bluuebunny/crossref_metadata_2025_split huggingface dataset:
Axogenic effect of estrogen in male rat hypothalamic neurons involves Ca2+, protein kinase C, and extracellular signal‐regulated kinase signaling
Authors: Gorosito S.V. , Cambiasso M.J. 
Published: August 2007

Abstract17‐β‐Estradiol (E2) stimulates the growth of axons in male‐derived hypothalamic neurons in vitro. This effect is not exerted through the classical intracellular estrogen receptor (ER) but depends on a membrane mechanism involving TrkB. In the present study, we investigate the intracellular signaling cascade that mediates the axogenic effect of E2. Treatment with an intracellular Ca2+ chelator, a Ca2+‐dependent protein kinase C (PKC) inhibitor, or two specific inhibitors of extracellular signal‐regulated kinases (ERK) mitogen‐activated protein kinases (MAPK) completely inhibited the E2‐induced axogenesis. E2 and the membrane‐impermeant construct E2BSA rapidly induced phosphorylation of ERK, which was blocked by the specific inhibitor of the ERK pathway UO126 but not by the ER antagonist ICI 182,780. Decrease of intracellular free Ca2+ or disruption of PKC activation by Ro 32‐0432 attenuated ERK activation, indicating the confluence of signals in the MAPK pathway. Subcellular analysis of ERK demonstrated that the phospho‐ERK signal is augmented in the nucleus after 15 min of E2 stimulation. We have also shown that E2 increased phosphorylation of CREB via ERK signaling. In summary, this study demonstrates that E2, probably via a membrane‐associated receptor, induces axonal growth by activating CREB phosphorylation through ERK signaling by a mechanism involving Ca2+ and PKC activation. © 2007 Wiley‐Liss, Inc.
Vertebrate rod photoreceptors express both BK and IK calcium‐activated potassium channels, but only BK channels are involved in receptor potential regulation
Authors: Pelucchi Bruna , Grimaldi Annalisa , Moriondo Andrea 
Published: August 2007

AbstractIn salamander rods, Ca2+‐activated K+ current (IKCa) provides an effective “clamp” of the dark membrane potential to its normal resting level. By a combination of electrophysiological, pharmacological, and immunohistochemical approaches, we show that salamander rods functionally express large‐conductance Ca2+‐ and voltage‐dependent potassium (BK) channel and intermediate‐conductance Ca2+‐dependent potassium (IK) channel, but not small‐conductance Ca2+‐dependent potassium channel (SK) subtypes. Application of 100 nM iberiotoxin and 100 nM clotrimazole reduced net IKCa to 36% and 63%, respectively, whereas the current was unaffected by application of 1 μM apamin. Consistently, anti‐ SK1, ‐SK2, and ‐SK3 antibodies were unable to stain rod photoreceptors, whereas both anti‐BK and ‐SK4/ IK1 antibodies heavily stained the ellipsoid region of the inner segments of the rods. Moreover, by using current‐clamp experiments, it was clearly seen that the strong clamping effect of the total IKCa was lost when IbTx, but not CLTZ, was applied to the bath. This behavior strongly suggests that of BK and IK channels, only the former are responsible for the clamping effect on the photoreceptor membrane potential. © 2007 Wiley‐Liss, Inc.
Inducible cAMP early repressor (ICER)‐evoked delayed neuronal death in the organotypic hippocampal culture
Authors: Mioduszewska Barbara , Jaworski Jacek , Szklarczyk Arek W. , Klejman Agata , Kaczmarek Leszek 
Published: August 2007

AbstractProgrammed cell death involving gene regulation and de novo protein synthesis is a major component of both normal development and a number of disease conditions. Hence, knowledge of its mechanisms, especially transcription factors, that regulate expression of the genes involved in neurodegenerative disorders is of great importance. cAMP‐responsive element–binding protein (CREB) has repeatedly been implicated in the neuronal survival. In the present study we showed that inducible cAMP early repressor (ICER), an endogenous CREB antagonist, is expressed during both excitotoxic and spontaneous neuronal cell death in organotypic hippocampal slice cultures in vitro. Furthermore, overexpression of ICER via an adenoviral vector evoked neuronal cell loss in such cultures. The time course of ICER‐dependent cell death was hippocampal subdivision specific, with dentate gyrus neurons dying mostly 3–7 days after the adenovector infection, followed by CA3, where neuronal death peaked after 7 days, and then CA1, where most neuronal death occurred after 7–14 days. These results underscore the usefulness of the organotypic cultures for studies of neurodegeneration and point to neuronal loss having a multifaceted nature in a complex cellular environment. © 2007 Wiley‐Liss, Inc.
Caspase inhibitor facilitates recovery of hearing by protecting the cochlear lateral wall from acute cochlear mitochondrial dysfunction
Authors: Mizutari Kunio , Matsunaga Tatsuo , Kamiya Kazusaku , Fujinami Yoshiaki , Fujii Masato , Ogawa Kaoru 
Published: August 2007

AbstractWe recently showed that acute energy failure in the rat cochlea induced by local administration of the mitochondrial toxin 3‐nitropropionic acid (3‐NP) causes hearing loss mainly due to degeneration of cochlear lateral‐wall fibrocytes. In the present study, we analyzed the effect of the pan‐caspase inhibitor z‐Val‐Ala‐Asp(Ome)‐fluoromethylketone (Z‐VAD‐FMK) on 3‐NP‐induced hearing loss in a model showing temporary threshold shifts at low frequencies and permanent threshold shifts at high frequencies. The model rats received an intraperitoneal injection of either Z‐VAD‐FMK or vehicle for 3 days starting 1 day prior to 3‐NP treatment. One day after the administration of 3‐NP, the auditory brain‐stem response (ABR) threshold at 20 kHz was elevated to 70 dB in the Z‐VAD‐FMK group and to 85 dB in controls. The Z‐VAD‐FMK group completely recovered to the preoperative level within 14 days, whereas in the controls, the ABR threshold remained elevated at 50 dB even 28 days after the administration of 3‐NP. Treatment with Z‐VAD‐FMK also improved recovery of hearing at 8 kHz but did not change recovery at 40 kHz. Histological examination demonstrated that treatment with Z‐VAD‐FMK inhibited progressive degeneration of the lateral‐wall fibrocytes in the cochlear basal turn, as well as apoptosis of these fibrocytes. These results clearly indicate that caspase‐dependent apoptosis of fibrocytes in the cochlear lateral wall plays an important role in hearing loss in the present animal model. Moreover, the results of the present study suggest that systemic administration of a caspase inhibitor may be an effective therapy for sensorineural hearing loss caused by acute energy failure such as that observed in cochlear ischemia. © 2007 Wiley‐Liss, Inc.
Maternal embryonic leucine zipper kinase is a key regulator of the proliferation of malignant brain tumors, including brain tumor stem cells
Authors: Nakano Ichiro , Masterman‐Smith Michael , Saigusa Kuniyasu , Paucar Andres A. , Horvath Steve , Shoemaker Lorelei , Watanabe Momoko , Negro Alejandra , Bajpai Ruchi , Howes Amy , Lelievre Vincent , Waschek James A. , Lazareff Jorge A. , Freije William A. , Liau Linda M. , Gilbertson Richard J. , Cloughesy Timothy F. , Geschwind Daniel H. , Nelson Stanley F. , Mischel Paul S. , Terskikh Alexey V. , Kornblum Harley I. 
Published: August 2007

AbstractEmerging evidence suggests that neural stem cells and brain tumors regulate their proliferation via similar pathways. In a previous study, we demonstrated that maternal embryonic leucine zipper kinase (Melk) is highly expressed in murine neural stem cells and regulates their proliferation. Here we describe how MELK expression is correlated with pathologic grade of brain tumors, and its expression levels are significantly correlated with shorter survival, particularly in younger glioblastoma patients. In normal human astrocytes, MELK is only faintly expressed, and MELK knockdown does not significantly influence their growth, whereas Ras and Akt overexpressing astrocytes have up‐regulated MELK expression, and the effect of MELK knockdown is more prominent in these transformed astrocytes. In primary cultures from human glioblastoma and medulloblastoma, MELK knockdown by siRNA results in inhibition of the proliferation and survival of these tumors. Furthermore, we show that MELK siRNA dramatically inhibits proliferation and, to some extent, survival of stem cells isolated from glioblastoma in vitro. These results demonstrate a critical role for MELK in the proliferation of brain tumors, including their stem cells, and suggest that MELK may be a compelling molecular target for treatment of high‐grade brain tumors. © 2007 Wiley‐Liss, Inc.
ERK1 plays a critical protective role against N‐methyl‐D‐aspartate‐induced retinal injury
Authors: Nakazawa Toru , Shimura Masahiko , Ryu Morin , Nishida Kohji , Pagès Gilles , Pouysségur Jacques , Endo Shogo 
Published: August 2007

AbstractExcitotoxicity has been implicated in several ischemic diseases of the retina, including retinal vessel occlusion and diabetic retinopathy. Glutamate signaling mediated through the N‐methyl‐D‐aspartate (NMDA) receptor contributes to ischemic cell death. The NMDA receptor antagonists MK‐801 and memantine have substantial neuroprotective effects in experimental retinal disease models, but the mechanisms by which NMDA receptor activity leads to cell death is not clear. Here we describe a previously unknown role for retinal glial cells in NMDA‐induced retinal injury that involves the activation of ERK1/2. Within 1 hr after injecting NMDA intravitreally, activation of ERK1/2 and c‐Fos induction were observed in retinal Müller cells. The roles of activated ERK1/2 in neuronal damage were examined using ERK1 gene deficient mice (homozygous ERK1−/− mice). NMDA‐induced ERK1/2 activation in retina was significantly suppressed in ERK1−/− mice, and these mice had significantly higher numbers of TUNEL‐positive retinal cells than wild‐type mice 24 hr after NMDA injection. These data suggest that, during NMDA injury, Müller cells are activated and play a protective role against NMDA‐induced retinal cell death. ERK1 appears to play a major role in this process. These new findings on retinal glial cell response during NMDA injury offer an important new therapeutic target for preventing many retinal disorders associated with excitotoxicity. © 2007 Wiley‐Liss, Inc.
5‐hydroxyoxindole, an indole metabolite, is present at high concentrations in brain
Authors: Crumeyrolle‐Arias Michèle , Tournaire Marie‐Claude , Rabot Sylvie , Malpaux Benoît , Thiéry Jean‐Claude 
Published: August 2007

Abstract5‐Hydroxyoxindole has been identified as a urinary metabolite of indole, which is produced from tryptophane via the tryptophanase activity of gut bacteria. We have demonstrated recently that 5‐hydroxyoxindole is an endogenous compound in blood and tissues of mammals, including humans. To date, 5‐hydroxyoxindole's role is unknown. The aim of this study was to compare 5‐hydroxyoxindole levels in plasma and cerebrospinal fluid (CSF) during day‐night and seasonal changes, as a common approach to pilot physiological characterization of any compound. Simultaneous blood and CSF sampling was performed in the ewe, because its size allows collection in quantities suitable for 5‐hydroxyoxindole assay (HPLC‐ED) in awake animals, without obvious physiological or behavioral disturbance. 5‐Hydroxyoxindole concentration was quite stable in plasma (2–6 nM range), whereas, in CSF, it displayed marked day‐night and photoperiodic variations (4–116 nM range). 5‐Hydroxyoxindole levels in CSF were twofold higher at night than during the day and at least one order of magnitude higher during the long compared with the short photoperiod. These day/night and photoperiodic variations persisted after pinealectomy, indicating that 5‐hydroxyoxindole rhythms in CSF are independent of melatonin formation. In conclusion, high levels of 5‐hydroxyoxindole in the CSF during long photoperiod and its daily modulation suggest physiological involvement of 5‐hydroxyoxindole in rhythmic adjustments in the brain, independently of the pineal gland. © 2007 Wiley‐Liss, Inc.
Multifunction of myricetin on Aβ: Neuroprotection via a conformational change of Aβ and reduction of Aβ via the interference of secretases
Authors: Shimmyo Yoshiari , Kihara Takeshi , Akaike Akinori , Niidome Tetsuhiro , Sugimoto Hachiro 
Published: August 2007

AbstractMyricetin (3,3′,4′,5,5′,7‐hexahydroxyflavone) is classified as a flavonoid with strong antioxidant effects. Oxidative stress plays a key role in various neurological diseases such as ischemia and Alzheimer's disease (AD). To elucidate whether myricetin could counter the progress of AD, we examined the effects of myricetin on neurotoxicity induced by β‐amyloid (Aβ), a component of senile plaques in the AD brain. We found that cultured rat primary cortical neurons treated for 48 hr with Aβ1–42 (1 μM) induced significant neuronal injury. Conformationally altered Aβ1–42 caused apoptotic changes, such as nuclear fragmentation, as shown by DAPI staining. Pre‐ and simultaneous administration of myricetin and Aβ1–42 reduced Aβ neurotoxicity in a concentration‐dependent manner. By using circular dichroism spectroscopy and a thioflavin T binding assay, we show that myricetin (10 μM, 48 hr) prevented structural changes in Aβ1–42 from a random coil to a β‐sheet‐rich structure. Aβ1–42‐induced apoptotic changes and caspase‐3 activation were reduced by myricetin treatment. Furthermore, we determined that administration of myricetin significantly decreased Aβ1–40 and Aβ1–42 levels in culture media. These effects were based on two mechanisms: the activation and up‐regulation of α‐secretase (ADAM10) protein levels as indicated by fluorescence resonance energy transfer (FRET) assay and immunoblot analysis and the direct binding and inhibition of β‐secretase (BACE‐1) indicated by cell‐free FRET assays. Evidently, myricetin has multiple functions to counter the progress of AD by the reduction of Aβ production and the detoxification of Aβ through a structural change. © 2007 Wiley‐Liss, Inc.
Moderating effects of political skill, perceived control, and job‐related self‐efficacy on the relationship between negative affectivity and physiological strain
Authors: Zellars Kelly L. , Perrewé Pamela L. , Rossi Ana M. , Tepper Bennett J. , Ferris Gerald R. 
Published: August 2007

AbstractThe present study examined whether employees high in negative affectivity (NA) are destined to experience strain at a higher level than those low in NA. We used data collected from 230 employees to investigate the moderating effects of political skill, as a form of interpersonal control, on the relationship between NA and physiological strain. As hypothesized, NA was positively related to physiological strain (i.e., facial muscle tension as measured by electromyography (EMG)), and political skill buffered this effect such that the relationship was weaker among employees who were higher in political skill. Tests of mediated moderation further suggested the means by which political skill moderates the NA/strain relationship; specifically, the results were consistent with the idea that perceived control and, in turn, job‐related efficacy explain the moderating effect of political skill. Strengths and limitations of the study, practical implications, and directions for future research are discussed. Copyright © 2007 John Wiley & Sons, Ltd.
Giving peace a chance: organizational leadership, empowerment, and peace
Authors: Spreitzer Gretchen 
Published: August 2007

AbstractThis paper provides an exploratory look at how the leadership practices of business organizations may foster more peaceful societies. I develop the logic for positive relationships between participative organizational leadership, employee empowerment, and peace. I offer several mechanisms to explain why these different manifestations of voice are likely to contribute to peaceful societies. I then draw on several cross‐national databases to provide a preliminary examination of the hypotheses. I find support for the hypotheses regarding the positive effects of participative leadership and employee empowerment in work organizations on peace. The paper concludes by discussing contributions of this research to the organizational studies literature and offers directions for future research. Copyright © 2007 John Wiley & Sons, Ltd.
Changes in European drought characteristics projected by the PRUDENCE regional climate models
Authors: Blenkinsop S. , Fowler H. J. 
Published: August 2007

AbstractOne of the key features of global climate change will be perturbations to the hydrological regime across Europe. To date, assessments of the impacts of future change have generally used results from only one climate model, thus underestimating the range of possible change projected by different climate models. Here, the skill of six regional climate models (RCMs) in reproducing the mean precipitation for the 1961–1990 period for six catchments across Europe is compared and their projections of changes in future precipitation are assessed. A simple drought index based on monthly precipitation anomalies is also described and used to assess the models. Considerable variation in model skill in reproducing monthly mean precipitation and drought statistics is observed, with model errors in the reproduction of drought events independent of those for the mean, suggesting that the models have difficulties in reproducing the observed persistence of low monthly rainfall totals. In broad terms, the models indicate decreases in summer and increases in winter precipitation across Europe. On the regional scales required for impacts analysis, considerable model uncertainty is demonstrated for future projections, particularly for drought frequency. Although increases in the frequency of long‐duration droughts are identified for catchments in southern Europe, the magnitude of this change is not certain. In contrast, for a catchment in northern England, such events are likely to become less frequent. For shorter‐duration droughts, future changes encompass the direction of change. For stakeholders in each of the regions, these changes and uncertainties pose different challenges for the management of water resources. For the scientific community, the challenge raised is how to incorporate this uncertainty in climate change projections in a way that allows those groups to make informed decisions based on model projections. It is suggested that probabilistic scenarios for specific hydrological impacts offer considerable potential to achieve this. Copyright © 2007 Royal Meteorological Society
Review of urban climate research in (sub)tropical regions
Authors: Roth Matthias 
Published: August 2007

AbstractOver the last 50 years the developing world, much of which is located in (sub)tropical regions, has seen a dramatic growth of its urban population associated with serious degradation of environmental quality. The total number of (sub)tropical urban climate studies, however; is still small (<20% of all urban climate studies). The available work is further biased towards descriptive studies rather than process work that seeks to indicate the physical climatology of (sub)tropical cities. The available results allow for a preliminary comparison with data from temperate latitudes. Urban heat island (UHI) intensities are generally lower compared to those of temperate cities with comparable population and show a seasonal variation with lower (higher) intensities during the wet (dry) season. (Sub)tropical population‐based relations may exist but insufficient appropriate data is available to confirm a logarithmic relationship or systematic differences between different climate types. The (sub)tropical energy balance studies are biased towards dry, clear sky conditions. The amount of net radiation dissipated by sensible heat during daytime is about 40% which is similar to values observed in (sub)urban areas of cities located in temperate climates. Energy partitioning is modulated by water availability and higher percentage of vegetation promotes latent heat flux at the expense of surface heat storage. The apparent strong influence of vegetation and water availability on the energy partitioning irrespective of the climate type, suggests vegetation to be an effective means to reduce heat storage uptake during daytime and hence has the potential to effectively mitigate the nocturnal heat island. It is important to ensure that the rapidly expanding cities of the developing world incorporate climatological concerns in their design to provide a better living and working environment for a large segment of the world's inhabitants. Copyright © 2007 Royal Meteorological Society
Cities as agents of global change
Authors: Mills Gerald 
Published: August 2007

AbstractCities, as places where human activities are concentrated, are frequently cited as the chief causes of, and solutions to, anthropogenic global change. In this article, I review the climatology literature that examines the relationship between cities and atmospheric changes at all scales. Despite the volume of literature on this theme, there is little overall coherence. In part, this is a result of the varying operational definitions of the city and the difficulty in obtaining pertinent information. Rather than attempt to provide a comprehensive review of the literature that focuses on cities and global change, this article categorises published research on the relationship between urban areas and climate changes at all scales into common themes. Copyright © 2007 Royal Meteorological Society
SC Johnson builds business at the base of the pyramid
Authors: Johnson Scott 
Published: August 2007

AbstractSC Johnson's sustainability strategy has led it to a unique partnership in Nairobi with a local community organization and groups of Kenyan youths. Together, they are pioneering a new business model, a product of field testing the Base of the Pyramid protocol, to create mutual value in Kenya's largest slums. The venture's first year produced many surprises, lessons, successes, and disappointments—and reinforced SC Johnson's commitment to drive social change and economic empowerment by partnering with communities at the bottom of the economic pyramid. © 2007 SC Johnson & Son, Inc.
Corporate social responsibility: A third way? An interview with Sir Geoffrey Owen
Authors: Vial Virginie 
Published: August 2007

AbstractSir Geoffrey Owen has been a Senior Fellow at the Institute of Management of the London School of Economics since 1996. From 1991 to 1996 he was Director of Business Policy in the Center for Economic Performance at the London School of Economics. He has held various senior positions in the industry sector and spent many years as Industry Correspondent as well as Deputy Editor for the Financial Times. In this interview, he answers 11 questions discussing the context in which corporate social responsibility is becoming a business concern. © 2007 Wiley Periodicals, Inc.
Work‐life balance: Expatriates reflect the international dimension
Authors: Shortland Sue , Cummins Siobhan 
Published: August 2007

AbstractStudies by ORC Worldwide have found that long hours, travel, and other work‐related factors intrude into personal lives and create stress for a significant portion of HR professionals and expatriates around the world. But while HR professionals believe work‐life balance policies have benefited their organization and themselves, expatriates believe quite the opposite. Given the cost of expatriate assignments and the potential for work‐life imbalance to erode employee commitment, organizations can do more to communicate and support work‐life practices outside their home country, and to better prepare the expatriate and family for life in their new location. © 2007 Wiley Periodicals, Inc.