bluuebunny/crossref_metadata_2025_split huggingface dataset:
Factors affecting consumer acceptance of chilled ready meals on the island of Ireland
Authors: Reed Zandra , McIlveen‐Farley Heather , Strugnell Christopher 
Published: March 2003

AbstractThe chilled ready meal market on the island of Ireland is relatively young but is growing rapidly. This paper focused on a consumer questionnaire (n = 702), designed to examine consumer attitudes to and consumption of chilled ready meals, in both the north and south of Ireland. This formed part of a larger study, with the questionnaire findings contributing to an in‐depth sensory study on a selected range of chilled ready meals. For a significant number of Irish consumers, consumption of these products is higher than on the UK mainland. For others, the products are purchased as a convenient alternative or a weekly treat. Respondents in urban locations were significantly more likely to consume chilled ready meals, as were men and younger, single respondents. Irish consumers are becoming more accustomed to ethnic cuisine although traditional meals remain popular. There is a clear need for developers to continue to enhance the sensory quality of these products, particularly as the primary barrier to consumption was a preference for home cooked food. However, they must also strive to maintain consumer interest in the sector, fulfil the desire for convenience and satisfy a more discerning palate.
Proteolysis in miniature Cheddar‐type cheeses made using blends of chymosin and Cynara cardunculus proteinases as coagulant
Authors: O'Mahony James A , Sousa Maria J , Mcsweeney Paul L H 
Published: March 2003

Miniature (20 g) Cheddar‐type cheeses were manufactured using blends of Cynara cardunculus proteinases and chymosin as coagulant (100 : 0, 50 : 50, 25 : 75 and 0 : 100 C. cardunculus proteinases : chymosin). There were no substantial differences between the compositions of cheeses made using any of the four coagulant blends. Cheeses manufactured with coagulant blends containing C. cardunculus proteinases exhibited higher levels of pH 4.6‐soluble nitrogen than cheese made using chymosin as coagulant. The extent of breakdown of αs1‐casein, as measured by urea‐polyacrylamide gel electrophoresis (urea‐PAGE), was greater in cheeses made using coagulant preparations containing C. cardunculus proteinases as a constituent than in cheese made using 100% chymosin as coagulant. Different reverse‐phase high‐performance liquid chromatography (RP‐HPLC) peptide profiles of the ethanol‐soluble and ‐insoluble fractions were obtained for cheeses made using either C. cardunculus proteinases or chymosin as coagulant. Principal component analysis and hierarchical cluster analysis of RP‐HPLC data confirmed that the inclusion of even small proportions (25%) of C. cardunculus proteinases with chymosin in the coagulant blend greatly altered the pattern and extent of proteolysis in miniature Cheddar‐type cheeses.
Bidirectional modulation of P2X receptor‐mediated response by divalent cations in rat dorsal motor nucleus of the vagus neurons
Authors: Ueno Tsuyoshi , Ueno Shinya , Kakazu Yasuhiro , Akaike Norio , Nabekura Junichi 
Published: March 2003

The modulatory effects of Zn2+ and other divalent cations on the ATP‐induced responses of preganglionic neurons acutely dissociated from the rat dorsal motor nucleus of the vagus (DMV) were examined using a nystatin‐perforated patch technique under voltage‐clamp. DMV neurons were identified by back‐filling of DiI placed on the vagal bundle at the neck. Zn2+ exerts a concentration‐dependent effect on P2X receptor‐mediated current (IATP): a potentiation by low concentrations of Zn2+ (≤ 50 µm) and an inhibition by high concentrations (> 50 µm). Inhibition of the ATP response was associated with a prolongation of the rising phase of IATP. Cu2+ mimicked Zn2+ regarding the biphasic modulation of IATP. On the other hand, Ni2+ potentiated, but failed to inhibit, the ATP response even at a concentration of 3 mm. Quantitative RT‐PCR revealed the similarity of P2X2 mRNA expression between the DMV and superior cervical ganglion (SCG) but not in the dorsal root ganglion (DRG) and hypoglossal nucleus (XII). The results from the electrophysiological and molecular approaches suggest that functional P2X receptors expressed in DMV neurons are characterized mainly by the P2X2 and P2X2/6 subtype. DMV neurons possess similar P2X receptor characteristics to SCG neurons.
Characterization of GTP cyclohydrolase I gene expression in the human neuroblastoma SKN‐BE(2)M17: enhanced transcription in response to cAMP is conferred by the proximal promoter
Authors: Hirayama Kei , Shimoji Mika , Swick Lance , Meyer Amy , Kapatos Gregory 
Published: March 2003

GTP cyclohydrolase I (GTPCH) gene expression was investigated in the human monoamine‐containing neuroblastoma cell line SK‐N‐BE(2)M17. Northern blot analysis revealed a single GTPCH mRNA transcript that was confirmed by RNase protection assay to encode for Type 1 GTPCH; no alternatively spliced forms of GTPCH mRNA were detected with this assay. Incubation with 8Br‐cAMP, but not nerve growth factor or leukemia inhibitory factor, produced a rapid increase in GTPCH mRNA and protein levels; protein levels remained elevated during the entire treatment period while mRNA content declined rapidly between 10 and 24 h. Treatment with 8Br‐cAMP did not significantly modify the stability of GTPCH mRNA but did increase GTPCH transcription as determined by transient transfection assays of a luciferase reporter construct containing 1171 bp of human GTPCH 5′‐flanking sequence. Cis‐acting elements required for maximal basal and cAMP‐dependent transcription were localized by deletion analysis to the 146 bp proximal promoter. DNase I footprint analysis of the proximal promoter using SK‐N‐BE(2)M17 nuclear extracts identified two protein binding domains: one an upstream Sp1‐like site and the other a combined CRE‐Sp1‐CCAAT‐box element. EMSA and supershift assays demonstrated that the combined CRE‐Sp1‐CCAAT‐box element recruits ATF‐2 and NF‐Y but not Sp1–4 or Egr‐1–3. NF‐Y binding was confirmed using pure recombinant human NF‐Y protein. Transcription of the human GTPCH gene in human SK‐N‐BE(2)M17 cells is thus enhanced by cAMP acting through regulatory elements located in the proximal promoter and may involve the transcription factors NF‐Y and ATF‐2.
In vivo activation of N‐methyl‐d‐aspartate receptors in the rat hippocampus increases prostaglandin E2 extracellular levels and triggers lipid peroxidation through cyclooxygenase‐mediated mechanisms
Authors: Pepicelli O. , Fedele E. , Bonanno G. , Raiteri M. , Ajmone‐Cat M. A. , Greco A. , Levi G. , Minghetti L. 
Published: March 2003

AbstractCyclooxygenases (COX) are a family of enzymes involved in the biosynthesis of prostaglandin (PG) and thromboxanes. The inducible enzyme cyclooxygenase‐2 (COX‐2) is the major isoform found in normal brain, where it is constitutively expressed in neurons and is further up‐regulated during several pathological events, including seizures and ischaemia. Emerging evidence suggests that COX‐2 is implicated in excitotoxic neurodegenerative phenomena. It remains unclear whether PGs or other products associated to COX activity take part in these processes. Indeed, it has been suggested that reactive oxygen species, produced by COX, could mediate neuronal damage. In order to obtain direct evidence of free radical production during COX activity, we undertook an in vivo microdialysis study to monitor the levels of PGE2 and 8‐epi‐PGF2α following infusion of N‐methyl‐d‐aspartate (NMDA). A 20‐min application of 1 mm NMDA caused an immediate, MK‐801‐sensitive increase of both PGE2 and 8‐epi‐PGF2α basal levels. These effects were largely prevented by the specific cytosolic phospholipase A2 (cPLA2) inhibitor arachidonyl trifluoromethyl ketone (ATK), by non‐ selective COX inhibitors indomethacin and flurbiprofen or by the COX‐2 selective inhibitor NS‐398, suggesting that the NMDA‐evoked prostaglandin synthesis and free radical‐mediated lipid peroxidation are largely dependent on COX‐2 activity. As several lines of evidence suggest that prostaglandins may be potentially neuroprotective, our findings support the hypothesis that free radicals, rather than prostaglandins, mediate the toxicity associated to COX‐2 activity.
The mutation of two amino acid residues in the N‐terminus of tyrosine hydroxylase (TH) dramatically enhances the catalytic activity in neuroendocrine AtT‐20 cells
Authors: Nakashima Akira , Kaneko Yoko S. , Mori Keiji , Fujiwara Kentaro , Tsugu Toshimitsu , Suzuki Takahiro , Nagatsu Toshiharu , Ota Akira 
Published: March 2003

AbstractThe sequence Arg37‐Arg38 of tyrosine hydroxylase (TH) is known to play a significant role in the feedback inhibition by the end product DA. To clarify how deeply the sequence Arg37‐Arg38 and the phosphorylated Ser40 of human TH type 1 (hTH1) are involved in the regulation of this feedback inhibition in mammalian cells, we generated the following mutants: (i) RR‐GG, Arg37‐Arg38 replaced by Gly37‐Gly38; (ii) RR‐EE, Arg37‐Arg38 replaced by Glu37‐Glu38; (iii) S40D, Ser40 replaced by Asp40; and (iv) S40A, Ser40 replaced by Ala40. In a cell‐free system, the level of the DA inhibition of the RR‐EE mutant enzyme was to the same or smaller degree than that of the phosphorylation‐mimicking S40D. Next, AtT‐20 neuroendocrine cells were transfected with wild‐type and mutated TH genes because these cells were earlier shown to be capable of fully converting L‐3,4‐dihydroxyphenylalanine into DA, whereby the catalytic activity of TH would be expected to be inhibited by the end product DA accumulating in the cells. The level of DA accumulation in AtT‐20 cells expressing the TH gene was in the order: RR‐EE > S40D > S40A = RR‐GG > wild‐type, which was in accordance with the observations for the cell‐free system. These results suggest that the sequence Arg37‐Arg38 of hTH1 is a more potent determinant of the efficient production of DA in mammalian cells than is the phosphorylated Ser40‐hTH1.
Native group‐III metabotropic glutamate receptors are coupled to the mitogen‐activated protein kinase/phosphatidylinositol‐3‐kinase pathways
Authors: Iacovelli L. , Bruno V. , Salvatore L. , Melchiorri D. , Gradini R. , Caricasole A. , Barletta E. , De Blasi A. , Nicoletti F. 
Published: March 2003

AbstractWe used cultured cerebellar granule cells to examine whether native group‐III metabotropic glutamate (mGlu) receptors are coupled to the mitogen‐activated protein kinase (MAPK) and phosphatidylinositol‐3‐kinase (PI‐3‐K) pathways. Cultured granule cells responded to the group‐III mGlu receptor agonist, L‐2‐amino‐4‐phosphonobutanoate (l‐AP4), with an increased phosphorylation and activity of MAPKs (ERK‐1 and ‐2) and an increased phosphorylation of the PI‐3‐K target, protein kinase B (PKB/AKT). These effects were attenuated by the group‐III antagonists, α‐methyl‐serine‐O‐phosphate (MSOP) and (R,S)‐α‐cyclopropyl‐4‐phosphonophenylglycine (CPPG), or by pretreatment of the cultures with pertussis toxin. l‐AP4 also induced the nuclear translocation of β‐catenin, a downstream effector of the PI‐3‐K pathway. To assess the functional relevance of these mechanisms we examined the ability of l‐AP4 to protect granule cells against apoptosis by trophic deprivation, induced by lowering extracellular K+ from 25 to 10 mm. Neuroprotection by l‐AP4 was attenuated by MSOP and abrogated by the compounds PD98059 and UO126, which inhibit the MAPK pathway, or by the compound LY294002, which inhibits the PI‐3‐K pathway. Taken together, these results show for the first time that native group‐III mGlu receptors are coupled to MAPK and PI‐3‐K, and that activation of both pathways is necessary for neuroprotection mediated by this particular class of receptors.
Quantitative changes in mRNA expression of glutamate receptors in the rat peripheral and central vestibular systems following hypergravity
Authors: Uno Yoshihiro , Horii Arata , Uno Atsuhiko , Fuse Yuka , Fukushima Munehisa , Doi Katsumi , Kubo Takeshi 
Published: March 2003

AbstractIn order to investigate the mechanisms responsible for adaptation to altered gravity, we assessed the changes in mRNA expression of glutamate receptors in vestibular ganglion cells, medial vestibular nucleus, spinal vestibular nucleus/lateral vestibular nucleus, cerebellar flocculus, and uvula/nodulus from rats exposed to hypergravity for 2 h to 1 week using real‐time quantitative RT‐PCR methods. The mRNA expression of GluR2 and NR1 receptors in the uvula/nodulus and NR1 receptors in the medial vestibular nucleus increased in animals exposed to 2 h of hypergravity, and it decreased gradually to the control level. The mRNA expression of GluR2 receptors in vestibular ganglion cells decreased in animals exposed to 1 week of hypergravity. Neither the metabotropic glutamate receptor 1 nor δ2 glutamate receptor in flocculus and uvula/nodulus was affected by a hypergravity load for 2 h to 1 week. It is suggested that the animals adapted to the hypergravity by enhancing the cerebellar inhibition of the vestibular nucleus neurons through activation of the NR1 and GluR2 receptors on the Purkinje cells in uvula/nodulus especially at the early phase following hypergravity. In the later phase following hypergravity, the animals adapted to the hypergravity by reducing the neurotransmission between the vestibular hair cells and the primary vestibular neurons via down‐regulation of the postsynaptic GluR2 receptors in the vestibular periphery.
Interferon‐β activates multiple signaling cascades in primary human microglia
Authors: Kim Mee‐Ohk , Si Qiusheng , Zhou Jian Nian , Pestell Richard G. , Brosnan Celia F. , Locker Joseph , Lee Sunhee C. 
Published: March 2003

AbstractMicroglia, the resident brain macrophages, are the principal cells involved in the regulation of inflammatory and antimicrobial responses in the CNS. Interferon‐β (IFNβ) is an antiviral cytokine induced by viral infection or following non‐specific inflammatory challenges of the CNS. Because of the well‐known anti‐inflammatory properties of IFNβ, it is also used to treat multiple sclerosis, an inflammatory CNS disease. Despite the importance of IFNβ signaling in CNS cells, little has been studied, particularly in microglia. In this report, we investigated the molecular mechanisms underlying IFNβ‐induced β‐chemokine expression in primary human fetal microglia. Multiple signaling cascades are activated in microglia by IFNβ, including nuclear factor‐κB (NF‐κB), activator protein‐1 (AP‐1) and Jak/Stat. IFNβ induced IκBα degradation and NF‐κB (p65:p50) DNA binding. Inhibition of NF‐κB by either adenoviral transduction of a super repressor IκBα, or an antioxidant inhibitor of NF‐κB reduced expression of the β‐chemokines, regulated upon activation, normal T‐cell expressed and secreted (RANTES) and macrophage inflammatory protein (MIP)‐1β. IFNβ also induced phosphorylation of extracellular signal‐regulated kinase (ERK) mitogen‐activated protein kinase, and the MAP kinase kinase 1 (MEK1) inhibitor PD98059 dose‐dependently inhibited β‐chemokine mRNA and protein expression. PD98059 did not inhibit NF‐κB binding, demonstrating that ERK was not responsible for NF‐κB activation. Two downstream targets of ERK were identified in microglia: AP‐1 and Stat1. IFNβ induced AP‐1 nuclear binding activity in microglia and this was suppressed by PD98059. Additionally, IFNβ induced Stat1 phosphorylation at both tyrosine 701 (Y701) and serine 727 (S727) residues. S727 phosphorylation of Stat1, which is known to be required for maximal transcriptional activation, was inhibited by PD98059. Our results demonstrating multiple signaling cascades initiated by IFNβ in primary human microglia are novel and have implications for inflammatory and infectious diseases of the CNS.
The binding of prion proteins to serum components is affected by detergent extraction conditions
Authors: Shaked Yuval , Engelstein Roni , Gabizon Ruth 
Published: March 2003

AbstractAs many GPI anchored proteins, PrPC and its abnormal conformer PrPSc, are inserted into membrane microdomains known as rafts. Upon raft disruption, PrPC becomes soluble, while PrPSc aggregates into insoluble structures. It was recently published that, as opposed to PrPC, PrPSc, as well as its protease resistant core PrP27‐30, can bind specifically to plasminogen and other serum components. These findings were suggested to have important physiological implications in transmissible spongiform encephalopathies (TSE) diagnosis and pathogenesis. In this work, we show that the binding of PrPSc or PrP 27–30 to serum proteins occurs only at specific detergent combinations, in which disease associated PrPs are present in aggregated structures. At detergent conditions in which rafts are intact, it is actually PrPC. that binds to blood proteins, albeit not directly, but through neighboring rafts components. Our results therefore indicate that the binding of PrPSc to blood components has no physiological relevance.
GABA is toxic for mouse striatal neurones through a transporter‐mediated process
Authors: Maus Marion , Glowinski Jacques , Premont Joel 
Published: March 2003

AbstractIn the present study, GABA was shown to induce a necrotic neuronal death in cultured striatal neurones from mouse embryos. This effect did not depend on the activation of GABAA, GABAB or GABAC receptors as it was neither antagonized by bicuculline, saclofen or picrotoxin, respectively, nor reproduced by the GABA receptor agonists, muscimol and baclofen. Excluding the participation of glutamate, GABA neurotoxicity persisted in the presence of either the antagonists of ionotropic and metabotropic glutamate receptors or glutamate pyruvate transaminase, which induces an immediate catabolism of glutamate. A GABA transport‐associated process is involved in GABA neurotoxicity as nipecotic acid and NO 711, two inhibitors of the high‐affinity neuronal GABA transporters (GAT‐1, in particular), completely prevented the neurotoxic effect of GABA. The activation of a subset of G proteins is also implicated in the GABA transport‐mediated neuronal death as GABA neurotoxicity was completely suppressed when striatal neurones were pre‐treated with pertussis toxin. Further demonstrating the specificity of this neurotoxic process, GABA‐induced neurotoxicity was not observed in cortical neurones which, in contrast to striatal neurones, are largely represented by glutamatergic neurones. In conclusion, our study suggests that glutamate is not the sole neurotransmitter that can be responsible for brain damage and that GABA neurotoxicity involves both GABA transport and G protein transduction pathways.
Identification and functional characterization of nadrin variants, a novel family of GTPase activating protein for rho GTPases
Authors: Furuta Birei , Harada Ayako , Kobayashi Yoko , Takeuchi Ken‐ichi , Kobayashi Tetsuyuki , Umeda Masato 
Published: March 2003

AbstractNadrin is a GTPase‐activating protein (GAP) for the rho family of GTPases that controls Ca2+‐dependent exocytosis in nerve endings. In this study, three novel splice variants of nadrin were identified and the variants were designated as nadrin‐102, ‐104, ‐116 and ‐126 according to their relative molecular masses. All nadrin variants share the GAP domain, coiled‐coil domain, serine/threonine/proline‐rich domain, SH3‐binding motif, and a successive repeat of 29 glutamines. Tissue distribution analyses using polyclonal antibodies that can discriminate each variant showed that the expression of nadrin‐102, ‐104 and ‐116 was dominant in neuronal tissues and correlates well with the differentiation of neurons while nadrin‐126 was strongly expressed in embryonic brain. Expression of nadrin‐116 in PC12 cells strongly inhibited NGF‐dependent neurite outgrowth and this effect was dependent on its GAP activity. In contrast, no significant effect on either cell morphology or neurite outgrowth was observed with other variants. All variants showed punctate appearance throughout the cytoplasm, while the 66‐kDa carboxyl‐terminal fragment of nadrin‐102 and/or nadrin‐116 was localized to the nucleus and its nuclear translocation was accelerated by NGF‐induced differentiation of the cells. These results suggested that nadrin variants are different in their ability to regulate rho‐mediated signaling and that, in addition to being aGTPase‐activating protein, nadrin‐102 and ‐116 have otherdistinct functions in the nucleus of the cell, implying apossible role in the cross‐talk between the cytoskeleton andthe nucleus.
Okadaic acid disrupts synaptic vesicle trafficking in a ribbon‐type synapse
Authors: Guatimosim Cristina , Hull Court , Von Gersdorff Henrique , Prado Marco A. M. 
Published: March 2003

AbstractProtein phosphorylation plays an essential role in regulating synaptic transmission and plasticity. However, regulation of vesicle trafficking towards and away from the plasma membrane is poorly understood. Furthermore, the extent to which phosphorylation modulates ribbon‐type synapses is unknown. Using the phosphatase inhibitor okadaic acid (OA), we investigated the influence of persistent phosphorylation on vesicle cycling in goldfish bipolar cells. We followed uptake of FM1‐43 during vesicle recycling in control and OA‐treated cells. FM1‐43 fluorescence spread to the center of control synaptic terminals after depolarization elicited Ca2+ influx. However, OA (1–50 nm) impaired this spatial spread of FM1‐43 in a dose‐dependent manner. Capacitance measurements revealed that OA (50 nm) did not modify either the amount or kinetics of exocytosis and endocytosis evoked by depolarizing pulses. The extremely low concentrations of OA (1–5 nm) sufficient to observe the inhibition of vesicle mobility implicate phosphatase 2A (PP2A) as a major regulator of vesicle trafficking after endocytosis. These results contrast with those at the neuromuscular junction where OA enhances lateral movement of vesicles between distinct vesicle clusters. Thus, our results suggest that phosphatases regulate vesicle translocation at ribbon synapses in a different manner than conventional active zones.
1‐Methyl‐4‐phenylpridinium (MPP+)‐induced functional run‐down of GABAA receptor‐mediated currents in acutely dissociated dopaminergic neurons
Authors: Wu Jie , Chan Piu , Schroeder Katherine M. , Ellsworth Kevin , Partridge L. Donald L. 
Published: March 2003

AbstractWe have evaluated GABAA receptor function during treatment of 1‐methyl‐4‐phenylpridinium (MPP+) using patch‐clamp perforated whole‐cell recording techniques in acutely dissociated dopaminergic (DAergic) neurons from rat substantia nigra compacta (SNc). γ‐Aminobutyric acid (GABA), glutamate or glycine induced inward currents (IGABA, IGlu, IGly) at a holding potential (VH) of −45 mV. The IGABA was reversibly blocked by the GABAA receptor antagonist, bicuculline, suggesting that IGABA is mediated through the activation of GABAA receptors. During extracellular perfusion of MPP+ (1–10 μm), IGABA, but neither IGlu nor IGly, declined (termed run‐down) with repetitive agonist applications, indicating that the MPP+‐induced IGABA run‐down occurred earlier than IGly or IGlu under our experimental conditions. The MPP+‐induced IGABA run‐down can be prevented by a DA transporter inhibitor, mazindol, and can be mimicked by a metabolic inhibitor, rotenone. Using conventional whole‐cell recording with different concentrations of ATP in the pipette solution, IGABA run‐down can be induced by decreasing intracellular ATP concentrations, or prevented by supplying intracellular ATP, indicating that IGABA run‐down is dependent on intracellular ATP concentrations. A GABAA receptor positive modulator, pentobarbital (PB), potentiated the declined IGABA and eliminated IGABA run‐down. Corresponding to these patch‐clamp data, tyrosine hydroxylase (TH) immunohistochemical staining showed that TH‐positive cell loss was protected by PB during MPP+ perfusion. It is concluded that extracellular perfusion of MPP+ induces a functional run‐down of GABAA receptors, which may cause an imbalance of excitation and inhibition of DAergic neurons.