Epidemiological and clinical analysis of Mycoplasma pneumoniae infection in children with acute respiratory tract infection / 南方医科大学学报

<p><b>OBJECTIVE</b>To summarize the epidemiology and clinical characteristics of Mycoplasma pneumoniae (MP) infection in children with acute respiratory tract infection (ARI) in Guangzhou.</p><p><b>METHODS</b>MP was detected using an indirect immunofluorescent method in 2084 children with ARI. The relations between MP infection rate and the gender, age, season, site of infection and wheezing diseases were analyzed.</p><p><b>RESULTS</b>A total of 433 children (20.8%) were positive for MP, including 222 boys (19.8%) and 211 girls (21.9%) without significant difference in the infection rate between the genders (P>0.05). In 0- to 3-year-old group, 106 children were positive for MP (15.0%), while in 3- to 5-year-old group and 5- to 14-year-old group, 163 (25.2%) and 164 (22.5%) were positive, respectively, showing a significant difference in the infection rate between the 3 groups (P<0.05). The MP infection rate was 18.0% in January to March, 25.1% in April to June, 17.7% in July to September, and 20.5% in October to December, showing significant differences between the periods (P<0.05). No significant difference was found in the infection rate between children with acute upper respiratory tract infection (URI) and those with lower respiratory tract infection (LRI) (P>0.05). Among the children with LRI, those having wheezing disease had significantly higher MP positivity rate than those without wheezing.</p><p><b>CONCLUSION</b>MP is a common causative agent for ARI in children. MP infection is not related to gender and infection site, but to age and season. Children over 3 years old are vulnerable to MP infection. MP infection can be associated with wheezing in LRI.</p>

Depressant Effect of siRNA on the Expression and Replication of Hepatitis B Virus in HepG2.2.15 Cell / 实用儿科临床杂志

Objective To explore the siRNA as a new antiviral therapy,evaluate the inhibition effect of siRNA based on vector on the HBV of HepG2.2.15 cell,and observe the side effect and toxicity of siRNA vector on cells and the off-target effect of siRNA.Methods Three pairs of siRNA duplexes targeting HBV C gene were designed as double strands,and the duplex were annealed and ligated into the p-Silencer-Cmv 4.1-hygro vector.The ligation products were used to transform JM109 cells.The clones with shRNA were obtained,and the vectors were purified.After the initial identification of the vector with agarose gel and the size of the inserted sequence got examined by native polyacrylamide gel electrophoresis,furthermore the sequencing was further carried out.The recombinant plasmids were purified with ultrapure Midipreps DNA Purification System.Then HepG2.2.15 cells were transfected with the plasmid mixed with siPort XP-1.The expression of HBsAg and HBeAg were detected by immunofluorescence and Western blot,and the HBV RNA was investigated by RT-PCR.Furthermore the real-time quantitive PCR was carried out to detect the changes of HBV DNA.In order to evaluate the toxicity of the shRNA,MTT was used to examine the growth rate and curve of cells.The ELISA was performed to detect the changes of interferon-? (IFN-?).Results The Western blot showed that the HBsAg and HBeAg protein were suppressed with (81.15?0.69)%,(88.12?0.92)% respectively by vector p-C2 on the third day of post-transfection.It had the similar result indicated by immunofluorescence.And the RT-PCR showed that the specific siRNA targeting HBV C gene could markedly suppress the expression of HBV mRNA and the HBV C gene mRNA was inhibited with 96.9%.The real-time quantitive PCR showed that the specific functional siRNA could markedly suppress HBV DNA copy with two orders of magnitude,while the siRNA vector had no effect on the growth of cell showed by MTT detection.Compared with the non-transfected group and p-NC group,the IFN-? level was almost the same with siRNA p-C1,p-C2,p-C3 groups.Conclusions The siRNA based on the expression vector can suppress the expression and replication of HBV in HepG2.2.15 cell.The inhibition effect was specific and had a certain dependency on siRNA concentration.No toxicity effect was found in the study.And the drug resistance wouldn′t happen because the silence was based on the split of gene.