Comprehensive approach to national tire wear emissions: Challenges and implications

The use of vehicle tires has been identified as a major source of microplastics in the environment and an increasing source of urban particulate air pollution. In light of increasing traffic volumes, increasingly heavier and more powerful vehicles due to trends and electrification, and the lack of tire wear regulation, methods to estimate and monitor changes in national emissions are needed as input for environmental impact assessments. Emission estimations of tire wear are made either based on the mileage approach or the sales approach. This study aims to investigate if and how the mileage approach can be improved by using emission factors for passenger cars and LDVs based on our own measurements and emission factors from the literature for HDVs and buses. An approach with emission factor adjustments based on weight and number of tires in combination with highly detailed mileage data has been evaluated. Sales approach calculations have been used to validate the method. A secondary aim was to use the new mileage approach framework to calculate the national tire wear emissions for Sweden. These calculations resulted in slightly lower total emissions than previous estimations provide, but with higher emissions for passenger cars and light-duty vehicles, and lower emissions for heavy-duty vehicles and motorcycles. Passenger cars constitute more than half of the total emissions. It is concluded that even though the framework offers greater detail, thus increasing the possibilities to adjust for changes in emission factors and mileages in specific vehicle categories, the challenges posed by such factors as the lack of measured emission factors for heavy-duty vehicles and uncertainties regarding the quality of mileage statistics makes the estimations uncertain. Important future suggestions for research include establishing reliable emission factors, especially for heavy-duty vehicles, and initiating research to better understand how climate, road networks, surface properties, and vehicle fleet characteristics affect emission factors.

Airway contraction and cytokine release in isolated rat lungs induced by wear particles from the road and tire interface and road vehicle brakes

The dominant road traffic particle sources are wear particles from the road and tire interface, and from vehicle brake pads. The aim of this work was to investigate the effect of road and brake wear particles on pulmonary function and biomarkers in isolated perfused rat lungs. Particles were sampled from the studded tire wear of three road pavements containing different rock materials in a road simulator; and from the wear of two brake pad materials using a pin-on-disk machine. Isolated rat lungs inhaled the coarse and fine fractions of the sampled particles resulting in an estimated total particle lung dose of 50 μg. The tidal volume (TV) was measured during the particle exposure and the following 50 min. Perfusate and BALF were analyzed for the cytokines TNF, CXCL1 and CCL3. The TV of lungs exposed to rock materials was significantly reduced after 25 min of exposure compared to the controls, for quartzite already after 4 min. The particles of the heavy-duty brake pads had no effect on the TV. Brake particles resulted in a significant elevation of CXCL1 in the perfusate. Brake particles showed significant elevations of all three measured cytokines, and quartzite showed a significant elevation of TNF in BALF. The study shows that the toxic effect on lungs exposed to airborne particles can be investigated using measurements of tidal volume. Furthermore, the study shows that the choice of rock material in road pavements has the potential to affect the toxicity of road wear PM10.

Upper bounds on focusing efficiency

Upper bounds on the focusing efficiency of aperture fields and lens systems are formulated using integral equation representations of Maxwell's equations and Lagrangian duality. Two forms of focusing efficiency are considered based on lens exit plane fields and optimal polarization currents within lens design regions of prescribed shape and available materials. Bounds are compared against the performance of classical prescriptions of ideal lens aperture fields, hyperbolic lens designs, and lenses produced by inverse design. Results demonstrate that, without regularization, focusing efficiency based solely on lens exit plane fields is unbounded, similar to the problem of unbounded antenna directivity. Additionally, results considering extruded two-dimensional dielectric geometries driven by out-of-plane electric fields for the calculation of bounds and inverse design demonstrate that aperture fields based on time-reversal do not necessarily yield optimal lens focusing efficiency, particularly in the case of near-field (high numerical aperture) focusing.

Concentrations of tire wear microplastics and other traffic-derived non-exhaust particles in the road environment

Tire wear particles (TWP) are assumed to be one of the major sources of microplastic pollution to the environment. However, many of the previously published studies are based on theoretical estimations rather than field measurements. To increase the knowledge regarding actual environmental concentrations, samples were collected and analyzed from different matrices in a rural highway environment to characterize and quantify TWP and other traffic-derived non-exhaust particles. The sampled matrices included road dust (from kerb and in-between wheeltracks), runoff (water and sediment), and air. In addition, airborne deposition was determined in a transect with increasing distance from the road. Two sieved size fractions (2-20 µm and 20-125 µm) were analyzed by automated Scanning Electron Microscopy/Energy Dispersive X-ray spectroscopy (SEM/EDX) single particle analysis and classified with a machine learning algorithm into the following subclasses: TWP, bitumen wear particles (BiWP), road markings, reflecting glass beads, metals, minerals, and biogenic/organic particles. The relative particle number concentrations (%) showed that the runoff contained the highest proportion of TWP (up to 38 %). The share of TWP in kerb samples tended to be higher than BiWP. However, a seasonal increase of BiWP was observed in coarse (20-125 µm) kerb samples during winter, most likely reflecting studded tire use. The concentration of the particle subclasses within airborne PM_80-1 decreases with increasing distance from the road, evidencing road traffic as the main emission source. The results confirm that road dust and the surrounding environment contain traffic-derived microplastics in both size fractions. The finer fraction (2-20 µm) dominated (by mass, volume, and number) in all sample matrices. These particles have a high potential to be transported in water and air far away from the source and can contribute to the inhalable particle fraction (PM₁₀) in air. This highlights the importance of including also finer particle fractions in future investigations.

A Review of Road Traffic-Derived Non-Exhaust Particles: Emissions, Physicochemical Characteristics, Health Risks, and Mitigation Measures

Implementation of regulatory standards has reduced exhaust emissions of particulate matter from road traffic substantially in the developed world. However, nonexhaust particle emissions arising from the wear of brakes, tires, and the road surface, together with the resuspension of road dust, are unregulated and exceed exhaust emissions in many jurisdictions. While knowledge of the sources of nonexhaust particles is fairly good, source-specific measurements of airborne concentrations are few, and studies of the toxicology and epidemiology do not give a clear picture of the health risk posed. This paper reviews the current state of knowledge, with a strong focus on health-related research, highlighting areas where further research is an essential prerequisite for developing focused policy responses to nonexhaust particles.

Fundamental bounds on the performance of monochromatic passive cloaks

Fundamental bounds on the performance of monochromatic scattering-cancellation and field-zeroing cloaks made of prescribed linear passive materials occupying a predefined design region are formulated by projecting field quantities onto a sub-sectional basis and applying quadratically constrained quadratic programming. Formulations are numerically tested revealing key physical trends as well as advantages and disadvantages between the two classes of cloaks. Results show that the use of low-loss materials with high dielectric contrast affords the highest potential for effective cloaking.

Traffic-related microplastic particles, metals, and organic pollutants in an urban area under reconstruction

In urban environments, particularly areas under reconstruction, metals, organic pollutants (OP), and microplastics (MP), are released in large amounts due to heavy traffic. Road runoff, a major transport route for urban pollutants, contributes significantly to a deteriorated water quality in receiving waters. This study was conducted in Gothenburg, Sweden, and is unique because it simultaneously investigates the occurrence of OP, metals, and MP on roads and in stormwater from an urban area under reconstruction. Correlations between the various pollutants were also explored. The study was carried out by collecting washwater and sweepsand generated from street sweeping, road surface sampling, and flow-proportional stormwater sampling on several occasions. The liquid and solid samples were analyzed for metals, polycyclic aromatic hydrocarbons (PAH), oxy-PAH, aliphatics, aromatics, phthalates, and MP. The occurrence of OP was also analyzed with a non-target screening method of selected samples. Microplastics, i.e. plastic fragments/fibers, paint fragments, tire wear particles (TWP) and bitumen, were analyzed with a method based on density separation with sodium iodide and identification with a stereo microscope, melt-tests, and tactile identification. MP concentrations amounted to 1500 particles/L in stormwater, 51,000 particles/L in washwater, and 2.6 × 10⁶ particles/kg dw in sweepsand. In stormwater, washwater and sweepsand, MP ≥20 μm were found to be dominated by TWP (38%, 83% and 78%, respectively). The results confirm traffic as an important source to MP, OP, and metal emissions. Concentrations exceeding water and sediment quality guidelines for metals (e.g. Cu and Zn), PAH, phthalates, and aliphatic hydrocarbons in the C₁₆-C₃₅ fraction were found in most samples. The results show that the street sweeper collects large amounts of polluted materials and thereby prevents further spread of the pollutants to the receiving stormwater.

Parents' experiences of participating in health-promoting activities at a family centre for preschool children in Sweden

In Sweden, the family centre is a meeting place for families in a neighbourhood. It is a place for families to meet and exchange experiences and is a confidence-filled place for preschool children to play and develop. The staff at the family centre collaborate on early prevention strategies to promote health. Since 2014, the Public Dental Health Service in Södra Ryd, Skövde, has been a collaborative partner with the family centre.

OBJECTIVES

To explore and describe the parents' experiences of participating in health-promoting activities at the family centre.

BASIC RESEARCH DESIGN

A qualitative design based on interviews, analysed using a phenomenograpic approach.

PARTICIPANTS

Six focus groups with two to six participants in each group.

RESULTS

Three themes, all describing parents' experiences of visiting the family centre, emerged in the analysis. The themes were as follows; "Social fellowship", "A secure place" and "A learning environment". Each theme contained three categories, which represent the parents' different conceptions.

CONCLUSIONS

The present study showed that the parents who visit the family centre found that the collaboration is perceived as positive and has many benefits. The participants found that the family centre is an institution that increases social interaction. Furthermore, meeting dental professionals in an arena outside the clinic creates confidence and makes people feel secure. Parents also learn both from the staff and from each other. According to these findings, the family centre is a suitable arena to work on health-promotion activities.

Trade-offs in absorption and scattering by nanophotonic structures

Trade-offs between absorption and scattering cross sections of lossy obstacles confined to an arbitrarily shaped volume are formulated as a multi-objective optimization problem solvable by Lagrangian-dual methods. Solutions to this optimization problem yield a Pareto-optimal set, the shape of which reveals the feasibility of achieving simultaneously extremal absorption and scattering. Two forms of the trade-off problems are considered involving both pre-assigned loss and reactive material parameters. Numerical comparisons between the derived multi-objective bounds and several classes of realized structures are made. Additionally, low-frequency (electrically small, long wavelength) limits are examined for certain special cases.

Occurrence of tire and bitumen wear microplastics on urban streets and in sweepsand and washwater

Tire and road wear particles have been identified as a potential major source of microplastics in the environment. However, more knowledge of the emissions and their further fate in the environment is needed, and the effectiveness and benefits of potential measures must be investigated to support future risk management efforts. Here the concentrations of tire and bitumen microplastic particles (TBMP) on roads and in nearby in stormwater, sweepsand and washwater were measured for the first time within the same area and time period. The analysis also included plastic, paint and fiber particles. Road dust was sampled on the road surface using a wet dust sampler, before and after street sweeping on two occasions. On each of these occasions, and several occasions during a four-month period with frequent street sweeping, sweepsand and washwater, as well as flow-weighted sampling of stormwater, were collected. TBMP concentrations were operationally defined, using density separation for some samples, followed by analysis by stereo microscopy. Sodium iodide (NaI) was found to be effective for density separation of TBMP. The largest proportion of anthropogenic microplastics detected consisted of tire tread wear and bitumen. The number of TBMP ≥100 μm in the WDS samples was up to 2561 particles/L. Sweepsand and washwater contained high amounts of TBMP ≥100 μm, up to 2170 particles/kg dw and 4500 particles/L, respectively. The results show that the sweeper collects considerable amounts of TBMP, and thus weekly sweeping might prevent further transport of TBMP to the receiving stormwater. In stormwater the number of particles ≥100 μm was up to 3 particles/L and ≥ 20 μm was up to 5900 particles/L showing the importance of analysing smaller microparticle sizes than 100 μm in all samples in future studies. This study also confirms that there is a substantial volume of TBMP generated from traffic that enters the environment.

Organic pollutants, nano- and microparticles in street sweeping road dust and washwater

Road areas are pollution hotspots where many metals, organic pollutants (OPs) and nano/microparticles accumulate before being transported to receiving waters. Particles on roads originate from e.g. road, tyre and vehicle wear, winter road maintenance, soil erosion, and deposition. Street sweeping has the potential to be an effective and affordable practice to reduce the occurrence of road dust, and thereby the subsequent spreading of pollutants, but there is currently little knowledge regarding its effectiveness. In this paper we investigate the potential of street sweeping to reduce the amounts of OPs and nano/microparticles reaching stormwater, in a case study sampling road dust and washwater from a street sweeping machine, road dust before and after sweeping, and stormwater. The compound groups generally found in the highest concentrations in all matrices were aliphatics C₅-C₃₅ > phthalates > aromatics C₈-C₃₅ > PAH-16. The concentrations of aliphatics C₁₆-C₃₅ and PAHs in washwater were extremely high at ≤ 53,000 µg/L and ≤ 120 µg/L, respectively, and the highest concentrations were found after a 3-month winter break in sweeping. In general, fewer aliphatic and aromatic petroleum hydrocarbons and PAHs were detected in road dust samples than in washwater. The relative composition of the specific PAH-16 suggests tyre wear, vehicle exhausts, brake linings, motor oils and road surface wear as possible sources. The study indicates that many of the hydrophobic compounds quantified in washwater are attached to small particles or truly dissolved. The washwater contains a wide range of small particles, including nanoparticles in sizes from just below 1 nm up to 300 nm, with nanoparticles in the size range 25-300 nm present in the highest concentrations. The results also indicated agglomeration of nanoparticles in the washwater. The street sweeping collected a large amount of fine particles and associated pollutants, leading to the conclusion that washwater from street sweeping needs to be treated before disposal.

Quasi-Herglotz functions and convex optimization

We introduce the set of quasi-Herglotz functions and demonstrate that it has properties useful in the modelling of non-passive systems. The linear space of quasi-Herglotz functions constitutes a natural extension of the convex cone of Herglotz functions. It consists of differences of Herglotz functions and we show that several of the important properties and modelling perspectives are inherited by the new set of quasi-Herglotz functions. In particular, this applies to their integral representations, the associated integral identities or sum rules (with adequate additional assumptions), their boundary values on the real axis and the associated approximation theory. Numerical examples are included to demonstrate the modelling of a non-passive gain medium formulated as a convex optimization problem, where the generating measure is modelled by using a finite expansion of B-splines and point masses.

Optical theorems and physical bounds on absorption in lossy media

Two different versions of an optical theorem for a scattering body embedded inside a lossy background medium are derived in this paper. The corresponding fundamental upper bounds on absorption are then obtained in closed form by elementary optimization techniques. The first version is formulated in terms of polarization currents (or equivalent currents) inside the scatterer and generalizes previous results given for a lossless medium. The corresponding bound is referred to here as a variational bound and is valid for an arbitrary geometry with a given material property. The second version is formulated in terms of the T-matrix parameters of an arbitrary linear scatterer circumscribed by a spherical volume and gives a new fundamental upper bound on the total absorption of an inclusion with an arbitrary material property (including general bianisotropic materials). The two bounds are fundamentally different as they are based on different assumptions regarding the structure and the material property. Numerical examples including homogeneous and layered (core-shell) spheres are given to demonstrate that the two bounds provide complimentary information in a given scattering problem.

Inhalation toxicity profiles of particulate matter: a comparison between brake wear with other sources of emission

Objective: There is substantial evidence that exposure to airborne particulate matter (PM) from road traffic is associated with adverse health outcomes. Although it is often assumed to be caused by vehicle exhaust emissions such as soot, other components may also contribute to detrimental effects. The toxicity of fine PM (PM2.5; <2.5 µm mass median aerodynamic diameter) released from brake pads was compared to PM from other sources. Materials and methods: PM2.5 of different types of brake pads (low-metallic, semi-metallic, NAO and ECE-NAO hybrid), tires and road pavement, poultry as well as the combustion of diesel fuel and wood (modern and old-fashioned stove technologies) were collected as suspensions in water. These were subsequently aerosolized for inhalation exposures. Female BALB/cOlaHsd mice were exposed for 1.5, 3, or 6 hours by nose-only inhalation up to 9 mg/m³. Results: Neither cytotoxicity nor oxidative stress was observed after exposure to any of the re-aerosolized PM2.5 samples. Though, at similar PM mass concentrations the potency to induce inflammatory responses was strongly dependent on the emission source. Exposure to most examined PM2.5 sources provoked inflammation including those derived from the poultry farm, wear emissions of the NAO and ECE-NAO hybrid brake pads as well as diesel and wood combustion, as indicated by neutrophil chemoattractant, KC and MIP-2 and lung neutrophil influx. Discussion and conclusions: Our study revealed considerable variability in the toxic potency of brake wear particles. Understanding of sources that are most harmful to health can provide valuable information for risk management strategies and could help decision-makers to develop more targeted air pollution regulation.

Abstract 4175: Targeting of a mesenchymal profile in order to sensitize multitherapy resistant glioblastoma clones

The overall aim of this study was to find ways to sensitize treatment resistant glioma-initiating cell (GIC) clones to conventional therapy. Heterogeneity is substantial in glioblastoma multiforme (GBM) and through establishment of clonal GIC cultures from patient biopsies we have demonstrated a wide variety in the responses to drugs and radiation. A multitherapy resistance phenotype was linked to proneural-mesenchymal transition (PMT) in the transcriptome. The variety in therapy response was observed as a continuum of phenotypes. The distribution of phenotypes resembled a normal distribution and multitherapy resistance was associated with low DNA methylation grade in promoter regions of mesenchymal master regulators (FOSL2, RUNX1). Our data thus implied that the transition is bi-directional and epigenetically regulated (Segerman et al, Cell Reports - accepted in principle).

To investigate if spontaneous changes in drug and radiation response occur, we have derived subclones from a resistant clone. Both subclones with higher and lower therapy resistance than the parental clone were generated. Also molecularly the subclones largely reconstituted the original clonal variation.

PMT shows similarities to epithelial-mesenchymal transition (EMT), which is induced by extrinsic factors. We therefore specifically analyzed the gene expression data for signaling receptors differentially expressed in resistant vs. sensitive clones as well as cognate ligands. To estimate the importance of a particular signaling pathway, expression of co-receptors and ligands was taken into account. We found several cases of coherent upregulation of receptor and ligand indicative of autocrine loops. Regarding pathways that appeared to be overactive in resistant vs. sensitive clones, there was a prominent overlap with EMT. It was also apparent that several pathways were activated concomitantly.

We are currently focusing on identifying combinations of drugs (and antibodies) that sensitize resistant clones to conventional treatment through modulation of cell signaling patterns. In the initial screen temozolomide (TMZ) response is used as an indicator of achieved sensitization. The strategy is to iteratively combine primarily antagonists of signaling receptors connected to resistance. We are also exploring the effect of stimulating pathways with apparently higher activity in sensitive clones (e.g. addition of ligands).The concept of sensitizing glioma and other types of cancer cells by targeting the mesenchymal character through usage of e.g. signaling receptor inhibitors is not new and has shown promise. Indeed, our preliminary data look encouraging.

In conclusion, our data show that multitherapy resistance is connected to a plastic cell-state. Also, receptors and ligands that are differentially expressed in resistant and sensitive clones engage pathways regulating EMT.

Citation Format: Mia Niklasson, Malin Jarvius, Caroline Haglund, Efthymia Chantzi, Tobias Bergström, Frida Nyberg, Annika Hermansson, Mårten Fryknäs, Mats Gustafsson, Bo Segerman, Rolf Larsson, Bengt Westermark, Anna Segerman. Targeting of a mesenchymal profile in order to sensitize multitherapy resistant glioblastoma clones [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4175. doi:10.1158/1538-7445.AM2017-4175

Mass spectrometry based metabolomics for in vitro systems pharmacology: pitfalls, challenges, and computational solutions

INTRODUCTION

Mass spectrometry based metabolomics has become a promising complement and alternative to transcriptomics and proteomics in many fields including in vitro systems pharmacology. Despite several merits, metabolomics based on liquid chromatography mass spectrometry (LC-MS) is a developing area that is yet attached to several pitfalls and challenges. To reach a level of high reliability and robustness, these issues need to be tackled by implementation of refined experimental and computational protocols.

OBJECTIVES

This study illustrates some key pitfalls in LC-MS based metabolomics and introduces an automated computational procedure to compensate for them.

METHOD

Non-cancerous mammary gland derived cells were exposed to 27 chemicals from four pharmacological classes plus a set of six pesticides. Changes in the metabolome of cell lysates were assessed after 24 h using LC-MS. A data processing pipeline was established and evaluated to handle issues including contaminants, carry over effects, intensity decay and inherent methodology variability and biases. A key component in this pipeline is a latent variable method called OOS-DA (optimal orthonormal system for discriminant analysis), being theoretically more easily motivated than PLS-DA in this context, as it is rooted in pattern classification rather than regression modeling.

RESULT

The pipeline is shown to reduce experimental variability/biases and is used to confirm that LC-MS spectra hold drug class specific information.

CONCLUSION

LC-MS based metabolomics is a promising methodology, but comes with pitfalls and challenges. Key difficulties can be largely overcome by means of a computational procedure of the kind introduced and demonstrated here. The pipeline is freely available on www.github.com/stephanieherman/MS-data-processing.

Novel Genetic Variants in BAG3 and TNNT2 in a Swedish Family with a History of Dilated Cardiomyopathy and Sudden Cardiac Death

Familial dilated cardiomyopathy is a rare cause of dilated cardiomyopathy (DCM), especially in childhood. Our aim was to describe the clinical course and the genetic variants in a family where the proband was a four-month-old infant presenting with respiratory problems due to DCM. In the family, there was a strong family history of DCM and sudden cardiac death in four generations. DNA was analyzed initially from the deceased girl using next-generation sequencing including 50 genes involved in cardiomyopathy. A cascade family screening was performed in the family after identification of the TNNT2 and the BAG3 variants in the proband. The first-degree relatives underwent clinical examination including biochemistry panel, cardiac ultrasound, Holter ECG, exercise stress test, and targeted genetic testing. The index patient presented with advanced DCM. After a severe clinical course, the baby had external left ventricular assist as a bridge to heart transplantation. 1.5 months after transplantation, the baby suffered sudden cardiac death (SCD) despite maximal treatment in the pediatric intensive care unit. The patient was shown to carry two heterozygous genetic variants in the TNNT2 gene [TNNT2 c.518G>A(p.Arg173Gln)] and BAG3 [BAG3 c.785C>T(p.Ala262Val)]. Two of the screened individuals (two females) appeared to carry both the familial variants. All the individuals carrying the TNNT2 variant presented with DCM, the two adult patients had mild or moderate symptoms of heart failure and reported palpitations but no syncope or presyncopal attacks prior to the genetic diagnosis. The female carriers of TNNT2 and BAG3 variants had more advanced DCM. In the family history, there were three additional cases of SCD due to DCM, diagnosed by autopsy, but no genetic analysis was possible in these cases. Our findings suggest that the variants in TNNT2 and BAG3 are associated with a high propensity to life-threatening cardiomyopathy presenting from childhood and young adulthood.

Abstract 213: Mitochondrial inhibitors and statins: a lethal combination for metabolically stressed cancer cells

Inhibition of mitochondrial oxidative phosphorylation (OXPHOS) has recently emerged as a promising strategy for treatment of therapy-resistant cancer cells. These cells often reside within hypoxic tumor regions, where nutrient concentrations are low. Recently, OXPHOS inhibitors have been demonstrated to be toxic to quiescent, nutrient-deprived cells in multicellular tumor spheroids. Such spheroids, formed without medium exchange over the culture period, can serve as an appropriate model to mimic quiescent in vivo tumor regions. These spheroids exhibit low cell proliferation and comprise necrotic cores, contrary to commonly used spheroids cultured with frequent medium change.

We here aimed to characterize how quiescent cells respond to OXPHOS inhibition and thereby identify processes that could be co-targeted for enhanced toxicity. We treated HCT116 colon cancer cell line, grown as monolayer cultures and spheroids, with a range of OXPHOS inhibitors (n = 10, including FDA-approved drugs, e.g. nitazoxanide) and other compounds (n = 14) at escalating doses and in 4 biological replicates. Then, we obtained global gene expression profiles (n = 1149, including 144 vehicle controls) of all treatment conditions using L1000 Gene Expression Profiling method.

We found that upon exposure to OXPHOS inhibitors cells grown as nutrient-deprived spheroids significantly and in dose-dependent manner upregulate expression of genes involved in biosynthesis of cholesterol. This response was not observed for spheroids cultured with medium change or monolayer cell cultures. Thus, we were interested if simultaneous exposure to OXPHOS inhibitors and statins, inhibitors of mevalonate (cholesterol precursor) synthesis, would result in enhanced cytotoxic effects in quiescent, metabolically stressed cells.

We here demonstrate that combination of OXPHOS inhibitors and statins results in pronounced synergistic cytotoxicity in metabolically stressed spheroids. This effect was observed for various classes of OXPHOS inhibitors and different types of statins, indicating that the observed synergy was not a result of off-target effects. This notion was further strengthened by the finding that mevalonate largely abrogated the synergistic effects.

In conclusion, we here report that statins enhance the toxic effects of OXPHOS inhibitors in quiescent, metabolically stressed cells. Our results can serve as a foundation for further studies on targeting therapy-resistant and nutrient-deprived cancer cells by inhibition of OXPHOS. We also demonstrate, for the first time, that the L1000 Gene Expression Profiling can be used to study 3D cell cultures. Importantly, our findings underscore the importance of using a relevant cellular model for target discovery endeavors.

Citation Format: Wojciech Senkowski, Malin Jarvius, Kim Kultima, Jenny Rubin, Mats Gustafsson, Peter Nygren, Rolf Larsson, Mårten Fryknäs. Mitochondrial inhibitors and statins: a lethal combination for metabolically stressed cancer cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 213.

Abstract 2415: GBM exhibits phenotypic microheterogeneity and harbors pre-existing multi- resistant clones with a mesenchymal transition signature

Glioblastoma multiforme (GBM) remains in the group of incurable malignancies, with a median survival of 15 months. Intratumoral heterogeneity is a key factor driving relapse by providing the basis for escape of therapy-resistant cells. While the heterogeneous genomic and transcriptomic landscape of cancers is currently thoroughly characterized, phenotypic heterogeneity within tumors is less well understood. The overall goal in this study was to identify pre-existing treatment resistant clones with disease relapse potential and biomarkers linked to resistance vs sensitivity. To enable functional studies of isolated tumor clones we adopted an in vitro subcloning strategy. An adherent glioma neural stem cell culturing protocol was used to enrich for cells with stem-like properties and to permit efficient phenotypic screening.

We established six libraries of clonal cell cultures from fresh GBM surgical specimens, corresponding to five different patient tumors. In all 708 clonal cultures were expanded. These were considered representatives of the self-renewing compartment within the tumor cell population. We found a remarkable variation in drug and radiation response within the clone libraries. A striking observation was that clones resistant to one drug, also tended to be resistant to most of the drugs we used, regardless of the drug's mechanism of action. This indicates that resistance in large parts is mediated by a general mechanism.

Most clones carried genetic aberrations that were unique or found only in a few clones but it was primarily the transcriptome data that demonstrated a clear link to the phenotypic data.

A continuous gradient between multi-resistance and sensitivity was found to be connected to a gradual transition between a mesenchymal (MES), in resistant clones, and a more proneural (PN) and proliferative character in sensitive clones. The continuous distributions and lack of discrete groups in clonal response phenotypes and in linked signatures points to a general cell-state related resistance mechanism.

We also found that resistant clones had a lower methylation level in promoters of known master regulators of MES subtype associated genes. This indicates that the phenotypic heterogeneity is driven by fluctuations in the epigenetic status.

Taken together, our findings imply that intratumoral heterogeneity in GBM includes general clonal resistance mechanisms among glioma- initiating cells driven by epigenetic mechanisms. This evokes hope that new therapeutic approaches involving epigenetic reprogramming can be applied to sensitize cells toward conventional treatment.

Citation Format: Anna Segerman, Maria Niklasson, Caroline Haglund, Tobias Bergstrom, Malin Jarvius, Yuan Xie, Demet Caglayan Simov, Annika Hermansson, Marianne Kastemar, Zeinab Naimaie-Ali, Malin Berglund, Ann Westermark, Magnus Sundstrom, Goran Hesselager, Lene Uhrbom, Mats Gustafsson, Rolf Larsson, Marten Fryknas, Bo Segerman, Bengt Westermark. GBM exhibits phenotypic microheterogeneity and harbors pre-existing multi- resistant clones with a mesenchymal transition signature. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2415.

Searching for Dark Matter Annihilation from Milky Way Dwarf Spheroidal Galaxies with Six Years of Fermi Large Area Telescope Data

The dwarf spheroidal satellite galaxies (dSphs) of the Milky Way are some of the most dark matter (DM) dominated objects known. We report on γ-ray observations of Milky Way dSphs based on six years of Fermi Large Area Telescope data processed with the new Pass8 event-level analysis. None of the dSphs are significantly detected in γ rays, and we present upper limits on the DM annihilation cross section from a combined analysis of 15 dSphs. These constraints are among the strongest and most robust to date and lie below the canonical thermal relic cross section for DM of mass ≲100  GeV annihilating via quark and τ-lepton channels.

Three-Dimensional Cell Culture-Based Screening Identifies the Anthelmintic Drug Nitazoxanide as a Candidate for Treatment of Colorectal Cancer

Because dormant cancer cells in hypoxic and nutrient-deprived regions of solid tumors provide a major obstacle to treatment, compounds targeting those cells might have clinical benefits. Here, we describe a high-throughput drug screening approach, using glucose-deprived multicellular tumor spheroids (MCTS) with inner hypoxia, to identify compounds that specifically target this cell population. We used a concept of drug repositioning-using known molecules for new indications. This is a promising strategy to identify molecules for rapid clinical advancement. By screening 1,600 compounds with documented clinical history, we aimed to identify candidates with unforeseen potential for repositioning as anticancer drugs. Our screen identified five molecules with pronounced MCTS-selective activity: nitazoxanide, niclosamide, closantel, pyrvinium pamoate, and salinomycin. Herein, we show that all five compounds inhibit mitochondrial respiration. This suggests that cancer cells in low glucose concentrations depend on oxidative phosphorylation rather than solely glycolysis. Importantly, continuous exposure to the compounds was required to achieve effective treatment. Nitazoxanide, an FDA-approved antiprotozoal drug with excellent pharmacokinetic and safety profile, is the only molecule among the screening hits that reaches high plasma concentrations persisting for up to a few hours after single oral dose. Nitazoxanide activated the AMPK pathway and downregulated c-Myc, mTOR, and Wnt signaling at clinically achievable concentrations. Nitazoxanide combined with the cytotoxic drug irinotecan showed anticancer activity in vivo. We here report that the FDA-approved anthelmintic drug nitazoxanide could be a potential candidate for advancement into cancer clinical trials.

Stored energies in electric and magnetic current densities for small antennas

Electric and magnetic currents are essential to describe electromagnetic-stored energy, and the associated antenna Q and the partial directivity to antenna Q-ratio, D / Q , for arbitrarily shaped structures. The upper bound of previous D / Q results for antennas modelled by electric currents is accurate enough to be predictive. This motivates us to develop the analysis required to determine upper and/or lower bounds for electromagnetic problems that include magnetic model currents. Here we derive new expressions for the stored energies, which are used to determine antenna Q bounds and D / Q bounds for the combination of electric and magnetic currents, in the limit of electrically small antennas. In this investigation, we show both new analytical results and we illustrate numerical realizations of them. We show that the lower bound of antenna Q is inversely proportional to the largest eigenvalue of certain combinations of the electric and magnetic polarizability tensors. These results are an extension of the electric only currents, which come as a special case. The proposed method to determine the minimum Q -value which is based on the new expressions for the stored energies, also yields a family of current-density minimizers for optimal electric and magnetic currents that can lend insight into antenna designs.

A microwave imaging-based technique to localize an in-body RF source for biomedical applications

In some biomedical applications such as wireless capsule endoscopy, the localization of an in-body radio-frequency (RF) source is important for the positioning of any abnormality inside the gastrointestinal tract. With knowledge of the location, therapeutic operations can be performed precisely at the position of the abnormality. Electrical properties (relative permittivity and conductivity) of the tissues and their distribution are utilized to estimate the position. This paper presents a method for the localization of an in-body RF source based on microwave imaging. The electrical properties of the tissues and their distribution at 403.5 MHz are found from microwave imaging and the position of an RF source is then estimated based on the image. The method is applied on synthetic noisy data, obtained after the addition of white Gaussian noise to simulated data of a simple circular phantom, and a realistic phantom in a 2-D case. The root-mean-square of the error distance between the actual and the estimated position is found to be within 10 and 4 mm for the circular and the realistic phantom, respectively, showing the capability of the proposed algorithm to work with a good accuracy even in the presence of noise for the localization of the in-body RF source.

Sublingual immunotherapy alters expression of IL-4 and its soluble and membrane-bound receptors

Seasonal allergic rhinitis (SAR) is a disease of increasing prevalence, which results from an inappropriate T helper cell, type 2 (Th2) response to pollen. Specific immunotherapy (SIT) involves repeated treatment with small doses of pollen and can result in complete and lasting reversal of SAR. Here, we assayed the key Th2 cytokine, IL-4, and its soluble and membrane-bound receptor in patients with SAR before and after SIT. Using allergen-challenge assays, we found that SIT treatment decreased IL-4 cytokine levels, as previously reported. We also observed a significant decrease in the IL-4 membrane-bound receptor (mIL4R) at the level of both mRNA and protein. SIT treatment resulted in a significant increase in the inhibitory soluble IL-4 receptor (sIL4R). Reciprocal changes in mIL4R and sIL4R were also observed in patient serum. Altered mIL4R and sIL4R is a novel explanation for the positive effects of immunotherapy with potential basic and clinical research implications.

The Allergic Airway Inflammation Repository--a user-friendly, curated resource of mRNA expression levels in studies of allergic airways

Public microarray databases allow analysis of expression levels of candidate genes in different contexts. However, finding relevant microarray data is complicated by the large number of available studies. We have compiled a user-friendly, open-access database of mRNA microarray experiments relevant to allergic airway inflammation, the Allergic Airway Inflammation Repository (AAIR, http://aair.cimed.ike.liu.se/). The aim is to allow allergy researchers to determine the expression profile of their genes of interest in multiple clinical data sets and several experimental systems quickly and intuitively. AAIR also provides quick links to other relevant information such as experimental protocols, related literature and raw data files.

Urban air quality: the challenge of traffic non-exhaust emissions

About 400,000 premature adult deaths attributable to air pollution occur each year in the European Region. Road transport emissions account for a significant share of this burden. While important technological improvements have been made for reducing particulate matter (PM) emissions from motor exhausts, no actions are currently in place to reduce the non-exhaust part of emissions such as those from brake wear, road wear, tyre wear and road dust resuspension. These "non-exhaust" sources contribute easily as much and often more than the tailpipe exhaust to the ambient air PM concentrations in cities, and their relative contribution to ambient PM is destined to increase in the future, posing obvious research and policy challenges. This review highlights the major and more recent research findings in four complementary fields of research and seeks to identify the current gaps in research and policy with regard to non-exhaust emissions. The objective of this article is to encourage and direct future research towards an improved understanding on the relationship between emissions, concentrations, exposure and health impact and on the effectiveness of potential remediation measures in the urban environment.

Inferred cosmic-ray spectrum from Fermi large area telescope γ-ray observations of Earth's limb

Recent accurate measurements of cosmic-ray (CR) species by ATIC-2, CREAM, and PAMELA reveal an unexpected hardening in the proton and He spectra above a few hundred GeV, a gradual softening of the spectra just below a few hundred GeV, and a harder spectrum of He compared to that of protons. These newly discovered features may offer a clue to the origin of high-energy CRs. We use the Fermi Large Area Telescope observations of the γ-ray emission from Earth's limb for an indirect measurement of the local spectrum of CR protons in the energy range ∼90  GeV-6  TeV (derived from a photon energy range 15 GeV-1 TeV). Our analysis shows that single power law and broken power law spectra fit the data equally well and yield a proton spectrum with index 2.68±0.04 and 2.61±0.08 above ∼200  GeV, respectively.

Challenges of conducting experimental studies within a clinical nursing context

In recent years, several distinguished scholars have advocated for nursing research that may carry strong evidence for practice. Their advocacy have highlighted that nursing science has reached a point where as nurse researchers we need to develop the questions we ask and design studies that have the power to produce solid, translational, evidence-based knowledge. To do so, we need to carry out experimental tests on complex, everyday nursing interventions and activities. We also need to create public space to present accounts of our endeavours pursuing this type of design in clinical practice. This paper will discuss some of the most important insights gained from conducting a quasi-experimental study in which the aim was to investigate the effect of a theory-based intervention, targeting knowledge and attitudes among registered nurses regarding cancer pain management. The importance of careful practical and methodological planning is emphasised, and the need for participation-friendly interventions is discussed.

Screening for phenotype selective activity in multidrug resistant cells identifies a novel tubulin active agent insensitive to common forms of cancer drug resistance

BACKGROUND

Drug resistance is a common cause of treatment failure in cancer patients and encompasses a multitude of different mechanisms. The aim of the present study was to identify drugs effective on multidrug resistant cells.

METHODS

The RPMI 8226 myeloma cell line and its multidrug resistant subline 8226/Dox40 was screened for cytotoxicity in response to 3,000 chemically diverse compounds using a fluorometric cytotoxicity assay (FMCA). Follow-up profiling was subsequently performed using various cellular and biochemical assays.

RESULTS

One compound, designated VLX40, demonstrated a higher activity against 8226/Dox40 cells compared to its parental counterpart. VLX40 induced delayed cell death with apoptotic features. Mechanistic exploration was performed using gene expression analysis of drug exposed tumor cells to generate a drug-specific signature. Strong connections to tubulin inhibitors and microtubule cytoskeleton were retrieved. The mechanistic hypothesis of VLX40 acting as a tubulin inhibitor was confirmed by direct measurements of interaction with tubulin polymerization using a biochemical assay and supported by demonstration of G2/M cell cycle arrest. When tested against a broad panel of primary cultures of patient tumor cells (PCPTC) representing different forms of leukemia and solid tumors, VLX40 displayed high activity against both myeloid and lymphoid leukemias in contrast to the reference compound vincristine to which myeloid blast cells are often insensitive. Significant in vivo activity was confirmed in myeloid U-937 cells implanted subcutaneously in mice using the hollow fiber model.

CONCLUSIONS

The results indicate that VLX40 may be a useful prototype for development of novel tubulin active agents that are insensitive to common mechanisms of cancer drug resistance.

The policy relevance of wear emissions from road transport, now and in the future--an international workshop report and consensus statement

Road transport emissions are a major contributor to ambient particulate matter concentrations and have been associated with adverse health effects. Therefore, these emissions are targeted through increasingly stringent European emission standards. These policies succeed in reducing exhaust emissions, but do not address "nonexhaust" emissions from brake wear, tire wear, road wear and suspension in air of road dust. Is this a problem? To what extent do nonexhaust emissions contribute to ambient concentrations of PM10 or PM2.5? In the near future, wear emissions may dominate the remaining traffic-related PM10 emissions in Europe, mostly due to the steep decrease in PM exhaust emissions. This underlines the need to determine the relevance of the wear emissions as a contribution to the existing ambient PM concentrations, and the need to assess the health risks related to wear particles, which has not yet received much attention. During a workshop in 2011, available knowledge was reported and evaluated so as to draw conclusions on the relevance of traffic-related wear emissions for air quality policy development. On the basis of available evidence, which is briefly presented in this paper it was concluded that nonexhaust emissions and in particular suspension in air of road dust are major contributors to exceedances at street locations of the PM10 air quality standards in various European cities. Furthermore, wear-related PM emissions that contain high concentrations of metals may (despite their limited contribution to the mass of nonexhaust emissions) cause significant health risks for the population, especially those living near intensely trafficked locations. To quantify the existing health risks, targeted research is required on wear emissions, their dispersion in urban areas, population exposure, and its effects on health. Such information will be crucial for environmental policymakers as an input for discussions on the need to develop control strategies.

IMPLICATIONS

Road transport particulate matter (PM) emissions are associated with adverse health effects. Stringent policies succeed in reducing the exhaust PM emissions, but do not address "nonexhaust" emissions from brake wear, tire wear, road wear, and suspension in air of road dust. In the near future the nonexhaust emissions will dominate the road transport PM emissions. Based on the limited available evidence, it is argued that dedicated research is required on nonexhaust emissions and dispersion to urban areas from both an air quality and a public health perspective. The implicated message to regulators and policy makers is that road transport emissions continue to be an issue for health and air quality, despite the encouraging rapid decrease of tailpipe exhaust emissions.

Monozygotic twins discordant for intermittent allergic rhinitis differ in mRNA and protein levels

Monozygotic (MZ) twins discordant for complex diseases may help to find disease mechanisms that are not due to genetic variants. Intermittent allergic rhinitis (IAR) is an optimal disease model because it occurs at defined time points each year, owing to known external antigens. We hypothesized that MZ twins discordant for IAR could help to find gene expression differences that are not dependent on genetic variants. We collected blood outside of the season from MZ twins discordant for IAR, challenged their peripheral blood mononuclear cells (PBMC) with pollen allergen in vitro, collected supernatants and isolated CD4+ T cells. We identified disease-relevant mRNAs and proteins that differed between the discordant MZ twins. By contrast, no differences in microRNA expression were found. Our results indicate that MZ twins discordant for IAR is an optimal model to identify disease mechanisms that are not due to genetic variants.

Early detection of colorectal cancer: A proteomic screening study for plasma biomarkers

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Background: Colorectal cancer (CRC) is the third most frequent cancer disease in the US. As the 5 year survival is closely associated to stage of disease at the time of diagnosis, patients with localized tumor limited to the colon or rectum have more than 90% chance of 5 year survival, while tumors spreading to regional lymph nodes or to distant organs, have a 5 year survival rate of 69% and 12%, respectively. Since late diagnosis is equal to a poor prognosis for the patients, biomarker guided early detection could make a difference for these patients. One strategy is blood based assays, where we hypothesis that a tumor and its microenvironment will lead to a deposition of specific proteins in the blood. However, due to the complexity of plasma, it is not only a biological but also a technical challenge to detect the proteins specific for CRC. Consequently, we combined the technical evaluation of multiplex proximity probing assays (PPA) with the search for relevant biomarkers for CRC. Each of the protein assays were based on thorough literature studies on the biology of CRC.

Methods: Proteins were measured using multiplex PPA. Each assay was constructed from commercially available antibodies conjugated to two DNA oligonucleotides. When the antibodies from one assay bind the target protein simultaneously, it enables the DNA oligonucleotides to be either enzymatic ligated or extended to a PCR amplicon. This PCR amplicon reflects the identity of the proteins and can be quantified by real-time PCR. We evaluated the assays and searched for potential early markers using a collection of case-control plasma samples from a larger endoscopy study. In total we measure the levels of 150 different proteins in 296 human plasma samples from 74 CRC patients, 74 healthy individuals, 74 adenoma patients, and 74 patients with non-cancer diseases.

Results: We have a successrate of 80%, the sensitivity is for most assays below 5 pM, and we find no cross-reactivity in chicken plasma for any of the assays. We previous reported that CEA, TIMP-1, CA242, and IL8 were upregulated in CRC plasma. These proteins were also identified in our extended study and the data will be presented.

Conclusions: We find potential early markers, which we will validate in new sample material.

Measurement of separate cosmic-ray electron and positron spectra with the fermi large area telescope

We measured separate cosmic-ray electron and positron spectra with the Fermi Large Area Telescope. Because the instrument does not have an onboard magnet, we distinguish the two species by exploiting Earth's shadow, which is offset in opposite directions for opposite charges due to Earth's magnetic field. We estimate and subtract the cosmic-ray proton background using two different methods that produce consistent results. We report the electron-only spectrum, the positron-only spectrum, and the positron fraction between 20 and 200 GeV. We confirm that the fraction rises with energy in the 20-100 GeV range. The three new spectral points between 100 and 200 GeV are consistent with a fraction that is continuing to rise with energy.

Effects of prismatic glasses including optometric correction on head and neck kinematics, perceived exertion and comfort during dental work in the oral cavity--a randomised controlled intervention

AIM

To quantify the effects of using prismatic glasses including optometric correction, on head and neck kinematics, perceived exertion and comfort, during work in the oral cavity.

METHODS

The study population consisted of forty-five participants. After a basic ergonomic education, baseline measurements of head and neck kinematics were made using inclinometers. Perceived exertion and comfort were rated by the participants. An intervention group (n = 25), selected at random from the participants, received prismatic glasses and optometric correction when needed and were compared with a control group (n = 20). Follow up assessments were made after the intervention.

RESULTS

At follow up there was a reduction in both the intervention group (8.7°) and in the control group (3.6°) regarding head flexion. Neck flexion was reduced by 8.2° in the intervention group and 3.3° in the control group. The difference between the intervention and the control groups, i.e. the effect of the intervention, was statistically significant for both head (5.1°; p = 0.009) and neck (4.9°; p = 0.045) flexion. No effect of the intervention was seen regarding perceived exertion and comfort.

CONCLUSION

The reduction in head and neck flexion achieved by the prismatic glasses is likely to reduce the risk of neck pain during dental work. The effect of the prismatic lenses could not be separated from the effect of the optometric correction. The possible effect of the ergonomic education was not evaluated.

P3-13-03: Long-Term Symptoms after Radiotherapy of Supraclavicular Lymph Nodes in Breast Cancer Patients

Background and Purpose: Irradiation of the supraclavicular lymph nodes has historically been shown to increase the risk of brachial plexopathy with neurological problems in the upper limb. The purpose of this study was to compare long-term symptoms after modern radiotherapy (based on 3D dose planning) in breast cancer patients with or without irradiation of the supraclavicular lymph nodes.

Material and Methods: We collected information from 814 recurrence free women consecutively treated with adjuvant radiotherapy for breast cancer at the Sahlgrenska University Hospital in Gothenburg, Sweden, 1999 to 2004. The women had breast conserving surgery or mastectomy with axillary dissection or sentinel node biopsy. The breast area was irradiated to 50 Gy in 2.0 Gy fractions. Women with more than three lymph node metastases had regional radiotherapy to the supraclavicular lymph nodes delivered in 2.0 Gy fractions up to 50 Gy. Systemic treatments were given according to regional guidelines. In this study the women were classified into three groups depending on if they had axillary dissection and regional radiotherapy. The first group had both axillary dissection and regional radiotherapy, the second group had axillary dissection without regional radiotherapy, and the third group had sentinel node biopsy (i.e. no axillary dissection) without regional radiotherapy. Three to eight years after radiotherapy, the women received a questionnaire asking about paresthesia, pain and strength in the upper limb.

Results: Among women with axillary dissection and regional radiotherapy 38/192 (19.8%) reported paresthesia in the hand compared to 68/505 (13.5%) among women with axillary dissection without regional radiotherapy; relative risk (RR) 1.47; 95% confidence interval (95% CI) 1.02 - 2.11, and compared to 9/112 (8.0%) among women with sentinel node biopsy without regional radiotherapy; RR 2.46 (95% CI 1.24−4.90). Type of breast surgery, number of examined axillary lymph nodes, and chemotherapy had no impact on the occurrence of paresthesia. Age was an effect modifier among the women with axillary dissection and regional radiotherapy; up to 49 years of age 26.8% reported paresthesia (RR 2.45; 95% CI 1.05−5.73), between 50 and 59 years of age 19.7% reported paresthesia (RR 1.81; 95% CI 0.73−4.44), and above 59 years of age 10.9% reported paresthesia (RR 1.00 Reference). We found no statistically significant differences between the groups regarding pain or decreased strength.

Conclusions: Radiotherapy to the supraclavicular lymph nodes increases the occurrence of paresthesia in the hand. The effect was mainly seen among younger women. Dose/volume-response analysis regarding paresthesia will be presented at the meeting.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-13-03.

Constraining dark matter models from a combined analysis of Milky Way satellites with the Fermi Large Area Telescope

Satellite galaxies of the Milky Way are among the most promising targets for dark matter searches in gamma rays. We present a search for dark matter consisting of weakly interacting massive particles, applying a joint likelihood analysis to 10 satellite galaxies with 24 months of data of the Fermi Large Area Telescope. No dark matter signal is detected. Including the uncertainty in the dark matter distribution, robust upper limits are placed on dark matter annihilation cross sections. The 95% confidence level upper limits range from about 10(-26)  cm3  s(-1) at 5 GeV to about 5×10(-23)   cm3  s(-1) at 1 TeV, depending on the dark matter annihilation final state. For the first time, using gamma rays, we are able to rule out models with the most generic cross section (∼3×10(-26)  cm3  s(-1) for a purely s-wave cross section), without assuming additional boost factors.

Cytokine mapping in cerebrospinal fluid and blood in multiple sclerosis patients without oligoclonal bands

Objective: Since there are clinical and genetic differences between MS patients with intrathecal oligoclonal bands (OCB+) in the cerebrospinal fluid (CSF) compared with those without (OCB−), the aim was to find out if OCB− patients showed a different pattern of cytokine immune activation compared with OCB+ patients.

Methods: The study included 25 MS patients (10 OCB− and 15 OCB+) and 13 controls. A panel of cytokines was measured; IL-1β, IL-6, IL-8/CXCL8, IL-10, TNF and GM-CSF in serum, CSF and in supernatants from polyclonally stimulated blood mononuclear cells, where also levels of IL-12p40, IL-13, IL-15, IL-17 and IFN-γ were measured. The concentrations of soluble (s) VCAM-1 and sCD14 were measured in serum and CSF.

Results: In general, there were no extensive differences in cytokine concentrations between the OCB− and OCB+ groups.

Conclusion: OCB− MS patients do not seem to constitute a separate entity concerning inflammatory parameters measured as cytokine concentrations in CSF and blood.

Image reconstruction in microwave tomography using a dielectric Debye model

In this paper, quantitative dielectric image reconstruction based on broadband microwave measurements is investigated. A time-domain-based algorithm is derived where Debye model parameters are reconstructed in order to take into account the strong dispersive behavior found in biological tissue. The algorithm is tested with experimental and numerical data in order to verify the algorithm and to investigate improvements in the reconstructed image resulting from the improved description of the dielectric properties of the tissue when using broadband data. The comparison is made in relation to the more commonly used conductivity model. For the evaluation, two examples were considered, the first was a lossy saline solution and the second was less lossy tap water. Both liquids are strongly dispersive and used as a background medium in the imaging examples. The results show that the Debye model algorithm is of most importance in the tap water for a bandwidth of more than 1.5 GHz. Also the saline solution exhibits a dispersive behavior but since the losses restrict the useful bandwidth, the Debye model is of less significance even if somewhat larger and stronger artifacts can be seen in the conductivity model reconstructions.