bluuebunny/crossref_metadata_2025 huggingface dataset:
Imaging FRET standards by steady‐state fluorescence and lifetime methods
Authors: Domingo Beatriz , Sabariegos Rosario , Picazo Fernando , Llopis Juan
Published: August 2007

Imaging fluorescence resonance energy transfer (FRET) between molecules labeled with fluorescent proteins is emerging as a powerful tool to study changes in ions, ligands, and molecular interactions in their physiological cellular environment. Different methods use either steady‐state fluorescence properties or lifetime to quantify the FRET rate. In addition, some provide the absolute FRET efficiency whereas others are simply a relative index very much influenced by the actual settings and instrumentation used, which makes the interpretation of a given FRET rate very difficult. The use and exchange of FRET standards in laboratories using these techniques would help to overcome this drawback. We report here the construction and systematic evaluation of FRET standard probes of varying FRET efficiencies. The standards for intramolecular FRET were protein fusions of the cyan and yellow variants of A. victoria green fluorescent protein (ECFP and citrine) joined by short linkers or larger protein spacers, or ECFP tagged with a tetracysteine motif and labeled with the biarsenical fluorochrome, FlAsH. Negative and positive controls of intermolecular FRET were also used. We compared these FRET standards with up to four FRET quantification methods: ratioing of acceptor to donor emission, donor intensity recovery upon acceptor photobleach, sensitized emission after spectral unmixing of raw images, and fluorescence lifetime imaging (FLIM). The latter was obtained with a frequency‐domain setup able to provide high quality lifetime images in less than a second, and is thus very well suited for live cell studies. The FRET rates or indexes of the standards were in good agreement regardless of the method used. For the CFP‐tetraCys/FlAsH pair, the rate calculated from CFP quenching was faster than that obtained by FLIM. Microsc. Res. Tech., 2007. © 2007 Wiley‐Liss, Inc.
Age‐related changes of NADPH‐diaphorase‐positive neurons in the rat inferior colliculus and auditory cortex
Authors: Sánchez‐Zuriaga Daniel , Martí‐Gutiérrez Nuria , De La Cruz Maria Ángeles Pérez , Peris‐Sanchis Maria Rosa
Published: August 2007

Nitric oxide (NO) has been implied in age‐related changes of the central nervous system (CNS) and the central auditory pathway. The present study was conducted to investigate whether the number of NO‐producing cells and their morphometric characteristics in the inferior colliculus (IC) and the auditory cortex (AC) are changed with the increasing age of the subjects. IC and AC sections of adult and senile Wistar rats were studied using the histochemical detection of NADPH‐diaphorase activity (NADPH‐d), a marker for neurons containing nitric oxide synthase (NOS). Our results showed a decreased area of the somas of NADPH‐d‐positive neurons in the dorsal cortex (DC) of the IC and a diffuse loss of NADPH‐d‐positive neurons in the senile IC and primary cortical auditory area (Te1). However, an increased number of NO‐producing cells have been shown by other authors in different parts of the ageing auditory pathway and CNS. It seems that age‐related changes in NADPH‐d‐positive cells may follow a region‐specific route. These changes may be related to hearing impairments with increasing age. Microsc. Res. Tech., 2007. © 2007 Wiley‐Liss, Inc.
An improved confocal FRAP technique for the measurement of long‐term actin dynamics in individual stress fibers
Authors: Campbell J.J. , Knight M.M.
Published: August 2007

The present study describes an improved fluorescent recovery after photobleaching (FRAP) technique, which has been successfully used to quantify actin dynamics within individual fibers. Chondrocytes were transfected with an eGFP‐actin plasmid and cultured on glass coverslips. In cells expressing eGFP‐actin, confocal microscopy was used to bleach 3 × 1 μm regions accurately positioned along individual stress fibers. The subsequent fluorescent recovery over a 10‐min imaging period was assessed from a series of intensity profiles, positioned along the length of the stress fibers and spanning the bleach region. From these profiles, the normalized fluorescent intensity values were plotted against time. In this way, the technique provided sufficient spatial precision to describe the long‐term behavior within individual stress fibers while accounting for the inherent movement. An identical procedure was used to examine FRAP for eGFP‐actin within the interfiber region. The FRAP curves for stress fibers were accurately modeled by two phase exponentials which indicated only partial recovery with a mobile fraction of 46%. This suggests that some of the F‐actin molecules were in a tightly bound configuration with negligible turnover. The interfiber region exhibited similar two phase exponential FRAP with a mobile fraction of 68%. This partial recovery may be due to the presence, within the interfiber region, of both G‐actin and fine F‐actin fibers beneath the resolution of the confocal microscope. In conclusion, the present FRAP methodology overcomes many of the limitations of previous studies in order to provide new data describing long‐term actin dynamics within individual stress fibers. Microsc. Res. Tech., 2007. © 2007 Wiley‐Liss, Inc.
Evaluation of top, angle, and side cleaned FIB samples for TEM analysis
Authors: Montoya Eduardo , Bals Sara , Rossell Marta D. , Schryvers Dominique , Van Tendeloo Gustaaf
Published: August 2007

TEM specimens of a LaAlO3/SrTiO3 multilayer are prepared by FIB with internal lift out. Using a Ga+1 beam of 5 kV, a final cleaning step yielding top, top‐angle, side, and bottom‐angle cleaning is performed. Different cleaning procedures, which can be easily implemented in a dual beam FIB system, are described and compared; all cleaning types produce thin lamellae, useful for HRTEM and HAADF‐STEM work up to atomic resolution. However, the top cleaned lamellae are strongly affected by the curtain effect. Top‐angle cleaned specimens show an amorphous layer of around 5 nm at the specimen surfaces, due to damage and redeposition. Furthermore, it is observed that the LaAlO3 layers are preferentially destroyed and transformed into amorphous material, during the thinning process. Microsc. Res. Tech., 2007. © 2007 Wiley‐Liss, Inc.
Tradeoffs between somatic and gonadal investments during development in the African clawed frog (Xenopus laevis)
Authors: McCoy Krista A. , McCoy Michael W. , Amick Alison , Guillette Louis J. , St. Mary Colette M.
Published: August 2007

Tradeoffs between time to and size at metamorphosis occur in many organisms with complex life histories. The ability to accelerate metamorphosis can increase survival to the next life stage, but the resulting smaller size at metamorphosis is often associated with lower post‐metamorphic survival or reduced fecundity of adults. Reduced fecundity is thought to be because of reduced energy reserves, longer time to maturity, or reduced capacity to carry eggs or compete for mates. This pattern could also be explained by a shift in allocation to somatic growth that further retards the growth or development of reproductive tissues. The main goal of this study was to determine if the relationship between growth and development of somatic and gonadal tissues depends on environmental conditions. We address this question through two experiments in which we quantify the development and growth of the body and gonads of Xenopus laevis reared in different resource environments. First, tadpoles were reared communally and development and growth were evaluated over time. Restricted food reduced somatic and gonadal growth rate, but did not affect the developmental rate of either tissue type. Second, tadpoles were reared individually and evaluated at metamorphosis. Restricted food reduced somatic development and growth, but only influenced size, and not developmental stage of testes at metamorphosis. This work demonstrates that environmental conditions influence tradeoffs between growth and development of somatic and gonadal tissues, apparently in a sex‐specific manner. These tradeoffs may contribute to phenotypic correlations between small size and reduced fitness J. Exp. Zool. 307A:637–646, 2007. © 2007 Wiley‐Liss, Inc.
Tfap2 transcription factors in zebrafish neural crest development and ectodermal evolution
Authors: Hoffman Trevor L. , Javier Anna L. , Campeau Shelley A. , Knight Robert D. , Schilling Thomas F.
Published: August 2007

Transcription factor AP2 (Tfap2) genes play essential roles in development of the epidermis and migratory cells of the neural crest (NC) in vertebrate embryos. These transcriptional activators are among the earliest genes expressed in the ectoderm and specify fates within the epidermis/crest through both direct and indirect mechanisms. The Tfap2 family arose from a single ancestral gene in a chordate ancestor that underwent gene duplication to give up to five family members in living vertebrates. This coincided with the acquisition of important roles in NC development by Tfap2 genes suggesting that this gene family was important in ectodermal evolution and possibly in the origin of NC. Here, we show that a zebrafish tfap2c is expressed in the nonneural ectoderm during early development and functions redundantly with tfap2a in NC specification. In zebrafish embryos depleted of both tfap2a and tfap2c, NC cells are virtually eliminated. Cell transplantation experiments indicate that tfap2c functions cell‐autonomously in NC specification. Cells of the enveloping layer, which forms a temporary skin layer surrounding the ectoderm, also fail to differentiate or to express appropriate keratins in tfap2c deficient embryos. The role of Tfap2 genes in epidermal and NC development is considered here in the broader context of ectodermal evolution. Distinct, tissue‐specific functions for Tfap2 genes in different vertebrates may reflect subfunctionalisation of an ancestral gene that consequently led to the gain of novel roles for different subfamily members in patterning the epidermis and NC. J. Exp. Zool. (Mol. Dev. Evol.) 308B:679–691, 2007. © 2007 Wiley‐Liss, Inc.
On the search for glycated lipoprotein ApoA‐I in the plasma of diabetic and nephropathic patients
Authors: Lapolla Annunziata , Brioschi Maura , Banfi Cristina , Tremoli Elena , Bonfante Luciana , Cristoni Simone , Seraglia Roberta , Traldi Pietro
Published: August 2007

The analysis of plasma samples from healthy, diabetic and nephropathic subjects was carried out by 2D gel electrophoresis. This approach shows clear differences among the three classes of subjects. In the case of diabetic and nephropathic patients intense spots appear. Their enzymatic digestion followed by matrix assisted laser desorption ionization/mass spectrometry (MALDI/MS) analysis shows that an overexpression of unglycated and glycated ApoA‐I is present in both pathological states. Interestingly, this trend is also observed for the retinol‐binding protein (RBP). The data obtained can be relevant to assess possible risks associated either with the glycation level of ApoA‐I or with the overexpression of RBP. In fact, in the former case possibly a different functionality of the glycated protein is to be expected, reflecting a different efficiency in cholesterol transport. In the latter case, the increase of RBP level can be related to the overweight of the diabetic subjects under investigation: it is known that obesity leads to RBP overexpression. In the case of nephropathic patients, the RBP level increases in parallel with serum creatinin. Copyright © 2007 John Wiley & Sons, Ltd.
The myelin‐associated glycoprotein inhibitor BENZ induces outgrowth and survival of rat dorsal root ganglion cell cultures
Authors: Nowicki Marcin , Kosacka Joanna , Brossmer Reinhard , Spanel‐Borowski Katharina , Borlak Jürgen
Published: August 2007

The novel myelin‐associated glycoprotein (MAG) inhibitor BENZ binds to the N‐acetylneuraminic acid (Neu5Ac) portion of the N‐terminal Ig‐like domain of MAG. Treatment of rat dorsal root ganglion (DRG) cell cultures with BENZ‐induced outgrowth of neurofilament 200–positive neurites improved survival of neurons and increased the number of GFAP‐positive cells, as determined by fluorescence and confocal laser microscopy and by Western immunoblotting. Furthermore, treatment of DRG cell cultures with BENZ repressed gene and protein expression of the small GTPase RhoA but induced expression of Rho GTP–activating proteins 5 and 24, likely to counteract protein kinase A activity. Specifically, expression of inhibitors of neurite outgrowth, for example, Rock2 and PAK4, was repressed, but cofilin 1, a promoter of axonal growth, was induced. We propose that the MAG inhibitor BENZ abrogates the RhoA–ROCK–cofilin pathway to promote neurite outgrowth. Our findings require confirmation by in vivo animal studies. © 2007 Wiley‐Liss, Inc.
Structure, properties, and functions of the human small heat‐shock protein HSP22 (HspB8, H11, E2IG1): A critical review
Authors: Shemetov Anton A. , Seit‐Nebi Alim S. , Gusev Nikolai B.
Published: August 2007

The recently described human HSP22 belongs to the superfamily of small heat‐shock proteins containing a conservative α‐crystallin domain. HSP22 seems to be involved in regulation of cell proliferation, cardiac hypertrophy, apoptosis, and carcinogenesis, and expression of point mutants of HSP22 correlates with development of different neuromuscular diseases. Therefore, an investigation of the structure and properties of HSP22 is desirable for understanding its multiple functions. HSP22 seems to belong to the group of so‐called intrinsically disordered proteins and possesses a highly flexible structure. HSP22 tends to form small‐molecular‐mass oligomers and interacts with biological membranes and many different proteins, among them glycolytic enzymes and different protein kinases. HSP22 possesses chaperonelike activity and prevents aggregation of denatured proteins both in vitro and in vivo. Depending on the cell type and its expression, HSP22 might have either pro‐ or anti‐apoptotic effects. Chaperonelike activity seems to be important for antiapoptotic effects, whereas interaction with and regulation of certain protein kinases might be important for the proapoptotic effects of HSP22. Expression of K141N or K141E mutants of HSP22 correlates with development of distal hereditary motor neuropathy and/or Charcot‐Marie‐Tooth disease. These mutations destabilize the structure of HSP22, affect its interaction with other small heat‐shock proteins, and decrease its chaperonelike activity. HSP22 decreases or prevents aggregation of Huntingtin fragments and amyloid‐β peptide 1–40 of the Dutch type. Thus, HSP22 seems to play an important role in the nervous system, and further investigations are needed to understand the molecular mechanisms of its functioning. © 2007 Wiley‐Liss, Inc.
Nuclear magnetic resonance studies of energy metabolism and glutamine shunt in hepatic encephalopathy and hyperammonemia
Authors: Zwingmann Claudia
Published: August 2007

Hepatic encephalopathy (HE) in both acute and chronic liver failure is more likely a reversible functional disease rather than an irreversible pathological lesion of brain cells. Metabolic alterations underlie many of the mechanisms leading to HE. This paper summarizes in vivo and ex vivo 1H‐, 13C‐, and 15N‐nuclear magnetic resonance (NMR) spectroscopy data on patients and experimental models of HE. In vivo NMR spectroscopy provides a unique opportunity to study metabolic changes noninvasively in the brain in vivo, and to quantify various metabolites in localized brain areas, and ex vivo NMR permits the high‐resolution measurement of metabolites and the identification of different metabolic pathways. In vivo and ex vivo 1H‐NMR investigations consistently reveal severalfold increases in brain glutamine and concomitant decreases in myo‐inositol, an important osmolyte in astrocytes. An osmotic disturbance in these cells has long been suggested to be responsible for astrocyte swelling and brain edema. However, ex vivo 13C‐NMR studies have challenged the convention that glutamine accumulation is the major cause of brain edema in acute HE. They rather indicate a limited anaplerotic flux and capacity of astrocytes to detoxify ammonia by glutamine synthesis and emphasize distortions of energy and neurotransmitter metabolism. However, recent 15N‐NMR investigations have demonstrated that glutamine fluxes between neurons and astrocytes are affected by ammonia. Further NMR studies may provide novel insights into the relationship between brain edema and/or astrocyte pathology and changes in inter‐ and intracellular glutamine homeostasis, which may secondarily alter brain energy metabolism. © 2007 Wiley‐Liss, Inc.
Expression of an acyl‐CoA synthetase, lipidosin, in astrocytes of the murine brain and its up‐regulation during remyelination following cuprizone‐induced demyelination
Authors: Song Si‐Young , Kato Chieko , Adachi Eijiro , Moriya‐Sato Ayako , Inagawa‐Ogashiwa Masayo , Umeda Rieko , Hashimoto Naohiro
Published: August 2007

Lipidosin is an 80‐kDa protein with long‐chain acyl‐CoA synthetase activity expressed in the brain, adrenal gland, testis, and ovary, which are selectively damaged in X‐linked adrenoleukodystrophy (X‐ALD). Western blot analysis of the cerebrum and cerebellum revealed a gradual increase in the expression of lipidosin postnatally. Light microscopic immunohistochemistry using a panel of specific monoclonal antibodies showed that the lipidosin‐immunopositive cells were ubiquitously distributed in the brain and were denser in the gray matter than in the white matter. Lipidosin immunoreactivity was colocalized with GFAP immunoreactivity but not with ubiquitin C‐terminal hydrolase 1 (= PGP9.5) immunoreactivity, a neuronal marker, and lipidosin‐producing cells detected by an antisense probe specific for lipidosin mRNA were also GFAP immunopositive. These data together with Western blot analysis of primary cultured astrocytes indicate that lipidosin is expressed in astrocytes. Immunoelectron microscopic analysis revealed that lipidosin immunoreactivity was widely distributed from perivascular endfeet to perisynaptic processes without being limited to peroxisomes. Lipidosin immunoreactivity was greatly increased in astrocytes in the area of remyelination following experimental demyelination induced by the administration of cuprizone to mice. These data suggest that lipidosin was involved in fatty acid metabolism during reconstruction of the myelin sheath. © 2007 Wiley‐Liss, Inc.
Bone morphogenetic proteins 4, 6, and 7 are up‐regulated in mouse spinal cord during experimental autoimmune encephalomyelitis
Authors: Ara Jahan , See Jill , Mamontov Polina , Hahn Ashleigh , Bannerman Peter , Pleasure David , Grinspan Judith B.
Published: August 2007

Although spontaneous remyelination occurs in multiple sclerosis (MS), the extent of myelin repair is often inadequate to restore normal function. Oligodendrocyte precursors remaining in nonremyelinating MS plaques may be restricted by an inhibitory signal. Bone morphogenetic proteins (BMPs) have been implicated as repressors of oligodendrocyte development and inducers of astrogliogenesis. We hypothesized that BMPs are up‐regulated in MS lesions and play a role in demyelination and astrogliosis. We examined expression of BMPs in an animal model of MS, chronic experimental autoimmune encephalomyelitis (EAE) induced by the myelin oligodendrocyte glycoprotein (MOG) peptide in C57BL/6 mice. By 14 days postimmunization, compared to those of control mice, the lumbar spinal cords of MOG‐peptide EAE mice demonstrated prominent astrogliosis, infiltration of inflammatory cells, and disrupted expression of myelin proteins. Quantitative RT‐PCR showed that expression of BMP4, BMP6, and BMP7 mRNA increased 2‐ to 4‐fold in the lumbar spinal cords of animals with symptomatic EAE versus in vehicle‐treated and untreated controls on days 14, 21, and 42 postimmunization. BMP2 mRNA expression was not altered. BMP4 mRNA was much more abundant in the spinal cords of all animals than was mRNA encoding BMP2, BMP6, and BMP7. Immunoblot analysis confirmed the increased expression of BMP4 in the EAE animals. Immunohistochemistry revealed increased BMP4 immunoreactivity in areas of inflammation in MOG‐peptide EAE animals. BMP4 labeling was mostly limited to macrophages but was sometimes associated with astrocytes and oligodendrocytes. These results indicate that members of the BMP family are differentially expressed in adult spinal cord and are up‐regulated during EAE. © 2007 Wiley‐Liss, Inc.
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

17‐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

In 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

Programmed 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

We 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

Emerging 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

Excitotoxicity 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

5‐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

Myricetin (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

The 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

This 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

One 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

Over 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

Cities, 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

SC 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

Sir 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

Studies 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.
Capital One banks on Six Sigma for strategy execution and culture transformation
Authors: Immaneni Aravind , McCombs Allen , Cheatham Gus , Andrews Ron
Published: August 2007

When a major shift in strategy propelled Capital One Direct Banking business in a new direction, the organization—arming itself with Six Sigma expertise and capabilities—set out to change its management model, redesign its major business processes, and nurture a culture centered around customer focus and continuous improvement. Three years later, the associates have embraced this new culture of customer focus and a commitment to continuous improvement—all with enviable results to the bottom line. The Direct Banking business has been recognized both internally within Capital One and by external organizations with numerous awards for accomplishing this impressive cultural transformation. © 2007 Wiley Periodicals, Inc.
Coaching leaders to be coaches at EDS
Authors: Moran Jane
Published: August 2007

As part of EDS's recent corporate transformation, a two‐pronged coaching initiative is helping leaders think more innovatively, take inspired action, and be more accountable. A brain‐based approach provides a coaching framework for professional delivery of one‐on‐one coaching and for equipping all leaders with the skills to coach others in the organization. A coach or leader uses the four‐step methodology to move an individual through the mental stages necessary to alter brain patterns in a way that leads to sustainable behavior change. Coaching skills training is being delivered to EDS leaders around the globe through interactive teleconference sessions. © 2007 Wiley Periodicals, Inc.
FTIR and FT‐Raman spectra and density functional computations of the vibrational spectra, molecular geometry and atomic charges of the biomolecule: 5‐bromouracil
Authors: Rastogi V. K. , Palafox M. A. , Mittal L. , Peica N. , Kiefer W. , Lang K. , Ojha S. P.
Published: August 2007

FTIR and FT‐Raman spectra of 5‐bromouracil in the powder form were recorded in the region 400–4000 cm−1 and 50–4000 cm−1, respectively. The observed wavenumbers were analysed and assigned to different normal modes of vibration of the molecule. Quantum chemical calculations were performed to support the assignments of the observed wavenumbers. The performance of the B3LYP hybrid density functional (DFT) method was compared with other methods. With the 6–31 G** and 6–311 + G(2d,p) basis sets, the calculated geometry, dipole moments and harmonic vibrations were determined. A comparison with the uracil molecule was made, and specific scale factors were deduced and employed in the predicted wavenumbers of 5‐bromouracil. The total atomic charges and thermodynamic parameters were calculated, and are discussed briefly. Structure and harmonic vibrations of 5‐bromouracil were also calculated in the presence of water within a simple model with one molecule. It is observed that the bromine atom at position 5 exhibits smaller inductive effects than the fluorine atom, producing a small distortion of the electrostatic potential around the ring and a reduction of the molecular dipole moment. Copyright © 2007 John Wiley & Sons, Ltd.