bluuebunny/crossref_metadata_2025 huggingface dataset:
Interaction of KCNE subunits with the KCNQ1 K+ channel pore
Authors: Panaghie Gianina , Tai Kwok‐Keung , Abbott Geoffrey W.
Published: November 2005

KCNQ1 α subunits form functionally distinct potassium channels by coassembling with KCNE ancillary subunits MinK and MiRP2. MinK‐KCNQ1 channels generate the slowly activating, voltage‐dependent cardiac IKs current. MiRP2‐KCNQ1 channels form a constitutively active current in the colon. The structural basis for these contrasting channel properties, and the mechanisms of α subunit modulation by KCNE subunits, are not fully understood. Here, scanning mutagenesis located a tryptophan‐tolerant region at positions 338–340 within the KCNQ1 pore‐lining S6 domain, suggesting an exposed region possibly amenable to interaction with transmembrane ancillary subunits. This hypothesis was tested using concomitant mutagenesis in KCNQ1 and in the membrane‐localized ‘activation triplet’ regions of MinK and MiRP2 to identify pairs of residues that interact to control KCNQ1 activation. Three pairs of mutations exerted dramatic effects, ablating channel function or either removing or restoring control of KCNQ1 activation. The results place KCNE subunits close to the KCNQ1 pore, indicating interaction of MiRP2‐72 with KCNQ1‐338; and MinK‐59,58 with KCNQ1‐339, 340. These data are consistent either with perturbation of the S6 domain by MinK or MiRP2, dissimilar positioning of MinK and MiRP2 within the channel complex, or both. Further, the results suggest specifically that two of the interactions, MiRP2‐72/KCNQ1‐338 and MinK‐58/KCNQ1‐340, are required for the contrasting gating effects of MinK and MiRP2.
A role for 5,6‐epoxyeicosatrienoic acid in calcium entry by de novo conformational coupling in human platelets
Authors: Ben‐Amor Nidhal , Redondo Pedro C. , Bartegi Aghleb , Pariente José A. , Salido Ginés M. , Rosado Juan A.
Published: November 2005

A major pathway for Ca2+ entry in non‐excitable cells is activated following depletion of intracellular Ca2+ stores. A de novo conformational coupling between elements in the plasma membrane (PM) and Ca2+ stores has been proposed as the most likely mechanism to activate this capacitative Ca2+ entry (CCE) in several cell types, including platelets. Here we report that a cytochrome P450 metabolite, 5,6‐EET, might be a component of the de novo conformational coupling in human platelets. In these cells, 5,6‐EET induces divalent cation entry without having any detectable effect on Ca2+ store depletion. 5,6‐EET‐induced Ca2+ entry was sensitive to the CCE blockers 2‐APB, lanthanum, SKF‐96365 and nickel and impaired by incubation with anti‐hTRPC1 antibody. Ca2+ entry stimulated by low concentrations of thapsigargin, which selectively depletes the dense tubular system and induces EET production, was impaired by the cytochrome P450 inhibitor 17‐ODYA, which has no effect on CCE mediated by depletion of the acidic stores using 2,5‐di‐(tert‐butyl)‐1,4‐hydroquinone. We have found that 5,6‐EET‐induced Ca2+ entry requires basal levels of H2O2, which might maintain a redox state favourable for this event. Finally, our results indicate that 5,6‐EET induces the activation of tyrosine kinase proteins and the reorganization of the actin cytoskeleton, which might provide a support for the transport of portions of the Ca2+ store towards the PM to facilitate de novo coupling between IP3R type II and hTRPC1 detected by coimmunoprecipitation. We propose that the involvement of 5,6‐EET in TG‐induced coupling between IP3R type II and hTRPC1 and subsequently CCE is compatible with the de novo conformational coupling in human platelets.
Dependence of Mechanical Behavior of the Murine Tail Disc on Regional Material Properties: A Parametric Finite Element Study
Authors: Hsieh Adam H. , Wagner Diane R. , Cheng Louis Y. , Lotz Jeffrey C.
Published: November 2005

In vivo rodent tail models are becoming more widely used for exploring the role of mechanical loading on the initiation and progression of intervertebral disc degeneration. Historically, finite element models (FEMs) have been useful for predicting disc mechanics in humans. However, differences in geometry and tissue properties may limit the predictive utility of these models for rodent discs. Clearly, models that are specific for rodent tail discs and accurately simulate the disc’s transient mechanical behavior would serve as important tools for clarifying disc mechanics in these animal models. An FEM was developed based on the structure, geometry, and scale of the mouse tail disc. Importantly, two sources of time-dependent mechanical behavior were incorporated: viscoelasticity of the matrix, and fluid permeation. In addition, a novel strain-dependent swelling pressure was implemented through the introduction of a dilatational stress in nuclear elements. The model was then validated against data from quasi-static tension-compression and compressive creep experiments performed previously using mouse tail discs. Finally, sensitivity analyses were performed in which material parameters of each disc subregion were individually varied. During disc compression, matrix consolidation was observed to occur preferentially at the periphery of the nucleus pulposus. Sensitivity analyses revealed that disc mechanics was greatly influenced by changes in nucleus pulposus material properties, but rather insensitive to variations in any of the endplate properties. Moreover, three key features of the model—nuclear swelling pressure, lamellar collagen viscoelasticity, and interstitial fluid permeation—were found to be critical for accurate simulation of disc mechanics. In particular, collagen viscoelasticity dominated the transient behavior of the disc during the initial 2200s of creep loading, while fluid permeation governed disc deformation thereafter. The FEM developed in this study exhibited excellent agreement with transient creep behavior of intact mouse tail motion segments. Notably, the model was able to produce spatial variations in nucleus pulposus matrix consolidation that are consistent with previous observations in nuclear cell morphology made in mouse discs using confocal microscopy. Results of this study emphasize the need for including nucleus swelling pressure, collagen viscoelasticity, and fluid permeation when simulating transient changes in matrix and fluid stress/strain. Sensitivity analyses suggest that further characterization of nucleus pulposus material properties should be pursued, due to its significance in steady-state and transient disc mechanical response.
Viscoelastic Testing Methodologies for Tissue Engineered Blood Vessels
Authors: Berglund Joseph D. , Nerem Robert M. , Sambanis Athanassios
Published: November 2005

In order to function in vivo, tissue engineered blood vessels (TEBVs) must encumber pulsatile blood flow and withstand hemodynamic pressures for long periods of time. To date TEBV mechanical assessment has typically relied on single time point burst and/or uniaxial tensile testing to gauge the strengths of the constructs. This study extends this analysis to include creep and stepwise stress relaxation viscoelastic testing methodologies. TEBV models exhibiting diverse mechanical behaviors as a result of different architectures ranging from reconstituted collagen gels to hybrid constructs reinforced with either untreated or glutaraldhyde-crosslinked collagen supports were evaluated after 8 and 23 days of in vitro culturing. Data were modeled using three and four-parameter linear viscoelastic mathematical representations and compared to porcine carotid arteries. While glutaraldhyde-treated hybrid TEBVs exhibited the largest overall strengths and toughness, uncrosslinked hybrid samples exhibited time-dependent behaviors most similar to native arteries. These findings emphasize the importance of viscoelastic characterization when evaluating the mechanical performance of TEBVs. Limits of testing methods and modeling systems are presented and discussed.
The Origins of Syringomyelia: Numerical Models of Fluid/Structure Interactions in the Spinal Cord
Authors: Bertram C. D. , Brodbelt A. R. , Stoodley M. A.
Published: November 2005

A two-dimensional axi-symmetric numerical model is constructed of the spinal cord, consisting of elastic cord tissue surrounded by aqueous cerebrospinal fluid, in turn surrounded by elastic dura. The geometric and elastic parameters are simplified but of realistic order, compared with existing measurements. A distal reflecting site models scar tissue formed by earlier trauma to the cord, which is commonly associated with syrinx formation. Transients equivalent to both arterial pulsation and percussive coughing are used to excite wave propagation. Propagation is investigated in this model and one with a central canal down the middle of the cord tissue, and in further idealized versions of it, including a model with no cord, one with a rigid cord, one with a rigid dura, and a double-length untapered variant of the rigid-dura model. Analytical predictions for axial and radial wave-speeds in these different situations are compared with, and used to explain, the numerical outcomes. We find that the anatomic circumstances of the spinal cerebrospinal fluid cavity probably do not allow for significant wave steepening phenomena. The results indicate that wave propagation in the real cord is set by the elastic properties of both the cord tissue and the confining dura mater, fat, and bone. The central canal does not influence the wave propagation significantly.
Turbulent Flow Evaluation of the Venous Needle During Hemodialysis
Authors: Unnikrishnan Sunil , Huynh Thanh N. , Brott B. C. , Ito Y. , Cheng C. H. , Shih A. M. , Allon M. , Anayiotos Andreas S.
Published: November 2005

Arteriovenous (AV) grafts and fistulas used for hemodialysis frequently develop intimal hyperplasia (IH) at the venous anastomosis of the graft, leading to flow-limiting stenosis, and ultimately to graft failure due to thrombosis. Although the high AV access blood flow has been implicated in the pathogenesis of graft stenosis, the potential role of needle turbulence during hemodialysis is relatively unexplored. High turbulent stresses from the needle jet that reach the venous anastomosis may contribute to endothelial denudation and vessel wall injury. This may trigger the molecular and cellular cascade involving platelet activation and IH, leading to eventual graft failure. In an in-vitro graft/needle model dye injection flow visualization was used for qualitative study of flow patterns, whereas laser Doppler velocimetry was used to compare the levels of turbulence at the venous anastomosis in the presence and absence of a venous needle jet. Considerably higher turbulence was observed downstream of the venous needle, in comparison to graft flow alone without the needle. While turbulent RMS remained around 0.1m∕s for the graft flow alone, turbulent RMS fluctuations downstream of the needle soared to 0.4–0.7m∕s at 2 cm from the tip of the needle and maintained values higher than 0.1m∕s up to 7–8 cm downstream. Turbulent intensities were 5–6 times greater in the presence of the needle, in comparison with graft flow alone. Since hemodialysis patients are exposed to needle turbulence for four hours three times a week, the role of post-venous needle turbulence may be important in the pathogenesis of AV graft complications. A better understanding of the role of needle turbulence in the mechanisms of AV graft failure may lead to improved design of AV grafts and venous needles associated with reduced turbulence, and to pharmacological interventions that attenuate IH and graft failure resulting from turbulence.
Representation of Action-Specific Reward Values in the Striatum
Authors: Samejima Kazuyuki , Ueda Yasumasa , Doya Kenji , Kimura Minoru
Published: November 2005

The estimation of the reward an action will yield is critical in decision-making. To elucidate the role of the basal ganglia in this process, we recorded striatal neurons of monkeys who chose between left and right handle turns, based on the estimated reward probabilities of the actions. During a delay period before the choices, the activity of more than one-third of striatal projection neurons was selective to the values of one of the two actions. Fewer neurons were tuned to relative values or action choice. These results suggest representation of action values in the striatum, which can guide action selection in the basal ganglia circuit.
Assistance of Microbial Glycolipid Antigen Processing by CD1e
Authors: de la Salle Henri , Mariotti Sabrina , Angenieux Catherine , Gilleron Martine , Garcia-Alles Luis-Fernando , Malm Dag , Berg Thomas , Paoletti Samantha , Maître Blandine , Mourey Lionel , Salamero Jean , Cazenave Jean Pierre , Hanau Daniel , Mori Lucia , Puzo Germain , De Libero Gennaro
Published: November 2005

Complexes between CD1 molecules and self or microbial glycolipids represent important immunogenic ligands for specific subsets of T cells. However, the function of one of the CD1 family members, CD1e, has yet to be determined. Here, we show that the mycobacterial antigens hexamannosylated phosphatidyl-
myo
-inositols (PIM
6
) stimulate CD1b-restricted T cells only after partial digestion of the oligomannose moiety by lysosomal α-mannosidase and that soluble CD1e is required for this processing. Furthermore, recombinant CD1e was able to bind glycolipids and assist in the digestion of PIM
6
. We propose that, through this form of glycolipid editing, CD1e helps expand the repertoire of glycolipidic T cell antigens to optimize antimicrobial immune responses.
SMEDWI-2 Is a PIWI-Like Protein That Regulates Planarian Stem Cells
Authors: Reddien Peter W. , Oviedo Néstor J. , Jennings Joya R. , Jenkin James C. , Alvarado Alejandro Sánchez
Published: November 2005

We have identified two genes,
smedwi-1
and
smedwi-2
, expressed in the dividing adult stem cells (neoblasts) of the planarian
Schmidtea mediterranea
. Both genes encode proteins that belong to the Argonaute/PIWI protein family and that share highest homology with those proteins defined by
Drosophila
PIWI. RNA interference (RNAi) of
smedwi-2
blocks regeneration, even though neoblasts are present, irradiation-sensitive, and capable of proliferating in response to wounding;
smedwi-2(RNAi)
neoblast progeny migrate to sites of cell turnover but, unlike normal cells, fail at replacing aged tissue. We suggest that SMEDWI-2 functions within dividing neoblasts to support the generation of cells that promote regeneration and homeostasis.
The Phanerozoic Record of Global Sea-Level Change
Authors: Miller Kenneth G. , Kominz Michelle A. , Browning James V. , Wright James D. , Mountain Gregory S. , Katz Miriam E. , Sugarman Peter J. , Cramer Benjamin S. , Christie-Blick Nicholas , Pekar Stephen F.
Published: November 2005

We review Phanerozoic sea-level changes [543 million years ago (Ma) to the present] on various time scales and present a new sea-level record for the past 100 million years (My). Long-term sea level peaked at 100 ± 50 meters during the Cretaceous, implying that ocean-crust production rates were much lower than previously inferred. Sea level mirrors oxygen isotope variations, reflecting ice-volume change on the 10
4
- to 10
6
-year scale, but a link between oxygen isotope and sea level on the 10
7
-year scale must be due to temperature changes that we attribute to tectonically controlled carbon dioxide variations. Sea-level change has influenced phytoplankton evolution, ocean chemistry, and the loci of carbonate, organic carbon, and siliciclastic sediment burial. Over the past 100 My, sea-level changes reflect global climate evolution from a time of ephemeral Antarctic ice sheets (100 to 33 Ma), through a time of large ice sheets primarily in Antarctica (33 to 2.5 Ma), to a world with large Antarctic and large, variable Northern Hemisphere ice sheets (2.5 Ma to the present).
Nucleus Accumbens Long-Term Depression and the Expression of Behavioral Sensitization
Authors: Brebner Karen , Wong Tak Pan , Liu Lidong , Liu Yitao , Campsall Paul , Gray Sarah , Phelps Lindsay , Phillips Anthony G. , Wang Yu Tian
Published: November 2005

Drug-dependent neural plasticity related to drug addiction and schizophrenia can be modeled in animals as behavioral sensitization, which is induced by repeated noncontingent or self-administration of many drugs of abuse. Molecular mechanisms that are critical for behavioral sensitization have yet to be specified. Long-term depression (LTD) of α-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid receptor (AMPAR)–mediated synaptic transmission in the brain has been proposed as a cellular substrate for learning and memory. The expression of LTD in the nucleus accumbens (NAc) required clathrin-dependent endocytosis of postsynaptic AMPARs. NAc LTD was blocked by a dynamin-derived peptide that inhibited clathrin-mediated endocytosis or by a GluR2-derived peptide that blocked regulated AMPAR endocytosis. Systemic or intra-NAc infusion of the membrane-permeable GluR2 peptide prevented the expression of amphetamine-induced behavioral sensitization in the rat.
Wingless Signaling at Synapses Is Through Cleavage and Nuclear Import of Receptor DFrizzled2
Authors: Mathew Dennis , Ataman Bulent , Chen Jinyun , Zhang Yali , Cumberledge Susan , Budnik Vivian
Published: November 2005

Wingless secretion provides pivotal signals during development by activating transcription of target genes. At
Drosophila
synapses, Wingless is secreted from presynaptic terminals and is required for synaptic growth and differentiation. Wingless binds the seven-pass transmembrane DFrizzled2 receptor, but the ensuing events at synapses are not known. We show that DFrizzled2 is endocytosed from the postsynaptic membrane and transported to the nucleus. The C terminus of DFrizzled2 is cleaved and translocated into the nucleus; the N-terminal region remains just outside the nucleus. Translocation of DFrizzled2-C into the nucleus, but not its cleavage and transport, depends on Wingless signaling. We conclude that, at synapses, Wingless signal transduction occurs through the nuclear localization of DFrizzled2-C for potential transcriptional regulation of synapse development.
Singing Icebergs
Authors: Müller Christian , Schlindwein Vera , Eckstaller Alfons , Miller Heinrich
Published: November 2005

Sustained harmonic tremor signals were recorded by the seismographs of the German Neumayer Base seismological network in western Dronning Maud Land, Antarctica. These tremor episodes, lasting up to 16 hours, were recorded up to 820 kilometers from the source. Their spectra show narrow peaks with fundamental frequencies ranging from 0.5 to 6 hertz, more than 30 integer harmonic overtones, and frequency gliding, resembling volcanic tremor. Frequency‐wave number analysis suggested a moving source, which was recognized as iceberg B-09A traveling along the coast of eastern Antarctica. The most probable tremor sources are fluid-flow‐induced vibrations inside the iceberg's tunnel/crevasse systems.
The Nature of Aqueous Tunneling Pathways Between Electron-Transfer Proteins
Authors: Lin Jianping , Balabin Ilya A. , Beratan David N.
Published: November 2005

Structured water molecules near redox cofactors were found recently to accelerate electron-transfer (ET) kinetics in several systems. Theoretical study of interprotein electron transfer across an aqueous interface reveals three distinctive electronic coupling mechanisms that we describe here: (i) a protein-mediated regime when the two proteins are in van der Waals contact; (ii) a structured water-mediated regime featuring anomalously weak distance decay at relatively close protein-protein contact distances; and (iii) a bulk water–mediated regime at large distances. Our analysis explains a range of otherwise puzzling biological ET kinetic data and provides a framework for including explicit water-mediated tunneling effects on ET kinetics.
Encoding Electronic Properties by Synthesis of Axial Modulation-Doped Silicon Nanowires
Authors: Yang Chen , Zhong Zhaohui , Lieber Charles M.
Published: November 2005

We describe the successful synthesis of modulation-doped silicon nanowires by achieving pure axial elongation without radial overcoating during the growth process. Scanning gate microscopy shows that the key properties of the modulated structures—including the number, size, and period of the differentially doped regions—are defined in a controllable manner during synthesis, and moreover, that feature sizes to less than 50 nanometers are possible. Electronic devices fabricated with designed modulation-doped nanowire structures demonstrate their potential for lithography-independent address decoders and tunable, coupled quantum dots in which changes in electronic properties are encoded by synthesis rather than created by conventional lithography-based techniques.
Hf-W Chronometry of Lunar Metals and the Age and Early Differentiation of the Moon
Authors: Kleine Thorsten , Palme Herbert , Mezger Klaus , Halliday Alex N.
Published: November 2005

The use of hafnium-tungsten chronometry to date the Moon is hampered by cosmogenic tungsten-182 production mainly by neutron capture of tantalum-181 at the lunar surface. We report tungsten isotope data for lunar metals, which contain no
181
Ta-derived cosmogenic
182
W. The data reveal differences in indigenous
182
W/
184
W of lunar mantle reservoirs, indicating crystallization of the lunar magma ocean 4.527 ± 0.010 billion years ago. This age is consistent with the giant impact hypothesis and defines the completion of the major stage of Earth's accretion.
Super-Compressible Foamlike Carbon Nanotube Films
Authors: Cao Anyuan , Dickrell Pamela L. , Sawyer W. Gregory , Ghasemi-Nejhad Mehrdad N. , Ajayan Pulickel M.
Published: November 2005

We report that freestanding films of vertically aligned carbon nanotubes exhibit super-compressible foamlike behavior. Under compression, the nanotubes collectively form zigzag buckles that can fully unfold to their original length upon load release. Compared with conventional low-density flexible foams, the nanotube films show much higher compressive strength, recovery rate, and sag factor, and the open-cell nature of the nanotube arrays gives excellent breathability. The nanotube films present a class of open-cell foam structures, consisting of well-arranged one-dimensional units (nanotube struts). The lightweight, highly resilient nanotube films may be useful as compliant and energy-absorbing coatings.
Vertebrate-Type Intron-Rich Genes in the Marine Annelid
Platynereis dumerilii
Authors: Raible Florian , Tessmar-Raible Kristin , Osoegawa Kazutoyo , Wincker Patrick , Jubin Claire , Balavoine Guillaume , Ferrier David , Benes Vladimir , de Jong Pieter , Weissenbach Jean , Bork Peer , Arendt Detlev
Published: November 2005

Previous genome comparisons have suggested that one important trend in vertebrate evolution has been a sharp rise in intron abundance. By using genomic data and expressed sequence tags from the marine annelid
Platynereis dumerilii
, we provide direct evidence that about two-thirds of human introns predate the bilaterian radiation but were lost from insect and nematode genomes to a large extent. A comparison of coding exon sequences confirms the ancestral nature of
Platynereis
and human genes. Thus, the urbilaterian ancestor had complex, intron-rich genes that have been retained in
Platynereis
and human.
Cassini Discovers a Kinematic Spiral Ring Around Saturn
Authors: Charnoz S. , Porco C. C. , Déau E. , Brahic A. , Spitale J. N. , Bacques G. , Baillie K.
Published: November 2005

Since the time of the Voyager flybys of Saturn in 1980–1981, Saturn's eccentric F ring has been known to be accompanied on either side by faint strands of material. New Cassini observations show that these strands, initially interpreted as concentric ring segments, are in fact connected and form a single one-arm trailing spiral winding at least three times around Saturn. The spiral rotates around Saturn with the orbital motion of its constituent particles. This structure is likely the result of differential orbital motion stretching an initial cloud of particles scattered from the dense core of the F ring. Different scenarios of formation, implying ringlet-satellite interactions, are explored. A recently discovered moon candidate, S/2004 S6, is on an orbit that crosses the F-ring core at the intersection of the spiral with the ring, which suggests a dynamical connection between S/2004 S6 and the spiral.
Stable Carbon CycleClimate Relationship During the Late Pleistocene
Authors: Siegenthaler Urs , Stocker Thomas F. , Monnin Eric , Lüthi Dieter , Schwander Jakob , Stauffer Bernhard , Raynaud Dominique , Barnola Jean-Marc , Fischer Hubertus , Masson-Delmotte Valérie , Jouzel Jean
Published: November 2005

A record of atmospheric carbon dioxide (CO
2
) concentrations measured on the EPICA (European Project for Ice Coring in Antarctica) Dome Concordia ice core extends the Vostok CO
2
record back to 650,000 years before the present (yr B.P.). Before 430,000 yr B.P., partial pressure of atmospheric CO
2
lies within the range of 260 and 180 parts per million by volume. This range is almost 30% smaller than that of the last four glacial cycles; however, the apparent sensitivity between deuterium and CO
2
remains stable throughout the six glacial cycles, suggesting that the relationship between CO
2
and Antarctic climate remained rather constant over this interval.
Atmospheric Methane and Nitrous Oxide of the Late Pleistocene from Antarctic Ice Cores
Authors: Spahni Renato , Chappellaz Jérôme , Stocker Thomas F. , Loulergue Laetitia , Hausammann Gregor , Kawamura Kenji , Flückiger Jacqueline , Schwander Jakob , Raynaud Dominique , Masson-Delmotte Valérie , Jouzel Jean
Published: November 2005

The European Project for Ice Coring in Antarctica Dome C ice core enables us to extend existing records of atmospheric methane (CH
4
) and nitrous oxide (N
2
O) back to 650,000 years before the present. A combined record of CH
4
measured along the Dome C and the Vostok ice cores demonstrates, within the resolution of our measurements, that preindustrial concentrations over Antarctica have not exceeded 773 ± 15 ppbv (parts per billion by volume) during the past 650,000 years. Before 420,000 years ago, when interglacials were cooler, maximum CH
4
concentrations were only about 600 ppbv, similar to lower Holocene values. In contrast, the N
2
O record shows maximum concentrations of 278 ± 7 ppbv, slightly higher than early Holocene values.
The Kinase LKB1 Mediates Glucose Homeostasis in Liver and Therapeutic Effects of Metformin
Authors: Shaw Reuben J. , Lamia Katja A. , Vasquez Debbie , Koo Seung-Hoi , Bardeesy Nabeel , DePinho Ronald A. , Montminy Marc , Cantley Lewis C.
Published: November 2005

The Peutz-Jegher syndrome tumor-suppressor gene encodes a protein-threonine kinase, LKB1, which phosphorylates and activates AMPK [adenosine monophosphate (AMP)–activated protein kinase]. The deletion of LKB1 in the liver of adult mice resulted in a nearly complete loss of AMPK activity. Loss of LKB1 function resulted in hyperglycemia with increased gluconeogenic and lipogenic gene expression. In LKB1-deficient livers, TORC2, a transcriptional coactivator of CREB (cAMP response element–binding protein), was dephosphorylated and entered the nucleus, driving the expression of peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α), which in turn drives gluconeogenesis. Adenoviral small hairpin RNA (shRNA) for TORC2 reduced PGC-1α expression and normalized blood glucose levels in mice with deleted liver LKB1, indicating that TORC2 is a critical target of LKB1/AMPK signals in the regulation of gluconeogenesis. Finally, we show that metformin, one of the most widely prescribed type 2 diabetes therapeutics, requires LKB1 in the liver to lower blood glucose levels.
The Widespread Impact of Mammalian MicroRNAs on mRNA Repression and Evolution
Authors: Farh Kyle Kai-How , Grimson Andrew , Jan Calvin , Lewis Benjamin P. , Johnston Wendy K. , Lim Lee P. , Burge Christopher B. , Bartel David P.
Published: November 2005

Thousands of mammalian messenger RNAs are under selective pressure to maintain 7-nucleotide sites matching microRNAs (miRNAs). We found that these conserved targets are often highly expressed at developmental stages before miRNA expression and that their levels tend to fall as the miRNA that targets them begins to accumulate. Nonconserved sites, which outnumber the conserved sites 10 to 1, also mediate repression. As a consequence, genes preferentially expressed at the same time and place as a miRNA have evolved to selectively avoid sites matching the miRNA. This phenomenon of selective avoidance extends to thousands of genes and enables spatial and temporal specificities of miRNAs to be revealed by finding tissues and developmental stages in which messages with corresponding sites are expressed at lower levels.
The Outer Limits of Belief
Authors: Vyse Stuart
Published: November 2005

Abducted
. How People Come to Believe They Were Kidnapped by Aliens.
By Susan A. Clancy
. Harvard University Press, Cambridge, MA, 2005. 191 pp. $22.95, £14.95, €21.20. ISBN 0-674-01879-6.

The author's consideration of people who believe they have been abducted by aliens illuminates the ease with which people can remember events that never happened.
Characterisation of adherens and tight junctional molecules in normal animal larynx; determining a suitable model for studying molecular abnormalities in human laryngopharyngeal reflux
Authors: Gill G A , Buda A , Moorghen M , Dettmar P W , Pignatelli M
Published: November 2005

Background:The disruption of intercellular junctions in the larynx is a pathological feature of laryngopharyngeal reflux (LPR). Good experimental models are necessary to gain greater insight into the molecular mechanisms and alterations that result from abnormal exposure of the laryngeal epithelium to acid refluxate.

Aims:To characterise laryngeal tissues from different species to determine the most suitable for use in experimental studies of LPR.

Methods:Human and non-human laryngeal tissues (mouse, rat, guinea pig, porcine, and rabbit) were studied. Histological characterisation was performed by light microscopy. The expression and subcellular localisation of adherens junctional molecules (E-cadherin and β catenin) was evaluated by immunohistochemistry, and tight junction molecules (occludin and zonula occludens 1 (ZO-1)) by western blotting. The ultrastructural features of porcine and human tissue were assessed by electron microscopy.

Results:Porcine tissue revealed both respiratory-type and stratified squamous epithelium, as seen in the human larynx. The expression and subcellular localisation of the E-cadherin–catenin complex was detected in all species except mouse and rat. The pattern of ZO-1 and occludin expression was preserved in all species.

Conclusion:The expression of intercellular junctional complexes in porcine epithelium is similar to that seen in humans. These results confirm the suitability of these species to study molecular mechanisms of LPR in an experimental system.
Pure testicular carcinoid associated with intratubular germ cell neoplasia
Authors: Merino J , Zuluaga A , Gutierrez-Tejero F , del Mar Serrano M , Ciani S , Nogales F F
Published: November 2005

This case report describes for the first time a case of pure testicular carcinoid preaortic lymph node metastases in a 25 year old patient with carcinoid syndrome. The simultaneous occurrence of intratubular germ cell neoplasia in the surrounding testicular tissue was identified by OCT4 and placental-like alkaline phosphatase positivity. This confirmed that the tumour had a germ cell origin in the testis, rather than being a metastasis from an extragenital carcinoid.
Comparison of the novel quantitative ARMS assay and an enriched PCR–ASO assay for K-rasmutations with conventional cytology on endobiliary brush cytology from 312 consecutive extrahepatic biliary stenoses
Authors: van Heek N T , Clayton S J , Sturm P D J , Walker J , Gouma D J , Noorduyn L A , Offerhaus G J A , Fox J C
Published: November 2005

Background:Extrahepatic biliary stenosis (EBS) has malignant and benign causes. Patients with EBS are at risk of having or developing malignancy. Accurate diagnostic tests for early detection and surveillance are needed. The sensitivity of biliary cytology for malignancy is low. K-rasmutation analysis on brush cytology is a valuable adjunct, but specificity is low. A quantitative test for K-rasmutations has been developed: the amplification refractory mutation system (ARMS).

Aim:To assess the test characteristics and additional value of ARMS in diagnosing the cause of EBS.

Methods:Brush samples from endoscopic retrograde cholangiopancreatography were collected from 312 patients with EBS. K-rasmutation analysis was performed using ARMS—allele specific amplification was coupled with real time fluorescent detection of PCR products. Results were compared with conventional cytology and K-rasmutation analysis using allele specific oligonucleotide (ASO) hybridisation, and evaluated in view of the final diagnosis.

Results:The test characteristics of ARMS and ASO largely agreed. Sensitivity for detecting malignancy was 49% and 42%, specificity 93% and 88%, and positive predictive value (PPV) 96% and 91%, respectively. The sensitivity of ARMS and cytology combined was 71%, and PPV was 93%. The specificity of ARMS could be increased to 100% by setting limits for the false positives, but reduced sensitivity from 49% to 43%.

Conclusions:ARMS can be considered supplementary to conventional cytology, and comparable to ASO in diagnosing malignant EBS. A specificity of 100% can be achieved with ARMS, which should be considered in the surveillance of patients at risk for pancreatic cancer.
Necrobiotic palisading granulomas associated with breast carcinoma
Authors: Coyne J D
Published: November 2005

Aims:The presence of granulomas within the stroma of carcinomas and in the lymph nodes draining carcinomas has been well described. To date, however, there have been few studies examining the occurrence and relevance of necrobiotic granulomas occurring in association with breast carcinoma.

Methods/Results:Four cases of breast carcinoma with necrobiotic granulomas were examined using periodic acid Schiff and Ziehl Neelsen stains for fungi and tubercle bacilli and with immunohistochemistry using CAM5.2, cytokeratin 7, and cytokeratin AE1/3 for tumour cells. In one case the stroma was involved, in the other three cases the lymph nodes contained necrobiotic granulomas. In two of the cases, one with stromal and one with lymph node involvement, the necrobiotic granulomas contained necrotic tumour cells.

Conclusion:In this study the features of four cases of breast carcinomas with necrobiotic granulomas are examined and their relevance explored. Close scrutiny of such granulomas is necessary to avoid underdiagnosis of metastatic disease.
Small cell sweat gland carcinoma of childhood
Authors: Drut R , Giménez O P , Oliva J
Published: November 2005

Small cell sweat gland carcinoma appears to represent a very unusual histological type of sweat gland anlage tumour presenting in children. The differential diagnosis from other small blue cell tumours involving the skin is often difficult. The present report confirms the original observation describing two patients of 2 and 5 years of age harbouring cutaneous tumours. The histology of these lesions showed a monomorphic proliferation of small cells with a high mitotic rate and areas of necrosis. Immunohistochemically, the cells were negative for desmin, cytokeratin 7, cytokeratin 20, Cam 5.2, CD99, chromogranin, CD56, synaptophysin, and S-100, and focally positive for the pancytokeratin marker AE1/AE3, carcinoembryonic antigen (one case), and neurone specific enolase (one case). The prognosis of this type of tumour seems to be good. As more cases are added, the clinical pathological spectrum of the lesion will become better defined.
Postmortem diagnosis of chronic granulomatous disease: how worthwhile is it?
Authors: Lakshman R , Bruce S , Spencer D A , Crawford D , Galloway A , Cooper P N , Barge D , Roos D , Flood T J , Abinun M
Published: November 2005

A previously healthy 11 year old boy died unexpectedly after a rapid course of progressive pneumonia. Postmortem microbiology and histopathology suggested an underlying diagnosis of chronic granulomatous disease. This was confirmed by neutrophil oxidative burst and gene mutation analysis of other family members, one of whom benefited from early bone marrow transplantation.
Maspin expression in carcinoma ex pleomorphic adenoma
Authors: Martins M T , Altemani A , Freitas L , Araújo V C
Published: November 2005

Aims:To investigate the presence and distribution of the protein maspin in carcinoma ex pleomorphic adenoma (CXPA).

Methods:Maspin expression was studied by means of immunohistochemistry in 16 cases of CXPA, using the labelled polymer method.

Results:According to the extent of invasion, the tumours were subdivided into: intracapsular (five cases), minimally invasive (four cases), and invasive (seven cases). Twelve patients had carcinoma with only epithelial differentiation, whereas four had a malignant myoepithelial component. Non-luminal cells in the duct-like structures of the remnant pleomorphic adenoma were strongly positive for maspin, whereas only a few luminal cells were immunopositive. A few positive cells were seen in the frequent hypocellular and hyalinised areas. Maspin was abundantly expressed, mainly in non-luminal cells, in transitional areas of CXPA with only epithelial differentiation. In frankly carcinomatous areas there was a gradual decrease in maspin expression. Almost all cells were maspin positive in CXPA with a myoepithelial component. When present, luminal cells were in general negative for maspin.

Conclusions:When only epithelial cells undergo malignant transformation, maspin expression is gradually lost. In cases with a myoepithelial component, maspin expression is high, and this might be related to the tumour suppressor activity attributed to this cell.
Involvement of MMP-7 in invasion of pancreatic cancer cells through activation of the EGFR mediated MEK–ERK signal transduction pathway
Authors: Tan X , Egami H , Abe M , Nozawa F , Hirota M , Ogawa M
Published: November 2005

Aims:To clarify the involvement of matrix metalloproteinase-7 (MMP-7) in cell dissociation and the subsequent invasion of pancreatic cancer cells.

Methods:Western blotting, in vitro invasion assay, immunocytochemistry, and immunohistochemistry were performed in pancreatic cancer cell lines or pancreatic cancer tissue.

Results:The active form of the MMP-7 protein was expressed exclusively in the conditioned medium of dissociated (PC-1.0 and AsPC-1) pancreatic cancer cells, whereas proMMP-7 protein was only detected in the conditioned medium of non-dissociated (PC-1 and Capan-2) cells. Both intracellular and conditioned medium localised MMP-7 was greatly reduced by treatment with the epidermal growth factor receptor (EGFR) inhibitor AG1478 and the mitogen activated protein kinase kinase (MEK) inhibitor U0126 in pancreatic cancer cells. MMP-7 treatment significantly induced the disruption of tight junction (TJ) structures and subsequent cell dissociation, and activation of the EGFR mediated MEK– ERK (extracellular signal regulated protein kinase) signalling pathway in the non-dissociated pancreatic cancer cells. Moreover, the strong in vitro invasiveness of dissociated cells was inhibited by AG1478 and U0126 treatment, whereas the weak invasiveness of non-dissociated cells was apparently induced by MMP-7 treatment. In addition, MMP-7 expression was stronger at the invasive front than at the centre of human pancreatic tumours.

Conclusion:MMP-7 is involved in cell dissociation and the subsequent invasion of pancreatic cancer cells. It induces the disruption of TJ structures and forms a positive feedback loop with activation of the EGFR mediated MEK–ERK signalling pathway.
Two cases of inflammatory muscle disease presenting with raised serum concentrations of troponin T
Authors: Hamilton J S , Sharpe P C
Published: November 2005

Troponins T and I are highly sensitive markers of myocardial injury. However, non-cardiac disorders, such as pulmonary embolism, renal failure, subarachnoid haemorrhage, sepsis, eclampsia, chemotherapy, and inflammatory muscle conditions (dermatomyositis and polymyositis), can also result in raised serum troponin concentrations. This article describes two cases that occurred within a month of each other in Craigavon Area Hospital, whereby conditions unrelated to myocardial ischaemia resulted in raised concentrations of cardiac markers. The first patient, in retrospect, underwent unnecessary investigation as an inpatient in the cardiac ward. Experience gained from this case led to more appropriate consultation and management of the second patient.
Frequent overexpression of epidermal growth factor receptor (EGFR) in mammary high grade ductal carcinomas with myoepithelial differentiation
Authors: Shien T , Tashiro T , Omatsu M , Masuda T , Furuta K , Sato N , Akashi-Tanaka S , Uehara M , Iwamoto E , Kinoshita T , Fukutomi T , Tsuda H , Hasegawa T
Published: November 2005

Aims:To evaluate the expression of common biological markers and the epidermal growth factor receptor (EGFR) in mammary high grade ductal carcinomas with myoepithelial differentiation (DCMDs).

Materials/methods:Thirty DCMDs were clinicopathologically and immunohistochemically analysed and compared with 36 control cases of high grade conventional invasive ductal carcinoma (IDC).

Results:EGFR, HER2/neu, oestrogen receptor, progesterone receptor, and p53 expression was seen in 21, one, three, four, and 20 of the 30 DCMDs, compared with eight, nine, 18, 17, and five of the 36 conventional IDCs (p < 0.05), respectively. In 16 of the 30 DCMDs, metastases were found in the brain, lung, bone, and liver, within a maximum of 47 months (mean, 13.9) after initial surgery, whereas only four of the 36 conventional IDCs metastasised to the lung and bone within a maximum of 27 months (mean, 18.0) after initial surgery (p  =  0.0001). There was a significant difference in disease free survival between DCMD and conventional IDC (p  =  0.001). EGFR was frequently overexpressed in DCMD compared with conventional IDC, whereas the expression of HER2/neu and hormone receptors was lower in DCMD. Fluorescent in situ hybridisation revealed that the mean EGFR to chromosome 7 centromere (CEP7) ratio of the 24 DCMD cases available for evaluation was 1.03, and EGFR gene amplification was not detected in the 21 DCMD cases with EGFR overexpression.

Conclusion:Immunohistochemistry for myoepithelial markers and EGFR is useful for the accurate diagnosis and molecular target treatment of high grade DCMD.
mRNA expression of genes involved in lipid efflux and matrix degradation in occlusive and ectatic atherosclerotic disease
Authors: Soumian S , Gibbs R , Davies A , Albrecht C
Published: November 2005

Background:Atherosclerotic plaque behaviour is influenced by intraplaque inflammation, matrix turnover, and the lipid core volume. Peroxisome proliferator activated receptor γ (PPARγ) modulates atherosclerosis by its anti-inflammatory and anti-protease activity. PPARγ promotes lipid efflux through the liver X receptor α (LXRα) and the ATP binding cassette transporter A1 (ABCA1). Matrix metalloproteinase 9 (MMP-9) and cyclooxygenase 2 (COX-2) are implicated in plaque instability.

Aims:To assess the expression of these genes in occlusive and ectatic atherosclerotic disease to determine the relation between genes involved in lipid efflux and matrix degradation.

Methods:Carotid endarterectomy specimens from 16 patients and aneurysm tissue from 16 patients undergoing abdominal aortic aneurysm repair were used. Inferior mesenteric arteries from colectomy specimens from 12 patients served as controls. Total RNA was extracted from pulverised tissue and reverse transcribed into cDNA. Quantitative real time polymerase chain reaction (PCR) was performed using fluorescently labelled probes forABCA1,LXRα,PPARγ,COX-2, andMMP-9.

Results:PPARγexpression was significantly lower in both occlusive and ecstatic atherosclerotic disease (p<0.001), whereasLXRαandABCA1expression was significantly increased (p<0.01).MMP-9expression was significantly increased in diseased tissues (p<0.0001), and values were highest in occlusive disease (p<0.01). The increases inABCA1andMMP-9mRNA were significantly correlated in diseased tissues (p<0.01,r = 0.71 andr = 0.78).COX-2expression was increased in ectatic but low in occlusive disease (p<0.01).

Conclusion:This observational study suggests a role for therapeutic upregulation of PPARγ, which could potentially upregulate lipid efflux through ABCA1 and inhibit matrix degradation through inhibition of MMP-9.
Application of the FICTION technique for the simultaneous detection of immunophenotype and chromosomal abnormalities in routinely fixed, paraffin wax embedded bone marrow trephines: Figure 1
Authors: Korać P , Jones M , Dominis M , Kušec R , Mason D Y , Banham A H , Ventura R A
Published: November 2005

The use of interphase fluorescence in situ hybridisation (FISH) to study cytogenetic abnormalities in routinely fixed paraffin wax embedded tissue has become commonplace over the past decade. However, very few studies have applied FISH to routinely fixed bone marrow trephines (BMTs). This may be because of the acid based decalcification methods that are commonly used during the processing of BMTs, which may adversely affect the suitability of the sample for FISH analysis. For the first time, this report describes the simultaneous application of FISH and immunofluorescent staining (the FICTION technique) to formalin fixed, EDTA decalcified and paraffin wax embedded BMTs. This technique allows the direct correlation of genetic abnormalities to immunophenotype, and therefore will be particularly useful for the identification of genetic abnormalities in specific tumour cells present in BMTs. The application of this to routine clinical practice will assist diagnosis and the detection of minimal residual disease.
FAT, E-cadherin, β catenin, HER 2/neu, Ki67 immunoexpression, and histological grade in intrahepatic cholangiocarcinoma
Authors: Settakorn J , Kaewpila N , Burns G F , Leong A S-Y
Published: November 2005

Aim:To identify surrogate prognostic markers in intrahepatic cholangiocarcinoma (IHCC).

Methods:Thirty one cases of IHCC were graded and immunostained for FAT, Ki67, E-cadherin, β catenin, and HER 2/neu.

Results:Twenty two cases were high grade and 27 had high Ki67 counts. Strong membranous staining of HER 2/neu was found in 10 tumours and reduced membranous E-cadherin and β catenin in 19 and 18 tumours, respectively. Nuclear localisation of β catenin was identified in five tumours and 22 showed weak cytoplasmic staining of FAT. Strong HER 2/neu and weak FAT immunoexpression were significantly correlated with high histological grade (p  =  0.01) and high Ki67 index (p  =  0.03). Upregulation of HER 2/neu was also significantly associated with nuclear localisation of β catenin (p  =  0.01). Reduced membranous β catenin was significantly related to reduced membranous E-cadherin (p  =  0.03), weak staining for FAT (p  =  0.01), and nuclear translocation of β catenin (p  =  0.04).

Conclusions:Reduced immunoexpression of E-cadherin and FAT at their normal membranous location may be potential prognostic markers, and the overexpression of HER 2/neu and β catenin nuclear translocation may have a role in cholangiocarcinogenesis.
A “crackleware” oesophagus
Authors: Westerterp M , Busch O R C , Bergman J J G H M , ten Kate F J W , van Lanschot J J B
Published: November 2005

This case report describes a 70 year old woman with excessive diffuse keratinisation of the oral cavity and oesophagus harbouring a squamous cell carcinoma. This excessive diffuse keratinisation of normally non-keratinised squamous epithelium could not be identified in normally non-keratinised epithelia in other parts of the body (the vagina), arguing against a genetic basis for this disorder. The term “crackleware” oesophagus was used to describe this entity, which has not been described previously in the English literature.