Risk factors associated with severe manifestations of 2009 pandemic influenza A (H1N1) infection in China: a case-control study.

BACKGROUND: No studies on the risk factors of 2009 pandemic influenza A (H1N1) in China have been reported. We aimed to investigate the risk factors for severe manifestations of 2009 pandemic H1N1 influenza in China METHODS: A case-control study with 343 severe hospitalized patients and 343 randomly selected mild controls was conducted. The diagnosis was established by assessment of clinical symptoms and confirmed by the real-time reverse-transcriptase-polymerase chain reaction assay. Severe or mild patients were classified by uniform criteria issued by the Ministry of Health in China. RESULTS: The multivariable logistic regression analysis showed that the overweight or obese subjects admitted to hospital with H1N1 influenza were more likely to experience severe manifestations. The ORs were 3.70 (95% CI: 2.04-6.72) and 35.61 (95% CI: 7.96-159.21) respectively. Subjects at age less than 5 years or older than 60 years had an increased risk of severe manifestations (OR = 21.14, 95% CI: 7.79-57.33). We also observed increased risk among subjects with longer time interval from symptom onset to hospital admission (OR = 3.26, 95% CI: 2.08-5.11) or peasants (OR = 9.79, 95% CI: 5.11-18.78). Those with chronic disorders had increased risk of severe manifestations of H1N1 influenza. CONCLUSION: We provide evidence on the risk factors associated with severe manifestations of 2009 pandemic H1N1 influenza in a study of hospitalized subjects in China.

Characterization and Antioxidant Activities of Polysaccharide Isolated fromLinggui Zhugan Tang / 中国实验方剂学杂志

Objective:To characterize the structure of polysaccharide isolated from Linggui Zhugan Tang（LGZGT）,including monosaccharide composition and functional group detection, investigate the difference of the antioxidant activities of crude polysaccharide（CP） and pure polysaccharide（PP）, and provide the basis for the quality evaluation of LGZGT by in vitro bioassay. Method:The average molecular weight of CP was analyzed by high performance gel chromatography（HPGPC）. Gas chromatography-mass spectrometry（GC-MS） and fourier transform infrared（FT-IR） were employed to determine the structure of the polysaccharide. The antioxidant activities of CP and PP samples were evaluated on the basis of 1-diphenyl-2-picrylhydrazyl（DPPH） radical scavenging activity and OH radical scavenging activity. Result:The total polysaccharide was composed of single peaks, with a molecular weight of 3 689 Da. It was mainly composed of arabinose, mannose, glucose, galactose and fructose with a molar ratio of 6.85∶1.00∶109.21∶1.04∶21.82. Among them，glucose and fructose were the predominant components. In addition， IR study indicated the presence of pyranose and anomeric configurations in glycan structure, with two stereoisomers of glycosidic bond (α-glycosidic bond and β-glycosidic bond). It was found that the total polysaccharide had the ability of scavenging DPPH and hydroxyl radicals, and the activity of crude polysaccharide was better than that of refined polysaccharide. It was found in antioxidant research that the total polysaccharide had the ability of scavenging DPPH and hydroxyl radicals, and the activity of CP was better than that of PP. Furthermore, LC-Q-TOF-MS was used to qualitatively analyze the other components in CP, which indicated that it was related to the adsorption of pentacyclic triterpenoids in Glycyrrhiza uralensis. Conclusion:The polysaccharides and pentacyclic triterpenoids in LGZGT are the material basis for the antioxidative effect of LGZGT. The antioxidative activity determined by in vitro bioassay can be used as an evaluation index for the overall quality control of LGZGT.

[Etiological and molecular characteristics of pandemic influenza A (H1N1) virus during 2009-2010 in Shandong Province].

To isolate and identify the influenza virus in Shandong Province in 2009-2010 and analyze the genetic characteristics of hemagglutinin and neuraminidase gene, further study the variation of gene. A total of 17 126 nasopharyngeal swabs from fever patients were collected and detected by real time quantitative RT-PCR method. The results showed 4004 samples were pandemic influenza A (H1N1) virus positive, with an overall positive rate as 23.38%. The positive samples were incubated and cultured in MDCK cells. The HA and NA genes of isolated pandemic influenza A(H1N1) virus were sequenced, the homology analysis of the HA and NA genes showed an average of 96.9%-99.3% and 99.1%-99.6% sequence identity, respectively, compared with WHO-recommended vaccine strain. The genetic evolution and amino acid substitutions were performed with Mega 4.0 Software. Twenty one amino acids were changed in HA protein, of which 11 were located in the antigenic site; Sixteen amino acids were changed in NA protein, which didn't lead to the changes of enzyme sites. Furthermore, one glycosylation site of HA protein and NA protein were changed respectively. No H275Y mutation in NA protein was found. The results showed that the HA and NA genes of the epidemic strains were highly homologous, some mutations in the HA and NA proteins were found, the antigenic site and glycosylation site of some strains were changed during the epidemic process. All the strains were sensitive to oseltamivir.