bluuebunny/crossref_metadata_2025_split huggingface dataset:
Why do acute myocardial infarction patients not call an ambulance? An interview with patients presenting to hospital with acute myocardial infarction symptoms
Authors: Lozzi L. , Carstensen S. , Rasmussen H. , Nelson G. 
Published: October 2005

Abstract Background: Studies from overseas indicate that patients with acute myocardial infarction (AMI) symptoms often fail to use the emergency services as recommended, thereby depriving themselves from life‐saving treatment in case of cardiac arrest and delaying the time to myocardial reperfusion in the presence of a coronary occlusion.Aims: To compare patients brought in by ambulance to those not brought in by ambulance and to question why some patients do not use the emergency services when presenting to hospital with AMI symptoms.Methods: Prospective interview and follow up of consecutive patients presenting with AMI symptoms to the emergency department of a tertiary hospital in a metropolitan area within a 1‐month period.Results: Of the 215 patients presenting to the emergency department, 113 (53%) arrived by private transportation. Sixty (53%) of these felt their symptoms did not warrant calling the ambulance, 17 (15%) had first consulted their general practitioner. The private transport group accounted for 28% of documented AMI.Conclusions: A large proportion of patients with AMI symptoms refrain from calling the emergency services because they do not consider themselves critically ill. Education programmes appear to be warranted because more appropriate use of emergency services will save lives. (Intern Med J 2005; 35: 668–671)
Inputs to nucleus pontis caudalis from adjacent trigeminal areas
Authors: Dal Bo G. , Lund J. P. , Verdier D. , Kolta A. 
Published: October 2005

AbstractRecent studies suggest that the nucleus pontis caudalis (nPontc) plays a role in patterning mastication through interactions with the adjacent lateral tegmentum. In this study, we used in vitro intracellular recording and staining to describe the basic membrane properties and morphology of nPontc neurones and to further explore interactions with adjacent structures, using coronal sections of the brainstem of 78 rats, aged 9–28 days. Neurones were large, with dendrites that spread in all directions, and about 64% fired tonically even in the absence of synaptic inputs. Tonic neurones were predominant in the centre of the nucleus. Electrical stimulation of all regions of the nPontc produced mixed excitatory and inhibitory effects on interneurones of lateral tegmental nuclei. Focal inactivation of the dorsal nPontc with injections of tetrodotoxin also had mixed effects on the spontaneous firing of both interneurones and motoneurones but similar injections in the ventral nPontc produced mostly increases of firing. Sixty‐five percent of nPontc neurones received synaptic inputs from the lateral tegmental areas and most of these (68%) were excitatory and mediated by glutamatergic receptors. Inhibitory postsynaptic potentials were mediated by GABAA or glycinergic receptors. Although most responses occurred at relatively long latencies (> 2 ms), they could follow relatively high‐frequency stimulation (> 50 Hz). Excitatory and inhibitory connections between ipsi‐ and contralateral nPontc neurones were also documented, which could contribute to bilateral coordination of jaw movements. This study provides evidence that the nPontc exerts both tonic and phasic influences on the premotor components of the masticatory central pattern generator.
Increased generation of granule cells in adult Bcl‐2‐overexpressing mice: a role for cell death during continued hippocampal neurogenesis
Authors: Kuhn H. Georg , Biebl Manfred , Wilhelm Daniel , Li Mingwei , Friedlander Robert M. , Winkler Jürgen 
Published: October 2005

AbstractProgrammed cell death is an important mechanism during brain development in order to control neuronal cell numbers and to correctly form neuronal circuitries. Programmed cell death is also present in neurogenic regions of the adult brain, and a significant portion of the adult‐born cells is eliminated during the first months of maturation. We here address the question whether overexpression of the anti‐apoptotic protein Bcl‐2 would improve the survival of neural progenitor cells and, as a consequence, increase neurogenesis in the adult hippocampus. Transgenic animals, which express human Bcl‐2 under the neuron‐specific enolase promoter (NSE‐huBcl‐2), show a significant reduction of apoptotic cells in the hippocampal granule cell layer to about half of the wild‐type level. These apoptotic cells are almost exclusively found in the zone of hippocampal progenitor activity and frequently co‐label with the neuronal progenitor marker doublecortin (DCX). The rate of adult neurogenesis is doubled in the dentate gyrus of Bcl‐2‐overexpressing mice as demonstrated by quantification of progenitor cells using DCX and new neurons using bromodeoxyuridine (BrdU)/neuronal nuclei antigen (NeuN) double‐labelling. The effect of Bcl‐2 is limited to the late phase of progenitor maturation, as proliferation and early‐phase progenitor cells were not affected. The increased level of neurogenesis leads to a significantly higher total number of granule cells in the dentate gyrus. These results underline the importance of developmental cell death during neurogenesis in the adult brain.
The SDF‐1/CXCR4 pathway and the development of the cerebellar system
Authors: Vilz Tim O. , Moepps Barbara , Engele Jürgen , Molly Sabine , Littman Dan R. , Schilling Karl 
Published: October 2005

AbstractMice deficient for the chemokine receptor CXCR4 show premature translocation of granule cell neuroblasts from their germinal zone into the nascent cerebellum [Y.‐R. Zuo et al. (1998)Nature, 393, 595–599]. Here, we used CXCR4‐null mice to analyse the early development of cerebellar cortical inhibitory interneurons and pontine neurons which, in the adult, are synaptically integrated with granule cells. Cortical inhibitory interneuronal precursors normally invade the cerebellar anlage of CXCR4‐deficient mice, but their dispersal is impeded by dislocated foci of proliferating granule cells, from which they are excluded. This is reminiscent of the strict exclusion of inhibitory interneuronal precursors from the superficial external granule cell layer. As inhibitory interneuronal precursors readily mingle with post‐mitotic granule cells both in wild‐type and CXCR4‐null mice, these findings indicate that the developmentally regulated interactions between granule and inhibitory interneuronal precursors are independent of SDF‐1/CXCR4 signalling. In contrast, the transit of pontine neurons from the rhombic lip through the anterior extramural stream to the basilar pons is disrupted in CXCR4‐deficient animals. Migrating pontine neurons express CXCR4, and in CXCR4‐null animals these cells are found displaced deep into the brainstem. Consequently, nascent pontine nuclei in CXCR4‐deficient animals are hypoplastic. Moreover, they fail to express plexin D1, suggesting that SDF‐1/CXCR4 signalling may also impinge on axon guidance critical to the orderly formation of granule cell mossy fibre afferents.
Neurite guidance by the FnC repeat of human tenascin‐C: neurite attraction vs. neurite retention
Authors: Liu Hsing‐Yin , Nur‐E‐Kamal Alam , Schachner Melitta , Meiners Sally 
Published: October 2005

AbstractThe alternatively spliced fibronectin type‐III repeat C of human tenascin‐C (fnC) provides directional cues to elongating neurites in vitro. When given a choice at an interface with poly l‐lysine (PLL), rat cerebellar granule neurites preferentially crossed onto fnC (defined herein as neurite attraction) whereas neurites originating on fnC preferentially remained on fnC (defined as neurite retention). Guidance motifs were further refined using synthetic peptides spanning the sequence of fnC. We found that a peptide with amino acid sequence DINPYGFTVSWMASE was sufficient to attract and retain neurites. Peptides with alterations in NPYG facilitated neurite retention but not attraction and, conversely, molecules with alterations in ASE facilitated neurite attraction but not retention. Hence neurite attraction and neurite retention mediated by fnC are separable events that can be independently regulated. This property may prove valuable for the strategic design of peptide reagents for use in strategies to facilitate directed axonal regrowth following CNS injury.
Histamine‐immunoreactive neurons in the mouse and rat suprachiasmatic nucleus
Authors: Michelsen Kimmo A. , Lozada Adrian , Kaslin Jan , Karlstedt Kaj , Kukko‐Lukjanov Tiina‐Kaisa , Holopainen Irma , Ohtsu Hiroshi , Panula Pertti 
Published: October 2005

AbstractAmong the well‐established roles of the neurotransmitter histamine (HA) is that as a regulator of the sleep–wake cycle, which early gained HA a reputation as a ‘waking substance’. The tuberomammillary nucleus (TMN) of the posterior hypothalamus, which contains the sole source of neuronal HA in the brain, is reciprocally connected to the suprachiasmatic nucleus (SCN) which, in turn, is best known as the pacemaker of circadian rhythms in mammals. We report HA‐immunoreactive (‐ir) neurons in the mouse and rat SCN that neither display immunoreactivity (‐iry) for the HA‐synthesizing enzyme histidine decarboxylase (HDC) nor contain HDC mRNA. Further, HA‐iry was absent in the SCN of HDC knockout mice, but present in appropriate control animals, indicating that the observed HA‐iry is HDC dependent. Experiments with hypothalamic slice cultures and i.c.v. injection of HA suggest that HA in the SCN neurons originates in the TMN and is transported from the TMN along histaminergic fibres known to innervate the SCN. These results could indicate the existence of a hitherto unknown uptake mechanism for HA into neurons. Through HA uptake and, putatively, re‐release of the captured HA, these neurons could participate in the HA‐mediated effects on the circadian system in concert with direct histaminergic inputs from the TMN to the SCN. The innervation of the SCN by several neurotransmitter systems could provide a way for other systems to affect the HA‐containing neuronal cell bodies in the SCN.
Contributions of protein phosphatases PP1, PP2A, PP2B and PP5 to the regulation of tau phosphorylation
Authors: Liu Fei , Grundke‐Iqbal Inge , Iqbal Khalid , Gong Cheng‐Xin 
Published: October 2005

AbstractAbnormal hyperphosphorylation of tau is believed to lead to neurofibrillary degeneration in Alzheimer's disease (AD) and other tauopathies. Recent studies have shown that protein phosphatases (PPs) PP1, PP2A, PP2B and PP5 dephosphorylate tau in vitro, but the exact role of each of these phosphatases in the regulation of site‐specific phosphorylation of tau in the human brain was unknown. Hence, we investigated the contributions of these PPs to the regulation of tau phosphorylation quantitatively. We found that these four phosphatases all dephosphorylated tau at Ser199, Ser202, Thr205, Thr212, Ser214, Ser235, Ser262, Ser396, Ser404 and Ser409, but with different efficiencies toward different sites. The Km values of tau dephosphorylation catalysed by PP1, PP2A and PP5 were 8–12 µm, similar to the intraneuronal tau concentration of human brain, whereas the Km of PP2B was fivefold higher. PP2A, PP1, PP5 and PP2B accounted for ∼ 71%, ∼ 11%, ∼ 10% and ∼ 7%, respectively, of the total tau phosphatase activity of human brain. The total phosphatase activity and the activities of PP2A and PP5 toward tau were significantly decreased, whereas that of PP2B was increased in AD brain. PP2A activity negatively correlated to the level of tau phosphorylation at the most phosphorylation sites in human brains. Our findings indicate that PP2A is the major tau phosphatase that regulates its phosphorylation at multiple sites in human brain. The abnormal hyperphosphorylation of tau is partially due to a downregulation of PP2A activity in AD brain.
Ultrastructural evidence for a pre‐ and postsynaptic localization of full‐length trkB receptors in substantia gelatinosa (lamina II) of rat and mouse spinal cord
Authors: Salio Chiara , Lossi Laura , Ferrini Francesco , Merighi Adalberto 
Published: October 2005

AbstractBrain‐derived neurotrophic factor (BDNF) exerts its trophic effects by acting on the high‐affinity specific receptor trkB. BDNF also modulates synaptic transmission in several areas of the CNS, including the spinal cord dorsal horn, where it acts as a pain modulator by yet incompletely understood mechanisms. Spinal neurons are the main source of trkB in lamina II (substantia gelatinosa). Expression of this receptor in dorsal root ganglion (DRG) cells has been a matter of debate, whereas a subpopulation of DRG neurons bears trkA receptors and contains BDNF. By the use of two different trkB antibodies we observed that 7.7% and 10.8% of DRG neurons co‐expressed BDNF + trkB but not trkA, respectively, in rat and mouse. Ultrastructurally, full‐length trkB (fl‐trkB) receptors were present at somato‐dendritic membranes of lamina II neurons (rat: 66.8%; mouse: 73.8%) and at axon terminals (rat: 33.2%; mouse: 26.2%). In both species, about 90% of these terminals were identified as primary afferent fibres (PAFs) considering their morphology and/or neuropeptide content. All fl‐trkB‐immunopositive C boutons in type Ib glomeruli were immunoreactive for BDNF and, at individual glomeruli and axo‐dendritic synapses, fl‐trkB receptors were located in a mutually exclusive fashion at pre‐ or postsynaptic membranes. Thus, only a small fraction of fl‐trkB‐immunoreactive dendrites were postsynaptic to BDNF‐immunopositive PAFs. This is the first ultrastructural description of fl‐trkB localization at synapses between first‐ and second‐order sensory neurons in lamina II, and suggests that BDNF may be released by fl‐trkB‐immunopositive PAFs to modulate nociceptive input in this lamina of dorsal horn.
Long‐range oscillatory Ca2+ waves in rat spinal dorsal horn
Authors: Ruscheweyh Ruth , Sandkühler Jürgen 
Published: October 2005

AbstractSynchronous activity of large populations of neurons shapes neuronal networks during development. However, re‐emergence of such activity at later stages of development could severely disrupt the orderly processing of sensory information, e.g. in the spinal dorsal horn. We used Ca2+ imaging in spinal cord slices of neonatal and young rats to assess under which conditions synchronous activity occurs in dorsal horn. No spontaneous synchronous Ca2+ transients were detected. However, increasing neuronal excitability by application of 4‐aminopyridine after pretreatment of the slice with blockers of (RS)‐alpha‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid (AMPA)/kainate, γ‐aminobutyric acid (GABA)A and glycine receptors evoked repetitive Ca2+ waves in dorsal horn. These waves spread mediolaterally with a speed of 1.0 ± 0.1 mm/s and affected virtually every dorsal horn neuron. The Ca2+ waves were associated with large depolarizing shifts of the membrane potential of participating neurons and were most likely synaptically mediated because they were abolished by blockade of action potentials or N‐methyl‐d‐aspartate (NMDA) receptors. They were most pronounced in the superficial dorsal horn and absent from the ventral horn. A significant proportion of the Ca2+ waves spread to the contralateral dorsal horn. This seemed to be enabled by disinhibition as primary afferent‐induced dorsal horn excitation crossed the midline only when GABAA and glycine receptors were blocked. Interestingly, the Ca2+ waves occurred under conditions where AMPA/kainate receptors were blocked. Thus, superficial dorsal horn NMDA receptors are able to sustain synchronous neuronal excitation in the absence of functional AMPA/kainate receptors.
Putaminal gray matter volume decrease in panic disorder: an optimized voxel‐based morphometry study
Authors: Yoo Hanik K. , Kim Minue J. , Kim Seog Ju , Sung Young Hoon , Sim Minyoung E. , Lee Yujin S. , Song Seong Yong , Kee Baik Seok , Lyoo In Kyoon 
Published: October 2005

AbstractOur study aimed to identify gray matter volume differences between panic disorder patients and healthy volunteers using optimized voxel‐based morphometry. Gray matter volume was compared between 18 panic subjects and 18 healthy volunteers. Panic disorder severity scale (PDSS) and Zung self‐rating anxiety scale (Z‐SAS) were administered. Gray matter volumes of bilateral putamen were decreased in panic subjects relative to healthy comparison subjects (corrected P < 0.05). Decreased gray matter volume was also observed in the right precuneus, right inferior temporal gyrus, right inferior frontal gyrus, left superior temporal gyrus, and left superior frontal gyrus at a less conservative level of significance. PDSS score negatively correlated with gray matter volume in the left putamen, right putamen, right inferior frontal gyrus, and left superior frontal gyrus in panic subjects. The duration of illness negatively correlated with left putaminal gray matter volume. There was also a negative correlation between gray matter volume in right putamen and Z‐SAS score in panic subjects. The current study reports a putaminal gray matter volume decrease in panic subjects, which may be related to the clinical severity of panic disorder.
The fate of neural progenitor cells expressing astrocytic and radial glial markers in the postnatal rat dentate gyrus
Authors: Namba Takashi , Mochizuki Hideki , Onodera Masafumi , Mizuno Yoshikuni , Namiki Hideo , Seki Tatsunori 
Published: October 2005

AbstractIn the dentate gyrus neurons continue to be generated from late embryonic to adult stage. Recent extensive studies have unveiled several key aspects of the adult neurogenesis, but only few attempts have so far been made on the analysis of the early postnatal neurogenenesis, a transition state between the embryonic and adult neurogenesis. Here, we focus on the early postnatal neurogenesis and examine the nature and development of neural progenitor cells in Wistar rats. Immunohistochemistry for Ki67, a cell cycle marker, and 5‐bromo‐2‐deoxyuridine (BrdU) labelling show that cell proliferation occurs mainly in the hilus and partly in the subgranular zone. A majority of the proliferating cells express S100β and astrocyte‐specific glutamate transporter (GLAST) and the subpopulation are also positive for glial fibrillary acidic protein (GFAP) and nestin. Tracing with BrdU and our modified retrovirus vector carrying enhanced green fluorescent protein (GFP) indicate that a substantial population of the proliferating cells differentiate into proliferative neuroblasts and immature neurons in the hilus, which then migrate to the granule cell layer (66.8%), leaving a long axon‐like process behind in the hilus, and the others mainly become star‐shaped astrocytes (12.0%) and radial glia‐like cells (4.7%) in the subgranular zone. These results suggest that the progenitors of the granule cells expressing astrocytic and radial glial markers, proliferate and differentiate into neurons mainly in the hilus during the early postnatal period.
Formative research on an early stage of the systemic change process in a small school district
Authors: Joseph Roberto , Reigeluth Charles M. 
Published: October 2005

AbstractThis study utilised a qualitative research methodology known as formative research to improve the process guidelines that are described in the Guidance System for Transforming Education (GSTE). This study took place in a small (5447 students), partly urban and partly rural school district in Indiana. The researchers, also serving as change facilitators, investigated an early stage of the systemic change process as outlined in the GSTE. Specifically, the research focused on field‐testing and improving the process for assessing the district's readiness for change. It was found that this process could have been improved if the facilitators had had more guidance to help them develop the interview protocols.
Supporting change and scholarship through review of online resources in professional development settings
Authors: Ravitz Jason , Hoadley Christopher 
Published: October 2005

AbstractHow can we accelerate innovation and ensure effective dissemination of knowledge about online learning resources? This paper advocates strategies that systematically link online professional development with the research, development and diffusion cycle. The systemic approach we describe can accelerate knowledge advancement and help manage change by improving communication among teachers, trainers, developers and researchers. The examples that are provided are set within two funded projects in the United States that led to the development of two distinct but related strategies—the Online Site Evaluation Form for educators (a web‐based review form used in workshops) and a six‐week online course on technology‐supported assessments. Both strategies make it easier to give feedback to developers and offer incentives to do so in ways that help teachers to learn about online resources individually and with colleagues. The examples are discussed with analysis of their strengths and weaknesses in supporting different modes of interaction. We highlight implications for instructional development, professional development, research and knowledge management in online communities.
Challenge 98: sustaining the work of a regional technology integration initiative
Authors: Billig Shelley H. , Sherry Lorraine , Havelock Bruce 
Published: October 2005

AbstractIn this article, we offer a research‐based theoretical framework for sustainability, describing the proven qualities of a project and the innovations that support its sustained existence over time. We then describe how a US Department of Education Technology Innovation Challenge grantee, working to promote technology integration in a socio‐economically disadvantaged region of the state of Texas, succeeded in creating a sustainable set of activities around its work to support educators’ uses of technology. We examine the factors that served to nurture and facilitate sustainability of the practices associated with technology integration to promote student achievement. We take the fact that it is not the project but rather the change in practice that is important.
Why we all want it to work: towards a culturally based model for technology and educational change
Authors: Kerr Stephen T. 
Published: October 2005

AbstractThis paper explores reasons why the use of technology in education may be so attractive to so many people. Two emerging perspectives—memetics, and the social history of technology—are explored, and a typology of technology‐as‐cultural‐tool is presented. Finally, implications of these ideas for educational change are considered.