bluuebunny/crossref_metadata_2025 huggingface dataset:
Parallel Pathways and Free‐Energy Landscapes for Enzymatic Hydride Transfer Probed by Hydrostatic Pressure
Authors: Pudney Christopher R. , McGrory Tom , Lafite Pierre , Pang Jiayun , Hay Sam , Leys David , Sutcliffe Michael J. , Scrutton Nigel S.
Published: April 2009

Mutation of an active‐site residue in morphinone reductase leads to a conformationally rich landscape that enhances the rate of hydride transfer from NADH to FMN at standard pressure (1 bar). Increasing the pressure causes interconversion between different conformational substates in the mutant enzyme. While high pressure reduces the donor–acceptor distance in the wild‐type enzyme, increased conformational freedom “dampens” its effect in the mutant.

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We show that hydride transfer from NADH to FMN catalysed by the N189A mutant of morphinone reductase occurs along parallel “chemical” pathways in a conformationally rich free‐energy landscape. We have developed experimental kinetic and spectroscopic tools by using hydrostatic pressure to explore this free‐energy landscape. The crystal structure of the N189A mutant enzyme in complex with the unreactive coenzyme analogue NADH4 indicates that the nicotinamide moiety of the analogue is conformationally less restrained than the corresponding structure of the wild‐type NADH4 complex. This increased degree of conformational freedom in the N189A enzyme gives rise to the concept of multiple reactive configurations (MRCs), and we show that the relative population of these states across the free‐energy landscape can be perturbed experimentally as a function of pressure. Specifically, the amplitudes of individual kinetic phases that were observed in stopped‐flow studies of the hydride transfer reaction are sensitive to pressure; this indicates that pressure drives an altered distribution across the energy landscape. We show by absorbance spectroscopy that the loss of charge‐transfer character of the enzyme–coenzyme complex is attributed to the altered population of MRCs on the landscape. The existence of a conformationally rich landscape in the N189A mutant is supported by molecular dynamics simulations at low and high pressure. The work provides firm experimental and computational support for the existence of parallel pathways arising from multiple conformational states of the enzyme–coenzyme complex. Hydrostatic pressure is a powerful and general probe of multidimensional energy landscapes that can be used to analyse experimentally parallel pathways for enzyme‐catalysed reactions. We suggest that this is especially the case following directed mutation of a protein, which can lead to increased population of reactant states that are essentially inaccessible in the free‐energy landscape of wild‐type enzyme.
The Folly of Protobranching: Turning Repulsive Interactions into Attractive Ones and Rewriting the Strain/Stabilization Energies of Organic Chemistry
Authors: Gronert Scott
Published: April 2009

Strain/stabilization energies: Recently it has been argued that the accepted strain/stabilization energies of fundamental species are incorrect because they ignore the effects of protobranching. Here it is shown that the basic premise of the protobranching mechanism is unlikely and that conventional strain/stabilization energies are more chemically important than those from the protobranching approach.

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Controlling the Formation of Cyanine Dye H‐ and J‐Aggregates with Cucurbituril Hosts in the Presence of Anionic Polyelectrolytes
Authors: Gadde Suresh , Batchelor Elizabeth K. , Kaifer Angel E.
Published: April 2009

Controlling aggregation: The formation of H‐ and J‐aggregates by cyanine dyes can be significantly enhanced by poly(styrenesulfonate) and further controlled though host–guest complexation with the cucurbit[7]uril host (see picture).

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The presence of anionic polyelectrolytes enhances the tendency of cationic cyanine dyes to form aggregates in aqueous media. In this work we investigate the interactions between two cyanine dyes, pseudoisocyanine (PIC) and pinacyanol (PIN), with polystyrenesulfonate (PSS) as the key additive to develop J‐ and H‐aggregates. We also take advantage of the binding properties of the cucurbit[7]uril (CB7) host to control formation of these aggregates through its host–guest interactions with the dye molecules. UV/Vis absorption spectroscopic studies clearly demonstrate the PSS‐enhanced formation of J‐aggregates in the case of PIC and H‐aggregates in the case of PIN. Electrostatic interactions between the cyanine dye molecules and the polyelectrolyte chains assist the formation of J‐ or H‐aggregates at very low dye concentrations (ca. 10 μM). Optimum development of dye aggregates was observed at a sulfonate/dye molar ratio of about 3:1. Departures from this stoichiometric ratio seem to perturb the optimal aggregate structure. Furthermore, the presence of CB7 was found to effectively disrupt the interactions responsible for dye aggregation. Thus, CB7 completely disrupts the J‐aggregates formed by PIC and the H‐aggregates (as well as lower concentrations of J‐aggregates) formed by PIN. UV/Vis and emission spectroscopic studies clearly indicate that binding of CB7 to both dye molecules removes them from the aggregate structures. Our spectroscopic data clearly indicate that regulation of the relative molar ratios of dye, CB7 host, and polyelectrolyte sulfonate groups leads to a quantitative control of dye aggregation, yielding variable amounts of PIC J‐ and PIN H‐aggregates in these solutions.
The Laulimalide Family: Total Synthesis and Biological Evaluation of Neolaulimalide, Isolaulimalide, Laulimalide and a Nonnatural Analogue
Authors: Gollner Andreas , Altmann Karl‐Heinz , Gertsch Jürg , Mulzer Johann
Published: April 2009

A sensitive family: The first total synthesis of the antitumor agents neolaulimalide and isolaulimalide as well as a highly efficient route to laulimalide is described. A Kulinkovich reaction followed by a cyclopropyl–allyl rearrangement is used to install the exo‐methylene group. The cytotoxicity of neolaulimalide could be confirmed for the first time since its original isolation and it could be shown that it induces tubulin polymerization as efficiently as laulimalide.

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We herein describe in full detail the first total synthesis of the antitumor agents neolaulimalide and isolaulimalide as well as a highly efficient route to laulimalide. A Kulinkovich reaction followed by a cyclopropyl–allyl rearrangement is used to install the exo‐methylene group. The C2–C16 aldehyde fragment is coupled with the C17–C28 sulfone fragments by a highly (E)‐selective Julia–Lythgoe–Kocienski olefination to deliver the key intermediates of all three syntheses. Various conditions for the Yamaguchi macrolactonization are applied to close the individual macrocycles. Finally a carefully elaborated endgame was developed to solve the problem of acyl migration in the case of neolaulimalide. All compounds were tested against several cell lines. The cytotoxicity of neolaulimalide could be confirmed for the first time since its original isolation and it could be shown that it induces tubulin polymerization as efficiently as laulimalide.
Catalytic Asymmetric Baeyer–Villiger Oxidation in Water by Using PtII Catalysts and Hydrogen Peroxide: Supramolecular Control of Enantioselectivity
Authors: Cavarzan Alessandra , Bianchini Giulio , Sgarbossa Paolo , Lefort Laurent , Gladiali Serafino , Scarso Alessandro , Strukul Giorgio
Published: April 2009

The enantioselective Baeyer–Villiger oxidation of cyclic ketones is a challenging reaction, especially when using environmentally friendly oxidants. The reaction was carried out in water by using soft Lewis acid PtII complexes that have chiral diphosphines as well as monophosphines. Addition of a surfactant is crucial, which leads to the formation of micelles that act as nanoreactors in which the substrate and catalyst encounter each other in an ordered medium that in several cases positively influences both the conversion and the selectivity of the reactions. This is due to the combination of the hydrophobic effect (which confines the components of the reaction in the micelles), together with supramolecular interactions between the partners within the ordered palisade provided by the alkyl chains of the surfactant. For the oxidation of meso‐cyclobutanones, addition of surfactant allowed the reaction to proceed in high yields and the enantiometic excess (ee; 56 %) was higher than in organic solvents. Subsequent extension to meso‐cyclohexanones resulted in a general decrease in yields but an enhancement of enantioselectivity (ee up to 92 %) moving from organic to water–surfactant media, regardless of the substrate or the catalyst employed. Different behaviour was observed with chiral cyclobutanones 7 and 10: with 7 the best catalyst was 1 g, whereas with the larger substrate, 10, complexes 1 a–b performed better in terms of enantioselectivity. Each combination of substrate, catalyst and surfactant is a new system and supramolecular reciprocal interactions together with the hydrophobic character of the counterparts play crucial roles. The asymmetric Baeyer–Villiger oxidation in water catalyzed by 1 a–h in the presence of micelles is a viable reaction that often benefits from the hydrophobic effect, leading to substantial increases in enantioselectivity.
Low‐Molecular‐Weight Dendrons for DNA Binding and Release by Reduction‐Triggered Degradation of Multivalent Interactions
Authors: Kostiainen Mauri A. , Rosilo Henna
Published: April 2009

Losing the grip: The synthesis of multivalent low‐molecular‐weight dendrons with lysine branching units coupled to disulfide‐linked spermine surface groups is described. It is furthermore demonstrated that the dendrons bind DNA with good affinity (see image), but are also able to release the DNA in a reductive environment.

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Exploring adoption difficulties in mobile banking services
Authors: Yang Ann Shawing
Published: April 2009

Factors associated with adopting and resisting mobile banking technologies were investigated among university students in Taiwan. Adoption factors included the belief that mobile banking helps fulfill personal banking needs, provides location‐free conveniences, and is cost effective. The primary factors associated with resistance included concerns over system configuration security and basic fees for mobile banking web connections. The theoretical and applied implications of these findings are discussed. Copyright © 2009 ASAC. Published by John Wiley & Sons, Ltd.
Centriole assembly in CHO cells expressing Plk4/SAS6/SAS4 is similar to centriogenesis in ciliated epithelial cells
Authors: Kuriyama Ryoko
Published: April 2009

Centriole assembly is initiated by Plk4, a Polo‐like kinase 4, which causes the recruitment of downstream regulators, such as SAS6 and SAS4, to a nascent centriole. Simultaneous expression of Plk4, SAS6 and SAS4 in CHO cells resulted in the formation of massive fibrogranular aggregates of various sizes and shapes. These aggregates were surrounded by dense particles of about 70 nm in diameter, similar to the centriolar satellite that has been observed around the centrosome in normal cycling cells. Within the fibrillar material, ring‐like structures appeared and eventually differentiated into centrioles by association with short microtubule bundles. Centrioles were also assembled around a parent centriole in a cluster, a configuration that has been described as a “flower structure” formation [Kleylein‐Sohn et al.,2007]. This pattern of centriole duplication is reminiscent of the arrangement of new centrioles induced in normal ciliated trachea/oviduct cells by the centriole‐dependent pathway, which was reported several decades ago [Sorokin,1968; Anderson and Brenner,1971; Dirksen,1971]. Prior to the production of hundreds of centrioles, these differentiating epithelial cells were also shown to induce a dense filamentous material similar to that detected in transfected CHO cells. These results suggest a common mechanism of centriole assembly regulated by Plk4 in both transfected cycling cells and normal ciliated epithelial cells undergoing differentiation. Cell Motil. Cytoskeleton 2009. © 2009 Wiley‐Liss, Inc.
Dasatinib early intervention after cytogenetic or hematologic resistance to imatinib in patients with chronic myeloid leukemia
Authors: Quintás‐Cardama Alfonso , Cortes Jorge E. , O'Brien Susan , Ravandi Farhad , Borthakur Gautam , Liu David , Bleickardt Eric , Chen Tai‐Tsang , Kantarjian Hagop M.
Published: April 2009

BACKGROUND:

Although many patients with chronic myeloid leukemia (CML) respond well to imatinib therapy, a significant proportion loses their initial response. Loss of response on imatinib is often because of BCR‐ABL mutations. Dasatinib is a 325‐fold more potent inhibitor of Bcr‐Abl than imatinib and has been associated with high rates of durable responses in patients with CML in chronic phase (CP) after imatinib failure.

METHODS:

To determine the optimal time for initiating dasatinib after loss of response on imatinib, data from dasatinib trials in CML‐CP were analyzed. Patients were grouped according to whether they received early intervention with dasatinib (ie, after cytogenetic recurrence on imatinib), rather than after both cytogenetic and hematologic recurrence.

RESULTS:

Overall, 72% of patients who received dasatinib after loss of a major cytogenetic response (MCyR) on imatinib achieved a complete cytogenetic response (CCyR) compared with 42% of patients who were treated after loss of both MCyR and complete hematologic response (CHR). Event‐free survival (EFS) also was higher after earlier dasatinib treatment (24‐month EFS rates: 89% after loss of MCyR on imatinib vs 29% after loss of both MCyR and CHR). Among patients who were treated after loss of CHR on imatinib with no prior MCyR, 26% achieved a CCyR with dasatinib, and the 24‐month EFS rate was 64%. In all 3 groups, CCyR rates were similar in patients with or without pre‐existing BCR‐ABL mutations.

CONCLUSIONS:

The results of the current study suggested that optimal outcomes are achieved when dasatinib is administered early after imatinib resistance. Cancer 2009. © 2009 American Cancer Society.
Ductal adenocarcinoma of the prostate
Authors: Tu Shi‐Ming , Lopez Adriana , Leibovici Dan , Bilen Mehmet A. , Evliyaoglu Ferhat , Aparicio Ana , Guo Charles C. , Kuban Deborah A. , Johnson Marcy M. , Pisters Louis L.
Published: April 2009

BACKGROUND:

Ductal or endometrioid adenocarcinoma of the prostate may be a subtype of prostate cancer that is amenable to aggressive local therapeutic strategies. The authors of this report investigated the clinical outcome of patients who had prostate ductal adenocarcinoma after primary radical prostatectomy or radiotherapy.

METHODS:

The clinical features of 108 patients with locally confined or advanced prostate ductal adenocarcinoma who had undergone primary radical prostatectomy (surgical group, n = 76 men) or no surgery (nonsurgical group, n = 32 men) were evaluated retrospectively. Clinical records were reviewed, and Gleason scores, clinical/pathologic stages, and preoperative prostate‐specific antigen levels were examined. The clinical features that were assessed included local recurrence, distant metastasis, and progression‐free and overall survival after primary therapy.

RESULTS:

In the surgical group, patients who had pure ductal prostate cancer survived longer (median, 13.8 years; 95% confidence interval [CI], from 13.8 years to not attained) than patients who had mixed ductal prostate cancer (median, 8.9 years; 95% CI, from 7.1 years to not attained; P = .05). In addition, the median time to local progression was shorter (2.8 years vs 4.9 years) and the median time to distant metastasis was longer (3.9 years vs 2.0 years) for patients who had pure ductal adenocarcinoma than for patients who had mixed ductal adenocarcinoma of the prostate after surgery, respectively.

CONCLUSIONS:

The results of this preliminary study suggested that pure ductal prostate adenocarcinoma tends to pursue an indolent clinical course and poses an increased risk for local recurrence. Local control (particularly prostatectomy) may improve the clinical outcome of patients with pure prostate ductal adenocarcinoma. These results need to be confirmed in prospective studies. Cancer 2009. © 2009 American Cancer Society.
Red‐ and Blue‐Shifted Hydrogen Bonds in theCis–TransNoncyclic Formic Acid Dimer
Authors: Zhou Pan‐Pan , Qiu Wen‐Yuan
Published: April 2009

Thecis–transnoncyclic formic acid dimer was studied by means of MP2 method with 6‐31G(d,p), 6‐31+G(d,p) and 6‐311+G(d,p) basis sets. It exhibits simultaneously red‐shifted OH⋅⋅⋅O and blue‐shifted CH⋅⋅⋅O hydrogen bonds. AIM and NBO analyses are performed at the MP2/6‐31+G(d,p) level to explore their properties and origins. AIM analysis provides the evidence that the OH bond becomes weaker and the CH bond becomes stronger upon the hydrogen bond formations. Intermolecular and intramolecular hyperconjugations have important influence on the electron densities in the XH (X=O, C) σ bonding orbital and its σ* antibonding orbital. The electron densities in the two orbitals are closely connected with the XH (X=O, C) bond length, and they are used to quantitatively estimate the bond length variation. The larger amount of charge transfer in the red‐shifted OH⋅⋅⋅O hydrogen bond is due to its favorable H⋅⋅⋅O electron channel, whereas the H⋅⋅⋅O electron channel in the blue‐shifted CH⋅⋅⋅O hydrogen bond is weaker. Structural reorganization effects shorten the CH bond by approximately 30 % when compared to the CH bond contraction upon the dimerization. Strikingly, it leads to a small elongation and a slight red shift of the OH bond. Both rehybridization and repolarization result in the XH (X=O, C) bond contraction, but their effects on the OH bond do not hold a dominant position. The hydrogen‐bonding processes go through the electrostatic attractions, van der Waals interactions, charge‐transfer interactions, hydrogen‐bonding interactions and electrostatic repulsions. Electrostatic attractions are of great importance on the origin of the red‐shifted OH⋅⋅⋅O hydrogen bond, especially the strong Hδ+⋅⋅⋅Oδ−attraction. For the blue‐shifted CH⋅⋅⋅O hydrogen bond, the considerable nucleus–nucleus repulsion between H and O atoms caused by the strong electrostatic attraction between C and O atoms is a possible reason for the CH bond contraction and its blue shift.
Raman Spectra of Poly(p‐phenylenevinylene)s with Fluorinated Vinylene Units: Evidence of Inter‐ring Distortion
Authors: Piacenza Manuel , Comoretto Davide , Burger Martin , Morandi Valentina , Marabelli Franco , Martinelli Carmella , Farinola Gianluca M. , Cardone Antonio , Gigli Giuseppe , Della Sala Fabio
Published: April 2009

Ring the changes: Experimental Raman spectra of fluorinated and non‐fluorinated polyphenylenevinylenes are assigned according to quantum chemical calculations for oligomer model systems (see picture). Characteristic differences in the spectra can be traced back to strong inter‐ring distortion of the fluorinated compounds.

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The Raman spectrum of poly{2‐methoxy‐5‐[(2‐ethylhexyl)oxy]‐1,4‐phenylenedifluorovinylene} (MEH‐PPDFV) is reported and compared with that of a well‐known non‐fluorinated reference polymer, namely poly{2‐methoxy‐5‐[(2‐ethylhexyl)oxy]‐1,4‐phenylenevinylene} (MEH‐PPV). The Raman spectra of both polymers are assigned on the basis of density functional theory calculations of the corresponding oligomers. The main differences between vinylene fluorinated and non‐fluorinated structures deal with the intensity, frequency shift and broadening of CC vinylene stretching. Additional differences concern the relative intensities of CC phenylene and vinylene stretching as well as the deformation modes in the range 1250–1350 cm−1. It is shown that these effects are due to the larger distortion from planarity of the fluorinated polymer, compared with the non‐fluorinated counterpart, induced by repulsive interactions between the fluorine atoms on the vinylene units and the oxygen atoms of the alkoxy groups on the aromatic rings.
Design and simulation of modular 2n to 1 quantum‐dot cellular automata (QCA) multiplexers
Authors: Mardiris Vassilios A. , Karafyllidis Ioannis G.
Published: April 2009

In this paper a novel design of a quantum‐dot cellular automata (QCA) 2 to 1 multiplexer is presented. The QCA circuit is simulated and its operation is analyzed. A modular design and simulation methodology is developed, which can be used to design 2n to 1 QCA multiplexers using the 2 to 1 QCA multiplexer as a building block. The design methodology is formulated in order to increase the circuit stability. Copyright © 2009 John Wiley & Sons, Ltd.
A robust certification service for highly dynamic MANET in emergency tasks
Authors: Ge M. , Lam K. Y. , Gollmann D. , Chung S. L. , Chang C. C. , Li J. B.
Published: April 2009

In emergency tasks, cross‐agency operations being carried out in disaster‐hit areas require some supporting communication system for command and control. Mobile Ad hoc Network (MANET) is a very suitable way to meet such communication requirements since it can function without any pre‐installed communication infrastructure. Owing to potential threats in the field environment and the unique features of MANET (e.g. the open nature of wireless links and the absence of security infrastructure), security of communications over MANET is a serious issue that is typically addressed by asymmetric cryptographic mechanisms. In this paper, we tackle issues critical to asymmetric key management in MANET, which almost invariably serves as a basis of security services in a network environment. To address the deficiencies of existing key management schemes, we propose the concept of mission‐specific certificate to manage public keys in our scenario. For issuance and/or revocation of mission‐specific certificate, a Mission‐specific Certificate Authority (MCA), which consists of a collection of server nodes to operate the threshold cryptographic scheme, is proposed. Furthermore, to cater for the occurrence of network partitioning, which is common in highly dynamic MANET, we propose a partition‐tolerant mechanism for MCA by introducing the notion of auxiliary server nodes. We discuss the security and performance of our scheme and show that our approach is a secure and partition‐tolerant mechanism can effectively improve availability of the MCA. Copyright © 2009 John Wiley & Sons, Ltd.
Cervical tuberculosis detection in Papanicolaou‐stained smear: Case report with review of literature
Authors: Gupta R. , Dey P. , Jain V. , Gupta N.
Published: April 2009

Genital tract tuberculosis is usually secondary to an extragenital tubercular focus. Cervical tuberculosis, however, is rare accounting for up to 3% of all genital tract diseases. The diagnosis of tuberculosis is usually established on multiple cervical biopsies followed by bacteriological confirmation. There are only a handful of reports on the diagnosis of tubercular cervicitis in cervical smears. We hereby report a case of cervical tuberculosis which was diagnosed on cervical smear. We also carried out a brief literature review of the cases diagnosed previously on cervical smear. Diagn. Cytopathol. 2009. © 2009 Wiley‐Liss, Inc.
Taurine supplementation enhances nutrient‐induced insulin secretion in pancreatic mice islets
Authors: Ribeiro Rosane A. , Bonfleur Maria L. , Amaral Andressa G. , Vanzela Emerielle C. , Rocco Silvana A. , Boschero Antonio C. , Carneiro Everardo M.
Published: April 2009

Background

Taurine (TAU), a naturally occurring sulfur‐containing amino acid, is found at high concentrations in plasma and mammalian tissues and regulates osmolarity, ion channel activity, and glucose homeostasis. Several reports have shown that physiological plasma TAU levels seem to be important for adequate beta (β)‐cell function and insulin action, since low concentrations of TAU in the plasma have been reported in the pre‐diabetic and diabetic states.

Methods

Glucose tolerance and insulin sensitivity were investigated in mice supplemented with 2% (w/v) TAU in their drinking water for 30 days, as well as the insulin secretion from isolated islets stimulated by glucose or L‐leucine.

Results

TAU‐supplemented mice demonstrated improved glucose tolerance and higher insulin sensitivity, compared to controls (CTL). In addition, their islets secreted more insulin in response to high concentrations of glucose and L‐leucine. L‐[U‐14C]leucine oxidation was higher in TAU than in CTL islets, whereas D‐[U‐14C]glucose oxidation, ATP levels, glucose transporter (GLUT) 2 and glucokinase (GCK) protein expressions were similar in both types of islets. The L‐type β2 subunit voltage‐sensitive Ca2+ channel protein, as well as 45Ca uptake, were significantly higher in TAU‐supplemented than CTL islets. In addition, islets from TAU‐supplemented mice secreted more glucagon than CTL islets at low glucose.

Conclusions

TAU supplementation improves glucose tolerance and insulin sensitivity in mice, as well as insulin secretion from isolated islets. The latter effect seems to be, at least in part, dependent on a better Ca2+ handling by the islets. Copyright © 2009 John Wiley & Sons, Ltd.
Advanced glycation end products in diabetic patients with optimized glycaemic control and their effects on endothelial reactivity: possible implications in venous graft failure
Authors: Chello Massimo , Spadaccio Cristiano , Lusini Mario , Covino Elvio , Blarzino Carla , De Marco Federico , Di Domenico Fabio , Coccia Raffaella
Published: April 2009

Background

Diabetic patients exhibit an increased risk of saphenous graft occlusion after coronary bypass. Advanced glycation end products (AGEs) are ubiquitous signalling proteins that are associated with vascular and neurological complication of diabetes. The aim of this study is to verify whether AGE levels may promote endothelial cell alterations responsible for vein graft failure.

Methods

Segments of saphenous vein were obtained from both normal people and diabetic patients (HbA1c < 6.0%) at the time of coronary surgery. Cultured endothelial cells were incubated in the absence/presence of AGEs (2 and 20 µM), and mRNA and protein for both receptor of AGEs (RAGE) and peroxisome proliferator‐activated receptors‐γ (PPAR‐γ) were analysed by real‐time polymerised chain reaction (PCR) and Western blot analysis. In the same fashion, the cell release of reactive oxygen species (ROS) was estimated in the absence/presence of AGEs by spectrofluorimetric analysis. Finally, neutrophil‐endothelial adhesion was evaluated in saphenous vein segments with and without the addition of AGEs.

Results

AGEs activated in a dose‐dependent manner the expression of RAGE and inhibited PPAR‐γ expression in endothelial cells as testified by both reverse transcription‐PCR (RT‐PCR) and Western blot analysis. Stimulation of cultured endothelial cells with AGEs significantly enhanced intracellular ROS formation in a dose‐dependent manner. Finally, neutrophil‐endothelial adhesion was significantly increased after incubation of control veins with AGEs.

Conclusions

These findings indicate that even in diabetic patients with HbA1c < 6.0%, elevated serum levels of AGE determine a sort of a pro‐thrombotic state, providing a common mechanism that could explain the increased rate of vein graft occlusion in this population. Copyright © 2009 John Wiley & Sons, Ltd.
Extended‐release niacin decreases serum fetuin‐A concentrations in individuals with metabolic syndrome
Authors: Kaushik Shalini V. , Plaisance Eric P. , Kim Teayoun , Huang Edmond Y. , Mahurin A. Jack , Grandjean Peter W. , Mathews Suresh T.
Published: April 2009

Background

Fetuin‐A, a liver‐secreted phosphoprotein and physiological inhibitor of insulin receptor tyrosine kinase, is associated with insulin resistance, metabolic syndrome (MetS), and an increased risk for type 2 diabetes. However, studies on the modulation of circulating levels of fetuin‐A are limited. The goal of this study was to determine the effect of niacin administration on serum total‐ and phosphorylated fetuin‐A (phosphofetuin‐A) concentrations in individuals with MetS and correlate with changes in serum lipids, insulin sensitivity, and markers of inflammation.

Methods

Fifteen sedentary, obese, male participants, who met the National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) criteria for MetS, were treated with extended‐release niacin (Niaspan) for 6 weeks. Blood samples were obtained before and after treatment with niacin.

Results

Serum fetuin‐A and phosphofetuin‐A concentrations were decreased following niacin administration (p < 0.005). Changes in fetuin‐A concentrations were correlated with changes in triglyceride (r = 0.62, p = 0.01) and C‐reactive protein (CRP) concentrations (r = 0.58, p < 0.05) after niacin treatment. Changes in high‐density lipoproteins (HDL)‐cholesterol following niacin intervention were negatively correlated with changes in serum fetuin‐A (p < 0.05) and phosphofetuin‐A concentrations (p < 0.05). Serum cortisol levels were significantly elevated after niacin administration.

Conclusions

Niacin treatment lowers serum total‐ and phosphofetuin‐A concentrations in individuals with MetS, and these changes correlate with the beneficial changes in serum lipids. Because niacin is known to induce insulin resistance, these findings suggest that fetuin‐A may not be a mediator of niacin‐induced insulin resistance but it may blunt the insulin resistance induced by niacin by decreasing its circulating concentrations. Copyright © 2009 John Wiley & Sons, Ltd.
DNAX accessory molecule‐1 (CD226) promotes human hepatocellular carcinoma cell lysis by Vγ9Vδ2 T cells
Authors: Toutirais Olivier , Cabillic Florian , Le Friec Gaëlle , Salot Samuel , Loyer Pascal , Le Gallo Matthieu , Desille Mireille , de La Pintière Cécile Thomas , Daniel Pascale , Bouet Françoise , Catros Véronique
Published: April 2009

Human Vγ9Vδ2 T lymphocytes can be activated by nonpeptidic antigens such as the mevalonate pathway‐derived isopentenyl pyrophosphate or synthetic phosphoantigen such as bromohydrin pyrophosphate. They display a strong cytotoxic activity against several tumor types, including hepatocellular carcinoma (HCC). Little is known about the mechanisms underlying Vγ9Vδ2 T‐cell recognition of tumor cells, but there is strong evidence that activating NK receptors play a role in γδ T‐cell cytotoxicity. In this study, we showed that the two NK receptors DNAX accessory molecule‐1 (DNAM‐1) and CD96 were expressed by Vγ9Vδ2 T cells. The ligands Nectin‐like‐5 specific of both DNAM‐1 and CD96, and also Nectin‐2, an additional ligand of DNAM‐1, were present on all HCC cell lines analyzed. Furthermore, we demonstrated by mAb‐mediated masking experiments that cytotoxicity against HCC cells as well as IFN‐γ production in γδ T cells were dependent on DNAM‐1. Our experiments indicated that Nectin‐like‐5 but not Nectin‐2 was involved in DNAM‐1‐dependent γδ T‐cell functions. We did not reveal a role for CD96 in the killing of HCC cells. Finally, we showed by combined mAb‐mediated blockade that DNAM‐1 and NKG2D could cooperate in the cell lysis of HCC.
Shine a light: Imaging the immune system
Authors: Sarris Milka , Betz Alexander G.
Published: April 2009

Intra vital microscopy and whole‐body imaging promise to revolutionize how we study the immune system. They compel by the intrinsic beauty of the images obtained and the undeniable direct biological relevance of the observations. However, it is important to remember that in many cases, fundamental insights into the underlying biological processes have already been obtained using ex vivo reductionist approaches. Indeed, it is likely that with the advent of microfluidics, new and exciting avenues will open up for ex vivo experimentation. Here, we give a brief but comprehensive overview of the various imaging techniques available, their relative strengths and shortcomings and how these tools have been used to get us to where we are today. The challenge for the future will be to apply the most suitable technology and to integrate the findings across various imaging disciplines to build a unified, comprehensive “big picture” of the immune system.
Clonal dissection of the human memory B‐cell repertoire following infection and vaccination
Authors: Pinna Debora , Corti Davide , Jarrossay David , Sallusto Federica , Lanzavecchia Antonio
Published: April 2009

The analysis of the human memory B‐cell repertoire is of both fundamental and practical significance. We developed a simple method for the selective activation of memory B cells in total fresh or frozen PBMC using a combination of R848 and IL‐2. In these conditions, 30–40% of memory B cells generated clones producing on average 200 ng IgG in 10 days. This method was used to measure the frequency of antigen‐specific memory B cells as well as the fine specificity, cross‐reactivity and neutralizing activity of the secreted antibodies. Following influenza vaccination, specific B cells expanded dramatically, reaching up to 50% of total clonable memory B cells on day 14. Specific B‐cell expansions were detected also in individuals that did not show a significant serological response. Dynamic changes and persistence of B cells specific for a variety of pathogens were documented in serial PBMC samples collected over almost two decades. These results reveal novel aspects of memory B‐cell kinetics and provide a powerful tool to monitor immune responses following infection and vaccination.
Cover Picture: Eur. J. Immunol. 5/09
Authors: Scaldaferri Franco , Sans Miquel , Vetrano Stefania , Correale Carmen , Arena Vincenzo , Pagano Nico , Rando Giacomo , Romeo Fabio , Potenza Angelo E. , Repici Alessandro , Malesci Alberto , Danese Silvio
Published: April 2009

The cover image depicts human intestinal microvascular endothelial cells stained for ICAM‐1 after in vitro stimulation with the pro‐inflammatory cytokine TNF‐α. The image was taken from a recently‐published article by Scaldaferri et al. (Eur. J. Immunol. 2009. 39: 290–300), in which the authors demonstrate that stimulation with TNF‐α up‐regulates ICAM‐1 expression in human intestinal microvascular endothelial cells leading to increased recruitment of lymphocytes in the gut, a key pathogenic event in inflammatory bowel disease.
Structure, Spectral and Magnetic Properties of 3‐(p‐Pyridyl)‐1,5‐diphenylverdazyl (p‐PyV) and the Binuclear Copper(II) Radical Complex [Cu2(OCOCH3)4(p‐PyV)2]
Authors: Yakovenko Anastasiya V. , Kolotilov Sergey V. , Cador Olivier , Golhen Stéphane , Ouahab Lahcène , Pavlishchuk Vitaly V.
Published: April 2009

3‐(p‐Pyridyl)‐1,5‐diphenylverdazyl (p‐PyV) and its binuclear copper(II) complex [Cu2(OCOCH3)4(p‐PyV)2] have been synthesized and structurally characterized. The magnetic behavior of a single crystal of p‐PyV and [Cu2(OCOCH3)4(p‐PyV)2] have been studied by magnetic susceptibility measurements in the temperature range 2–300 K and by ESR spectroscopy. Data fitting for p‐PyV using the singlet‐triplet equilibrium model revealed the existence of antiferromagnetic interactions in the radical crystal lattice. The exchange interactions between the copper(II) ion and p‐PyV in Cu2(OCOCH3)4(p‐PyV)2 were found to be negligibly small compared to the strong intramolecular copper–copper antiferromagnetic interaction. Intermolecular antiferromagnetic coupling between p‐PyV molecules was detected in the crystal lattice of complex.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Structural Effects in Radical Clocks and Mechanisms of Grignard Reagent Formation: Special Effect of a Phenyl Substituent in a Radical Clock when the Crossroads of Selectivity is at a Metal/Solution Interface
Authors: Hazimeh Hassan , Mattalia Jean‐Marc , Marchi‐Delapierre Caroline , Kanoufi Frédéric , Combellas Catherine , Chanon Michel
Published: April 2009

A large class of radical clocks is based on the intramolecular trapping of a reactive radical by a suitably located unsaturated system. Depending on the substituents present on this unsaturated system, the rate of cyclisation may vary drastically. This property has been repeatedly used to diagnose the participation of very short‐lived radicals in the mechanisms of a wide variety of reactions. For reactions occurring in homogeneous solution, a phenyl substituent capable of stabilizing the radical formed during the act of trapping has been one of the most widely used tools of this type. During study of the mechanisms of formation of Grignard reagents – reactions that occur at the interface of the metal and the solution – the phenyl substituent displayed a specific new behaviour pattern. Besides its stabilizing role, it was also able to play the role of mediator in redox catalysis of electron transfer. In this case, the first events on the pathway to the Grignard reagents involve a cascade of three (one intermolecular followed by two intramolecular) electron transfers. Introduction of a p‐methoxy substituent on the phenyl ring, making the phenyl group a poorer electron acceptor, suppresses this specific second role. Applied to the mechanism of Grignard reagent formation, this p‐methoxy effect is consistent with a triggering mechanistic act of electron transfer from the metal to the aryl halide rather than with a concerted oxidative addition. A similar change in selectivity is observed when a p‐methoxy group is introduced onto a phenyl group that also bears a halogen, but its origin is different: this effect is associated with the shortening of the lifetime of the radical anion formed by the triggering electron transfer. These observations reemphasise our earlier proposals to use concepts originating from electrochemical kinetics to explain the selectivities of reactions occurring at metal/solution interfaces. This conjecture could possibly hold for any interface where the diffusion of reactive species plays a role in the settling of selectivity. These concepts emphasise the necessity to consider, for each reactive species, their average distance of diffusion away from the metal/solution interface.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Direct Access to L‐Azetidine‐2‐carboxylic Acid
Authors: Bouazaoui M'barek , Martinez Jean , Cavelier Florine
Published: April 2009

A straightforward synthesis of L‐azetidine‐2‐carboxylic acid is described, leading to both orthogonally protected versions or totally deprotected L‐Aze. The starting material is a commercially available aspartic acid derivative, whose chirality is conserved. The (2‐trimethylsilyl)ethanesulfonyl protecting group (SES) acts as a leaving group on the hydroxy function and serves as an activator for the amine function, which is the key‐step of the reaction. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Dihydroazulene Photoswitches: The First Synthetic Protocol for Functionalizing the Seven‐Membered Ring
Authors: Petersen Michael Åxman , Broman Søren Lindbæk , Kadziola Anders , Kilså Kristine , Nielsen Mogens Brøndsted
Published: April 2009

The first synthetic protocol for functionalizing the dihydroazulene (DHA) photoswitch in its seven‐membered ring has been developed. This protocol is based on regioselective bromination, followed by regioselective elimination of HBr, and finally a palladium‐catalyzed cross‐coupling reaction with a terminal alkyne. The position of functionalization (C‐7) was confirmed by X‐ray crystal structure analysis. Light‐induced ring opening of this compound to its vinylheptafulvene (VHF) isomer followed by thermal ring closure provides a mixture of two DHA regioisomers in a ratio that depends on the wavelength of irradiation and solvent polarity.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Role of a rheophyte in bench development on a sand‐bed river in southeast Australia
Authors: Erskine Wayne , Chalmers Anita , Keene Annabelle , Cheetham Michael , Bush Richard
Published: April 2009

Casuarina cunninghamiana Miq. is an important rheophytic tree in New South Wales, Australia because it is fast growing and can tolerate flood disturbance. Widden Brook is an active sand‐bed stream that has widened substantially since initial European settlement in the early 1800s and is characterized by high flood variability and multi‐decadal periods of alternating high and low flood frequency, called flood‐ and drought‐dominated regimes. Channel contraction by bench formation is currently occurring. Conversion of coarse‐grained point bars to benches is an important process of channel contraction. When point bars grow to a height where suspended sediment is first deposited to thicknesses of at least 50 mm by sub‐bankfull floods, rapid establishment of C. cunninghamiana occurs. As the trees grow they partially block bankside flows, thereby locally reducing flow velocity and inducing further deposition on the benches. Such synergistic relationships between bar height and inundation, fine‐grained sediment deposition, tree establishment and the development of a bankside low current velocity zone are fundamental for bench development. Size‐class frequency data demonstrate that C. cunninghamiana on the benches consists of pure even‐aged stands with most trees clustering near the average diameter. Two benches have similar size class frequency distributions but a third has significantly smaller trees. Recruitment on benches is episodic, may occur in areas open to grazing and is dependent on favourable conditions that allow tree survival. These favourable conditions include high seed availability, low levels of competition, deposition of fine sediments and adequate moisture for tree growth. Although C. cunninghamiana germinates on bars, seedlings are eliminated by prolonged inundation or flood scour and do not reach maturity. Recurring catastrophic floods or a sequence of large floods in rapid succession episodically destroy benches by substantial channel widening and initiate a new phase of bar and bench development. A conceptual model of the conversion of point bars to benches by thick mud deposition and C. cunninghamiana recruitment has been developed for sand‐bed streams draining similar sandstone catchments. Copyright © 2009 John Wiley & Sons, Ltd.
An empirical model of event scale cohesive bank profile evolution
Authors: Pizzuto Jim
Published: April 2009

The highly stochastic nature of riverbank erosion has driven the need for spatially explicit empirical models. Detailed bank profile surveys along a meander bend of the Brandywine Creek in Pennsylvania, USA, before and after 28 high flow events over a 2·5 year period are used to develop an empirical model of cohesive bank profile erosion. Two hundred and thirty‐six bank erosion observations are classified as hydraulic erosion or subaerial erosion. Threshold conditions required to initiate bank erosion cannot be defined based on field measurements. Using the near‐bank velocity and the number of freeze–thaw cycles as predictors, regression equations are derived for hydraulic erosion that specify the length, thickness, and location on the bank face of eroded blocks. An empirical discriminant function defines the critical geometry of overhang failures, and the volumes removed by overhang failures are computed using another regression equation. All the regression equations are significant, but have low correlation coefficients, suggesting that cohesive bank erosion has a strong stochastic component. Individual events typically remove small masses of soil (average volume 0·084 m3/m) a few centimeters thick (median = 0·057 m) and a few decimeters in length (median = 0·50 m) from the lower third of the bank. Hydraulic erosion is responsible for 87% of all erosion. When applied to three survey sites not used in its development, the profile model predicts the total volume of erosion with errors of 23%, 5% and 1%. Twenty‐four percent of computed erosion volumes for single events are within 50% of observed volumes at these three sites. Extending the approach to decadal timescales and to entire bends will require three‐dimensional observations of bank failure, and spatially and temporally explicit methods to account for the influence of individual large trees on bank failures and near‐bank hydraulic processes. Copyright © 2009 John Wiley & Sons, Ltd.
Functional status of men with the fragile X premutation, with and without the tremor/ataxia syndrome (FXTAS)
Authors: Brega Angela G. , Reynolds Ann , Bennett Rachael E. , Leehey Maureen A. , Bounds Lanee S. , Cogswell Jennifer B. , Hagerman Randi J. , Hagerman Paul J. , Grigsby Jim
Published: April 2009

Background

Fragile X‐associated tremor/ataxia syndrome (FXTAS), which occurs in some premutation carriers of the fragile X mental retardation 1 (FMR1) gene, is a neurodegenerative disorder characterized by action tremor, gait ataxia, and impaired executive cognitive functioning.

Objective

To evaluate the nature and severity of functional limitations among male carriers of the fragile X premutation, both with and without FXTAS.

Methods

Forty‐two subjects with FXTAS and 24 asymptomatic premutation carriers were compared to 32 control subjects on measures of physical functioning, activities of daily living (ADLs; e.g. eating, bathing), and instrumental activities of daily living (IADLs; e.g. shopping, managing medications). Ordinary least squares regression, controlling for age, education, medical comorbidity, and pain, was used to examine group differences in physical and functional performance.

Results

Men with FXTAS performed significantly worse than control subjects on all dependent measures, showing greater limitations in physical functioning, as well as ADL and IADL performance (p < 0.05). Subsequent analyses suggested that physical and functional impairments among men with FXTAS result largely from deficits in motor and executive functioning and that CGG repeat length is associated with functional impairment. Asymptomatic carriers of the fragile X premutation performed similarly to control subjects on all measures.

Conclusions

This study provides the first comprehensive evaluation of functional status among male premutation carriers. Although carriers without FXTAS performed similarly to control subjects, men with FXTAS showed evidence of significant physical and functional impairment, which appears to result largely from motor and executive deficits characteristic of the syndrome. Copyright © 2009 John Wiley & Sons, Ltd.
The effect of newer drugs on health spending: do they really increase the costs?
Authors: Ci̇van Abdülkadi̇r , Köksal Bülent
Published: April 2009

We analyze the influence of technological progress on pharmaceuticals on rising health expenditures using US State level panel data. Improvements in medical technology are believed to be partly responsible for rapidly rising health expenditures. Even if the technological progress in medicine improves health outcomes and life quality, it can also increase the expenditure on health care. Our findings suggest that newer drugs increase the spending on prescription drugs since they are usually more expensive than their predecessors. However, they lower the demand for other types of medical services, which causes the total spending to decline. We estimate that a 1‐year decrease in the average age of prescribed drugs causes per capita health expenditures to decrease by $45.43. The biggest decline occurs in spending on hospital care due to newer drugs. Copyright © 2009 John Wiley & Sons, Ltd.