bluuebunny/crossref_metadata_2025_split huggingface dataset:
Matrix metalloproteinase‐dependent shedding of syndecan‐3, a transmembrane heparan sulfate proteoglycan, in Schwann cells
Authors: Asundi Vinod K. , Erdman Robert , Stahl Richard C. , Carey David J. 
Published: August 2003

AbstractSchwann cells transiently express the transmembrane heparan sulfate proteoglycan syndecan‐3 during the late embryonic and early postnatal periods of peripheral nerve development. Neonatal rat Schwann cells released soluble syndecan‐3 into the culture medium by a process that was blocked by inhibition of endogenous matrix metalloproteinase activity. When Schwann cells were plated on a substratum that binds syndecan‐3, the released proteoglycan bound to the substratum adjacent to the cell border. Membrane‐anchored syndecan‐3 was concentrated in actin‐containing filopodia that projected from the lateral edges of the Schwann cell membrane. Membrane shedding was specific for syndecan‐3 and was not observed for the related proteoglycan syndecan‐1. Analysis of Schwann cells transfected with wild‐type and chimeric syndecan‐1 and syndecan‐3 cDNAs revealed that membrane shedding was a property of the syndecan‐3 ectodomain. Inhibition of syndecan‐3 release significantly enhanced Schwann cell adhesion and process extension on dishes coated with the non‐collagenous N‐terminal domain of α4(V) collagen, which binds syndecan‐3 and mediates heparan sulfate‐dependent Schwann cell adhesion. Matrix metalloproteinase‐dependent syndecan‐3 shedding was also observed in newborn rat peripheral nerve tissue. Syndecan‐3 shedding in peripheral nerve tissue was age specific, and was not observed during later stages of postnatal nerve development. These results demonstrate that Schwann cell syndecan‐3 is subject to matrix metalloproteinase‐dependent membrane processing, which modulates the biological function of this proteoglycan. © 2003 Wiley‐Liss, Inc.
Macrophages contribute to the maintenance of stable regenerating neurites following peripheral nerve injury
Authors: Luk Hoenie W. , Noble Linda J. , Werb Zena 
Published: August 2003

AbstractNormal adult uninjured nerve is unable to support axonal regeneration. We have studied the mechanisms underlying the regeneration of peripheral nerve by culturing adult mouse dorsal root ganglia (DRG) explants on unfixed, longitudinal cryosections of either the uninjured sciatic nerve or the distal segment of the transected sciatic nerve. We found that, initially, DRG grew vigorously on cryosections of both uninjured and postinjury sciatic nerves. However, the neurites began to degenerate shortly after contact with the uninjured nerve, whereas those growing on postinjury nerve substrate remained healthy for up to 9 days in culture. This ability to support stable outgrowth peaked at 8 days, gradually decreased by 10 days, and disappeared by 20 days after injury. Macrophages appeared in the distal segment by 4 days postinjury and had infiltrated its entire length by 8 days. Uninjured nerve cryosections could be rendered supportive of stable outgrowth by preincubation with macrophage‐conditioned medium or by brief trypsinization. The activity of the macrophage‐conditioned medium was augmented upon activation of macrophages. Together these findings suggest that the environment of the sciatic nerve undergoes a transformation during Wallerian degeneration such that it becomes transiently supportive of the stable outgrowth of neurites. This transformation may be mediated by a proteolytic activity, generated by activated macrophages, that removes a putative “degeneration signal” protein normally present in the adult nerve and thus contributes to the maintenance of stable regenerating neurites. © 2003 Wiley‐Liss, Inc.
Characterization of the toxic mechanism triggered by Alzheimer's amyloid‐β peptides via p75 neurotrophin receptor in neuronal hybrid cells
Authors: Tsukamoto Emi , Hashimoto Yuichi , Kanekura Kohsuke , Niikura Takako , Aiso Sadakazu , Nishimoto Ikuo 
Published: August 2003

AbstractNeuronal pathology of the brain with Alzheimer's disease (AD) is characterized by numerous depositions of amyloid‐β peptides (Aβ). Aβ binding to the 75‐kDa neurotrophin receptor (p75NTR) causes neuronal cell death. Here we report that Aβ causes cell death in neuronal hybrid cells transfected with p75NTR, but not in nontransfected cells, and that p75NTRL401K cannot mediate Aβ neurotoxicity. We analyzed the cytotoxic pathway by transfecting pertussis toxin (PTX)‐resistant G protein α subunits in the presence of PTX and identified that Gαo, but not Gαi, proteins are involved in p75NTR‐mediated Aβ neurotoxicity. Further investigation suggested that Aβ neurotoxicity via p75NTR involved JNK, NADPH oxidase, and caspases‐9/3 and was inhibited by activity‐dependent neurotrophic factor, insulin‐like growth factor‐I, basic fibroblast growth factor, and Humanin, as observed in primary neuron cultures. Understanding the Aβ neurotoxic mechanism would contribute significantly to the development of anti‐AD therapies. © 2003 Wiley‐Liss, Inc.
Rapid increase of Nurr1 expression in the substantia nigra after 6‐hydroxydopamine lesion in the striatum of the rat
Authors: Ojeda Viviana , Fuentealba José Antonio , Galleguillos Danny , Andrés María Estela 
Published: August 2003

AbstractNurr1 is a transcription factor essential for the genesis of ventral dopaminergic neurons. In this study, we investigated the expression of Nurr1 protein and mRNA in the adult rat brain by using immunohistochemistry and in situ hybridization, respectively. Another aim of our study was to investigate Nurr1 expression in substantia nigra after dopamine depletion induced by the injection of 6‐hydroxydopamine in the striatum. We observed that Nurr1 mRNA and protein are expressed in several brain regions, including cortex, hippocampus, substantia nigra, and ventral tegmental area, in agreement with previous reports using in situ hybridization. Additionally, we found that Nurr1 is expressed in brain regions that have not been previously reported, such as striatum, septum, and superior colliculus. Highest levels of expression were found in cortex, medial septum, dentate gyrus, some hypothalamic nuclei, and substantia nigra. Interestingly, we observed that, in the superior colliculus, Nurr1 protein is localized in the cytoplasm of cells, whereas, in other regions, it was localized mainly in the nuclei, suggesting that Nurr1 subcellular localization is regulated and may have functional implications. Dopamine depletion induced by an injection of 6‐hydroxydopamine into the striatum produced an increase in the number of cells expressing Nurr1 mRNA and protein in both substantia nigra compacta and substantia nigra reticulata, ipsilateral and contralateral to the lesioned side, measured 24 hr after the 6‐hydroxydopamine injection. These results suggest that Nurr1 may be involved in many neuronal functions in the adult central nervous system and, in particular, might be related to the compensation processes that take place in dopaminergic cells in order to normalize extracellular dopamine levels in the striatum. © 2003 Wiley‐Liss, Inc.
Synergistic expression of inducible nitric oxide synthase by phorbol ester and interferon‐γ is mediated through NF‐κB and ERK in microglial cells
Authors: Han Inn‐Oc , Kim Hee‐Sun , Kim Hyoung‐Chun , Joe Eun‐Hye , Kim Won‐Ki 
Published: August 2003

AbstractA proinflammatory cytokine IFN‐γ stimulates microglia in the injured brain; however, signaling pathways for IFN‐γ‐mediated microglia activation are not well characterized. In the present study, a protein kinase C (PKC) activator phorbol 12‐myristate 13‐acetate (PMA) acts in concert with IFN‐γ to enhance nitric oxide (NO) production in murine microglial BV2 cells by synergistically increasing expression of inducible NO synthase (iNOS). The synergistic NO production by PMA was in part decreased by a PKC inhibitor Gö6976. PMA alone induced activation of nuclear factor‐kappa B (NF‐κB) and extracellular signal‐regulated kinase (ERK) of mitogen‐activated protein kinases (MAPKs) subtypes, whereas IFN‐γ alone had little effect. PMA and IFN‐γ synergistically enhanced activity of NF‐κB, but not ERK. The inhibitors of NF‐κB (pyrrolidine dithiocarbamate, PDTC) and ERK (1,4‐diamino‐2,3‐dicyano‐1,4 bis[2‐aminophenylthio]butadiene; U0126) markedly decreased synergistic NO production in BV2 cells treated with IFN‐γ and PMA in combination. We found further that co‐treatment with IFN‐γ and PMA synergistically induced interferon regulatory factor‐1 (IRF‐1), which is the major transcription factor for IFN‐γ‐mediated iNOS expression. The present results demonstrate the cooperative interaction of multiple signaling pathways in the induction of NO production in activated microglial cells, and suggest that the functional interplay of these pathways may be important for the onset of microglia‐mediated inflammatory responses in brain. © 2003 Wiley‐Liss, Inc.
Relationships between cholinergic phenotype and acetyl‐CoA level in hybrid murine neuroblastoma cells of septal origin
Authors: Bielarczyk Hanna , Tomaszewicz Maria , Madziar Beata , Ćwikowska Justyna , Pawełczyk Tadeusz , Szutowicz Andrzej 
Published: August 2003

AbstractHigh susceptibility of cholinergic neurons to neurotoxic signals may result from their utilization of acetyl‐CoA for both energy production and acetylcholine synthesis. SN56 cholinergic cells were transfected stably with cDNA for choline acetyltransferase. Transfected cells (SN56ChAT2) expressed choline acetyltransferase activity and acetylcholine content, 17 times and 2 times higher, respectively, than did nontransfected cells. Transfection did not change pyruvate dehydrogenase but decreased the acetyl‐CoA level by 62%. Differentiation by cAMP and retinoic acid caused an increase of choline acetyltransferase activity and decrease of acetyl‐CoA levels in both cell lines. Negative correlation was found between choline acetyltransferase activity and acetyl‐CoA level in these cells. SN56ChAT2 cells were more susceptible to excess NO than were native SN56 cells, as evidenced by the thiazolyl blue reduction assay. Thus, the sensitivity of cholinergic neurons to pathologic conditions may depend on the cholinergic phenotype‐dependent availability of acetyl‐CoA. © 2003 Wiley‐Liss, Inc.
Evidence for a second wave of oligodendrogenesis in the postnatal cerebral cortex of the mouse
Authors: Ivanova Anna , Nakahira Eiko , Kagawa Tetsushi , Oba Akio , Wada Tamaki , Takebayashi Hirohide , Spassky Nathalie , Levine Joel , Zalc Bernard , Ikenaka Kazuhiro 
Published: August 2003

AbstractThe existing view is that cortical oligodendrocytes (OLs) in rodents are born from the cortical subventricular zone (SVZ) after birth, but recent data suggest that many forebrain oligodendrocyte progenitor cells (OPCs) are specified much earlier (between E9.5 and E13.5 in the mouse) in the ventricular zone of the ventral forebrain under the control of sonic hedgehog (Shh) and migrate into the cortex afterward. We examined expression of specific early OL markers (PDGFRα, PLP/DM20, Olig2, and NG2) in the developing forebrain to clarify this issue. We propose that OPCs colonize the developing cortex in two temporally distinct waves. The gray matter is at least partially populated by a first wave of OPCs that arises in the medial ganglionic eminence and the entopeduncular area and spreads into the cortex via the developing cortical plate. The cerebral cortex benefits from the second wave of OPCs coming from residential SVZ. In the second wave, there might be two different types of precursor cells: PLP/DM20+ cells populating only inner layers and PDGFRα+ cells, which might eventually myelinate the outer regions as well. © 2003 Wiley‐Liss, Inc.
Differentiating work autonomy facets in a non‐Western context
Authors: Sadler‐Smith Eugene , El‐Kot Ghada , Leat Mike 
Published: August 2003

AbstractWork autonomy is one important component of job design theory which in recent decades has been elaborated upon by a number of researchers who have argued that it may be disaggregated into separate work method, work schedule and work criterion autonomy facets. Breaugh (1985) developed the Work Autonomy Scales as measures of each of these. This article reports the results of two studies carried out in Egypt that explored the validity of Breaugh's scales in relation to job design theory. In Study 1, in which Breaugh's scales were administered to 534 employees in two large Egyptian organizations, the Work Autonomy Scales' three‐factor structure was verified using exploratory and confirmatory factor analyses. In Study 2, using a sample of 120 managers from four organizations, the associations between the three facets of work autonomy and other variables with which they would be expected to correlate, along with their relationships with a number of outcome variables, were explored. Statistically significant correlations were observed between certain of the work autonomy scales and task interdependence, Hackman and Oldham's autonomy scale and job complexity. In terms of outcomes, work schedule autonomy was associated with job commitment, while work criterion autonomy was associated with job satisfaction. The results are discussed in the light of previous findings and some suggestions for future research are offered. Copyright © 2003 John Wiley & Sons, Ltd.
Factor structure of the transformational leadership model in human service teams
Authors: Garman Andrew N. , Davis‐Lenane Deborah , Corrigan Patrick W. 
Published: August 2003

AbstractThe purpose of this study was to examine the factor structure of the transformational leadership model in human service teams. As the nature of this work environment mandates certain management‐by‐exception practices, patterns of correlations between perceptions of active and passive management‐by‐exception behaviors and transformational, transactional, and laissez‐faire leadership were of interest. 236 leaders and 620 subordinates from 54 mental health teams completed the Multifactor Leadership Questionnaire, form 8Y. Results suggest that active and passive management‐by‐exception factors are independent constructs. Copyright © 2003 John Wiley & Sons, Ltd.
Group absenteeism and positive affective tone: a longitudinal study
Authors: Mason Claire M. , Griffin Mark A. 
Published: August 2003

AbstractThis study investigates temporal variation in group absence behavior, and the relationship between group absenteeism and the group's positive affective tone. Absenteeism data were obtained from 97 work groups, aggregated over each of the four quarters of a year. The group's positive affective tone was measured through two employee opinion surveys. Multi‐level regression analyses were carried out, in which linear, quadratic, and cubic change trends were tested as predictors of change over time in group absenteeism. All three change trends explained unique variance in the group absenteeism data, indicating that the level of group absenteeism changes over time. We also found that there was significant variation between groups in the strength and direction of the linear and quadratic change trends. Positive affective tone was negatively related to the level of group absenteeism, and change in positive affective tone predicted the strength and direction of the linear change trend for group absenteeism. Copyright © 2003 John Wiley & Sons, Ltd.
Predictors of success in the era of the boundaryless career
Authors: Eby Lillian T. , Butts Marcus , Lockwood Angie 
Published: August 2003

AbstractThe present study examines three classes of career competencies proposed as important predictors of success in the boundaryless career. Three criteria of career success were examined: perceived career satisfaction, perceived internal marketability, and perceived external marketability. Using data from 458 alumni from a large southeastern university, predictions were tested using partial correlations and dominance analysis. The results found support for the importance of ‘knowing why,’ ‘knowing whom,’ and ‘knowing how’ as suggested by previous theoretical work. The findings are discussed in reference to future research and theorizing on the boundaryless career. Copyright © 2003 John Wiley & Sons, Ltd.
Firm reputation and applicant pool characteristics
Authors: Turban Daniel B. , Cable Daniel M. 
Published: August 2003

AbstractScholars have suggested that a firm's reputation can provide it with a competitive advantage by attracting more, and possibly higher‐caliber, applicants. No research has actually investigated this relationship, however, in large part because researchers have not assessed applicant pool characteristics but instead have measured applicants' intentions. Therefore, we conducted two studies to investigate whether organizational reputation influenced the number and the quality of applicants actually seeking positions with firms. Company reputation was operationalized using two different published reputation measures, and applicant quality data were obtained from career services offices at business schools at two universities. Results from both studies supported the previously untested belief that firms with better reputations attract more applicants. Furthermore, some evidence suggested that firms with better reputations could select higher‐quality applicants. Copyright © 2003 John Wiley & Sons, Ltd.
Why do lay people believe that satisfaction and performance are correlated? possible sources of a commonsense theory
Authors: Fisher Cynthia D. 
Published: August 2003

AbstractDecades of research have shown that the correlation between job satisfaction and job performance is modest in magnitude, yet lay people are thought to believe strongly that satisfied or ‘happy’ employees are more productive at work. This paper first documents the strength and pervasiveness of belief in several versions of the happy–productive worker hypothesis (Study 1), then proposes and explores potential substantive explanations for these beliefs (Study 2). It is possible that lay people base their beliefs on genuinely stronger relationships that occur at a different level of analysis than usually studied by researchers, and/or that exist between satisfaction‐like and performance‐like variables other than the constructs typically investigated by scholars. Study 2 provides data relevant to several of these possibilities. The most compelling findings were at the within‐person level of analysis. The average within‐person correlation between momentary task satisfaction and concurrent perceived task performance was 0.57. Individuals feel more satisfied than usual when they believe they are performing better than usual for them. If lay persons mistakenly generalize from their own within‐person experiences of satisfaction–performance covariation to the between‐persons level, this relationship may be the basis for the strong lay belief that satisfied workers perform better. Copyright © 2003 John Wiley & Sons, Ltd.
Diversity and team outcomes: the moderating effects of outcome interdependence and group longevity and the mediating effect of reflexivity
Authors: Schippers Michaéla C. , Den Hartog Deanne N. , Koopman Paul L. , Wienk Janique A. 
Published: August 2003

AbstractReflexivity—the extent to which teams reflect upon and modify their functioning—has been identified as a possible key factor in the effectiveness of work teams. We examined the extent to which team composition affected team process (i.e., reflexivity) and in turn team outcomes (i.e., satisfaction, commitment, and performance). The results of diversity research thus far have been inconclusive in terms of positive or negative effects of team composition on team process and outcomes. In the current research, group longevity and outcome interdependence were expected to moderate the relationship between diversity on the one hand and reflexivity and team outcomes on the other hand. Reflexivity was expected to mediate these interaction effects. The current field study was conducted among 54 work teams from 13 different organizations. As predicted, few main effects were found. Instead, analyses showed interaction effects of diversity and outcome interdependence on the measures of reflexivity, satisfaction, and performance. As predicted, interaction effects were also found for diversity and group longevity on the measures of reflexivity, satisfaction, and performance. Three‐way interactions were found for satisfaction and commitment. Also, reflexivity was shown to mediate these relationships, indicating that the moderating effects of outcome interdependence and group longevity on the relation between diversity and team outcomes are due to the effects on process. Copyright © 2003 John Wiley & Sons, Ltd.
Tephrochronology and tephrostratigraphy of two Pleistocene continental fossiliferous successions from central Italy
Authors: Marcolini F. , Bigazzi G. , Bonadonna F. P. , Centamore E. , Cioni R. , Zanchetta G. 
Published: August 2003

AbstractThe stratigraphical context of two Middle Pleistocene fossiliferous palaeosols from Central Italy (Abruzzo and Tuscany) have been studied. Small mammals and molluscs occur in both palaeosols, which are covered by tephra layers that were analysed using an interdisciplinary approach. Application of fission‐track dating to apatites separated from the Case Picconetto tephra (Pescara, Abruzzo), yielded an age of 0.48 ± 0.04 Ma, indistinguishable from those previously determined for the Campani Quarry (Lower Valdarno, Tuscany) (0.46 ± 0.05 Ma and 0.48 ± 0.05 Ma). Geochemical and petrographic investigations indicate that these tephra originated from different volcanoes, the Alban Hills Volcanic Complex and the Vico Volcano (Latium) respectively. Small mammal and mollusc assemblages indicate different palaeoclimatic and palaeoenvironmental conditions for the Case Picconetto and Campani Quarry palaeosols. Warm and humid conditions can be inferred for the Campani Quarry site, whereas open and cold conditions can be inferred for Case Picconetto. On the basis of faunal data, fission‐track dates and attribution of tephra to specific volcanic eruptions, we suggest a correlation of these faunas with marine oxygen isotope stage 14 (Case Picconetto) and with marine oxygen isotope stage 11 (Campani Quarry), respectively. Copyright © 2003 John Wiley & Sons, Ltd.
A late Holocene record of arid events from the Cuzco region, Peru
Authors: Chepstow‐Lusty Alex , Frogley Michael R. , Bauer Brian S. , Bush Mark. B. , Herrera Alfredo Tupayachi 
Published: August 2003

AbstractThe small recently infilled lake basin of Marcacocha (13°13′S, 72°12′W, 3355 m) in the Cuzco region of Peru has a morphology and location that renders it extremely sensitive to environmental change. A record of vegetation, human impact and climatic change during the past 4200 yr has been obtained from a highly organic core taken from the centre of the basin. Sustained arid episodes that affected the Peruvian Andes may be detectable using the proxy indicator of sedge (Cyperaceae) pollen abundances. As the lake‐level was lowered during sustained drier conditions, the local catchment was colonised by Cyperaceae, whereas during lake floods, they retreated or were submerged and pollen production was correspondingly reduced. Drier episodes during prehistoric times occurred around 900 bc, 500 bc, ad 100 and ad 550, with a longer dry episode occurring from ad 900 to 1800. Evidence from the independently derived Quelccaya ice‐core record and the archaeological chronology for the Cuzco region appears to support the climatic inferences derived from the sedge data. Many of these aridity episodes appear to correspond with important cultural changes in the Cuzco region and elsewhere in the Central Andes. Copyright © 2003 John Wiley & Sons, Ltd.