Epidemiology and mechanism of drug resistance of Mycoplasma pneumoniae in Beijing, China: A multicenter study.

Mycoplasma pneumoniae (M. pneumoniae) is one of the most common causes of community-acquired respiratory tract infections (RTIs). We aimed to investigate the prevalence of M. pneumoniae infection, antibiotic resistance and genetic diversity of M. pneumoniae isolates across multiple centers in Beijing, China. P1 protein was detected by Nested PCR to analyze the occurrence of M. pneumoniae in pediatric patients with RTI. M. pneumoniae isolates were cultured and analyzed by Nested-PCR to determine their genotypes. Broth microdilution method was used to determine the minimum inhibitory concentration (MIC) of antibiotics. Out of 822 children with RTI admitted to 11 hospitals in Beijing, 341 (41.48%) were positive for M. pneumoniae by Nested PCR and 236 (69.21%) samples had mutations in 23S rRNA domain V. The highest proportion of M. pneumoniae positive samples was observed in school-age children (118/190; 62.11%) and in pediatric patients with pneumonia (220/389; 56.56%). Out of 341 M. pneumoniae positive samples, 99 (12.04%) isolates were successfully cultured and the MIC values were determined for 65 M. pneumoniae strains. Out of these, 57 (87.69%) strains were resistant to macrolides, and all 65 strains were sensitive to tetracyclines or quinolones. M. pneumoniae P1 type I and P1 type II strains were found in 57/65 (87.69%) and 8/65 (12.31%) of cultured isolates, respectively. Overall, we demonstrated a high prevalence of M. pneumoniae infection and high macrolide resistance of M. pneumoniae strains in Beijing. School-age children were more susceptible to M. pneumoniae, particularly the children with pneumonia. Thus, establishment of a systematic surveillance program to fully understand the epidemiology of M. pneumoniae is critical for the standardized use of antibiotics in China.

Genistein ameliorated endothelial nitric oxidase synthase uncoupling by stimulating sirtuin-1 pathway in ox-LDL-injured HUVECs.

Endothelial nitric oxidase synthase (eNOS) uncoupling plays a causal role in endothelial dysfunction in atherosclerosis. Genistein consumption has been associated with the prevention of atherosclerosis. However, the effect of genistein on eNOS uncoupling has not been reported. A model of oxidized low-density lipoprotein (ox-LDL)-induced injury on human umbilical vein endothelial cells (HUVECs) was established to evaluate the effect of genistein on eNOS uncoupling. We investigated the effect of genistein on NADPH oxidase-dependent superoxide production, NOX4 expression, BH4 synthesis and oxidation, the expression of GTP cyclohydrolase 1 (GCH1) and dihydrofolate reductase (DHFR). The results showed that genistein decreased superoxide production and NOX4 expression, enhanced the ratio of BH4/BH2, augmented the expressions of GCH1 and DHFR. Accompanied with genistein ameliorating eNOS uncoupling, genistein elevated the expression of sirtuin-1; furthermore, the effects of genistein on eNOS uncoupling were blunted with sirtuin-1 siRNA. The present study indicated that genistein ameliorated eNOS uncoupling was concerned with sirtuin-1 pathway in ox-LDL-injured HUVECs.

Genistein inhibits ox-LDL-induced VCAM-1, ICAM-1 and MCP-1 expression of HUVECs through heme oxygenase-1.

BACKGROUND AND AIMS: Genistein, a principal component of soybean isoflavones, plays an important role in the prevention of atherosclerosis. However, the detailed mechanisms have not been fully investigated. The aims of this study were to evaluate the anti-atherosclerotic effect and investigate potential pharmacological mechanism of genistein. METHODS: A model of oxidized low-density lipoprotein (ox-LDL)-induced injury in on human umbilical vein endothelial cells (HUVECs) was established to evaluate the protective role of genistein. Macrophage/monocyte chemoattractant protein-1 (MCP-1), vascular cellular adhesion molecule-1 (VCAM-1) and intracellular adhesion molecule-1 (ICAM-1) secretion and their messenger RNA transcription were observed via enzyme-linked immunosorbent assay (ELISA) and reverse transcriptase PCR (RT-PCR). Meanwhile, the study investigated the role of Nrf2/HO-1 pathway during the process. RESULTS: Pretreatment with genistein markedly reduced ox-LDL-induced MCP-1, VCAM-1 and ICAM-1 secretion and mRNA transcription, which was further decreased by the inducer of HO and reversed by the inhibitor of HO; additionally, the effects were accompanied with upregulating HO-1 mRNA and protein expression and markedly abolished with Nrf2 siRNA. CONCLUSIONS: Anti-inflammatory effect of genistein on endothelial cells may be associated with the activation of Nrf2/HO-1 pathway.

Allele-specific real-time PCR testing for minor HIV-1 drug resistance mutations: assay preparation and application to reveal dynamic of mutations in vivo.

BACKGROUND: It is very important for the clinical management to test for minor HIV-1 resistance mutations accurately and sensitively. The conventional genotypic assays of HIV drug resistance detection based on sequencing can only discriminate the mutations which present in more than 20% - 30%. The aim of this study was to evaluate allele-specific real-time PCR (ASPCR) to detect the resistance-related mutations located at positions 103, 184 and 215. METHODS: We developed the allele-specific PCR assay, using the most common drug resistance mutations in Chinese AIDS patients, K103N, M184V/I, T215F/Y as a model system. The standards were constructed by cloning the wild-type and mutant DNA fragments into the T-vector. We designed specific primers to discriminate mutant templates in the real-time PCR using SYBR green as a fluorescence reporter. And then we evaluated the ASPCR assay and tested 140 clinical samples using this method. RESULTS: The sensitivities of ASPCR assay were 0.04% for K103N, 0.30% for M184I, 0.40% for M184V, 0.03% for T215F and 0.02% for T215Y. The intra-assay and inter-assay coefficients of variation were less than 0.42. One hundred and forty plasma samples were tested by ASPCR and dynamic resistance curves of ten patients were obtained. CONCLUSIONS: Drug resistance emerged half a year after the start of antiretroviral therapy. The mutation of T215Y emerged 1 to 1.5 years after starting treatment and then increased rapidly. The ASPCR assay we developed was a sensitive, accurate and rapid method to detect the minor HIV-1 variants and it can provide earlier and more drug-resistance information for HIV research and AIDS antiretroviral therapy.

[Ultrastructural study on pharyngeal armature of seven species of sandflies in china by scanning electron microscopy].

OBJECTIVE: To observe the ultrastructure of pharyngeal armature of 7 species of sandflies in China. METHODS: The pharyngeal armature of various sandflies were studied by scanning electron microscopy. RESULTS: The pharyngeal armature of sandfly consisted of pointed-teeth with various shape, number and arrangement among different species. CONCLUSION: Such differences may provide the morphological proof for identification of species.