Objective To investigate the prevalence, molecular mechanism and genetic characteristics of azithromycin-resistant Neisseria gonorrhoeae (N.gonorrhoeae) strains isolated in Shenzhen.Methods N.gonorrhoeae strains were collected in Shenzhen from 2011 to 2015.Agar dilution method and E-test were used to detect the minimum inhibitory concentrations (MIC) of these strains to azithromycin.All azithromycin-resistant (AZM-R) strains (MIC≥2 μg/ml) and some azithromycin-sensitive strains (MIC≤0.25 μg/ml) which were randomly selected as the control group were screened for mutations in 23S rRNA, mtrR and erm genes and genotyped by using N.gonorrhoeae multi-antigen sequence typing (NG-MAST).Results A total of 788 N.gonorrhoeae strains were collected, 148 (18.8%) of which were AZM-R strains (MIC≥1 μg/ml).Eighteen out of 21 high-level AZM-R (AZM-HLR) strains had A2143G mutations in the four copies of the 23S rRNA gene.Twelve out of 29 middle-level AZM-R (AZ-MLR) strains had missense mutations, among which C2611T mutations in the four copies of the 23S rRNA were detected in 10 strains.Incidence of G45D/Y105H mutation in AZM-HLR strains was higher than that in AZM-MLR (χ2=12.702, P=0.000) or AZ-S (χ2=4.462, P=0.035) strains according to the analysis of the promoter and coding region of mtrR gene.PCR analysis revealed that only one strain carried ermB gene (MIC=2 μg/ml).The 788 N.gonorrhoeae strains were typed into 81 sequence types (STs) by NG-MAST, most of which were represented by one strain only.STs of ST3356 and ST1866 that were identified in the AZ-R strains in the current study had been noted in a previous report of emerging AZM-R N.gonorrhoeae strains in Nanjing, Chongqing and Guangzhou.Neighbor-joining (NJ) phylogenetic tree showed that the resistant strains did not form a separate cluster.Conclusion Currently, it is not suitable to use azithromycin as a monotherapy for gonorrhea in Shenzhen.Mutations of A2059G and C2611T in 23S rRNA of N.gonorrhoeae were respectively responsible for high-level and middle-level resistance to azithromycin.Repeated emergence of ST1866 and ST3356 will help us monitor and analyze the epidemiological characteristics of N.gonorrhoeae strains resistant to azithromycin in Shenzhen.

Objective To analyze the relationship of penA, ponA, porB and mtrR gene mutations with the reduced sensitivity to ceftriaxone in N.gonorrhoeae isolates from Shenzhen city.Methods A total of 296 clinical isolates of N.gonorrhoeae were collected in Shenzhen city from 2009 to 2011.The agar dilution method was used to estimate the sensitivity of these N.gonorrhoeae to ceftriaxone.Totally, 53 strains with reduced sensitivity to ceftriaxone (minimum inhibitory concentration (MIC): 0.06-0.50 μg/ml) were identified, and 53 strains with high sensitivity to ceftriaxone were randomly selected from the remaining strains and served as the control group.PCR was performed to amplify the penA, ponA,porB and mtrR genes from the 106 isolates followed DNA sequencing.Results The mosaic structure of the penicillinbinding protein 2 (PBP2) gene (penA gene) was found in only one isolate with a ceftriaxone MIC of 0.125 0 μg/ml.Amino acid sequence analysis of the remaining 105 isolates yielded 16 different amino acid patterns.The MICs of ceftriaxone were relatively high (0.062 5 μg/ml) in N.gonorrhoeae strains harboring the amino acid patterns ⅩⅢ, ⅩⅧ or ⅩⅩⅩⅧ,but relatively low (0.008 0 μg/ml) in those harboring the amino acid pattern Ⅱ.No significant differences were observed in the frequency of mtrR, porB or ponA gene mutations between N.gonorrhoeae isolates with reduced sensitivity to ceftriaxone and those with high sensitivity (all P ＞ 0.05).Conclusions The mosaic structure of PBP2 may be not the primary reason for reduced sensitivity of Neisseria gonorrhoeae to ceftriaxone in Shenzhen, while different amino acid patterns produced by various mutations in amino acid residues at positions 500-580 in the non-mosaic PBP2, together with mtrR, porB and ponA mutations, may play more important roles in the reduced sensitivity.

OBJECTIVETo investigate the effect of short and long term exposure to SiO2 nanoparticles on microRNA expression level in human bronchial epithelial cells(16HBE cells).

METHODSThe 16HBE cells were exposed to 5, 10, 15, 20, 25, 30 and 40 μg/ml SiO2 nanoparticles for 24 h to detect the cell viability by using CCK-8 assay. The inhibition rate of proliferation activity and half inhibitory concentration (IC50) were calculated. The 16HBE cells were exposed to 10 μg/ml SiO2 nanoparticles for 10 and 30 generations, named P10 and P30, and the control P0 was set. The cells were treated with SiO2 nanoparticles at 0, 1/4 IC50, 1/2 IC50 and IC50 concentration and μm-SiO2 at IC50 concentration for 24 h, and the control serum-free culture medium was set. Agilent miRNAs microarray chip was used to screen differentially expressed miRNAs in P10, P30 and P0 groups. The expression level of miRNA was detected by reverse transcription fluorescence quantitative polymerase chain reaction (qRT-PCR).

RESULTSThe inhibition rate of proliferation activity of 5, 10, 15, 20, 25,30,40 μg/ml group were (-3.33 ± 3.80)%, (20.40 ± 11.73)%, (39.08 ± 5.53)%, (55.10 ± 5.78)%, (66.42 ± 9.60)%, (71.67 ± 7.34)%, (81.43 ± 5.37)%, respectively; F=129.11, P<0.001. The IC50 (95%CI) was 18.35 (15.82-20.72) μg/ml. The expression level of miRNA-494-3p in P0, P10 and P30 were 1.00, 0.45 ± 0.08, 0.28 ± 0.07, respectively; F=60.77, P<0.001. miRNA-19a-3p were 1.00, 2.27 ± 0.45, 1.06 ± 0.19, respectively; F=30.05, P<0.001. miRNA-148b-3p were 1.00, 1.78 ± 0.29, 0.88 ± 0.19, respectively; F=30.23, P<0.001. Compared to control group, the expression level of miRNA-494-3p in 5, 10, 20 μg/ml SiO2 nanoparticles groups and 20 μg/ml μm-SiO2 group were 0.99 ± 0.04, 1.38 ± 0.19, 2.13 ± 0.14, 0.81 ± 0.25, respectively; F=57.03, P<0.001. miRNA-19a-3p were 0.91 ± 0.03, 1.12 ± 0.03, 0.53 ± 0.01, 0.86 ± 0.01, respectively; F=408.78, P<0.001. miRNA-148b-3p were 0.95 ± 0.02, 1.22 ± 0.00, 0.54 ± 0.02, 1.15 ± 0.04 respectively; F=264.14, P<0.001.

CONCLUSIONShort and long term exposure to SiO2 nanoparticles can affect the expression level of miRNAs in 16HBE cells. The expressions of miRNA-494-3p after long and short period exposure are different.

Cells, Cultured ; Epithelial Cells ; drug effects ; metabolism ; Humans ; MicroRNAs ; metabolism ; Nanoparticles ; chemistry ; Oligonucleotide Array Sequence Analysis ; Silicon Dioxide ; chemistry

Objective To explore the effect of first-line anti-tuberculosis treatment on vitamin D level in patients with pulmonary tuberculosis,and to master the changes of vitamin D level in the course of treatment,so as to provide a scientific basis for tuberculosis and nutrition health education in Shenzhen.Methods A total of 100 patients diagnosed as smear-positive pulmonary tuberculosis and receiving initial treatment in 2016 were enrolled and all the patients were treated with the standardized short-course chemotherapy regimens.The blood samples were extracted before treatment and at the ends of intensive and continuation phase.The 25-hydroxyvitamin D [25-(OH) D] concentrations were determined by chemiluminescence (CLIA) at each time point.The change of 25-(OH) D concentrations during anti-tuberculosis treatment was analyzed and the differences of vitamin D levels between different time points were identified.Results 79 (79.0％),94 (94.0％) and 96 (96.0％) patients were found vitamin D deficiency before treatment and at the end of the intensive and continuation phases respectively,which showed an upward trend (x2=15.543,P＜0.001) and the 25-(OH)D concentrations were (15.74±6.54) ng/ml,(12.56±5.15) ng/ml,(11.51±4.28) ng/ml,respectively.During the whole course of treatment,the 25-(OH) D concentration decreased by 26.9％ or (4.23 ± 6.75) ng/ml (t =6.257,P＜0.001),wherein it decreased (3.18 ± 5.24) ng/ml in intensive phase (t =6.069,P＜ 0.001) and (1.05±4.86) ng/ml in continuation phase (t =2.154,P =0.034).The former had a greater decreased value (t=2.836,P=0.006).There were 77 (77.0％) and 55 (55.0％) patients with 25-(OH)D concentration reduction in intensive and continuation phases respectively (x2 =9.680,P =0.003),of which 41 patients (41.0％) continued to decline.Conclusion Once anti-tuberculosis treatment is conducted,the vitamin D level will decrease rapidly in the intensive phase and continue decreasing throughout the course of treatment,which leads to a general lack of vitamin D in patients with primary pulmonary tuberculosis.First-line anti-tuberculosis drugs may be the main cause for vitamin D level reduction.Therefore,it is necessary for clinicians to strengthen vitamin D health education for each patient throughout the treatment period,especially for those at high risk of vitamin D deficiency who should be recommended adjuvant vitamin D supplementation therapy.

Objective To evaluate the effect of micronutrient selenium on atopic dermatitis-like skin lesions in mice.Methods After 4-week feed with forages lacking selenium,40 BALB/c mice were randomly and equally divided into 4 groups:selenium deficiency group fed with forages containing 0.01 mg/kg selenium for 4 weeks,normal selenium supplementation group fed with forages containing 0.25 mg/kg selenium for 4 weeks,excessive selenium supplementation group fed with forages containing 3.00 mg/kg selenium for 4 weeks,and control group fed with forages containing 0.25 mg/kg selenium for 4 weeks.Then,atopic dermatitis-like skin lesions were induced by dinitrochlorobenzene (DNCB) in the mice in sensitized groups,including the selenium deficiency group,normal selenium supplementation group and excessive selenium supplementation group.During sensitization,the severity of dermatitis in mice was monitored.Three weeks after the sensitization,the total plasma IgE level and inflammatory cell count in whole blood were measured.Skin tissues from the back of mice were subjected to histopathological examination and the selenium level was detected.Statistical analysis was carried out by one-way analysis of variance for comparisons of IgE levels and cell counts among different groups,as well as by Pearson correlation analysis and linear regression analysis for analyzing the correlation of various indices with the selenium level.Results Six days after the sensitization,the dermatitis severity scores were significantly higher in the sensitized groups than in the control group (On day 6,8,11,13,15 and 18 after the sensitization,F =44.897,76.622,114.866,33.352,28.605 and 11.271 respectively,all P ＜ 0.01).On day 11 after the sensitization,the dermatitis severity score was significantly higher in the excessive selenium supplementation group than in the selenium deficiency group and normal selenium supplementation group (both P ＜ 0.05).Compared with the control group,obvious pathological changes of dermatitis were observed in the sensitized mice,but there was no significant difference in the number of inflammatory cells in skin lesions among the 3 sensitized groups (all P ＞ 0.05).The inflammatory cell count in whole blood and total plasma IgE level in the sensitized mice increased along with the increase of dietary selenium levels,and the excessive selenium supplementation group showed higher total plasma IgE level ([167.17 ±8.49] μg/L) compared with the selenium deficiency group ([124.78 ± 5.32] μg/L,t =3.919,P ＜ 0.05),normal selenium supplementation group ([132.61 ± 4.71] μg/L,t =3.222,P ＜ 0.05) and control group ([109.13 ± 0.79] μg/L,t =6.485,P ＜ 0.05).The selenium level in the skin tissues of sensitized mice was positively linearly correlated with the total plasma IgE level (r =0.579,P ＜ 0.001),whole-blood white blood cell count (r =0.414,P ＜ 0.05),neutrophil count (r =0.439,P ＜ 0.05),lymphocyte count (r =0.417,P ＜ 0.05)and eosinophil count (r =0.505,P ＜ 0.01).Conclusion Different dietary selenium levels showed different effects on the severity of dermatitis in mice,and more severe dermatitis occurred in the excessive selenium supplementation group.

OBJECTIVE: To explore the effects of nano-silicon dioxide( SiO_2) on the survival and poly( ADP-ribose)polymerase-1( PARP-1) expression in human bronchial epithelial cells( 16 HBE cells). METHODS: i) The 16 HBE cells were treated with nano-SiO_2 at concentrations ranging from 0 to 100 mg/L for 24. 0 hours,and CCK-8 assay was used to examine cell viability. ii) The 16 HBE cells were divided into 6 groups: solvent control group( equal volume solvent treatment),micro-SiO_2 control group( treated with 20 mg/L micro-SiO_2),5,10,and 20 mg/L nano-SiO_2 groups( treated with the corresponding final dose of nano-SiO_2),and curcumin group. The curcumin group was given pretreatment with curcumin at a final concentration of 10 μmol/L for 2. 0 hours followed by treatment with a final concentration of 20 mg/L of nano-SiO_2. Cells in each group were harvested at time points of 4. 0,12. 0 and 24. 0 hours after treatment. The relative expression of PARP-1 mRNA and protein in 16 HBE cells was detected by quantitative real-time polymerase chain reaction and Western blotting respectively. RESULTS: i) The survival of 16 HBE cells decreased with increasing nano-SiO_2 treatment dose,showing a dose-effect relationship( P < 0. 01). ii) The expression of PARP-1 mRNA and protein in 16 HBE cells were dose-dependently decreased after nano-SiO_2 stimulation at the 12. 0 and 24. 0 hours time points( P < 0. 01). The expression of PARP-1 mRNA and protein in 5,10,and 20 mg/L nano-SiO_2 groups decreased at the above mentioned time points( P < 0. 05),compared with the solvent control group at the same time points. The expression of PARP-1 mRNA and protein in 20 mg/L nano-SiO_2 group was lower than that in the micro-SiO_2 control group at the same 12. 0 and 24. 0 hours time point( P < 0. 05). The above two indexes of cells were higher in curcumin group than that of 20 mg/L nano-SiO_2 group at the 12. 0 hours time point( P < 0. 05). CONCLUSION: Nano-SiO_2 stimulation can lead to decrease survival of 16 HBE cells in a dose-dependent manner and down-regulation of PARP-1 expression may be one of the mechanisms of proliferation and inhibition of 16 HBE cells induced by nano-SiO_2. Curcumin has certain protective effect on nano-SiO_2-induced 16 HBE cell injury.

Objective: To determine the levels of vitamin D in patients with pulmonary tuberculosis in Shenzhen and identify the influencing factors of vitamin D levels and key groups of vitamin D deficiency, so as to provide a scientific basis for tuberculosis- and nutrition-related health education and promotion in Shenzhen. Methods: Patients with smear-positive pulmonary tuberculosis who were diagnosed in 2016 were selected as the research subjects. Their relevant information and blood samples were collected, and the sample pool was established according to the inclusion criteria. One hundred and twenty patients were selected based on simple random sampling, including 84 men (70.0%) and 36 women (30.0%). Blood 25-hydroxyvitamin D [25(OH)D] concentrations were measured using chemiluminescence technology. Vitamin D statuses in patients were statistically described, and vitamin D levels in patients with different characteristics were compared. Multivariate linear regression analysis was performed to identify important factors influencing vitamin D levels in patients. Results: Mean serum concentration of 25(OH)D in 120 patients was (40.2±16.0) nmol/L. There were 2 cases of vitamin D sufficiency (1.7%), 28 cases of vitamin D insufficiency (23.3%), and 90 cases of vitamin D deficiency (75.0%), of which 23 cases (19.2%) were of severe deficiency. 25(OH)D concentrations in patients with different lifestyles (indoors; indistinguishable indoors or outdoors; outdoors) were significantly different (35.3 nmol/L vs. 40.6 nmol/L vs. 49.5 nmol/L, F=8.274, P<0.001). Mean concentration of 25(OH)D in patients with sun exposure time of >30 min/d was higher compared to that in those with sun exposure time <30 min/d in the last month (46.4 nmol/L vs. 36.7 nmol/L, t=3.342, P=0.001). Multivariate linear regression analysis showed that the risk factors for 25(OH)D with statistical significance were Han ethnicity or not (β=-11.576, t=-1.991, P=0.049), housekeeping (including unemployment and retirement) or not (β=-6.136, t=-1.998, P=0.048), sun exposure time<30 min/d or none (β=-9.644, t=-2.829, P=0.006), body mass index (β=-2.056, t=-3.439, P=0.001) , and indoor degree of lifestyles (β=-4.419, t=-2.155, P=0.033). Conclusion Level of vitamin D is generally insufficient in patients with pulmonary tuberculosis in Shenzhen. It is necessary to strengthen health education related to vitamin D in patients with tuberculosis, especially in the high-risk population of vitamin D deficiency, such as in those with a lack of exposure to sunlight or high BMI.