bluuebunny/crossref_metadata_2025 huggingface dataset:
X‐Linked inhibitor of apoptosis protein is involved in mutant SOD1‐mediated neuronal degeneration
Authors: Ishigaki Shinsuke , Liang Yideng , Yamamoto Masahiko , Niwa Jun‐ichi , Ando Yoshio , Yoshihara Tsuyoshi , Takeuchi Hideyuki , Doyu Manabu , Sobue Gen
Published: March 2003

Mutations in the superoxide dismutase 1 (SOD1) gene cause the degeneration of motor neurons in familial amyotrophic lateral sclerosis (FALS). An apoptotic process including caspase‐1 and ‐3 has been shown to participate in the pathogenesis of FALS transgenic (Tg) mouse model. Here we report that IAP proteins, potent inhibitors of apoptosis, are involved in the FALS Tg mouse pathologic process. The levels of X‐linked inhibitor of apoptosis protein (XIAP) mRNA and protein were significantly decreased in the spinal cord of symptomatic G93A‐SOD1 Tg mice compared with littermates. In contrast, the levels of cIAP‐1 mRNA and protein were increased in symptomatic G93A‐SOD1 Tg mice, whereas the levels of cIAP‐2 mRNA and protein were unchanged. In situ hybridization showed that the expression of XIAP was remarkably reduced in the motor neurons of Tg mice, and the expression of cIAP‐1 was strongly increased in the reactive astrocytes of Tg mice. Overexpression of XIAP markedly inhibited the cell death and caspase‐3 activity in the neuro2a cells expressing mutant SOD1. Deletional mutant analysis revealed that the N‐terminal domain of XIAP, the BIR1‐2 domains, was essential for this inhibitory activity. These results suggest that XIAP plays a role in the apoptotic mechanism in the progression of disease in mutant SOD1 Tg mice and holds therapeutic possibilities for FALS.
Gene expression profile after intense second messenger activation in cortical primary neurones
Authors: Mayer Peter , Ammon Susanne , Braun Holger , Tischmeyer Helga , Riechert Uta , Kahl Evelyn , Höllt Volker
Published: March 2003

Numerous stimuli induce immediate early gene (IEG) expression in neurones, but a comprehensive overview of the late‐response genes is lacking. Therefore we aimed to identify changes in the neuronal gene expression profile following intense stimulation. Forskolin and 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA), direct activators of intracellular second messengers, were applied to primary cultured cortical neurones. The gene expression profiles were analyzed on Affymetrix DNA chips which cover around 8000 rat genes. Out of these, 95 genes (1.2%) were increased at least three‐fold, and 43 genes (0.5%) were at least three‐fold decreased. The gene chip results were verified by testing 15 of the altered genes by quantitative real‐time PCR. The majority of the up‐regulated genes were transcription factors, neurotrophic factors or (putative) neuropeptides. Furthermore, there were marked changes in intracellular signal processing enzymes and in postsynaptic structural proteins (e.g. vesl, arc, narp), which have been implicated in synaptic plasticity. Notably, classical players in neurotransmission or plasticity such as glutamate and GABA receptors or voltage‐gated ion channels were not increased. It is likely that the increased production of components of intracellular signalling and of postsynaptic proteins is involved in neuronal plasticity.
Cholesterol‐dependent modulation of the toxicity of HIV‐1 coat protein gp120 in human neuroblastoma cells
Authors: Maccarrone Mauro , Navarra Michele , Catani Valeria , Corasaniti M. Tiziana , Bagetta Giacinto , Finazzi‐Agrò Alessandro
Published: March 2003

The human immunodeficiency virus type 1 (HIV‐1) coat glycoprotein gp120 binds to its (co)receptors and orchestrates cell entry by the direct fusion of viral and target cell membranes. Here, we modulated membrane fluidity of human neuroblastoma CHP100 cells by modulating their cholesterol content, and investigated the ability of gp120 to induce cell death in comparison with the untreated cells. We show that in normal CHP100 cells gp120 induces necrosis by: (i) increased cyclooxygenase and 5‐lipoxygenase activity, and metabolites generated thereof (prostaglandin E2 and leukotriene B4, respectively); (ii) increased membrane lipoperoxidation; and (iii) increased mitochondrial uncoupling. These events were triggered by a rapid increase in intracellular calcium, and in cholesterol‐depleted cells engaged CXCR4 chemokine receptors. The intracellular calcium chelator EGTA‐AM protected CHP100 cells almost completely against the toxic effects of gp120. However, gp120‐induced necrosis and related biochemical changes were negligible in cholesterol‐enriched, and significantly enhanced in cholesterol‐depleted, CHP100 cells exposed to the viral glycoprotein under the same experimental conditions. Taken together, these results suggest that membrane fluidity may control the neurotoxic effects of HIV‐1 glycoprotein gp120.
Proteasomal dysfunction induced by 4‐hydroxy‐2,3‐trans‐nonenal, an end‐product of lipid peroxidation: a mechanism contributing to neurodegeneration?
Authors: Hyun Dong‐Hoon , Lee Moon‐Hee , Halliwell Barry , Jenner Peter
Published: March 2003

4‐Hydroxy‐2,3‐trans‐nonenal (HNE) is a neurotoxic unsaturated aldehyde end‐product of lipid peroxidation. The addition of HNE to NT‐2 and SK‐N‐MC cell lines induces apoptosis and we now investigated the time‐course of events occurring prior to apoptosis. Treatment of both NT‐2 and SK‐N‐MC cell lines with HNE led to HNE association with the proteasome, increased levels of protein carbonyls and ubiquitinated proteins, and decreased proteasomal function. There was also decreased metabolic activity, cytochrome c release and activation of caspase 3, followed by apoptotic changes including chromatin condensation, cell shrinkage and DNA fragmentation and laddering. Overexpression of mutant superoxide dismutase 1 proteins associated with amyotrophic lateral sclerosis decreased proteasomal activities in the absence of HNE and accelerated the apoptosis induced by HNE. By contrast, overexpression of wild‐type superoxide dismutase 1 did not affect basal levels of proteasomal activity. The data suggest that accumulation of ubiquitinated proteins and impairment of proteasomal function are important events in HNE toxicity. We propose that the proteasomal system is a significant target of HNE neurotoxicity in a wide range of neurodegenerative diseases, especially if abnormal proteins are being expressed.
Circadian rhythmicity in dopamine content of mammalian retina: role of the photoreceptors
Authors: Doyle Susan E. , McIvor Wilson E. , Menaker Michael
Published: March 2003

Dopamine, the predominant retinal catecholamine, is a neurotransmitter and neuromodulator known to regulate light‐adaptive retinal processes. Because dopamine influences several rhythmic events in the retina it is also a candidate for a retinal circadian signal. Using high performance liquid chromatography (HPLC), we have tested whether dopamine and its breakdown products are rhythmic in Royal College of Surgeons (RCS) rats with normal and dystrophic retinas. In both normal and mutant animals entrained to a 12‐h light/12‐h dark cycle, we found robust daily rhythms of dopamine and its two major metabolites. To address circadian rhythmicity of dopamine content, rats were entrained to light/dark cycles and released into constant darkness, using the circadian rhythm of wheel‐running activity as a marker of each individual's circadian phase. Circadian rhythms of dopamine and metabolite content persisted in both wild type and retinally degenerate animals held for two weeks in constant darkness. Our results demonstrate for the first time clear circadian rhythms of dopamine content and turnover in a free‐running mammal, and suggest that rods and cones are not required for dopamine rhythmicity .
Dietary low linolenic acid compared with docosahexaenoic acid alter synaptic plasma membrane phospholipid fatty acid composition and sodium–potassium ATPase kinetics in developing rats
Authors: Bowen Raffick A. R. , Clandinin Michael T.
Published: March 2003

The objective of this study was to investigate if maternal dietary 20:4n‐6 arachidonic acid (AA) and 22:6n‐3 compared with adequate or low levels of 18:3n‐3 linolenic acid (LNA) increases synaptic plasma membrane (SPM) cholesterol and phospholipid content, phospholipid 20:4n‐6 and 22:6n‐3 content, and Na,K‐ATPase kinetics in rat pups at two and five weeks of age. At parturition, Sprague‐Dawley rats were fed semi‐purified diets containing either AA + docosahexaenoic acid (DHA), adequate LNA (control; 18:2n‐6 : 18:3n‐3 ratio of 7.1 : 1) or low LNA (18:2n‐6 : 18:3n‐39 ratio of 835 : 1). During the first two weeks of life, the rat pups received only their dams' milk. After weaning, pups received the same diet as their respective dams to five weeks of age. No significant difference was observed among rat pups fed the diet treatments for SPM cholesterol or total and individual phospholipid content at two and five weeks of age. Fatty acid analysis revealed that maternal dietary AA + DHA, compared with feeding the dams the control diet or the low LNA diet, increased 20:4n‐6 in phosphatidylserine and 22:6n‐3 content of SPM phospholipids. Rats fed dietary AA + DHA or the control diet exhibited a significantly increased Vmax for SPM Na,K‐ATPase. Diet treatment did not alter the Km (affinity) of SPM Na,K‐ATPase in rat pups at two and five weeks of age. It is concluded that dietary AA + DHA does not alter SPM cholesterol and phospholipid content but increases the 22:6n‐3 content of SPM phospholipids modulating activity of Na,K‐ATPase.
Kainate‐induced excitotoxicity is dependent upon extracellular potassium concentrations that regulate the activity of AMPA/KA type glutamate receptors
Authors: Ha Byeong Keun , Vicini Stefano , Rogers Richard C. , Bresnahan Jacqueline C. , Burry Richard W. , Beattie Michael S.
Published: March 2003

In addition to well‐known N‐methyl‐d‐aspartate (NMDA) receptor‐mediated excitotoxicity, recent studies suggest that non‐NMDA type ionotropic glutamate receptors are also important mediators of excitotoxic neuronal death, and that their functional expression can be regulated by the cellular environment. In this study, we used cerebellar granule cells (CGCs) in culture to investigate kainate (KA)‐induced excitotoxicity. Although previous reports indicated that KA induces apoptosis of CGCs in culture, no KA‐induced excitotoxic cell death was observed in CGCs treated with KA when cells were maintained in high potassium media (24 mm K+). In contrast, when mature CGCs were shifted into low potassium media (3 mm K+), KA produced significant excitotoxicity. In electrophysiological studies, the KA‐induced inward current density was significantly elevated in CGCs shifted into low K+ media compared with those maintained in high K+ media. Non‐desensitizing aspects of KA currents observed in this study suggest that these responses were mediated by AMPA rather than KA receptors. In immunofluorescence studies, the surface expression of GluR1 subunits increased when mature CGCs were shifted into a low K+ environment. This study suggests that KA‐induced excitotoxicity in mature CGCs is dependent upon the extracellular potassium concentration, which modulates functional expression and excitability of AMPA/KA receptors.
Gene expression analysis of spontaneously hypertensive rat cerebral cortex following transient focal cerebral ischemia
Authors: Raghavendra Rao Vemuganti L. , Bowen Kellie K. , Dhodda Vinay K. , Song Guoqing , Franklin James L. , Gavva Narender R. , Dempsey Robert J.
Published: March 2003

Identification of novel modulators of ischemic neuronal death helps in developing new strategies to prevent the stroke‐induced neurological dysfunction. Hence, the present study evaluated the gene expression changes in rat cerebral cortex at 6 and 24 h of reperfusion following transient middle cerebral artery occlusion (MCAO) by GeneChip® analysis. Transient MCAO resulted in selective increased mRNA levels of genes involved in stress, inflammation, transcription and plasticity, and decreased mRNA levels of genes which control neurotransmitter function and ionic balance. In addition to a number of established ischemia‐related genes, many genes not previously implicated in transient focal ischemia‐induced brain damage [suppressor of cytokine signaling (SOCS)‐3, cAMP responsive element modulator (CREM), cytosolic retinol binding protein (CRBP), silencer factor‐B, survival motor neuron (SMN), interferon‐γ regulatory factor‐1 (IRF‐1), galanin, neurotrimin, proteasome subunit RC8, synaptosomal‐associated protein (SNAP)‐25 A and B, synapsin 1a, neurexin 1‐β, ras‐related rab3, vesicular GABA transporter (VGAT), digoxin carrier protein, neuronal calcium sensor‐1 and neurodap] were observed to be altered in the ischemic cortex. Real‐time PCR confirmed the GeneChip® results for several of these transcripts. SOCS‐3 is a gene up‐regulated after ischemia which modulates inflammation by controlling cytokine levels. Antisense knockdown of ischemia‐induced SOCS‐3 protein expression exacerbated transient MCAO‐induced infarct volume assigning a neuroprotective role to SOCS‐3, a gene not heretofore implicated in ischemic neuronal damage.
Microglia enhance β‐amyloid peptide‐induced toxicity in cortical and mesencephalic neurons by producing reactive oxygen species
Authors: Qin Liya , Liu Yuxin , Cooper Cynthia , Liu Bin , Wilson Belinda , Hong Jau‐Shyong
Published: March 2003

The purpose of this study was to assess and compare the toxicity of β‐amyloid (Aβ) on primary cortical and mesencephalic neurons cultured with and without microglia in order to determine the mechanism underlying microglia‐mediated Aβ‐induced neurotoxicity. Incubation of cortical or mesencephalic neuron‐enriched and mixed neuron–glia cultures with Aβ(1–42) over the concentration range 0.1–6.0 μm caused concentration‐dependent neurotoxicity. High concentrations of Aβ (6.0 μm for cortex and 1.5–2.0 μm for mesencephalon) directly injured neurons in neuron‐enriched cultures. In contrast, lower concentrations of Aβ (1.0–3.0 μm for cortex and 0.25–1.0 μm for mesencephalon) caused significant neurotoxicity in mixed neuron–glia cultures, but not in neuron‐ enriched cultures. Several lines of evidence indicated that microglia mediated the potentiated neurotoxicity of Aβ, including the observations that low concentrations of Aβ activated microglia morphologically in neuron–glia cultures and that addition of microglia to cortical neuron–glia cultures enhanced Aβ‐induced neurotoxicity. To search for the mechanism underlying the microglia‐mediated effects, several proinflammatory factors were examined in neuron–glia cultures. Low doses of Aβ significantly increased the production of superoxide anions, but not of tumor necrosis factor‐α, interleukin‐1β or nitric oxide. Catalase and superoxide dismutase significantly protected neurons from Aβ toxicity in the presence of microglia. Inhibition of NADPH oxidase activity by diphenyleneiodonium also prevented Aβ‐induced neurotoxicity in neuron–glia mixed cultures. The role of NADPH oxidase‐generated superoxide in mediating Aβ‐induced neurotoxicity was further substantiated by a study which showed that Aβ caused less of a decrease in dopamine uptake in mesencephalic neuron–glia cultures from NADPH oxidase‐deficient mutant mice than in that from wild‐type controls. This study demonstrates that one of the mechanisms by which microglia can enhance the neurotoxicity of Aβ is via the production of reactive oxygen species.
Cholesterol accumulates in cell bodies, but is decreased in distal axons, of Niemann–Pick C1‐deficient neurons
Authors: Karten Barbara , Vance Dennis E. , Campenot Robert B. , Vance Jean E.
Published: March 2003

Niemann–Pick type‐C (NPC) disease is characterized by a progressive loss of neurons and an accumulation of unesterified cholesterol within the endocytic pathway. Unlike other tissues, however, NPC1‐deficient brains do not accumulate cholesterol but whether or not NPC1‐deficient neurons accumulate cholesterol is not clear. Therefore, as most studies on cholesterol homeostasis in NPC1‐deficient cells have been performed in fibroblasts we have investigated cholesterol homeostasis in cultured murine sympathetic neurons lacking functional NPC1. These neurons did not display obvious abnormalities in growth or morphology and appeared to respond normally to nerve growth factor. Filipin staining revealed numerous cholesterol‐filled endosomes/lysosomes in NPC1‐deficient neurons and the mass of cholesterol in cell bodies was greater than in wild‐type neurons. Surprisingly, however, the cholesterol content of NPC1‐deficient and wild‐type neurons as a whole was the same. This apparent paradox was resolved when the cholesterol content of NPC1‐deficient distal axons was found to be less than of wild‐type axons. Cholesterol sequestration in cell bodies did not depend on exogenously supplied cholesterol since the cholesterol accumulated before birth and did not disperse when neurons were cultured without exogenous cholesterol. The altered cholesterol distribution between cell bodies and axons suggests that transport of cholesterol, particularly that synthesized endogenously, from cell bodies to distal axons is impaired in NPC1‐deficient neurons.
Heterogeneous expression of the triggering receptor expressed on myeloid cells‐2 on adult murine microglia
Authors: Schmid Christoph D. , Sautkulis Lauren N. , Danielson Patria E. , Cooper Judith , Hasel Karl W. , Hilbush Brian S. , Sutcliffe J. Gregor , Carson Monica J.
Published: March 2003

Microglial activation is an early and common feature of almost all neuropathologies, including multiple sclerosis, Alzheimer's disease and mechanical injury. To better understand the relative contributions microglia make toward neurodegeneration and neuroprotection, we used TOGA® to identify molecules expressed by microglia and regulated by inflammatory signals. Triggering receptor expressed on myeloid cells‐2 (TREM‐2) was among the mRNAs identified as being expressed by unactivated microglia, but down‐regulated by lipopolysaccharide/interferon γ. In the healthy CNS, not all microglia expressed TREM‐2. Microglial expression of TREM‐2 varied not only between brain regions but also within each brain region. Brain regions with an incomplete blood–brain barrier had the lowest percentages of TREM‐2‐ expressing microglia, whereas the lateral entorhinal and cingulate cortex had the highest percentages. A novel form of TREM‐2b that lacked a transmembrane domain was detected, perhaps indicating a soluble form of the protein. Taken together, these data suggest that (1) subsets of microglia are specialized to respond to defined extracellular signals; and (2) regional variations in TREM‐2 expression may contribute to the varying sensitivities of different brain regions to similar pathological signals.
Circadian regulation of a transcription factor, ApC/EBP, in the eye of Aplysia californica
Authors: Hattar Samer , Lyons Lisa C. , Dryer Laurence , Eskin Arnold
Published: March 2003

The transcription factor, ApC/EBP (Aplysia CCAAT enhancer‐binding protein) is an immediate early gene that is rapidly induced by serotonin and the cAMP signaling pathway. ApC/EBP acts as an important link following the activation of protein kinase A (PKA) in the consolidation of long‐term memory in Aplysia californica. In this study, we report that levels of ApC/EBP mRNA in the eye of Aplysia are modulated by serotonin or light. These responses of ApC/EBP to serotonin and light are mimicked by analogs of cAMP and cGMP. Expression of ApC/EBP in the eye is also under the control of the circadian oscillator with circadian rhythms of ApC/EBP mRNA present under constant dark conditions. Therefore, ApC/EBP is a candidate gene for a circadian transcription factor to mediate circadian responses activated by the cAMP and cGMP second messenger signaling pathways.
Up‐regulation of the neuronal serotoninergic phenotype in vitro: BDNF and cAMP share Trk B‐dependent mechanisms
Authors: Rumajogee Prakasham , Madeira Alexandra , Vergé Daniel , Hamon Michel , Miquel Marie‐Christine
Published: March 2003

The effects of brain‐derived neurotrophic factor (BDNF) and cAMP on the neuronal serotoninergic phenotype were studied in primary cultures of E14 rat embryonic rostral raphe. Short treatments (for 18 h) with BDNF or dibutyryl‐cAMP induced an almost two‐fold increase in the number of serotoninergic neurones and a dramatic extension and ramification of their neurites. These changes were associated with marked increases in the levels of mRNAs encoding the serotonin transporter, the 5‐HT1A and 5‐HT1B receptors and the BDNF receptor tyrosine kinase B (TrkB). Concomitant blockade of tyrosine kinases by genistein suppressed all the up‐regulating effects of BDNF and cAMP on 5‐hydroxytryptamine (5‐HT) neurones. These findings suggest that an auto‐amplifying mechanism underlies the promoting effect of BDNF on the differentiation of serotoninergic neurones through TrkB activation, which is also triggered by cAMP.
Age‐dependent myelin degeneration and proteolysis of oligodendrocyte proteins is associated with the activation of calpain‐1 in the rhesus monkey
Authors: Sloane J. A. , Hinman J. D. , Lubonia M. , Hollander W. , Abraham C. R.
Published: March 2003

Myelin provides important insulating properties to axons allowing for propagation of action potentials over large distances at high velocity. Disruption of the myelin sheath could therefore contribute to cognitive impairment, such as that observed during the normal aging process. In the present study, age‐related changes in myelin, myelin proteins and oligodendrocyte proteins were assessed in relationship to calpain‐1 expression and cognition in the rhesus monkey. Isolation of myelin fractions from brain white matter revealed that as the content of the intact myelin fraction decreased with age, there was a corresponding increase in the floating or degraded myelin fraction, suggesting an increased breakdown of intact myelin with age. Of the myelin proteins examined, only the myelin‐associated glycoprotein decreased with age. Levels of the oligodendrocyte‐specific proteins 2′,3′‐cyclic nucleotide 3′‐phosphodiesterase (CNPase) and myelin/oligodendrocyte‐specific protein (MOSP) increased dramatically in white matter homogenates and myelin with age. Age‐related increases in degraded CNPase also were demonstrable in white matter in association with increases in activated calpain‐1. Degraded CNPase was also detectable in myelin fractions, with only the floating fraction containing activated calpain‐1. The increases in the activated enzyme in white matter were much greater than those found in myelin fractions suggesting a source other than the myelin membrane for the marked overexpression of activated calpain‐1 with age. In addition, CNPase was demonstrated to be a substrate for calpain in vitro. In summary, changes in myelin and oligodendrocyte proteins occur with age, and they appear to have a significant relationship to cognitive impairment. The overexpression of CNPase and MOSP suggests new formation of myelin by oligodendrocytes, which may occur in response to myelin degradation and injury caused by proteolytic enzymes such as calpain.
Regulation of c‐Jun N‐terminal kinase, p38 kinase and AP‐1 DNA binding in cultured brain neurons: roles in glutamate excitotoxicity and lithium neuroprotection
Authors: Chen Ren‐Wu , Qin Zheng‐Hong , Ren Ming , Kanai Hirohiko , Chalecka‐Franaszek Elzbieta , Leeds Peter , Chuang De‐Maw
Published: March 2003

In rat cerebellar granule cells, glutamate induced rapid activation of c‐Jun N‐terminal kinase (JNK) and p38 kinase to phosphorylate c‐Jun (at Ser63) and p53 (at Ser15), respectively, and a subsequent marked increase in activator protein‐1 (AP‐1) binding that preceded apoptotic death. These glutamate‐induced effects and apoptosis could largely be prevented by long‐term (7 days) pretreatment with 0.5–2 mm lithium, an antibipolar drug. Glutamate's actions could also be prevented by known blockers of this pathway, MK‐801 (an NMDA receptor blocker), SB 203580 (a p38 kinase inhibitor) and curcumin (an AP‐1 binding inhibitor). The concentration‐ and time‐dependent suppression of glutamate's effects by lithium and curcumin correlated well with their neuroprotective effects. These results suggest a prominent role of JNK and p38, as well as their downstream AP‐1 binding activation and p53 phosphorylation in mediating glutamate excitotoxicity. Moreover, the neuroprotective effects of lithium are mediated, at least in part, by suppressing NMDA receptor‐mediated activation of the mitogen‐activated protein kinase pathway.
THIS ARTICLE HAS BEEN RETRACTED Activation of capsaicin‐sensitive primary sensory neurones induces anandamide production and release
Authors: Ahluwalia J. , Yaqoob Mohammed , Urban Laszlo , Bevan Stuart , Nagy Istvan
Published: March 2003

The inhibitory cannabinoid 1 receptor and the excitatory vanilloid receptor 1, both of which are responsive to the endogenous ligand anandamide, are co‐expressed on a subpopulation of primary sensory neurones. We report that activation of the cannabinoid 1 receptor/vanilloid receptor 1‐co‐expressing primary sensory neurones induces the production and release of anandamide. Application of capsaicin (3 nm−1 µm) to cultured primary sensory neurones evoked calcitonin gene‐related peptide release, which was significantly increased by the selective cannabinoid 1 receptor antagonist, SR141716A (200 nm). Mass spectrometric analyses of the extracellular solution revealed that exposure to capsaicin (10 nm or 100 nm) enhanced the anandamide concentration of the medium from less then 0.05 pmol/µL to more then 2 pmol/µL. Depolarization of the neurones with 50 mm KCl also enhanced the anandamide content of the buffer. Both the capsaicin‐ and KCl‐induced anandamide release depended on extracellular Ca2+. Prolonged treatment of the cultures with capsaicin (10 µm) reduced both the capsaicin‐ and KCl‐induced anandamide release. These findings indicate that activation of capsaicin‐sensitive primary sensory neurones evokes anandamide production and release, and that anandamide might be a key endogenous regulator of the excitability of these neurones.
Essential role for integrin linked kinase in Akt‐mediated integrin survival signaling in hippocampal neurons
Authors: Gary Devin S. , Milhavet Ollivier , Camandola Simonetta , Mattson Mark P.
Published: March 2003

Activation of integrin receptors in neurons can promote cell survival and synaptic plasticity, but the underlying signal transduction pathway(s) is unknown. We report that integrin signaling prevents apoptosis of embryonic hippocampal neurons by a mechanism involving integrin‐linked kinase (ILK) that activates Akt kinase. Activation of integrins using a peptide containing the amino acid sequence EIKLLIS derived from the α chain of laminin protected hippocampal neurons from apoptosis induced by glutamate or staurosporine, and increased Akt activity in a β1 integrin‐dependent manner. Transfection of neurons with a plasmid encoding dominant negative Akt blocked the protective effect of the integrin‐activating peptide, as did a chemical inhibitor of Akt. Although inhibitors of phosphoinositide‐3 (PI3) kinase blocked the protective effect of the peptide, we found no increase in PI3 kinase activity following integrin stimulation suggesting that PI3 kinase was necessary for Akt activity but was not sufficient for the increase in Akt activity following integrin activation. Instead, we show a requirement for ILK in integrin receptor‐induced Akt activation. ILK was activated following integrin stimulation and dominant negative ILK blocked integrin‐mediated Akt activation and cell survival. Activation of ILK and Akt were also required for neuroprotection by substrate‐associated laminin. These results establish a novel pathway that signals cell survival in neurons in response to integrin receptor activation.
The antioxidants α‐lipoic acid and N‐acetylcysteine reverse memory impairment and brain oxidative stress in aged SAMP8 mice
Authors: Farr Susan A. , Poon H. Fai , Dogrukol‐Ak Dilek , Drake Jeniffer , Banks William A. , Eyerman Edward , Butterfield D. Allan , Morley John E.
Published: March 2003

Oxidative stress may play a crucial role in age‐related neurodegenerative disorders. Here, we examined the ability of two antioxidants, α‐lipoic acid (LA) and N‐acetylcysteine (NAC), to reverse the cognitive deficits found in the SAMP8 mouse. By 12 months of age, this strain develops elevated levels of Aβ and severe deficits in learning and memory. We found that 12‐month‐old SAMP8 mice, in comparison with 4‐month‐old mice, had increased levels of protein carbonyls (an index of protein oxidation), increased TBARS (an index of lipid peroxidation) and a decrease in the weakly immobilized/strongly immobilized (W/S) ratio of the protein‐specific spin label MAL‐6 (an index of oxidation‐induced conformational changes in synaptosomal membrane proteins). Chronic administration of either LA or NAC improved cognition of 12‐month‐old SAMP8 mice in both the T‐maze footshock avoidance paradigm and the lever press appetitive task without inducing non‐specific effects on motor activity, motivation to avoid shock, or body weight. These effects probably occurred directly within the brain, as NAC crossed the blood–brain barrier and accumulated in the brain. Furthermore, treatment of 12‐month‐old SAMP8 mice with LA reversed all three indexes of oxidative stress. These results support the hypothesis that oxidative stress can lead to cognitive dysfunction and provide evidence for a therapeutic role for antioxidants.
Cloning and characterization of a novel variant (mM‐rdgBβ1) of mouse M‐rdgBs, mammalian homologs of Drosophila retinal degeneration B gene proteins, and its mRNA localization in mouse brain in comparison with other M‐rdgBs
Authors: Takano Nobuo , Owada Yuji , Suzuki Ryoji , Sakagami Hiroyuki , Shimosegawa Tooru , Kondo Hisatake
Published: March 2003

We report the cloning, characterization and localization in the brain of a novel isoform termed mM‐rdgBβ1 (mouse type of mammalian retinal degeneration Bβ1 protein) in comparison with the localization of three known mammalian homologs (M‐rdgBβ, M‐rdgB1, M‐rdgB2). mM‐rdgBβ1 cDNA contains a sequence of 119 bp as a form of insertion in the open reading frame of the known mM‐rdgBβ, and encodes a protein of 269 amino acids with a calculated molecular mass of 31.7 kDa, different from the molecular mass of 38.3 kDa of mM‐rdgBβ. It also contains a phosphatidylinositol transfer protein (PITP)‐like domain similar to the known three homologs, as well as D‐rdgB. The recombinant mM‐rdgBβ1 protein shows the specific binding activity to phosphatidylinositol but not to other phospholipids. This novel molecule is localized not only in the cytoplasm but also in the nucleus, different from the cytoplasmic localization of mM‐rdgBβ. In in situ hybridization analysis, the gene expression for mM‐rdgBβ1 in the brain, though weak, is rather confined to the embryonic stage, different from wider expression of mM‐rdgBβ in the gray matters of pre‐ and post‐natal brains. Taken together, mM‐rdgBβ1 is suggested to play a role in the phosphoinositide‐mediated signaling in the neural development.
The interaction with the cytoplasmic loops of rhodopsin plays a crucial role in arrestin activation and binding
Authors: Raman Dayanidhi , Osawa Shoji , Gurevich Vsevolod V. , Weiss Ellen R.
Published: March 2003

The binding of arrestin to rhodopsin is initiated by the interaction of arrestin with the phosphorylated rhodopsin C‐terminus and/or the cytoplasmic loops, followed by conformational changes that expose an additional high‐affinity site on arrestin. Here we use an arrestin mutant (R175E) that binds similarly to phosphorylated and unphosphorylated, wild‐type rhodopsin to identify rhodopsin elements other than C‐terminus important for arrestin interaction. R175E‐arrestin demonstrated greatly reduced binding to unphosphorylated cytoplasmic loop mutants L72A, N73A, P142A and M143A, suggesting that these residues are crucial for high‐affinity binding. Interestingly, when these rhodopsin mutants are phosphorylated, R175E‐arrestin binding is less severely affected. This effect of phosphorylation on R175E‐arrestin binding highlights the co‐operative nature of the multi‐site interaction between arrestin and the cytoplasmic loops and C‐terminus of rhodopsin. However, a combination of any two mutations disrupts the ability of phosphorylation to enhance binding of R175E‐arrestin. N73A, P142A and M143A exhibited accelerated rates of dissociation from wild‐type arrestin. Using sensitivity to calpain II as an assay, these cytoplasmic loop mutants also demonstrated reduced ability to induce conformational changes in arrestin that correlated with their reduced ability to bind arrestin. These results suggest that arrestin bound to rhodopsin is in a distinct conformation that is co‐ordinately regulated by association with the cytoplasmic loops and the C‐terminus of rhodopsin.
Pharmacological blockade of mGlu2/3 metabotropic glutamate receptors reduces cell proliferation in cultured human glioma cells
Authors: D'Onofrio Mara , Arcella Antonietta , Bruno Valeria , Ngomba Richard T. , Battaglia Giuseppe , Lombari Vincenza , Ragona Giuseppe , Calogero Antonella , Nicoletti Ferdinando
Published: March 2003

Glial cell proliferation in culture is under the control of metabotropic glutamate (mGlu) receptors. We have examined whether this control extends to human glioma cells. Primary cultures were prepared from surgically removed human glioblastomas. RT‐PCR combined with western blot analysis showed that most of the cultures (eight out of 11) expressed group‐II mGlu receptors. In two selected cultures (MZC‐12 and FCN‐9), the mGlu2/3 receptor antagonist, LY341495, slowed cell proliferation when applied to the growth medium from the second day after plating. This effect was reversible because linear cell growth was restored after washing out the drug. LY341495 reduced glioma cell proliferation at concentrations lower than 100 nm, which are considered as selective for mGlu2/3 receptors. In addition, its action was mimicked by the putative mGlu2/3 receptor antagonist (2S)‐α‐ethylglutamate. The anti‐proliferative effect of LY341495 was confirmed by measuring [methyl‐3H]‐thymidine incorporation in cultures arrested in G0 phase of the cell cycle and then stimulated to proliferate by the addition of 10% fetal calf serum or 100 ng/mL of epidermal growth factor (EGF). In cultures treated with EGF, LY341495 was also able to reduce the stimulation of the mitogen‐activated protein kinase (MAPK) pathway, as well as the induction of cyclin D1. Both effects, as well as decreased [methyl‐3H]‐thymidine incorporation, were partially reduced by co‐addition of the potent mGlu2/3 receptor agonist, LY379268. We conclude that activation of group‐II mGlu receptors supports the growth of human glioma cells in culture and that antagonists of these receptors should be tested for their ability to reduce tumour growth in vivo.
The use of music to decrease agitated behaviour of the demented elderly: the state of the science
Authors: Lou Meei‐Fang
Published: March 2003

The use of music to decrease agitated behaviour of the demented elderly: the state of the science

This paper reviews the state of the science of interventions using music to decrease the agitated behaviour of the demented elderly person. Seven research articles were located through computerized databases. The review of the literature suggested that music therapy is a useful intervention to help patients deal with a range of behaviour problems. However, overall weakness and limitations of studies are considerable. More rigorous research designs are required to evaluate the immediate and sustained physiological, psychological and sociological effects of music therapy on agitation behaviours of demented elderly. Some recommendations for future research are provided.
A home rehabilitation program for stroke patients
Authors: Ljungberg Carin , Hanson Elizabeth , Lövgren Monika
Published: March 2003

The purpose of this study was to develop a rehabilitation program wherein the stroke team, patient and family act as partners in the rehabilitation process initially at hospital and subsequently on discharge for 4 weeks in the stroke patient's home. The study attempted to address the stroke patient's functional ability and life satisfaction from a holistic viewpoint. A quasi‐experimental design was used. Thirty‐two stroke patients participated in the intervention group and nine in the control group. The intervention group improved in functional ability after 4 weeks at home. They also participated in activities and were generally more active than the control group. Ninety percent of the families in the intervention group experienced high life satisfaction levels after the training period. However this satisfaction decreased after 6 months, and one year post‐stroke, the patient and family's life satisfaction levels increased once more. It is likely that being given the opportunity to make one's own decisions, to be more active and motivated led to improvements in patients' daily life functions as they were able to carry out their preferred activities in the comfort of their own home. The program shortened the admission time for the intervention group by one‐third.
A comparison of the health locus of control and perceived social support between cancer and AIDS patients
Authors: Chen Mei‐Ling , Deng Shiu‐Lai , Chang Hsien‐Kun
Published: March 2003

This study compared the health locus of control (HLOC) and perceived social support levels of 219 cancer patients and 122 acquired immunodeficiency syndrome (AIDS) patients. Further, the relationship between HLOC and social support was explored. Chinese versions of the Multidimensional Health Locus of Control Scale (MHLC) (Form B) and the Personal Resources Questionnaire (PRQ) (Part 2) were used. Results showed that AIDS patients have a higher internal HLOC than cancer patients. The perceived social support of cancer patients was higher than that of AIDS patients. Social support was positively associated with internal HLOC and negatively associated with chance HLOC in both the samples. Implications of these results for nursing practice and future research are discussed.
Dependency as disadvantage – patients' experiences
Authors: Ellefsen Bodil
Published: March 2003

Dependency as disadvantage – patients' experiences

This is an empirical qualitative study of the dependent community patient. The investigation raises the question of what it is like to be a highly dependent patient and how they relate to the situation. A non‐probability, volunteer sample was selected from home nursing patients in a large town in Norway. The data were collected through in‐depth interviews with 15 patients in their home using a semistructured interview guide. A constant comparative approach was used for analysing data. The results show that dependency has disadvantages like constraints and burdens in daily life. The patient adjusts both in a reactive and proactive way. The constraints are apparent through reduced autonomy in daily life and limited possibilities for negotiation. The burden is demonstrated through uncertainty within the encounter situation, low esteem, and loss of privacy. Adjustment is made through planning, guidance of the carer, acceptance of the situation, positive self‐image and by protection of family and carer, and placing blame on the bureaucracy. The patient reacts in a more passive, reactive way regarding circumstances connected to the health care system and in a more proactive way by trying to influence the situation in the interaction in the private sphere of the patient's home.
Characterization of microsatellite loci in the parasitoid, Cotesia congregata (Say) (Hymenoptera Braconidae)
Authors: Jensen M. Kathleene , Kester Karen M. , Kankare Maaria , Brown Bonnie L.
Published: March 2003

Nine microsatellite loci were developed and assayed for polymorphism in four groups of the insect parasitoid, Cotesia congregata (Say) (Hymenoptera). One locus was monomorphic and eight were polymorphic in C. congregata. Allelic distributions differed significantly between groups of C. congregata collected from solanaceous and catalpa host food plants (P = 0). Loci were tested for cross‐reactivity to six congeners: C. acuminata (Reinhard), C. bignellii (Marshall), C. cynthiae (Nixon), C. euphydryidis (Musebeck), C. koebelei (Riley) and C. melitaearum (Wilkinson). In the congeners, eight loci were polymorphic, four of which yielded allele sizes that differed substantially from sizes of amplification products observed for C. congregata.
Identification of polymorphic microsatellite loci in the mud crab Scylla serrata (Brachyura: Portunidae)
Authors: Gopurenko David , Hughes Jane M. , Ma Jing
Published: March 2003

Five microsatellite loci are identified and characterized from the genome of Scylla serrata, a widespread and commercially important species of coastal marine crab. The loci were detected by randomly screening for di‐ and tri‐nucleotide repeat units within a partial genomic library developed for the species. The five loci consist of dinucleotide repeats and are both co‐dominant and polymorphic within the species. A sample (N = 36) of S. serrata from one Australian population has an average observed heterozygosity of 0.875 and provides no evidence of either linkage among loci or significant deviation from random mating expectations across loci. PCR products for each of the five loci were also observed from a small sample of three other species within the Scylla genus. These markers may provide genetic information that will be useful for both aquaculture and studies of natural populations of the genus.
Characterization of microsatellite loci in Lychnis flos‐cuculi (Caryophyllaceae)
Authors: Galeuchet D. J. , Husi R. , Perret C. , Fischer M. , Gautschi B.
Published: March 2003

We cloned microsatellite repeats from ragged robin Lychnis flos‐cuculi (Caryophyllaceae) and developed 20 primer pairs for microsatellite marker analysis. We used 18 individuals of a large Swiss population to screen microsatellites. Seven loci were polymorphic. Between seven and 11 alleles were found per locus and the observed heterozygosity was between 0.308 and 0.813. Observed heterozygote deficits were significant in five of the seven loci, in line with the mixed mating system of L. flos‐cuculi.
Characterization of microsatellite loci in sea urchins (Strongylocentrotus spp.)
Authors: Addison J. A. , Hart M. W.
Published: March 2003

We present six dinucleotide repeats that were developed and characterized in Strongylocentrotus droebachiensis and also tested in S. purpuratus. Four of these loci are polymorphic in S. droebachiensis (13–20 alleles, N= 100) and five are polymorphic in S. purpuratus (5–12 alleles, N= 10). We are currently using these markers to investigate the population substructure of shallow water populations of S. droebachiensis in the north Atlantic.
Microsatellite DNA markers for two endemic ground beetles: Carabus punctatoauratus and C. solieri
Authors: Garnier S. , Brouat C. , Mondor‐Genson G. , Prieur B. , Sennedot F. , Rasplus J.‐Y.
Published: March 2003

We isolated and characterized nine and five polymorphic microsatellite loci in the respective ground beetles Carabus punctatoauratus and C. solieri. We tested cross‐species amplification of all these loci plus six isolated in C. solieri and for which primers sequences were soon published. From these combined analyses, we obtained 14 and 17 polymorphic markers, respectively, for C. punctatoauratus and C. solieri.
Cosmetic dermatology: no need for an apology
Authors: Parish Lawrence Charles
Published: March 2003

Summary Cosmetic dermatology should be an established part of the practice of dermatology. No ifs, ands, or buts. Patients want to look their best, and they have every right to achieve this goal.1
Red hair − a desirable mutation?
Authors: Ha Thomas , Rees Jonathan L
Published: March 2003

Summary Red hair is one of the most striking variants of human hair coloration and has historically been of profound social importance. Red hair in man is due to certain loss of function mutations of one of the peptide products of the pro‐opiomelanocortin (POMC) gene, the melanocortin‐1 receptor (MC1R, MIM 155555). Such functional mutations enable the melanocyte to produce red‐yellow pheomelanin in preference to the default, black‐brown eumelanin. This paper reviews the path of discovery of the MC1R in control of animal coat colour, the subsequent role of MC1R in human physiology and possibly wider role of MC1R in human skin carcinogenesis and human development through history.
Heat and mosquitoes cause breeding failures and adult mortality in an Arctic‐nesting seabird
Authors: Gaston Anthony J. , Hipfner J. Mark , Campbell Doug
Published: March 2003

We report on variation in rates of egg loss among Brünnich’s GuillemotUria lomviabreeding at Coats Island, northern Hudson Bay, in 1997–1999, and on several cases of adult mortality during incubation in the same years. Common factors in the dates of peak egg loss and adult mortality were high maximum daily temperatures and the presence of high numbers of mosquitoes in the area. Mortality was confined to breeding sites close to the edge of the colony, where mosquito parasitism was highest, and to those sites exposed to afternoon sunshine. High temperatures that occurred on days without mosquitoes were not associated with high egg losses or with adult mortality. Hence, it appears that a combination of heat and mosquitoes was necessary to bring about observed mortality and egg losses. The dates of first appearance and peak abundance of mosquitoes at Coats Island have advanced since the mid‐1980s, perhaps in response to ongoing climate change. The effects on breeding Brünnich’s Guillemots suggest that the birds have not had time to adjust their behaviour to the resulting changes in the timing of peak mosquito parasitism.
Sex‐biased survival and breeding dispersal probability in a patchy population of the Rock SparrowPetronia petronia
Authors: Tavecchia G. , Pradel R. , Lebreton J‐D. , Biddau L. , Mingozzi T.
Published: March 2003

Demographic parameters of the polygynous Rock SparrowPetronia petroniawere investigated in a small patchy population in the Italian Alps. The population included two distinct breeding patches that differed in altitude and breeding success. Survival parameters were estimated by capture–recapture analysis of 170 individually marked animals. At the whole population level (Cormack–Jolly Seber model), no sex difference in local survival probability was detected. We then used a multisite capture–recapture approach (Arnason–Schwarz model) to investigate patch‐specific survival probability and between‐patch dispersal rate conditional on survival. Female local survival in the higher‐altitude patch (mean ± se: 0.54 ± 0.04) was significantly greater than in the other patch (0.37 ± 0.04), probably because permanent emigration from the study area was greater. In the higher‐altitude patch, breeding dispersal was constrained by the altitude limit and breeding movements were directed toward the patch at lower altitude. The probability of changing patch in the next breeding season was significantly higher for females (range 0.16–0.21) than for males (0.01–0.03). Breeding success varied between years and patches, being lower in the patch where frequency of polygamy and female local mortality were higher.