Influence of canthaxanthin on broiler breeder reproduction, chick quality, and performance

To investigate the effect of canthaxanthin supplied via a maternal route on the production of both breeder hens and chickens, 270 Chinese Three-Yellow breeder hens were randomly divided into 2 groups consisting of 135 birds each (5 replicates of 27) for study. The breeder hens were fed either a basal diet or the basal diet supplemented with 6 mg of canthaxanthin/kg for 24 wk. At the end of the 24-wk breeder experiment, all hatching eggs laid in 5 consecutive days of each group were collected and incubated. For each breeder group, 100 newly hatched chicks (5 replicates of 20) were reared under environmentally controlled conditions for 21 d. Canthaxanthin supplementation resulted in the following outcomes: an enhancement of the serum total antioxidant capacity (TAC) of breeder hens (P = 0.029), a significant increase in the yolk colorimetric score of Roche Yolk Color Fan (RYCF; P < 0.001), and a significant improvement of the antioxidant status of the egg yolk (P < 0.05). The chicks that hatched from eggs laid by breeder hens fed the canthaxanthin supplementation diet demonstrated a higher pigmentation colorimetric score of RYCF for their shank skin (P < 0.05), and the antioxidant capacity of the newly hatched chicks was significantly increased (P < 0.05). Both of these positive effects on shank skin pigmentation colorimetric score of RYCF and antioxidant capacity were observed for at least 7 d posthatching, and the chicks that hatched from canthaxanthin-enriched eggs showed a lower mortality (0 vs. 4%) during the first 21 d posthatching. These findings support the hypothesis that canthaxanthin supplementation of the maternal diet enhances the protective capacity of tissues against oxidative stress in vivo, which might be beneficial for poultry producers.

Associations of serum salusin-alpha levels with atherosclerosis and left ventricular diastolic dysfunction in essential hypertension

Serum salusin-alpha, is decreased in essential hypertension and acute coronary syndrome. The study is aimed to explore whether serum salusin-alpha is associated with atherosclerosis and left ventricular (LV) diastolic dysfunction in essential hypertension. Echocardiography, carotid ultrasonography, brachial-ankle pulse wave velocity (BaPWV) and serum salusin-alpha levels were determined in 60 hypertensive patients (29 with and 31 without carotid plaque) and 30 normotensive controls. Hypertensive patients with plaque, compared with those without plaque or the controls, had the lowest values of salusin-alpha. Then the hypertensive patients were divided into left ventricular hypertrophy (LVH) and non-LVH groups according to the echocardiography. Similarly, hypertensive patients with LVH showed the lowest serum salusin-alpha levels. In all subjects, serum salusin-alpha levels were negatively correlated with carotid mean-intima-media thickness (IMT), BaPWV, left ventricle mass index (LVMI) and E/E' (r=-0.488, P<0.001; r=-0.381, P<0.001; r=-0.294, P=0.006; r=-0.303, P=0.005; respectively). Serum salusin-alpha levels were independent predictors of BaPWV, carotid strain, carotid distensibility, mean-IMT, LVMI and E'/A' (β=-0.399, 0.283, 0.237, -0.346, -0.306, 0.469; P=0.002, 0.031, 0.016, 0.005, 0.012 and 0.001, respectively) in multiple linear regression models. These results suggest that serum salusin-alpha may be associated with atherosclerosis and LV diastolic dysfunction in essential hypertension.

First Report of Pepino mosaic virus Infecting Tomato in Mexico

Pepino mosaic virus (PepMV) (genus Potexvirus) was first reported in Europe to be infecting greenhouse tomatoes (Solanum lycopersicum) in 2000 (3). Subsequently, it has also been identified in Canada and the United States (1) and has become widespread on greenhouse tomatoes in many countries. In early spring of 2010, symptoms including chlorotic mosaic or chlorotic patches on leaves, necrotic stems, and fruit deformation or marbling were noted. Approximately 50% of plants in a greenhouse in Jocotitlan, Mexico exhibited symptoms. Twenty-three symptomatic samples in four separate collections between April 2010 and January 2011 all tested positive for the presence of PepMV by ELISA and/or Agristrips (BioReba, Switzerland). Two symptomless samples were negative for PepMV. Biological inoculation with the isolate MX10-05 to three Nicotiana benthamiana and three tomato cv. Horizon plants all resulted in chlorotic mosaic symptoms on the systemic leaves and PepMV on the inoculated plants was confirmed by ELISA. To determine the genotype of PepMV in MX10-05, two primer sets targeting different part of the virus genome (separated by 2,744 nt) were selected for reverse transcription (RT)-PCR using total plant RNA extracted with the RNeasy Plant Mini Kit (Qiagen, Valencia, CA). A RT-PCR product (840 bp) was obtained using the first primer set (PepMV-Ch2.F541: 5'CATGGAACCAGCTGATGTGA and PepMV-Ch2.R1380: 5'TCTTTGTATATGGTCGCAGC) targeting the 5' portion of the RNA-dependent RNA polymerase (RdRp) gene. The PCR product was cloned in pCR2.1 using the TOPO TA cloning system (Invitrogen, Carlsbad, CA) and a single clone was sequenced in both directions (Functional Biosciences, Madison, WI). After primer trimming, the 800-bp sequence (GenBank Accession No. JF811600) was shown in BLASTn to have its highest nucleotide sequence identity (99.4%) to the type PepMV-CH2 (DQ000985), 98% to other CH2/US2 isolates, 85% to US1, and 84% to EU. Another RT-PCR product (also 840 bp) was generated using the second primer set (PepMV-Ch2.F4081: 5'AAAAACGCTGTACCCAAAAC and PepMV-Ch2.R4920: 5'CAGAAATGTGTTCAGAGGGG) targeting the 3' portion of RdRp and TGB1 genes. This second genome segment enables the differentiation of the CH2 and US2 genotypes. The resulting 800 bp (JF811600) had the highest nucleotide sequence identity (99.5%) to the type PepMV CH2, 97% to other CH2 isolates, 83% to US2, and only 81% to the EU genotype. Taken together, these sequence analyses support the identification of MX10-05 as a PepMV-CH2 isolate (2). However, the presence of other PepMV genotypes cannot be excluded once sequences from other isolates are obtained and analyzed. To our knowledge, this is the first report of PepMV on greenhouse tomatoes in Mexico. References: (1). C. J. French et al. Plant Dis. 85:1121, 2001. (2). K.-S. Ling. Virus Genes 34:1, 2007. (3). R. A. A. van der Vlugt et al. Plant Dis. 84:103, 2000.

Mixed methods research in mental health nursing

Mixed methods research is becoming more widely used in order to answer research questions and to investigate research problems in mental health and psychiatric nursing. However, two separate literature searches, one in Scotland and one in the USA, revealed that few mental health nursing studies identified mixed methods research in their titles. Many studies used the term 'embedded' but few studies identified in the literature were mixed methods embedded studies. The history, philosophical underpinnings, definition, types of mixed methods research and associated pragmatism are discussed, as well as the need for mixed methods research. Examples of mental health nursing mixed methods research are used to illustrate the different types of mixed methods: convergent parallel, embedded, explanatory and exploratory in their sequential and concurrent combinations. Implementing mixed methods research is also discussed briefly and the problem of identifying mixed methods research in mental and psychiatric nursing are discussed with some possible solutions to the problem proposed.

First Report of 'Candidatus Liberibacter solanacearum' Naturally Infecting Tomatoes in the State of Mexico, Mexico

In January 2011, tomato (Solanum lycopersicum) plants exhibiting stunting, yellow mosaic, short, chlorotic leaves, aborted flowers, and reduced-size fruits, symptoms similar to those exhibited by plants infected by 'Candidatus Liberibacter solanacearum' (2), were observed in approximately 5% of tomato plants in greenhouses in Jocotitlan in the State of Mexico, Mexico. Occasional plant recovery was also observed. Tomato plants in this facility were previously shown to be infected by Mexican papita viroid (MPVd), Pepino mosaic virus (PepMV), and aster yellows phytoplasma. Eight symptomatic leaf samples (designated MX11-01 to MX11-08) were collected and screened against selected tomato viruses and pospiviroids by reverse transcription (RT)-PCR using purified plant RNA or for 'Ca. L. solanacearum' by PCR using purified plant DNA. As expected, both PepMV and MPVd were detected in these samples. However, two 'Ca. L. solanacearum'-specific PCR products (1,168 and 669 bp) were also amplified in two samples (MX11-02 and MX11-05) using primers OA2 (2) and OI2c (1) or CL514F/CL514R (3), respectively. Each 'Ca. L. solanacearum'-specific PCR product was gel purified with Geneclean (Q-Biogene, Carlsbad, CA) and cloned into pCR2.1 using TOPO TA cloning kit (Invitrogen, Carlsbad, CA) and sequenced (Functional Biosciences, Madison, WI). Sequences of 16S rRNA (1,168 bp) in both isolates (GenBank Accession Nos. JF811596 and JF811597) were identical. However, the 669-bp 50S rRNA sequences in these two isolates (GenBank Accession Nos. JF811598 and JF811599) contained two single nucleotide polymorphism (SNP) mutations. BLASTn searches showed that both 16S rRNA and 50S gene sequences in MX11-05 were identical to the 'Ca. L. solanacearum' previously identified on potato in Chihuahua (GenBank Accession Nos. FJ829811 and FJ829812) and Saltillo (GenBank Accession Nos. FJ498806 or FJ498807) in eastern Mexico. These 'Ca. L. solanacearum' isolates were recently classified as the "b" haplotype (4). Alignment analysis of the 'Ca. L. solanacearum' 16S rRNA sequences also revealed the conserved SNP mutations (g.212T > G and g.581T > C) in MX11-02 and MX11-05 as previously identified for other "b" haplotype isolates (4). 'Ca. L. solanacearum' was first identified in greenhouse tomatoes in 2008 in New Zealand (2). It has also been identified in greenhouse and field tomatoes in the United States. 'Ca. L. solanacearum' was previously reported to infect field tomatoes in Sinaloa, Mexico (3), which was recently considered as the "a" haplotype (4). To our knowledge, this is the first report of 'Ca. L. solanacearum' naturally infecting tomatoes in Jocotitlan in the State of Mexico, Mexico. The greenhouse tomato 'Ca. L. solanacearum' may be transmitted from infected solanaceous plants by potato psyllids (Bactericera cockerelli), which were observed in this facility. References: (1) S. Jagoueix et al. Int. J. Syst. Bacteriol. 44:379, 1994. (2) L. W. Liefting et al. Plant Dis. 93:208, 2009. (3) J. E. Munyaneza et al. Plant Dis. 93:1076, 2009 (4) W. R. Nelson et al. Eur. J. Plant Pathol. 130:5, 2011.

Adoptive cell therapy using antigen-specific CD4⁻CD8⁻T regulatory cells to prevent autoimmune diabetes and promote islet allograft survival in NOD mice

AIMS/HYPOTHESIS

A new differentiation pathway for CD4(-)CD8(-) (DN) T cells has recently been identified that exhibits the potent function of peripheral converted DN T cells in suppressing immune responses and provides the potential to treat autoimmune diseases. The aim of this study was to determine if the DN T cells converted from CD4(+) T cells of NOD mice retain the antigen-specific regulatory capacity and prevent autoimmune diabetes in vivo. We also sought to determine if the combination of DN T cells with rapamycin promotes islet allograft survival in autoimmune diabetic NOD recipients.

METHODS

NOD CD4(+) T cells were converted to DN T cells in an in vitro mixed-lymphocyte reaction, with or without GAD65 peptide, as previously reported. The antigen-specific DN T cells were adoptively transferred to NOD/SCID mice, new-onset diabetic NOD mice or islet-allograft-recipient NOD mice as the part of cell-based therapy. The development of diabetes and allograft survival was assessed by monitoring blood glucose levels.

RESULTS

NOD CD4(+) T cells were converted in vitro to DN T cells at a rate of 50% and expressed unique cell features. The DN T cells from NOD donors blocked autoimmunity and prevented diabetes in NOD models, and these effects were even greater for GAD65-peptide-primed DN T cells. DN T cells acted in conjunction with rapamycin to suppress alloantigen-triggered T cell proliferation, promoted apoptosis and prolonged islet allograft survival in NOD recipients.

CONCLUSIONS/INTERPRETATION

Administration of the islet beta cell antigen-specific DN T cells can prevent the development of autoimmune diabetes and promote islet allograft survival in NOD mice.

Effect of a high-fat meal on the pharmacokinetics of dapagliflozin, a selective SGLT2 inhibitor, in healthy subjects

Dapagliflozin is a potent and selective inhibitor of sodium-glucose co-transporter type 2 that is being developed for the treatment of type 2 diabetes mellitus. This open-label, randomized, two-period, two-treatment (single doses of 10-mg dapagliflozin fasted or fed), crossover study was conducted to evaluate the effect of a high-fat meal on the pharmacokinetics of dapagliflozin in 14 healthy subjects. Compared to the fasted state, a high-fat meal decreased mean dapagliflozin maximum plasma concentrations (C(max) ) by 31%, increased the time to C(max) (T(max) ) by 1 h, but did not affect overall dapagliflozin systemic exposure [area under the plasma concentration-time curve (AUC)]. As the cumulative (daily) amount of glucose excreted in the urine induced by dapagliflozin is dependent upon dapagliflozin AUC, the effect of food on dapagliflozin C(max) is unlikely to have a clinically meaningful effect on dapagliflozin's efficacy. On the basis of these findings, dapagliflozin can be administered without regard to meals.

Current progress of the biological single-ion microbeam at FUDAN

A biological microbeam for precisely positioned single-ion/single cell irradiation is built in the Institute of Modern Physics in Fudan University, Shanghai, China, based on the tandem accelerator (2 × 3MV) in the laboratory. In this paper, the developing progress of the FUDAN microbeam is reported, including the newly constructed beam line, the microbeam collimator, the ion detection system, and the cell-imaging and targeting systems. Statistical models are proposed for evaluating the spatial resolution and dosage precision of the microbeam. By taking the collimated ions as a Gaussian beam, the spatial resolution can be evaluated by the full width at half maximum of the 2-D Gaussian distribution, which is determined by fitting the proportions of peripheral pits outside specific radii in the pit clusters etched on ion track detectors to a 2-D Gaussian distribution. In the preset hitting of defined ion number, by taking the real delivered number of ions as an independent identically distributed random variable (iidrv), according to the Law of Large Numbers and Central Limit Theorem, the expected value μ and standard deviation σ of the real delivered ion number in a preset N-ion hitting can be determined by approaching the normal distribution of N (μ, σ (2)/n) with the proportions of the mean counts of pits in multiple pit clusters on ion track detectors. By the values of μ, σ and additional assumptions, statistical dosage precision evaluations can be made on the preset hitting. From the linear fit curve of μ(N) and the power function fit curve of σ(N) on different preset ion numbers, characteristic factors k, b, A, p can be extracted for a precision evaluation independent of the specific preset ion number.

The polymorphisms in the VHL and HIF1A genes are associated with the prognosis but not the development of renal cell carcinoma

BACKGROUND

The von Hippel-Lindau (VHL) tumor suppressor gene and hypoxia-inducible factor-1α (HIF1A) play a pivotal role in renal carcinogenesis. This study was aimed to clarify the influence of VHL and HIF1A polymorphisms on renal cell cancer (RCC) susceptibility and survival.

SUBJECTS AND METHODS

We genotyped four potentially functional single-nucleotide polymorphisms (rs779805 in VHL and rs11549465, rs11549467, and rs2057482 in HIF1A) and assessed their associations with RCC risk, clinicopathologic parameters in a case-control study of 620 patients and 623 controls, and the prognosis of RCC in a cohort of 311 patients.

RESULTS

No significant differences in VHL or HIF1A genotypes were observed between RCC cases and controls. However, individuals with ≥2 variant alleles of the four polymorphisms were associated with less frequent lymph node metastasis and lower clinical stage (P = 0.032 and P = 0.041, respectively). And the number of variant alleles was associated with improved survival in a dose-response manner (P(trend) = 0.013). Furthermore, multivariate Cox regression analysis showed that the number of variant alleles (≥1 versus 0) was an independent prognostic factor for RCC survival (P = 0.036) together with clinical stage and tumor grade.

CONCLUSION

The VHL and HIF1A polymorphisms may not influence RCC susceptibility but may jointly influence RCC progression and survival.

Identification of a novel HLA-DRB1 allele, HLA-DRB1*12:27, in a Chinese individual

Nucleotide sequence of HLA-DRB1*12:27 allele was different from that of HLA-DRB1*12:02:01 by three-nucleotide substitution at position 165A>C, 171G>C, and 175C>T.

Phase I/II study of hypofractioned radiation with three-dimensional conformal radiotherapy for clinical T3-4N0-1M0 stage esophageal carcinoma

Compared to conventional fractionated-dose radiotherapy, high hypofractionated-dose radiotherapy could yield tumoricidal effects. However, few clinical trials of hypofractionated radiotherapy in loco-regionally advanced incurable esophageal cancer at present have yet been performed. The purpose of the current study was to evaluate the efficacy and toxicity of hypofractioned radiation with three-dimensional conformal radiotherapy for clinical T3-4N0-1M0 stage esophageal carcinoma. From September 2003 to December 2005, 45 patients with locally advanced esophageal carcinoma were grouped and received three-dimensional conformal hypofractioned radiotherapy (3D-CRT) whose fractionated dose was gradually increase per group. Radiotherapy was administered to a total dose of from 50 to 54 Gy (fractionated dose of from 3.0 to 6.0 Gy, 3 times weekly), over a 3-4 week period. And patients received 4 cycles chemotherapy. The median follow-up period for survivors was 38 months. Treatment tolerance rate was 78.8% with daily dose of from 3 to 5 Gy. There are 21.2% patients occurring Grade ≥ 3 acute toxicities. But patients couldn't tolerate daily dose of 6 Gy (55.6%). The 1-year, 2-year and 3-year local control rates were 62%, 49% and 39% respectively. And the 1-year, 2-year and 3-year overall survival rates were 34%, 21% and 9% respectively. The median overall survival time was 17 months. At the time of following up, 13 patients (31.0%) had occurred esophageal late complications, with mainly esophageal perforation, hemorrhage or stenosis, including initial stenosis aggravation. Therefore hypofractionated irradiation was thought to be feasible for clinical T3-4N0-1M0 stage esophageal carcinoma. And daily dose of ≤5 Gy was comparatively suitable in hypofractionated irradiation for esophageal carcinoma, and the patients tolerated well. But further research was in need also.

Enhanced antitumor effects of tumor antigen-pulsed dendritic cells by their transfection with GM-CSF gene

To investigate the biological characterization and antitumor activities of GM-CSF gene-transfected dendritic cells, the splenic dendritic cells were infected with GM-CSF recombinant replication-deficient adenovirusesin vitro. Their enhanced expression of B7 was demonstrated by FACS analysis, and more potent stimulatory activity was confirmed by allogeneic MLR. Immunization of dendritic cells pulsed with irradiated B16 melanoma cells induced significant CTL and enabled host to resist the challenge of wild-type B16 cells. When they were transfected with GM-CSF gene subsequently, the induced CTL activity was higher, and the produced protection against B16 cell challenge and therapeutic effect on the mice with preestablished pulmonary metastases more effective. These data suggest that the dendritic cells pulsed with tumor antigen then transfected with GM-CSF gene can be used as an effective vaccine in tumor immunotherapy.

Correlation between expression of cadherin and gap junctional communication in human lung carcinoma cells

The correlation between expression of ca(2+)-dependent cell adhesion molecule, cadherin, and gap junctional intercellular communication (GJIC) in human lung carcinoma PG cell line and connexin43 (Cx43) cDNA transfected PG cell clones was investigated. Results from immunoblotting and immunofluorescent staining revealed that cultured normal human lung cells (RF) expressed N-cadherin. However, the expression level of Kcadherin in PG cells was very low in comparison with normal RF cells. The Cx43 transfected PG clones exhibited comparable levels of Cx43 protein, but varied in the level of N-cadherin expression and in the function of GJIC as measured by scrape-loading and dye transfer (SLDT) method. Positive correlation between N-cadherin and GJIC was demonstrated. Thein vitro andin uivo, growth examination results suggest that N-cadherin mediated cell-cell adhesions and Cx43 functional expression, the GJIC, may work coordinately with each other in regulation of cell growth and differentiation. Deficiency in both GJIC and cell adhesion may be crucial for cell transformation.

Continuous production and recovery of recombinant Ca2+ binding receptor from HEK 293 cells using perfusion through a packed bed bioreactor

The extracellular domain of human parathyroid Ca(2+) receptor was needed in order to study itsstructure and clinical application. The Ca(2+)receptor is a unique member of the G protein-coupledreceptor super-family, expressed in parathyroid andkidney cells where it has been shown to play acritical role in extracellular calcium homeostasis.The desired protein was produced by immobilizing thetransformed HEK 293 cells in a packed-bedconfiguration using a 1.6 l (working volume)bioreactor equipped with a vertical mixing impellerassembly and an internal basket. The process includeda propagation phase followed by a production phase. Inthe propagation phase, lasting approximately 160 h, the bed was perfused with a serum-containingmedium, allowing the cells to grow at a constantgrowth rate to approximately 3 x 10(10). At this point the production phase was begun, replacing themedium with serum-free medium and continuing theperfusion process for additional 350 h. Duringthis phase, the medium was pumped through the packedbed at a rate of 4-6 l per day, keeping theresidual glucose concentration around 1 g l(-1) andcollecting and processing approximately 80 l ofspent medium. This continuous perfusion method of thepacked-bed bioreactor was compared to a repeated batchmethod in which existing medium was replenished whenthe glucose concentration was down to 1 g l(-1). Using this method, serum-free medium was replaced withserum containing medium a few times when a decline inthe glucose consumption was observed. Though mediumconsumption and protein yield are similar in bothmethods (roughly 10 mg l(-1)), there aredifferences related to the ease of operation andprocessing of the produced protein. The continuousperfusion operation was found to be preferable and waschosen as the production strategy.

In vitro study of enhanced osteogenesis induced by HIF-1α-transduced bone marrow stem cells

OBJECTIVES

Hypoxia-inducible factor 1α (HIF-1α) is a pivotal regulator of hypoxic and ischaemic vascular responses that drives transcriptional activation of hundreds of genes involved in vascular reactivity, angiogenesis and arteriogenesis. Previous reports based on gene knockout technology have demonstrated that HIF-1α can promote osteogenesis. However, this protein is easily degraded in a normoxic state, which makes in vitro studies of HIF-1α-induced mesenchymal stem cell (MSC) osteogenesis difficult. For better understanding of HIF-1α promoting osteogenesis, the role of HIF-1α-induced MSC osteogenesis in the normoxic state has been investigated here.

MATERIALS AND METHODS

HIF-1α was made to overexpress using a lentiviral vector, and its effects on bone marrow-derived mesenchymal stem cell (BMSC) osteogenesis were investigated. Real-time quantitative and western blotting (to assess expression levels of angiogenic and osteogenic related genes regulated by Lenti-HIF-1α), alkaline phosphatase (ALP) and alizarin red-S staining analyses, were performed.

RESULTS

In HIF-1α gene-transfected BMSCs, expression levels of angiogenic, cartilaginous and osteogenic genes were all increased significantly compared to Lenti LacZ-transfected cells, at both mRNA and protein levels. ALP activity and alizarin red-S staining were significantly enhanced in HIF-1α transduced cells compared to control cells, on day 21.

CONCLUSIONS

These results indicate that Lenti-HIF-1α can induce BMSC overexpression levels of angiogenic and osteogenic genes in vitro in the normoxic state. Further study will be focused on whether HIF-1α can also improve bone repair in vivo.

Characterization of 236 novel alleles at the HLA-A, -B, -C, -DRB1, -DQB1 and -DPB1 loci from China Marrow Donor Program

Two hundred and thirty-six novel human leukocyte antigen (HLA) alleles are described from volunteer donors of the China Marrow Donor Program: 71 HLA-A alleles, 79 HLA-B alleles, 43 HLA-C, 16 HLA-DRB1 alleles, 26 HLA-DQB1 and 1 HLA-DPB1. Two hundred and thirteen (90.3%) of the 236 novel alleles are single nucleotide substitution variants when compared with their most homologous allele. Seventy-eight of these single nucleotide variants are silent substitutions. The remaining novel alleles differ from their most similar allele by two to four nucleotide substitutions. Some of the novel alleles encode amino acid changes at positions not previously reported to be polymorphic, such as codons 57, 62, 67, 41 and 52 in HLA-A alleles; codons 133, 156, 201 and 215 in HLA-B alleles; codons 74, 208 and 225 in HLA-C; codons 25, 32 and 72 in HLA-DRB1; codons 20, 39 and 77 in HLA-DQB1.

MiR-200b and miR-15b regulate chemotherapy-induced epithelial-mesenchymal transition in human tongue cancer cells by targeting BMI1

Chemotherapy has been reported to induce epithelial-mesenchymal transition (EMT) in tumor cells, which is a critical step in the process of metastasis leading to cancer spreading and treatment failure. However, the underlying mechanisms of chemotherapy-induced EMT remain unclear, and the involvement of microRNAs (miRNA) in this process is poorly understood. To address these questions, we established stable chemotherapy-resistant tongue squamous cell carcinoma (TSCC) cell lines CAL27-res and SCC25-res by exposing the parental CAL27 and SCC25 lines to escalating concentrations of cisplatin for 6 months. CAL27-res and SCC25-res cells displayed mesenchymal features with enhanced invasiveness and motility. MiRNA microarray illustrated that miR-200b and miR-15b were the most significantly downregulated microRNAs in CAL27-res cells. Ectopic expression of miR-200b and miR-15b with miRNA mimics effectively reversed the phenotype of EMT in CAL27-res and SCC25-res cells, and sensitized them to chemotherapy, but inhibition of miR-200b and miR-15b in the sensitive lines with anti-sense oligonucleotides induced EMT and conferred chemoresistance. Retrieving the expression of B lymphoma Mo-MLV insertion region 1 homolog (BMI1), a target for miR-200b and miR-15b, in the presence of the miRNA mimics by transfecting CAL27-res cells with pcDNA3.1-BMI1-carrying mutated seed sequences of miR-200b or miR-15b at its 3'-UTR recapitulated chemotherapy-induced EMT. In vivo, enforced miR-200b or miR-15b expression suppressed metastasis of TSCC xenografts established by CAL27-res cells. Clinically, reduced miR-200b or miR-15b expression was associated with chemotherapeutic resistance in TSCCs and poor patient survival. Our data suggest that reduced expression of miR-200b and miR-15b underscores the mechanisms of chemotherapy-induced EMT in TSCC, and may serve as therapeutic targets to reverse chemotherapy resistance in tongue cancers.

Social consensus through the influence of committed minorities

We show how the prevailing majority opinion in a population can be rapidly reversed by a small fraction p of randomly distributed committed agents who consistently proselytize the opposing opinion and are immune to influence. Specifically, we show that when the committed fraction grows beyond a critical value p(c) ≈ 10%, there is a dramatic decrease in the time T(c) taken for the entire population to adopt the committed opinion. In particular, for complete graphs we show that when p < pc, T(c) ~ exp [α(p)N], whereas for p>p(c), T(c) ~ ln N. We conclude with simulation results for Erdős-Rényi random graphs and scale-free networks which show qualitatively similar behavior.