bluuebunny/crossref_metadata_2025_split huggingface dataset:
Y1 receptor of neuropeptide Y as a glial marker in proliferative vitreoretinopathy and diseased human retina
Authors: Soler M. Valeria Cantó , Gallo Juan E. , Dodds Ricardo A. , Hökfelt Tomas , Villar Marcelo J. , Suburo Angela M. 
Published: September 2002

AbstractThe Y1 receptor of neuropeptide Y (NPY) has been demonstrated in glial cells of astrocytic lineage in vitro. We have studied the immunohistochemical expression of Y1 receptors in the glia of the diseased human retina, in tissue samples obtained after surgery for proliferative vitreoretinopathy. In this condition, glia and other cell types migrate and form epi‐ or subretinal membranes. Both diseased retinas (n = 8) and PVR membranes (n = 43) contained numerous Y1‐immunoreactive cells. In the diseased retina, the Y1 antiserum labeled cells with the morphological radial pattern characteristic of Müller cells, whereas in the membranes, label appeared in a large population of elongate cells, measuring up to 250 μm. In both retina and membranes, double labeling demonstrated that the vast majority of Y1‐immunoreactive cells were also labeled by a glial fibrillary acidic protein (GFAP) antibody, indicating their glial origin. Retinal regions devoid of GFAP immunoreactivity also lacked the Y1 label. None of these markers was detected in Müller cells of normal retina. Y1 immunoreactivity did not co‐localize with smooth muscle actin immunoreactivity, a marker of myofibroblasts. Expression of Y1 receptors would characterize reactive and proliferating glial cells of the diseased retina and could perhaps be involved in the proliferation of injured glial cells causing regrowth of PVR membranes and the consequent secondary retinal detachments. GLIA 39:320–324, 2002. © 2002 Wiley‐Liss, Inc.
Functional melatonin receptors and metabolic coupling in cultured chick astrocytes
Authors: Adachi Akihito , Natesan Arjun K. , Whitfield‐Rucker Melissa G. , Weigum Shannon E. , Cassone Vincent M. 
Published: September 2002

AbstractMelatonin is an important hormone regulating circadian clocks in birds, but the specific cellular sites of action are not completely known. The present study was designed to determine whether astrocytes derived from chick brain contained functional melatonin receptors. Primary cell cultures of diencephalon astrocytes that express glial fibrillary acidic protein (GFAP), but not neuron‐specific enolase (NSE) immunoreactivity, were employed to determine the cellular distribution and physiological role for the three known receptor subtypes. Saturation and Scatchard analysis of 2‐[125I]iodomelatonin binding demonstrated melatonin receptor binding with a high affinity and a pharmacological profile similar to that obtained from brain. In situ hybridization for receptor subtypes revealed Mel1A and Mel1C receptor mRNA, but not Mel1B. Administration of pharmacological levels of melatonin acutely inhibited forskolin‐stimulated 2‐deoxyglucose (2DG) uptake, while rhythmic administration of physiological levels of melatonin gradually imposed a rhythm in 2DG uptake and of the release of both lactate and pyruvate into the medium. These results indicate that (1) there are functional Mel1A and Mel1C melatonin receptors in astrocyte‐rich cultures, and (2) rhythmic administration of melatonin plays an important role in the regulation of astrocytic metabolic activity. Together, the data suggest that the circadian secretion of melatonin probably plays a role in the global metabolic economy of the avian brain through rhythmic regulation of metabolism in astrocytes. GLIA 39:268–278, 2002. © 2002 Wiley‐Liss, Inc.
Kir potassium channel subunit expression in retinal glial cells: Implications for spatial potassium buffering†
Authors: Kofuji Paulo , Biedermann Bernd , Siddharthan Venkatraman , Raap Maik , Iandiev Ian , Milenkovic Ivan , Thomzig Achim , Veh Rüdiger W. , Bringmann Andreas , Reichenbach Andreas 
Published: September 2002

AbstractTo understand the role of different K+ channel subtypes in glial cell‐mediated spatial buffering of extracellular K+, immunohistochemical localization of inwardly rectifying K+ channel subunits (Kir2.1, Kir2.2, Kir2.3, Kir4.1, and Kir5.1) was performed in the retina of the mouse. Stainings were found for the weakly inward‐rectifying K+ channel subunit Kir4.1 and for the strongly inward‐rectifying K+ channel subunit Kir2.1. The most prominent labeling of the Kir4.1 protein was found in the endfoot membranes of Müller glial cells facing the vitreous body and surrounding retinal blood vessels. Discrete punctate label was observed throughout all retinal layers and at the outer limiting membrane. By contrast, Kir2.1 immunoreactivity was located predominantly in the membrane domains of Müller cells that contact retinal neurons, i.e., along the two stem processes, over the soma, and in the side branches extending into the synaptic layers. The results suggest a model in which the glial cell‐mediated transport of extracellular K+ away from excited neurons is mediated by the cooperation of different Kir channel subtypes. Weakly rectifying Kir channels (Kir4.1) are expressed predominantly in membrane domains where K+ currents leave the glial cells and enter extracellular “sinks,” whereas K+ influxes from neuronal “sources” into glial cells are mediated mainly by strongly rectifying Kir channels (Kir 2.1). The expression of strongly rectifying Kir channels along the “cables” for spatial buffering currents may prevent an unwarranted outward leak of K+, and, thus, avoid disturbances of neuronal information processing. GLIA 39:292–303, 2002. © 2002 Wiley‐Liss, Inc.
CD38 expression and NAD+‐induced intracellular Ca2+ mobilization in isolated retinal Müller cells
Authors: Esguerra Manuel , Miller Robert F. 
Published: September 2002

AbstractMüller cells of the vertebrate retina are prominent radial glia that provide essential support to sustain homeostasis of the tissue, including redistribution of external potassium, uptake and metabolism of neurotransmitters, and secretion of factors that stabilize the retina. Meeting this diversity of functional supports requires that Müller cells express numerous receptors, transporters, enzymes, and tissue factors. In this study, we provide evidence that adds to the dimensions of Müller cell function by demonstrating a unique relationship between external NAD+ and the mobilization of internal calcium, expressed in the form of calcium waves. The cellular mechanism that supports internal mobilization of calcium appears to depend on a complex multifunctional ectoenzyme, CD38, which converts NAD+ into the intracellular Ca2+‐mobilizing second‐messenger cyclic ADP‐ribose (cADPR) and could function as a detector for extracellular NAD+, thus providing a novel signal detection system for evaluating the extracellular environment. Our results are consistent with a model of intracellular Ca2+ mobilization in which membrane‐bound CD38 binds extracellular NAD+ and triggers intracellular Ca2+ waves either by direct conversion of NAD+ to cADPR or by activating intracellular cADPR synthesis. Our preliminary results indicate that the Ca2+ waves induced by external NAD+ propagate through an internal pathway that depends on the activation of ryanodine receptors, which appear to be distributed throughout the Müller cell cytosol. Because NAD+ is likely to be enhanced when cells are stress or damaged, CD38 could enable Müller cells to detect NAD+ under these circumstances and respond appropriately. Alternatively, NAD+ could also represent a novel extracellular, paracrine function that mediates signaling between glial cells and/or other cellular elements of the retina. GLIA 39:314–319, 2002. © 2002 Wiley‐Liss, Inc.
Motor cortex activation is related to force of squeezing
Authors: Cramer Steven C. , Weisskoff Robert M. , Schaechter Judith D. , Nelles Gereon , Foley Mary , Finklestein Seth P. , Rosen Bruce R. 
Published: September 2002

AbstractPrimate studies have demonstrated that motor cortex neurons show increased activity with increased force of movement. In humans, this relationship has received little study during a power grip such as squeezing, and has previously only been evaluated across a narrow range of forces. Functional MRI was performed in eight healthy subjects who alternated between rest and right hand squeezing at one of three force levels. During scanning, motor performances were recorded using a dynamometer. At each force level, activation volume was measured within left sensorimotor cortex, right sensorimotor cortex, and a midline supplementary motor area. In left sensorimotor cortex, % signal change was also assessed. The range of force generated across the three force levels varied from 4.9 N to 276 N. In left sensorimotor cortex, activation volume increased significantly with greater force. The % signal change also increased with greater force and correlated closely with activation volume. In supplementary motor area, activation volume increased significantly with increasing force, but with greater intersubject variability. In right sensorimotor cortex, a trend for larger activation volumes with greater force did not reach significance. The laterality index, an expression of the relative degree of contralateral vs. ipsilateral sensorimotor cortex activation, did not change across the three force levels. Increased force of squeezing is associated with increased contralateral sensorimotor cortex and supplementary motor area activation. This relationship was found across the full spectrum of forces that the human hand is capable of generating. Use of a valid, reliable method for assessing motor behavior during functional MRI may be important to clinical applications. Hum. Brain Mapping 16:197–205, 2002. © 2002 Wiley‐Liss, Inc.
Functional brain activation during arithmetic processing in females with fragile X syndrome is related to FMR1 protein expression
Authors: Rivera Susan M. , Menon Vinod , White Christopher D. , Glaser Bronwyn , Reiss Allan L. 
Published: September 2002

AbstractArithmetic processing deficits in persons with fragile X Syndrome (fraX), the most common heritable cause of mental retardation, are well known. In this study, we characterize the neural underpinnings of these performance deficits using functional MRI. Given that a single gene defect (FMR1) is known to be responsible for this disorder, we also assess whether brain activation in arithmetic processing areas is related to amount of FMR1 protein expression (FMRP). Subjects included 16 females with fraX, and 16 female age‐matched controls. Subjects viewed arithmetic equations with two (1 + 3 = 4) or three (2 + 3 − 1 = 5) operands, and were asked to judge whether the results were correct or not. Subjects with fraX showed significant impairment in behavioral performance on the 3‐operand but not the 2‐operand arithmetic equations. Significant brain activation was observed bilaterally in the prefrontal and parietal cortices for unaffected subjects, and bilateral prefrontal and left angular gyrus for subjects with fraX, for both trial types. Subjects with fraX exhibited less overall activation than did unaffected subjects in both types of trials; and, unlike the unaffected group, did not show increased extent of activation in association with greater task difficulty. During the 3‐operand trials, activation in bilateral prefrontal and motor/premotor, and left supramarginal and angular gyri were positively correlated with FMRP, suggesting that decreased FMR1 protein expression underlies deficits in math performance in persons with fraX. More broadly, this investigation demonstrates a unique bridging of cognitive and molecular neuroscience and represents a useful approach for the study of brain development and function. Hum. Brain Mapping 16:206–218, 2002. © 2002 Wiley‐Liss, Inc.
Modality independence of word comprehension
Authors: Booth James R. , Burman Douglas D. , Meyer Joel R. , Gitelman Darren R. , Parrish Todd B. , Mesulam M. Marsel 
Published: September 2002

AbstractFunctional magnetic resonance imaging (fMRI) was used to examine the functional anatomy of word comprehension in the auditory and visual modalities of presentation. We asked our subjects to determine if word pairs were semantically associated (e.g., table, chair) and compared this to a reference task where they were asked to judge whether word pairs rhymed (e.g., bank, tank). This comparison showed task‐specific and modality‐independent activation for semantic processing in the heteromodal cortices of the left inferior frontal gyrus (BA 46, 47) and left middle temporal gyrus (BA 21). There were also modality‐specific activations in the fusiform gyrus (BA 37) for written words and in the superior temporal gyrus (BA 22) for spoken words. Our findings are consistent with the hypothesis that word form recognition (lexical encoding) occurs in unimodal cortices and that heteromodal brain regions in the anterior as well as posterior components of the language network subserve word comprehension (semantic decoding). Hum. Brain Mapping 16:251–261, 2002. © 2002 Wiley‐Liss, Inc.
Dissecting an enzyme—model compounds for the galactose oxidase radical site
Authors: Halcrow Malcolm A. 
Published: September 2002

AbstractThe active site of the enzyme galactose oxidase (GOase) contains square‐pyramidal monocopper site, one of whose ligands is a tyrosinate side‐chain that is oxidized to an unusually stable radical in the active enzyme. The structure of this non‐innocent tyrosinate is unique in two ways. First, the tyrosine ring is crosslinked to a neighboring cysteine residue, affording an orthoalkylsulfanyl‐substituted phenoxide ligand. Second, this assembly is protected by a π–π interaction to a tryptophan indole group. We describe here a series of compounds designed to model various aspects of the structure of this unusual cofactor. Our studies have shown that the thermodynamic stability of the GOase radical can be attributed almost exclusively to its thioether substituent, that the π–π interaction contributes little to this stability, and that the assignment of the optical spectrum of the GOase radical is more complex than had been previously suggested. © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:494–500, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10091
PN ligands in lanthanide chemistry
Authors: Roesky Peter W. 
Published: September 2002

AbstractThe coordination chemistry of inorganic amides in Group 3 and lanthanide chemistry is discussed. Three different ligand systems (phosphino‐amides, bis(phosphino)amides, and bis(phosphinimino)methanides) that consist of one or more PN units were used. In this series the steric demand of the ligands is increased in a stepwise fashion and the negative charge is delocalized over more atoms. These properties were used in the design of new lanthanide complexes. For all three compounds the synthesis of the alkali metal derivatives is reported first, followed by the reaction of the alkali metal salts with various lanthanide trichlorides. Further reactions of the obtained lanthanide complexes as well as their application as catalysts are discussed. Most of the reported complexes show a dynamic behavior in solution. In phosphinoamide and bis(phosphino)amide complexes, in which the phosphorus atom is in oxidation state +3, there is always a weak coordination of the phosphorus atom to the lanthanide atom observed. In bis(phosphinimino)methanide complexes, in which the phosphorus atom is in oxidation state +5, no such interaction is noticeable. Instead a weak coordination of the methine atom to the center metal can be seen in the solid state. © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:514–520, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10096
Self‐assembly of anion‐binding supramolecular cage complexes
Authors: Paul Rowena L. , Bell Zöe R. , Fleming James S. , Jeffery John C. , McCleverty Jon A. , Ward Michael D. 
Published: September 2002

AbstractThree tetradentate ligands, in which two bidentate pyrazolyl–pyridine binding sites are connected by an aromatic spacer unit, have been used to prepare adamantoid tetrahedral cages of the form [Co4L6(X)][X]7 (where X is a uninegative, noncoordinating counterion such as perchlorate, tetrafluoroborate, or hexafluorophosphate). In these complexes an approximately tetrahedral array of metal ions occurs, with a bridging ligand spanning each of the six edges of this tetrahedron; each metal ion is accordingly six coordinate and the cages can have either T or C3 symmetry, depending on the ligand. The central cavity of each cage is occupied by an anion. In the cases where the anion is a good fit for the central cavity, it is tightly bound (no exchange in solution with external anions) and acts as a template for assembly of the cage, with a mixture of Co(II) and the bridging ligand in the correct proportions not assembling into the Co4L6 cage until the templating anion is added. With a longer bridging ligand, the central cavity is too large to encapsulate the anion completely, and accordingly the encapsulated anion can exchange freely with external anions; this behavior can be “frozen out” in the NMR spectra at low temperatures. The host–guest chemistry of the cage complexes is therefore strongly dependent on the size of the central cavity. © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:567–573, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10101
Silver(I) fluoride and related compounds in chemical synthesis
Authors: Tyrra Wieland 
Published: September 2002

AbstractSilver(I) fluoride is a versatile tool in desulfuration‐fluorination reactions with thiuram disulfides and thioureas. Reactions of AgF and trimethyl(perfluoroorgano)‐ and trimethyl(alkynyl)‐silanes offer a convenient approach to the corresponding organosilver derivatives, which are excellent reagents for oxidative organylations of group 12–16 elements. Reactions of AgF and elements of groups 13–16 open a convenient access to the corresponding fluorides. © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:561–566, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10102
Keeping nurses at work: a duration analysis
Authors: Holmås Tor Helge 
Published: September 2002

AbstractA shortage of nurses is currently a problem in several countries, and an important question is therefore how one can increase the supply of nursing labour. In this paper, we focus on the issue of nurses leaving the public health sector by utilising a unique data set containing information on both the supply and demand side of the market. To describe the exit rate from the health sector we apply a semi‐parametric hazard rate model. In the estimations, we correct for unobserved heterogeneity by both a parametric (Gamma) and a non‐parametric approach. We find that both wages and working conditions have an impact on nurses' decision to quit. Furthermore, failing to correct for the fact that nurses' income partly consists of compensation for inconvenient working hours results in a considerable downward bias of the wage effect. Copyright © 2002 John Wiley & Sons, Ltd.
Rational addiction to alcohol: panel data analysis of liquor consumption
Authors: Baltagi Badi H. , Griffin James M. 
Published: September 2002

AbstractUtilizing a panel data set of 42 states over the period 1959–1994, this paper estimates a rational addiction model for liquor consumption for the US. The empirical evidence is consistent with the rational addiction hypothesis proposed by Becker and Murphy. However, the results are sensitive to the assumption of homogeneity across states or over time. Copyright © 2002 John Wiley & Sons, Ltd.
Real‐time recurrent learning neural network for stream‐flow forecasting
Authors: Chang F.‐John , Chang Li‐Chiu , Huang Hau‐Lung 
Published: September 2002

AbstractVarious types of neural networks have been proposed in previous papers for applications in hydrological events. However, most of these applied neural networks are classified as static neural networks, which are based on batch processes that update action only after the whole training data set has been presented. The time variate characteristics in hydrological processes have not been modelled well. In this paper, we present an alternative approach using an artificial neural network, termed real‐time recurrent learning (RTRL) for stream‐flow forecasting. To define the properties of the RTRL algorithm, we first compare the predictive ability of RTRL with least‐square estimated autoregressive integrated moving average models on several synthetic time‐series. Our results demonstrate that the RTRL network has a learning capacity with high efficiency and is an adequate model for time‐series prediction. We also investigated the RTRL network by using the rainfall–runoff data of the Da‐Chia River in Taiwan. The results show that RTRL can be applied with high accuracy to the study of real‐time stream‐flow forecasting networks. Copyright © 2002 John Wiley & Sons, Ltd.
Effects of land‐cover changes on the hydrological response of interior Columbia River basin forested catchments
Authors: VanShaar James R. , Haddeland Ingjerd , Lettenmaier Dennis P. 
Published: September 2002

AbstractThe topographically explicit distributed hydrology–soil–vegetation model (DHSVM) is used to simulate hydrological effects of changes in land cover for four catchments, ranging from 27 to 1033 km2, within the Columbia River basin. Surface fluxes (stream flow and evapotranspiration) and state variables (soil moisture and snow water equivalent) corresponding to historical (1900) and current (1990) vegetation are compared. In addition a sensitivity analysis, where the catchments are covered entirely by conifers at different maturity stages, was conducted. In general, lower leaf‐area index (LAI) resulted in higher snow water equivalent, more stream flow and less evapotranspiration. Comparisons with the macroscale variable infiltration capacity (VIC) model, which parameterizes, rather than explicitly represents, topographic effects, show that runoff predicted by DHSVM is more sensitive to land‐cover changes than is runoff predicted by VIC. This is explained by model differences in soil parameters and evapotranspiration calculations, and by the more explicit representation of saturation excess in DHSVM and its higher sensitivity to LAI changes in the calculation of evapotranspiration. Copyright © 2002 John Wiley & Sons, Ltd.