bluuebunny/crossref_metadata_2025 huggingface dataset:
Direct recognition of LPS by human but not murine CD8+ T cells via TLR4 complex
Authors: Komai‐Koma Mousa , Gilchrist Derek S. , Xu Damo
Published: April 2009

LPS comprises a major PAMP and is a key target of the immune system during bacterial infection. While LPS can be recognised by innate immune cells via the TLR4 complex, it is unknown whether T lymphocytes, especially CD8+ T cells are also capable of doing so. We report here that naïve human CD8+ T cells, after activation by TCR stimulation, express surface TLR4 and CD14. These activated CD8+ T cells can then secrete high concentrations of IFN‐γ, granzyme and perforin in response to LPS. These effects can be specifically inhibited using siRNA for TLR4. Furthermore, LPS can synergise with IL‐12 to polarise the CD8+ T cells into cytotoxic T‐cell 1 (Tc1) that produce IFN‐γ but not IL‐4, with or without TCR activation. Moreover, CD8+CD45RO+ memory T cells constitutively expressed TLR4 and markedly enhanced IFN‐γ production when stimulated with LPS. In contrast, activated murine CD8+ T cells lack TLR4 and CD14 expression and fail to respond to LPS for proliferation and cytokine production. Thus, human but not murine CD8+ T cells are able to directly recognise bacterial LPS via LPS receptor complex and TLR4 provides a novel signal for the activation of effector and memory human CD8+ T cells.
Regulatory T cells enter the pancreas during suppression of type 1 diabetes and inhibit effector T cells and macrophages in a TGF‐β‐dependent manner
Authors: Tonkin Daniel R. , Haskins Kathryn
Published: April 2009

Treg can suppress autoimmune diseases such as type 1 diabetes, but their in vivo activity during suppression remains poorly characterized. In type 1 diabetes, Treg activity has been demonstrated in the pancreatic lymph node, but little has been studied in the pancreas, the site of autoimmune islet destruction. In this study we induced islet‐specific Treg from the BDC‐6.9 TCR transgenic mouse by activation of T cells in the presence of TGF‐β. These Treg can suppress spontaneous diabetes as well as transfer of diabetes into NOD.scid mice by diabetic NOD spleen cells or activated BDC‐2.5 TCR transgenic Th1 effector T cells. In the latter transfer model, we observed infiltration of the pancreas by both effector T cells and Treg, suggesting that Treg are active in the inflammatory site and are not just restricted to the draining lymph node. Within the pancreas, we demonstrate that Treg transfer causes a reduction in the number of effector Th1 T cells and macrophages, and also inhibits effector T‐cell cytokine and chemokine production. Although we found no role for TGF‐β in vitro, transfection of effector T cells with a dominant‐negative TGF‐β receptor demonstrated that in vivo suppression of diabetes by TGF‐β‐induced Treg is TGF‐β‐dependent.
Granzyme A expression reveals distinct cytolytic CTL subsets following influenza A virus infection
Authors: Moffat Jessica M. , Gebhardt Thomas , Doherty Peter C. , Turner Stephen J. , Mintern Justine D.
Published: April 2009

CTL mediate anti‐viral immunity via targeted exocytosis of cytolytic granules containing perforin and members of the granzyme (grz) serine protease family. Here, we provide the first analysis of grzA protein expression by murine anti‐viral CTL. During the progression of influenza A virus infection, CTL expressed two divergent cytolytic phenotypes: grzA−B+ and grzA+B+. CTL lacked grzA expression during the initial rounds of antigen‐driven division. High levels of grzA were expressed by influenza‐specific CTL early post infection (day 6), particularly in tissues associated with the infected respiratory tract (bronchoalveolar lavage, lung). Following resolution of influenza infection, a small population of memory CTL expressed grzA. Interestingly, individual influenza A virus‐derived epitope‐specific CTL expressed different levels of grzA. The grzA expression hierarchy was determined to be KbPB1703=DbF262=KbNS2114>DbNP366=DbPA224 and inversely correlated with CTL magnitude. Therefore following influenza infection, a CTL cytolytic hierarchy was established relating to the different profiles of antigen expression and relative immunodominance. Analysis of CTL grzA expression during influenza virus immunity has enabled a more detailed insight into the cytolytic mechanisms of virus elimination.
Requirement of phospholipase C‐γ2 (PLCγ2) for Dectin‐1‐induced antigen presentation and induction of TH1/TH17 polarization
Authors: Tassi Ilaria , Cella Marina , Castro Iris , Gilfillan Susan , Khan Wasif N. , Colonna Marco
Published: April 2009

DC recognize microbial components through an array of receptors known as PRR. PRR initiate intracellular signals, which engender DC with the capacity to stimulate T‐cell responses. Dectin‐1 is a PRR that recognizes β‐glucan, a major constituent of many fungi's outer cell wall. Here we show that Dectin‐1 activates DC through phospholipase (PLC)γ2 signaling. PLCγ2‐deficient DC were unable to expand antigen‐specific T cells and induce TH1 and TH17 differentiation in response to β‐glucan. Mechanistically, PLCγ2‐deficiency impaired the capacity of DC to secrete polarizing cytokines following exposure to β‐glucan. Dectin‐1 required PLCγ2 to activate MAPK, AP‐1 and NF‐κB, which induce cytokine gene expression. Moreover, PLCγ2 controlled Dectin‐1‐mediated NFAT activation and induction of NFAT‐dependent genes such as IL‐2, cyclooxigenase‐2 and Egr transcription factors. We conclude that PLCγ2 is a crucial signaling mediator that modifies DC gene expression program to activate DC responses to β‐glucan‐containing pathogens.
Structural, 103Rh NMR and DFT Studies of a Bis(phosphane)RhIII–Porphyrin Derivative
Authors: Munro Orde Q. , Camp Greville L. , Carlton Laurence
Published: April 2009

The synthesis and characterisation of a novel bis(phosphane)rhodium(III)–porphyrin, [Rh(TPP)(PEtPh2)2]SbF6 (compound 1; TPP = dianion of 5,10,15,20‐tetraphenylporphyrin) is described. The X‐ray structure of the bis(dichloromethane) solvate of the complex has a moderately ruffled porphyrin core conformation, which is primarily determined by the relative orientations of the axial phosphane ligands and their steric interaction with the porphyrin phenyl rings. The mean Rh–N and Rh–P bond lengths for 1 are 2.036(5) and 2.401(3) Å, respectively. The mean absolute perpendicular displacements of the porphyrin α‐, β‐ and meso‐carbon atoms from the 24‐atom porphyrin mean plane measure 0.15(3), 0.11(8) and 0.27(2) Å, respectively. The 103Rh NMR chemical shifts of 1, determined by means of indirect detection through polarisation transfer from 31P, were δ = 2480, 2558 and 2590 ppm at 213, 300 and 333 K, respectively. The 31P chemical shifts measured δ = 10.68, 10.79 and 10.84 ppm at the same temperatures. Ruffled and planar porphyrin conformations are possible for 1 and were modelled by using DFT simulations at the PBE1PBE/3‐21G** level of theory with the cation [Rh(TPP)(PEtPh2)2]+. Accurate structural parameters (calculated bond lengths and out‐of‐plane porphyrin core atom displacements within 2 % and 0.02 Å of the experimental values, respectively) and moderately accurate 103Rh isotropic shielding tensors (δRhcalcd. within 13 % of δRhexp. at 0 K using the GIAO method) were calculated with this hybrid functional and relatively small all‐electron basis set. The DFT simulations indicate unusually high fractional electron populations for the formally antibonding 4d and 4d orbitals of both the ruffled and planar conformers of [Rh(TPP)(PEtPh2)2]+, consistent with the relatively low energies of these metal‐character orbitals that are evidently well‐mixed with ligand orbitals.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
A Quantum Chemical Study of the Structure, Bonding Characteristics and Nonlinear Optical Properties of Aryloxido and Salicylaldehydo Derivatives of [XW5O18]3– (X = Zr or Ti)
Authors: Zhuang Jia , Yan Likai , Liu Chunguang , Su Zhongmin
Published: April 2009

The bonding characteristics, first hyperpolarizabilities, and origin of the nonlinear optical (NLO) properties of aryloxido and salicylaldehydo derivatives of [XW5O18]3– (X = Zr or Ti) have been investigated using density functional theory (DFT). The flexible bonding behavior of the linkage oxygen (OL) atom attracted our attention initially, and NBO analysis revealed that there aret two different kinds of π‐interactions involving the OL atom in these systems. In two aryloxido derivatives (systems 1 and 2), OL–metal π‐interactions are largely OL–M p‐d in character, whereas in the salicylaldehydo derivatives (system 3) we observed another kind of π‐interaction, namely OL–C p‐p π‐bonding. The differences in molecular composition in our studied systems are very slight. However, the β0 values differ significantly. Thus, system 3 has the largest β0 value(559.27 × 10–30 esu), which is 170 times larger than that of system 1. This variation can be traced to the different electronic transitions and charge‐transfer characteristics. The heteropolyanion cluster and organic ligand are both electron‐rich groups. A small change in molecular composition or architecture can therefore significantly modify the configuration and overlapping of molecular orbitals, thus causing a “butterfly effect” upon the electronic transitions and charge‐transfer characteristics.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Analysis of the Interaction between Adenine Nucleobase and Metal‐Malonato Complexes
Authors: Pérez‐Yáñez Sonia , Castillo Oscar , Cepeda Javier , García‐Terán Juan P. , Luque Antonio , Román Pascual
Published: April 2009

The synthesis, crystal structure and variable‐temperature magnetic measurements of compounds [M2(μ‐Hade)2(μ‐mal)2(H2O)2]·2H2O [M = Ni (1), Co (2)], [Co2(μ‐Hade)2(μ‐mal)2(H2O)2] (3), {(H2ade)2[Cu(μ‐mal)2]·2H2O}n (4) and (H2ade)2[Cu(mmal)2(H2O)] (5; H2ade = adeninium, Hade = adenine, mal = malonato, mmal = methylmalonato) are reported. Compounds 1–3 contain neutral paddle‐wheel [M2(μ‐Hade)2(μ‐mal)2(H2O)2] [M = Ni (1), Co (2 and 3)] units where the 7H‐tautomeric form of the nucleobase and the malonate dianion act as μ‐κN3:κN9 and μ‐κ2O1,O2:κO1 bridging ligands, respectively. The supramolecular crystal structures of 1–3 are essentially maintained by hydrogen‐bonding interactions involving the nucleobases, the carboxylate groups and crystallisation water molecules (in compounds 1 and 2). Compounds 4 and 5 show a hybrid inorganic‐organic lamellar structure containing layers of anionic metal‐malonato complexes and supramolecular aggregates of the 1H,9H‐adeninium cation. Their overall three‐dimensional architectures are controlled, in addition to electrostatic forces, by supramolecular recognition processes between the inorganic and organic frameworks. Compound 4 contains one‐dimensional anionic copper‐malonato chains in which the copper atoms are doubly bridged by μ‐κ2O1,O2:κO2′ malonato ligands and the cationic nucleobases form dimeric entities sustained by Hoogsteen‐Hoogsteen hydrogen‐bonding interactions. Compound 5 is built up of anionic [Cu(mmal)2(H2O)]2– monomeric entities and planar, hydrogen‐bonded, one‐dimensional, ribbon‐like aggregates of protonated adenine. Variable‐temperature magnetic susceptibility measurements of compounds 1–4 show the preponderance of ferromagnetic interactions between the paramagnetic centres. DFT calculations have been performed to evaluate the magnetic behaviour of these compounds and to analyze the interaction between two adeninium cations in compound 4. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Water‐Soluble Ultra Small Paramagnetic or Superparamagnetic Metal Oxide Nanoparticles for Molecular MR Imaging
Authors: Park Ja Young , Choi Eun Sook , Baek Myung Ju , Lee Gang Ho , Woo Seungtae , Chang Yongmin
Published: April 2009

A simple and general one‐pot synthesis for water‐soluble ligand‐coated ultra small paramagnetic or superparamagnetic metal oxide nanoparticles with average particle diameters (dav.) that range from 1–3 nm has been developed and used in molecular magnetic resonance (MR) imaging. The iron oxide, manganese oxide, and gadolinium oxide nanoparticles are coated with various hydrophilic and biocompatible ligands. We found that the ligand‐coated ultra small gadolinium oxide nanoparticles are the superior candidates for use as T1 MRI contrast agents. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Synthesis of 9‐Substituted‐1,8‐Dioxooctahydroxanthenes by an Efficient Iodine‐Catalyzed Cyclization
Authors: Luna Liliana E. , Cravero Raquel M. , Faccio Ricardo , Pardo Helena , Mombrú Álvaro W. , Seoane Gustavo
Published: April 2009

New 1,8‐dioxooctahydroxanthenes with substituents in the 2‐, 3‐, and 9‐positions were obtained by cyclization with iodine from tandem Michael/Michael adducts. The X‐ray molecular structure of the methyl 2‐(1,8‐dioxo‐2,3,4,5,6,7,8,9‐octahydro‐1H‐xanthen‐9‐yl)acetate (3a) was solved and shows the parallel laminae packing of these molecules. Furthermore, we reported the structure of intermediate 4 isolated from this reaction. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Synthesis and Characterization of Highly Fluorinated Gemini Pyridinium Surfactants
Authors: Quagliotto Pierluigi , Barolo Claudia , Barbero Nadia , Barni Ermanno , Compari Carlotta , Fisicaro Emilia , Viscardi Guido
Published: April 2009

A series of fluorinated gemini pyridinium amphiphiles have been prepared, purified and fully characterized. The synthesis was performed using alkyl trifluoromethanesulfonates as the quaternizing agents, provided very good yields and overcame problems arising with other less powerful alkylating agents. The use of different characterization techniques, such as conductivity and surface tension measurements, shed light on the aggregation process. The title products showed interesting, unusual properties, which could be interpreted in view of a peculiar aggregating behaviour. This family of compounds is very interesting for their possible transfection activity and application in gene therapy. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Intramolecular Nonbonded Interactions Between Divalent Selenium Centers with Donor and Acceptor Substituents
Authors: Lari Alberth , Bleiholder Christian , Rominger Frank , Gleiter Rolf
Published: April 2009

To investigate the intramolecular van der Waals interactions between two divalent selenium centers in the solid state and in solution, we have prepared methyl 2‐(methylselenyl)benzyl selenide (1), ethynyl 2‐(methylselenyl)benzyl selenide (2), and 2‐(methylselenyl)benzyl selenocyanate (3). By means of NMR spectroscopic studies we have determined the 77Se NMR chemical shifts of the signals of the Se centers of 1–3 and their long‐range 4JSe,Se coupling constants. These results, and the X‐ray structural studies of single crystals of 3 and 11, a quasi‐dimer of 2, point to an Se···Se van der Waals interaction and short Se···H distances in 1–3. These measurements were supported by quantum chemical calculations on 1–3 at the MP2/6‐311+g(d)//B98/6‐311+g(d) level of theory, which showed a preference for the endoX and endoH conformations of 1–3. This finding was confirmed by calculations of the 77Se NMR chemical shifts of 1–3 by GIAO‐B98 and GIAO‐PBE calculations.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Molecularly Imprinted Polymerized Methylene Green as a Platform for Electrochemical Sensing of Aptamer–Thrombin Interactions
Authors: Evtugyn Gennady , Porfireva Anna , Ivanov Alexey , Konovalova Olga , Hianik Tibor
Published: April 2009

The biosensors based on DNA aptamers immobilized by electrostatic adsorption onto electropolymerized Methylene Green (MG)) imprinted with DNA have been developed and examined for thrombin detection in the range from 1 nM to 1 μM using electrochemical impedance spectroscopy (EIS) and potentiometry. The participation of DNA in MG electropolymerization and imprints formation was proved by measurements of EIS and redox signals of neutral and charged indicators. Changes in the morphology of the layers were examined using atomic force microscopy (AFM). The addition of DNA at the electropolymerization stage followed by acidic treatment of the coating significantly improved the efficiency of electrostatic adsorption of the DNA aptamer and provided sensitive detection of thrombin with limit of detection 0.5 nM.
Impedimetric or Ion‐Sensitive Field‐Effect Transistor (ISFET) Aptasensors Based on the Self‐Assembly of Au Nanoparticle‐Functionalized Supramolecular Aptamer Nanostructures
Authors: Sharon Etery , Freeman Ronit , Tel‐Vered Ran , Willner Itamar
Published: April 2009

Two electrical methods (Faradaic impedance spectroscopy and ion‐sensitive field‐effect transistor (ISFET)) are applied to sense aptamer‐substrate complexes. The methods utilize anticocaine aptamer fragments that self‐assemble, in the presence of cocaine, to a supramolecular aptamer fragments/cocaine complex on the electrode surface or ISFET gate. One of the aptamer fragments is assembled on a Au electrode or the ISFET gate. The second thiolated aptamer fragment is used to modify Au NPs that are used as amplifying labels for the two detection schemes. The impedimetric and ISFET methods enabled the analysis of cocaine with detection limits of 1×10−5 M and 1×10−6 M, respectively.
Reduction of hexamminecobalt (III) catalyzed by coconut activated carbon
Authors: Long Xiang‐li , Cheng Hua , Yuan Wei‐kang
Published: April 2009

The wet ammonia desulphurization process can be retrofitted to remove NO and SO2 simultaneously by adding soluble cobalt (II) salt into the aqueous ammonia solution. The hexamminecobalt (II), Co(NH3), is the active constituent in the removal of nitric oxide with the hexamminecobalt ammonia solution. To maintain the capability of removing NO with the hexamminecobalt solution, activated carbon is used to catalyze the reduction of hexamminecobalt (III) to hexamminecobalt (II). In this study, the study on the investigation into the intrinsic kinetics of the hexamminecobalt (III) conversion has been performed. The reduction of hexamminecobalt (III) catalyzed by coconut activated carbon has been studied in a batch stirred cell without the external or internal mass transfer resistances. The experimental results show that the reaction rate increases with the activated carbon mass and the concentration of hexamminecobalt (III). pH affects the reaction greatly. A best Co(NH3)63+ conversion is obtained at pH of 2.74. A high temperature is favorable to such reaction. The reaction is first order with respect to Co(NH3)63+. The intrinsic activation energy of 56.73 ± 1.82 kJ mol−1 has been obtained. A kinetic model for such catalytic reaction can be expressed as follow:

© 2009 American Institute of Chemical Engineers Environ Prog, 2010
Rethinking climate change impacts on subsurface temperatures in a sub‐Antarctic mire affected by synoptic scale processes
Authors: Nel Werner , van der Merwe Barend J. , Meiklejohn K. Ian
Published: April 2009

This paper presents the first high resolution temperature data from a small Agrostis magellanica mire on subantarctic Marion Island as part of an ongoing island‐wide monitoring project on subsurface ground temperature variability. Variations in ground temperatures were found to be directly linked to the passage of synoptic scale weather systems that influence thermal characteristics and heat fluxes especially in the upper 30 cm of the mire. Preliminary data published here suggest that shallow temperatures will be most affected by changes in synoptic climate that Marion Island is currently experiencing with an increase in average temperatures and a reduction in temperature variability with depth. This study proposes that to effectively detect the ecosystem responses to climate change in a maritime sub‐Antarctic environment the temporal scale of measurement needs to be at least on a diurnal scale to be effective. Copyright © 2009 John Wiley & Sons, Ltd.
Developing a unified FVE‐ALE approach to solve unsteady fluid flow with moving boundaries
Authors: Naderi A. , Darbandi M. , Taeibi‐Rahni M.
Published: April 2009

In this study, an arbitrary Lagrangian–Eulerian (ALE) approach is incorporated with a mixed finite‐volume–element (FVE) method to establish a novel moving boundary method for simulating unsteady incompressible flow on non‐stationary meshes. The method collects the advantages of both finite‐volume and finite‐element (FE) methods as well as the ALE approach in a unified algorithm. In this regard, the convection terms are treated at the cell faces using a physical‐influence upwinding scheme, while the diffusion terms are treated using bilinear FE shape functions. On the other hand, the performance of ALE approach is improved by using the Laplace method to improve the hybrid grids, involving triangular and quadrilateral elements, either partially or entirely. The use of hybrid FE grids facilitates this achievement. To show the robustness of the unified algorithm, we examine both the first‐ and the second‐order temporal stencils. The accuracy and performance of the extended method are evaluated via simulating the unsteady flow fields around a fixed cylinder, a transversely oscillating cylinder, and in a channel with an indented wall. The numerical results presented demonstrate significant accuracy benefits for the new hybrid method on coarse meshes and where large time steps are taken. Of importance, the current method yields the second‐order temporal accuracy when the second‐order stencil is used to discretize the unsteady terms. Copyright © 2009 John Wiley & Sons, Ltd.
1‐D numerical modelling of shallow flows with variable horizontal density
Authors: Leighton Feifei Zhang , Borthwick Alistair G. L. , Taylor Paul H.
Published: April 2009

A1‐D numerical model is presented for vertically homogeneous shallow flows with variable horizontal density. The governing equations represent depth‐averaged mass and momentum conservation of a liquid–species mixture, and mass conservation of the species in the horizontal direction. Here, the term ‘species’ refers to material transported with the liquid flow. For example, when the species is taken to be suspended sediment, the model provides an idealized simulation of hyper‐concentrated sediment‐laden flows. The volumetric species concentration acts as an active scalar, allowing the species dynamics to modify the flow structure. A Godunov‐type finite volume scheme is implemented to solve the conservation laws written in a deviatoric, hyperbolic form. The model is verified for variable‐density flows, where analytical steady‐state solutions are derived. The agreement between the numerical predictions and benchmark test solutions illustrates the ability of the model to capture rapidly varying flow features over uniform and non‐uniform bed topography. A parameter study examines the effects of varying the initial density and depth in different regions. Copyright © 2009 John Wiley & Sons, Ltd.
Integrated genomic and transcriptional analysis of the in vitro evolution of telomerase‐immortalized urothelial cells (TERT‐NHUC)
Authors: Chapman Emma J. , Williams Sarah V. , Platt Fiona M. , Hurst Carolyn D. , Chambers Philip , Roberts Paul , Knowles Margaret A.
Published: April 2009

Much progress has been made in identifying the molecular genetic alterations that occur in bladder cancer. However, in many cases the genes targeted by these alterations are not known. Telomerase immortalized human urothelial cells (TERT‐NHUC) are a useful resource for in vitro studies of genes involved in urothelial transformation. When cultured under standard conditions they remain genetically stable but when cultured under low‐density conditions they exhibit genetic instability and acquire chromosomal alterations. TERT‐NHUC from three donors were cultured at low plating density and examined at four time‐points during a culture period of 600 days. Analyses included population doubling kinetics, array‐based CGH (aCGH), chromosome counts, fluorescence in situ hybridization (FISH), mutation analysis, Affymetrix gene expression analysis, Western blotting for p16, anchorage‐independent growth and tumorigenicity assays. Alterations acquired during continued culture of TERT‐NHUC at low density (TERT‐NHUC‐L) included some observed in urothelial carcinoma (UC) cell lines and primary UC. Examination of gene expression in TERT‐NHUC with distinct acquired genetic aberrations may pinpoint genes targeted by these alterations. Data from an aCGH study of UC cell lines and primary tumors were examined for changes in chromosomal regions that also showed alterations in TERT‐NHUC‐L. Loss of a region on 2q including BOK was identified in UC cell lines and primary tumors. DNER and FRAS1 were identified as potential candidate genes, whose expression is altered independently of the acquisition of any genetic event. © 2009 Wiley‐Liss, Inc.
When the solution is part of the problem: problem solving in elderly suicide attempters
Authors: Gibbs Lawrence M. , Dombrovski Alexandre Y. , Morse Jennifer , Siegle Greg J. , Houck Patricia R. , Szanto Katalin
Published: April 2009

Objectives

Depression, loss, and physical illness are associated with suicide in the elderly. However, the nature of individual vulnerability remains poorly understood. Poor problem solving has been suggested as a risk factor for suicide in younger adults. Unresolved problems may create an accumulation of stressors. Thus, those with perceived deficits in problem‐solving ability may be predisposed to suicidal behavior. To test this hypothesis, we investigated whether elderly suicide attempters perceived their problem solving as deficient.

Methods

Sixty‐four individuals aged 60 and older participated in the study including depressed suicide attempters, depressed non‐attempters, and non‐depressed controls. The social problem solving inventory‐revised: short‐version was used to measure participants' perceived social problem solving, assessing both adaptive problem‐solving dimensions (positive problem orientation and rational problem solving) and dysfunctional dimensions (negative problem orientation, impulsivity/carelessness, and avoidance).

Results

Depressed elderly who had attempted suicide perceived their overall problem solving as deficient, compared to non‐suicidal depressed and non‐depressed elderly. Suicide attempters perceived their problems more negatively and approached them in a more impulsive manner. On rational problem solving and avoidant style sub‐scales, suicide attempters did not differ from non‐suicidal depressed. However, both depressed groups reported lower rational problem solving and higher avoidance compared to non‐depressed controls.

Conclusions

A perception of life problems as threatening and unsolvable and an impulsive approach to problem solving appear to predispose vulnerable elderly to suicide attempts. Copyright © 2009 John Wiley & Sons, Ltd.
Reductions in neuronal density in elderly depressed are region specific
Authors: Van Otterloo Eric , O'Dwyer Gillian , Stockmeier Craig A. , Steffens David C. , Krishnan Ranga R. , Rajkowska Grazyna
Published: April 2009

Objective

Frontal regions, including the orbitofrontal cortex (ORB) and dorsolateral prefrontal cortex (dlPFC) have been implicated in the neuropathology of geriatric depression. Prominent reductions in pyramidal neuron density have been recently reported in the ORB of older depressed subjects. However, the cellular pathology of the dlPFC has not yet been examined in these subjects.

Methods

Postmortem tissue from the dlPFC (Brodmann's area 9, BA9) was collected from 10 older (>60 years old) subjects diagnosed with major depression and 10 age‐matched non‐psychiatric controls (CTRL). The majority of the subjects were the same as those used for our previous study on neuronal reductions in the ORB in older depressed. Overall (all six layers combined), and laminar density of pyramidal (presumably glutamatergic), and non‐pyramidal (GABAergic) neurons as well as cortical and laminar width were measured using linear optical disector of Stereoinvestigator software.

Results

Neither the overall nor laminar density of pyramidal or non‐pyramidal neurons was significantly different between groups. The cortical and laminar widths were also not affected.

Conclusions

These results suggest that neuronal prefrontal pathology in elderly depressed is region specific. No significant changes were detected in the density of any type of neurons in the dlPFC of elderly depressed subjects (present study) whereas, prominent reductions in the density of pyramidal glutamatergic neurons were observed previously in the ORB. Copyright © 2009 John Wiley & Sons, Ltd.
Quantitative diffusion tensor imaging in amyotrophic lateral sclerosis: Revisited
Authors: Sage Caroline A. , Van Hecke Wim , Peeters Ronald , Sijbers Jan , Robberecht Wim , Parizel Paul , Marchal Guy , Leemans Alexander , Sunaert Stefan
Published: April 2009

Voxel‐based analyses (VBA) are increasingly being used to detect white matter abnormalities with diffusion tensor imaging (DTI) in different types of pathologies. However, the validity, specificity, and sensitivity of statistical inferences of group differences to a large extent depend on the quality of the spatial normalization of the DTI images. Using high‐dimensional nonrigid coregistration techniques that are able to align both the spatial and orientational diffusion information and incorporate appropriate templates that contain this complete DT information may improve this quality. Alternatively, a hybrid technique such as tract‐based spatial statistics (TBSS) may improve the reliability of the statistical results by generating voxel‐wise statistics without the need for perfect image alignment and spatial smoothing. In this study, we have used (1) a coregistration algorithm that was optimized for coregistration of DTI data and (2) a population‐based DTI atlas to reanalyze our previously published VBA, which compared the fractional anisotropy and mean diffusivity maps of patients with amyotrophic lateral sclerosis (ALS) with those of healthy controls. Additionally, we performed a complementary TBSS analysis to improve our understanding and interpretation of the VBA results. We demonstrate that, as the overall variance of the diffusion properties is lowered after normalizing the DTI data with such recently developed techniques (VBA using our own optimized high‐dimensional nonrigid coregistration and TBSS), more reliable voxel‐wise statistical results can be obtained than had previously been possible, with our VBA and TBSS yielding very similar results. This study provides support for the view of ALS as a multisystem disease, in which the entire frontotemporal lobe is implicated. Hum Brain Mapp, 2009. © 2009 Wiley‐Liss, Inc.
Neural correlates of the females' susceptibility to negative emotions: An insight into gender‐related prevalence of affective disturbances
Authors: Yuan Jiajin , Luo Yuejia , Yan Jin H. , Meng Xianxin , Yu Fengqiong , Li Hong
Published: April 2009

Considerable studies reported that females are more susceptible to affective disturbances such as depression, anxiety disorder, and phobia compared to males. Based on the close relation between emotional sensitivity and liability to affective disturbances (Hofer et al. [2006]: NeuroImage 32, 854–862; Spearing [2001]: Bipolar disorder, 2nd ed. Bethesda (MA): National institute of Mental Health), this study investigated the neural mechanism underlying the females' liability to affective disturbances by hypothesizing that females are more susceptible to negative emotions than males. Event‐related potentials (ERPs) were recorded for highly negative (HN), moderately negative (MN), and neutral images in Experiment 1, and for highly positive, moderately positive, and neutral images in Experiment 2, whereas subjects (15 males and 15 females) performed a standard/deviant distinction task, irrespective of the emotional valence of deviants in both experiments. In addition to the prominent emotional reactions evoked by HN stimuli in both genders, Experiment 1 displayed conspicuous emotional responses of females to MN stimuli across N2 and P3 components, which were absent in males. In contrast, Experiment 2 demonstrated neither significant valence effect, nor significant valence by gender interaction effect at these components. Thus, although both genders are sensitive to HN stimuli, females, instead of males, are particularly susceptible to negative stimuli of lesser salience, and this female specific susceptibility does not exist to the positive stimuli. Therefore, females must be more susceptible to negative emotions in life settings, which may be one important mechanism underlying their higher prevalence of affective disturbances. Hum Brain Mapp, 2009. © 2009 Wiley‐Liss, Inc.
Management of squamous cell carcinoma of the base of tongue with chemoradiation and brachytherapy
Authors: Cano Elmer R. , Lai Stephen Y. , Caylakli Fatma , Johnson Jonas T. , Ferris Robert L. , Carrau Ricardo L. , Snyderman Carl H. , Gooding William E. , Simenthal Alfred A. , Myers Eugene N.
Published: April 2009

Background.

Treatment of base of tongue (BOT) squamous cell carcinoma (SCC) has traditionally been associated with poor prognosis and significant morbidity. We report a program consisting of concurrent chemoradiation followed by brachytherapy for these patients.

Methods.

We reviewed all patients in our institution with previously untreated BOT SCC (1996–2004) who received this treatment program.

Results.

In 88 patients (median age, 60.2 years; 37 T1/T2; 51 T3/T4), cervical lymph node metastases were present in 71 patients (80.7%). Six patients had residual/subsequent cervical metastases requiring 7 neck dissections. Local recurrence occurred in 16 patients (18.2%) and distant metastases occurred in 9 patients (10.2%). Median follow‐up time was 3.1 years (range, 0.5–7.8 years). Three‐year overall survival was 80.9% (95% CI: 69.6% to 88.3%). Locoregional control rate was 79.9% and disease‐specific survival was 69.5% at 3 years.

Conclusions.

Concurrent chemoradiotherapy followed with brachytherapy is a safe and effective method of treatment of SCC of the BOT. © 2009 Wiley Periodicals, Inc. Head Neck, 2009
Image‐guided surgery in an occult neck metastasis
Authors: Mierzwa Kathleen , Mueller Andreas
Published: April 2009

Background.

We report a case of a squamous cell carcinoma of the right tonsillar region with 5 metastatic lymph nodes and a retropharyngeal metastasis, the latter detected in the preoperative MRI scan.

Methods and Results.

The treatment consisted of excision of the tumor in the oral cavity and the bilateral neck dissection. Despite careful exploration, a retropharyngeal metastasis was not identifiable during this procedure. This failure encouraged us to use navigation‐guided surgery in a second step. The difficulty in using navigation in soft tissue of the neck is the fixation of the neck. Therefore, a thermoplastic head mask, normally indicated in radiation therapy, was used for both the preoperative CT and navigation‐guided surgery. The retropharyngeal metastasis was successfully excised with this method.

Conclusion.

This is the first reported attempt to use navigation‐guided surgery in the soft tissue of the neck. It reveals new opportunities for navigation in the future. © 2009 Wiley Periodicals, Inc. Head Neck, 2010
Elevated parathyroid hormone levels after parathyroidectomy for primary hyperparathyroidism
Authors: Mizrachi Aviram , Gilat Hanna , Bachar Gideon , Feinmesser Raphael , Shpitzer Thomas
Published: April 2009

Background.

Curative parathyroidectomy is associated with elevated levels of parathyroid hormone (PTH) with eucalcemia. This study sought to determine the frequency, clinical significance, and risk factors of this finding.

Methods.

Seventy‐six consecutive patients surgically treated for primary hyperparathyroidism due to a single parathyroid adenoma in 2006 to 2007 were monitored for 1 month postoperatively; those with elevated PTH levels (>70 pg/mL) were monitored for 18 months.

Results.

Nineteen patients (25%) had high postoperative PTH levels with normal calcium levels. Compared with the remaining patients, this group had a significantly higher average preoperative PTH level (224.89 vs 156.86 pg/mL) and a lesser intraoperative decrease in PTH.

Conclusions.

About 25% of eucalcemic patients may have elevated PTH levels after parathyroidectomy. A high preoperative PTH level (>225 pg/mL) may predict a persistently high postoperative level. Evaluation of blood and urine calcium, bone density, and cardiac function should be considered in affected patients. Head Neck, 2009
Initial clinical experience with helical tomotherapy for head and neck cancer
Authors: Chen Allen M. , Jennelle Richard L. S. , Sreeraman Radhika , Yang Claus C. , Liu Tianxiao , Vijayakumar Srinivasan , Purdy James A.
Published: April 2009

Background.

To report a single‐institutional experience with the use of helical tomotherapy (HT)‐based intensity‐modulated radiotherapy (IMRT) for head and neck cancer.

Methods.

Seventy‐seven consecutive patients were treated with HT for squamous cell carcinoma of the head and neck to a median dose of 66 Gy (range, 60 to 72 Gy). Megavoltage CT scans were obtained as part of an image‐guided registration protocol for patient alignment before each treatment. Concurrent chemotherapy was administered to 48 patients (62%).

Results.

The 2‐year estimates of overall survival, local‐regional control, and disease‐free survival were 82%, 77%, and 71%, respectively. Spatial evaluation of local‐regional failures revealed that 16 of the 18 patients who progressed in the primary site or neck failed in the high‐dose planning target volume (PTV).

Conclusions.

HT appears to achieve clinical outcomes comparable to contemporary series reporting on IMRT for head and neck cancer. © 2009 Wiley Periodicals, Inc. Head Neck, 2009
Move it or lose it—Is stimulation of the vestibular system necessary for normal spatial memory?
Authors: Smith Paul F. , Darlington Cynthia. L. , Zheng Yiwen
Published: April 2009

Studies in both experimental animals and human patients have demonstrated that peripheral vestibular lesions, especially bilateral lesions, are associated with spatial memory impairment that is long‐lasting and may even be permanent. Electrophysiological evidence from animals indicates that bilateral vestibular loss causes place cells and theta activity to become dysfunctional; the most recent human evidence suggests that the hippocampus may cause atrophy in patients with bilateral vestibular lesions. Taken together, these studies suggest that self‐motion information provided by the vestibular system is important for the development of spatial memory by areas of the brain such as the hippocampus, and when it is lost, spatial memory is impaired. This naturally suggests the converse possibility that activation of the vestibular system may enhance memory. Surprisingly, there is some human evidence that this may be the case. This review considers the relationship between the vestibular system and memory and suggests that the evolutionary age of this primitive sensory system as well as how it detects self‐motion (i.e., detection of acceleration vs. velocity) may be the reasons for its unique contribution to spatial memory. © 2009 Wiley‐Liss, Inc.
Establishing a relationship between activity reduction in human perirhinal cortex and priming
Authors: Voss Joel L. , Hauner Katherina K.Y. , Paller Ken A.
Published: April 2009

Perirhinal neurons exhibit reduced firing rates with stimulus repetition, a phenomenon termed “repetition suppression.” However, relationships between perirhinal repetition suppression and behavioral expressions of memory remain unclear. We used anatomically constrained functional magnetic resonance imaging (fMRI) to assess relationships between perirhinal activity and priming, a type of implicit memory. Priming was expressed as speeded animacy judgments for old versus new words. Concurrently, old words elicited less neural activity in bilateral perirhinal cortex. The magnitude of the left perirhinal activity reduction selectively predicted the magnitude of behavioral priming in an across‐subjects hierarchical linear regression analysis. These findings have implications for considering how perirhinal cortex may contribute to different neurocognitive functions, possibly including both implicit memory and familiarity‐based recognition. This study documents the first evidence linking behavioral measures of priming to information processing in perirhinal cortex. © 2009 Wiley‐Liss, Inc.
The hippocampus contributes to memory expression during transitive inference in mice
Authors: DeVito Loren M. , Kanter Benjamin R. , Eichenbaum Howard
Published: April 2009

There is substantial evidence that the hippocampus plays a role in transitive inference, the capacity to link overlapping memories and subsequently make novel judgments between elements of those memories that are only indirectly related. However, it is unclear whether the hippocampus is involved primarily during the original acquisition of the overlapping memories, or additionally during the flexible expression of those memories during transitive judgments. Here, we demonstrated that selective hippocampal damage produced after acquisition of the overlapping memories resulted in a severe impairment in subsequent transitive inference judgments, indicating that the hippocampus does play an important role beyond the initial learning phase. Furthermore, this study extends to mice a role for the hippocampus in transitive inference, as previously observed in other species. © 2009 Wiley‐Liss, Inc.
Low‐frequency‐induced synaptic potentiation: A paradigm shift in the field of memory‐related plasticity mechanisms?
Authors: Habib Diala , Dringenberg Hans C.
Published: April 2009

Long‐term potentiation (LTP) and long‐term depression (LTD) are two forms of synaptic plasticity thought to play functional roles in learning and memory processes. It is generally assumed that the direction of synaptic modifications (i.e., up‐ or down‐regulation of synaptic strength) depends on the specific pattern of afferent inputs, with high frequency activity or stimulation effectively inducing LTP, while low‐frequency patterns often elicit LTD. This dogma (“high frequency‐LTP, low frequency‐LTD”) has recently been challenged by evidence demonstrating low frequency stimulation (LFS)‐induced synaptic potentiation in the rodent hippocampus and amygdala. Extensive work in the past decades has focused on deciphering the mechanisms by which high frequency stimulation of afferent fiber systems results in LTP. With this review, we will compare and contrast the well‐known synaptic and cellular mechanisms underlying classical, high‐frequency‐induced LTP to those mediating the more recently discovered phenomena of LFS‐induced synaptic enhancement. In addition, we argue that LFS protocols provide a means to more accurately mimic some endogenous, oscillatory activity patterns present in hippocampal and extra‐hippocampal (especially neocortical) circuits during periods of memory consolidation. Consequently, LFS‐induced synaptic potentiation offers a novel and important avenue to investigate cellular and systems‐level mechanisms mediating the encoding, consolidation, and transfer of information throughout multiple forebrain networks implicated in learning and memory processes. © 2009 Wiley‐Liss, Inc.
Oxidative stress status and RNA expression in hippocampus of an animal model of Alzheimer's disease after chronic exposure to aluminum
Authors: Garcia Tania , Esparza José L. , Nogués M. Rosa , Romeu Marta , Domingo José L. , Gómez Mercedes
Published: April 2009

It is well established that aluminum (Al) is a neurotoxic agent that induces the production of free radicals in brain. Accumulation of free radicals may cause degenerative events of aging such as Alzheimer's disease. On the other hand, melatonin (Mel) is a known antioxidant, which can directly act as free radical scavenger, or indirectly by inducing the expression of some genes linked to the antioxidant defense. In this study, AβPP female transgenic (Tg2576) (Tg) and wild‐type mice (5 months of age) were fed with Al lactate supplemented in the diet (1 mg Al/g diet). Simultaneously, animals received oral Mel (10 mg/kg) dissolved in tap water until the end of the study at 11 months of age. Four treatment groups were included for both Tg and wild‐type mice: control, Al only, Mel only, and Al+Mel. At the end of the period of treatment, hippocampus was removed and processed to examine the following oxidative stress markers: reduced glutathione (GSH), oxidized glutathione (GSSG), superoxide dismutase (SOD), glutathione reductase (GR), glutathione peroxidase (GPx), catalase (CAT), and thiobarbituric acid reactive substances (TBARS). Moreover, the gene expression of Cu‐ZnSOD, GR, and CAT was evaluated by real‐time RT‐PCR. Aluminum concentration in hippocampus was also determined. The biochemical changes observed in this tissue suggest that Al acts as a pro‐oxidant agent. Melatonin exerts an antioxidant action by increasing the mRNA levels of the antioxidant enzymes SOD, CAT, and GR evaluated in presence of Al and Mel, with independence of the animal model. © 2009 Wiley‐Liss, Inc.
Parametric surface modeling and registration for comparison of manual and automated segmentation of the hippocampus
Authors: Shen Li , Firpi Hiram A. , Saykin Andrew J. , West John D.
Published: April 2009

Accurate and efficient segmentation of the hippocampus from brain images is a challenging issue. Although experienced anatomic tracers can be reliable, manual segmentation is a time consuming process and may not be feasible for large‐scale neuroimaging studies. In this article, we compare an automated method, FreeSurfer (V4), with a published manual protocol on the determination of hippocampal boundaries from magnetic resonance imaging scans, using data from an existing mild cognitive impairment/Alzheimer's disease cohort. To perform the comparison, we develop an enhanced spherical harmonic processing framework to model and register these hippocampal traces. The framework treats the two hippocampi as a single geometric configuration and extracts the positional, orientation, and shape variables in a multiobject setting. We apply this framework to register manual tracing and FreeSurfer results together and the two methods show stronger agreement on position and orientation than shape measures. Work is in progress to examine a refined FreeSurfer segmentation strategy and an improved agreement on shape features is expected. © 2009 Wiley‐Liss, Inc.