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Objective To study the epidemiology of mycoplasma pneumonia (MP) infection in children and its relationship to meteorological conditions in Guilin. Methods Total of 1 342 hospitalized children with respiratory tract infections from Janu-ary 2011 to December 2012 were recruited, and the serum levels of mycoplasma pneumoniae antibody Ig (MP-Ig) were measured. Meanwhile, monthly meteorological conditions were collected. The relationships between the MP-Ig detection rates and meteoro-logical conditions were analyzed by multiple linear regression analysis. Results The total detection rate of MP-Ig was 23.2%with positive rates as 5.51%, 28.99%, 37.31%and 44.97%for 0-1, 1-3, 3-6 and>6 year-old groups respectively (P<0.01). The positive rate of female was higher than that of male with signiifcant difference (30.08%vs 19.05%, P<0.01). The positive rate of spring, summer, autumn and winter were 18.89%, 17.39%, 23.83%and 33.05%individually (P<0.01). Negative correlation was found be-tween detection rate of MP-Ig and monthly mean air temperature (P=0.001). Conclusion MP is one of the commonest pathogens of respiratory tract infection in children and mostly seen in elder female children with a higher incidence in winter. The main me-teorological factor is the low temperature that affects MP prevalence.
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<p><b>OBJECTIVE</b>To isolate and characterize the side population cells (SP cells) in the lung adenocarcinomas cell line A549.</p><p><b>METHODS</b>The protein expression of ABCG2 in human lung adenocarcinoma cell line A549 was detected by immunohistochemistry. SP and NSP cells in the cell line A549 were isolated by FACS, and their differentiation was analysed. ABCG2 expression in the two cell subsets was detected by RT-PCR. The cell growth curves, cell division indexes, cell cycles, plate clone formation tests, migration and invasion assays, chemotherapeutic susceptibility tests, tests of the intracellular drug levels, and the tumor cell implantation experiments on nude mice were applied to study the biological properties of the two cell subsets. The expression of ABCG2 in the transplanted tumor in nude mice was detected by immunohistochemistry and RT-PCR.</p><p><b>RESULTS</b>The positive rate of ABCG2 expression in the A549 cells by immunohistochemistry was 2.13%. SP and NSP cells were isolated by FACS. The SP cells could produce both SP and NSP cells, while NSP cells only produced NSP cells. SP cells expressed ABCG2, but NSP cells did not. The proliferation and migration abilities of the two cell subsets were similar, but the invasion and tumorigenic ability of SP cells was significantly higher than that of NSP cells. The susceptibilities to DDP and its intracellular levels of the two cell subsets were similar, but the susceptibilities to 5-FU, VP16, NVB and GEM and their intracellular levels of NSP cells were significantly higher than those of the SP cells.</p><p><b>CONCLUSIONS</b>SP cells in the human lung adenocarcinomas cell line A549 is enriched with tumor stem cells. An effective way to get lung adenocarcinomas stem cells is to isolate SP cells by FACS.</p>