bluuebunny/crossref_metadata_2025 huggingface dataset:
ERP Evidence for Cross-Modal Audiovisual Effects of Endogenous Spatial Attention within Hemifields
Authors: Eimer Martin , Velzen José van , Driver Jon
Published: April 2004

Previous ERP studies have uncovered cross-modal interactions in endogenous spatial attention. Directing attention to one side to judge stimuli from one particular modality can modulate early modality-specific ERP components not only for that modality, but also for other currently irrelevant modalities. However, past studies could not determine whether the spatial focus of attention in the task-irrelevant secondary modality was similar to the primary modality, or was instead diffuse across one hemifield. Here, auditory or visual stimuli could appear at any one of four locations (two on each side). In different blocks, subjects judged stimuli at only one of these four locations, for an auditory (Experiment 1) or visual (Experiment 2) task. Early attentional modulations of visual and auditory ERPs were found for stimuli at the currently relevant location, compared with those at the irrelevant location within the same hemifield, thus demonstrating within-hemifield tuning of spatial attention. Crucially, this was found not only for the currently relevant modality, but also for the currently irrelevant modality. Moreover, these within-hemifield attention effects were statistically equivalent regardless of the task relevance of the modality, for both the auditory and visual ERP data. These results demonstrate that within-hemifield spatial attention for one task-relevant modality can transfer cross-modally to a task-irrelevant modality, consistent with spatial selection at a multimodal level of representation.
The Inferior Frontal Gyrus and Phonological Processing: An Investigation using rTMS
Authors: Nixon Philip , Lazarova Jenia , Hodinott-Hill Iona , Gough Patricia , Passingham Richard
Published: April 2004

Repetitive transcranial magnetic stimulation (rTMS) offers a powerful new technique for investigating the distinct contributions of the cortical language areas. We have used this method to examine the role of the left inferior frontal gyrus (IFG) in phonological processing and verbal working memory. Functional neuroimaging studies have implicated the posterior part of the left IFG in both phonological decision making and subvocal rehearsal mechanisms, but imaging is a correlational method and it is therefore necessary to determine whether this region is essential for such processes. In this paper we present the results of two experiments in which rTMS was applied over the frontal operculum while subjects performed a delayed phonological matching task. We compared the effects of disrupting this area either during the delay (memory) phase or at the response (decision) phase of the task. Delivered at a time when subjects were required to remember the sound of a visually presented word, rTMS impaired the accuracy with which they subsequently performed the task. However, when delivered later in the trial, as the subjects compared the remembered word with a given pseudoword, rTMS did not impair accuracy. Performance by the same subjects on a control task that required the processing of nonverbal visual stimuli was unaffected by the rTMS. Similarly, performance on both tasks was unaffected by rTMS delivered over a more anterior site (pars triangularis). We conclude that the opercular region of the IFG is necessary for the normal operation of phonologically based working memory mechanisms. Furthermore, this study shows that rTMS can shed further light on the precise role of cortical language areas in humans.
Grouping of Sequential Sounds—An Event-Related Potential Study Comparing Musicians and Nonmusicians
Authors: Zuijen Titia L. van , Sussman Elyse , Winkler István , Näätänen Risto , Tervaniemi Mari
Published: April 2004

It is believed that auditory processes governing grouping and segmentation of sounds are automatic and represent universal aspects of music perception (e.g., they are independent of the listener's musical skill). The present study challenges this view by showing that musicians and nonmusicians differ in their ability to preattentively group consecutive sounds. We measured event-related potentials (ERPs) from professional musicians and nonmusicians who were presented with isochronous tone sequences that they ignored. Four consecutive tones in a sequence could be grouped according to either pitch similarity or good continuation of pitch. Occasionally, the tone-group length was violated by a deviant tone. The mismatch negativity (MMN) was elicited to the deviants in both subject groups when the sounds could be grouped based on pitch similarity. In contrast, MMN was only elicited in musicians when the sounds could be grouped according to good continuation of pitch. These results suggest that some forms of auditory grouping depend on musical skill and that not all aspects of auditory grouping are universal.
Digital Evolution in Time-Dependent Fitness Landscapes
Authors: Li Ye , Wilke Claus O.
Published: April 2004

We study the response of populations of digital organisms that adapt to a time-varying (periodic) fitness landscape of two oscillating peaks. We corroborate in general predictions from quasi-species theory in dynamic landscapes, such as adaptation to the average fitness landscape at small periods (high frequency) and quasistatic adaptation at large periods (low frequency). We also observe adaptive phase shifts (time lags between a change in the fitness landscape and an adaptive change in the population) that indicate a low-pass filter effect, in agreement with existing theory. Finally, we witness long-term adaptation to fluctuating environments not anticipated in previous theoretical work.
Evolution of Resource Competition between Mutually Dependent Digital Organisms
Authors: Johnson Tyler J. , Wilke Claus O.
Published: April 2004

We study the emergence and dynamics of competing strains of digital organisms in a world with two depletable resources. Consumption of one resource produces the other resource as a by-product, and vice versa. As a consequence, two types of mutually dependent organisms emerge that each prey on the waste product of the other. In the absence of mutations, that is, in a purely ecological setting, the abundances of the two types of organisms display a wide range of different types of oscillations, from regular oscillations with large amplitude to irregular oscillations with amplitudes ranging from small to large. In this regime, time-averaged abundance levels seem to be controlled by the relative fitness of the organisms in the absence of resources. Under mutational pressure, on the other hand, populations evolve that seem to avoid the oscillations of intermediate to large amplitudes. In this case, the relative fitness of the organisms in the presence of resources plays an important role in the time-averaged abundance levels as well.
Evolution of Robustness in Digital Organisms
Authors: Edlund Jeffrey A. , Adami Christoph
Published: April 2004

We study the evolution of robustness in digital organisms adapting to a high mutation rate. As genomes adjust to the harsh mutational environment, the mean effect of single mutations decreases, up until the point where a sizable fraction (up to 30% in many cases) of the mutations are neutral. We correlate the changes in robustness along the line of descent to changes in directional epistasis, and find that increased robustness is achieved by moving from antagonistic epistasis between mutations towards codes where mutations are, on average, independent. We interpret this recoding as a breakup of linkage between vital sections of the genome, up to the point where instructions are maximally independent of each other. While such a recoding often requires sacrificing some replication speed, it is the best strategy for withstanding high rates of mutation.
Influence of Chance, History, and Adaptation on Digital Evolution
Authors: Wagenaar Daniel A. , Adami Christoph
Published: April 2004

We evolved multiple clones of populations of digital organisms to study the effects of chance, history, and adaptation in evolution. We show that clones adapted to a specific environment can adapt to new environments quickly and efficiently, although their history remains a significant factor in their fitness. Adaptation is most significant (and the effects of history less so) if the old and new environments are dissimilar. For more similar environments, adaptation is slower while history is more prominent. For both similar and dissimilar transfer environments, populations quickly lose the ability to perform computations (the analogue of beneficial chemical reactions) that are no longer rewarded in the new environment. Populations that developed few computational “genes” in their original environment were unable to acquire them in the new environment.
ÜBERLEGUNGEN ZU EINEM KULTFEST DER ALTMESOPOTAMISCHEN GÖTTIN INANNA
Authors: Böck Barbara
Published: April 2004

The present study aims at interpreting a Sumerian hymn pertaining to the cult of the ancient Mesopotamian goddess of love and war, Inanna/Ištar. Though this literary composition belongs to the realm of royal religion, and centres on the relationship between the goddess and the royal personage, the hymn also provides an insight into a cultic feast of rather popular character. The text describes a ritual; its inner logic follows the course of a cultic ceremony. Accordingly, the term "implicit ritual" as opposed to "explicit ritual", or liturgical order, can be applied. Until now the Sumerian hymn in question has been treated mainly from a text critical point of view. Certain aspects of the ritual performance, viz. the playful change of gender roles, are expressed through the epithets of the goddess. Recently, attention has been given to those epithets that allude to the power of the goddess to change her sex, and it has been proposed that they show a shamanistic side of the goddess. In what follows we shall put forward an alternative interpretation of the change of gender roles by using the concept of play and game as intrinsic to a religious system. The cultic feast of the goddess Inanna/Ištar will thus be traced back to a ritual of inversion which serves to reconstitute the moral and social order as well as to consolidate religious belief. Since our hymn is considered to be one of the main sources for the reconstruction of the so-called "sacred marriage" we shall also touch upon this ancient rite.
CONCEIVING THE CANON IN DVAITA VEDANTA: MADHVA'S DOCTRINE OF "ALL SACRED LORE"
Authors: Stoker Valerie
Published: April 2004

The past decade has witnessed a growing scholarly interest in the Veda's status as a canon for precolonial, Brahminical Hinduism. In an effort to refute the notion that Hinduism is a purely Orientalist construct, several scholars have attempted to locate an indigenous set of shared religious beliefs in Brahmins' consistent reference to the Veda as the standard for religious orthodoxy. Yet even as such arguments posit the Veda as a unifying feature for the diverse Hindu tradition, their very emphasis on the Veda's role as a canon reveals a plurality of understandings of the Veda's nature and message. Heeding J.Z. Smith's (1982) assessment of the role of canon in religious traditions, scholars interested in the Veda's significance for Hinduism have analyzed how specific Brahmin communities innovatively reinterpret the Veda to preserve its relevance in the face of changing circumstances. Because these circumstances are often beyond the pale of Brahminical society, scholarly emphasis on the Veda's canonicity historicizes the Brahminical tradition, highlights that tradition's links to other communities, and breaks down the Orientalist monolith. This article contributes to this ongoing academic discussion by considering the historically significant, highly controversial, and yet insufficiently understood construction of the Vedic canon on the part of Tau.lava philosopher and saint, Śrī Madhvācārya (1238-1317). Focusing on Madhva's doctrine of sarvavidyājāta or "the collection of all sacred lore" presented in his R.gvedic commentary, this article examines how Madhva challenges common conceptions of the Vedic canon's external parameters, internal structure, and core truths in ways that still invoke established exegetical norms. I argue that both the success and the controversy surrounding Madhva's version of the canon indicate that the category of Vedic orthodoxy was central to medieval South Indian Brahminical identity. At the same time, however, notions of normative and non-normative Vedic exegesis were being reconsidered in light of changing religious needs.
Frequency and distribution of behaviour of red-necked grebes breeding colonially and in classic territories
Authors: Klatt Paul , Nuechterlein Gary , Buitron Deborah
Published: April 2004

Over the two-year period, 1997 to 1998, nearly half of a population of over 200 red-necked grebes (Podiceps grisegena) breeding within a large lake (2,537 ha) in central Minnesota, chose to opportunistically nest in concentrated groups on large floating mats of cattail (Typha spp.). In this study, we examined how members of this typically territorial grebe species coped with living in a more social environment. The behaviour of pairs that nested close to conspecifics differed from that of solitary pairs throughout the nesting season. Colonial pairs tended to be less likely than solitary birds to leave their nest vacant and unguarded from competitors or predators. During the pre-nesting stage, colonial females and males spent more of their time in aggression than did solitary-nesting birds. However, after a pair established their nest and egg-laying began, female aggression declined dramatically in both colonial and solitary pairs. During the egg-laying period, females spent significantly more time on the nest than did males, while males were more active than females in nest defense. Throughout the incubation period, colonial males remained closer to the nest and their females than did solitary males. In general, birds nesting in close proximity exhibited a compressed use of the space surrounding their investments in the platform, mate, eggs, and even young, all of which may have become more vulnerable to competitors and predators in areas of higher aggregation. Examining how opportunistically colonial species adapt to breeding in close aggregations may provide insight into the early evolution of colonial nesting birds.
Mate availability and somatic condition affect filial cannibalism in a paternal brooding goby
Authors: Iwao Hajime , Okuda Noboru , Ito Sayaka
Published: April 2004

We conducted a laboratory experiment to test two major predictions from a game-theoretical model for the evolution of filial cannibalism in species with paternal care — that parental males are more cannibalistic when their energy reserve is low and that filial cannibalism increases when mate availability is high. We used a freshwater goby, Rhinogobius sp. OR, in which males care for eggs from multiple females in a nest. For each breeding male, we manipulated food ration, sex ratio and nest space: the former to control its energy reserve and the latter two to control its mate availability. The ANOVA showed that all three factors had a significant effect on filial cannibalism, which was facilitated when male somatic condition was poor, the sex ratio was female-biased and the nest space was small. Furthermore, filial cannibalism became more intense with increasing brood size and with decreasing female body size. In conclusion, the parental energy reserve and the quality and availability of mates are important factors affecting filial cannibalism in Rhinogobius sp. OR.
Behavioural effect of (E)-8,(Z)-10-dodecadien-1-ol and (E)-8,(E)-10-dodecadienyl acetate on the upwind orientation of male codling moth, Cydia pomonellato pheromone source
Authors: El-Sayed Ashraf
Published: April 2004

The orientation behaviour of male codling moth, Cydia pomonella (L.) to a pheromone source (E8,E10-12OH, codlemone) with and without E8,Z10-12OH and/or E8,E10-12Ac was investigated in a flight tunnel using a three dimensional video recording system. Both E8,Z10-12OH and E8,E10-12Ac antagonized male attraction when their ratio to codlemone was increased to 20% and 5% respectively. An additive inhibitory effect was observed when both E8,Z10-12OH and/or E8,E10-12Ac were combined with codlemone. Male codling moth flying upwind showed different flight maneuvers in plumes containing codlemone with either E8,Z10-12OH or E8,E10-12Ac. Increasing the release rate of E8,Z10-12OH in codlemone plume to 10 pg/min (i.e., its ratio relative to codlemone was increased to100%) caused males to significantly reduce their flight speeds and angular velocity, similar effects were observed with E8,E10-12Ac when its release rate was increased only to 0.5 pg/min (i.e., its ratio relative to codlemone was increased to 5%). Both E8,Z10-12OH and E8,E10-12Ac caused males to increase their track angles as their concentrations increased in the codlemone plume. However, this effect was mainly due to the significant increase in the course angle for E8,Z10-12OH, and in the drift angle for E8,E10-12Ac. The relevance of these findings in relation to the orientation disruption of codling moth is briefly discussed.
The quantitative genetics of sexual selection in the dung fly Sepsis cynipsea
Authors: Blanckenhorn Wolf , Mühlhäuser Claudia
Published: April 2004

In the common dung or black scavenger fly Sepsis cynipsea (Diptera: Sepsidae) several morphological and behavioural male and female traits interact during mating. Previous studies show that males attempt to mount females without courtship, females use vigorous shaking behaviour in response to male mounting, the duration of shaking is an indicator of both direct and indirect female choice and sexual conflict, and larger males enjoy a mating advantage. We conducted a quantitative genetic paternal half sib study to investigate the genetic underpinnings of these traits, notably body size (the preferred trait) and the associated female preference, and to assess the relative importance of various models generally proposed to account for the evolution of sexually selected traits. Several morphological traits and female shaking duration were heritable, thus meeting a key requirement of all sexual selection models. In contrast, two traits indicative of male persistence in mating were not. Male longevity was also heritable and negatively correlated with his mating effort, suggesting a mating cost. However, the crucial genetic correlation between male body size and female shaking duration, predicted to be negative by both 'good genes' and Fisherian models and positive by the sexual conflict (or chase-away) model, was zero. This could be because of low power, or because of constraints imposed by the genetic correlation structure. Based on our rsults we conclude that discriminating sexual selection models by sole means of quantitative genetics is difficult, if not impossible.
Contest winning and metabolic competence in male bank voles Clethrionomys glareolus
Authors: Labocha Marta , Kruczek Małgorzata , Radwan Jacek , Koteja Paweł , Grabiec Katarzyna
Published: April 2004

Famale bank voles prefer dominant males as mates, and it has been suggested that this preference may benefit females genetically, via increased fitness of their progeny. This requires that male ability to win intrasexual contests is associated with their genetic quality. An important aspect of individual quality is metabolic competence. Here, we investigated whether male ability to win contests is correlated with aerobic capacity (the maximum rate of oxygen consumption) or factorial aerobic scope (the ratio of aerobic capacity to basal metabolic rate [BMR]). The ability to win was assessed as proportion of dominant behaviours in staged contests with five other males, and aerobic capacity was measured both during exercise (swimming) and during cold-exposure trials. Contest winning ability was not correlated with the aerobic capacity (p > 0.6), the factorial metabolic scope (p > 0.25) or BMR (p = 0.24; all the traits were corrected for the effect of body mass). Thus, the results indicate that the trait (male dominance) subject to female preference in the bank vole fails to reveal an important aspect of male quality, i.e. his metabolic competence.
Vocal discrimination of kin and non-kin agemates among lambs
Authors: Sebe Frédéric , Ligout Séverine , Porter Richard
Published: April 2004

Playback experiments were conducted with 4 week old Ile-de-France lambs (Ovis aries) to assess the role of auditory cues in social discrimination. After being habituated to the test enclosure, lambs were individually exposed to bleats from two stimulus individuals. Twin lambs were tested with recorded bleats of their sibling versus an unfamiliar agemate and single lambs with bleats of a familiar agemate versus an unfamiliar lamb. Lambs responded more frequently to the bleats of their sibling (for twin lambs) or of a familiar agemate (for single lambs) than to those of an unfamiliar lamb. Such discriminative responses to the bleats of familiar twins and non-kin lambs suggest that vocalizations may be a sufficient basis for social recognition. Acoustic analyses of the playback bleats revealed significant differences between the signals from the different stimulus lambs and suggest that fundamental frequency may be an important parameter of lambs' individual vocal signatures.
Gender, Capitalism and Globalization
Authors: Acker Joan
Published: April 2004

Gendering the discourse of globalization will help to develop a better understanding of globalization processes and their consequences for women and men. I argue that gender processes and ideologies are embedded in globalizing capitalism in the separation of capitalist production and human reproduction and the corporate claims to non-responsibility for reproduction; in the important role of hegemonic masculinities in globalizing processes, and in the ways that gender serves as a resource for capital. I also discuss some of the consequences for women and men of these processes of globalization.
From Gender as Object to Gender as Verb: Rethinking how Global Restructuring Happens*
Authors: Salzinger Leslie
Published: April 2004

Global restructuring is a gendered process. In transnational production, the creation and allocation of labor power is organized around and in terms of tropes of gendered personhood, and this has consequences for the way production works in general, above and beyond its implications for workers themselves. The paper explores this process through narrating the evolution of a local labor market in Mexico's export-processing (maquila) industry. In so doing, the account reveals globalization to be less linear, obdurate and inevitable than many theories suggest. In this context, managers gendered commitments, desires and understandings prove to be literally counterproductive, undermining industry-wide shop-floor control.
Jun N-terminal kinase promotes proliferation of immature erythroid cells and erythropoietin-dependent cell lines
Authors: Jacobs-Helber Sarah M. , Sawyer Stephen T.
Published: April 2004

Erythropoietin (EPO) is the hormone necessary for development of erythrocytes from immature erythroid cells. EPO activates Jun N-terminal kinase (JNK), a member of the mitogen-activated protein kinase (MAPK) family in the EPO-dependent murine erythroid HCD57 cells. Therefore, we tested if JNK activity supported proliferation and/or survival of these cells. Treatment with the JNK inhibitor SP600125 inhibited JNK activity and EPO-dependent proliferation of HCD57 cells and the human EPO-dependent cell lines TF-1 and UT7-EPO. SP600125 also increased the fraction of cells in G2/M. Introduction of a dominant-negative form of JNK1 inhibited EPO-dependent proliferation in HCD57 cells but did not increase the fraction of cells in G2/M. Constitutive JNK activity was observed in primary murine erythroid progenitors. Treatment of primary mouse bone marrow cells with the SP600125 inhibitor reduced the number of erythroid burst-forming units (BFU-e's) but not the more differentiated erythroid colony-forming units (CFU-e's), and SP600125 protected the BFU-e's from apoptosis induced by cytosine arabinoside, demonstrating that the SP600125 inhibited proliferation of the BFU-e's. Therefore, JNK activity appears to be an important regulator of proliferation in immature, primary erythroid cells and 3 erythroid cell lines but may not be required for the survival or proliferation of CFU-e's or proerythroblasts.
ABC transporter inhibitors that are substrates enhance lentiviral vector transduction into primitive hematopoietic progenitor cells
Authors: Davis Brian M. , Humeau Laurent , Slepushkin Vladimir , Binder Gwendolyn , Korshalla Lauren , Ni Yajin , Ogunjimi E. Oluwakemi , Chang Lan-Fei , Lu Xiaobin , Dropulic Boro
Published: April 2004

High gene transfer efficiencies have been difficult to achieve in hematopoietic progenitor cells (HPCs) but are important to therapeutic success of HPC gene therapy. Efficient gene transfer is especially challenging with use of column-purified vector for clinical application, as opposed to centrifuged vector commonly used for research. We investigated novel approaches to increase transduction by using a clinically applicable protocol and quantities of column-purified lentiviral vector. Recognizing the association of adenosine 5′-triphosphate (ATP)-binding cassette (ABC) transporters with HPC biology, we investigated the effect of transporter inhibitors on transduction. We found the ABC transporter inhibitor verapamil improved transduction efficiency 2- to 6-fold into CD34+ cells isolated from mobilized peripheral blood, bone marrow, and cord blood. Verapamil also improved transduction in human SCID (severe combined immunodeficient) repopulating cell (SRC) transduction 3- to 4-fold, resulting in 80% to 90% transduction levels in mice receiving primary and secondary transplants without alterations in multilineage reconstitution. Additional ABC transporter substrate inhibitors like quinidine, diltiazem, and ritonavir also enhanced transduction 2- to 3-fold, although ABC transporter inhibitors that are not substrates did not. Enhanced transduction was not observed in mature hematopoietic cells, neurospheres, mesenchymal stem cells, or hepatocytes. Enhancement of transduction in HPCs was observed with vesicular stomatitis virus-G (VSV-G)-pseudotyped lentiviral vector but not with vector pseudotyped with RD114. Thus, we present a new approach for efficient delivery to primitive HPCs by VSV-G-pseudotyped lentiviral vectors. (Blood. 2004;104:364-373)
Identification of a novel 14-3-3ζ binding site within the cytoplasmic tail of platelet glycoprotein Ibα
Authors: Mangin Pierre , David Tovo , Lavaud Vincent , Cranmer Susan L. , Pikovski Inna , Jackson Shaun P. , Berndt Michael C. , Cazenave Jean-Pierre , Gachet Christian , Lanza François
Published: April 2004

The glycoprotein Ib-V-IX (GPIb-V-IX) complex interacts with subendothelial von Willebrand factor (VWF) to ensure recruitment of platelets at sites of vascular injury, a process that culminates in integrin αIIbβ3-dependent stable adhesion and spreading. Interaction of the 14-3-3ζ adaptor protein with the C-terminal 606-610 phosphoserine motif of the GPIbα subunit has been implicated in the control of αIIbβ3 activation and cell spreading. In this study, we have examined potentially novel 14-3-3ζ binding sites by expressing mutant forms of GPIbα in Chinese-hamster-ovary (CHO) cells. Analysis of a series of neighboring 11-12 residue deletions identified a critical role for the 580-LVAGRRPSALS-590 sequence in promoting GPIbα-14-3-3ζ interaction. Development of a phosphospecific antibody demonstrated high levels of phosphorylation of the Ser587 and Ser590 residues in resting platelets (which became dephosphorylated during platelet spreading on VWF), and peptides containing these phosphorylated residues effectively displaced 14-3-3ζ from GPIbα. Analysis of single and double alanine substitutions of Ser587 and Ser590 demonstrated a major role for these residues in promoting GPIbα-14-3-3ζ binding. Moreover, these cell lines exhibited a defect in cell spreading on immobilized VWF. These studies demonstrate the existence of a second major 14-3-3ζ binding site within the cytoplasmic tail of GPIbα that has an important functional role in regulating integrin-dependent cell spreading. (Blood. 2004;104:420-427)
Caspase-12: a developmental link between G-protein–coupled receptors and integrin αIIbβ3 activation
Authors: Kerrigan Steven W. , Gaur Meenakshi , Murphy Ronan P. , Shattil Sanford J. , Leavitt Andrew D.
Published: April 2004

Fibrinogen binding by integrin αIIbβ3 is promoted by platelet agonists that increase the affinity and avidity of αIIbβ3 for fibrinogen through a process called “inside-out” signaling. Having previously demonstrated that inside-out activation of αIIbβ3 is defective in murine megakaryocytes that lack the transcription factor NF-E2, we screened for NF-E2–regulated genes that affect αIIbβ3 activation. Caspase-12 is the most down-regulated gene we identified in NF-E2–/– megakaryocytes. Therefore, the role of this protein in αIIbβ3 activation was determined using platelets from caspase-12–/– mice. Despite wild-type levels of αIIbβ3, caspase-12–/– platelets exhibit reduced fibrinogen binding to αIIbβ3 following stimulation by adenosine diphosphate (ADP) or protease-activated receptor 4 (PAR4) receptor-activating peptide. The defect in αIIbβ3 activation is associated with decreased cytosolic free calcium and inositol triphosphate levels, and with reduced aggregation, despite wild-type phospholipase Cβ expression levels. In contrast, agonist-induced surface expression of P-selectin, suppression of cAMP levels following ADP stimulation, and spreading on immobilized fibrinogen are unimpaired. Moreover, although caspase-12 is highly expressed in mature megakaryocytes, it is undetectable in platelets. Taken together, these studies establish that caspase-12 expression in murine megakaryocytes is regulated, directly or indirectly, by NF-E2, and suggest that caspase-12 participates in the development of fully functional signaling pathways linking some G-protein–coupled receptors to αIIbβ3 activation.
Role of the CXCR4/SDF-1 chemokine axis in circulating neutrophil homeostasis
Authors: Suratt Benjamin T. , Petty Joseph M. , Young Scott K. , Malcolm Kenneth C. , Lieber Jonathan G. , Nick Jerry A. , Gonzalo Jose-Angel , Henson Peter M. , Worthen G. Scott
Published: April 2004

The bone marrow is the primary site for neutrophil production and release into the circulation. Because the CXC chemokine receptor-4/stromal derived factor-1 (CXCR4/SDF-1) axis plays a central role in the interactions of hematopoietic stem cells, lymphocytes, and developing neutrophils in the marrow, we investigated whether reciprocal CXCR4-dependent mechanisms might be involved in neutrophil release and subsequent return to the marrow following circulation. Neutralizing antibody to CXCR4 reduced marrow retention of infused neutrophils (45.7% ± 0.5% to 6.9% ± 0.5%) and was found to mobilize neutrophils from marrow (34.4% ± 4.4%). Neutrophil CXCR4 expression and SDF-1-induced calcium flux decreased with maturation and activation of the cells, corresponding to the decreased marrow homing associated with these characteristics in vivo. Infusion of the inflammatory mediator and CXCR2 ligand KC led to mobilization of neutrophils from marrow by itself and was augmented 3-fold by low doses of CXCR4-blocking antibody that otherwise had no mobilizing effect. Examination of KC and SDF-1 calcium signaling demonstrated that the effect of KC may, in part, be due to heterologous desensitization to SDF-1. These results suggest that the CXCR4/SDF-1 axis is critical in circulating neutrophil homeostasis and that it may participate in the rapid release of neutrophils from the marrow during inflammation through a novel interaction with inflammatory CXC chemokines. (Blood. 2004;104:565-571)
Age-related phenotypic and oncogenic differences in T-cell acute lymphoblastic leukemias may reflect thymic atrophy
Authors: Asnafi Vahid , Beldjord Kheira , Libura Marta , Villarese Patrick , Millien Corrine , Ballerini Paola , Kuhlein Emilienne , Lafage-Pochitaloff Marina , Delabesse Eric , Bernard Olivier , Macintyre Elizabeth
Published: April 2004

Postnatal thymic involution occurs progressively throughout the first 3 decades of life. It predominantly affects T-cell receptor (TCR) αβ-lineage precursors, with a consequent proportional increase in multipotent thymic precursors. We show that T-acute lymphoblastic leukemias (T-ALLs) demonstrate a similar shift with age from predominantly TCR expressing to an immature (IM0/δ/γ) stage of maturation arrest. Half demonstrate HOX11, HOX11L2, SIL-TAL1, or CALM-AF10 deregulation, with each being associated with a specific, age-independent stage of maturation arrest. HOX11 and SIL-TAL represent αβ-lineage oncogenes, whereas HOX11L2 expression identifies an intermediate αβ/γδ-lineage stage of maturation arrest. In keeping with preferential αβ-lineage involution, the incidence of SIL-TAL1 and HOX11L2 deregulation decreased with age. In contrast, HOX11 deregulation became more frequent, suggesting longer latency. TAL1/LMO1 deregulation is more frequent in αβ-lineage T-ALL, when it is predominantly due to SIL-TAL1 rearrangements in children but to currently unknown mechanisms in adolescents and adults. LMO2 was more frequently coexpressed with LYL1, predominantly in IM0/δ/γ adult cases, than with TAL1. These age-related changes in phenotype and oncogenic pathways probably reflect progressive changes in the thymic population at risk of malignant transformation.
T-cell receptor–induced phosphorylation of the ζ chain is efficiently promoted by ZAP-70 but not Syk
Authors: Steinberg Marcos , Adjali Oumeya , Swainson Louise , Merida Peggy , Bartolo Vincenzo Di , Pelletier Ludivine , Taylor Naomi , Noraz Nelly
Published: April 2004

Engagement of the T-cell receptor (TCR) results in the activation of Lck/Fyn and ZAP-70/Syk tyrosine kinases. Lck-mediated tyrosine phosphorylation of signaling motifs (ITAMs) in the CD3-ζ subunits of the TCR is an initial step in the transduction of signaling cascades. However, ζ phosphorylation is also promoted by ZAP-70, as TCR-induced ζ phosphorylation is defective in ZAP-70–deficient T cells. We show that this defect is corrected by stable expression of ZAP-70, but not Syk, in primary and transformed T cells. Indeed, these proteins are differentially coupled to the TCR with a 5- to 10-fold higher association of ZAP-70 with ζ as compared to Syk. Low-level Syk-ζ binding is associated with significantly less Lck coupled to the TCR. Moreover, diminished coupling of Lck to ζ correlates with a poor phosphorylation of the positive regulatory tyr352 residue of Syk. Thus, recruitment of Lck into the TCR complex with subsequent ζ chain phosphorylation is promoted by ZAP-70 but not Syk. Importantly, the presence of ZAP-70 positively regulates the TCR-induced tyrosine phosphorylation of Syk. The interplay between Syk and ZAP-70 in thymocytes, certain T cells, and B-chronic lymphocytic leukemia cells, in which they are coexpressed, will therefore modulate the amplitude of antigen-mediated receptor signaling.
HIV-1–specific cytotoxicity is preferentially mediated by a subset of CD8+ T cells producing both interferon-γ and tumor necrosis factor–α
Authors: Lichterfeld Mathias , Yu Xu G. , Waring Michael T. , Mui Stanley K. , Johnston Mary N. , Cohen Daniel , Addo Marylyn M. , Zaunders John , Alter Galit , Pae Eunice , Strick Daryld , Allen Todd M. , Rosenberg Eric S. , Walker Bruce D. , Altfeld Marcus
Published: April 2004

CD8+ T cells play a crucial role in the control of viral infections by direct elimination of infected cells and secretion of a number of soluble factors. Recent data suggest that HIV-1-specific CD8+ T cell subsets may differ in their ability to exert these effector functions. Here, we directly compared the cytokine secretion patterns and cytotoxic capacity of HIV-1-specific CD8+ T cells, using a flow-cytometric cytotoxicity assay based on caspase-3 activation in dying target cells. These experiments revealed considerable intraindividual and interindividual differences among epitope-specific T-cell effector functions: while the frequency of HIV-1-specific CD8+ T cells secreting interferon-γ but no tumor necrosis factor-α (TNF-α) following antigenic stimulation was only weakly correlated to their cytotoxic activity (R = 0.05, P = .57), a subset of CD8+ T cells secreting both inter-feron-γ and TNF-α was substantially more strongly associated with cytotoxicity (R = 0.67, P < .001). This subset of CD8+ T cells also exhibited stronger intracellular perforin expression and more pronounced direct ex vivo HIV-1-specific cytoxicity than CD8+ T cells secreting solely interferon-γ following sorting of these subpopulations according to their cytokine profile. These results suggest that HIV-1-specific cytotoxicity of CD8+ T cells is preferentially mediated by a subset of CD8+ T cells secreting both interferon-γ and TNF-α. (Blood. 2004;104:487-494)
Positive and negative regulatory roles of the WW-like domain in TEL-PDGFβR transformation
Authors: Chen Jing , Williams Ifor R. , Kutok Jeffery L. , Duclos Nicole , Anastasiadou Ema , Masters Shane C. , Fu Haian , Gilliland D. Gary
Published: April 2004

TEL-platelet-derived growth factor-β receptor (TEL-PDGFβR) is expressed in chronic myelomonocytic leukemias associated with t(5;12)(q33;p13), and the fusion tyrosine kinase retains a conserved WW-like domain in the PDGFβR autoinhibitory juxtamembrane region. Here we report that mutation of the 2 conserved tryptophan residues of the WW-like domain has opposing effects on TELPDGFβR kinase activation. Alanine substitution of W593, essential for protein-protein interaction in the context of other WW domains, impaired TEL-PDGFβR-mediated transformation of hematopoietic cells due to inhibition of TEL-PDGFβR kinase activity. In contrast, alanine substitution of W566, essential for structural integrity of WW domain in other contexts, had no effect on TEL-PDGFβR activation and oncogenic activity. Surprisingly, however, the W566A mutation suppressed the W593A phenotype. Double mutant W566A/W593A was indistinguishable from the wild-type fusion protein with regard to kinase activity, ability to confer factor-independent growth to Ba/F3 cells, or ability to induce a myeloproliferative disease in mice. Additional mutational analysis identified other substitutions within the WW-like domain in addition to W566A that could also suppress the W593A phenotype, including mutations predicted to diminish the autoinhibitory function of the juxtamembrane region. Therefore, the WW-like domain in the context of TELPDGFβR may have both positive and negative regulatory roles in kinase activation. (Blood. 2004;104:535-542)
Proteomics applied to the clinical follow-up of patients after allogeneic hematopoietic stem cell transplantation
Authors: Kaiser Thorsten , Kamal Haytham , Rank Andreas , Kolb Hans-Jochem , Holler Ernst , Ganser Arnold , Hertenstein Bernd , Mischak Harald , Weissinger Eva Maria
Published: April 2004

A phase 1 diagnostic study was performed to evaluate a novel technology for clinical proteom research based on capillary electrophoresis and mass spectrometry. Urine from 40 patients after hematopoietic stem cell transplantation (HSCT; 35 allogeneic, 5 autologous) and 5 patients with sepsis was collected for a period of 100 days and analyzed. More than 1000 different polypeptides could be detected in individual samples. Polypeptide patterns excreted in the urine of patients were significantly different from those of healthy volunteers. No significant differences were detected comparing different conditioning regimens. The aim of this study was to identify polypeptide patterns functioning as early indicators of graft-versus-host disease (GVHD). Eighteen patients developed GVHD after allogeneic HSCT. Sixteen differentially excreted polypeptides formed a pattern of early GVHD markers, allowing discrimination of GVHD from patients without complications with 82% specificity and 100% sensitivity, cross-validated. Inclusion of 13 sepsis-specific polypeptides allowed us to distinguish sepsis from GVHD with a specificity of 97% and a sensitivity of 100%. Sequencing 2 prominent GVHD-indicative polypeptides led to the identification of a peptide from leukotriene A4 hydrolase and a peptide from serum albumin. The data reveal that capillary electrophoresis and mass spectrometry allow identification of biomarkers for a variety of diseases or related complications. (Blood. 2004;104:340-349)
Apoptosis of human primary B lymphocytes is inhibited by N-acetyl-L-cysteine
Authors: Rosati Emanuela , Sabatini Rita , Ayroldi Emira , Tabilio Antonio , Bartoli Andrea , Bruscoli Stefano , Simoncelli Costantino , Rossi Ruggero , Marconi Pierfrancesco
Published: April 2004

Thiols are important molecules to control apoptosis. This study examined the effect of N-acetyl-L-cysteine (NAC) on in vitro spontaneous apoptosis of human tonsillar B lymphocytes (TBL). Results show that NAC inhibits TBL apoptosis and maintains their survival in vitro. The antiapoptotic action of NAC is progressively reduced when its addition to culture is delayed, is reversible, and is not blocked by cycloheximide. The antiapoptotic activity of NAC is associated with its ability to inhibit caspase-3 and -7 proteolytic processing, DNA-fragmentation factor 45 cleavage, and DNA fragmentation. Furthermore, NAC inhibits BID cleavage and cytochrome c release from mitochondria and increases the expression of Bcl-2 and BclXL survival proteins. However, it has no effect on caspase-9 cleavage and increases that of caspase-8 and poly(adenosine 5′-diphosphate-ribose)polymerase. We conclude that NAC-induced inhibition of TBL apoptosis is associated with inhibition of caspase-3 and -7 processing and is accompanied by changes in several regulatory components of the apoptotic process. These results pose the question of whether microenvironment thiols may in part contribute to in vivo B cell survival.
FcγRIIa expression with FcγRI results in C-reactive protein- and IgG-mediated phagocytosis
Authors: Bodman-Smith Katherine B , Gregory Rachel E , Harrison Patrick T , Raynes John G
Published: April 2004

C-reactive protein (CRP) is a pattern-recognition molecule, which can bind to phosphorylcholine and certain phosphorylated carbohydrates found on the surface of a number of microorganisms. CRP has been shown recently to bind human Fc receptor for immunoglobulin G (IgG; FcγR)I and mediate phagocytosis and signaling through the γ-chain. To date, binding of monomeric CRP to FcγRII has been contentious. We demonstrate that erythrocytes opsonized with CRP bind FcγRIIa-transfected COS-7 cells. In addition, we demonstrate that FcγRI can use FcγRIIa R131 and H131 to phagocytose erythrocytes coated with IgG or purified or recombinant CRP in the absence of the γ-chain. COS-7 cells expressing FcγRIIa or FcγRI alone did not phagocytose opsonized erythrocytes. Such phagocytosis required the cytoplasmic domain of FcγRIIa, as mutation of tyrosine at position 205 and truncation of the cytoplasmic domain from the end of the transmembrane region (position 206), resulting in the loss of the immunoreceptor tyrosine activatory motif, abrogated phagocytosis. FcγRIIa R131 was more efficient than FcγRIIa H131 at mediating CRP-dependent phagocytosis.
Membrane receptor-mediated apoptosis and caspase activation in the differentiated EoL-1 eosinophilic cell line
Authors: Al-Rabia Mohammed W , Blaylock Morgan G , Sexton Darren W , Walsh Garry M
Published: April 2004

Caspases are key molecules in the control of apoptosis, but relatively little is known about their contribution to eosinophil apoptosis. We examined caspase-3, -8, and -9 activities in receptor ligation-dependent apoptosis induction in the differentiated human eosinophilic cell line EoL-1. Differentiated EoL-1 exhibited bi-lobed nuclei, eosinophil-associated membrane receptors, and basic granule proteins. Annexin-V fluorescein isothiocyanate binding to EoL-1 revealed significant (P<0.01) apoptosis induction in cells cultured for 20 h with monoclonal antibodies (mAb) specific for CD45 (71%±4.3), CD45RA (58%±2.3), CD45RB (68%±2.4), CD95 (47%±2.6), and CD69 (52%±2.1) compared with control (23%±1.6) or CD45RO mAb (27%±3.9). The pan-caspase inhibitor Z-Val-Ala-Asp-fluoromethylketone (fmk) and inhibitors of caspase-8 (Z-Ile-Glu-Thr-Asp-fmk) and caspase-9 (Z-Leu-Glu-His-Asp-fmk) significantly inhibited mAb-induced apoptosis of EoL-1 but had no effect on constitutive (baseline) apoptosis at 16 and 20 h. Caspase activity was analyzed using the novel CaspaTag™ technique and flow cytometry. EoL-1 treated with pan-CD45, CD45RA, CD45RB, and CD95 mAb exhibited caspase-3 and -9 activation at 12 h post-treatment, which increased at 16 and 20 h. Activated caspase-8 was detected 12 and 16 h after ligation with CD45, CD45RA, CD45RB, and CD95 mAb followed by a trend toward basal levels at 20 h. CD69 ligation resulted in caspase-3 activation, a modest but significant activation of caspase-8, and a loss in mitochondrial transmembrane potential but had no significant effect on activation of caspase-9. Thus, the intrinsic and extrinsic caspase pathways are involved in controlling receptor ligation-mediated apoptosis induction in human eosinophils, findings that may aid the development of a more targeted, anti-inflammatory therapy for asthma.
Mechanism of apoptosis induced by S100A8/A9 in colon cancer cell lines: the role of ROS and the effect of metal ions
Authors: Ghavami Saeid , Kerkhoff Claus , Los Marek , Hashemi Mohammad , Sorg Clemens , Karami-Tehrani Fatemeh
Published: April 2004

The protein complex S100A8/A9, abundant in the cytosol of neutrophils, is secreted from the cells upon cellular activation and induces apoptosis in tumor cell lines and normal fibroblasts in a zinc-reversible manner. In the present study, we present evidence that the S100A8/A9 also exerts its apoptotic effect by a zinc-independent mechanism. Treatment of the colon carcinoma cells with different concentrations of human S100A8/A9 or the metal ion chelator diethylenetriaminepentacetic acid (DTPA) resulted in a significant increase of cell death. Annexin V/phosphatidylinositol and Hoechst 33258 staining revealed that cell death was mainly of the apoptotic type. A significant increase in the activity of caspase-3 and -9 was observed in both cell lines after treatment. Caspase-8 activation was negligible in both cell lines. The cytotoxicity/apoptotic effect of human S100A8/A9 and DTPA was inhibited significantly (P<0.05) by Zn+2 and Cu+2, more effectively than by Ca2+ and Mg2+. The antioxidant N-acetyl-L-cysteine inhibited the cytotoxicity/apoptotic effect of S100A8/A9 and DTPA. However, as a result of the different time-courses of both agents and that the S100A8/A9-induced apoptosis was not completely reversed, we conclude that S100A8/A9 exerts its apoptotic effect on two colon carcinoma cell lines through a dual mechanism: one via zinc exclusion from the target cells and the other through a yet-undefined mechanism, probably relaying on the cell-surface receptor(s).