A Four-Plex Real-Time PCR Assay, Based on rfbE, stx1, stx2, and eae Genes, for the Detection and Quantification of Shiga Toxin-Producing Escherichia coli O157 in Cattle Feces

Several real-time polymerase chain reaction (PCR) assays have been developed to detect and quantify Shiga toxin-producing Escherichia coli (STEC) O157:H7, but none have targeted the O-antigen specific gene (rfbEO157) in combination with the three major virulence genes, stx1, stx2, and eae. Our objectives were to develop and validate a four-plex, quantitative PCR (mqPCR) assay targeting rfbE(O157), stx1, stx2, and eae for the detection and quantification of STEC O157 in cattle feces, and compare the applicability of the assay to detect STEC O157 to a culture method and conventional PCR (cPCR) targeting the same four genes. Specificity of the mqPCR assay to differentially detect the four genes was confirmed with strains of O157 and non-O157 STEC with different profiles of target genes. In cattle feces spiked with pure cultures, detection limits were 2.8×10(4) and 2.8×10(0) colony-forming units/g before and after enrichment, respectively. Detection of STEC O157 in feedlot cattle fecal samples (n=278) was compared between mqPCR, cPCR, and a culture method. The mqPCR detected 48.9% (136/278) of samples as positive for E. coli O157. Of the 100 samples that were randomly picked from 136 mqPCR-positive samples, 35 and 48 tested positive by cPCR and culture method, respectively. Of the 100 samples randomly chosen from 142 mqPCR-negative samples, all were negative by cPCR, but 21 samples tested positive by the culture method. McNemar's chi-square tests indicated significant disagreement between the proportions of positive samples detected by the three methods. In conclusion, the mqPCR assay that targets four genes is a novel and more sensitive method than the cPCR or culture method to detect STEC O157 in cattle feces. However, the use of real-time PCR as a screening method to identify positive samples and then subjecting only positive samples to a culture method may underestimate the presence of STEC O157 in fecal samples.

[Retrospective study about periodontal ligament healing of replanted permanent teeth in children]

OBJECTIVE

To analyze the prognosis about periodontal ligament healing of replanted permanent teeth in children and to examine the associated factors.

METHODS

The sample consisted of 49 children with 61 avulsed permanent teeth, whose injuries had been managed in the period from 2000 to 2012. The clinical data of replanted teeth were collected, and the follow-up period was no less than 12 months. The factors were analyzed in relation to postoperative outcomes, classified as functional periodontal healing (FH), infection-related (inflammatory) resorption (IRR) and replacement resorption (RR).

RESULTS

The functional healing rate was 23.0%, while replacement resorption rate was 72.1%. The replacement resorption (ankylosis) was usually observed earlier by clinical examination than by radiographic examination. 86.0% (40/47) resorptive processes were diagnosed within the first year. Physiological storages, such as milk, saline and saliva were significantly better to periodontal ligament healing than nonphysiological storages, such as tap water and sterilizing solutions (chloramine and alcohol). Functional healing was found significantly more frequent in canines and premolars.

CONCLUSION

The factor significantly affecting periodontal ligament healing is storage medium. Replacement resorption is the most common type of root resorption. The replacement resorption diagnosis must combine the radiographic examination with the clinical examination. It is better to follow up more than 1 year after tooth replantation.

KNOCKDOWN OF CASEIN KINASE 1e INHIBITS CELL PROLIFERATION AND INVASION OF COLORECTAL CANCER CELLS VIA INHIBITION OF THE Wnt/β-CATENIN SIGNALING

Deregulation of casein kinase 1 epsilon (CK1ε) is involved in the development of multiple pathological disorders such as cancer, however the function and molecular mechanism of CK1εin cancer are still unclear. In the present study, we aimed to investigate the role of CK1ε in human colorectal cancer (CRC). The expression of CK1ε was examined by immunohistochemical assay using a tissue microarray procedure. A loss-of-function experiment was performed to observe the effects of lentivirus-mediated CK1ε shRNA (Lv-shCK1ε) on cell proliferation and invasive potential by MTT and Transwell assays in CRC cell line (SW480). As a result, we found that the expression of CK1ε protein was significantly increased in CRC tissues compared with that in adjacent non-cancerous tissues (ANCT) (68.9% vs 42.2%, P=0.017) and was correlated with the Duke’s staging and depth of invasion in CRC patients (P=0.012; P=0.015). Knockdown of CK1ε reduced cell proliferation and invasion of CRC cells followed by the downregulation of wnt3α, β-catenin, PCNA and MMP-9. In conclusion, our findings show that high expression of CK1ε is positively associated with the Duke’s staging and depth of invasion in CRC patients, and knockdown of CK1ε suppresses the growth and invasion of CRC cells through inhibition of the wnt/β-catenin signaling, suggesting that CK1ε may serve as a promising therapeutic target for the treatment of CRC.

Effects of chlortetracycline and copper supplementation on the prevalence, distribution, and quantity of antimicrobial resistance genes in the fecal metagenome of weaned pigs

Use of in-feed antibiotics such as chlortetracycline (CTC) in food animals is fiercely debated as a cause of antimicrobial resistance in human pathogens; as a result, alternatives to antibiotics such as heavy metals have been proposed. We used a total community DNA approach to experimentally investigate the effects of CTC and copper supplementation on the presence and quantity of antimicrobial resistance elements in the gut microbial ecology of pigs. Total community DNA was extracted from 569 fecal samples collected weekly over a 6-week period from groups of 5 pigs housed in 32 pens that were randomized to receive either control, CTC, copper, or copper plus CTC regimens. Qualitative and quantitative PCR were used to detect the presence of 14 tetracycline resistance (tet) genes and to quantify gene copies of tetA, tetB, blaCMY-2 (a 3rd generation cephalosporin resistance gene), and pcoD (a copper resistance gene), respectively. The detection of tetA and tetB decreased over the subsequent sampling periods, whereas the prevalence of tetC and tetP increased. CTC and copper plus CTC supplementation increased both the prevalence and gene copy numbers of tetA, while decreasing both the prevalence and gene copies of tetB. In summary, tet gene presence was initially very diverse in the gut bacterial community of weaned pigs; thereafter, copper and CTC supplementation differentially impacted the prevalence and quantity of the various tetracycline, ceftiofur and copper resistance genes resulting in a less diverse gene population.

Two case reports of Castleman disease with pulmonary involvement

Castleman disease (CD) is a rare reactive lymphoproliferative disorder, first identified in 1954. We recently had the opportunity to analyse the characteristics of two variations of CD with pulmonary involvement. Case 1 had localised retroperitoneal hyaline vascular type CD, while Case 2 was diagnosed as multicentric plasma cell type CD. Both patients had pulmonary symptoms and signs, including cough, dyspnoea, hypoxaemia and ventilatory dysfunction; however, they had different physiological manifestations of their pulmonary abnormalities.

Biodegradable poly-lactic acid based-composite reinforced unidirectionally with high-strength magnesium alloy wires

Biodegradable poly-lactic acid (PLA)--based composites reinforced unidirectionally with high-strength magnesium alloy wires (MAWs) are fabricated by a heat-compressing process and the mechanical properties and degradation behavior are studied experimentally and theoretically. The composites possess improved strengthening and toughening properties. The bending strength and impact strength of the composites with 40 vol% MAWs are 190 MPa and 150 kJ/m(2), respectively, although PLA has a low viscosity and an average molecular weight of 60,000 g/mol. The mechanical properties of the composites can be further improved by internal structure modification and interface strengthening and a numerical model incorporating the equivalent section method (ESM) is proposed for the bending strength. Micro arc oxidization (MAO) of the MAWs is an effective interfacial strengthening method. The composites exhibit high strength retention during degradation and the PLA in the composite shows a smaller degradation rate than pure PLA. The novel biodegradable composites have large potential in bone fracture fixation under load-bearing conditions.

Large mesoporous carbons decorated with silver and gold nanoparticles by a self-assembly method: enhanced electrocatalytic activity for H2O2 electroreduction and sodium nitrite electrooxidation

The silver, gold nanoparticles were grown onto poly (diallyldimethyl ammoniumchloride, PDDA)-functionalized large mesoporous carbon (LMC) by simple self-assembly method. AuNPs or AgNPs/PDDA–LMC show superior electrocatalytic activity.

[Correlation between body composition and exercise capacity in patients with coronary heart disease]

OBJECTIVE

To provide the evidence for more accurately assessing the patient's body composition, predicting exercise capacity and guiding rehabilitation exercise by analyzing the body compositions in patients with coronary heart disease, and to study the correlation between body compositions and exercise capacity.

METHODS

The study enrolled 663 patients with coronary heart disease in NYHA I-II stages, who underwent coronary intervention therapy between December 2013 and August 2014. Between 15th and 20th days of the onset, cardiopulmonary exercising testing (CPET, Bruce Protocol) was conducted, and the body composition was measured with the Inboby720 body composition analyzer before CPET.

RESULTS

All the patients completed the body composition evaluation and the CPET. According to the three indicators of body mass index (BMI), percentage of body fat (PBF), waist-hip ratio (WHR), the diagnostic rate of obesity was 22.8%, 63.3%, and 72.7%, respectively. There was a good negative correlation between PBF and exercise capacity (r=-0.306, P<0.001). Compared with non-obesity patients, the exercise capacity of obesity group decreased according to PBF (P<0.01). The patients were divided into low, moderate and high exercise capacity groups according to METs, and the difference was only the PBF among the three groups (P<0.05).

CONCLUSION

PBF, measured by body composition, is a more accurate diagnosis of obesity and has a good negative correlation with exercise capacity, which can be used as an important indicator to predict the exercise capacity in patients with coronary heart disease and guide the rehabilitation exercise.

Room temperature plasmonic lasing in a continuous wave operation mode from an InGaN/GaN single nanorod with a low threshold

It is crucial to fabricate nano photonic devices such as nanolasers in order to meet the requirements for the integration of photonic and electronic circuits on the nanometre scale. The great difficulty is to break down a bottleneck as a result of the diffraction limit of light. Nanolasers on a subwavelength scale could potentially be fabricated based on the principle of surface plasmon amplification by stimulated emission of radiation (SPASER). However, a number of technological challenges will have to be overcome in order to achieve a SPASER with a low threshold, allowing for a continuous wave (cw) operation at room temperature. We report a nano-SPASER with a record low threshold at room temperature, optically pumped by using a cw diode laser. Our nano-SPASER consists of a single InGaN/GaN nanorod on a thin SiO₂ spacer layer on a silver film. The nanorod containing InGaN/GaN multi-quantum-wells is fabricated by means of a cost-effective post-growth fabrication approach. The geometry of the nanorod/dielectric spacer/plasmonic metal composite allows us to have accurate control of the surface plasmon coupling, offering an opportunity to determine the optimal thickness of the dielectric spacer. This approach will open up a route for further fabrication of electrically injected plasmonic lasers.

Inhibition enhancer of zeste homologue 2 promotes senescence and apoptosis induced by doxorubicin in p53 mutant gastric cancer cells

OBJECTIVES

Enhancer of zeste homologue 2 (EZH2) is crucially involved in epigenetic silencing by acting as a histone methyltransferase. Although EZH2 is overexpressed in many cancers and is involved in malignant cell proliferation and invasion, the role of EZH2 in senescence induced by DNA damage has up to now remained largely unknown. In this study, we sought to explore the outcome of EZH2 depletion along with exposure of doxorubicin (DOX), and related mechanisms, in gastric cancer cells.

MATERIALS AND METHODS

Here, senescence induced by DNA damage was achieved in gastric cancer cells by DOX treatment. EZH2 was downregulated by transfection with siRNA or treated with (-)-epigallocatechin-3-gallate, a targeted inhibitor. Senescence-associated β galactosidase (SA-β-gal) and formation of senescence-associated heterochromatin foci were used to identify cell senescence. To investigate effects of EZH2 depletion on the cell cycle, apoptosis and proliferation, flow cytometry and MTT analysis were employed. Changes in p53-p21 axis activation were detected by Western blotting.

RESULTS

We found that cell proliferative arrest caused by DOX could be promoted by EZH2 depletion. Mechanistically, EZH2 depletion not only worked in coordination with DNA damage during the progression of cell senescence but also promoted apoptosis in p53 mutant cells. However, it had no cooperative relationship with DOX in p53 wild-type cells.

CONCLUSIONS

These data help unravel a crucial role for EZH2 in senescence and apoptosis in gastric cancer cells and that p53 genomic status was associated with different cell responses to EZH2 silencing.

Submental cutaneous sinus tract of mandibular second molar origin

AIM

To report a case in which a submental cutaneous sinus tract resulted from apical periodontitis associated with a mandibular second molar.

SUMMARY

A 53-year-old man presented with a chronic cutaneous sinus tract in the submental region, which had previously been misdiagnosed as a thyroglossal fistula. The origin of the sinus tract was shown by sinus tract angiography to be the left mandibular second molar (tooth 37), which had apical periodontitis. The sinus tract healed after extraction of the tooth and partial excision of the lesion from an extraoral approach. Histological examination confirmed that the tract was lined with granulation tissue and not with epithelial tissue. A submental sinus tract drainage pathway was observed. Prompt dental evaluation, especially of all mandibular teeth, should be considered when assessing cases of submental cutaneous sinus tracts.

KEY LEARNING POINTS

An odontogenic origin should be part of the differential diagnosis for orofacial skin lesions. Cutaneous sinus tracts of mandibular molar origin are complex and thus a comprehensive examination should be stressed. It is necessary to examine all mandibular teeth in cases of odontogenic submental cutaneous sinus tracts. Sinus tract angiography can be used to identify the sinus tract pathway and to confirm the associated teeth. The treatment of an odontogenic cutaneous sinus tract requires the elimination of the source of infection.

Effects of chlortetracycline and copper supplementation on antimicrobial resistance of fecal Escherichia coli from weaned pigs

Feed-grade chlortetracycline (CTC) and copper are both widely utilized in U.S. pig production. Cluster randomized experiment was conducted to evaluate the effects of CTC and copper supplementation in weaned pigs on antimicrobial resistance (AMR) among fecal Escherichia coli. Four treatment groups: control, copper, CTC, or copper plus CTC were randomly allocated to 32 pens with five pigs per pen. Fecal samples were collected weekly from three pigs per pen for six weeks. Two E. coli isolates per fecal sample were tested for phenotypic and genotypic resistance against antibiotics and copper. Data were analyzed with multilevel mixed effects logistic regression, multivariate probit analysis and discrete time survival analysis. CTC-supplementation was significantly (99% [95% CI=98-100%]) associated with increased tetracycline resistance compared to the control group (95% [95% CI=94-97%]). Copper supplementation was associated with decreased resistance to most of the antibiotics tested, including cephalosporins, over the treatment period. Overall, 91% of the E. coli isolates were multidrug resistant (MDR) (resistant to ≥3 antimicrobial classes). tetA and blaCMY-2 genes were positively associated (P<0.05) with MDR categorization, while tetB and pcoD were negatively associated with MDR. tetA and blaCMY-2 were positively associated with each other and in turn, these were negatively associated with both tetB and pcoD genes; which were also positively associated with one another. Copper minimum inhibitory concentration was not affected by copper supplementation or by pcoD gene carriage. CTC supplementation was significantly associated with increased susceptibilities of E. coli to copper (HR=7 [95% CI=2.5-19.5]) during treatment period. In conclusion, E. coli isolates from the nursery pigs exhibited high levels of antibiotic resistance, with diverse multi-resistant phenotypic profiles. The roles of copper supplementation in pig production, and pco-mediated copper resistance among E. coli in particular, need to be further explored since a strong negative association of pco with both tetA and blaCMY-2 points to opportunities for selecting a more innocuous resistance profile.

Comparing real-time and conventional PCR to culture-based methods for detecting and quantifying Escherichia coli O157 in cattle feces

Detection of Escherichia coli O157 in cattle feces has traditionally used culture-based methods; PCR-based methods have been suggested as an alternative. We aimed to determine if multiplex real-time (mq) or conventional PCR methods could reliably detect cattle naturally shedding high (≥10(4) CFU/g of feces) and low (∼10(2) CFU/g of feces) concentrations of E. coli O157. Feces were collected from pens of feedlot cattle and evaluated for E. coli O157 by culture methods. Samples were categorized as (i) high shedders, (ii) immunomagnetic separation (IMS) positive after enrichment, or (iii) culture negative. DNA was extracted pre- and postenrichment from 100 fecal samples from each category (high shedder, IMS positive, culture negative) and subjected to mqPCR and conventional PCR assays based on detecting three genes, rfbE, stx1, and stx2. In feces from cattle determined to be E. coli O157 high shedders by culture, 37% were positive by mqPCR prior to enrichment; 85% of samples were positive after enrichment. In IMS-positive samples, 4% were positive by mqPCR prior to enrichment, while 43% were positive after enrichment. In culture-negative feces, 7% were positive by mqPCR prior to enrichment, and 40% were positive after enrichment. The proportion of high shedder-positive and culture-positive (high shedder and IMS) samples were significantly different from mqPCR-positive samples before and after enrichment (P < 0.01). Similar results were observed for conventional PCR. Our data suggest that mqPCR and conventional PCR are most useful in identifying high shedder animals and may not be an appropriate substitute to culture-based methods for detection of E. coli O157 in cattle feces.

Gas-phase chemistry of Mo, Ru, W, and Os metal carbonyl complexes

Metal carbonyl complexes were used for studying the gas-phase chemical behavior of Mo, Ru, W and Os isotopes with an on-line low temperature isothermal gas chromatography apparatus. Short-lived Mo and Ru isotopes were produced by a 252Cf spontaneous fission source. Short-lived nuclides of W and Os were produced using the heavy ion reactions 19F +159Tb and 165Ho, respectively. Short-lived products were thermalized in a recoil chamber filled with a gas mixture of helium and carbon monoxide. The carbonyls formed were then transported through capillaries to an isothermal chromatography column for study of the adsorption behavior as a function of temperature. On-line isothermal chromatography (IC) experiments on Teflon (PTFE) and quartz surfaces showed that short-lived isotopes of the listed elements can form carbonyl complexes which are very volatile and interact most likely in physical sorption processes. Deduced adsorption enthalpies of Mo and Ru carbonyls were − 38 ± 2 kJ/mol and − 36 ± 2 kJ/mol, respectively. These values are in good agreement with literature data, partly obtained with different chromatographic techniques. A validation of the applied Monte Carlo model to deduce adsorption enthalpies with Mo isotopes of different half-lives proved the validity of the underlying adsorption model. The investigations using a gas-jet system coupled to a heavy ion accelerator without any preseparator clearly showed the limitations of the approach. The He and CO gas mixture, which was directly added into the chamber, will result in decomposition of CO gas and produce some aerosol particles. After the experiment of 173W and 179Os in the heavy ion experiments, the Teflon column was covered by a yellowish deposit; the adsorption enthalpy of W and Os carbonyls could therefore not be properly deduced using Monte Carlo simulations.