bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cyclin‐dependent kinase 5 (cdk5) activation requires interaction with three domains of p35
Authors: Amin Niranjana D. , Albers Wayne , Pant Harish C. 
Published: August 2002

AbstractCyclin‐dependent kinase 5 (cdk5), in contrast to other members of the cyclin‐dependent kinase family, is not activated by cyclins but instead is activated by complexing with neuron‐specific activator molecules (p35, p39, and p67). The most effective activator of cdk5 both in vitro and in vivo is p35. We have taken a kinetic approach to study the interaction between p35, its various truncated forms, and cdk5 to understand better the mechanism of its activation. The cdk5 complexes formed with the truncated forms p25 and p21 produced similar maximum active kinase, whereas the cdk5 complexed with full‐length p35 and a further truncated form spanning amino acid residues from 138 to 291, with approximate molecular weight of 16 kDa (p16), produced slightly less (80%) activation than p25. P16 was the smallest fragment of p35 that produced activation equal to or greater than that of full‐length p35. By examination of further truncations of p16, we found that a small number of residues, 11 and 4 at the N‐ and C‐termini, respectively, of p16, are essential for cdk5 activation. Further truncation, removing both essential N‐ and C‐terminal domains, produces a peptide with markedly higher affinity for cdk5 compared with the peptides that retain either of these domains. Using these inactive truncated peptides as inhibitors, we examined the kinetics of activation. From these studies we conclude that activation involves at least three cdk5‐interacting domains, one located at each end of p16 and at least one located in a central domain. The cdk5 activation process is slow: The second‐order rate constant for p16 is about 1.2 μM−1 hr−1. On the basis of kinetic data, we suggest that cdk5 exists in two conformations. The inactive kinase conformation predominates in the absence of the activator. Activation occurs in two stages: a rapid and reversible interaction of cdk5 with its activator, which involves only one or two binding domains, followed by a slow stabilization of the active conformation as interaction with all three domains is achieved. Published 2002 Wiley‐Liss, Inc.
Lack of prion protein expression results in a neuronal phenotype sensitive to stress
Authors: Brown David R. , Nicholas Richard St.J. , Canevari Laura 
Published: August 2002

AbstractThe prion protein is a highly conserved glycoprotein expressed most highly in the synapse. Evidence has recently been put forward to suggest that the prion protein is an antioxidant. However, the functional importance of the prion protein has been disputed; it is claimed that mice genetically ablated to lack prion protein expression are normal and have no specific phenotype. We have reexamined the phenotype of prion protein knockout mice and found that there are multiple biochemical changes in the mice, including increased levels of nuclear factor NF‐κB and Mn superoxide dismutase, COX‐IV decreased levels of Cu/Zn superoxide dismutase activity, decreased p53, and altered melatonin levels. Additionally, cultured cells from these mice are more sensitive to a range of insults, all linked to increased neuronal sensitivity to oxidative stress. These results imply that prion protein knockout mice are more sensitive to oxidative stress and have an altered phenotype that must be taken into account when considering the additional effects of increased levels of proteins such as Doppel. The implication of these results is that the consequence of genetic ablation of genes must include biochemical analysis as well as analyses of possible developmental and behavioral changes. © 2002 Wiley‐Liss, Inc.
Expression of Concern: Transient expression of fluorescent tau proteins promotes process formation in PC12 cells: Contributions of the tau C‐terminus to this process
Authors: Yu Jiang‐Zhou , Kuret Jeff , Rasenick Mark M. 
Published: August 2002

AbstractThe neuronal microtubule‐associated protein tau promotes microtubule assembly and has been implicated in the development of axonal morphology. In this study, PC12 cells were transiently transfected with constructs coding fusion proteins of human tau with green fluorescent protein (GFP). Expression of tau constructs actively stabilized microtubules. Expression of the C‐terminus of tau can mimic this effect in living cells, though to a lesser extent because of the absence of the tau N‐terminus. However, tau colocalization with microtubules did not require the presence of the tau N‐terminus. Transient expression of tau (including tau24, a four‐repeat human tau isoform encoded in 383 residues, and tau23, human fetal tau isoform encoded in 352 residues) stimulated process formation in PC12 cells, and this occurred faster with tau24 than with tau23. The residues (residues 154–172 in tau23) that confer microtubule nucleation activity of tau in vitro are not required for tau‐directed process formation. However, when tau induces the formation of cellular processes in response to cortical breakdown by cytochalasin B, residues 154–172 must be present. Thus, it appears that tau may serve to promote cellular process outgrowth in cultured neuronal cells and that C‐terminus of tau is essential to this process. © 2002 Wiley‐Liss, Inc.
Differential neuropathological alterations in transgenic mice expressing α‐synuclein from the platelet‐derived growth factor and Thy‐1 promoters
Authors: Rockenstein Edward , Mallory Margaret , Hashimoto Makoto , Song David , Shults Clifford W. , Lang Ingrid , Masliah Eliezer 
Published: August 2002

AbstractAccumulation of α‐synuclein has been associated with neurodegenerative disorders, such as Lewy body disease and multiple system atrophy. We previously showed that expression of wild‐type human α‐synuclein in transgenic mice results in motor and dopaminergic deficits associated with inclusion formation. To determine whether different levels of human α‐synuclein expression from distinct promoters might result in neuropathology mimicking other synucleopathies, we compared patterns of human α‐synuclein accumulation in the brains of transgenic mice expressing this molecule from the murine Thy‐1 and platelet‐derived growth factor (PDGF) promoters. In murine Thy‐1‐human α‐synuclein transgenic mice, this protein accumulated in synapses and neurons throughout the brain, including the thalamus, basal ganglia, substantia nigra, and brainstem. Expression of human α‐synuclein from the PDGF promoter resulted in accumulation in synapses of the neocortex, limbic system, and olfactory regions as well as formation of inclusion bodies in neurons in deeper layers of the neocortex. Furthermore, one of the intermediate expresser lines (line M) displayed human α‐synuclein expression in glial cells mimicking some features of multiple system atrophy. These results show a more widespread accumulation of human α‐synuclein in transgenic mouse brains. Taken together, these studies support the contention that human α‐synuclein expression in transgenic mice might mimic some neuropathological alterations observed in Lewy body disease and other synucleopathies, such as multiple system atrophy. © 2002 Wiley‐Liss, Inc.
Cannabinoid receptor agonist‐stimulated [35S]guanosine triphosphateγs binding in the brain of C57BL/6 and DBA/2 mice
Authors: Basavarajappa Balapal S. , Hungund Basalingappa L. 
Published: August 2002

AbstractThe two inbred strains of mice C57BL/6 (alcohol‐preferring) and DBA/2 (alcohol‐avoiding) mice have been shown to differ significantly in their preference for alcohol (EtOH). We have previously demonstrated the differences in the density and the affinity of cannabinoid (CB1) receptors in the brains of the two inbred C57BL/6 and DBA/2 mouse strains. In the present study, we investigated the CB1 receptor agonist‐stimulated guanosine‐5′‐O‐(3‐[35S]thio)‐triphosphate ([35S]GTPγS) binding in plasma membranes (PM) from C57BL/6 and DBA/2 mice. The results indicate that the net CP55,940‐stimulated [35S]GTPγS binding was increased with increasing concentrations of CB1 receptor agonists and GDP. The net CB1 receptor agonist (WIN55,212‐2 or HU‐210 or CP55,940)‐stimulated [35S]GTPγS binding was reduced significantly (–10% to –12%, P < 0.05) in PM from DBA/2 mice; no significant differences were observed in basal [35S]GTPγS binding among these strains. Nonlinear regression analysis of net CP55,940‐stimulated [35S]GTPγS binding showed that the Bmax of cannabinoid agonist‐stimulated binding was significantly reduced (–24%) in DBA/2 mice (Bmax = 12.43 ± 0.64 for C57BL/6 and 9.46 ± 0.98 pmol/mg protein for DBA/2; P < 0.05) without any significant changes in the G protein affinity. The pharmacological specificity of CP55,940‐stimulated [35S]GTPγS binding was examined with CB1 receptor antagonist SR141716A, and these studies indicated that CP55,940‐stimulated [35S]GTPγS binding was blocked by SR141716A, with a decrease in the IC50 values in the PM from the DBA/2 mouse strain. These results suggest that a signal transduction pathway(s) downstream from the CB1 receptor system may play an important role in controlling the voluntary EtOH consumption by these strains of mice. J. Neurosci. Res. 64:429–436, 2001. © 2001 Wiley‐Liss, Inc.
In vitro model of microglial deramification: Ramified microglia transform into amoeboid phagocytes following addition of brain cell membranes to microglia‐astrocyte cocultures
Authors: Bohatschek Marion , Kloss Christian U.A. , Kalla Roger , Raivich Gennadij 
Published: August 2002

AbstractChanges in the morphology of ramified microglia are a common feature in brain pathology and culminate in the appearance of small, rounded, microglia‐derived phagocytes in the presence of neural debris. Here, we explored the effect of adding brain cell membranes on the morphology of αMβ2‐integrin (CD11b/CD18, CR3) positive microglia cultured on a confluent astrocyte substrate as an in vitro model of deramification. Addition of brain membranes led to a loss of microglial ramification, with full transformation to small, rounded, macrophages at 20–40 μg/ml. Time course studies showed a rapid response, with first effects at 1–3 hours, and full transformation at 24–48 hours. Removal of cell membranes and exchange of the culture medium led to a similarly rapid process of reramification. Comparison of cell membranes from different tissues at 20 μg/ml showed strong transforming effect for the brain, more moderate for kidney and liver, and very weak for spleen and skeletal muscle. Fluorescent labeling of brain membranes revealed uptake by almost all rounded macrophages, by a subpopulation of glial fibrillary acidic protein (GFAP)‐positive astrocytes, but not by ramified microglia. Phagocytosis of inert fluorobeads did not lead to a transformation into macrophages but their phagocytosis was inhibited by brain membranes, pointing to a saturable uptake mechanism. In summary, addition of brain cell membranes and their phagocytosis leads to a rapid and reversible loss of ramification. The differences in transforming activity from different tissues and the absence of effect from phagocytosed fluorobeads suggest, however, the need for a second stimulus following the phagocytosis of cell debris. J. Neurosci. Res. 64:508–522, 2001. © 2001 Wiley‐Liss, Inc.
Antibodies directed against rubella virus induce demyelination in aggregating rat brain cell cultures
Authors: Besson Duvanel Cécile , Honegger Paul , Matthieu Jean‐Marie 
Published: August 2002

AbstractTo link the presence of intrathecal virus‐specific oligoclonal immunoglobulin G (IgG) in multiple sclerosis patients to a demyelinating activity, aggregating rat brain cell cultures were treated with antibodies directed against two viruses, namely, rubella (RV) and hepatitis B (HB). Anti‐RV antibodies in the presence of complement decreased myelin basic protein concentrations in a dose‐dependent manner, whereas anti‐HB antibodies had no effect. A similar but less pronounced effect was observed on the enzymatic activity of 2′,3′‐cyclic nucleotide 3′‐phosphohydrolase, which is enriched in noncompact membranes of oligodendrocytes. These effects were comparable to those in cultures treated with antibodies directed against myelin oligodendrocyte glycoprotein (MOG), previously found to be myelinotoxic both in vitro and in vivo. Sequence homologies were found between structural glycoprotein E2 of RV and MOG, suggesting that demyelination was due to molecular mimicry. To support the hypothesis that demyelination was caused by anti‐RV IgG that recognized an MOG epitope, we found that anti‐RV antibodies depleted MOG in a dose‐dependent manner. Further evidence came from the demonstration that anti‐RV and anti‐MOG IgG colocalized on oligodendrocyte processes and that both revealed by Western blot a 28 kDa protein in CNS myelin, a molecular weight corresponding to MOG. These findings suggest that a virus such as RV exhibiting molecular mimicry with MOG can trigger an autoimmune demyelination. J. Neurosci. Res. 65:446–454, 2001. © 2001 Wiley‐Liss, Inc.
Ammonia‐induced production of free radicals in primary cultures of rat astrocytes
Authors: Murthy C.R.K. , Rama Rao K.V. , Bai Ge , Norenberg Michael D. 
Published: August 2002

AbstractElevated levels of ammonia in blood and brain result in derangement of cerebral function. Recently, lipid peroxidation and oxidative stress have been implicated in ammonia neurotoxicity. Because ammonia is primarily detoxified in astrocytes, we postulated that pathophysiological concentrations of ammonia might induce free radical formation in these cells. To test this hypothesis, we examined the extent of free radical production in primary cultures of astrocytes that had been preloaded with the fluorescent dye 5‐ (and 6‐)carboxy‐2′,7′‐dichlorodihydrofluorescein diacetate (DCFDA). DCFDA fluoresence was found to be increased in a dose‐dependent manner when astrocytes were exposed to 1, 5, and 10 mM NH4Cl. This phenomenon was transitory; it peaked at 2.5 min after exposure and declined subsequently. By 2 hr after treatment, DCFDA fluorescence was below control level. Addition of catalase or superoxide dismutase to 5 mM NH4Cl‐treated astrocytes reduced free radical formation. Pretreatment with 3 mM methionine sulfoximine, an inhibitor of glutamine synthetase, also suppressed free radical formation by 5 mM NH4Cl. The results of this study suggest that elevated concentrations of ammonia induce the formation of free radicals in astrocytes and that this process is associated with the synthesis of glutamine. We propose that astrocyte‐derived free radicals may be responsible for some of the pathophysiological changes associated with hyperammonemic conditions. J. Neurosci. Res. 66:282–288, 2001. © 2001 Wiley‐Liss, Inc.
Identification and characterization of neuronal precursors and their progeny from human fetal tissue
Authors: Piper David R. , Mujtaba Tahmina , Keyoung Hansoo , Roy Neeta S. , Goldman Steven A. , Rao Mahendra S. , Lucero Mary T. 
Published: August 2002

AbstractWe have examined primary human neuronal precursors (HNPs) from 18–22‐week‐old fetuses. We showed that E‐NCAM/MAP2/β‐III tubulin‐immunoreactive neuronal precursors divide in vitro and could be induced to differentiate into mature neurons in 2 weeks. HNPs did not express nestin and differentiated slowly compared to rodent neuronal restricted precursors (NRPs, 5 days). Immunocytochemical and physiological analyses showed that HNPs could generate a heterogeneous population of neurons that expressed neurofilament‐associated protein and various neurotransmitters, neurotransmitter synthesizing enzymes, voltage‐gated ion channels, and ligand‐gated neurotransmitter receptors and could fire action potentials. Undifferentiated and differentiated HNPs did not coexpress glial markers. Only a subset of cells that expressed GFP under the control of the Tα1 tubulin promoter was E‐NCAM/β‐III tubulin‐immunoreactive, indicating nonexclusive overlap between these two HNP cell populations. Overall, HNPs resemble NRPs isolated from rodent tissue and appear to be a neuronal precursor population. J. Neurosci. Res. 66:356–368, 2001. © 2001 Wiley‐Liss, Inc.
Me and us: differential relationships among goal‐setting training, efficacy and effectiveness at the individual and team level
Authors: Gibson Cristina B. 
Published: August 2002

AbstractEfficacy‐effectiveness relationships were examined for individual nurses and nursing teams who were either trained or untrained in goal‐setting. At the individual level, positive direct relationships were demonstrated between self‐efficacy and effectiveness, between training and subsequent self‐efficacy, and between training and effectiveness. Initial self‐efficacy also moderated the training‐effectiveness relationship. Nurses low in initial self‐efficacy realized greater effectiveness gains from the training than did nurses high in initial self‐efficacy. At the team level, group efficacy was related to effectiveness, and training was related to subsequent group efficacy, but training was not related to effectiveness, and there were no moderation effects for initial group efficacy. Collective cognition and behavioral plasticity are potential explanations for different effects at the individual and team level and avenues for theory development and future research. Copyright © 2001 John Wiley & Sons, Ltd.
Re‐thinking burnout
Authors: Densten Iain L. 
Published: August 2002

AbstractThe conceptualization and psychometric properties of the Maslach Burnout Inventory (Maslach and Jackson, 1981) were examined by this study. A new structure of five burnout factors was identified using a sample of 480 Australian law enforcement managers. An examination of each item, along with single and confirmatory factor analyses supported both emotional exhaustion and the lack of personal accomplishment factors splitting into two factors while depersonalization remained a single factor. The new five‐factor structure incorporates psychological and somatic strain aspects of emotional exhaustion, and two aspects of the lack of personal accomplishment, namely self and others. This expanded factor structure clarifies the multi‐dimensional nature of the MBI. Further research directions are discussed. Copyright © 2001 John Wiley & Sons, Ltd.
The good soldier: who is s(he)?
Authors: Kidder Deborah L. , Parks Judi McLean 
Published: August 2002

AbstractThis paper examines how perceptions of Organizational Citizenship Behaviors (OCBs) are affected by socially constructed gender roles. We argue that gender roles are important for the perception, categorization, and consequences of OCBs. We suggest that the dimensions of OCBs (altruism, courtesy, sportsmanship, and civic virtue) are related to gender stereotypes. Combining social identity theory with gender role theory suggests that the ‘gender’ of these behaviors, the job, the job incumbent, and the gender identity of the observer interact, potentially broaden the breadth of requisite job behaviors defined as either in‐ or extra‐role. Implications are discussed. Copyright © 2001 John Wiley & Sons, Ltd.
Multi‐wave, multi‐variable models of job insecurity: applying different scales in studying the stability of job insecurity
Authors: Mauno Saija , Leskinen Esko , Kinnunen Ulla 
Published: August 2002

AbstractThe study had two specific targets: first, to examine the stability of job insecurity by utilizing three‐year longitudinal data (n = 109) collected in Finland and, second, to clarify psychometric properties of four job insecurity scales, i.e., the global scale, the importance scale, the probability scale and the powerlessness scale. The study was carried out by means of questionnaires, which were answered on three occasions. Analyses were conducted using multi‐wave, multi‐variable models which were estimated and tested via the LISREL program. Generally, the results showed that job insecurity remained relatively stable during the follow‐up period, although there were some variations in the stability as well as in the psychometric properties of the four job insecurity scales examined. More specifically, three of the scales studied showed good psychometric properties, whereas the probability scale could not be estimated longitudinally. Furthermore, working organization and time had effects on the level of job insecurity measured via the different scales. Copyright © 2001 John Wiley & Sons, Ltd.
Reflections on shared cognition
Authors: Cannon‐Bowers Janis A. , Salas Eduardo 
Published: August 2002

AbstractThe purpose of this paper is to highlight several fundamental questions that remain regarding shared cognition: (1) What must be ‘shared’? (2) What does ‘shared’ mean? (3) How should ‘shared’ be measured? and (4) What outcomes do we expect shared cognition to affect? A general and integrative description of these questions is provided. In addition, the value of shared cognition is discussed along with recommendations for future research. Copyright © 2001 John Wiley & Sons, Ltd.
Trends in extreme daily rainfall and temperature in Southeast Asia and the South Pacific: 1961–1998
Authors: Manton M.J. , Della‐Marta P.M. , Haylock M.R. , Hennessy K.J. , Nicholls N. , Chambers L.E. , Collins D.A. , Daw G. , Finet A. , Gunawan D. , Inape K. , Isobe H. , Kestin T.S. , Lefale P. , Leyu C.H. , Lwin T. , Maitrepierre L. , Ouprasitwong N. , Page C.M. , Pahalad J. , Plummer N. , Salinger M.J. , Suppiah R. , Tran V.L. , Trewin B. , Tibig I. , Yee D. 
Published: August 2002

AbstractTrends in extreme daily temperature and rainfall have been analysed from 1961 to 1998 for Southeast Asia and the South Pacific. This 38‐year period was chosen to optimize data availability across the region. Using high‐quality data from 91 stations in 15 countries, significant increases were detected in the annual number of hot days and warm nights, with significant decreases in the annual number of cool days and cold nights. These trends in extreme temperatures showed considerable consistency across the region. Extreme rainfall trends were generally less spatially coherent than were those for extreme temperature. The number of rain days (with at least 2 mm of rain) has decreased significantly throughout Southeast Asia and the western and central South Pacific, but increased in the north of French Polynesia, in Fiji, and at some stations in Australia. The proportion of annual rainfall from extreme events has increased at a majority of stations. The frequency of extreme rainfall events has declined at most stations (but not significantly), although significant increases were detected in French Polynesia. Trends in the average intensity of the wettest rainfall events each year were generally weak and not significant. Copyright © 2001 Royal Meteorological Society