest rats was observed until the 7th day. The level of serum tumor necrosis factor-α (TNF-α) was detected by enzyme-linked immunosorbent assay (ELISA). Intestinal feces were sequenced by 16S rDNA sequencing technology. The operational taxonomic unit (OTU) data obtained after sequence comparison and clustering was used for α diversity and β diversity analysis, principal coordinate analysis and linear discriminant analysis effect size analysis (LEfSe) to observe the changes of intestinal microecology in early sepsis rats and excavate the marker flora.Results:At 24 hours after the reproduction of the model, the rats in the CLP group showed shortness of breath, scattered hair and other manifestations, and the level of serum TNF-α increased significantly as compared with that in the Sham group (ng/L: 43.95±9.05 vs. 11.08±3.27, P < 0.01). On the 7th day after modeling, the cumulative survival rate of the Sham group was 100%, while that of the CLP group was 31.82%. Diversity analysis showed that there was no significant difference in α diversity parameter between the Sham group and the CLP group (number of species: 520.00±52.15 vs. 492.25±86.61, Chao1 richness estimator: 707.25±65.69 vs. 668.93±96.50, Shannon index: 5.74±0.42 vs. 5.79±0.91, Simpson index: 0.93±0.03 vs. 0.94±0.05, all P > 0.05). However, the β diversity analysis showed that the difference between groups was greater than that within groups whether weighted according to OTU or not (abundance weighted matrix: R = 0.23, P = 0.04; abundance unweighted matrix: R = 0.32, P = 0.01). At the phylum level, the abundance of Proteobacteria and Candidatus_sacchari in the CLP group increased significantly as compared with the Sham group [18.100% (15.271%, 26.665%) vs. 6.974% (2.854%, 9.764%), 0.125% (0.027%, 0.159%)% vs. 0.018% (0.008%, 0.021%), both P < 0.05]. At the genus level, the abundance of opportunistic pathogen including Helicobacter, Ruthenium, Streptococcus, Clostridium ⅩⅧ in the CLP group was significantly higher than that in the Sham group [5.090% (1.812%, 6.598%) vs. 0.083% (0.034%, 0.198%), 0.244% (0.116%, 0.330%) vs. 0.016% (0.008%, 0.029%), 0.006% (0.003%, 0.010%) vs. 0.001% (0%, 0.003%), 0.094% (0.035%, 0.430%) vs. 0.007% (0.003%, 0.030%), all P < 0.05], and the abundance of probiotics such as Alloprevotella and Romboustia was significantly lower than that in the Sham group [7.345% (3.662%, 11.546%) vs. 22.504% (14.403%, 26.928%), 0.113% (0.047%, 0.196%) vs. 1.229% (0.809%, 2.29%), both P < 0.01]. LEfSe analysis showed that the probiotics belonging to Firmicutes were significantly enriched in the Sham group, and Romboustia was the most significantly enriched species. Opportunistic pathogens such as Helicobacter, Streptococcus and Clostridium ⅩⅧ were significantly enriched in the CLP group, Helicobacter_NGSU_ 2015 was the most significantly enriched species. Conclusion:In the early stage of sepsis, the intestinal microbiota structure of rats is significantly changed, which mainly shows that the abundance of Alloprevotella and other probiotics is significantly reduced, while that of Helicobacter and other opportunistic pathogens is significantly increased.

Objective:To clarify the pathogen types, genotypes and molecular biological characteristics of an outbreak in a high school in Yantai city in 2019, and to provide evidence for epidemic prevention and control.Methods:Eleven samples were collected from a high school in Yantai city in 2019. Quantitative PCR was used for primary type identification. RT-PCR and specific primers were used to amplify the target genes, and the sequences of norovirus were compared and analyzed for phylogenetic analysis.Results:The pathogen of this cluster outbreak was norovirus. Five GII-positive samples of norovirus were detected, 4 of which were GII.13 and 1 was GII.17. Sequence analysis of polymerase-capsid region showed that the amino acid sequence of this cluster outbreak was highly conserved.Conclusions:This outbreak is a cluster of diarrhea caused by GII.13 and GII.17 norovirus infection. The analysis of this outbreak is helpful to our general understanding of the evolution, genetic diversity and distribution of norovirus, and the surveillance of norovirus in the jurisdiction should be further strengthened.

Objective:To develop an artificial intelligence system for detecting dental plaque on permanent teeth and find the influenced factors.Methods:Photos of the labial or buccal surfaces of the permanent teeth were taken by using an intraoral camera (1 280×960 pixels; TPC Ligang, Shenzhen, China) before and after applying the plaque-disclosing agent (Cimedical, Japan) in 25 volunteers [12 males, 13 femals, aged (23±3) years] recruided in accordance with the inclusion criteria from the students of Peking University School of Stomatology from October 2018 to June 2019. A total of 549 groups of photos were captured and then divided into a training dataset containing 440 groups of photos and a test dataset including 109 groups of photos. The scopes of teeth and dental plaque on photos were labeled using LabelMe (Windows 3.2.1, MIT, U S A). A DeepLab based deep learning system was designed for the intelligent detection of dental plaque on permanent teeth. The mean intersection over union (MIoU) was employed to indicate the detection accuracy. Matlab (Windows R2017a, MathWorks, U S A) was used to extract the plaque edge line of 109 groups of photos and to calculate the number of pixels for the measurement of the complexity of the plaque edge line. The percentage of dental plaque area was calculated. Multivariate linear regression was used to explore whether tooth site, plaque percentage, number of plaque edge line pixels and lens light spot location would influence the detection accuracy, of which P<0.05 was considered statistically significant. Results:The MIoU of the permanent tooth model was 0.700±0.191 when 440 photos were used for training and 109 photos were used for testing. In the regression model of significance test ( P<0.05), the percentage of plaque and the number of pixels on the edge of plaque had significant influence on the accuracy of dental plaque detection. The standardized coefficient of the number of pixels of the plaque edge line is -0.289, and the standardized coefficient of the percentage of plaque is -0.551. Conclusions:In the present study, an artificial intelligence system was built to detect dental plaque area on tooth photos collected by family intraoral camera. The system showed the ability to detect the dental plaque of permanent teeth. The more complex the marginal line of dental plaque and higher the percentage of dental plaque are, the lower the accuracy of plaque recognition is.