MicroRNA-370-3p inhibits cell proliferation and induces chronic myelogenous leukaemia cell apoptosis by suppressing PDLIM1/Wnt/β-catenin signaling

Growing evidence has suggested that microRNA-370-3p (miR-370-3p) is downregulated and acts as a suppressor in several cancers. However, the role of miR-370-3p in chronic myeloid leukemia (CML) remains unknown. Here, the expression level and molecular mechanism of miR-370-3p in CML were investigated. Firstly, the expression of miR-370-3p has markedly decreased in the peripheral blood mononuclear cells (PBMCs) of patients with CML and in cell lines. Moreover, miR-370-3p in CML cells upregulated and downregulated proliferation and apoptosis, respectively. Notably, miR-370-3p directly targeted the 3'-untranslated region of PDZ and LIM domain protein 1 (PDLIM1). A negative correlation was observed between the levels of miR-370-3p and PDLIM1 in the PBMCs of patients with CML and healthy volunteers. PDLIM1 was shown to have an oncogenic role in CML cells by promoting proliferation and suppressing apoptosis. Finally, the miR-370-3p-PDLIM1-Wnt/β-catenin signaling axis was indicated to play an important role in CML progression.

Antimicrobial susceptibility of Streptococcus sp. to quinupristin-dalfopristin in China

This study aimed to determine the in vitro activity of quinupristin-alfopristin against Streptococcus sp. isolated in China. This agent is not yet available for clinical use, but it has been tested against a high proportion of resistant Staphylococcus aureus strains. A total of 156 streptococcal isolates, which were recovered from various geographic areas and diseases, were tested using the Etest (AB Biodisk, Solna, Sweden). Quinupristin-alfopristin showed excellent activity against all of the tested streptococci isolates. These results provide useful data for the clinical use of quinupristin-alfopristin in China.

Molecular epidemiological characteristics of Streptococcus pyogenes strains involved in an outbreak of scarlet fever in China, 2011

OBJECTIVE

To investigate molecular characterization of streptococcus pyogenes isolates involved in an outbreak of scarlet fever in China in 2011.

METHODS

Seventy-four Streptococcal pyogenes involved in an outbreak of scarlet fever were isolated from pediatric patients in the areas with high incidence in China from May to August of 2011. Emm genotyping, pulsed-field gel electrophoresis (PFGE), superantigen (SAg) genes and antimicrobial susceptibility profiling were analyzed for these isolates.

RESULTS

A total of 4 different emm types were identified. Emm12 was the most prevalent type which contained four predominating PFGE patterns corresponding to four different virulence and superantigen profiles. Emm12 (79.7%) and emm1 (14.9%) accounted for approximately 94% of all the isolates. The speA gene was all negative in emm12 isolates and positive in emm1 isolates. All strains were resistant to erythromycin, and 89.4% of them were resistant to erythromycin, tracycline, and clindamycin simultaneously.

CONCLUSION

Several highly diversified clones with a high macrolide resistance rate comprise a predominant proportion of circulating strains, though no new emm type was found in this outbreak. The data provide a baseline for further surveillance of scarlet fever, which may contribute to the explanation of the outbreak and development of a GAS vaccine in China.

Safety observation study on haemophilus influenza type B conjugate vaccines injected at different sites in Chinese infants

In the present study, the safety of Haemophilus influenza type b conjugate vaccines inoculated in the upper arm deltoid and vastus lateralis muscle was evaluated. 680 infants aged 2-5 months and 6-12 months were selected to be the research subjects in whom the Hib conjugate vaccines were inoculated by injection in the upper arm deltoid and vastus lateralis muscle, respectively. The safety analysis indicated that there were no statistic differences in the incidence rates of adverse reactions when the Hib conjugate vaccines were inoculated at different sites. So we concluded that the safety of inoculation injection of Hib conjugate vaccines in vastus lateralis muscle was the same as that inoculated in the upper arm deltoid.

[The mechanism of macrophage apoptosis induced by lipopolysaccharide in mice]

Apoptosis is a major form of cell death, characterized morphologically by chromatin condensation and biochemically by endonuclease cleavage of DNA into oligonucleosomal fragments. We investigated apoptosis mechanism of peritoneal macrophage(M phi) induced by peritoneal injection of lipopolysaccharide(LPS) in mice. The results showed that: LPS induced the apoptosis of peritoneal M phi and concomitant decrease of phagocytosis(vs control group, P < 0.01), the concentration of NO2-/No3- in the peritoneal lavage fluid significantly increased after LPS injection; AG(inhibitor of iNOS) and PDTC(inhibitor of reactive oxygen species) prevented the apoptosis of M phi and reduced the concentration of NO2-/NO3- in the peritoneal lavage fluid. In vitro experiment, we found that AG and PDTC inhibited the apoptosis of M phi induced by IFN(100 U.ml-1) + LPS (10 micrograms.ml-1) by using DNA gel electrophoresis analysis. These evidences support that NO and active oxygen species may be involved in the apoptosis process of peritoneal M phi induced by LPS in mice.

Heat shock pretreatment prevents hydrogen peroxide injury of pulmonary endothelial cells and macrophages in culture

The purpose of the present study was to determine whether heat shock pretreatment would protect pulmonary endothelial cells and alveolar macrophages against hydrogen peroxide (H2O2)-induced injury. The bovine pulmonary artery endothelial cells (BPAECs) heat-shocked (42 degrees C for 2 h) prior to exposure to H2O2 (1 mmol/L for 45 min) showed significant decrease in H2O2-mediated increment of release of lactate dehydrogenase and production of thiobarbituric acid-reactive substances, and obvious alleviation in H2O2-induced decrease in activities of catalase and superoxide dismutase. Heat-shocked (42 degrees C for 2 h) rat pulmonary alveolar macrophages (PAMs) also obtained acquired resistance to injury by subsequent exposure of 1, 2, or 3 mmol/L H2O2 for 45 min. Simultaneously with this acquired oxidative resistance, Northern blot analysis showed that heat-shocked BPAECs and PAMs, contained an increased level of mRNA coding for the inducible form of heat shock protein 70 (HSP70), and Western blot analysis indicated that there were increased expression of HSP70. Inhibition of protein synthesis by cycloheximide (25 micrograms/mL) and inhibition of RNA synthesis by actinomycin D (5 micrograms/mL) prevented the cytoprotection against H2O2. These results are consistent with the hypothesis that heat shock pretreatment would protect pulmonary endothelial cells and alveolar macrophages against H2O2-induced injury, and possibly that HSPs play a role in this cytoprotection.

[A study on the relationship between drinking water with high arsenic content and incidence of malignant tumour in Heihe Village, western part of Huhehot, Inner Mongolia]

Since 1991, it has been repeatedly reported that endemic arsenism was noticed in the large areas in the middle and west parts of Inne Mongolian Autonomous Region. Heihe village is located in a geological area with rich natural arsenic. The inhabitants of the village have drunk the water with high arsenic content for a long time and many people have died of malignant tumours. A historical prospective method has been used in the study. The research has been carried out chronologically on the statistical relationship between drinking water with high arsenic content consumed by local inhabitants for 22 years and the mortality of malignant tumours. This study has confirmed that the accumulated mortality rate and the average mortality rate of Heihe villagers who had drunk the water with high arsenic content for a number of total 22 years (from January 1971 to January 1993) were 13 590/10(5) person-year and 642.01/10(5) person-year. In terms of the portion among all malignant tumour deaths, cancer for the lung takes the lead, followed by liver cancer and then bladder cancer. The risk of death of malignant tumours in the villagers who drink water with high arsenic content was 9.38 times to the risk in the inhabitants who do not drink water with high arsenic content.

Hemorrhagic fever with renal syndrome. Separation of human peripheral blood T and B cells and detection of viral antigen

In this study, total blood lymphocytes were prepared from patients with hemorrhagic fever with renal syndrome (HFRS) by a density gradient on Ficoll-Hypaque. T and B cells were then purified by passing the total lymphocytes over a nylon wool column. The purities of total lymphocytes, T cells and B cells were 97.8 +/- 2.3%, 91.6 +/- 4.5% and 74.2 +/- 12.1%, respectively. Also, after modification of cell fixation and smear drying, the number of cells were increased and the time needed for slide preparation was shortened. Detection of viral antigen by immunofluorescence assay using monoclonal antibodies to Hantavirus (HTNV) showed that the total lymphocytes. T cells and B cells were infected by HTNV during the early stages of HFRS and no specific fluorescence was seen in the cells from the late diuretic phase to convalescent phase. The results suggest that virus replication in blood lymphocytes may partly contribute in the early stages to the impairment of cell immune response and in vivo spread of HTNV to its target sites.

Relevance of N-nitrosamines to esophageal cancer in China

Studies on the relevance of the N-nitrosamines to esophageal cancer in China are reviewed. Esophageal cancer is a complex and multifactorial problem. Although a causal association between nitrosamines exposure and esophageal cancer in China has not yet been rigorously established, exposure of Lin-Xian subjects to nitrosamines either directly or as a result of their in vivo formation has been detected in our study. Several N-nitrosamines (NDMA, NDEA, NMBzA, NPyr, NPip, and NSAR) in gastric juice collected from Lin-Xian inhabitants have been detected. A correlation was found between the lesions of esophageal epithelium and the amount of nitrosamines present. In addition, the amounts of N-nitrosamino acids (N-nitrosoproline, N-nitrosothiazolidine 4-carboxylic acid, NSAR, and nitrates) excreted in 24-hr urine of subjects in Lin-Xian were significantly higher than those in Fan-Xian, indicating a higher exposure to N-nitroso compound and their precursors of the inhabitants in the high-risk area. The effect of nitrosamines on human esophagus has been investigated at the cellular levels. The amounts of O6-MedG in DNA of esophageal or stomach mucosa of patients from Lin-Xian were higher than that from Europe (Lyon and Essen). The presence of O6-MedG in the human fetal esophagus cultured with NMBzA was also detected. These findings indicate that the elevated levels of O6-MedG in esophageal DNA could be the result of a recent exposure to N-nitroso compounds or a genetically determined reduced cellular capacity for repair of O6-MedG from DNA. The hyperplasia was induced in the esophagus of human fetus that cultured with NMBzA for 2 weeks to 2 months. The intervention studies of esophageal cancer in Lin-Xian have been pursued. Intake of moderate doses of ascorbic acids by Lin-Xian subjects effectively reduced the urinary levels of N-nitrosamino acids to those found in un-dosed subjects in the low-risk area. If N-nitroso compounds are formed in vivo and are among the causative factors of esophageal cancer in Lin-Xian, ascorbic acid appears to be effective in lowering the body burden of these carcinogenic compounds. Thus, the plan of chemoprevention is carried out in Lin-Xian.