bluuebunny/crossref_metadata_2025_split huggingface dataset:
Subtype‐specific actions of β‐amyloid peptides on recombinant human neuronal nicotinic acetylcholine receptors (α7, α4β2, α3β4) expressed in Xenopus laevis oocytes
Authors: Pym Luanda , Kemp Mark , Raymond‐Delpech Valérie , Buckingham Steven , Boyd C A R , Sattelle David 
Published: September 2005

Two‐electrode voltage‐clamp electrophysiology has been used to study the actions of two amyloid peptides (Aβ1–42, Aβ1–40) on α7, α4β2 and α3β4 recombinant human neuronal nicotinic acetylcholine receptors (nicotinic AChRs), heterologously expressed in Xenopus laevis oocytes.
The application of Aβ1–42 or Aβ1–40 (1 pM–100 nM) for 5 s does not directly activate expressed human α7, α4β2 or α3β4 nicotinic AChRs.
Aβ1–42 and Aβ1–40 are antagonists of α7 nicotinic AChRs. For example, 10 nM Aβ1–42 and Aβ1–40 both reduced the peak amplitude of currents recorded (3 mM ACh) to 48±5 and 45±10% (respectively) of control currents recorded in the absence of peptide. In both the cases the effect is sustained throughout a 30 min peptide application and is poorly reversible.
Aβ1–42 and Aβ1–40 (10 nM) enhance currents recorded in response to ACh (3 mM) from oocytes expressing α4β2 nicotinic AChRs by 195±40 and 195±41% respectively. This effect is transient, reaching a peak after 3 min and returning to control values after a 24 min application of 10 nM Aβ1–42. We observe an enhancement of 157±22% of control ACh‐evoked current amplitude in response to 100 nM Aβ1–42 recorded from oocytes expressing α4β2 nicotinic AChRs.
Aβ1–42 and Aβ1–40 (10 nM) were without antagonist actions on the responses of α3β4 nicotinic AChRs to ACh (1 nM–3 mM).

British Journal of Pharmacology (2005) 146, 964–971. doi:10.1038/sj.bjp.0706403
DSP1, a Drosophila HMG protein, is involved in spatiotemporal expression of the homoeotic gene Sex combs reduced
Authors: Rappailles Aurélien , Decoville Martine , Locker Daniel 
Published: September 2005

Background information. The Pc‐G (Polycomb group) and trx‐G (trithorax group) genes play a key role in the regulation of the homoeotic genes. The homoeotic gene Scr (Sex combs reduced) contained in the Antennapedia complex specifies segmental identity of the labial and prothoracic segments in Drosophila. Regulation of Scr requires the action of different enhancer elements spread over several kilobases. We previously identified an HMGB (high mobility group)‐like protein DSP1 (dorsal switch protein 1), which works like a trx‐G protein for the normal Scr expression.Results. In the present study, we attempted to characterize the regulatory sequences involved in the maintenance of the Scr activation by DSP1. We report here, using a transgenic line for the Scr10.0XbaI‐regulatory element, that lack of DSP1 affects the function of a reporter gene in legs' imaginal discs but not in embryos. We show by immunolocalization that DSP1 is recruited on polytene chromosomes to the insertion site of the transgene. Moreover, using chromatin immunoprecipitation experiments, we identify two regions of 1 kb in Scr10.0XbaI as the main DSP1 targets.Conclusion. These results provide strong evidence that the Scr gene expression is influenced by direct interaction between DSP1 and two Scr regulation elements. In addition, our results show that this interaction undergoes dynamic changes during development.
Interaction of SP-A (surfactant protein A) with bacterial rough lipopolysaccharide (Re-LPS), and effects of SP-A on the binding of Re-LPS to CD14 and LPS-binding protein
Authors: García-Verdugo Ignacio , Sánchez-Barbero Fernando , Soldau Katrin , Tobias Peter S. , Casals Cristina 
Published: September 2005

SP-A (surfactant protein A) is a lipid-binding collectin primarily involved in innate lung immunity. SP-A interacts with the bacterial rough LPS (lipopolysaccharide) Re-LPS (Re595 mutant of LPS from Salmonella minnesota), but not with smooth LPS. In the present study, we first examined the characteristics of the interaction of human SP-A with Re-LPS. Fluorescence intensity and anisotropy measurements of FITC-labelled Re-LPS in the presence and absence of SP-A indicated that SP-A bound to Re-LPS in solution in a Ca2+-independent manner, with a dissociation constant of 2.8×10−8 M. In the presence of calcium, a high-mobility complex of SP-A and [3H]Rb-LPS (Rb mutant of LPS from Escherichia coli strain LCD 25) micelles was formed, as detected by sucrose density gradients. Re-LPS aggregation induced by SP-A was further characterized by light scattering. On the other hand, human SP-A inhibited TNF-α (tumour necrosis factor-α) secretion by human macrophage-like U937 cells stimulated with either Re-LPS or smooth LPS. We further examined the effects of human SP-A on the binding of Re-LPS to LBP (LPS-binding protein) and CD14. SP-A decreased the binding of Re-LPS to CD14, but not to LBP, as detected by cross-linking experiments with 125I-ASD-Re-LPS [125I-labelled sulphosuccinimidyl-2-(p-azidosalicylamido)-1,3-dithiopropionate derivative of Re-LPS] and fluorescence analysis with FITC-Re-LPS. When SP-A, LBP and CD14 were incubated together, SP-A reduced the ability of LBP to transfer 125I-ASD-Re-LPS to CD14. These SP-A effects were not due to the ability of SP-A to aggregate Re-LPS in the presence of calcium, since they were observed in both the absence and the presence of calcium. These studies suggest that SP-A could contribute to modulate Re-LPS responses by altering the competence of the LBP–CD14 receptor complex.
Human Rhesus B and Rhesus C glycoproteins: properties of facilitated ammonium transport in recombinant kidney cells
Authors: Zidi-Yahiaoui Nedjma , Mouro-Chanteloup Isabelle , D'Ambrosio Anne-Marie , Lopez Claude , Gane Pierre , Le Van Kim Caroline , Cartron Jean-Pierre , Colin Yves , Ripoche Pierre 
Published: September 2005

The mammalian Rh (Rhesus) protein family belongs to the Amt/Mep (ammonia transporter/methylammonium permease)/Rh superfamily of ammonium transporters. Whereas RhCE, RhD and RhAG are erythroid specific, RhBG and RhCG are expressed in key organs associated with ammonium transport and metabolism. We have investigated the ammonium transport function of human RhBG and RhCG by comparing intracellular pH variation in wild-type and transfected HEK-293 (human embryonic kidney) cells and MDCK (Madin–Darby canine kidney) cells in the presence of ammonium (NH4+/NH3) gradients. Stopped-flow spectrofluorimetry analysis, using BCECF [2′,7′-bis-(2-carboxyethyl)-5(6)-carboxyfluorescein] as a pH-sensitive probe, revealed that all cells submitted to inwardly or outwardly directed ammonium gradients exhibited rapid alkalinization or acidification phases respectively, which account for ammonium movements in transfected and native cells. However, as compared with wild-type cells known to have high NH3 lipid permeability, RhBG- and RhCG-expressing cells exhibited ammonium transport characterized by: (i) a five to six times greater kinetic rate-constant; (ii) a weak temperature-dependence; and (iii) reversible inhibition by mercuric chloride (IC50: 52 μM). Similarly, when subjected to a methylammonium gradient, RhBG- and RhCG-expressing cells exhibited kinetic rate constants greater than those of native cells. However, these constants were five times higher for RhBG as compared with RhCG, suggesting a difference in substrate accessibility. These results, indicating that RhBG and RhCG facilitate rapid and low-energy-dependent bi-directional ammonium movement across the plasma membrane, favour the hypothesis that these Rh glycoproteins, together with their erythroid homologue RhAG [Ripoche, Bertrand, Gane, Birkenmeier, Colin and Cartron (2005) Proc. Natl. Acad. Sci. U.S.A. 101, 17222–17227] constitute a family of NH3 channels in mammalian cells.
AS160, the Akt substrate regulating GLUT4 translocation, has a functional Rab GTPase-activating protein domain
Authors: Mîinea Cristinel P. , Sano Hiroyuki , Kane Susan , Sano Eiko , Fukuda Mitsunori , Peränen Johan , Lane William S. , Lienhard Gustav E. 
Published: September 2005

Recently, we described a 160 kDa protein (designated AS160, for Akt substrate of 160 kDa) with a predicted Rab GAP (GTPase-activating protein) domain that is phosphorylated on multiple sites by the protein kinase Akt. Phosphorylation of AS160 in adipocytes is required for insulin-stimulated translocation of the glucose transporter GLUT4 to the plasma membrane. The aim of the present study was to determine whether AS160 is in fact a GAP for Rabs, and, if so, what its specificity is. We first identified a group of 16 Rabs in a preparation of intracellular vesicles containing GLUT4 by MS. We then prepared the recombinant GAP domain of AS160 and examined its activity against many of these Rabs, as well as several others. The GAP domain was active against Rabs 2A, 8A, 10 and 14. There was no significant activity against 14 other Rabs. GAP activity was further validated by the finding that the recombinant GAP domain with the predicted catalytic arginine residue replaced by lysine was inactive. Finally, it was found by immunoblotting that Rabs 2A, 8A and 14 are present in GLUT4 vesicles. These results indicate that AS160 is a Rab GAP, and suggest novel Rabs that may participate in GLUT4 translocation.
WNK lies upstream of kinases involved in regulation of ion transporters
Authors: Gamba Gerardo 
Published: September 2005

Two members of a recently discovered family of protein kinases {WNK1 and WNK4 [with no K (lysine) kinases-1 and -4]} are the cause of an inherited disease known as pseudohypoaldosteronism type II that features arterial hypertension. The family is known as WNK due to a lack of the invariant catalytic lysine in kinase subdomain II. The mechanisms by which WNKs regulate blood pressure are beginning to be understood at the physiological level from recent studies showing effects of WNK4 on several plasma membrane co-transporters and ion channels. However, little is known about the function of WNKs at the biochemical level. In this issue of the Biochemical Journal, Vitari et al. have shown that WNK1 and WNK4 interact with other kinases, SPAK (STE20/SPS1-related proline/alanine-rich kinase) and OSR1 (oxidative stress response kinase-1), which are involved in the regulation of ion transporters. WNK1 and WNK4 phosphorylate SPAK and OSR1, which in turn phosphorylate the N-terminal domain of the basolateral Na+–K+–2Cl− co-transporter, NKCCl. The phosphorylation site involved in SPAK or OSR1 activation is identified as a threonine residue within the T-loop.
Serum levels of osteoprotegerin and RANKL in patients with ST elevation acute myocardial infarction
Authors: Crisafulli Alessandra , Micari Antonio , Altavilla Domenica , Saporito Francesco , Sardella Aurora , Passaniti Maria , Raffa Santi , D'Anneo Gaspare , Lucà Fabiana , Mioni Chiara , Arrigo Francesco , Squadrito Francesco 
Published: September 2005

OPG (osteoprotegerin) has been suggested to have an important role in atherogenesis and vascular calcification. In the present study, we have investigated serum OPG and RANKL (receptor activator of nuclear factor κB ligand) concentrations in patients with ST elevation AMI (acute myocardial infarction) and established CAD (coronary artery disease). OPG and RANKL were measured in 58 male patients hospitalized in the coronary care unit with ST elevation AMI, in 52 asymptomatic male patients with an established diagnosis of CAD and in 52 healthy male controls. These last two groups were matched with the AMI patients for age and body mass index. OPG was significantly (P&lt;0.05) higher in patients with AMI at 1 h after AMI (8.04±4.86 pmol/l) than in both patients with established CAD (4.92±1.65 pmol/l) and healthy subjects (3.15±1.01 pmol/l). Subjects with established CAD had significantly (P&lt;0.05) increased OPG levels compared with controls. RANKL levels in patients with established CAD (0.02±0.05 pmol/l) and with AMI (0.11±0.4 pmol/l) were significantly (P&lt;0.05) lower compared with controls (0.32±0.35 pmol/l). In the AMI group, OPG decreased significantly (P&lt;0.05) at 1 and 4 weeks after infarction (8.04±4.86 compared with 6.38±3.87 and 6.55±2.6 pmol/l respectively), but OPG levels, either at 1 h or 1–4 weeks after AMI, remained significantly (P&lt;0.05) higher compared with established CAD (4.92±1.65 pmol/l) and controls (3.15±1.01 pmol/l). Our data show for the first time that OPG levels are increased in ST elevation AMI within 1 h of infarction. Whether the increase in OPG is a consequence or a causal factor of plaque destabilization deserves further investigation.
Endothelial function and baroreflex sensitivity according to the oral glucose tolerance test in patients with coronary artery disease and normal fasting glucose levels
Authors: Wykretowicz Andrzej , Guzik Przemysław , Bartkowiak Grzegorz , Krauze Tomasz , Kąsinowski Ryszard , Dziarmaga Mieczysław , Wesseling Karel H. , Wysocki Henryk 
Published: September 2005

Endothelial dysfunction and reduced BRS (baroreflex sensitivity) may be present in patients with CAD (coronary artery disease). The normal fasting glucose level does not exclude abnormal glucose metabolism in patients with CAD. The aim of present study was to evaluate endothelial function and BRS according to glucose metabolism in patients with normal fasting plasma glucose and stable CAD subjected to PTCA (percutaneous transluminal coronary angioplasty). Forty-six consecutive patients who underwent elective PTCA were studied (37 men; mean age 56 years). Endothelial function was assessed non-invasively using the arterial vasodilator response to salbutamol (albuterol). BRS was measured using a cross-correlation method. The extent of coronary narrowing was estimated by calculation of the Gensini score. All patients underwent a 75 g OGTT (oral glucose tolerance test). IGT (impaired glucose tolerance) or diabetes was present in approx. 60% of patients. The vasodilator response to salbutamol, as a measure of endothelial dysfunction, was significantly impaired in patients with IGT or diabetes compared with those with normal glucose tolerance (−0.5±1.6% compared with −7.9±2.2; P=0.01). Glucose metabolism and age were significant predictors of endothelial dysfunction (R2=35.2%, P=0.02). BRS did not differ significantly between patients with normal glucose tolerance and those with IGT or diabetes (6.9±1.2 compared with 6.1±0.6 ms/mmHg respectively; P=0.669). BRS was negatively correlated with age (r=−0.34, P=0.021) and the Gensini score (r=−0.34, P=0.022). The significant predictors of BRS were Gensini score, age and past myocardial infarction (R2=37.02%, P=0.002). Patients with established CAD, normal fasting glucose and IGT or diabetes demonstrated impaired endothelial function which did not correlate with the extent of coronary artery involvement. Conversely, BRS in the study population was not affected by glucose metabolism, but showed an interaction with the extent of coronary narrowing.
Lower bounds for the spectral function and for the remainder in local Weyl’s law on manifolds
Authors: Jakobson Dmitry , Polterovich Iosif 
Published: September 2005

We announce asymptotic lower bounds for the spectral function of the Laplacian and for the remainder in the local Weyl’s law on Riemannian manifolds. In the negatively curved case, methods of thermodynamic formalism are applied to improve the estimates. Our results develop and extend the unpublished thesis of A. Karnaukh. We discuss some ideas of the proofs; for complete proofs see our extended paper on the subject.
A non-invasive method forin situquantification of subpopulation behaviour in mixed cell culture
Authors: MacArthur Ben D , Tare Rahul S , Please Colin P , Prescott Philip , Oreffo Richard O.C 
Published: September 2005

Ongoing advances in quantitative molecular- and cellular-biology highlight the need for correspondingly quantitative methods in tissue-biology, in which the presence and activity of specific cell-subpopulations can be assessedin situ. However, many experimental techniques disturb the natural tissue balance, making it difficult to draw realistic conclusions concerningin situcell behaviour. In this study, we present a widely applicable and minimally invasive method which combines fluorescence cell labelling, retrospective image analysis and mathematical data processing to detect the presence and activity of cell subpopulations, using adhesion patterns in STRO-1 immunoselected human mesenchymal populations and the homogeneous osteoblast-like MG63 continuous cell line as an illustration.Adhesion is considered on tissue culture plastic and fibronectin surfaces, using cell area as a readily obtainable and individual cell specific measure of spreading. The underlying statistical distributions of cell areas are investigated and mappings between distributions are examined using a combination of graphical and non-parametric statistical methods. We show that activity can be quantified in subpopulations as small as 1% by cell number, and outline behaviour of significant subpopulations in both STRO-1+/−fractions. This method has considerable potential to understandin situcell behaviour and thus has wide applicability, for example in developmental biology and tissue engineering.
An adaptive polynomial based forward prediction algorithm for multi-actuator real-time dynamic substructuring
Authors: Wallace M.I , Wagg D.J , Neild S.A 
Published: September 2005

Real-time dynamic substructuring is a novel experimental technique used to test the dynamic behaviour of complex structures. The technique involves creating a hybrid model of the entire structure by combining an experimental test piece—the substructure—with a set of numerical models. In this paper we describe a multi-actuator substructured system of a coupled three mass–spring–damper system and use this to demonstrate the nature of delay errors which can first lead to a loss of accuracy and then to instability of the substructuring algorithm.
Synchronization theory and delay compensation are used to show how the delay errors, present in the transfer systems, can be minimized by online forward prediction. This new algorithm uses a more generic approach than the single step algorithms applied to substructuring thus far, giving considerable advantages in terms of flexibility and accuracy. The basic algorithm is then extended by closing the control loop resulting in an error driven adaptive feedback controller which can operate with no prior knowledge of the plant dynamics. The adaptive algorithm is then used to perform a real substructuring test using experimentally measured forces to deliver a stable substructuring algorithm.
A power flow mode theory based on a system's damping distribution and power flow design approaches
Authors: Xiong Ye-Ping , Xing J.T , Price W.G 
Published: September 2005

A power flow mode theory is developed to describe the natural power flow behaviour of a dynamic system based on its inherent damping distribution. The system's characteristic-damping matrix is constructed and it is shown that the eigenvalues and eigenvectors of this matrix identify natural power flow characteristics. These eigenvectors, or power flow mode vectors, are chosen as a set of base-vectors spanning the power flow space and completely describe the power flow in the system. The generalized coordinate of the velocity vector decomposed in this space defines the power flow response vector. A time-averaged power flow expression and theorems relating to its estimation are presented.
Based on this theory, power flow design approaches are proposed to identify energy flow patterns satisfying vibration control requirements. The mode control factor defines the measure of the correlation between a power flow mode and a natural vibration mode of the system. Power flow design theorems are presented providing guidelines to construct damping distributions maximizing power dissipation or to suppress/retain a particular vibration mode and/or a motion.
The developed damping-based power flow mode theory is compared with a mobility-based power flow model. It is shown that the proposed power flow model provides insight into the power flow dissipation mechanisms in dynamic systems.
Examples are presented to demonstrate the applicability of the power flow mode theory and the power flow design approach. These examples demonstrate the generality of the theory, including non-symmetric damping matrices, and illustrate power flow design applications through modifications of the system's damping distribution using passive and/or active control components.
Moon orientation in adult and young sandhoppers under artificial light
Authors: Ugolini Alberto , Boddi Vieri , Mercatelli Luca , Castellini Carlo 
Published: September 2005

Our experiments, carried out at night and during the day on adults and laboratory-born young of the sandhopperTalitrus saltator, deal with the identification and use of the moon as an orientating factor. Sandhoppers were released in an apparatus (a Plexiglas dome) that produced a scenario similar to the natural one (with artificial sky, moon or sun illuminated at different intensities).When tested at night, the adult and young sandhoppers used the artificial moon like the natural one, independently of the intensity of illumination of the artificial sky and moon. In other words, sandhoppers tested at night always identified the artificial moon as the moon and never as the sun. In daytime releases, the seaward orientation failed at low intensities of artificial sky and sun illumination (3.07 and 1.55 μW cm2, respectively), whereas the sun compass was used effectively at higher levels of artificial sun and sky illumination. The innate ability of moon compass orientation in inexpert young sandhoppers was demonstrated even under artificial light.
Barriers and distances as determinants for the evolution of bird migration links: the arctic shorebird system
Authors: Henningsson Sara S , Alerstam Thomas 
Published: September 2005

We analysed migratory connectivity between different winter quarters and breeding sectors in the circumpolar tundra region for arctic shorebirds, in relation to migratory distances and ecological barriers. Total distances and barriers were calculated and measured for all potential migratory orthodrome links between 10 selected winter regions and 12 breeding sectors. The migratory segment between the northernmost stopover site and the breeding area, associated with the entry to and exit from the tundra during spring and autumn migration, respectively, was also identified and measured for each potential link.The analysis indicated that the evolution of migratory links among arctic shorebirds is constrained not by distance as such but by distance across ecological barriers, possibly because of the complex adaptations required for barrier crossing and extensive detour migration (and in a few cases because barrier distances exceed the birds' theoretical flight range capacity). A particularly pronounced barrier effect of the Arctic Ocean, as apparent from a sharp decline in migratory connectivity between the opposite sides of the Arctic Ocean, may reflect a crucial importance of favourable entry and exit conditions for successfully occupying different sectors of the tundra breeding area by shorebirds from winter regions situated at widely different total distances in both the southern and northern hemispheres.