bluuebunny/crossref_metadata_2025 huggingface dataset:
Sensation‐Seeking Attributes Associated with Storm‐Chasing Tourists: Implications for Future Engagement
Authors: Xu Shuangyu , Barbieri Carla , Stanis Sonja Wilhelm , Market Patrick S.
Published: June 2011

This study explores recreational storm chasing, a new form of niche tourism. In particular, this study examines sensation‐seeking traits associated with participants' socio‐demographics, storm‐chasing involvement and tour satisfaction levels. Results show that recreational storm chasers scored highest on Experience Seeking and lowest on Boredom Susceptibility sensation‐seeking dimensions. Correlation tests showed that several socio‐demographic, storm‐chasing involvement and tour satisfaction indicators are associated with Thrill and Adventure Seeking, Boredom Susceptibility, and Experience Seeking dimensions. Marketing and management implications of study results also are discussed. Copyright © 2011 John Wiley & Sons, Ltd.
SEVERITY OF SALINITY ACCURATELY DETECTED AND CLASSIFIED ON A PADDOCK SCALE WITH HIGH RESOLUTION MULTISPECTRAL SATELLITE IMAGERY
Authors: Setia R. , Lewis M. , Marschner P. , Raja Segaran R. , Summers D. , Chittleborough D.
Published: June 2011

We hypothesised that digital mapping of various forms of salt‐affected soils using high resolution satellite imagery, supported by field studies, would be an efficient method to classify and map salinity, sodicity or both at paddock level, particularly in areas where salt‐affected patches are small and the effort to map these by field‐based soil survey methods alone would be inordinately time consuming. To test this hypothesis, QuickBird satellite data (pan‐sharpened four band multispectral imagery) was used to map various forms of surface‐expressed salinity in an agricultural area of South Australia. Ground‐truthing was performed by collecting 160 soil samples over the study area of 159 km2. Unsupervised classification of the imagery covering the study area allowed differentiation of severity levels of salt‐affected soils, but these levels did not match those based on measured electrical conductivity (EC) and sodium adsorption ratio (SAR) of the soil samples, primarily because the expression of salinity was strongly influenced by paddock‐level variations in crop type, growth and prior land management. Segmentation of the whole image into 450 paddocks and unsupervised classification using a paddock‐by‐paddock approach resulted in a more accurate discrimination of salinity and sodicity levels that was correlated with EC and SAR. Image‐based classes discriminating severity levels of salt‐affected soils were significantly related with EC but not with SAR. Of the spectral bands, bands 2 (green, 520–600 nm) and 4 (near‐infrared, 760–900 nm) explained the majority of the variation (99 per cent) in the spectral values. Thus, paddock‐by‐paddock classification of QuickBird imagery has the potential to accurately delineate salinity at farm level, which will allow more informed decisions about sustainable agricultural management of soils. Copyright © 2011 John Wiley & Sons, Ltd.
Development of Disulfide Core‐Crosslinked Pluronic Nanoparticles as an Effective Anticancer‐Drug‐Delivery System
Authors: Abdullah‐Al‐Nahain  , Lee Haeshin , Lee Young Sun , Lee Kang Dae , Park Sung Young
Published: June 2011

Thiolated Pluronic (Plu‐SH) nanoparticles are developed as potential articulate, target‐specific anticancer‐drug carriers for intracellular drug release triggered by the difference in redox potential in tumor cells. The cores of the micelles are formed by the disulfide bonds of the functionalized Pluronic F127, when dissolved in an aqueous solution. The nanoparticles are 95.6 ± 18.6 nm in size, and 235.6 ± 63.7 nm after encapsulation of the hydrophobic drug molecules. The drug‐loaded micelles show effective stability in blood‐plasma conditions and the kinetics of micelle stability and drug release are shown. Paclitaxel‐loaded micelles display approximately 39% cell viability in A549 cells.

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Eco‐friendly Poly(butylene 1,4‐cyclohexanedicarboxylate): Relationships Between Stereochemistry and Crystallization Behavior
Authors: Celli Annamaria , Marchese Paola , Sullalti Simone , Berti Corrado , Barbiroli Giancarlo
Published: June 2011

Poly(butylene 1,4‐cyclohexanedicarboxylate) (PBCHD) is an environmentally friendly material, as it can be obtained from biomass (although nowadays it is prepared from petroleum resources) and is potentially biodegradable. Moreover, the aliphatic rings along the chains lend interesting characteristics, for example good mechanical properties and resistance to weather for outdoor applications. As many properties, such as biodegradability, strongly depend on crystallinity, a study of the crystallizability of PBCHDs is very meaningful. Equilibrium melting temperatures and crystallization rates are strongly affected by the cis/trans ratio of the 1,4‐cyclohexylene units. Indeed, only the trans isomer can form crystals, whereas the cis isomer is fully excluded from the crystalline phase. All thermal data can be well understood by considering PBCHD as a random copolymer with crystallizable (trans isomer) and noncrystallizable (cis isomer) components, which only differ for the stereochemistry of the aliphatic rings.

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Atom Transfer Radical Dispersion Polymerization of Styrene in the Presence of PEO‐based Macromonomer
Authors: Li Wenwen , Matyjaszewski Krzysztof
Published: June 2011

Commercially available poly(ethylene oxide) macromonomers are successfully used as reactive stabilizers for atom transfer radical dispersion/precipitation polymerization of styrene. Polystyrene particles with PEO chains covalently anchored on the surfaces are obtained. Control over both the particle size and polymer chain growth is achieved using a two‐stage technique consisting of an initial free radical polymerization (FRP) for the nucleation followed by a reverse atom transfer radical polymerization (ATRP) for the controlled polymerization process. The limited monomer conversion at the FRP step ensures that the overall polymerization process is mainly controlled by the reverse ATRP step, resulting in the formation of particles containing well‐defined polymer chains.

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Poly(cyclic imino ether)s Beyond 2‐Substituted‐2‐oxazolines
Authors: Bloksma Meta M. , Schubert Ulrich S. , Hoogenboom Richard
Published: June 2011

2‐Oxazolines (2‐OZO) are 5‐membered cyclic imino ethers whose cationic ring‐opening polymerization (CROP) mechanism and resulting polymer properties are extensively studied. However, also 6‐ and 7‐membered cyclic imino ethers can be polymerized via CROP. Together with the much less studied 4‐ and 5‐substituted main‐chain chiral poly(2‐oxazoline)s (P‐2‐OZO), these compounds are interesting monomers to enhance the versatility of (co)poly(cyclic imino ether)s. To emphasize the potential of such alternative cyclic imino ether monomers, we provide an overview on the polymerizations of 2‐oxazine (2‐OZI) and chiral 4‐ and 5‐substituted 2‐OZO as well as of selected properties of the resulting polymers. In addition, the hydrolysis of these polymers into the corresponding poly(alkylene imine)s will be addressed.

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Photocatalytically Active Polyelectrolyte/Nanoparticle Films for the Elimination of a Model Odorous Gas
Authors: Dontsova Dariya , Keller Valérie , Keller Nicolas , Steffanut Pascal , Félix Olivier , Decher Gero
Published: June 2011

Virtually transparent films of Aeroxide TiO2 P25 were fabricated via layer‐by‐layer assembly with sodium poly(styrene sulfonate). Nanoscale films are formed on model surfaces for characterization or inside of cylindrical reactors for investigating the catalytic properties. Films are fairly homogeneous and smooth over large areas and show different optical interference colors depending on film thickness. The application‐relevant photocatalytic performance of such films toward on‐flow degradation of hydrogen sulfide under UV‐A irradiation was investigated. Scanning electron microscopy reveals a nanoporous structure allowing for the permeation of gas. Consequently, the catalytic efficiency of the films increases with increasing film thickness retaining a considerable activity of the corresponding nanoparticle powder. Scheme 1 depicts in a general way the functionalized reactor and the principle of the measurement.
Application of Poly(3‐hexylthiophene) Functionalized with an Anchoring Group in Dye‐sensitized Solar Cells
Authors: Warnan Julien , Pellegrin Yann , Blart Errol , Odobel Fabrice , Zhang Wei , Liu Bin , Babu Veluru Jagadeesh , Ramakrishna Seeram
Published: June 2011

A series of three poly(3‐hexylthiophene) functionalized either with a cyanoacetic acid (CA) or a rhodanine‐3‐acetic acid anchoring groups were synthesized and characterized. The TiO2 based dye‐sensitized solar cells have been fabricated and performances were tested. We show that shorter chain length (15 thiophene units) linked to CA binding group gives good performances as Jsc, Voc, FF and η(%) were 6.93(mA · cm−2), 0.65(V), 0.67 and 3.02%, respectively. A maximum IPCE of ≈50% at 500 nm was recorded with a liquid electrolyte, under AM 1.5 simulated solar irradiance.

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Model Discrimination of Radical Desorption Kinetics in Emulsion Polymerisation
Authors: Fellows Christopher M. , Murison Robert D. , Russell Gregory T.
Published: June 2011

Analysis of published experimental data on monomeric radical diffusion in the emulsion polymerisation of styrene shows that it can be quantitatively described equally well by non‐equilibrium diffusion from particles, where all parameters are derived from properties of the discrete phase, or by steady‐state diffusion where all parameters are derived from properties of the continuous phase. The non‐equilibrium model better describes an observed experimental trend to a reduced desorption rate coefficient at higher weight fraction of polymer in the particles. The theoretical upper bound of the non‐equilibrium model is also higher than the theoretical upper bound of the steady‐state model allowing fits to experimental data which must be discarded as anomalous in the continuous phase model.

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Cortical gray matter changes in primary blepharospasm: A voxel‐based morphometry study
Authors: Martino Davide , Di Giorgio Annabella , D'Ambrosio Enrico , Popolizio Teresa , Macerollo Antonella , Livrea Paolo , Bertolino Alessandro , Defazio Giovanni
Published: June 2011

Previous voxel‐based morphometry studies of patients with primary blepharospasm documented gray matter volumetric differences of the striatum, cerebellum, thalamus, and parietal lobe areas. However, these results were inconsistent across studies, which recruited relatively small samples and did not always provide detailed clinical information on patients with blepharospasm. The objective of this study was to analyze whole‐brain gray matter volume in a larger sample of patients with blepharospasm and to expand on previous works by evaluating whether clinical features of blepharospasm correlate to whole‐brain gray matter changes. Voxel‐based morphometry was performed on 25 patients with primary adult‐onset blepharospasm and 24 healthy subjects (controls) matched for age, sex, and handedness. Clinical data were collected through a standardized interview. Severity of blepharospasm was measured using the Jankovic Rating Scale. Patients with blepharospasm had greater gray matter volume than controls in the right middle frontal gyrus, whereas patients with blepharospasm had smaller gray matter volume than controls in the left postcentral gyrus and left superior temporal gyrus. Spearman correlation analysis with Bonferroni correction failed to show significant correlations between gray matter volume and the explored clinical variables, comprising age at onset, disease duration, blepharospasm severity, presence of an effective geste antagoniste, and dose and duration of botulinum toxin treatment. Patients with blepharospasm exhibited gray matter volume differences exclusively in cortical regions highly relevant to sensory processing and cognitive modulation of motor behavior. Gray matter changes in the primary sensory cortex may represent a common trait of primary dystonias, including blepharospasm. © 2011 Movement Disorder Society
Functional magnetic resonance imaging exploration of combined hand and speech movements in Parkinson's disease
Authors: Pinto Serge , Mancini Laura , Jahanshahi Marjan , Thornton John S. , Tripoliti Elina , Yousry Tarek A. , Limousin Patricia
Published: June 2011

Among the repertoire of motor functions, although hand movement and speech production tasks have been investigated widely by functional neuroimaging, paradigms combining both movements have been studied less so. Such paradigms are of particular interest in Parkinson's disease, in which patients have specific difficulties performing two movements simultaneously. In 9 unmedicated patients with Parkinson's disease and 15 healthy control subjects, externally cued tasks (i.e., hand movement, speech production, and combined hand movement and speech production) were performed twice in a random order and functional magnetic resonance imaging detected cerebral activations, compared to the rest. F‐statistics tested within‐group (significant activations at P values < 0.05, familywise error corrected), between‐group, and between‐task comparisons (regional activations significant at P values < 0.001, uncorrected, with cluster size > 10 voxels). For control subjects, the combined task activations comprised the sum of those obtained during hand movement and speech production performed separately, reflecting the neural correlates of performing movements sharing similar programming modalities. In patients with Parkinson's disease, only activations underlying hand movement were observed during the combined task. We interpreted this phenomenon as patients' potential inability to recruit facilitatory activations while performing two movements simultaneously. This lost capacity could be related to a functional prioritization of one movement (i.e., hand movement), in comparison with the other (i.e., speech production). Our observation could also reflect the inability of patients with Parkinson's disease to intrinsically engage the motor coordination necessary to perform a combined task. © 2011 Movement Disorder Society
Disease‐related and genetic correlates of psychotic symptoms in Parkinson's disease
Authors: Factor Stewart A. , Steenland N. Kyle , Higgins Donald S. , Molho Eric S. , Kay Denise M. , Montimurro Jennifer , Rosen Ami R. , Zabetian Cyrus P. , Payami Haydeh
Published: June 2011

Our aim was to examine disease‐related and genetic correlates of the development of psychotic symptoms in a large population of patients with Parkinson's disease. We studied 500 patients with Parkinson's disease from the NeuroGenetics Research Consortium using logistic regression models. Predictors were demographic, clinical (motor/nonmotor features), and genetic, measured as continuous or dichotomous variables. Continuous measures were divided into population‐based tertiles. Results are given as odds ratios (95% confidence intervals) for dichotomous variables and by ascending tertile for continuous variables. Psychotic symptoms were associated with increasing age: 4.86 (1.62–14.30) and 6.25 (2.09–18.74) (test for trend: P = 0.01); and duration of disease: 3.81 (1.23–11.76) and 5.33 (1.68–16.89) (test for trend: P = 0.03). For nonmotor features, we demonstrated positive trends with depression: 1.31 (0.47–3.61) and 5.01 (2.04–12.33) (test for trend: P < 0.0001); cognitive dysfunction: 0.69 (0.26–1.84) and 2.51 (1.00–6.29) (test for trend: P = 0.03); and an excess for those with sleep disorders: 2.00 (1.03–3.89) (P = 0.04). Psychotic symptoms were not associated with tremor or postural instability scores, but there was an association with freezing of gait: 3.83 (1.67–8.75) (P < 0.002). Psychotic symptoms were not associated with the presence of any examined polymorphisms in the apolipoprotein, alpha‐synuclein, or microtubule associated protein tau genes. This is the largest study to examine correlates of psychotic symptoms in Parkinson's disease. We discovered a novel association with freezing of gait. We demonstrated an association with depression and duration of disease, both of which were inconsistently related in previous studies, and confirmed the association with age, cognitive dysfunction, and sleep disorders. © 2011 Movement Disorder Society
Extreme task specificity in writer's cramp
Authors: Shamim Ejaz A. , Chu Jason , Scheider Linda H. , Savitt Joseph , Jinnah H.A. , Hallett Mark
Published: June 2011

Background:

Focal hand dystonia may be task specific, as is the case with writer's cramp. In early stages, task specificity can be so specific that it may be mistaken for a psychogenic movement disorder.

Methods:

We describe 4 patients who showed extreme task specificity in writer's cramp. They initially only had problems writing either a single letter or number. Although they were largely thought to be psychogenic, they progressed to typical writer's cramp.

Conclusions:

Early recognition of this condition may provide an opportunity for early initiation of treatment. © 2011 Movement Disorder Society
Increased muscle belly and tendon stiffness in patients with Parkinson's disease, as measured by myotonometry
Authors: Marusiak Jarosław , Jaskólska Anna , Budrewicz Sławomir , Koszewicz Magdalena , Jaskólski Artur
Published: June 2011

Background:

Based on Davis's law, greater tonus of the muscle belly in individuals with Parkinson's disease can create greater tension in the tendon, leading to structural adjustment and an increase in tendon stiffness. Our study aimed to separately assess passive stiffness in the muscle belly and tendon in medicated patients with Parkinson's disease, using myotonometry.

Methods:

We tested 12 patients with Parkinson's disease and 12 healthy matched controls. Passive stiffness of muscle belly and tendon was estimated by myotonometry, electromyography, and mechanomyography in relaxed biceps and triceps brachii muscles.

Results:

Compared with controls, patients with Parkinson's disease had higher stiffness in the muscle belly and tendon of the biceps brachii and in the tendon of the triceps brachii. In patients with Parkinson's disease, there was a positive correlation between muscle belly stiffness and parkinsonian rigidity in the biceps brachii.

Conclusion:

Patients with Parkinson's disease have higher passive stiffness of the muscle belly and tendon than healthy matched controls. © 2011 Movement Disorder Society
Feeding dystonia in McLeod Syndrome
Authors: Gantenbein Andreas R. , Damon‐Perrière Nathalie , Bohlender Jörg E. , Chauveau Marie , Latxague Chrystelle , Miranda Marcelo , Jung Hans H. , Tison François
Published: June 2011

Background:

The X‐linked McLeod syndrome belongs to the group of neuroacanthocytosis syndromes and has a Huntington‐disease–like phenotype with a choreatic movement disorder, cognitive alterations, and psychiatric symptoms. Another neuroacanthocytosis syndrome, the autosomal recessive chorea‐acanthocytosis, has a similar presentation, but distinct clinical features, believed to be characteristic, such as tongue protrusion dystonia, feeding dystonia, and rubber‐man–like appearance.

Methods:

This work comprised a case series of 3 patients with McLeod syndrome.

Results:

The 3 patients with McLeod syndrome developed severe feeding dystonia and tongue protrusion as well as rubber‐man–like appearance in 1 patient during the course of the disease.

Conclusion:

These observations indicate that there is an extended phenotypic overlap between McLeod syndrome and chorea‐acanthocytosis. © 2011 Movement Disorder Society
Analysis of temperature series: estimation of missing data and homogeneity test
Authors: Firat Mahmut , Dikbas Fatih , Koc A. Cem , Gungor Mahmud
Published: June 2011

In this study, missing value analysis and homogeneity tests were applied on the 267 meteorological stations having temperature records throughout Turkey. The monthly and annual mean temperature data of stations operated by the Turkish State Meteorological Service (DMI) for the period 1968–1998 were considered. For each station, each month was analysed separately and the stations with more than 5 years missing values were eliminated. The missing values of the stations were extrapolated by the Expectation Maximization (EM) method using the data of the nearest gauging station (reference station). In consequence of the analysis, annual mean temperature data are obtained by using the monthly values. These data have to be hydrologically/statistically reliable if they are to be used in later hydrological, meteorological, climate change and estimation studies. For this reason, the Standard Normal Homogeneity Test (SNHT), the (Swed‐Eisenhart) Runs Test and the Pettitt homogeneity test were applied to detect inhomogeneities in the annual mean temperature series. Each test was evaluated separately and inhomogeneous stations were determined. Copyright © 2011 Royal Meteorological Society
How can meteorological observations and microclimate simulations improve understanding of 1913–2010 climate change around Abisko, Swedish Lapland?
Authors: Yang Zhenlin , Hanna Edward , Callaghan Terry V. , Jonasson Christer
Published: June 2011

A detailed analysis of 2 years' hourly microclimatic (mainly surface air temperature) data recently acquired from locations widely dispersed over 700 km2 in the Abisko catchment encompassing Lake Torneträsk in Swedish Lapland is presented in this study. This project is designed to explore the effects of microclimatic variability, past and future climate change (1913–2100) on regional vegetation and land‐use changes, at an unique Arctic ecological and climate monitoring site, to aid adaptation of stakeholders to future climate change. Dominant altitudinal lapse rate and radiation effects during summer are revealed in detailed analysis of spatial variations in temperature between the different sites, which become largely negated during winter when cold‐air ponding is much more significant. Moreover, near‐shore temperatures are moderated significantly by Lake Torneträsk during the spring lake‐ice melt season. The extent to which synoptic meteorological conditions affect these factors is explored. Examples of gridded temperature maps for the Abisko region are also presented, produced using a downscaling model based on the temperature data, which have numerous ecological and other applications. The long‐term Abisko Scientific Research Station meteorological record, which spans almost a century from 1913 to present is also explored, for evidence of climate change, to set the temperature logger data in a long‐term climate context. Exploratory analysis of the possible influence of future regional climate change on ecological/vegetation zones is also briefly discussed. Copyright © 2011 Royal Meteorological Society
Oral tolerance induction does not resolve gastrointestinal inflammation in a mouse model offoodallergy
Authors: Burggraf Manja , Nakajima‐Adachi Haruyo , Hachimura Satoshi , Ilchmann Anne , Pemberton Alan D. , Kiyono Hiroshi , Vieths Stefan , Toda Masako
Published: June 2011

Scope: Oral immunotherapy (OIT) involving continuous oral administration of allergenic foods has gained attention as a therapy for food allergies. To study the influence of oral administration of allergenic foods on gastrointestinal symptoms including inflammation, we established a mouse model of food‐induced intestinal allergy.

Methods and results: BALB/c mice were fed an egg white (EW) diet containing ovalbumin (OVA, a major EW allergen) after intraperitoneal sensitisation with OVA and Alum. The mice on the EW diet for one wk presented gastrointestinal symptoms (i.e. weight loss and soft stools) and inflammation in the small intestines (i.e. duodenum, jejunum and ileum). Further continuous EW diet resolved the weight loss but not the soft stools. Splenic CD4+ T‐cells of EW diet‐fed mice on the continuous diet showed less proliferation and cytokine production compared with those of control mice, suggesting tolerance induction by the diet. The continuous EW diet reduced levels of OVA‐specific IgE antibodies, but significantly aggravated the inflammation in the jejunum.

Conclusion: Our mouse model would be useful to investigate inflammatory and regulatory mechanisms in food‐induced intestinal allergies. Our results suggest potential gastrointestinal inflammation in patients undergoing OIT as continuous administration of allergenic foods, even though the therapy may induce clinical tolerance.
Suppression subtractive hybridization identifies bacterial genomic regions that are possibly involved in hBD‐2 regulation by enterocytes
Authors: Ghadimi Darab , Hassan Mohamed , Njeru Patrisio Njiru , de Vrese Michael , Geis Arnold , Shalabi Samweul I. , Abdel‐Razek Sabah T. , Abdel‐Khair Abd El‐Al A. , Heller Knut J. , Schrezenmeir Jürgen
Published: June 2011

Scope: Human β‐defensin 2 (hBD‐2) is an inducible antimicrobial peptide synthesized by the epithelium to counteract bacterial adherence and invasion. It has been suggested that probiotic bacteria sustain gut barrier function via induction of defensins. The goals of this study were (i) to evaluate the potential immunomodulatory effects of 11 different Lactobacillus fermentum strains isolated from Kimere, an African fermented pearl millet (Pennisetum glaucum) dough, on the hBD‐2 secretion by human intestinal CaCo‐2 cell line and (ii) to examine genetic differences between two strains of L. fermentum (K2‐Lb4 and K11‐Lb3) which differed in their effect on the production of hBD‐2 in this study.

Methods and results: Totally, 46 strains of L. fermentum from Kimere were isolated and characterized using molecular biology methods including pulsed‐field gel electrophoresis patterns. After performing time‐ and dose‐experiments, CaCo‐2 cells were incubated with or without bacteria for 12 h. L. fermentum PZ1162 was included as the positive control. Cell‐free supernatants were analyzed for hBD‐2 protein by enzyme‐linked immunosorbent assay (ELISA). To identify potential bacterial genes associated with hBD‐2 regulation, suppression subtractive hybridization (SSH) was used. Among the 11 strains tested, only two strains of bacteria, K11‐Lb3 and K2‐Lb6, significantly induced the production of hBD‐2 by CaCo‐2 cells. This effect was strain‐specific, dose‐dependent and particularly seems to be bacterial genomic‐dependent as manifested by SSH. L. fermentum strains with and without hBD‐2 inducing effect differed in genes encoding proteins involved in glycosylation of cell‐wall proteins e.g. glycosyltransferase, UDP‐N‐acetylglucosamine 2‐epimerase, rod shape‐determining protein MreC, lipoprotein precursors, sugar ABC transporters, and glutamine ABC transporter ATP‐binding protein.

Conclusion: This study implies that certain strains of L. fermentum isolated from Kimere may stimulate the intestinal innate defense through the induction of hBD‐2. The molecular basis of hBD‐2 induction by L. fermentum strain K11‐Lb3 may be based on glycosylated cell‐surface structures synthesized with the aid of glycosyltransferase, UDP‐N‐acetylglucosamine 2‐epimerase, and rod shape‐determining protein MreC.
Resveratrol derivatives as promising chemopreventive agents with improved potency and selectivity
Authors: Kondratyuk Tamara P. , Park Eun‐Jung , Marler Laura E. , Ahn Soyoun , Yuan Yang , Choi Yongsoo , Yu Rui , van Breemen Richard B. , Sun Bin , Hoshino Juma , Cushman Mark , Jermihov Katherine C. , Mesecar Andrew D. , Grubbs Clinton J. , Pezzuto John M.
Published: June 2011

Scope: Despite scores of investigations, the actual impact of resveratrol (3,5,4′‐trihydroxy‐trans‐stilbene) on human health, as a dietary component or supplement, remains moot. This is due to many factors, such as relatively low potency, pleiotropic mechanisms, and rapid metabolism. Nonetheless, as a promiscuous molecule that interacts with numerous targets, resveratrol can be viewed as a scaffold for designing structural relatives potentially capable of mediating more intense responses with greater mechanistic stringency.

Methods and results: We currently report the synthesis and biological evaluation of 92 stilbene analogs. The compounds were tested with in vitro assays for activation of quinone reductase 1, inhibition of quinone reductase 2, nitric oxide production, aromatase, NFκB, 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA)‐induced ornithine decarboxylase, or cyclooxygenase‐1 and ‐2, quenching of 2,2‐diphenyl‐1‐picrylhydrazyl free radical, interaction with estrogen receptors, and as antiproliferative agents. Several compounds were found to mediate responses with much greater potency than resveratrol; some mediated pleiotropic responses, as is the case with the parent molecule, but others were highly specific or totally inactive. When administered to rats, higher serum concentrations and greater stability was demonstrated with prototype lead molecules.

Conclusion: Owing to structural simplicity, facile syntheses are available for large‐scale production. These data support the promise of more advanced development of novel resveratrol derivatives as drug entities.
Immunological evaluation of the alcohol‐soluble protein fraction from gluten‐free grains in relation to celiac disease
Authors: Bergamo Paolo , Maurano Francesco , Mazzarella Giuseppe , Iaquinto Gaetano , Vocca Immacolata , Rivelli Anna Rita , De Falco Enrica , Gianfrani Carmen , Rossi Mauro
Published: June 2011

Celiac disease (CD) is a gluten‐sensitive enteropathy with an immune basis. We established the immune reactivity of the alcohol‐soluble fraction from two minor cereals (tef and millet) and two pseudocereals (amaranth and quinoa) which are believed to be nontoxic based on taxonomy. Grains were examined in intestinal T‐cell lines (iTCLs), cultures of duodenal explants from HLA‐DQ2+ CD patients and HLA‐DQ8 transgenic mice for signs of activation. Our data indicated that tef, millet, amaranth, and quinoa did not show any immune cross‐reactivity toward wheat gliadin, and therefore confirming their safety in the diet of CD patients.
Metabolites and tissue distribution of resveratrol in the pig
Authors: Azorín‐Ortuño María , Yáñez‐Gascón María J. , Vallejo Fernando , Pallarés Francisco J. , Larrosa Mar , Lucas Ricardo , Morales Juan C. , Tomás‐Barberán Francisco A. , García‐Conesa María T. , Espín Juan C.
Published: June 2011

Scope: trans‐Resveratrol (RES) and/(or) its metabolites exert many effects in vivo. Our aim was to study the metabolism and tissue distribution of RES using the pig, a mammal physiologically close to humans.

Methods and results: Forty‐seven tissues, organs and fluids were analyzed 6 h after intragastric RES administration (5.9 mg/kg body weight) using HPLC‐MS/MS. Twelve RES and seven dihydroresveratrol (DH‐RES) metabolites were detected. DH‐RES was the main metabolite in cecum, colon and rectum, whereas RES‐3‐O‐glucuronide was the most abundant one in fluids and organs. Approximately 74.5% of the total RES administered was recovered in the form of RES, DH‐RES and derived metabolites (65.1% along the gastrointestinal tract, 7.7% in urine, 1.2% in bile and 0.5% in organs). We report here, for the first time, the occurrence of RES ribosyl‐sulfate derivative, DH‐RES diglucuronide, DH‐RES sulfoglucuronide and DH‐RES disulfate as well as the metabolic profile of RES and DH‐RES in the aorta, lymph, lymph node, ovaries, uterus, cerebellum, pancreas, urinary bladder tissue, fat and muscle.

Conclusion: This study contributes to the clarification of the metabolism and tissue distribution of RES and could help to further understand the mechanisms underlying its effects.
Resveratrol and prostate cancer: Promising role for microRNAs
Authors: Dhar Swati , Hicks Chindo , Levenson Anait S.
Published: June 2011

Scope:Resveratrol (Res) has anticancer activity in prostate cancer (PCa), which can be attributed to modulation of microRNAs (miRNAs/miRs). miRNAs/miRs are small non‐coding RNAs that negatively regulate gene expression. We have analyzed differential miRNA expression in PCa cells treated with Res.

Methods and results:Using miRNA microarrays we found that 23 miRNAs were significantly down‐regulated and 28 miRNAs were significantly up‐regulated after Res treatment. The down‐regulated miRs included miR‐17‐92 and miR‐106ab clusters with well recognized oncogenic properties while the up‐regulated miRs included several tumor suppressors. Selected miRs were verified by qRT‐PCR, including miR‐17, miR‐20a, miR‐20b, miR‐106a and miR106b. Since these miRNAs target PTEN (phosphatase and tensin homolog deleted on chromosome 10), we performed Western blot to confirm up‐regulation of PTEN in PCa cells. In addition, using TargetScan database, we have identified putative mRNA targets for Res‐induced down‐ and up‐regulated miRs. Using a bioinformatics approach, we generated gene networks specifically altered by Res‐regulated miRNAs.

Conclusion:Our results indicate that the dietary compound Res may play an important role in prostate carcinogenesis through modulation of miRNA expression: Res down‐regulated oncogenic miRs and up‐regulated tumor suppressor miRs in PCa cells. Further in‐depth studies are necessary in order to fully recognize the beneficial miRNA‐mediated effects of Res in PCa.
Acrolein induced DNA damage, mutagenicity and effect on DNA repair
Authors: Tang Moon‐shong , Wang Hsiang‐tsui , Hu Yu , Chen Wei‐Sheng , Akao Makoto , Feng Zhaohui , Hu Wenwei
Published: June 2011

Acrolein (Acr) is a ubiquitous environmental contaminant; it also can be generated endogenously by lipid peroxidation. Acr contains a carbonyl group and an olefinic double bond; it can react with many cellular molecules including amino acids, proteins and nucleic acids. In this review article we focus on updating information regarding: (i) Acr‐induced DNA damage and methods of detection, (ii) repair of Acr–DNA damage, (iii) mutagenicity of Acr–DNA adducts, (iv) sequence specificity and methylation effect on Acr–DNA adduct formation and (v) the role of Acr in human cancer. We have found that Acr can inhibit DNA repair and induces mutagenic Acr–dG adducts and that the binding spectrum of Acr in the p53 gene in normal human bronchial epithelial cells is similar to the p53 mutational spectrum in lung cancer. Since Acr–DNA adduct has been identified in human lung tissue and Acr causes bladder cancer in human and rat models, we conclude that Acr is a major lung and bladder carcinogen, and its carcinogenicity arises via induction of DNA damage and inhibition of DNA repair.
Assessment of cell infiltration in myocardial infarction: A dose‐dependent study using micrometer‐sized iron oxide particles
Authors: Yang Yidong , Liu Jimei , Yang Yuhui , Cho Sang Hyun , Hu Tom C.‐C.
Published: June 2011

Myocardial infarction (MI) is a leading cause of death and disabilities. Inflammatory cells play a vital role in the process of postinfarction remodeling and repair. Inflammatory cell infiltration into the infarct site can be monitored using T‐weighted MRI following an intravenous administration of iron oxide particles. In this study, various doses of micrometer‐sized iron oxide particles (1.1–14.5 μg Fe/g body weight) were injected into the mouse blood stream before a surgical induction of MI. Cardiac MRIs were performed at 3, 7, 14, and 21 days postinfarction to monitor the signal attenuation at the infarct site. A dose‐dependent phenomenon of signal attenuation was observed at the infarct site, with a higher dose leading to a darker signal. The study suggests an optimal temporal window for monitoring iron oxide particles‐labeled inflammatory cell infiltration to the infarct site using MRI. The dose‐dependent signal attenuation also indicates an optimal iron oxide dose of approximately 9.1–14.5 μg Fe/g body weight. A lower dose cannot differentiate the signal attenuation, whereas a higher dose would cause significant artifacts. This iron oxide‐enhanced MRI technique can potentially be used to monitor cell migration and infiltration at the pathological site or to confirm any cellular response following some specific treatment strategies. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.
Enhancement and degradation of the R relaxation rate resulting from the encapsulation of magnetic particles with hydrophilic coatings
Authors: de Haan Hendrick W. , Paquet Chantal
Published: June 2011

The effects of including a hydrophilic coating around the particles are studied across a wide range of particle sizes by performing Monte Carlo simulations of protons diffusing through a system of magnetic particles. A physically realistic methodology of implementing the coating by cross boundary jump scaling and transition probabilities at the coating surface is developed. Using this formulation, the coating has three distinct impacts on the relaxation rate: an enhancement at small particle sizes, a degradation at intermediate particle sizes, and no effect at large particles sizes. These varied effects are reconciled with the underlying dephasing mechanisms by using the concept of a full dephasing zone to present a physical picture of the dephasing process with and without the coating for all sizes. The enhancement at small particle sizes is studied systemically to demonstrate the existence of an optimal ratio of diffusion coefficients inside/outside the coating to achieve maximal increase in the relaxation rate. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.
B Phase mapping at 7 T and its application for in vivo electrical conductivity mapping
Authors: van Lier Astrid L.H.M.W. , Brunner David O. , Pruessmann Klaas P. , Klomp Dennis W.J. , Luijten Peter R. , Lagendijk Jan J.W. , van den Berg Cornelis A.T.
Published: June 2011

In this study, a new approach to measure local electrical conductivity in tissue is presented, which is based on the propagating B phase and the homogeneous Helmholtz equation. This new MRI technique might open future opportunities for tumor and lesion characterization based on conductivity differences, while it may also find application in radio frequency safety assessment. Prerequisites for conductivity mapping using only the B phase (instead of the complex B field) are addressed. Furthermore it was found that the B phase can be derived directly from the measurable transceive phase arg(B B) in the head. Validation for a human head excited by a 7 T‐birdcage coil using simulations and measurements showed that it is possible to measure in vivo conductivity patterns in the brain using B phase information only. Conductivity contrast between different brain tissues is clearly observed. The measured mean values for white matter, gray matter and cerebrospinal fluid differed 54%, 26%, and −13% respectively from literature values. The proposed method for B phase measurements is very suited for in vivo applications, as the measurement is short (less than a minute per imaged slice) and exposes the patient to low RF power, contrary to earlier proposed approaches. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.
Glioma cell density in a rat gene therapy model gauged by water relaxation rate along a fictitious magnetic field
Authors: Liimatainen Timo , Sierra Alejandra , Hanson Timothy , Sorce Dennis J. , Ylä‐Herttuala Seppo , Garwood Michael , Michaeli Shalom , Gröhn Olli
Published: June 2011

Longitudinal and transverse rotating‐frame relaxation time constants, T1ρ and T2ρ, have previously been successfully applied to detect gene therapy responses and acute stroke in animal models. Those experiments were performed with continuous‐wave irradiation or with frequency‐modulated pulses operating in an adiabatic regime. The technique called Relaxation Along a Fictitious Field (RAFF) is a recent extension of frequency‐modulated rotating‐frame relaxation methods. In RAFF, spin locking takes place along a fictitious magnetic field, and the decay rate is a function of both T1ρ and T2ρ processes. In this work, the time constant characterizing water relaxation with RAFF (TRAFF) was evaluated for its utility as a marker of response to gene therapy in a rat glioma model. To investigate the sensitivity to early treatment response, we measured several rotating‐frame and free‐precession relaxation time constants and the water apparent diffusion coefficients, and these were compared with histological cell counts in 8 days of treated and control groups of animals. TRAFF was the only parameter exhibiting significant association with cell density in three different tumor regions (border, intermediate, and core tissues). These results indicate that TRAFF may provide a marker to identify tumors responding to treatment. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Selective excitation of two‐dimensional arbitrarily shaped voxels with parallel excitation in spectroscopy
Authors: Snyder Jeff , Haas Martin , Hennig Jürgen , Zaitsev Maxim
Published: June 2011

Parallel excitation is being studied intensively for applications in MR imaging and in particular for selecting arbitrary shapes as regions of interest. In this work, parallel excitation was applied to arbitrarily shaped voxel selection in spectroscopy and investigated for different excitation k‐space trajectories (radial, rectilinear, and spiral) and acceleration factors. Each trajectory was segmented into multiple excitations to increase the overall bandwidth during target selection. Acceleration by parallel excitation was used to decrease the number of segments. Evaluation of spatial and spectral localization of the target of interest was performed in simulation and phantom experiments, and was compared with the point resolved spectroscopy (PRESS) experiment with standard voxels. The selective excitation experiments demonstrated excellent spatial localization and a broad frequency response, although PRESS was superior in direct comparisons with respect to signal‐to‐noise ratio (SNR) and outer volume suppression. Extensive SNR variation was observed dependent on trajectory (8%–90%), with the preferred radial case producing approximately 40%–60% SNR of the PRESS case. Accelerated trajectories at R = 4 provided comparable artifact signal and target excitation accuracy compared with their nonaccelerated counterparts; however, further acceleration (R = 8) resulted in increased artifact (33% increase at R = 8). Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.
Non‐contrast‐enhanced vascular magnetic resonance imaging using flow‐dependent preparation with subtraction
Authors: Priest Andrew N. , Graves Martin J. , Lomas David J.
Published: June 2011

Recent concerns over contrast agent safety have encouraged new developments in non‐contrast‐enhanced vascular imaging techniques. This work investigates the potential for imaging both arteries and veins with vascular anatomy by nonenhanced static subtraction angiography (VANESSA), a method using controllable flow suppression together with subtraction of bright‐ and dark‐blood images. The lower legs of eight healthy volunteers and three patients were imaged using a modified motion‐sensitized driven equilibrium preparation, with three‐dimensional balanced steady‐state free precession readout. The vascular signal decreased with increasing motion‐suppression gradient amplitude, and was suppressed when the velocity‐encoding parameter was (approximately) less than the measured flow velocity. Selected pairs of images were subtracted to depict vessels with either fast flow (e.g. arteries), slow flow (e.g. veins), or both. Several methodological modifications improved image quality and reduced the background signal from static tissues. Subjectively assessed image quality in volunteers was rated as excellent for 56/64 arterial segments, and good or excellent for 35/64 veins. In conclusion, VANESSA enables rapid non‐contrast‐enhanced imaging of arteries and veins, combining information on both morphology and flow. This study demonstrates good technical performance in volunteers and evaluation in patients with vascular disease is warranted. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.
Phase‐based regional oxygen metabolism (PROM) using MRI
Authors: Fan Audrey P. , Benner Thomas , Bolar Divya S. , Rosen Bruce R. , Adalsteinsson Elfar
Published: June 2011

Venous oxygen saturation (Yv) in cerebral veins and the cerebral metabolic rate of oxygen (CMRO2) are important indicators for brain function and disease. Although MRI has been used for global measurements of these parameters, currently there is no recognized technique to quantify regional Yv and CMRO2 using noninvasive imaging. This article proposes a technique to quantify CMRO2 from independent MRI estimates of Yv and cerebral blood flow. The approach uses standard gradient‐echo and arterial spin labeling acquisitions to make these measurements. Using MR susceptometry on gradient‐echo phase images, Yv was quantified for candidate vein segments in gray matter that approximate a long cylinder parallel to the main magnetic field. Local cerebral blood flow for the identified vessel was determined from a corresponding region in the arterial spin labeling perfusion map. Fick's principle of arteriovenous difference was then used to quantify CMRO2 locally around each vessel. Application of this method in young, healthy subjects provided gray matter averages of 59.6% ± 2.3% for Yv, 51.7 ± 6.4 mL/100 g/min for cerebral blood flow, and 158 ± 18 μmol/100 g/min for CMRO2 (mean ± SD, n = 12), which is consistent with values previously reported by positron emission tomography and MRI. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.
Rapid B1 mapping using orthogonal, equal‐amplitude radio‐frequency pulses
Authors: Chang Yulin V.
Published: June 2011

We present a new phase‐based method for mapping the amplitude of the radio‐frequency field (B1) of a transmitter coil in three‐dimension. This method exploits the noncommutation relation between rotations about orthogonal axes. Our implementation of this principle in the current work results in a simple relation between the phase of the final magnetization and the flip angle (FA). In this study, we focus on FAs less than 90°. Our method is rapid and easy to implement compared with the existing B1 mapping schemes. The mapping sequence can be simply obtained by adding to a regular three‐dimensional gradient‐echo sequence a magnetization preparation radio‐frequency pulse of the same FA but orthogonal in phase to the excitation radio‐frequency pulse. This method is demonstrated capable of generating reliable maps of the B1 field within 1 min using FAs no larger than 60°. We show that it is robust against T1, small chemical shift, and mild background inhomogeneity. This method may especially be suitable for B1 mapping in situations (e.g., long‐T1 and hyperpolarized‐gas imaging) where magnitude‐based methods are not readily applicable. A noise calculation of the FA map using this method is also presented. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.
Effect of intercompartmental water exchange on the apparent myelin water fraction in multiexponential T2 measurements of rat spinal cord
Authors: Harkins Kevin D. , Dula Adrienne N. , Does Mark D.
Published: June 2011

The myelin water fraction has been used as a quantitative measure of the amount of myelin present in tissue. However, recent work has suggested that intercompartmental exchange of water between myelin and nonmyelin compartments may cause the myelin water fraction to underestimate the true myelin content of tissue. In this work, multiexponential T2 experiments were performed in vivo within the rat spinal cord, and a wide variation of the myelin water fraction (10–35%) was measured within four rat spinal cord tracts with similar myelin content. A numerical simulation based upon segmented histology images was used to quantitatively account for T2 variations between tracts. The model predicts that a difference in exchange between the four spinal cord tracts, mediated by a difference in the average axon radius and myelin thickness, is sufficient to account for the variation in myelin water fraction measured in vivo. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.