bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differentiation of an auditory neuronal cell line suitable for cell transplantation
Authors: Nicholl A. J. , Kneebone A. , Davies D. , Cacciabue‐Rivolta D. I. , Rivolta M. N. , Coffey P. , Holley M. C. 
Published: July 2005

AbstractThe auditory neuroblast cell line US/VOT‐N33 (N33), which is conditionally immortal, was studied as an in vitro model for the differentiation of spiral ganglion neurons (SGNs) and as a candidate for cell transplantation in rodents. It expresses numerous molecular markers characteristic of auditory neuroblasts, including the transcription factors GATA3, NeuroD, Brn3a and Islet1, as well as the neuronal cytoskeletal protein β3‐tubulin. It displays active migratory behaviour in vitro and in vivo. In the presence of the fibroblast growth factors FGF1 or FGF2 it differentiates bipolar morphologies similar to those of native SGNs. In coculture with neonatal cochlear tissue it is repelled from epithelial surfaces but not from native SGNs, alongside which it extends parallel neuronal processes. When injected into the retina in vivo, EGFP‐labelled N33 cells were traced for 1–2 weeks and migrated rapidly within the subretinal space. Cells that found their way into the retinal ganglion cell layer extended multiple processes but did not express β3‐tubulin. The ability of N33 to migrate, to differentiate, to localize with native SGNs in vitro and to survive in vivo suggests that they provide an effective model for SGN differentiation and for cell transplantation into the ear.
The role of the dorsomedial striatum in instrumental conditioning
Authors: Yin Henry H. , Ostlund Sean B. , Knowlton Barbara J. , Balleine Bernard W. 
Published: July 2005

AbstractConsiderable evidence suggests that, in instrumental conditioning, rats learn the relationship between actions and their specific consequences or outcomes. The present study examined the role of the dorsomedial striatum (DMS) in this type of learning after excitotoxic lesions and reversible, muscimol‐induced inactivation. In three experiments, rats were first trained to press two levers for distinct outcomes, and then tested after training using a variety of behavioural assays that have been established to detect action‐outcome learning. In Experiment 1, pre‐training lesions of the posterior DMS abolished the sensitivity of rats' instrumental performance to both outcome devaluation and contingency degradation when tested in extinction, whereas lesions of the anterior DMS had no effect. In Experiment 2, both pre‐training and post‐training lesions of the posterior DMS were equally effective in reducing the sensitivity of performance both to devaluation and degradation treatments. In Experiment 3, the infusion of muscimol into the posterior DMS selectively abolished sensitivity of performance to devaluation and contingency degradation without impairing the ability of rats to discriminate either the instrumental actions performed or the identity of the earned outcomes. Taken together, these results suggest that the posterior region of the DMS is a crucial neural substrate for the acquisition and expression of action–outcome associations in instrumental conditioning.
Frequency‐dependent impairment of hippocampal LTP from NMDA receptors with reduced calcium permeability
Authors: Pawlak Verena , Jensen Vidar , Schupp Bettina J. , Kvello Ane , Hvalby Øivind , Seeburg Peter H. , Köhr Georg 
Published: July 2005

AbstractChanges in postsynaptic Ca2+ levels are essential for alterations in synaptic strength. At hippocampal CA3‐to‐CA1 synapses, the Ca2+ elevations required for LTP induction are typically mediated by NMDA receptor (NMDAR) channels but a contribution of NMDAR‐independent Ca2+ sources has been implicated. Here, we tested the sensitivity of different protocols modifying synaptic strength to reduced NMDAR‐mediated Ca2+ influx by employing mice genetically programmed to express in forebrain principal neurons an NR1 form that curtails Ca2+ permeability. Reduced NMDAR‐mediated Ca2+ influx did not facilitate synaptic depression in CA1 neurons of these genetically modified mice. However, we observed that LTP could not be induced by pairing low frequency synaptic stimulation (LFS pairing) with postsynaptic depolarization, a protocol that induced robust LTP in wild‐type mice. By contrast to LFS pairing, similar LTP levels were generated in both genotypes when postsynaptic depolarization was paired with high frequency synaptic stimulation (HFS). This indicates that the postsynaptic Ca2+ elevation also reached threshold during HFS in the mutant, probably due to summation of NMDAR‐mediated Ca2+ influx. However, only in wild‐type mice did repeated HFS further enhance LTP. All tested forms of LTP were blocked by the NMDAR antagonist D‐AP5. Collectively, our results indicate that only NMDAR‐dependent Ca2+ sources (NMDARs and Ca2+‐dependent Ca2+ release from intracellular stores) mediate LFS pairing‐evoked LTP. Moreover, LTP induced by the first HFS stimulus train required lower Ca2+ levels than the additional LTP obtained by repeated trains.
S‐cones do not contribute to the OFF‐midget pathway in the retina of the marmoset, Callithrix jacchus
Authors: Lee Sammy C. S. , Telkes Ildiko , Grünert Ulrike 
Published: July 2005

AbstractIt is well established that in primate retina both medium‐ and long‐wavelength‐sensitive cone types provide input to the midget‐parvocellular pathway. The question, however, whether short‐wavelength‐sensitive (S or ‘blue’) cones provide input to the OFF‐division of the midget‐parvocellular pathway is still controversial. In the present study, we investigated the connections of nearly 400 S‐cones with OFF‐midget bipolar cells in central and peripheral retina of a New World monkey, the marmoset. Horizontal sections or pieces of whole retinae were double‐labelled with an antiserum to S‐cone opsin to identify S‐cones and antibodies to the cell adhesion molecule CD15 to identify OFF‐midget bipolar cells. Peanut agglutinin coupled to a fluorescent tag was used to label the cone pedicles of all cone types. Peanut agglutinin was also used to distinguish S‐cones from the other cone types. The sections were analysed with deconvolution microscopy. We found that nearly all pedicles of medium‐ and long‐wavelength‐sensitive cones are located opposite distinct dendritic clusters formed by OFF‐midget bipolar cells. By contrast, the S‐cone pedicles are not located opposite dendritic clusters. Instead, S‐cones make sparse contacts with CD15‐labelled processes. Some of these processes protruded from OFF‐midget bipolar clusters, whereas others could be traced to a diffuse bipolar cell type. Thus, in the marmoset retina the midget‐parvocellular system does not carry a blue‐OFF signal.
How does transcranial DC stimulation of the primary motor cortex alter regional neuronal activity in the human brain?
Authors: Lang Nicolas , Siebner Hartwig R. , Ward Nick S. , Lee Lucy , Nitsche Michael A. , Paulus Walter , Rothwell John C. , Lemon Roger N. , Frackowiak Richard S. 
Published: July 2005

AbstractTranscranial direct current stimulation (tDCS) of the primary motor hand area (M1) can produce lasting polarity‐specific effects on corticospinal excitability and motor learning in humans. In 16 healthy volunteers, O positron emission tomography (PET) of regional cerebral blood flow (rCBF) at rest and during finger movements was used to map lasting changes in regional synaptic activity following 10 min of tDCS (± 1 mA). Bipolar tDCS was given through electrodes placed over the left M1 and right frontopolar cortex. Eight subjects received anodal or cathodal tDCS of the left M1, respectively. When compared to sham tDCS, anodal and cathodal tDCS induced widespread increases and decreases in rCBF in cortical and subcortical areas. These changes in rCBF were of the same magnitude as task‐related rCBF changes during finger movements and remained stable throughout the 50‐min period of PET scanning. Relative increases in rCBF after real tDCS compared to sham tDCS were found in the left M1, right frontal pole, right primary sensorimotor cortex and posterior brain regions irrespective of polarity. With the exception of some posterior and ventral areas, anodal tDCS increased rCBF in many cortical and subcortical regions compared to cathodal tDCS. Only the left dorsal premotor cortex demonstrated an increase in movement related activity after cathodal tDCS, however, modest compared with the relatively strong movement‐independent effects of tDCS. Otherwise, movement related activity was unaffected by tDCS. Our results indicate that tDCS is an effective means of provoking sustained and widespread changes in regional neuronal activity. The extensive spatial and temporal effects of tDCS need to be taken into account when tDCS is used to modify brain function.
Nociceptive spinal withdrawal reflexes but not spinal dorsal horn wide‐dynamic range neuron activities are specifically inhibited by halothane anaesthesia in spinalized rats
Authors: You Hao‐Jun , Colpaert Francis C. , Arendt‐Nielsen Lars 
Published: July 2005

AbstractThe aim of the present study was to investigate the spinal cord effects and sites of action of different inhaled concentrations (0.5–2%) of the anaesthetic, halothane. Simultaneous recordings were made of 3 Hz, suprathreshold (1.5 × T) electrically evoked spinal dorsal horn (DH) wide‐dynamic range (WDR) neuron responses and of single motor unit (SMU) electromyographic (EMG) responses underlying the spinal withdrawal reflex in spinalized Wistar rats. Compared with the baseline responses obtained with 0.5% halothane, the electrically evoked early responses of the DH WDR neurons as well as the SMUs were only depressed by the highest, 2% concentration of halothane. In contrast, 1.5% halothane markedly inhibited the late responses of the DH WDR neurons, whereas 1% halothane started to significantly depress the late responses of the SMUs. Likewise, wind‐up of the WDR neuron late responses was inhibited by 1.5–2% halothane, whereas 1–2% halothane significantly depressed wind‐up of the SMU EMG late responses. The inhibitory effects of 2% halothane on the early and the late responses of the DH WDR neurons, but not of the SMUs, were completely reversed by opioid µ‐receptor antagonist naloxone (0.04 mg/kg). However, no significant effects of naloxone were found on different responses of the DH WDR neurons as well as the SMUs at 0.5–1% halothane, suggesting that different concentrations of halothane may modulate different spinal receptors. We conclude that halothane at high concentrations (1.5–2%) seems to play a predominant inhibitory role via spinal multireceptors on ventral horn (VH) motor neurons, and less on DH sensory WDR neurons, of the spinal cord.
Roles of NMDA receptor NR2A and NR2B subtypes for long‐term depression in the anterior cingulate cortex
Authors: Toyoda Hiroki , Zhao Ming‐Gao , Zhuo Min 
Published: July 2005

AbstractThe anterior cingulate cortex (ACC) is thought to be important for the establishment, consolidation and retrieval of permanent memory. In many brain regions, including the hippocampus, it is suggested that long‐term potentiation (LTP) and long‐term depression (LTD), the cellular mechanisms for learning and memory, require the activation of glutamate N‐methyl‐d‐aspartate receptors (NMDARs). In the hippocampus, the NR2A subunit is believed to be involved in the induction of LTP, whereas the NR2B subunit contributes to the formation of LTD. However, LTD has been less well studied in the ACC as compared with the hippocampus and little is known about the role of NMDA subtype receptors in cingulate LTD. Here we show that LTD can be induced by the combination of presynaptic stimulation with postsynaptic depolarization (‘pairing training’) in adult mouse ACC neurons. This form of LTD is an NMDAR‐ and voltage‐dependent mechanism and a postsynaptic Ca2+ increase is required for the induction of LTD. Furthermore, our studies provide direct physiological evidence that both NR2A and NR2B subunits are involved in the induction of LTD in the ACC.
The Cost Effectiveness of the UK's Sovereign Debt Portfolio*
Authors: Coe Patrick J. , Hashem Pesaran M. , Vahey Shaun P. 
Published: July 2005

AbstractThis paper provides a recursive empirical analysis of the scope for cost minimization in public debt management when the debt manager faces a given short‐term interest rate dictated by monetary policy as well as risk and market impact constraints. It simulates the ‘real‐time’ interest costs of alternative portfolios for UK government debt between April 1985 and March 2000. These portfolios are constructed using forecasts of return spreads based on a recursive modelling procedure. While we find statistically significant evidence of predictability, the interest cost savings are quite small when portfolio shares are constrained to lie within historical bounds.
Monetary Frameworks and Institutional Constraints: UK Monetary Policy Reaction Functions, 1985–2003
Authors: Adam Christopher , Cobham David , Girardin Eric 
Published: July 2005

AbstractMonetary policy reaction functions are estimated for the UK over three periods – 1985–90, 1992–97 and 1997–2003 – in order to disentangle two effects: the switch from an emphasis on exchange rate stabilization to inflation targeting, and the introduction of instrument‐independence in 1997. The external factors considered include US as well as German interest rates, and this leads to the identification of ‘domestic’ and ‘international’ models of the reaction function. The results suggest that it is the changes in the institutional arrangements rather than those in the targeting regime which have been decisive in the development of policy in this period.
Prewhitening Bias in HAC Estimation*
Authors: Sul Donggyu , Phillips Peter C. B. , Choi Chi‐Young 
Published: July 2005

AbstractHeteroskedasticity and autocorrelation consistent (HAC) estimation commonly involves the use of prewhitening filters based on simple autoregressive models. In such applications, small sample bias in the estimation of autoregressive coefficients is transmitted to the recolouring filter, leading to HAC variance estimates that can be badly biased. The present paper provides an analysis of these issues using asymptotic expansions and simulations. The approach we recommend involves the use of recursive demeaning procedures that mitigate the effects of small‐sample autoregressive bias. Moreover, a commonly used restriction rule on the prewhitening estimates (that first‐order autoregressive coefficient estimates, or largest eigenvalues, >0.97 be replaced by 0.97) adversely interferes with the power of unit‐root and [Kwiatkowski, Phillips, Schmidt and Shin (1992)Journal of Econometrics, Vol. 54, pp. 159–178] (KPSS) tests. We provide a new boundary condition rule that improves the size and power properties of these tests. Some illustrations of the effects of these adjustments on the size and power of KPSS testing are given. Using prewhitened HAC estimates and the new boundary condition rule, the KPSS test is consistent, in contrast to KPSS testing that uses conventional prewhitened HAC estimates [Lee, J. S. (1996)Economics Letters, Vol. 51, pp. 131–137].
Programme Evaluation with Unobserved Heterogeneity and Selective Implementation: The Mexican PROGRESA Impact on Child Nutrition
Authors: Behrman Jere R. , Hoddinott John 
Published: July 2005

AbstractThis paper considers the impact of Programa de Educación, Salud y Alimentación (PROGRESA), a large Mexican rural anti‐poverty programme that had an evaluation sample in which overall treatment was randomly assigned to some communities but not others, on child nutrition. When we examine the impact of PROGRESA based on the presumption of randomized allocations, we find that PROGRESA had no or even a negative impact on child nutrition. However, not all children designated to receive nutritional supplements actually did so. Our preferred estimates – child fixed‐effects estimates that control for unobserved heterogeneity that is correlated with access to the supplement – indicate a significantly positive and fairly substantial programme effect of the nutritional supplements on children 12–36 months. They imply an increase of about a sixth in mean growth per year for these children and a lower probability of stunting. Effects are somewhat larger for children from poorer communities but whose mothers are functionally literate. The long‐term consequences of these improvements are non‐trivial; its impact working through adult height alone could result in a 2.9% increase in lifetime earnings.
Oral Lichen Planus in Childhood
Authors: Laeijendecker Ronald , Van Joost Theodoor , Tank Bhupendra , Oranje Arnold P. , Neumann H. A. Martino 
Published: July 2005

Abstract:  Oral lichen planus is rare in childhood, and only a few reports on this subject have appeared in the literature. Our objective was to report individual cases of oral lichen planus in childhood from our practice and to review the literature on this subject. We recruited patients younger than 18 years with oral lichen planus and documented several clinical aspects, the histopathology, patch tests, and blood examination findings. Three patients from about 10,000 dermatology patients younger than 18 years seen from 1994 to 2003 were included. Of these three, an Asian girl aged 11 years had an asymptomatic, hyperkeratotic variant of oral lichen planus, which disappeared without any treatment after 1 year. An Asian boy aged 16 years had an erosive oral lichen planus with severe pain, which healed after intensive local and systemic treatment in 2 years. A Caucasian girl aged 14 years had a hyperkeratotic variant with a little soreness, which disappeared with local treatment after 3 months. Our findings indicated that oral lichen planus in childhood is rare and therefore at present it is not possible to draw firm conclusions considering its nature and etiology. Oral lichen planus in childhood seems to occur preferentially in those of Asian race. The clinical features resemble those of oral lichen planus in adults. However, generally the prognosis of oral lichen planus in childhood seems to be more favorable than in adults.
High Incidence of Balanitis Xerotica Obliterans in Boys with Phimosis: Prospective 10‐Year Study
Authors: Kiss András , Király László , Kutasy Balázs , Merksz Miklós 
Published: July 2005

Abstract:  This prospective study was designed to address the incidence and clinical and histologic characteristics of balanitis xerotica obliterans in a large random pediatric population with phimosis. We investigated 1178 boys who presented consecutively with phimosis between 1991 and 2001. All patients who underwent complete circumcision and surgical specimens were typed histologically as early, intermediate, or late forms of this disorder or as nonspecific chronic inflammation. Patients with balanitis xerotica obliterans were controlled at 1, 6, and 12 months postoperatively, then yearly. Balanitis xerotica obliterans was found in 471 of the 1178 patients (40%), with the highest incidence in boys aged 9 to 11 years (76%). Secondary phimosis occurred in 93% of boys with balanitis xerotica obliterans and in 32% of those without the disorder. In six instances of balanitis xerotica obliterans, meatotomy and in one meatoplasty was performed, as well as circumcision. On histologic evaluation, we found 19% had early, 60% intermediate, and 21% late form of balanitis xerotica obliterans. Glanular lesions disappeared completely within 6 months in 229 out of 231 patients. Our data strongly suggest that the true incidence of childhood balanitis xerotica obliterans is higher than previously assumed. Its incidence peaks in the 9 to 11 years age group, in whom secondary phimosis was almost exclusively caused by balanitis xerotica obliterans.
G-CSF potently inhibits osteoblast activity and CXCL12 mRNA expression in the bone marrow
Authors: Semerad Craig L. , Christopher Matthew J. , Liu Fulu , Short Brenton , Simmons Paul J. , Winkler Ingrid , Levesque Jean-Pierre , Chappel Jean , Ross F. Patrick , Link Daniel C. 
Published: July 2005

AbstractAccumulating evidence indicates that interaction of stromal cell-derived factor 1 (SDF-1/CXCL12 [CXC motif, ligand 12]) with its cognate receptor, CXCR4 (CXC motif, receptor 4), generates signals that regulate hematopoietic progenitor cell (HPC) trafficking in the bone marrow. During granulocyte colony-stimulating factor (G-CSF)–induced HPC mobilization, CXCL12 protein expression in the bone marrow decreases. Herein, we show that in a series of transgenic mice carrying targeted mutations of their G-CSF receptor and displaying markedly different G-CSF–induced HPC mobilization responses, the decrease in bone marrow CXCL12 protein expression closely correlates with the degree of HPC mobilization. G-CSF treatment induced a decrease in bone marrow CXCL12 mRNA that closely mirrored the fall in CXCL12 protein. Cell sorting experiments showed that osteoblasts and to a lesser degree endothelial cells are the major sources of CXCL12 production in the bone marrow. Interestingly, osteoblast activity, as measured by histomorphometry and osteocalcin expression, is strongly down-regulated during G-CSF treatment. However, the G-CSF receptor is not expressed on osteoblasts; accordingly, G-CSF had no direct effect on osteoblast function. Collectively, these data suggest a model in which G-CSF, through an indirect mechanism, potently inhibits osteoblast activity resulting in decreased CXCL12 expression in the bone marrow. The consequent attenuation of CXCR4 signaling ultimately leads to HPC mobilization.
Platelet aggregation induces platelet aggregate stability via SLAM family receptor signaling
Authors: Nanda Nisha , Andre Patrick , Bao Ming , Clauser Karl , Deguzman Francis , Howie Duncan , Conley Pamela B. , Terhorst Cox , Phillips David R. 
Published: July 2005

AbstractPlatelet aggregation is a dynamic entity, capable of directing its own growth and stability via the activation of signaling cascades that lead to the expression and secretion of various secondary agonists. Here we show that the signaling pathways triggered during platelet aggregation include an intrinsic pro-thrombotic activity mediated by 2 homophilic adhesion molecules, CD84 and CD150 (SLAM [signaling lymphocyte activation molecule]), which are tyrosine phosphorylated in a platelet aggregation–dependent fashion. The 2 CD84/SLAM adapter proteins, SAP (SLAM-associated protein) and EAT-2 (EWS-activated transcript-2), were found in platelets; only SAP, however, was found to immunoprecipitate with tyrosine-phosphorylated SLAM. The immobilized extracellular domain of CD84 promoted microaggregate formation, while SAP-deficient platelets demonstrated defective spreading on immobilized CD84, demonstrating a functional role in platelets for SLAM family interactions. Finally, analysis of SLAM-deficient mice revealed an overall defect in platelet aggregation in vitro and a delayed arterial thrombotic process in vivo. The data indicate that signaling of the adhesion molecules in the SLAM family, activated by proximity during aggregation, further stabilize platelet-platelet interactions in thrombosis.