Pancreatic stellate cell secreted IL-6 stimulates STAT3 dependent invasiveness of pancreatic intraepithelial neoplasia and cancer cells

Pancreatic ductal adenocarcinoma (PDAC) is a dynamic tumor supported by several stromal elements such as pancreatic stellate cells (PSC). Significant crosstalk exists between PSCs and tumor cells to stimulate oncogenic signaling and malignant progression of PDAC. However, how PSCs activate intercellular signaling in PDAC cells remains to be elucidated. We have previously shown that activated signal transducer and activator of transcription 3 (STAT3) signaling is a key component in the progression of pancreatic neoplasia. We hypothesize that PSC secreted IL-6 activates STAT3 signaling to promote PanIN progression to PDAC. Human PDAC and mouse PanIN cells were treated with PSC-conditioned media (PSC-CM), and phospho- and total-STAT3 levels by immunoblot analysis were determined. IL-6 was quantified in PSC-CM and cell invasion and colony formation assays were performed in the presence or absence of a neutralizing IL-6 antibody and the JAK/STAT3 inhibitor AZD1480. Serum from Ptf1aCre/+;LSL-KrasG12D/+;Tgfbr2flox/flox (PKT) and LSL-KrasG12D/+; Trp53R172H/+; Pdx1Cre/+ (KPC) mice demonstrated increased levels of IL-6 compared to serum from non-PDAC bearing KC and PK mice. PSC secreted IL-6 activated STAT3 signaling in noninvasive, precursor PanIN cells as well as PDAC cells, resulting in enhanced cell invasion and colony formation in both cell types. There was a significant positive linear correlation between IL-6 concentration and the ratio of phosphorylated STAT3/total STAT3. IL-6 neutralization or STAT3 inhibition attenuated PSC-CM induced activation of STAT3 signaling and tumorigenicity. These data provide evidence that PSCs are directly involved in promoting the progression of PanINs towards invasive carcinoma. This study demonstrates a novel role of PSC secreted IL-6 in transitioning noninvasive pancreatic precursor cells into invasive PDAC through the activation of STAT3 signaling.

Observation of Weyl nodes and Fermi arcs in tantalum phosphide

A Weyl semimetal possesses spin-polarized band-crossings, called Weyl nodes, connected by topological surface arcs. The low-energy excitations near the crossing points behave the same as massless Weyl fermions, leading to exotic properties like chiral anomaly. To have the transport properties dominated by Weyl fermions, Weyl nodes need to locate nearly at the chemical potential and enclosed by pairs of individual Fermi surfaces with non-zero Fermi Chern numbers. Combining angle-resolved photoemission spectroscopy and first-principles calculation, here we show that TaP is a Weyl semimetal with only a single type of Weyl fermions, topologically distinguished from TaAs where two types of Weyl fermions contribute to the low-energy physical properties. The simple Weyl fermions in TaP are not only of fundamental interests but also of great potential for future applications. Fermi arcs on the Ta-terminated surface are observed, which appear in a different pattern from that on the As-termination in TaAs and NbAs.

Breastfeeding and childhood acute otitis media: a systematic review and meta-analysis

AIM

To synthesise the evidence on the association between duration and exclusivity of breastfeeding and the risk of acute otitis media (AOM).

METHODS

Systematic review and meta-analysis following searching of PubMed, CINAHL and EMBASE electronic databases.

RESULTS

Twenty-four studies, all from the USA or Europe, met the inclusion criteria. In the pooled analyses, any form of breastfeeding was found to be protective for AOM in the first 2 years of life. Exclusive breastfeeding for the first 6 months was associated with the greatest protection (OR 0.57 95% CI 0.44, 0.75), followed by 'more vs less' breastfeeding (OR 0.67; 0.59, 0.76) and 'ever vs never' breastfeeding (OR 0.67; 0.56, 0.80).

CONCLUSION

This systematic review and meta-analysis provides evidence that breastfeeding protects against AOM until 2 years of age, but protection is greater for exclusive breastfeeding and breastfeeding of longer duration. Exclusive breastfeeding during the first 6 months was associated with around a 43% reduction in ever having AOM in the first 2 years of life. After 2 years of age, there is no evidence that breastfeeding protects against AOM; however, there were few studies and the evidence quality was low.

Breastfeeding and asthma and allergies: a systematic review and meta-analysis

AIM

To systematically review the association between breastfeeding and childhood allergic disease.

METHODS

Predetermined inclusion/exclusion criteria identified 89 articles from PubMed, CINAHL and EMBASE databases. Meta-analyses performed for categories of breastfeeding and allergic outcomes. Meta-regression explored heterogeneity.

RESULTS

More vs. less breastfeeding (duration) was associated with reduced risk of asthma for children (5-18 years), particularly in medium-/low-income countries and with reduced risk of allergic rhinitis ≤5 years, but this estimate had high heterogeneity and low quality. Exclusive breastfeeding for 3-4 months was associated with reduced risk of eczema ≤2 years (estimate principally from cross-sectional studies of low methodological quality). No association found between breastfeeding and food allergy (estimate had high heterogeneity and low quality). Meta-regression found differences between study outcomes may be attributable to length of breastfeeding recall, study design, country income and date of study inception. Some of the protective effect of breastfeeding for asthma may be related to recall bias in studies of lesser methodological quality.

CONCLUSION

There is some evidence that breastfeeding is protective for asthma (5-18 years). There is weaker evidence for a protective effect for eczema ≤2 years and allergic rhinitis ≤5 years of age, with greater protection for asthma and eczema in low-income countries.

Breastfeeding and the risk of dental caries: a systematic review and meta-analysis

AIM

To synthesise the current evidence for the associations between breastfeeding and dental caries, with respect to specific windows of early childhood caries risk.

METHODS

Systematic review, meta-analyses and narrative synthesis following searches of PubMed, CINAHL and EMBASE databases.

RESULTS

Sixty-three papers included. Children exposed to longer versus shorter duration of breastfeeding up to age 12 months (more versus less breastfeeding), had a reduced risk of caries (OR 0.50; 95%CI 0.25, 0.99, I(2) 86.8%). Children breastfed >12 months had an increased risk of caries when compared with children breastfed <12 months (seven studies (OR 1.99; 1.35, 2.95, I(2) 69.3%). Amongst children breastfed >12 months, those fed nocturnally or more frequently had a further increased caries risk (five studies, OR 7.14; 3.14, 16.23, I(2) 77.1%). There was a lack of studies on children aged >12 months simultaneously assessing caries risk in breastfed, bottle-fed and children not bottle or breastfed, alongside specific breastfeeding practices, consuming sweet drinks and foods, and oral hygiene practices limiting our ability to tease out the risks attributable to each.

CONCLUSION

Breastfeeding in infancy may protect against dental caries. Further research needed to understand the increased risk of caries in children breastfed after 12 months.

Study of PIK3CA, BRAF, and KRAS mutations in breast carcinomas among Chinese women in Qinghai

Phosphatidylinositol-3-OH kinase and RAS-activated signaling pathways play an important role in tumor formation. Abnormalities in relevant genes play essential roles in the occurrence and development of many human cancers. Studies of breast cancer have mainly focused on the women in western countries, but few studies have examined the frequency of mutations in PIK3CA, BRAF, and KRAS in Chinese breast cancer patients. In this study, we conducted sequence analysis of PIK3CA, BRAF, and KRAS and determined relationships with the occurrence of breast cancer in women from Qinghai. DNA was extracted from 25 cases of human breast cancer tissue samples. PIK3CA, BRAF, and KRAS mutation analysis was performed by polymerase chain reaction and DNA sequencing. No mutations were found in PIK3CA, BRAF, and KRAS of adjacent tissues. However, PIK3CA mutations were observed in 32% (8) of the 25 breast cancer tissues examined, in which exon 9 accounted for 4% (1), exon 20 accounted for 28% (7), and no mutations were found in exon 1 of PIK3CA. Sequencing of exon 2 of KRAS suggested that 20% (5) of the 25 samples harbored a mutation and 16% (4) of BRAF harbored a mutation. Any mutation in these 3 oncogenes may induce the occurrence and development of breast cancer.

Peptide modified polymer poly (glycerol- dodecanedioate co-fumarate) for efficient control of motor neuron differentiation

Neural tissue engineering is one of the most promising approaches for healing nerve damage, which bypasses the limits of contemporary conventional treatments. In a previous study, we developed a fibrous scaffold via electrospinning poly (glycerol dodecanedioate) (PGD) and gelatin that mimics the structure of a native extracellular matrix (ECM) for soft tissue engineering application. In this study, fumaric acid (FA) was incorporated into the PGD synthesis process, which produced a PGD derivative referred to as poly (glycerol dodecanedioate co-fumarate) (PGDF). This introduced a new functional group, a double bond, into the polymer thus providing new modification possibilities. Arg-Gly-Asp-Cys (RGDC) and laminin peptides were chosen as biomolecules to modify the fiber and facilitate cell attachment and differentiation efficiency. The release of FA into the medium was quantified to investigate the bioreactivity of the derived scaffolds. In combination with UV crosslinking, the developed PGDF fiber mats were able to withstand degradation processes for up to 2 months, which ensures that neural tissue engineering applications are viable. Cell viability and motor neuron differentiation efficiency were demonstrated to be significantly improved with the addition of FA, RGDC and laminin peptides.

Observation of Fermi-Arc Spin Texture in TaAs

We have investigated the spin texture of surface Fermi arcs in the recently discovered Weyl semimetal TaAs using spin- and angle-resolved photoemission spectroscopy. The experimental results demonstrate that the Fermi arcs are spin polarized. The measured spin texture fulfills the requirement of mirror and time-reversal symmetries and is well reproduced by our first-principles calculations, which gives strong evidence for the topologically nontrivial Weyl semimetal state in TaAs. The consistency between the experimental and calculated results further confirms the distribution of chirality of the Weyl nodes determined by first-principles calculations.

A meta-analysis of erlotinib versus docetaxel for advanced nonsmall-cell lung cancer with poor prognosis

BACKGROUND

The extent of the benefit of erlotinib in the treatment of advanced nonsmall-cell lung cancer (NSCLC) is still controversial when compared with docetaxel. This meta-analysis was performed to compare the efficacy of erlotinib with docetaxel for different patients with advanced NSCLC.

MATERIALS AND METHODS

We searched Cochrane Library, PubMed, CNKI, and identified 23 randomized controlled clinical trials from 2008 to 2015. According to our further full-text screening, 6 clinical trials were included in the final meta-analysis.

RESULTS

Six papers were included in this study. The progression-free survival (PFS), overall survival (OS), objective response rate (ORR), and toxicity were included in our outcomes. The pooled hazard ratio (HR) of PFS was 1.57 (95% confidential index [CI] = 1.47-1.69). The pooled HR of OS was 1.66 (95% CI = 1.43-1.92). The pooled risk ratio of ORR was 0.56 (95% CI = 0.35-0.91). The toxicity analysis showed odds ratio = 1.79 (95% CI = 1.20-2.69).

CONCLUSIONS

In terms of PFS, OS, and toxicity the effect of erlotinib in the treatment of advanced NSCLC patients is superior to docetaxel.

Direct observation of the spin texture in SmB6 as evidence of the topological Kondo insulator

Topological Kondo insulators have been proposed as a new class of topological insulators in which non-trivial surface states reside in the bulk Kondo band gap at low temperature due to strong spin-orbit coupling. In contrast to other three-dimensional topological insulators, a topological Kondo insulator is truly bulk insulating. Furthermore, strong electron correlations are present in the system, which may interact with the novel topological phase. By applying spin- and angle-resolved photoemission spectroscopy, here we show that the surface states of SmB6 are spin polarized. The spin is locked to the crystal momentum, fulfilling time reversal and crystal symmetries. Our results provide strong evidence that SmB6 can host topological surface states in a bulk insulating gap stemming from the Kondo effect, which can serve as an ideal platform for investigating of the interplay between novel topological quantum states with emergent effects and competing orders induced by strongly correlated electrons.

A stable three-dimensional topological Dirac semimetal Cd3As2

Three-dimensional (3D) topological Dirac semimetals (TDSs) are a recently proposed state of quantum matter that have attracted increasing attention in physics and materials science. A 3D TDS is not only a bulk analogue of graphene; it also exhibits non-trivial topology in its electronic structure that shares similarities with topological insulators. Moreover, a TDS can potentially be driven into other exotic phases (such as Weyl semimetals, axion insulators and topological superconductors), making it a unique parent compound for the study of these states and the phase transitions between them. Here, by performing angle-resolved photoemission spectroscopy, we directly observe a pair of 3D Dirac fermions in Cd3As2, proving that it is a model 3D TDS. Compared with other 3D TDSs, for example, β-cristobalite BiO2 (ref. 3) and Na3Bi (refs 4, 5), Cd3As2 is stable and has much higher Fermi velocities. Furthermore, by in situ doping we have been able to tune its Fermi energy, making it a flexible platform for exploring exotic physical phenomena.

Superconductivity in topological insulator Sb2Te3 induced by pressure

Topological superconductivity is one of most fascinating properties of topological quantum matters that was theoretically proposed and can support Majorana Fermions at the edge state. Superconductivity was previously realized in a Cu-intercalated Bi₂Se₃ topological compound or a Bi₂Te₃ topological compound at high pressure. Here we report the discovery of superconductivity in the topological compound Sb₂Te₃ when pressure was applied. The crystal structure analysis results reveal that superconductivity at a low-pressure range occurs at the ambient phase. The Hall coefficient measurements indicate the change of p-type carriers at a low-pressure range within the ambient phase, into n-type at higher pressures, showing intimate relation to superconducting transition temperature. The first principle calculations based on experimental measurements of the crystal lattice show that Sb₂Te₃ retains its Dirac surface states within the low-pressure ambient phase where superconductivity was observed, which indicates a strong relationship between superconductivity and topology nature.

Electrospun fibrous scaffolds of Poly(glycerol-dodecanedioate) for engineering neural tissues from mouse embryonic stem cells

For tissue engineering applications, the preparation of biodegradable and biocompatible scaffolds is the most desirable but challenging task.  Among the various fabrication methods, electrospinning is the most attractive one due to its simplicity and versatility. Additionally, electrospun nanofibers mimic the size of natural extracellular matrix ensuring additional support for cell survival and growth. This study showed the viability of the fabrication of long fibers spanning a larger deposit area for a novel biodegradable and biocompatible polymer named poly(glycerol-dodecanoate) (PGD)(1) by using a newly designed collector for electrospinning. PGD exhibits unique elastic properties with similar mechanical properties to nerve tissues, thus it is suitable for neural tissue engineering applications. The synthesis and fabrication set-up for making fibrous scaffolding materials was simple, highly reproducible, and inexpensive. In biocompatibility testing, cells derived from mouse embryonic stem cells could adhere to and grow on the electrospun PGD fibers. In summary, this protocol provided a versatile fabrication method for making PGD electrospun fibers to support the growth of mouse embryonic stem cell derived neural lineage cells.

Complete mitochondrial genome sequence of Marmota himalayana (Rodentia: Sciuridae) and phylogenetic analysis within Rodentia

This is the first report of a complete mitochondrial genome sequence from Himalayan marmot (Marmota himalayana, class Marmota). We determined the M. himalayana mitochondrial (mt) genome sequence by using long-PCR methods and a primer-walking sequencing strategy with genus-specific primers. The complete mt genome of M. himalayana was 16,443 bp in length and comprised 13 protein-coding genes, 2 ribosomal RNA (rRNA) genes, 22 transfer RNA (tRNA) genes, and a typical control region (CR). Gene order and orientation were identical to those in mt genomes of most vertebrates. The heavy strand showed an overall A+T content of 63.49%. AT and GC skews for the mt genome of the M. himalayana were 0.012 and -0.300, respectively, indicating a nucleotide bias against T and G. The control region was 997 bp in size and displayed some unusual features, including absence of repeated motifs and two conserved sequence blocks (CSB2 and CSB3), which is consistent with observations from two other rodent species, Sciurus vulgaris and Myoxus glis. Phylogenetic analysis of complete mt DNA sequences without the control region including 30 taxa of Rodentia was performed with Maximum-Likelihood (ML) and Bayesian Inference (BI) methods and provided strong support for Sciurognathi polyphyly and Hystricognathi monophyly. This analysis also provided evidence that M. himalayana mt DNA was closely related to that from Sciurus vulgaris (Sciuridae) and was similar to mt DNA from Myoxus glis.

Estimating the effect of selected predictors on agricultural confined-space hazard perceptions of Utah farm owner/operators

The purpose of this study was to assess how selected variables affect the confined-space hazard perceptions of farmers in Utah. A confined space was defined as "any space found in an agricultural workplace that was not designed or intended as a regular workstation, has limited or restricted means of entry or exit, and contains potential physical and toxic hazards to workers who intentionally or unintentionally enter the space" (proposed by NCERA-197, 18 May 2011, draft copy). A total of 303 out of 327 farm owner/operators provided complete surveys that were used in the analysis. The state of Utah was grouped into five regions in this study: central, east, northeast, northwest, and southwest. Grain and dairy production comprised 48.7% of the operations responding to the survey. The general linear modeling (GLM) procedure in SAS 9.3 was used to select the models on hazard perception scores for the five studied regions. Interested predictors included response type, production type, safety planning, and injury concerns. Animal production operations had the highest average number of confined spaces (micro = 4, SD = 2.7). Regionally, the northwest region had the highest average number of confined spaces (micro = 4, SD = 2.5). The variables contributing most to confined-space hazard perceptions were injury and death concerns while working alone in confined spaces. Three factors were generated using principle factor analysis (PFA) with orthogonal varimax rotation. Results suggested that factors affect hazard perceptions differently by region. We conclude that outreach and educational efforts to change safety behaviors regarding confined-space hazards should be strategically targeted for each region based on predicting factors. The result can assist agricultural safety and health professionals in targeting agricultural producers' social networks to address human factors such as worker attitudes and/or lack of skills or knowledge that effect hazard perceptions of confined spaces in agriculture.