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Sun F.,Xian University of Science and Technology | Sun F.,Institute of Environment and Health | Sun F.,Polytechnic University of Mozambique | Wu D.,Xian University of Science and Technology | And 4 more authors.
Food Control | Year: 2010

Klebsiella pneumoniae is an emerging opportunistic pathogen that causes severe morbidity and mortality among the newborn and immunocompromised persons. Infant formula has been associated with the K. pneumoniae-related outbreaks in a newborn intensive care unit. In this study, a SYBR Green real-time PCR assay was developed for the rapid identification of K. pneumoniae from infant formulas. 142-bp phoE gene was selected for specificity, and two K. pneumoniae strains and 15 non-K. pneumoniae strains were evaluated. All K. pneumoniae strains tested were phoE-positive to the real-time PCR detection and no cross-reactivity was observed with non-K. pneumoniae strains. Sensitivity of the detections is 1 CFU/25 g infant formulas. And the assays can be accomplished within two business days including pre-enrichment. The results indicate that the method is efficient and can be employed to detect specifically K. pneumoniae from infant formulas with considerable sensitivity. In this study, we also constructed reference standards for quantification of K. pneumoniae by real-time PCR. The values of the cycle threshold (Ct) were linearly correlated with the concentration of the reference standards, indicating that they can be used as quantitative detection of K. pneumoniae. This result is of special significance for applications of predicting the load of K. pneumoniae. © 2009 Elsevier Ltd. All rights reserved. Source

Sun F.-L.,Xian University of Science and Technology | Sun F.-L.,Polytechnic University of Mozambique | Jin M.,Institute of Environment and Health | Qiu Z.-G.,Institute of Environment and Health | And 3 more authors.
Academic Journal of Xi'an Jiaotong University | Year: 2010

Objective: To construct reference standards for detection and quantification of Klebsiella pneumoniae (K. pneumoniae) with SYBR Green I-based real-time PCR assay. Methods: Primers were designed based on the published sequence of the phoE gene of K. pneumoniae. The standard was prepared by cell culture, PCR and T-A clone methods, and was identified by colony PCR and DMA sequencing. Results: The standard curve showed a very good linear negative regression between threshold cycle (Ct) and Log starting quantity of copy number. The detection range was from 5.2 to 5.2 × 106 copies per reaction, and the detection limit was 6 copies per reaction. The coefficients of variance (CVs) of three parallel experiments were in the range of 0.05 %-0.91 %. Conclusion: The reference standards have high stability and reproducibility. They can be used in the quantitative detection of K. pneumoniae. Source

Xu X.-L.,Tianjin Medical University | Wang X.,Tianjin Medical University | Chen Z.-L.,Institute of Environment and Health | Jin M.,Institute of Environment and Health | And 3 more authors.
International Journal of Biological Sciences | Year: 2011

Objective: Grb2-associated binder 2 (Gab2), a member of the family of Gab scaffolding adaptors, transmits and amplifies the signals from receptor tyrosine kinases. A recent study demonstrated that Gab2 was over-expressed in breast cancers and metastatic melanomas, and Gab2 was an oncogenic protein. However, the roles of Gab2 in lung cancers are largely unknown. Method: In this study, to investigate whether Gab2 expression could be a characteristic of lung cancers, we analyzed the expression of Gab2 in 88 lung frozen tissue samples and 122 paraffin-embedded tissue specimens, using quantitative real-time-PCR, immunohistochemis-try and western blot. Results: We found that the positive expression rate of Gab2 in the tumor tissues, as detected by immunohistochemistry, 62.5% in squamous cell cancers, 51.35% in adenocarcinomas, and 75% in other types of lung cancers, was significantly higher than that (12%) in normal lung tissues. The mRNA expression detected by quantitative real-time-PCR and protein expression detected by western blotting in different groups were consistent with the immuno-histochemical results. Conclusion: Our data indicate that Gab2 is over-expressed in malignant lung tissues compared with that in normal lung tissues, and suggest that Gab2 expression may play a role in lung cancer development. © Ivyspring International Publisher. Source

Wang R.,Institute of Environment and Health | Zeng Q.,Institute of Environment and Health | Hou C.,Institute of Environment and Health | Cui W.,Institute of Environment and Health | And 5 more authors.
Chinese Journal of Endemiology | Year: 2014

Objective: To investigate the joint effects of excessive fluoride and iodine in drinking water on school-age children's dental fluorosis in the countryside of Tianjin. Methods: Based on the screening results of fluorine and iodine contents in drinking water in rural areas of Tianjin, three towns in Jinghai County and Wuqing District of Tianjin were selected as high fluoride and high iodine group, high fluoride and suitable iodine group, suitable fluoride and suitable iodine (control) group. Children aged 8-10 were selected as survey subjects. Morning urine was collected and dental fluorosis was examined. The concentration of urinary iodine was determined using arsenic cerium catalytic spectrophotometry (WS/T 107-2006), and urinary fluoride was detected using fluoride ion selective electrode method(WS/T 89-1996). Dean method was used to check the prevalence of dental fluorosis. Results: The urinary iodine median was 721.7, 788.3, 293.5 μg/L, respectively, and urinary fluorosis median was 2.48, 2.70, 1.59 mg/L, respectively. Urinary iodine and fluorosis were the highest in high fluoride and high iodine group, followed by high fluoride and suitable iodine group and control group(x2 = 35.10, 17.01, all P < 0.05). There was a significant difference of prevalence of dental fluorosis among the three groups(x2 = 15.39, P<0.05). The prevalence of dental fluorosis was the highest in high fluoride and suitable iodine group (85.3%, 29/34), followed by high fluoride and high iodine group(66.7%, 14/21) and control group(48.8%,21/43). Multiple Logistic regression analysis showed that the prevalence of dental fluorosis was adversely associated with fluorine concentration in drinking water[OR =7.273, 95% confidence limits(C/):1.676-31.562, x2 = 7.020, P < 0.05]. Conclusion: Drinking water with high fluoride and exposure of high fluoride combined with high iodine has a definite impact on children' s dental fluorosis. Source

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