bluuebunny/crossref_metadata_2025 huggingface dataset:
Dithiolate‐Bridged Fe‐Ni‐Fe Trinuclear Complexes Consisting of Fe(CO)3−n(CN)n (n=0, 1) Components Relevant to the Active Site of [NiFe] Hydrogenase
Authors: Pal Satyanarayan , Ohki Yasuhiro , Yoshikawa Teppei , Kuge Katsuaki , Tatsumi Kazuyuki
Published: January 2009

Step‐by‐step: A trinuclear Fe‐Ni‐Fe complex 1 was synthesized from the reaction of [Fe(CO)4I2] with Li2[Ni(norbornane‐exo‐2,3‐dithiolate)2]. The CO ligands in 1 were transformed into CN− upon treatment with −N(SiMe3)2, and the monocyanide complex 3 and the dicyanide complex 4 were obtained. Complexes 3 and 4 were found to react with protonic acids, whereas 1 is robust.

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A dithiolate‐bridged Fe‐Ni‐Fe trinuclear carbonyl complex [(CO)3Fe(μ‐ndt)Ni(μ‐ndt)Fe(CO)3] (1, ndt=norbornane‐exo‐2,3‐dithiolate) has been synthesized from the reaction of [Fe(CO)4I2] and Li2[Ni(ndt)2]. This reaction was found to occur with concomitant formation of a tetranuclear cluster [Ni3(μ‐ndt)4FeI] (2). Treatment of 1 with Na[N(SiMe3)2] transforms some of the CO ligands into CN−, and the monocyanide complex (PPh4)[(CO)2(CN)Fe(μ‐ndt)Ni(μ‐ndt)Fe(CO)3] (3) and the dicyanide complex (PPh4)2[(CO)2(CN)Fe(μ‐ndt)Ni(μ‐ndt)Fe(CO)2(CN)] (4) were isolated. X‐ray structural analyses of the trinuclear complexes revealed a Fe‐Ni‐Fe array in which the metal centers are connected by the ndt sulfur bridges and direct FeNi bonds. Hydrogen bonding between the CN ligand in 3 and cocrystallized ethanol was found in the solid‐state structure. The monocyanide complex 3 and dicyanide complex 4 reacted with acids such as HOTf or HCl generating insoluble materials, whereas complex 1 did not react.
Barocke Dachwerke: Konstruktion und Analyse des Tragverhaltens
Authors: Holzer Stefan M. , Köck Bernd
Published: January 2009

Konstruktion und Tragverhalten historischer Bauwerke haben schon öfter im Zentrum von Forschungsprojekten gestanden, zuletzt ganz besonders intensiv im Karlsruher DFG‐Sonderforschungsbereich 315 (Erhalten historisch bedeutsamer Bauwerke). Der hier vorliegende Beitrag ist einem Thema gewidmet, das bei allen diesen Forschungen bisher am Rande gestanden hat, nämlich den barocken Holzkonstruktionen. Die Autoren haben in den letzten Jahren eine große Anzahl barocker Dachwerke in Bayern untersucht, vorwiegend weitgespannte Kirchendächer. Der Bestand solcher Dächer gerade im Gebiet südlich der Donau ist nahezu unüberschaubar groß, und die statische Beurteilung und Ertüchtigung solcher Dächer stellt für den Bauingenieur eine sowohl praktisch und ökonomisch relevante als auch in der Modellbildung anspruchsvolle Aufgabe dar. Bei der Untersuchung der bayerischen Barockdächer hat es sich herausgestellt, dass die dort anzutreffenden Tragkonstruktionen in erheblichem Maße von den typischen mittelalterlichen Dachwerken oder auch von barocken Dachwerken anderer Regionen abweichen: Die barocken Dachtragwerke Süddeutschlands haben – in markantem Unterschied zum mittelalterlichen Dach mit seiner Reihung identischer, voneinander nahezu völlig unabhängiger Gespärre – ausgeprägte firstparallele Tragwirkung. Noch wichtiger – gerade auch im Hinblick auf notwendige Sanierungen – ist aber das äußerst häufige Fehlen eines Zugbandes in Form einer durchgehenden Anker‐ oder Zerrbalkenlage auf Höhe der Dachtraufe. Die oft weit in den Dachraum ragenden, meist aus Ziegeln gemauerten Gewölbe und Kuppeln machen komplizierte, vielfach statisch unbestimmte Konstruktionen zur Aufnahme der Schubkräfte der Gespärre notwendig. In diesem Beitrag werden typische Konstruktionsvarianten zur Lösung dieser barocken Aufgabe vorgestellt und deren Tragverhalten beleuchtet. Bei allen wichtigen Konstruktionsvarianten stellt sich heraus, dass diese Tragwerke bei der statischen Berechnung im Gegensatz zum klassischen Sparrendachwerk mit Zugband auf Traufenhöhe sehr sensibel auf Modellierungsannahmen reagieren, vor allem auf die angesetzten Steifigkeiten der Verbindungen und Auflager. Nichtlineare Modelle für Verbindungen (z. B. Berücksichtigung der herstellungs‐ und schwindbedingten Klaffungen) könnten einen wesentlichen Beitrag zum Verständnis des Lastabtrags und zum Nachweis der verbleibenden Standsicherheit solcher Tragwerke liefern (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A new assessment methodology for virtual reality surgical simulators
Authors: Bayona Sof ía , Fernández‐Arroyo José Manuel , Bayona Pilar , Pastor Luis
Published: January 2009

This paper presents an assessment methodology to validate surgical simulators which will help researchers in avoiding most common errors by providing a complete structured guide. The methodology organizes the questions depending on the validities they are related to, helping in objectives' definition and consistent hypothesis formulation. We will define the study depending on its purpose, time course and the study factor assignment, taking into account legal and ethical issues and choosing the population and sample size. If it is an experimental study, we will determine if there exist a control group and the operational definition of variables. We will avoid extraneous variables and make our study blind, establishing the final evaluation procedure, and stipulating actuation and observation protocols. A feasibility study will be performed before executing the pilot and final studies in which we will analyse the data as indicated by the statistical plan, obtaining our results and conclusions. We provide an example, applying the assessment methodology step by step to the evaluation of a virtual reality arthroscopy simulator with haptic feedback. Finally, possible experiments are proposed as well as a conscientious study of different alternatives for the final evaluation procedure, and an extended proposal of surgical competence assessment measures. Copyright © 2009 John Wiley & Sons, Ltd.
Spatial camera orientation control by rotation‐minimizing directed frames
Authors: Farouki Rida T. , Giannelli Carlotta
Published: January 2009

The use of rotation‐minimizing directed frames (RMDFs) for defining smoothly varying camera orientations along given spatial paths, in real or virtual environments, is proposed. A directed frame on a space curve${\bf r}(\xi)$is a varying orthonormal basis$({\bf o},{\bf p},{\bf q})$for ℝ3such that${\bf o}(\xi)={\bf r}(\xi)/|{\bf r}(\xi)|$coincides with the unit polar vector from the origin to each curve point, and such a frame is rotation‐minimizing if its angular velocity vector${\bf \omega}$maintains a vanishing component alongo. To facilitate computation of rotation‐minimizing directed frames, it is shown that the basic theory is equivalent to the established theory for rotation‐minimizing adapted frames—for which one frame vector coincides with the tangent${\bf t}(\xi)={\bf r}'(\xi)/|{\bf r}'(\xi)|$at each curve point—if one replaces the given space curve by its anti‐hodograph (i.e., indefinite integral). A family of polynomial curves on which RMDFs can be computed exactly by a rational function integration, the Pythagorean (P) curves, is also introduced, together with algorithms for their construction. Copyright © 2009 John Wiley & Sons, Ltd.
Formylglycine Aldehyde Tag—Protein Engineering through a Novel Post‐translational Modification
Authors: Frese Marc‐André , Dierks Thomas
Published: January 2009

Oxidation of a specific cysteine residue to Cα‐formylglycine is a novel post‐translational modification that is directed by a short recognition motif commonly found in pro‐ and eukaryotic sulfatases. As recently shown by C. Bertozzi and co‐workers, this system can be employed in protein engineering to equip proteins with genetically encoded aldehyde tags for site‐specific labeling, conjugation and immobilization.

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Electronic Structure and Absorption Spectra of Biferrocenyl and Bisfulvalenide Diiron Radical Cations: Detection and Assignment of New Low‐Energy Transitions
Authors: Warratz Ralf , Aboulfadl Hanane , Bally Thomas , Tuczek Felix
Published: January 2009

New transitions: Low‐energy electronic transitions have been detected spectroscopically in the FeII–FeIII mixed‐valent biferrocenyl radical cation, but are absent in the spectra of the neutral analogue. They have been assigned by time‐dependent DFT calculations (squares in figure). Analogous investigations were performed for the bisfulvalenide FeII–FeIII radical cation.

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UV‐visible/near‐IR (NIR)/mid‐IR (MIR) solution, solid‐state, and matrix‐isolation electronic absorption spectra of the FeII–FeIII mixed‐valent homobimetallic compounds biferrocenyl triiodide (1) and 1′,1′′′‐diethylbiferrocenyltriiodide (2) reveal the presence of a low‐energy transition in the MIR region that has not been reported before. The new absorption feature and the known NIR band are both assigned to intervalence charge‐transfer (IVCT) transitions. To obtain insight into the electronic structures of 1 and 2, DFT calculations with the BP86 functionals and different basis sets have been performed. Based on the molecular orbital scheme of cation 1, one band corresponds to the transition between the highest occupied d orbitals on the two iron centers, whereas the other one is assigned to a transition from a lower‐lying d orbital to the d orbital. For comparison, the doubly bridged bisfulvalenide diiron cation (3) has been investigated by optical absorption spectroscopy and DFT calculations. The experimental and theoretical results are discussed with respect to the degree of electron localization/delocalization in these systems.
Metal‐Dependent Reaction Tuning with Cyclopentylmetal Reagents: Application to the Asymmetric Synthesis of (+)‐α‐Conhydrine and (S)‐2‐Cyclopentyl‐2‐phenylglycolic Acid
Authors: Roy Siddharth , Sharma Anubha , Mula Soumyaditya , Chattopadhyay Subrata
Published: January 2009

Tuning in: The reaction of halocyclopentane organometallic reagents can be tuned by the choice of metal (see scheme). Cyclopentylmagnesium bromide reduces aldehydes and ketones to the corresponding alcohols. However, in the presence of ZnCl2, normal Grignard addition to the ketones gives tertiary alcohols with complete diastereoselectivity. These protocols were used in the asymmetric synthesis of two medicinally important compounds.

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The reaction profile of the cyclopentyl organometallic reagents with the aliphatic ketones can be tuned to reduction or addition by changing the metal atom. Cyclopentylmagnesium bromide (CPMB) reduces aromatic and aliphatic aldehydes and ketones to the corresponding alcohols without any CC bond formation and shows good diastereoselectivity in the reduction of the substituted cyclic and polycyclic ketones as well as chiral α‐oxygenated aliphatic ketones. However, in the presence of 10 mol % of ZnCl2, the cyclopentylmagnesium halides follow a normal Grignard addition to the ketones to give tertiary alcohols with complete diastereoselectivity. The reductive as well as the addition protocols were used for the asymmetric synthesis of two medicinally important compounds, (+)‐α‐conhydrine and (S)‐2‐cyclopentyl‐2‐phenylglycolic acid.
Prospects of Metal Complexes Peripherally Substituted with Sugars in Biomedicinal Applications
Authors: Gottschaldt Michael , Schubert Ulrich S.
Published: January 2009

Sugar is good for you! The latest developments in the field of sugar substitution of metal complexes and its influence on the action of these complexes in biological systems are discussed (see figure). In particular, the progress in applications as selective tracers and therapeutics in connection to the underlying chemical structure is highlighted.

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Metal complexes possess unique tunable properties, such as radioactivity, cytotoxicity or photophysical features, enabling them to act as diagnostic tracers or therapeutic agents. In applying them in biological systems, it is often necessary to enhance their solubility and biocompatibility. To achieve such goals, like the targeting of binding domains, transport systems and enzyme activities, the attachment of carbohydrate moieties appears to be suitable. Sugar‐substitution in the periphery of metal complexes has therefore become a strongly growing field of research. Outlined herein is a selection of recent examples.
Highly Efficient Visible‐Light Plasmonic Photocatalyst Ag@AgBr
Authors: Wang Peng , Huang Baibiao , Zhang Xiaoyang , Qin Xiaoyan , Jin Hao , Dai Ying , Wang Zeyan , Wei Jiyong , Zhan Jie , Wang Shaoying , Wang Junpeng , Whangbo Myung‐Hwan
Published: January 2009

Visible improvements: Owing to the plasmon resonance of silver nanoparticles deposited on the surface of AgBr, the newly‐prepared plasmonic photocatalyst Ag§AgBr has a strong absorption in the visible region (see picture) and shows high efficiency in the photodegradation of organic pollutants under visible light.

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Triclosan Derivatives: Towards Potent Inhibitors of Drug‐Sensitive and Drug‐Resistant Mycobacterium tuberculosis
Authors: Freundlich Joel S. , Wang Feng , Vilchèze Catherine , Gulten Gulcin , Langley Robert , Schiehser Guy A. , Jacobus David P. , Jacobs William R. , Sacchettini James C.
Published: January 2009

Overcoming resistance: Isoniazid (INH) is a frontline antitubercular drug that inhibits the enoyl acyl carrier protein reductase InhA. Novel inhibitors of InhA that are not cross‐resistant to INH represent a significant goal in antitubercular chemotherapy. The design, synthesis, and biological activity of a series of triclosan‐based inhibitors is reported, including their promising efficacy against INH‐resistant strains of M. tuberculosis.

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Triclosan has been previously shown to inhibit InhA, an essential enoyl acyl carrier protein reductase involved in mycolic acid biosynthesis, the inhibition of which leads to the lysis of Mycobacterium tuberculosis. Using a structure‐based drug design approach, a series of 5‐substituted triclosan derivatives was developed. Two groups of derivatives with alkyl and aryl substituents, respectively, were identified with dramatically enhanced potency against purified InhA. The most efficacious inhibitor displayed an IC50 value of 21 nM, which was 50‐fold more potent than triclosan. X‐ray crystal structures of InhA in complex with four triclosan derivatives revealed the structural basis for the inhibitory activity. Six selected triclosan derivatives were tested against isoniazid‐sensitive and resistant strains of M. tuberculosis. Among those, the best inhibitor had an MIC value of 4.7 μg mL−1 (13 μM), which represents a tenfold improvement over the bacteriocidal activity of triclosan. A subset of these triclosan analogues was more potent than isoniazid against two isoniazid‐resistant M. tuberculosis strains, demonstrating the significant potential for structure‐based design in the development of next generation antitubercular drugs.
Influence of the baseline 18F‐fluoro‐2‐deoxy‐D‐glucose positron emission tomography results on survival and pathologic response in patients with gastroesophageal cancer undergoing chemoradiation
Authors: Javeri Heta , Xiao Lianchun , Rohren Eric , Komaki Ritsuko , Hofstetter Wayne , Lee Jeffrey H. , Maru Dipen , Bhutani Manoop S. , Swisher Stephen G. , Wang Xuemei , Ajani Jaffer A.
Published: January 2009

BACKGROUND:

In patients with esophageal cancer who receive chemoradiation, tools to predict/prognosticate outcome before administering therapy are lacking. The authors evaluated initial standardized unit value (iSUV) of 18F‐fluoro‐2‐deoxy‐D‐glucose positron emission tomography and its association with overall survival and the degree of pathologic response after surgery.

METHODS:

The authors analyzed 161 patients with esophageal adenocarcinoma who had chemoradiation followed by surgery. The log‐rank test, univariate Cox proportional hazards model, Kaplan‐Meier survival plot, and Fisher exact test were used to analyze dichotomized iSUV and its association with overall survival and pathologic response.

RESULTS:

The median age of 161 patients was 61 years (range, 26‐80 years) and the majority of patients had lower esophageal or gastroesophageal junction involvement. All patients received fluoropyrimidine and, most commonly, a taxane or platinum compound with concomitant radiation. The median radiation dose was 45 grays (Gy) (range, 45 Gy‐50.4 Gy). The median iSUV for all patients was 10.1 (range, 0‐58). Using the Fisher exact test, iSUV was not found to be associated with the location of the primary cancer. iSUV higher than the median (10.1) was associated with a better pathologic response (P= .06). Patients with primary cancer with iSUV >10.1 had a lower risk for death (hazards ratio of 0.56) compared with those with iSUV ≤10.1. Higher iSUV was nonsignificantly associated with improved survival (P= .07).

CONCLUSIONS:

Data from the current study suggest that lower iSUV is associated with poor survival and lower probability of response to chemoradiation. iSUV needs to be further evaluated because it may be used to complement other imaging or biomarker assessments to individualize therapy. Cancer 2009. © 2009 American Cancer Society.
Phase II trial of neoadjuvant docetaxel and gefitinib followed by radical prostatectomy in patients with high‐risk, locally advanced prostate cancer
Authors: Vuky Jacqueline , Porter Christopher , Isacson Christina , Vaughan Matthew , Kozlowski Paul , Picozzi Vincent , Corman John
Published: January 2009

BACKGROUND:

Prostate cancer trials investigating neoadjuvant hormonal therapy, followed by surgery, have demonstrated that elimination of all tumor cells from the primary site is rare. The authors report a phase 2 trial assessing the efficacy and toxicity of docetaxel and gefitinib in patients with high‐risk localized prostate cancer as neoadjuvant therapy before radical prostatectomy (RP).

METHODS:

Thirty‐one patients with high‐risk prostate cancer were treated with docetaxel and gefitinib for 2 months before RP. All patients met the criteria of clinical stage T2b‐3 or serum prostate‐specific antigen (PSA) level >20 ng/mL, or Gleason score of 8 to 10. The primary endpoint was pathologic complete response. Secondary objectives included clinical response. When available, endorectal coil magnetic resonance imaging (eMRI) was performed as part of clinical response evaluation. Immunohistochemical staining of epidermal growth factor receptor and HER‐2/neu was performed on prechemotherapy and postchemotherapy prostate tissue.

RESULTS:

The median age of the patients was 60 years, the median pretreatment PSA level was 7.43 ng/mL, and the median Gleason score was 8. Clinical staging prior to treatment consisted of: T1 in 4 patients, T2 in 17 patients, and T3 in 10 patients. One patient with enlarged pelvic adenopathy and T4 disease did not undergo RP. Thirty patients received all scheduled therapies including RP. Grade 3 toxicities included asymptomatic liver function test elevation in 4 (13%) patients, diarrhea in 1 (3%) patient, and fatigue in 1 (3%) patient. One patient experienced grade 4 toxicity with elevated alanine aminotransferase. RP specimen pathology demonstrated residual carcinoma in all cases. Twenty‐nine (94%) patients achieved a clinical partial response, including 35% of patients who demonstrated radiographic improvement on eMRI.

CONCLUSIONS:

No pathologic complete response was noted in 31 patients treated with docetaxel and gefitinib. This combination was well tolerated, and did not result in increased surgical morbidity. Cancer 2009. © 2009 American Cancer Society.
Influence of Ions on Aqueous Acid–Base Reactions
Authors: Cox M. Jocelyn , Siwick Bradley J. , Bakker Huib J.
Published: January 2009

We study the effects of bromide salts on the rate and mechanism of the aqueous proton/deuteron‐transfer reaction between the photoacid 8‐hydroxy‐1,3,6‐pyrenetrisulfonic acid (HPTS) and the base acetate. The proton/deuteron release is triggered by exciting HPTS with 400 nm femtosecond laser pulses. Probing the electronic and vibrational resonances of the photoacid, the conjugate photobase, the hydrated proton/deuteron and the accepting base with femtosecond visible and mid‐infrared pulses monitors the proton transfer. Two reaction channels are identified: 1) direct long‐range proton transfer over hydrogen‐bonded water bridges that connect the acid and base and 2) acid dissociation to produce fully solvated protons followed by proton scavenging from solution by acetate. We observe that the addition of salt affects the long‐range reaction pathway, and reduces both the rate at which protons are released to solution by HPTS and the rate at which solvated protons are scavenged from solution by acetate. We study the dependence of these effects on the nature and concentration of the dissolved salt.
Effect of Confinement on Proton‐Transfer Reactions in Water Nanopools
Authors: Tielrooij Klaas Jan , Cox M. Jocelyn , Bakker Huib J.
Published: January 2009

Proton transfer from the photoacid 8‐hydroxy‐1,3,6‐pyrenetrisulfonic acid (HPTS) to water is studied in reverse micelles with ionic (AOT=sodium dioctyl sulfosuccinate) and non‐ionic (BRIJ‐30=polyoxyethylene(4)lauryl ether) surfactants. The dynamics are studied by probing the transient electronic absorption and transient vibrational absorption, both with sub‐picosecond resolution. The reverse micelle sizes range from approximately 1.6 to 5.5 nm in diameter. For both surfactants it is found that the rate of proton transfer decreases with decreasing reverse micelle size, regardless of surfactant. In addition, for AOT reverse micelles, a fraction of the photoacid molecules exhibit non‐radiative decay, preventing proton transfer.
Climate Protection by an Alternative Use of Methane—The Carbon Moratorium
Authors: Kreysa Gerhard
Published: January 2009

Despite a rising output, in the last few decades the known reserves of fossil energy resources have steadily increased. Additionally, there are in all likelihood tremendous reserves of methane hydrate. In view of the climate change, new means must be explored for its use as an energy source. Starting with an assessment of various options for dealing with the carbon cycle and thermodynamic considerations of methane chemistry, a new approach for the use of methane as energy source is developed in this Concept. After thermal methane cracking, only the energy content of the hydrogen is used and the carbon is stored safely and retrievably in disused coal beds. Arguments for the viability of a carbon moratorium of this kind are discussed.
TLR2 and TLR4 signaling shapes specific antibody responses to Salmonella typhi antigens
Authors: Cervantes‐Barragán Luisa , Gil‐Cruz Cristina , Pastelin‐Palacios Rodolfo , Lang Karl S. , Isibasi Armando , Ludewig Burkhard , López‐Macías Constantino
Published: January 2009

TLR directly induce innate immune responses by sensing a variety of microbial components and are critical for the fine‐tuning of subsequent adaptive immune responses. However, their impact and mechanism of action on antibody responses against bacterial antigens are not yet fully understood. Salmonella enterica serovar Typhi (S. typhi) porins have been characterized as inducers of long‐lasting specific antibody responses in mice. In this report, we show that immunization of TLR4‐deficient (TLR4−/−), myeloid differentiating gene 88‐deficient and Toll/IL‐R domain‐containing adaptor‐inducing IFN‐β‐deficient mice with S. typhi porins led to significantly reduced B‐cell responses. TLR2−/− mice, as well, showed reduced IgG titers with a more pronounced impairment in the production of IgG3 anti‐porins antibodies. Adoptive transfer of TLR2−/−‐ or TLR4−/−‐B cells into B‐cell‐deficient mice revealed a direct effect of TLR4 on B cells for the primary IgM response, whereas stimulation of B cells via TLR2 was important for IgG production. Furthermore, S. typhi porins were found to efficiently elicit maturation of CD11c+ conventional DC. Taken together, S. typhi porins represent not only a suitable B‐cell antigen for vaccination, but exhibit potent TLR‐dependent stimulatory functions on B cells and DC, which help to further enhance and shape the antibody response.
Fibroblasts from different sites may promote or inhibit recruitment of flowing lymphocytes by endothelial cells
Authors: McGettrick Helen M. , Smith Emily , Filer Andrew , Kissane Stephen , Salmon Michael , Buckley Christopher D. , Rainger G. Ed , Nash Gerard B.
Published: January 2009

We examined the hypothesis that stromal fibroblasts modulate the ability of endothelial cells (EC) to recruit lymphocytes in a site‐specific manner. PBL were perfused over HUVEC that had been cultured with fibroblasts isolated from the inflamed synovium or the skin of patients with rheumatoid arthritis or osteoarthritis, or from normal synovium, with or without exposure to the inflammatory cytokines TNF‐α+IFN‐γ. Fibroblasts from inflamed synovium, but no others, caused unstimulated HUVEC to bind flowing lymphocytes. This adhesion was supported by α4β1‐VCAM‐1 interaction and stabilised by activation of PBL through CXCR4–CXCL12. Antibody neutralisation of IL‐6 during co‐culture effectively abolished the ability of EC to bind lymphocytes. Cytokine‐stimulated EC supported high levels of lymphocyte adhesion, through the presentation of VCAM‐1, E‐selectin and chemokine(s) acting through CXCR3. Interestingly, co‐culture with dermal fibroblasts caused a marked reduction in cytokine‐induced adhesion, while synovial fibroblasts had variable effects depending on their source. In the dermal co‐cultures, neutralisation of IL‐6 or TGF‐β caused partial recovery of cytokine‐induced lymphocyte adhesion; this was complete when both were neutralised. Exogenous IL‐6 was also found to inhibit response to TNF‐α+IFN‐γ. Normal stromal fibroblasts appear to regulate the cytokine‐sensitivity of vascular endothelium, while fibroblasts associated with chronic inflammation bypass this and develop a directly inflammatory phenotype. Actions of IL‐6 might be pro‐inflammatory or anti‐inflammatory, depending on the local milieu.
Anti‐retroviral effects of type I IFN subtypes in vivo
Authors: Gerlach Nicole , Gibbert Kathrin , Alter Christina , Nair Savita , Zelinskyy Gennadiy , James Cassandra M. , Dittmer Ulf
Published: January 2009

Type I IFN play a very important role in immunity against viral infections. Murine type I IFN belongs to a multigene family including 14 IFN‐α subtypes but the biological functions of IFN‐α subtypes in retroviral infections are unknown. We have used the Friend retrovirus model to determine the anti‐viral effects of IFN‐α subtypes in vitro and in vivo. IFN‐α subtypes α1, α4, α6 or α9 suppressed Friend virus (FV) replication in vitro, but differed greatly in their anti‐viral efficacy in vivo. Treatment of FV‐infected mice with the IFN‐α subtypes α1, α4 or α9, but not α6 led to a significant reduction in viral loads. Decreased splenic viral load after IFN‐α1 treatment correlated with an expansion of activated FV‐specific CD8+ T cells and NK cells into the spleen, whereas in IFN‐α4‐ and ‐α9‐treated mice it exclusively correlated with the activation of NK cells. The results demonstrate the distinct anti‐retroviral effects of different IFN‐α subtypes, which may be relevant for new therapeutic approaches.
The role of MAPK in governing lymphocyte adhesion to and migration across the microvasculature in inflammatory bowel disease
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: January 2009

Lymphocyte recruitment is a key pathogenic event in inflammatory bowel disease (IBD). Adhesion of T cells to human intestinal microvascular endothelial cells (HIMEC) is mediated by ICAM‐1, VCAM‐1 and fractalkine (FKN), but the signaling molecules that orchestrate this process have yet to be identified. Because MAPK play an important role in the response of many cell types to pro‐inflammatory stimuli, we assessed the functional role of p38 MAPK, p42/44 MAPK and JNK in the regulation of lymphocyte adhesion to and chemotaxis across the microvasculature in IBD. We found that the MAPK were phosphorylated in the bowel microvasculature and human intestinal fibroblasts of patients with IBD but not of healthy individuals. Stimulation of HIMEC with TNF‐α triggered phosphorylation of the MAPK, and up‐regulation of VCAM‐1, FKN and ICAM‐1. Blockade of p38 decreased the expression of all MAPK by 50% (p<0.01), whereas inhibition of p42/44 decreased the expression of ICAM‐1 and FKN by 50% (p<0.01). Treatment of human intestinal fibroblasts with TNF‐α elicited production of IL‐8 and MCP‐1, which was reduced (p<0.05) by blockade of p38 and p42/44. Finally, blockade of p38 and p42/44 reduced lymphocyte adhesion to (p<0.05) and transmigration across (p<0.05) HIMEC monolayers. These findings suggest a critical role for MAPK in governing lymphocyte influx into the gut in IBD patients, and their blockade may offer a molecular target for blockade of leukocyte recruitment to the intestine.
Tyrosine phosphorylation of scavenger receptor cysteine‐rich WC1 is required for the WC1‐mediated potentiation of TCR‐induced T‐cell proliferation
Authors: Wang Fei , Herzig Carolyn , Ozer Dar , Baldwin Cynthia L. , Telfer Janice C.
Published: January 2009

Workshop cluster 1 (WC1) molecules are transmembrane glycoproteins uniquely expressed by γδ T cells. They belong to the scavenger receptor cysteine‐rich superfamily and are encoded by a multi‐gene family, which is divided on the basis of antibody reactivity, into three groups, WC1.1, WC1.2, and WC1.3. The potential role of WC1 as a co‐stimulatory molecule for the γδ TCR is suggested by the presence of several tyrosine‐based motifs in their intracellular domains. In this study, we found that WC1 was constitutively phosphorylated in ex vivo bovine γδ T cells and associated with src family tyrosine kinases. Crosslinking of WC1 molecules resulted in an increase in WC1 phosphorylation and co‐crosslinking of WC1 and γδ TCR together prolonged WC1 phosphorylation. We identified the second tyrosine residue as the primary phosphorylation target in WC1.1 and WC1.2 intracellular sequences in both in vitro and in vivo assays. The cytoplasmic tails of WC1.1 and WC1.2 were phosphorylated on serine and PKC activity was required for PMA‐induced endocytosis of WC1.1 or WC1.2. We found that phosphorylation of the second tyrosine in the WC1 cytoplasmic domain was required for the WC1‐mediated potentiation of TCR‐induced T‐cell proliferation, suggesting that WC1 acts as a co‐stimulatory molecule for γδ TCR.
PPP1R9B (Neurabin 2): Involvement and dynamics in the NK immunological synapse
Authors: Meng Xiaobo , Kanwar Namita , Du Qiujiang , Goping Ing S. , Bleackley R. Chris , Wilkins John A.
Published: January 2009

The NK immunological synapse (NKIS) is a dynamic structure dependent on the assembly of membrane, cytoskeletal and signaling components. These serve to focus and generate stimuli for adhesion and orientation of the cytoskeleton for targeted cytolytic granule release. Previous studies have demonstrated the importance of the cytoskeleton in these processes. We previously identified PPP1R9B (neurabin 2, spinophilin) as a cytoskeletal component of the NK‐like cell line YTS. We demonstrate that (i) PPP1R9B gradually accumulates at the NKIS in a maturation stage‐dependent manner; (ii) it mimics the early kinetics of actin recruitment to the NKIS but it precedes actin departure from the site; (iii) it is recruited by CD18 stimulation but not by CD28 ligation; (iv) it is required for the maintenance of the cortical F‐actin organization in the YTS cells and knocking down PPP1R9B reduces the frequency of YTS–target cell conjugation, possibly due to the collapsed F‐actin cytoskeleton in these cells. These results indicate that PPP1R9B is required for synapse formation in the NK cells and suggest that it may be involved in the maintenance of cellular architecture by regulation of actin assembly, possibly acting to stabilize the NKIS until granule release is eminent.
CD25+ Treg specifically suppress auto‐Ab generation against pancreatic tissue autoantigens
Authors: Ludwig‐Portugall Isis , Hamilton‐Williams Emma E. , Gotot Janine , Kurts Christian
Published: January 2009

To study B‐cell tolerance against non‐lymphoid tissue autoantigens, we generated transgenic rat insulin promoter (RIP)‐OVA/hen egg lysozyme (HEL) mice expressing the model antigens, OVA and HEL, in pancreatic islets. Their vaccination with OVA or HEL induced far less auto‐Ab titers compared with non‐transgenic controls. Depletion of CD25+ cells during immunization completely restored auto‐Ab production, but did not affect antibodies against a foreign control antigen. Depletion at later time‐points was not effective. OVA‐specific CD25+ FoxP3+ Treg were more frequent in the autoantigen‐draining pancreatic LN than in other secondary lymphatics of RIP‐OVA/HEL mice. Consistently, B cells were suppressed in that LN and also in the spleen, which is known to concentrate circulating antigen, such as the antigens used for vaccination. Suppression involved preventing expansion of autoreactive B cells in response to autoantigen, reducing antibody production per B‐cell and isotype changes. These findings demonstrate that CD25+ Treg suppress auto‐Ab production against non‐lymphoid tissue antigens in an antigen‐specific manner.
In vivo application of mAb directed against the γδ TCR does not deplete but generates “invisible” γδ T cells
Authors: Koenecke Christian , Chennupati Vijaykumar , Schmitz Susanne , Malissen Bernard , Förster Reinhold , Prinz Immo
Published: January 2009

mAb targeting the γδ TCR have been used for γδ T‐cell depletion with varying success. Although the depletion‐capacity of the anti‐γδ TCR mAb clone GL3 has been disputed repeatedly, many groups continue to use γδ T‐cell depletion protocols involving the mAb clone UC7‐13D5 and find significant biological effects. We show here that treatment with both GL3 and UC7‐13D5 antibodies does not deplete γδ T cells in vivo, but rather leads to TCR internalization and thereby generates “invisible” γδ T cells. We addressed this issue using anti‐γδ TCR mAb injections into WT mice as well as into reporter TCR delta locus‐histone 2B enhanced GFP knock‐in mice, in which γδ T cells can be detected based on an intrinsic green fluorescence. Importantly, the use of TCR delta locus‐histone 2B enhanced GFP mice provided here for the first time direct evidence that the “depleted” γδ T cells were actually still present. Our results show further that GL3 and UC7‐13D5 mAb are in part cross‐competing for the same epitope. Assessed by activation markers, we observed in vitro and in vivo activation of γδ T cells through mAb. We conclude that γδ T‐cell depletion experiments must be evaluated with caution and discuss the implications for future studies on the physiological functions of γδ T cells.
Two major groups of rat NKR‐P1 receptors can be distinguished based on chromosomal localization, phylogenetic analysis and Clr ligand binding
Authors: Kveberg Lise , Dai Ke‐Zheng , Westgaard Ingunn H. , Daws Michael R. , Fossum Sigbjørn , Naper Christian , Vaage John T.
Published: January 2009

A major subset of non‐alloreactive NK cells in PVG strain rats is generally low in Ly49 receptors, but expresses the rat NKR‐P1BPVG receptor (previously termed NKR‐P1C). The NKR‐P1B+ NK subset is inhibited by a non‐polymorphic target cell ligand, which we have shown here to be a C‐type lectin‐related molecule (Clr). Clr11 ligates two divergent NKR‐P1B alleles as judged by an NFAT‐driven reporter assay, and inhibits NK‐cell cytotoxicity of NKR‐P1B+ NK cells. Clr11 also interacts with the prototypic NKR‐P1A receptor and exerts a stimulatory influence on NK lysis. NKR‐P1A and B are encoded by adjacent genes in the proximal part of the NK gene complex and show close sequence homology in their extracellular region. They diverge from another pair, NKR‐P1F and ‐G, which is encoded by a second, distal Nkrp1 gene cluster. NKR‐P1F and ‐G bind an overlapping panel of Clr ligands, but not Clr11. Rat Clr molecules appear to be constitutively expressed by hematopoietic cells; expression in tumor cell lines is more variable. The data show the existence of two phylogenetic groups of NKR‐P1 molecules, which demonstrate conservation of ligand‐binding properties independent of signaling function.
Modelling pathways of CD8+ T‐cell differentiation
Authors: Yates Andrew
Published: January 2009

In an immune response to infection, naïve T lymphocytes proliferate and give rise to a heterogeneous population of effector and memory cells. How is this diversity generated, and how can it be manipulated? Answering these questions requires an understanding of the lineage relationships between different effector and memory‐cell subsets, but these relationships remain to be identified definitively. In this issue of the European Journal of Immunology, a study moves us closer to this goal by combining a mathematical model and data from influenza infections in mice to support the hypothesis that CD8+ T‐cell differentiation is strongly coupled to cell division.
Cover Picture: Eur. J. Immunol. 1/09
Authors: Sheng Kuo‐Ching , van Spriel Annemiek B. , Gartlan Kate H. , Sofi Mariam , Apostolopoulos Vasso , Ashman Leonie , Wright Mark D.
Published: January 2009

The cover image is a stylised depiction of tetraspanin‐deficient DC supplied by Sheng et al., the authors of Tetraspanins CD37 and CD151 differentially regulate Ag presentation and T‐cell co‐stimulation by DC (pp. 50‐55). Bone‐marrow‐derived DC were stimulated with LPS and allowed to adhere to glass coverslips. MHC class II was detected by mAb (green/red/orange stainings) and the nuclei stained with TOPRO‐3 (blue). Cells were visualised under confocal microscopy and a collage of images generated using Photoshop CS2.
Regiospecific distribution of fatty acids in triacylglycerols and phospholipids from broad beans (Vicia faba)
Authors: Yoshida Hiromi , Tomiyama Yuka , Yoshida Naoko , Mizushina Yoshiyuki
Published: January 2009

Regiospecific distributions of fatty acids of triacylglycerols (TAG) and phospholipids (PL) separated from broad beans (Vicia faba) of four cultivars (Minpo, Sanuki, Nintoku and Sanren) were investigated. The major lipid components were PL (47.5–50.5 wt‐%) and TAG (47.7–50.1 wt‐%), while steryl esters, hydrocarbons, free fatty acids, diacylglycerols and monoacylglycerols were present in minor proportions (1.6–2.4 wt‐%). The PL components isolated from the four cultivars were phosphatidylcholine (56.4–58.4 wt‐%), phosphatidylethanolamine (20.3–21.7 wt‐%) and phosphatidylinositol (16.6–18.6 wt‐%). Phosphatidylinositol was unique in that it had the highest saturated fatty acid content among these PL. The principal characteristics of the fatty acid distribution in the TAG and PL were evident in the beans: Unsaturated fatty acids were predominantly concentrated in the sn‐2 position while saturated fatty acids primarily occupied the sn‐1 or sn‐3 position in these lipids. The lipid components and fatty acid distributions were almost the same in the four cultivars and were not influenced by genetic variability and planting location. These results could be useful information to both consumers and producers for the manufacture of traditional broad bean foods in Japan.
Enantiospecific Synthesis of a Protected Equivalent of APTO, the β‐Amino Acid Fragment of Microsclerodermins C and D, by Aziridino‐γ‐lactone Methodology
Authors: Tarrade‐Matha Aurélie , Valle Marcelo Siqueira , Tercinier Pierre , Dauban Philippe , Dodd Robert H.
Published: January 2009

The efficient synthesis of a protected form of (2S,3R,4S,5S,7E)‐3‐amino‐8‐phenyl‐2,4,5‐trihydroxyoct‐7‐enoic acid (APTO), the α‐hydroxy β‐amino acid component of microsclerodermins C and D, 23‐membered cyclic peptides isolated from lithistid sponges, is described. The strategy is based on the preparation of the aziridino‐γ‐lactone 46 from L‐gulose by a procedure previously developed in our laboratory for simpler substrates. Regioselective opening of the aziridine at C‐2 by acetate anion, an intrinsic reactivity pattern of aziridino‐γ‐lactones, followed by a Heck reaction to install the terminal phenyl group, provides lactone 48. This, a lactonized form of APTO, can be considered an activated building block for the synthesis of microsclerodermins C and D or their analogues, as demonstrated by its subsequent reaction with a benzylamine to give the carboxamide 51. This represents the first example of the use of an aziridino‐γ‐lactone for the stereoselective synthesis of an α‐substituted β‐amino acid derivative. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Dizinc Phosphohydrolase Model Built on a m‐Terphenyl Scaffold and Its Use in Indicator Displacement Assays for Pyrophosphate Under Physiological Conditions (Eur. J. Org. Chem. 3/2009)
Authors: Coggins Michael K. , Parker Austa M. , Mangalum Anshuman , Galdamez Gabriela A. , Smith Rhett C.
Published: January 2009

The cover picture shows a dizinc phosphohydrolase model built on a m‐terphenyl scaffold that binds pyrophosphate with concomitant displacement of complexometric indicators; this leads to dramatic color changes that can be detected visually and quantified spectroscopically. Details are discussed in the article by R. C. Smith et al. on p. 343 ff.
Dielectrophoretic capture of mammalian cells using transparent indium tin oxide electrodes in microfluidic systems
Authors: Sankaran Bharat , Racic Milena , Tona Alessandro , Rao Mulpuri V. , Gaitan Michael , Forry Samuel P.
Published: January 2009

Transparent indium tin oxide microelectrodes were fabricated and used to immobilize suspended NIH 3T3 fibroblast cells by positive dielectrophoresis. The indium tin oxide electrodes facilitated microscopic observation of immobilized cells compared with opaque metallized electrodes. Dielectrophoresis was used to capture arrays of individual cells and form small cell clusters within a microfluidic network. The extent of cellular immobilization (no‐cell, single‐cell, or multiple‐cell capture) was correlated with the applied voltage and inversely with the flow velocity. Specific conditions yielding predominantly single‐cell capture were identified. The viability of immobilized cells was confirmed using fluorescence microscopy.
Fabrication of PMMA CE microchips by infrared‐assisted polymerization
Authors: Chen Yun , Duan Haotian , Zhang Luyan , Chen Gang
Published: January 2009

In this report, a method based on the infrared‐assisted polymerization of methyl methacrylate has been developed for the rapid fabrication of PMMA CE microchips. Methyl methacrylate containing AIBN was allowed to prepolymerize in a water bath to form a fast‐curing molding solution that was subsequently sandwiched between a silicon template and a piece of 1 mm‐thick PMMA plate. The images of microchannels on the silicon template were precisely replicated into the synthesized PMMA substrates during the infrared‐assisted polymerization of the molding solution. The polymerization could be completed within 50 min at 50°C. The obtained channel plate was subsequently bonded to a piece of PMMA cover sheet to form a microchip with the aid of heat and pressure. The new fabrication approach obviates the need for special equipment and significantly simplifies the process of fabricating PMMA microchips. The attractive performance of the obtained PMMA microchips has been demonstrated in connection with contactless conductivity detection for the separation and detection of ionic species.
Dielectrophoretic characterization of erythrocytes: Positive ABO blood types
Authors: Srivastava Soumya K. , Daggolu Prashant R. , Burgess Shane C. , Minerick Adrienne R.
Published: January 2009

Dielectrophoretic manipulation of erythrocytes/red blood cells is investigated as a tool to identify blood type for medical diagnostic applications. Positive blood types of the ABO typing system (A+, B+, AB+ and O+) were tested and cell responses quantified. The dielectrophoretic response of each blood type was observed in a platinum electrode microdevice, delivering a field of 0.025Vpp/μm at 1 MHz. Responses were recorded via video microscopy for 120 s and erythrocyte positions were tabulated at 20–30 s intervals. Both vertical and horizontal motions of erythrocytes were quantified via image object recognition, object tracking in MATLAB, binning into appropriate electric field contoured regions (wedges) and statistical analysis. Cells of O+ type showed relatively attenuated response to the dielectrophoretic field and were distinguished with greater than 95% confidence from all the other three blood types. AB+ cell responses differed from A+ and B+ blood types likely because AB+ erythrocytes express both the A and B glycoforms on their membrane. This research suggests that dielectrophoresis of untreated erythrocytes beyond simple dilution depends on blood type and could be used in portable blood typing devices.
Development of an acrylate monolith in a cyclo‐olefin copolymer microfluidic device for chip electrochromatography separation
Authors: Faure Karine , Albert Monique , Dugas Vincent , Crétier Gérard , Ferrigno Rosaria , Morin Pierre , Rocca Jean‐Louis
Published: January 2009

An acrylate monolith has been synthesized into a cyclic olefin copolymer microdevice for reversed‐phase electrochromatography purposes. Microchannels, designed by hot embossing, were filled up with an acrylate monolith to serve as a hydrophobic stationary phase. A lauryl acrylate monolith was formulated to suit the hydrophobic material, by implementing 100% organic porogenic solvent. This new composition was tested in capillary prior to its transfer into the microfluidic device. Surface functionalization of the cyclic olefin copolymer surface was applied using UV‐grafting technique to improve the covalent attachment of this monolith to the plastic walls of the microfluidic chip. The on‐chip performances of this monolith were evaluated in detail for the reversed‐phase electrochromatographic separation of polycyclic aromatic hydrocarbons, with plate heights reaching down to 10 μm when working at optimal velocity.
Dual‐color microchip electrophoresis with single‐photon avalanche diodes: Application to mutation detection
Authors: Stenirri Stefania , Cretich Marina , Rech Ivan , Restelli Alessandro , Ghioni Massimo , Cova Sergio , Ferrari Maurizio , Cremonesi Laura , Chiari Marcella
Published: January 2009

A novel microchip electrophoresis instrument based on single‐photon avalanche diodes was used for the molecular characterization of mutations in disease genes. The identification of the main mutation causing cystic fibrosis, named ΔF508, by the Amplification Refractory Mutation System was used to validate the technology. In our implemented protocol the wild‐type and mutant allele‐specific primers are labeled with Cy5 and Cy5.5, respectively. The protocol enables the amplification of the DNA sample in a single PCR. The genotype was deduced from the fluorescence of the amplicons run in the CE microchip. Validation on 15 DNA samples from either homozygous wild‐type or heterozygous and homozygous mutated control subjects proved the complete reliability of the system, thus confirming its high diagnostic potential.