bluuebunny/crossref_metadata_2025_split huggingface dataset:
Silver nanoparticles and dissolved silver activate contrasting immune responses and stress-induced heat shock protein expression in sea urchin
Authors: Magesky Adriano , de Oliveira Ribeiro Ciro A. , Beaulieu Lucie , Pelletier Émilien 
Published: December 2016

Abstract

Using immune cells of sea urchin Strongylocentrotus droebachiensis in early development as a model, the cellular protective mechanisms against ionic and poly(allylamine)-coated silver nanoparticle (AgNPs; 14 ± 6 nm) treatments at 100 μg L−1 were investigated. Oxidative stress, heat shock protein expression, and pigment production by spherulocytes were determined as well as AgNP translocation pathways and their multiple effects on circulating coelomocytes. Sea urchins showed an increasing resilience to Ag over time because ionic Ag is accumulated in a steady way, although nanoAg levels dropped between 48 h and 96 h. A clotting reaction emerged on tissues injured by dissolved Ag (present as chloro-complexes in seawater) between 12 h and 48 h. Silver contamination and nutritional state influenced the production of reactive oxygen species. After passing through coelomic sinuses and gut, AgNPs were found in coelomocytes. Inside blood vessels, apoptosis-like processes appeared in coelomocytes highly contaminated by poly(allylamine)-coated AgNPs. Increasing levels of Ag accumulated by urchins once exposed to AgNPs pointed to a Trojan-horse mechanism operating over 12-d exposure. However, under short-term treatments, physical interactions of poly(allylamine)-coated AgNPs with cell structures might be, at some point, predominant and responsible for the highest levels of stress-related proteins detected. The present study is the first report detailing nano-translocation in a marine organism and multiple mechanisms by which sea urchin cells can deal with toxic AgNPs. Environ Toxicol Chem 2017;36:1872–1886. © 2016 SETAC
A review of ecological risk assessment methods for amphibians: Comparative assessment of testing methodologies and available data
Authors: Johnson Mark S , Aubee Catherine , Salice Christopher J , Leigh Katrina B , Liu Elissa , Pott Ute , Pillard David 
Published: December 2016

Abstract

Historically, ecological risk assessments have rarely included amphibian species, focusing preferentially on other aquatic (fish, invertebrates, algae) and terrestrial wildlife (birds and mammal) species. Often this lack of consideration is due to a paucity of toxicity data, significant variation in study design, uncertainty with regard to exposure, or a combination of all three. Productive risk assessments for amphibians are particularly challenging, given variations in complex life history strategies. Further consideration is needed for the development of useful laboratory animal models and appropriate experimental test procedures that can be effectively applied to the examination of biological response patterns. Using these standardized techniques, risk estimates can be more accurately defined to ensure adequate protection of amphibians from a variety of stress agents. Patterns in toxicity may help to ascertain whether test results from 1 amphibian group (e.g., Urodela) could be sufficiently protective of another (e.g., Anura) and/or whether some nonamphibian aquatic taxonomic groups (e.g., fish or aquatic invertebrates) may be representative of aquatic amphibian life stages. This scope is intended to be a guide in the development of methods that would yield data appropriate for ecological risk decisions applicable to amphibians. Integr Environ Assess Manag 2017;13:601–613. © 2016 SETAC

Key Points
Amphibians have complex life histories that add levels of complexity in the evaluation of risk at contaminated sites. Life histories for amphibians include exposures to contaminated water, soil, and potentially sediments. Aquatic surrogates (e.g., fish) are only partially useful in predicting effects to a single life stage for some amphibian species. More research is needed to understand the relative importance of exposure to terrestrial life stages in estimating risk.
Secretory phospholipase A2 in the pathogenesis of acute dengue infection
Authors: Jeewandara Chandima , Gomes Laksiri , Udari Sukhitha , Paranavitane S.A. , Shyamali N.L.A. , Ogg Graham S. , Malavige Gathsaurie Neelika 
Published: December 2016

AbstractIntroductionPlatelet activating factor (PAF) is an important mediator of vascular leak in acute dengue. Phospholipase A2s (PLA2) are inflammatory lipid enzymes that generate and regulate PAF and other mediators associated with mast cells. We sought to investigate if mast cell activation and increases in secretory sPLA2s are associated with an increase in PAF and occurrence of dengue haemorrhagic fever (DHF).MethodsThe changes in the levels of mast cell tryptase, PAF and the activity of sPLA2 were determined throughout the course of illness in 13 adult patients with DHF, and 30 patients with dengue fever (DF).ResultsWe found that sPLA2 activity was significantly higher in patients with DHF when compared to those with DF, during the first 120 h of clinical illness. sPLA2 activity was significantly associated with PAF levels, which were also significantly higher in patients with DHF. Although levels of mast cell tryptase were higher in patients with DHF, the difference was not significant, and the levels were not above the reference ranges. sPLA2 activity significantly correlated with the degree of viraemia in patients with DHF but not in those with DF.ConclusionsPLA2 appears to play an important role in the pathogenesis of dengue. Since its activity is significantly increased during the early phase of infection in patients with DHF, this suggests that understanding the underlying mechanisms may provide opportunities for early intervention.
Type 2 Diabetes Mellitus Is Associated With Better Bone Microarchitecture But Lower Bone Material Strength and Poorer Physical Function in Elderly Women: A Population-Based Study
Authors: Nilsson Anna G , Sundh Daniel , Johansson Lisa , Nilsson Martin , Mellström Dan , Rudäng Robert , Zoulakis Michail , Wallander Märit , Darelid Anna , Lorentzon Mattias 
Published: December 2016

ABSTRACT

Type 2 diabetes mellitus (T2DM) is associated with an increased risk of fractures according to several studies. The underlying mechanisms remain unclear, although small case-control studies indicate poor quality of the cortical bone. We have studied a population-based sample of women aged 75 to 80 years in Gothenburg, randomly invited from the population register. Areal bone mineral density (aBMD) was measured by dual-energy X-ray absorptiometry (Hologic Discovery A), bone microarchitecture by high-resolution peripheral quantitative computed tomography (HR-pQCT; ExtremeCT from Scanco Medical AG), and reference point indentation was performed with Osteoprobe (Active Life Scientific). Women with T2DM (n = 99) had higher aBMD compared to controls (n = 954). Ultradistal tibial and radial trabecular bone volume fraction (+11% and +15%, respectively), distal cortical volumetric BMD (+1.6% and +1.7%), cortical area (+11.5% and +9.3%), and failure load (+7.7% and +12.9%) were higher in diabetics than in controls. Cortical porosity was lower (mean ± SD: 1.5% ± 1.1% versus 2.0% ± 1.7%, p = 0.001) in T2DM in the distal radius but not in the ultradistal radius or the tibia. Adjustment for covariates (age, body mass index, glucocorticoid treatment, smoking, physical activity, calcium intake, bone-active drugs) eliminated the differences in aBMD but not in HR-pQCT bone variables. However, bone material strength index (BMSi) by reference point indentation was lower in T2DM (74.6 ± 7.6 versus 78.2 ± 7.5, p &lt; 0.01), also after adjustment, and women with T2DM performed clearly worse in measures of physical function (one leg standing: –26%, 30-s chair-stand test: –7%, timed up and go: +12%, walking speed: +8%; p &lt; 0.05-0.001) compared to controls. In conclusion, we observed a more favorable bone microarchitecture but no difference in adjusted aBMD in elderly women with T2DM in the population compared to nondiabetics. Reduced BMSi and impaired physical function may explain the increased fracture risk in T2DM. © 2016 American Society for Bone and Mineral Research.
BMI-1 Mediates Estrogen-Deficiency–Induced Bone Loss by Inhibiting Reactive Oxygen Species Accumulation and T Cell Activation
Authors: Li Jinbo , Wang Qian , Yang Renlei , Zhang Jiaqi , Li Xing , Zhou Xichao , Miao Dengshun 
Published: December 2016

ABSTRACT

Previous studies have shown that estrogen regulates bone homeostasis through regulatory effects on oxidative stress. However, it is unclear how estrogen deficiency triggers reactive oxygen species (ROS) accumulation. Recent studies provide evidence that the B lymphoma Mo-MLV insertion region 1 (BMI-1) plays a critical role in protection against oxidative stress and that this gene is directly regulated by estrogen via estrogen receptor (ER) at the transcriptional level. In this study, ovariectomized mice were given drinking water with/without antioxidant N-acetyl-cysteine (NAC, 1 mg/mL) supplementation, and compared with each other and with sham mice. Results showed that ovariectomy resulted in bone loss with increased osteoclast surface, increased ROS levels, T cell activation, and increased TNF and RANKL levels in serum and in CD4 T cells; NAC supplementation largely prevented these alterations. BMI-1 expression levels were dramatically downregulated in CD4 T cells from ovariectomized mice. We supplemented drinking water to BMI-1–deficient mice with/without NAC and compared them with each other and with wild-type (WT) mice. We found that BMI-1 deficiency mimicked alterations observed in ovariectomy whereas NAC supplementation reversed all alterations induced by BMI-1 deficiency. Because T cells are critical in mediating ovariectomy-induced bone loss, we further assessed whether BMI-1 overexpression in lymphocytes can protect against estrogen deficiency–induced osteoclastogenesis and bone loss by inhibiting oxidative stress, T cell activation, and RANKL production. When WT and Eμ-BMI-1 transgenic mice with BMI-1 specifically overexpressed in lymphocytes were ovariectomized and compared with each other and with WT sham mice, we found that BMI-1 overexpression in lymphocytes clearly reversed all alterations induced by ovariectomy. Results from this study indicate that estrogen deficiency downregulates BMI-1 and subsequently increases ROS, T cell activation, and RANKL production in T cells, thus enhancing osteoclastogenesis and accelerating bone loss. This study clarifies a novel mechanism regulating estrogen deficiency–induced bone loss. © 2016 American Society for Bone and Mineral Research.
Synoptic conditions during summertime temperature extremes in Alaska
Authors: Cassano Elizabeth N. , Cassano John J. , Seefeldt Mark W. , Gutowski William J. , Glisan Justin M. 
Published: December 2016

ABSTRACTThe atmospheric state and synoptic situation associated with widespread summer June, July, and August temperature extremes in southern Alaska is explored. Using ERA‐Interim data and a self‐organizing map framework, the evolution of the atmospheric state leading up to days that are defined as experiencing extreme surface temperature are compared with the evolution for non‐extreme days. The variables evaluated include circulation at the surface and aloft and surface radiative fluxes. For warm extremes, blocking evident in the 500 hPa flow combined with anomalously large surface downward shortwave radiation allowed surface temperatures to become extreme. For cold extremes, an upper level trough and cold air advection aloft coupled with a more minor role of anomalously negative surface downward shortwave radiation were important. The self‐organizing map framework allowed an investigation of these details beyond a composite analysis of all extremes.
Reversible Bioconjugation: Biodegradable Poly(phosphate)‐Protein Conjugates
Authors: Steinbach Tobias , Becker Greta , Spiegel Alina , Figueiredo Tamiris , Russo Daniela , Wurm Frederik R. 
Published: December 2016

AbstractProtein‐polymer conjugates are widely used to improve the pharmacokinetic properties of therapeutic proteins. Commercially available conjugates employ poly(ethylene glycol) (PEG) as the protective polymer; however, PEG has a number of shortcomings, including non‐biodegradability and immunogenicity, that call for the development of alternatives. Here, the synthesis of biodegradable poly(phosphate), that is, poly(ethyl ethylene phosphate) (PEEP), by organo‐catalyzed anionic ring‐opening polymerization exhibiting dispersity values Ð < 1.3 is reported. Polymers with molecular weights between 2000 and 33 200 g mol−1 are then ω‐functionalized with a succinimidyl carbonate group and subsequently conjugated to model proteins. These are the first conjugates based on polyphosphates which degraded upon exposure to phosphodiesterase. As is the case for PEGylated therapeutics, residual in vitro activity of the PPEylated conjugates depends on the extent of protein modification. These results suggest that PEEP exhibits the desired properties of a biopolymer for use in next generation, fully degradable drug delivery systems.
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Surface‐Initiated Atom Transfer Radical Polymerization from Electrospun Mats: An Alternative to Nafion
Authors: Javakhishvili Irakli , Dimitrov Ivaylo , Tynelius Oskar , Hales Jan , Jankova Katja , Hvilsted Søren 
Published: December 2016

Proton exchange membranes for fuel cell applications are synthesized by surface‐initiated (SI) atom transfer radical polymerization (ATRP). Poly(vinylidene fluoride‐co‐chlorotrifluoroethylene) is electrospun into 50 µm thick mat, which is then employed as multifunctional initiator for copper‐mediated SI ATRP of 4‐styrene sulfonic acid sodium salt. Fine‐tuning of the ATRP conditions allows adjustment of the membrane's ion exchange capacity by varying the loading of the grafted ionomer. Structure and composition of the membranes are investigated by spectroscopic means and thermogravimetric analysis, respectively. The membrane morphology is probed by scanning electron microscopy. A membrane with proton conductivity as high as 100 mS cm−1 is obtained. Long‐term durability study in direct methanol fuel cells is conducted for over 1500 h demonstrating the viability of this novel facile approach.
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A comprehensive meta‐analysis on dietary flavonoid and lignan intake and cancer risk: Level of evidence and limitations
Authors: Grosso Giuseppe , Godos Justyna , Lamuela‐Raventos Rosa , Ray Sumantra , Micek Agnieszka , Pajak Andrzej , Sciacca Salvatore , D'Orazio Nicolantonio , Del Rio Daniele , Galvano Fabio 
Published: December 2016

ScopeTo summarize available evidence on the association between dietary flavonoid as well as lignan intake and cancer risk in observational studies.Methods and resultsA systematic search on electronic databases of all English language case–control and prospective studies published up to June 2016 was performed. Risk ratios (RRs) and 95% confidence intervals were calculated by random‐effects model separately by study design. Heterogeneity and publication bias were tested. Out of the 143 studies included, meta‐analyses of prospective studies showed isoflavones significantly associated with decreased risk of lung and stomach cancers and nearly significant breast and colorectal cancers; total flavonoids showed nonsignificant decreased risk of breast cancer. Meta‐analyses of case–control studies showed: total and/or individual classes of flavonoids associated with upper aero‐digestive tract, colorectal, breast, and lung cancers; isoflavones with ovarian, breast, and colorectal cancers, endometrial and lung cancers.ConclusionsMost evidence reported in previous meta‐analyses was driven by case–control studies. Overall results may be promising but are inconclusive. Further prospective cohorts assessing dietary polyphenol exposure and studies using other methods to evaluate exposure (i.e. markers of consumption, metabolism, excretion) are needed to confirm and determine consumption levels required to achieve health benefits.
Quantitative proteomic profiling of paired cancerous and normal colon epithelial cells isolated freshly from colorectal cancer patients
Authors: Tu Chengjian , Mojica Wilfrido , Straubinger Robert M. , Li Jun , Shen Shichen , Qu Miao , Nie Lei , Roberts Rick , An Bo , Qu Jun 
Published: December 2016

PurposeThe heterogeneous structure in tumor tissues from colorectal cancer (CRC) patients excludes an informative comparison between tumors and adjacent normal tissues. Here, we develop and apply a strategy to compare paired cancerous (CEC) versus normal (NEC) epithelial cells enriched from patients and discover potential biomarkers and therapeutic targets for CRC.Experimental designCEC and NEC cells are respectively isolated from five different tumor and normal locations in the resected colon tissue from each patient (N = 12 patients) using an optimized epithelial cell adhesion molecule (EpCAM)‐based enrichment approach. An ion current‐based quantitative method is employed to perform comparative proteomic analysis for each patient.ResultsA total of 458 altered proteins that are common among >75% of patients are observed and selected for further investigation. Besides known findings such as deregulation of mitochondrial function, tricarboxylic acid cycle, and RNA post‐transcriptional modification, functional analysis further revealed RAN signaling pathway, small nucleolar ribonucleoproteins (snoRNPs), and infection by RNA viruses are altered in CEC cells. A selection of the altered proteins of interest is validated by immunohistochemistry analyses.Conclusion and clinical relevanceThe informative comparison between matched CEC and NEC enhances our understanding of molecular mechanisms of CRC development and provides biomarker candidates and new pathways for therapeutic intervention.
Cancer and inflammation
Authors: Munn Lance L. 
Published: December 2016

The relationship between inflammation and cancer has been recognized since the 17th century,1 and we now know much about the cells, cytokines and physiological processes that are central to both inflammation and cancer.2-9 Chronic inflammation can induce certain cancers,10-17 and solid tumors, in turn, can initiate and perpetuate local inflammatory processes that foster tumor growth and dissemination.5,18-20 Consequently, inflammatory pathways have been targeted in attempts to control cancer.21-23 Inflammation is a central aspect of the innate immune system's response to tissue damage or infection, and also facilitates the recruitment of circulating cells and antibodies of the adaptive immune response to the tissue. Components of the innate immune response carry out a robust, but sometimes overly‐conservative response, sacrificing specificity for the sake of preservation. Thus, when innate immunity goes awry, it can have profound implications. How the innate and adaptive immune systems cooperate to neutralize pathogens and repair damaged tissues is still an area of intense investigation. Further, how these systems can respond to cancer, which arises from normal ‘self’ cells that undergo an oncogenic transformation, has profound implications for cancer therapy. Recently, immunotherapies that activate adaptive immunity have shown unprecedented promise in the clinic, producing durable responses and dramatic increases in survival rate in patients with advanced stage melanoma.24-26 Consequently, the relationship between cancer and inflammation has now returned to the forefront of clinical oncology. WIREs Syst Biol Med 2017, 9:e1370. doi: 10.1002/wsbm.1370This article is categorized under:

Physiology > Mammalian Physiology in Health and Disease
Biological Mechanisms > Regulatory Biology
Geometrical shock dynamics for magnetohydrodynamic fast shocks
Authors: Mostert W. , Pullin D. I. , Samtaney R. , Wheatley V. 
Published: December 2016

We describe a formulation of two-dimensional geometrical shock dynamics (GSD) suitable for ideal magnetohydrodynamic (MHD) fast shocks under magnetic fields of general strength and orientation. The resulting area–Mach-number–shock-angle relation is then incorporated into a numerical method using pseudospectral differentiation. The MHD-GSD model is verified by comparison with results from nonlinear finite-volume solution of the complete ideal MHD equations applied to a shock implosion flow in the presence of an oblique and spatially varying magnetic field ahead of the shock. Results from application of the MHD-GSD equations to the stability of fast MHD shocks in two dimensions are presented. It is shown that the time to formation of triple points for both perturbed MHD and gas-dynamic shocks increases as $\unicode[STIX]{x1D716}^{-1}$, where $\unicode[STIX]{x1D716}$ is a measure of the initial Mach-number perturbation. Symmetry breaking in the MHD case is demonstrated. In cylindrical converging geometry, in the presence of an azimuthal field produced by a line current, the MHD shock behaves in the mean as in Pullin et al. (Phys. Fluids, vol. 26, 2014, 097103), but suffers a greater relative pressure fluctuation along the shock than the gas-dynamic shock.
Power Law of Critical Buckling in Structural Members Supported by a Winkler Foundation
Authors: Sato M. , Harasawa S. , Konishi Y. , Maruyama T. , Park S. J. 
Published: December 2016

AbstractIn the fields of engineering, nanoscience, and biomechanics, thin structural members, such as beams, plates, and shells, that are supported by an elastic medium are used in several applications. There is a possibility that these thin structures might buckle under severe loading conditions; higher-order, complicated elastic buckling modes can be found owing to the balance of rigidities between the thin members and elastic supports. In this study, we have shown a new and simple ‘power law’ relation between the critical buckling strain (or loads) and rigidity parameters in structural members supported by an elastic medium, which can be modelled as a Winkler foundation. The following structural members have been considered in this paper: i) a slender beam held by an outer elastic support under axial loading, ii) cylindrical shells supported by an inner elastic core under hydrostatic pressure (plane strain condition), and iii) complete spherical shells that are filled with an inner elastic medium.
Increased GABAA receptor binding in amygdala after prenatal administration of valproic acid to rats
Authors: Bertelsen Freja , Møller Arne , Folloni Davide , Drasbek Kim Ryun , Scheel-Krüger Jørgen , Landau Anne M. 
Published: December 2016

ObjectivePrenatal exposure to valproic acid (VPA) enhances the risk for later development of autism spectrum disorders (ASD). An altered gamma-aminobutyric acid (GABA) system may be a key factor in ASD. Here we investigated possible changes in the GABA system in rats exposed to a low dose of prenatal VPA.MethodWe performed autoradiography with [3H]muscimol, (a GABAA receptor agonist), and [11C]Ro15-4513 (a partial agonist of the GABAA α1+5 receptor subtypes), in brain sections containing amygdala, thalamus and hippocampus of rats treated prenatally with 20 mg/kg VPA or saline from the 12th day of gestation.ResultPrenatal VPA significantly increased [11C]Ro15-4513 binding in the left amygdala compared with controls (p<0.05). This difference was not observed in the hippocampus, thalamus or right amygdala. No differences were observed in [3H]muscimol binding.ConclusionWe observed an asymmetric increase in GABAA receptor binding. Disturbances in the GABAA receptor system have also been detected in human autism with [11C]Ro15-4513.