The phenotypic and genotypic characterization of Enterobacter sakazakii strains from infant formula milk

Enterobacter sakazakii is an emerging foodborne pathogen associated with severe diseases in neonates. Infant formula milk (IFM) has been identified as one of the major contaminated sources and a transmission vehicle. To determine the phenotypic and genotypic characterization of this pathogen, 22 E. sakazakii strains isolated from IFM by an FDA-recommended method and PCR on the alpha-glucosidase gene were subtyped by random amplified polymorphic DNA (RAPD)-PCR, enterobacterial repetitive intergenic consensus (ERIC)-PCR, and antibiotic resistance patterns. At a similarity threshold of 80%, 16 ERIC-PCR fingerprint types were identified with a discriminatory power (D) of 0.933, and 18 RAPD-PCR types were identified with D of 0.973. Resistance to 9 antibiotics tested by disk diffusion assay revealed 6 antibiotic resistance patterns with D of 0.749. The comparison of characterization indicated that RAPD-PCR and ERIC-PCR have high discriminatory power showing genetic diversity of E. sakazakii isolates, and ERIC-PCR patterns showed a closer correlation than RAPD-PCR patterns to phenotypic characterization and the brands of IFM. Overall, the ERIC-PCR typing method could be used for tracing sources of E. sakazakii isolates in the food chain.

Urinary cadmium, osteopenia, and osteoporosis in the US population

SUMMARY

The association between cadmium and osteoporosis in a multiethnic population is unclear. We found that urinary cadmium is consistently associated with osteopenia and osteoporosis in the Third National Health and Nutrition Examination Survey, regardless of age, sex, race, and smoking status. Cadmium exposure may be an independent risk factor for osteoporosis.

INTRODUCTION

Our purpose was to test whether cadmium exposure is associated with a higher prevalence of osteopenia and osteoporosis in the general US population and selected subgroups.

METHODS

We used multinomial logistic regression to analyze data on 10,978 subjects (aged 30-90) from the Third National Health and Nutrition Examination Survey. We studied the association of urinary cadmium levels (adjusted for urinary creatinine) and the prevalence of osteopenia and osteoporosis as defined by the World Health Organization.

RESULTS

After adjustment for age, sex, ethnicity, body mass index, calcium intake, and physical inactivity, odds ratios (ORs) for osteopenia and osteoporosis increased dose dependently with two urinary cadmium levels (in micrograms of urinary cadmium per grams of urinary creatinine: level I, 1.00-1.99 mcg/g; level II, > or =2.00 mcg/g). Osteopenia results were as follows: level I OR, 1.49 (95% confidence interval [CI], 1.24-1.80); level II OR, 2.05 (95% CI, 1.52-2.78). Osteoporosis results were as follows: level I OR, 1.78 (95% CI, 1.26-2.52); level II OR, 3.80 (95% CI, 2.36-6.14). The association was consistent in all age, sex, race, and smoking status subgroups.

CONCLUSIONS

Cadmium exposure may be a potential risk factor for osteopenia and osteoporosis in the general US population.

High-resolution melting analysis of PCDH10 methylation levels in gastric, colorectal and pancreatic cancers

Protocadherins are celladhesion molecules with 6 or 7 cadherin motifs in their extracellular domain and various cyotoplasmic domains. PCDH10 was characterized a novel tumor suppressive gene in and was epigenetically silenced in multiple haematologic malignancies as well as some solid tumors such as gastric cancer, nasopharyngeal carcinoma and esophageal carcinoma. High-resolution melting (HRM) analysis has been used as a novel tool for analysis of promoter methylation. In our study, we used HRM analysis to detect the methylation levels of PCDH10 gene in 100 gastric cancers, 100 colorectal cancers, 70 pancreatic cancers and equal number of adjacent normal tissues. The frequency of PCDH10 methylation in all three types of cancers was significantly higher than that in normal tissues. Consistent with previous reports, expression levels of PCDH10 were inversely correlated with methylation levels. But we didn't find significant association between PCDH10 methylation status and TNM staging in all three types of cancers. In summary, application of HRM analysis to large amount of clinical samples proves to be a fast and high-throughput way to investigate the epigenetic status of PCDH10. And this is the first study to evaluate the prevalence of PCDH10 methylation based on large amount of tumor samples, showing that epigenetic regulation of PCDH10 was associated with carcinogenesis.

Distribution and fate of polybrominated diphenyl ethers in indoor environments of elementary schools

Polybrominated diphenyl ethers (PBDEs) are considered harmful to human health because of their toxicities and persistence in environments. In the current study, the distribution and fate of PBDEs in classrooms and computer rooms in 17 elementary schools in South Korea have been described. Eight congeners (brominated diphenyl ether-28, -47, -99, -100, -153, -154, -183, and -209) in air, floor dust, and product surface dust were measured. While Sigma(8)PBDEs in the air in classrooms showed considerable variations (0.659-1600 pg/m(3), arithmetic mean +/- s.d.: 377 +/- 441 pg/m(3)), those in computer rooms were somewhat similar (134-220 pg/m(3), arithmetic mean +/- s.d.: 169 +/- 40 pg/m(3)). Sigma(8)PBDEs in floor dust varied over a wide range, from 453 to 45,700 ng/g, for all rooms. Based on congener patterns, two groups were created--CL-1 that is dominated by high-brominated congeners and CL-2 primarily comprising low-brominated congeners--for both air and floor dust of classrooms. Surface dust had low concentrations, ranged from ND to 181, from ND to 128, and from ND to 256 pg/cm(2) for desk/chair sets, lockers, and playing tools, respectively. Pearson correlation coefficients were calculated individually for air, floor dust, and surface dust. The results indicate that both surface dust and floor dust may act as a secondary source of PBDEs in indoor environments after emission from facilities.

PRACTICAL IMPLICATIONS

Children have been estimated to have a higher potential exposure to PBDEs than adults. Since children spend most of their day time at school, PBDE distributions in school environments should be a matter of great concern.

Significance of mutation in the D-loop region in cervical cancer

AIM

To investigate the mutation in the D-loop region of mitochondrial DNA in cervical cancer and its influence on the changes of reactive oxygen species (ROS) and cell cycle.

METHODS

The D-loop region was amplified by PCR and sequenced. Reactive oxygen species and cell cycle were detected by flow cytometry in 40 specimens from cervical cancer and adjacent normal tissues. According to the sequence results, gastric cancer tissue was divided into mutation group and control group. Reactive oxygen species, apoptosis and proliferation in the two groups were compared.

RESULTS

Among the 40 cervical cancer specimens, 21 mutations were identified in 12 patients, the mutation rate being 30%. There were four microsatellite instabilities in the mutations. No mutation was found in the adjacent tissues. Reactive oxygen species, apoptosis and proliferation in the mutation group were all significantly higher than those in the control group.

CONCLUSION

Mutation in the D-loop region plays a role in the genesis and development of cervical cancer.

Deficiency in myosin light-chain phosphorylation causes cytokinesis failure and multipolarity in cancer cells

Cancer cells often have unstable genomes and increased centrosome and chromosome numbers, which are an important part of malignant transformation in the most recent model of tumorigenesis. However, very little is known about divisional failures in cancer cells that may lead to chromosomal and centrosomal amplifications. In this study, we show that cancer cells often failed at cytokinesis because of decreased phosphorylation of the myosin regulatory light chain (MLC), a key regulatory component of cortical contraction during division. Reduced MLC phosphorylation was associated with high expression of myosin phosphatase and/or reduced myosin light-chain kinase levels. Furthermore, expression of phosphomimetic MLC largely prevented cytokinesis failure in the tested cancer cells. When myosin light-chain phosphorylation was restored to normal levels by phosphatase knockdown, multinucleation and multipolar mitosis were markedly reduced, resulting in enhanced genome stabilization. Furthermore, both overexpression of myosin phosphatase or inhibition of the myosin light-chain kinase in nonmalignant cells could recapitulate some of the mitotic defects of cancer cells, including multinucleation and multipolar spindles, indicating that these changes are sufficient to reproduce the cytokinesis failures we see in cancer cells. These results for the first time define the molecular defects leading to divisional failure in cancer cells.

Yields from blood cultures of patients with suspected paratyphoid fever A

The yield and speed of detection of Salmonella enterica serotype Paratyphi A from the blood of patients with suspected paratyphoid fever A in 13 500 paired aerobic and anaerobic bottles (AEB, ANB) that were each filled with 5 ml of blood by the BacT/ALERT 3D system were compared, and the blood bacterial counts of 1 000 probable patients were estimated by pour plate method. A total of 4 060 isolates were recovered, of these, 3 149 were recovered from both AEB and ANB, 461 from the AEB only, and 450 from the ANB only. The estimating median bacterial count in blood from 400 patients was 0.5 CFU/ml. The research findings demonstrate that the blood volume drawn is an important factor determining the yields from blood cultures. Growth of significantly more isolates was detected earlier in AEB.

Meta-analysis: pre-operative infliximab treatment and short-term post-operative complications in patients with ulcerative colitis

BACKGROUND

Infliximab was approved for use in ulcerative colitis in recent years. It has been debated if infliximab increases the risk of post-operative complications in patients with ulcerative colitis.

AIM

To perform a meta-analysis that examines the relationship between preoperative infliximab treatment and short-term post-operative complications in patients with ulcerative colitis.

METHODS

We searched the PubMed and MEDLINE databases to identify observational studies on the impact of pre-operative infliximab use on short-term post-operative complications in ulcerative colitis. Infectious complications mainly included wound infection, sepsis and abscess, whereas non-infectious complications included intestinal obstruction, thromboembolism and gastrointestinal haemorrhage. Pooled odds ratios (ORs) were calculated for each relationship.

RESULTS

A total of 5 studies and 706 patients were included in our meta-analysis. Overall, we did not find a strong association between pre-operative treatment of infliximab and short-term infectious [OR 2.24, 95% confidence interval (CI) 0.63-7.95] or non-infectious (OR 0.85, 95% CI 0.50-1.45) post-operative complications in ulcerative colitis patients. On the contrary, we discovered that pre-operative infliximab use increased short-term total post-operative complications (OR 1.80, 95% CI 1.12-2.87).

CONCLUSIONS

Pre-operative infliximab use increased the risk of short-term post-operative complications. Subgroup analysis is underpowered to assess the nature of these complications but shows a trend towards increased post-operative infection.

Neuroprotective effects of Dendrobium alkaloids on rat cortical neurons injured by oxygen-glucose deprivation and reperfusion

In this study we investigated the protective effects of alkaloids from Dendrobium spez. on cortical neurons injured by oxygen-glucose deprivation/reperfusion (OGD/RP) in vitro. Rat primary cultured cerebral cortical neurons were investigated at different time points of OGD/RP. The MTT assay and the lactate dehydrogenase (LDH) release were used to determine cell viability. The concentration of intracellular free calcium [Ca(2+)](i) and mitochondrial membrane potential (MMP) were determined to evaluate the degree of neuron damage. Morphologic changes of neurons following OGD/RP were examined by electron microscope. To evaluate neuron apoptosis, flow cytometry was performed and the expressions of caspase-3 and caspase-12 mRNA were examined by real-time quantitative PCR during OGD 2h/RP 12h. Treatment with Dendrobium alkaloids (0.025 approximately 2.5mg/l) significantly attenuated neuronal damage, with evidence of increased cell viability, decreased cell apoptosis, and decreased cell morphologic impairment. Furthermore, Dendrobium alkaloids inhibited [Ca(2+)](i) elevation, increased MMP and decreased the expressions of caspase-3 and caspase-12 in a concentration-dependent manner at OGD 2h/RP 12h. Dendrobium alkaloids have significantly protective effects on OGD/RP-induced neuronal damages in rat primary neuron cultures. The protection against OGD/RP-induced apoptosis appears to be mediated through blocking the decrease in MMP and increase in [Ca(2+)](i), as well as by down-regulating mRNA expression of caspase-3 and caspase-12.

Neuroprotective effects of Dendrobium alkaloids on rat cortical neurons injured by oxygen-glucose deprivation and reperfusion

In this study we investigated the protective effects of alkaloids from Dendrobium spez. on cortical neurons injured by oxygen-glucose deprivation/reperfusion (OGD/RP) in vitro. Rat primary cultured cerebral cortical neurons were investigated at different time points of OGD/RP. The MTT assay and the lactate dehydrogenase (LDH) release were used to determine cell viability. The concentration of intracellular free calcium [Ca(2+)](i) and mitochondrial membrane potential (MMP) were determined to evaluate the degree of neuron damage. Morphologic changes of neurons following OGD/RP were examined by electron microscope. To evaluate neuron apoptosis, flow cytometry was performed and the expressions of caspase-3 and caspase-12 mRNA were examined by real-time quantitative PCR during OGD 2h/RP 12h. Treatment with Dendrobium alkaloids (0.025 approximately 2.5mg/l) significantly attenuated neuronal damage, with evidence of increased cell viability, decreased cell apoptosis, and decreased cell morphologic impairment. Furthermore, Dendrobium alkaloids inhibited [Ca(2+)](i) elevation, increased MMP and decreased the expressions of caspase-3 and caspase-12 in a concentration-dependent manner at OGD 2h/RP 12h. Dendrobium alkaloids have significantly protective effects on OGD/RP-induced neuronal damages in rat primary neuron cultures. The protection against OGD/RP-induced apoptosis appears to be mediated through blocking the decrease in MMP and increase in [Ca(2+)](i), as well as by down-regulating mRNA expression of caspase-3 and caspase-12.

A model of expanding HIV/AIDS education in Chinese rural areas

The aim of the present study is to explore an effective model of HIV/AIDS health education for a rural Chinese population. Students in two middle schools were given HIV/AIDS health education. The education in Tiechang town was carried out in the form of delivering multimedia lectures, video tapes and brochures, while in Daping town brochures were distributed to students. After receiving health education, each student extended the health education to three peasants who were their relatives or neighbours. After the education was provided, the test scores of AIDS knowledge increased significantly in the students of Tiechang town (0.50 baseline, 0.69 post-test1, 0.68 post-test2). For the expansion subjects, the scores increased significantly (0.56 baseline versus 0.74 post-test) in the Tiechang group, and also increased mildly (0.52 baseline versus 0.59 post-test) in the Daping group. Empowering secondary school students to teach others about AIDS was a highly effective model for spreading AIDS prevention knowledge among the rural Chinese population.

Preparation and properties of banana fiber-reinforced composites based on high density polyethylene (HDPE)/Nylon-6 blends

Banana fiber (BaF)-filled composites based on high density polyethylene (HDPE)/Nylon-6 blends were prepared via a two-step extrusion method. Maleic anhydride grafted styrene/ethylene-butylene/styrene triblock polymer (SEBS-g-MA) and maleic anhydride grafted polyethylene (PE-g-MA) were used to enhance impact performance and interfacial bonding between BaF and the resins. Mechanical, crystallization/melting, thermal stability, water absorption, and morphological properties of the composites were investigated. In the presence of SEBS-g-MA, better strengths and moduli were found for HDPE/Nylon-6 based composites compared with corresponding HDPE based composites. At a fixed weight ratio of PE-g-MA to BaF, an increase of BaF loading up to 48.2 wt.% led to a continuous improvement in moduli and flexural strength of final composites, while impact toughness was lowered gradually. Predicted tensile modulus by the Hones-Paul model for three-dimensional random fiber orientation agreed well with experimental data at the BaF loading of 29.3 wt.%. However, the randomly-oriented fiber models underestimated experimental data at higher fiber levels. It was found that the presence of SEBS-g-MA had a positive influence on reinforcing effect of the Nylon-6 component in the composites. Thermal analysis results showed that fractionated crystallization of the Nylon-6 component in the composites was induced by the addition of both SEBS-g-MA and PE-g-MA. Thermal stability of both composite systems differed slightly, except an additional decomposition peak related to the minor Nylon-6 for the composites from the HDPE/Nylon-6 blends. In the presence of SEBS-g-MA, the addition of Nylon-6 and increased BaF loading level led to an increase in the water absorption value of the composites.

Characterization of two novel gene cassettes, dfrA27 and aadA16, in a non-O1, non-O139 Vibrio cholerae isolate from China

Two novel integron-borne cassettes, dfrA27 (encoding trimethoprim resistance) and aadA16 (encoding streptomycin and spectinomycin resistance), located on a conjugative plasmid, have been found in a non-O1, non-O139 Vibrio cholera isolate. DfrA27 shares 75% amino acid identity with DfrA5, and AadA16 shares 88% identity with AdaA6. Cloning of the cassette region and expression analysis demonstrated that the aadA16 gene can be expressed from its own promoter sequence, which is present upstream of the aadA16 cassette.