bluuebunny/crossref_metadata_2025_split huggingface dataset:
Early embryonic expression of ion channels and pumps in chick and Xenopus development
Authors: Rutenberg Joshua , Cheng Shing‐Ming , Levin Michael 
Published: December 2002

AbstractAn extensive body of literature implicates endogenous ion currents and standing voltage potential differences in the control of events during embryonic morphogenesis. Although the expression of ion channel and pump genes, which are responsible for ion flux, has been investigated in detail in nervous tissues, little data are available on the distribution and function of specific channels and pumps in early embryogenesis. To provide a necessary basis for the molecular understanding of the role of ion flux in development, we surveyed the expression of ion channel and pump mRNAs, as well as other genes that help to regulate membrane potential. Analysis in two species, chick and Xenopus, shows that several ion channel and pump mRNAs are present in specific and dynamic expression patterns in early embryos, well before the appearance of neurons. Examination of the distribution of maternal mRNAs reveals complex spatiotemporal subcellular localization patterns of transcripts in early blastomeres in Xenopus. Taken together, these data are consistent with an important role for ion flux in early embryonic morphogenesis; this survey characterizes candidate genes and provides information on likely embryonic contexts for their function, setting the stage for functional studies of the morphogenetic roles of ion transport. © 2002 Wiley‐Liss, Inc.
Multiple maternal influences on dorsal–ventral fate of Xenopus animal blastomeres
Authors: Pandur Petra D. , Sullivan Steven A. , Moody Sally A. 
Published: December 2002

AbstractMolecular asymmetries in the animal–vegetal axis of the Xenopus oocyte are well known to regulate the formation of gametes and germ layers. Likewise, many transplantation and explant studies demonstrate that maternal dorsalizing activities are localized to the future dorsal side of the embryo after fertilization, but to date only a few of the molecules involved in this process have been shown to be asymmetrically distributed. In this report, we identify two new aspects of the maternal regulation of dorsal–ventral fate asymmetry in Xenopus blastomeres: cytoplasmic polyadenylation of dorsal maternal mRNAs and localized Wnt8b signaling. Previous studies demonstrated that there are maternal, dorsal axis‐inducing RNAs localized to dorsal animal blastomeres that become activated between the 8‐ and 16‐cell stage (Hainski and Moody [1992] Development 116:347–355; Hainski and Moody [1996] Dev. Genet. 19:210–221). We report herein that the activation of these axis‐inducing dorsal mRNAs is regulated by cytoplasmic polyadenylation. We also show that maternal wnt8b mRNA is concentrated in ventral animal blastomeres. These ventral cells and exogenous Wnt8b both inhibit the dorsal fate of neighboring blastomeres in culture, indicating that a maternal Wnt signal also contributes to segregating dorsal and ventral fates. © 2002 Wiley‐Liss, Inc.
Rethinking axial patterning in amphibians
Authors: Lane Mary Constance , Sheets Michael D. 
Published: December 2002

AbstractRecent revisions in the Xenopus laevis fate map led to the designation of the rostral/caudal axis and reassignment of the dorsal/ventral axis (Lane and Smith [1999] Development 126:423–434; Lane and Sheets [2000] Dev. Biol. 225:37–58). It is unprecedented to reassign primary embryonic axes after many years of research in a model system. In this review, we use insights about vertebrate development from anatomy and comparative embryology, as well as knowledge about gastrulation in frogs, to reexamine several traditional amphibian fate maps. We show that four extant maps contain information on the missing rostral/caudal axis. These maps support the revised map as well as the designation of the rostral/caudal axis and reassignment of the dorsal/ventral axes. To illustrate why it is important for researchers to use the revised map and nomenclature when thinking about frog and fish embryos, we present an example of alternative interpretations of “dorsalized” zebrafish mutations. © 2002 Wiley‐Liss, Inc.
Zygotic control of maternal cyclin A1 translation and mRNA stability
Authors: Audic Yann , Garbrecht Mark , Fritz Brian , Sheets Michael D. , Hartley Rebecca S. 
Published: December 2002

AbstractCyclin mRNAs are unstable in the adult cell cycle yet are stable during the first 12 cell divisions in Xenopus laevis. We recently reported that cyclin A1 and B2 maternal mRNAs are deadenylated upon completion of the 12th division (Audic et al. [2001] Mol. Cell Biol. 21:1662–1671). Deadenylation is mediated by the 3′ untranslated region (UTR) of the mRNA and precedes the terminal disappearance of the cyclin proteins, with both processes requiring zygotic transcription. The purpose of the current study was (1) to ask whether deadenylation leads to translational repression and/or destabilization of endogenous cyclin A1 and B2 mRNAs, and (2) to further characterize the regulatory sequences required. We show that zygote‐driven deadenylation leads to translational repression and mRNA destabilization. A 99‐nucleotide region of the 3′UTR of the cyclin A1 mRNA mediates both deadenylation and destabilization. Surprisingly, two AU‐rich consensus elements within this region are dispensable for this activity. These results suggest that zygote‐dependent deadenylation, translational repression, and mRNA destabilization by means of novel 3′UTR elements contribute to the disappearance of maternal cyclins. They also suggest that translational control of cyclins may play a role in the transition to the adult cell cycle. These data concur with previous studies in Drosophila showing that zygote‐mediated degradation of maternal cdc25 mRNA may be a general mechanism whereby transition to the adult cell cycle proceeds. © 2002 Wiley‐Liss, Inc.
Efficient principal component analysis for multivariate 3D voxel‐based mapping of brain functional imaging data sets as applied to FDG‐PET and normal aging
Authors: Zuendorf Gerhard , Kerrouche Nacer , Herholz Karl , Baron Jean‐Claude 
Published: December 2002

AbstractPrincipal component analysis (PCA) is a well‐known technique for reduction of dimensionality of functional imaging data. PCA can be looked at as the projection of the original images onto a new orthogonal coordinate system with lower dimensions. The new axes explain the variance in the images in decreasing order of importance, showing correlations between brain regions. We used an efficient, stable and analytical method to work out the PCA of Positron Emission Tomography (PET) images of 74 normal subjects using [18F]fluoro‐2‐deoxy‐D‐glucose (FDG) as a tracer. Principal components (PCs) and their relation to age effects were investigated. Correlations between the projections of the images on the new axes and the age of the subjects were carried out. The first two PCs could be identified as being the only PCs significantly correlated to age. The first principal component, which explained 10% of the data set variance, was reduced only in subjects of age 55 or older and was related to loss of signal in and adjacent to ventricles and basal cisterns, reflecting expected age‐related brain atrophy with enlarging CSF spaces. The second principal component, which accounted for 8% of the total variance, had high loadings from prefrontal, posterior parietal and posterior cingulate cortices and showed the strongest correlation with age (r = −0.56), entirely consistent with previously documented age‐related declines in brain glucose utilization. Thus, our method showed that the effect of aging on brain metabolism has at least two independent dimensions. This method should have widespread applications in multivariate analysis of brain functional images. Hum. Brain Mapping 18:13–21, 2003. © 2002 Wiley‐Liss, Inc.
Investigating the generators of the scalp recorded visuo‐verbal P300 using cortically constrained source localization
Authors: Moores Kathryn A. , Clark C. Richard , Hadfield Jo L. M. , Brown Greg C. , Taylor D. James , Fitzgibbon Sean P. , Lewis Andrew C. , Weber Darren L. , Greenblatt Richard 
Published: December 2002

AbstractConsiderable ambiguity exists about the generators of the scalp recorded P300, despite a vast body of research employing a diverse range of methodologies. Previous investigations employing source localization techniques have been limited largely to equivalent current dipole models, with most studies identifying medial temporal and/or hippocampal sources, but providing little information about the contribution of other cortical regions to the generation of the scalp recorded P3. Event‐related potentials (ERPs) were recorded from 5 subjects using a 124‐channel sensor array during the performance of a visuo‐verbal Oddball task. Cortically constrained, MRI‐guided boundary element modeling was used to identify the cortical generators of this target P3 in individual subjects. Cortical generators of the P3 were localized principally to the intraparietal sulcus (IPS) and surrounding superior parietal lobes (SPL) bilaterally in all subjects, though with some variability across subjects. Two subjects also showed activity in the lingual/inferior occipital gyrus and mid‐fusiform gyrus. A group cortical surface was calculated by non‐linear warping of each subject's segmented cortex followed by averaging and creation of a group mesh. Source activity identified across the group reflected the individual subject activations in the IPS and SPL bilaterally and in the lingual/inferior occipital gyrus primarily on the left. Activation of IPS and SPL is interpreted to reflect the role of this region in working memory and related attention processes and visuo‐motor integration. The activity in left lingual/inferior occipital gyrus is taken to reflect activation of regions associated with modality‐specific analysis of visual word forms. Hum. Brain Mapping 18:53–77, 2002. © 2002 Wiley‐Liss, Inc.
QALY‐maximisation and public preferences: results from a general population survey
Authors: Bryan Stirling , Roberts Tracy , Heginbotham Chris , McCallum Alison 
Published: December 2002

AbstractThe appropriate criteria that should be used in setting priorities in a publicly funded health care system remain open to debate. From a health economics perspective, quality‐adjusted life years (QALYs) are increasingly portrayed as a measure of societal value and the criterion of QALY maximisation is then advocated. This paper reports a study that investigated the extent to which some of the assumptions underlying the QALY maximisation approach, notably constant marginal societal value for increases in the size of health programmes, the level of risk, and the level of benefit are supported by members of the public. A general population interview‐based survey was conducted. The survey design employed conjoint methods. In general, the public preference data from this study, in themselves, are not much at odds with the core proportionality assumptions concerning societal value in the QALY maximisation model assumptions. The data are, however, at odds with reports from various previous studies. Copyright © 2002 John Wiley & Sons, Ltd.
The subjective costs of health losses due to chronic diseases. An alternative model for monetary appraisal
Authors: Ferrer‐i‐Carbonell Ada , van Praag Bernard M.S. 
Published: December 2002

AbstractThis paper proposes a method to evaluate health losses or gains by looking at the impact on well‐being of a change in health status. The paper presents estimates of the equivalent income change that would be necessary to change general satisfaction with life to the same extent as a change in health satisfaction would do. In other words, the income equivalent of health satisfaction changes is estimated. Next, this health satisfaction changes are linked to specific diseases in order to estimate the income equivalent for these diseases. This method uses answers to well‐being and health satisfaction questions as posed in a large German data set, distinguishing between workers and non‐workers and between East and West Germans. It is found, for instance, that for West‐German workers hearing impediments are on average equivalent to an income reduction of about 20%, and that heart or blood difficulties are for the same group equivalent to a 47% income reduction. Copyright © 2002 John Wiley & Sons, Ltd.
The importance of being first: evidence from Canadian generic pharmaceuticals
Authors: Hollis Aidan 
Published: December 2002

AbstractThis paper uses pooled cross‐section data on Canadian ethical drug sales to examine the effect of entry timing on sales of generic drugs. The data is for all drugs for which the first generic competitor entered during the years 1994–1997. It is found that the first generic entrant has a lasting competitive advantage: being first into the market appears to lead to an increase of around 30% in market share (among generics) over a period of at least 4 years. This finding has considerable implications for the current policy of allowing brandname drug companies to issue pseudo‐generic equivalents as a preemptive strike against true generic competitors. Copyright © 2002 John Wiley & Sons, Ltd.
Efficacy of citalopram and moclobemide in patients with social phobia: some preliminary findings
Authors: Atmaca Murad , Kuloglu Murat , Tezcan Ertan , Unal Ahmet 
Published: December 2002

AbstractThe efficacy of irreversible and reversible monoamine oxidase inhibitors (MAOIs) in the treatment of social phobia (SP) is well established. Recently, selective serotonin reuptake inhibitors (SSRIs) have been used more frequently. In the present study, the efficacy and side‐effect profile of citalopram, an SSRI, and moclobemide, the only MAOI used in Turkey, were compared. The 71 patients diagnosed with SP according to DSM‐III‐R were randomly assigned to two subgroups; citalopram (n = 36) or moclobemide (n = 35). The study was an 8‐week, randomized, open‐label, rater‐blinded, parallel‐group trial. All patients were assessed by Hamilton anxiety rating (HAM‐A), Liebowitz social anxiety (LSAS), clinical global impression‐severity of illness (CGI‐SI) and clinical global impression‐improvement (CGI‐I) scales. There was a similar percentage of responders (citalopram 75%, n = 27 and moclobemide 74.3%, n = 26), with a >50% or greater reduction in LSAS total score and ratings of ‘very much’ or ‘much improved’ on the CGI‐I. None of the patients withdrew from the study. The results of the present study suggest that citalopram has shown promising results in patients with SP. Copyright © 2002 John Wiley & Sons, Ltd.
Hydrodynamic modelling for groundwater flow through permeable reactive barriers
Authors: Das Diganta Bhusan 
Published: December 2002

AbstractHydrodynamic modelling for analysis of groundwater flow through permeable reactive barriers (PRBs) is addressed in this paper. Permeable reactive barriers constitute an emerging technology for in situ remediation of groundwater contamination and have many advantages over the traditional ex situ treatment methods. The transport domains during groundwater flow through PRBs often may involve free‐flow or non‐porous sections. To model the fluid mobility efficiently in such situations, the free and porous flow zones (PRBs) must be studied in conjunction with each other. The present paper is devoted to the analysis of groundwater flow through combined free flow domains and PRBs. The free‐flow regime is modelled using the Navier–Stokes equations whereas the permeable barriers are simulated by either the Darcy or the Brinkman equation. In order to couple the governing equations of motions, well‐posed mathematical formulations of matching boundary conditions are prescribed at the interface between the free‐groundwater‐flow zones and the permeable barriers. Combination of the Navier–Stokes equations with the Brinkman equation is more straightforward owing to their analogous forms. However, the Navier–Stokes and Darcy equations are incompatible mathematically and cannot be linked directly. The problem is resolved in this paper by invoking validated hydrodynamical expressions for describing the flow behaviour at the interfaces between free‐flow and porous zones. Three schemes for the analyses of fluid flow in combined domains are applied to the case of groundwater flow through permeable reactive barriers and different model results are compared. Copyright © 2002 John Wiley & Sons, Ltd.
Accuracy of kinematic wave and diffusion wave for spatial‐varying rainfall excess over a plane
Authors: Moramarco T. , Singh V. P. 
Published: December 2002

AbstractThe kinematic‐wave and diffusive‐wave approximations were investigated for unsteady overland flow resulting from spatially varying rainfall excess. Three types of boundary conditions were adopted: zero flow at the upstream end, and critical flow and zero depth‐gradient at the downstream end. Errors were derived by comparing the dimensionless profiles of the flow depth over the plane with those computed from the dynamic‐wave solution. It was found that the mean errors for both the approximations were independent of the type of rainfall excess distribution for KF02 > 5, where K is the kinematic‐wave number and F0 is the Froude number. Therefore, the regions (KF02, F0) where the kinematic‐wave and diffusive‐wave solutions would be fairly accurate and for any distribution of spatially varying rainfall, were characterized. The kinematic‐wave approximation was reasonably accurate, with a mean error of less than 5% and for the critical depth at the downstream end, for KF02 ≥ 20 with F0 ≤ 1; if the rainfall excess was concentrated in a portion of the plane, the field where the kinematic‐wave solution was found accurate, it was more limited and characterized for KF02 > 35 with F0 ≤ 1. The diffusive‐wave solution was in good agreement with the dynamic‐wave solution with a mean error of less than 5%, in the flow depth, for KF02 ≥ 15 with F0 ≤ 1; for rainfall excess concentrated in a portion of the plane, the accuracy of the diffusion wave solution was in a region more restricted and defined for KF02 ≥ 30 with F0 ≤ 1. For zero‐depth gradient at the downstream end, the accuracy field of the kinematic‐wave was found to be greater and characterized for KF02 > 10 with F0 ≤ 1; for rainfall excess concentrated in a portion of the plane, the region was smaller and defined for KF02 > 15 with F0 ≤ 1. The diffusive‐wave solution was found accurate in the region defined for KF02 > 7·5, whereas for rainfall excess concentrated in a portion of the plane, the field of accuracy was for KF02 > 12·5 with F0 ≤ 1. The lower limits of the regions, defined on KF02, can be considered generally valid for both approximations, but for F0 < 1 smaller lower limits were also characterized. Finally, the accuracy of these approximations was influenced significantly by the downstream boundary condition. Copyright © 2002 John Wiley & Sons, Ltd.
Effect of the duration and direction of storm movement on planar flow with full and partial areal coverage
Authors: Singh Vijay P. 
Published: December 2002

AbstractUsing kinematic wave equations, analytical solutions are derived for flow resulting from storms moving either up or down the plane and covering it fully or partially. By comparing the flow resulting from a moving storm with that from a stationary storm of the same duration and areal coverage, the influence of storm duration, direction and areal coverage is investigated. It is found that the direction, duration and areal coverage of storm movement have a pronounced effect on the discharge hydrograph. The runoff hydrographs resulting from storms moving downstream are quite different from those from storms moving upstream. Likewise, the areal coverage of the storm has a pronounced effect on the runoff hydrograph. Copyright © 2002 John Wiley & Sons, Ltd.
Apoptotic, but not necrotic, tumor cell vaccines induce a potent immune response in vivo
Authors: Scheffer Stephan R. , Nave Heike , Korangy Firouzeh , Schlote Karola , Pabst Reinhard , Jaffee Elizabeth M. , Manns Michael P. , Greten Tim F. 
Published: December 2002

AbstractProphylactic tumor vaccination against subsequent tumor challenge depends on effective cross‐priming in vivo. Professional APCs process tumor antigens from whole tumor cells and present them to CD4+ and CD8+ T cells. Data suggest that dendritic cells process antigens more efficiently from necrotic cells than from apoptotic cells in vitro. We compared the effect of apoptosis vs. necrosis in vivo using different tumor models (CT26, RENCA, B16 and CT26‐HA). Apoptosis was induced by γ‐irradiation prior to injection and verified in vivo. Apoptotic CT26‐HA, CT26‐wt or RENCA prevented tumor outgrowth in 100%, 75% and 100%, respectively, of mice for more than 30 days after challenge. In contrast, injection of necrotic tumor cells led to protection of no more than 0–30%. Prolonged tumor‐free survival was also observed in mice after vaccination with irradiated B16 cells. In vivo protection experiments correlated very well with in vitro cytotoxicity assays. Immunohistochemical analysis of the vaccine site showed a strong CD4+ and CD8+ T‐cell response after injection of apoptotic cells, which was accompanied by the presence of dendritic cells. In contrast, necrotic cell vaccines attracted a strong local macrophage response. Our data clearly demonstrate that only apoptotic tumor cell vaccines induce a potent antitumor immune response. © 2002 Wiley‐Liss, Inc.
Induction of matrix metalloproteinase gene transcription by nitric oxide and mechanisms of MMP‐1 gene induction in human melanoma cell lines
Authors: Ishii Yoshiyuki , Ogura Tsutomu , Tatemichi Masayuki , Fujisawa Hiroshi , Otsuka Fujio , Esumi Hiroyasu 
Published: December 2002

AbstractExpression of 12 matrix metalloproteinases (MMPs) after exposure of human melanoma cell lines C32TG and Mewo to nitric oxide (NO) was investigated by the reverse transcription‐polymerase chain reaction. Expression of the mRNA of MMP‐1, ‐3, ‐10 and ‐13 in C32TG cells was transcriptionally enhanced in a dose‐dependent manner by exposure to an NO donor, S‐nitroso‐N‐acetyl‐DL‐penicillamine (SNAP) and mRNA expression of MMP‐1 and ‐10 was similarly enhanced in Mewo cells. Exposure of C32TG cells to NO increased the MMP‐1 protein concentration in the culture medium. Testing with the luciferase gene fused to the 1.5 Kbp 5′‐flanking region of the human MMP‐1 gene showed that exposure to NO upregulated MMP‐1 promoter activity in C32TG cells. Endogenous NO production after introduction of inducible NO synthase cDNA also enhanced MMP‐1 promoter activity in C32TG cells. Deletion and mutational analysis identified a critical AP‐1 binding site required for NO regulation of MMP‐1. A neighboring Ets motif from the AP‐1 site in the promoter region acted as an accessory to enhance MMP‐1 expression. Electromobility shift analysis using the AP‐1 binding site showed that NO enhanced the AP‐1 binding ability of nuclear factors in C32TG cells. PD98059, a selective MEK inhibitor and SB202190, a p38 MAPK inhibitor, attenuated the MMP‐1 mRNA expression enhanced by NO. Thus, MMP‐1 was transcriptionally enhanced by NO via MAPK (ERK and p38) pathways. The results of our study suggest that the increased expression of MMPs in response to NO may be associated with tumor progression under inflammation. © 2002 Wiley‐Liss, Inc.