[Clinical analysis of 31 cases of 2019 novel coronavirus infection in children from six provinces (autonomous region) of northern China].

Objective: To analyze the epidemiological history, clinical manifestations, treatment and the short-term prognosis of 31 cases of 2019 novel coronavirus (2019-nCoV) infection in children from six provinces (autonomous region) in northern China. Methods: A retrospective analysis of the epidemiological history, clinical symptoms, signs, laboratory examinations, chest imaging, treatment and the short-term prognosis of 31 cases of 2019-nCoV was conducted. The patients were diagnosed between January 25th, 2020 and February 21st, 2020 in 21 hospitals in 17 cities of six provinces (autonomous region) of Shaanxi, Gansu, Ningxia, Hebei, Henan and Shandong. Results: The age of the 31 children with 2019-nCoV infection was 7 years and 1 month (6 months-17 years). Nine cases (29%) were imported cases. Other 21 cases (68%) had contact with confirmed infected adults. One case (3%) had contact with asymptomatic returnees from Wuhan. Among the 31 children, 28 patients (90%) were family cluster cases. The clinical types were asymptomatic type in 4 cases (13%), mild type in 13 cases (42%), and common type in 14 cases (45%). No severe or critical type existed. The most common symptom was fever (n=20, 65%), including 1 case of high fever, 9 cases of moderate fever, 10 cases of low fever. Fever lasted from 1 day to 9 days. The fever of fifteen cases lasted for ≤3 d, while in other 5 cases lasted >3 d. Other symptoms included cough (n=14, 45%), fatigue (n=3, 10%) and diarrhea (n=3, 10%). Pharyngalgia, runny nose, dizziness, headache and vomiting were rare. In the early stage, the total leukocytes count in peripheral blood decreased in 2 cases (6%), the lymphocytes count decreased in 2 cases (6%), and the platelet count increased in 2 cases (6%).Elevation of C-reactive protein (10%, 3/30), erythrocyte sedimentation rate (19%, 4/21), procalcitonin (4%,1/28), liver enzyme (22%, 6/27) and muscle enzyme (15%, 4/27) occurred in different proportions. Renal function and blood glucose were normal. There were abnormal chest CT changes in 14 cases, including 9 cases with patchy ground glass opacities and nodules, mostly located in the lower lobe of both lungs near the pleural area. After receiving supportive treatment, the viral nucleic acid turned negative in 25 cases within 7-23 days. Among them, 24 children (77%) recovered and were discharged from hospital. No death occurred. Conclusions: In this case series, 2019-nCoV infection in children from six provinces (autonomous region) in northern China are mainly caused by close family contact. Clinical types are asymptomatic, mild and common types. Clinical manifestations and laboratory examination results are nonspecific. Close contact history of epidemiology, nucleic acid detection and chest imaging are important bases for diagnosis of 2019-nCoV infection. After general treatment, the short-term prognosis is good.

[Inhibitory effect of quercetin on the biofilm formation of Streptococcus mutans].

OBJECTIVE: To observe the inhibitory effect of quercetin on the biofilm formation of Streptococcus mutans(Sm), to preliminarily reveal the possible underlying mechanisms, and to evaluate the cytotoxicity of quercetion to human dental pulp cells so as to provide the theoretical basis for the application of quercetin in oral biomaterials. METHODS: Quercetin storage solution was diluted to 0, 3.125, 6.25, 12.5, 25, 50, 100, 200, 400 and 800 mg/L, and added into Sm medium for 4 h and 24 h, crystal violet staining was used to evaluate the biofilm volume. In subsequent detections, three groups were set: control(0 mg/L), 200 mg/L quercetin and 400 mg/L quercetin. Confocal laser scanning microscopy was used to observe the morphology of the biofilm; qPCR for gtfB, gtfC, comD, comE, and luxS were assessed to preliminarily investigate the mechanisms. Finally, the methyl thiazolyl tetrazolium(MTT)test using human dental pulp cells was used to investigate cytotoxicity. RESULTS: Quercetin could significantly inhibit up to(86.16±0.45)% of the biofilm formation of Sm(Compared with the control group P=0.00)and effectively removed(43.04±0.53)% of the mature biofilm(Compared with the control group P=0.00). Confocal laser scanning microscopy photographs showed that after co-incubated for 24 h, the dense biofilm structures of the experimental group were destroyed by quercetin both at 200 mg/L and 400 mg/L. Quercetin suppressedover 50% of the expression of gtfB, gtfC, comD, comE(compared with the control group P<0.05)and promoted the expression of luxS up to 2.18 ± 0.24 and 2.84 ± 0.26 after 4 h and 24 h, respectively(compared with the control group P<0.05). Quercetin also exhibited acceptable compatibility for human dental pulp cells. CONCLUSIONS: Quercetin could effectively reduce the biofilm formation of Sm by inhibiting the expression of the related genes, and exhibited no cytotoxicity for human dental pulp cells. Quercetin has good potential to be applied in oral biological materials.

[The study of the nasal airway reactivity in specific nasal provocation test].

OBJECTIVE: To explore efficient evaluation method for specific nasal provocation test(SNPT) and to observe the pathogenic process and patho-physiological changes of allergic rhinitis. METHOD: 30 patients with perennial allergic rhinitis(patients group) and 14 normal adults(controls group) were challenged unilaterally with the Coca's solution and/or the solution for allergen extracts. The nasal resistance variations in all subjects were monitored with active anterior rhinomanometry and the nasal symptoms were observed. RESULT: The symptoms of nasal stiffness, sneezing and rhinorrhea appeared in most patients between 0.5 and 3 minutes after provocation. The ratio of continual sneezes above 5 in patients group(83.3%) was significantly higher than in controls group (21.4%) (P < 0.01). The increased ratio of total nasal resistance and unilaterally-challenged nasal resistance were significantly higher in patients group than in controls group (P < 0.05) and no difference between coca's solution in patients group and controls group. CONCLUSION: Positive SNPT was indicated if obvious nasal symptoms appeared and the unilaterally-challenged nasal resistance increased 100% as well as the total nasal resistance increased 40% after SNPT.