Objective To investigate status and epidemiological characteristics of Mycoplasma pneumoniae (MP) infection in hospitalized children with respiratory tract infections from 2007 to 2013 in Suzhou region .Methods MP was determined by fluores‐cence quantitative polymerase chain reaction(PCR) in 34 332 sputum specimens of hospitalized children with respiratory tract infec‐tions in the Children′s Hospital Affiliated to Soochow University from 2007 to 2013 .Results The total detection rate of MP was 19 .01% in children with respiratory tract infections in Suzhou from 2007 to 2013 .Annual MP infection rates from 2007 to 2013 were 5 .45% ,6 .95% ,14 .06% ,18 .51% ,4 .85% ,25 .94% and 28 .68% respectively ,among which the infection rates of MP in 2012 and 2013 were significantly higher than that in other years (P<0 .05) .The infection rates of MP in female children(21 .01% )was higher than that in male children(17 .81% ) ,there was statistically significant difference(P<0 .05) .The infection rates of MP in children <1 years old ,1- <4 years old ,4- <7 years old and 7-14 years old were 8 .88% ,18 .05% ,35 .28% and 52 .39% respec‐tively ,and significant differences of infection rates of MP were observed among the age groups(P<0 .05) .The infection rates of MP in spring ,summer ,autumn and winter were 15 .96% ,28 .38% ,21 .71% and 11 .01% respectively ,and significant differences of in‐fection rates of MP were observed among the seasons(P<0 .05) .Conclusion MP is one of the most common pathogens responsible for respiratory tract infection in children ,which shows gender ,age and season differences in infection rate .Children aged 7 to 14 years old are susceptible to be infected by MP in summer and autumn ,especially in July and August ,so it is necessary to strengthen the prevention of MP infection .

Objective To explore the improvements of high-fat intake on lung injury induced by Paragonimus proliferus infection in rats, and to preliminarily explore the mechanisms underlying the role of cytochrome P450 4A1 (CYP 4A1) in the improve ments. Methods SD rats were randomly assigned into three groups, including the normal control group (n = 10), the infection and normal diet group (n = 12) and the infection and high-fat diet group (n = 12). Rats in the normal control group were fed with normal diet and without any other treatments, and animals in the infection and normal diet group were subcutaneously injected with 8 excysted metacercariae of P. proliferus via the abdominal wall, followed by feeding with normal diet, while rats in the infection and high-fat diet group were subcutaneously injected with 8 excysted metacercariae of P. proliferus via the abdominal wall, followed by feeding with high-fat diet. All rats were sacrificed 28 weeks post-infection, and serum samples and lung specimens were collected. Following hematoxylin-eosin (HE) staining of rat lung specimens, the rat lung injury was observed under an optical microscope, and alveolitis was evaluated using semi-quantitative scoring. Serum interleukin-1β (IL-1β) and tumor necrosis factor alpha (TNF-α) levels were measured using enzyme-linked immunosorbent assay (ELISA), and the cytochrome P450 4A1 (CYP 4A1) expression was quantified in rat lung specimens at transcriptional and translational levels using quantitative real-time PCR (qPCR) and Western blotting assays. Results Alveolar wall thickening, edema and inflammatory cell infiltration were alleviated 28 weeks post-infection with P. proliferus in rats in the infection and high-fat diet group relative to the infection and normal diet group, and no alveolar consolidation was seen in the infection and high-fat diet group. The semi-quantitative score of alveolitis was significantly higher in the infection and normal diet group [(2.200 ± 0.289) points] than in the normal control group [(0.300 ± 0.083) points] and the infection and high-fat diet group [(1.300 ± 0.475) points] (both P values < 0.05), and higher serum IL-1β [(151.586 ± 20.492)] pg/mL and TNF-α levels [(180.207 ± 23.379) pg/mL] were detected in the infection and normal diet group than in the normal control group [IL-1β: (103.226 ± 3.366) pg/mL; TNF-α: (144.807 ± 1.348) pg/mL] and the infection and high-fat diet group [IL-1β: (110.131 ± 12.946) pg/mL; TNF-α: (131.764 ± 27.831) pg/mL] (all P values < 0.05). In addition, lower CYP 4A1 mRNA (3.00 ± 0.81) and protein expression (0.40 ± 0.02) was quantified in lung specimens in the infection and normal diet group than in the normal control group [(5.03 ± 2.05) and (0.84 ± 0.14)] and the infection and high-fat diet group [(11.19 ± 3.51) and (0.68 ± 0.18)] (all P values < 0.05). Conclusion High-fat intake may alleviate lung injuries caused by P. proliferus infection in rats through up-regulating CYP 4A1 expression in lung tissues at both translational and transcriptional levels.