bluuebunny/crossref_metadata_2025 huggingface dataset:
Consumer education: educational considerations and perspectives
Authors: Benn Jette
Published: March 2003

This paper examines questions concerning consumer education in relation to consumption and household management. It is based partly on literature studies and partly on a current pilot study, also on studies carried out in the classroom and developmental work in schools and on teacher training courses. The pilot study on consumer education is being carried out in Denmark and is funded by the Danish Ministry of Business Affairs. Another part of the study concerns a qualitative investigation of pupils’ understandings of consumption and its meaning in their lives, but this is not reported here. The key research questions relate to the way in which the young consumer is educated, both formally and informally, and what the possibilities and perspectives are for consumer education. Introductory research is discussed, followed by a presentation and discussion of key issues for consumer education, such as household management, consumption, home economics and education. Finally, three examples are described and discussed which demonstrate how the advocated principles of consumer education and empowerment can be put into practice. These examples are based on developmental work carried out in lower secondary schools and teacher training courses.
Foods produced using biotechnology: how does the law protect consumers?
Authors: Emirogˇlu Haluk
Published: March 2003

This paper addresses the following subjects: biotechnology and consumers, concern about risks, consumer acceptance, labelling of foods produced using biotechnology, the legal approach to consumer protection, and consumer protection policies relating to biotechnology products in the European Union, the United States, Turkey and global institutions such as the Convention for Biological Diversity (CBD) and the World Trade Organisation (WTO). It is likely that biotechnology will gain ground much more rapidly in the twenty‐first century than in the past. Despite rapid, detailed and precise advances in gene technology, its applications have not been the received with a great deal of consumer enthusiasm. Consumers have approached genetically modified foods with considerable apprehension and opposition. Consumer concerns about bioengineered food products focus on the questions of human health, environmental and social risks and benefits. The most important stages in the process of marketing new foods produced using biotechnology are to demonstrate user need and consumer acceptance. Generally, the technical complexity of biotechnology makes it difficult for consumers to understand details of the product and the specific attributes of biotechnology applications. Scientific uncertainty, the nature of consumer concerns and general reluctance to accept biotechnology products, increase the importance of consumer protection. Legal protection is a very important factor in the solution of new social problems related to technological advances. More specifically, consumer and environmental law support consumer protection related to foods produced with biotechnology. The basic principles of consumer law can be re‐formulated as consumer rights. Environmental law is a new phenomenon, but precautionary principles and public participation in decision‐making for environmental law are relevant to consumer protection relating to bioengineered food products.
Home economists’ perceptions of international development
Authors: McGregor Sue L.T.
Published: March 2003

Little is known about home economists’ perceptions of international development (ID). This paper offers some insights about this issue gained from an interpretative, thematic analysis of a very small sample of participants who attended the 1996 International Federation of Home Economics Congress. The analysis suggests inconsistencies in how home economists understand ID and what is seen to constitute ID activities, a lack of consensus about the meaning of development work, a lack of certainty about the difference between criticism and critique and concern for the imposition of western ideology on southern countries. Seven themes for future research are offered to help gain a better understanding of how home economists perceive ID including: (1) the role of participatory action research, critical theory, science and critical reflective practice in ID; (2) meanings attached to the concepts of international, development and economic growth; (3) the necessity of positioning an ID philosophy in practice, curricula, research and policy; and (4) perceptions of what constitutes development activities at home and abroad.
Adolescents’ brand sensitivity in apparel: influence of three socialization agents
Authors: Lachance Marie J. , Beaudoin Pierre , Robitaille Jean
Published: March 2003

Wearing clothes with prestigious brand names seems to be very important for adolescents. This phenomenon was studied in the context of consumer socialization by examining the influence of three socialization agents, namely parents, peers and TV, on the development of French Canadian adolescents’ brand sensitivity and their relative importance. Controlling for socio‐economic variables, multiple regression analyses were conducted separately for boys and for girls. For both genders, brand sensitivity is related to peer influence. Girls’ brand sensitivity is related to the importance fathers give to clothing brands. TV exposure is not related to adolescents’ brand sensitivity. For boys and girls, peers represent the most important predictor of this consumer socialization. The results are discussed in the light of social and economic pressures and family relationships.
A microbiological survey of communal kitchens used by undergraduate students
Authors: Sharp Kay , Walker Harriet
Published: March 2003

The majority of food poisoning cases occur in the domestic environment as a result of inadequate hygiene practices. The possibility of food safety errors may be increased in domestic kitchens that are shared. However, there is very little information concerning the hygiene of these kitchens. This study investigates the microbial load of key sites in six student communal kitchens. In addition, hygiene was evaluated visually and questionnaires were used to assess the hygiene practices of the kitchen users. Results show that visual hygiene assessments are not a good indicator of microbial contamination, which, in this study, reveal poor levels of hygiene. Food safety errors were commonly made by users of the kitchens and their food hygiene practices suggest limited food safety knowledge and/or an absence of feelings of responsibility for the hygiene standard of the kitchen.
A comparison and evaluation of research methods used in consumer food safety studies
Authors: Redmond Elizabeth C. , Griffith Christopher J.
Published: March 2003

Worldwide incidence of food‐borne disease has increased in recent years and data suggest that inadequate food‐handling behaviour in the domestic environment may be an important factor. As a consequence of this, research into aspects of consumer food safety has been undertaken, especially in the UK and USA. The overall aims of conducting such research have been to investigate aspects of consumer food safety behaviour and to utilize information in the development of effective food safety education initiatives. In the past 25 years, 87 consumer food safety studies have been undertaken using different research methodologies; 75% utilized survey techniques (questionnaires and interviews), 17% were based on direct observation, and 8% utilized focus groups. The advantages and disadvantages of the different research methods used are discussed. Similarly, different forms of reliability and validity have been considered in the context of each research method used. A comparison of results from consumer food safety studies has shown that use of different research designs and approaches has resulted in differences in the findings about consumer food safety behaviour. Survey responses have provided a more optimistic portrayal of consumer food safety behaviour than data obtained from focus groups and direct observation. Although consumers have demonstrated knowledge, positive attitudes and intentions to implement safe practices, substantially larger proportions of consumers have been observed to implement frequent malpractices. This suggests that observational data provide the most reliable information denoting consumers’ actual food safety behaviour and should be used preferentially with risk‐based data for the design of communication strategies.
Brakes to organic market enlargement in Spain: consumers’ and retailers’ attitudes and willingness to pay
Authors: Sanjuán Ana I. , Sánchez Mercedes , Gil José M. , Gracia Azucena , Soler Francisco
Published: March 2003

In Spain, consumption of organic products has not kept pace with production. Up till now, foreign markets have been a natural destination for excess supply. However, world trade liberalization might cause important commercial problems to Spanish producers that could be partially solved by enlarging the domestic market. The goal of this paper is to assess the opportunity for such enlargement focusing on two main aspects: consumers’ and retailers’ attitudes and willingness to pay for organic products. Concerns about health, natural diets or environmental issues could stimulate consumption, while retailing dynamism and competition to gain new market segments might favour distribution. Both aspects are investigated through two surveys addressed to consumers and retailers in two Spanish towns. The results confirm that only a small proportion of consumers and distributors show attitudes that might favour demand expansion. The most sensitized segments are willing to pay more for organic products, but this premium is still very far from the prevailing gap between conventional and organic food products.
Effect of technological parameters on the characteristics of kasseri cheese made from raw or pasteurized ewes’ milk
Authors: Moatsou Golfo , Kandarakis Ioannis , Moschopoulou Ekaterini , Anifantakis Emmanouil , Alichanidis Efstathios
Published: March 2003

Two groups of kasseri cheese (pasta filata type) were manufactured from raw or pasteurized ewes’ milk, without starter cultures. Cheeses of each group were divided into two subgroups: the first was ripened and stored at 4°C and packaged in plastic film; the second ripened and stored at 15°C and coated with paraffin wax. Milk pasteurization and technological parameters had a significant effect on the pH ( P < 0.05), while only technological parameters had an effect on the total solids content. At day 120, the range of mean cfu/g counts for the mesophilic aerobic flora was 9.5 × 107−1.4 × 108; for the thermophilic streptococci, the range was 2.6 × 107−7.6 × 107; and for the thermophilic bacilli, 9.8 × 106−1.7 × 107. Changes in the N fractions became significant after 30 days of ripening. For mature 120‐day‐old cheeses, the percentage of total N soluble at pH 4.6 was 22.7%–22.9% in raw milk cheeses and 19.0%–21.7% in pasteurized milk cheeses. The percentage of total N soluble at 12% TCA was 10.1%–12.2% in raw milk cheeses and 7.3%–11.5% in pasteurized milk cheeses; the percentages of total N soluble at 5% PTA were 3.1%–4.0% and 2.6%–3.6%, respectively. The residual αs‐casein percentages at day 120 ranged between 63% and 78% of the respective area at day 1; the residual β‐casein ranged between 67% and 75%. There were some characteristic differences in the reverse phase‐HPLC peptide profiles of the four cheeses. In general, the effect of the different ripening conditions was more pronounced in cheeses made from pasteurized milk.
Calcium Channels in the GABAergic Presynaptic Nerve Terminals Projecting to Meynert Neurons of the Rat
Authors: Rhee Jeong‐Seop , Ishibashi Hitoshi , Akaike Norio
Published: March 2003

Abstract : Effects of selective Ca2+ channel blockers on
GABAergic inhibitory postsynaptic currents (IPSCs) were studied in the acutely
dissociated rat nucleus basalis of Meynert (nBM) neurons attached with nerve
endings, namely, the “synaptic bouton” preparation, and in the
thin slices of nBM, using nystatin perforated and conventional whole‐cell
patch recording modes, respectively. In the synaptic bouton preparation,
nicardipine (3 × 10‐6M) and ω‐conotoxin‐MVIIC
(3 × 10‐6M) reduced the frequency of spontaneous
postsynaptic currents by 37 and 22%, respectively, whereas
ω‐conotoxin‐GVIA had no effect. After blockade of L‐ and P/Q‐type
Ca2+ channels, successive removal of Ca2+ from external
solution had no significant effect on the residual spontaneous activities,
indicating that N‐, R‐, and T‐type Ca2+ channels are not involved
in the spontaneous GABA release. Thapsigargin, but not ryanodine, increased
the frequency of spontaneous IPSCs in both the synaptic bouton and slice
preparations, suggesting the partial contribution of the intracellular
Ca2+ storage site to the spontaneous GABA release. In contrast,
ω‐conotoxin‐GVIA (3 × 10‐6M) and
ω‐conotoxin‐MVIIC (3 × 10‐6M) suppressed the
evoked IPSCs by 31 and 37%, respectively, but nicardipine produced no
significant effect. The residual evoked currents were abolished in
Ca2+‐free external solution but not in the external solution
containing 10‐5M Ni2+, suggesting the
involvement of N‐, P/Q‐, and R‐type Ca2+ channels but not L‐ and
T‐type ones in the evoked IPSCs. Neither thapsigargin nor ryanodine had any
significant effects on the evoked IPSCs. It was concluded that Ca2+ channel subtypes responsible for spontaneous transmitter release are different from those mediating the transmitter release evoked by nerve stimulation.
Synergism of Nitric Oxide and Iron in Killing the Transformed Murine Oligodendrocyte Cell Line N20.1
Authors: Boullerne A. I. , Nedelkoska L. , Benjamins J. A.
Published: March 2003

Abstract : Nitric oxide (NO) produced in inflammatory lesions may
play a major role in the destruction of oligodendrocytes in multiple sclerosis
and experimental allergic encephalomyelitis. The transformed murine
oligodendroglial line N20.1 is much more resistant than primary
oligodendrocytes to killing by the NO generator
S‐nitroso‐N‐acetyl‐DL‐penicillamine (SNAP). This observation
prompted investigation of the mechanisms leading to cell death in the N20.1
cells and comparison of SNAP with another NO donor, sodium nitroprusside
(SNP). We observed that N20.1 cells were 30 times more sensitive to SNP than
to SNAP. The specific NO scavenger
2‐phenyl‐4,4,5,5‐tetramethylimidazoline‐1‐oxyl‐3‐oxide (PTIO) protected
against SNP only, not against SNAP. However, dithiothreitol protected against
both SNAP and SNP, indicating that S‐nitrosylation of cysteines plays
a major role in the cytotoxicity of both NO donors. We did not observe any
formation of peroxynitrite or increase of Ca2+ concentration with either SNAP or SNP, thus excluding their involvement in the mechanisms leading to N20.1 cell death. Based on two observations, (a) potentiation of the cytotoxic effect of SNP when coincubated with ferricyanide or ferrocyanide, but not sodium cyanide, and (b) protection by deferoxamine, an iron cyanide chelator, we conclude that the greater sensitivity of N20.1 cells to SNP compared with SNAP is due to synergism between NO released and the iron cyanide portion of SNP, with the cyanide accounting for very little of the cytotoxicity. Finally, SNP but not SNAP induces some apoptosis, as shown by DNA laddering and protection by a caspase‐3 inhibitor. These results suggest that low levels of NO in combination with increased iron content lead to apoptotic cell death rather than the necrotic cell death seen with higher levels of NO generated by SNAP.
Molecular Cloning and Expression of a Full‐Length cDNA Encoding Acetylcholinesterase in Optic Lobes of the Squid
Authors: Talesa Vincenzo , Grauso Marta , Arpagaus Martine , Giovannini Elvio , Romani Rita , Rosi Gabriella
Published: March 2003

Abstract : Acetylcholinesterase cDNA was cloned by screening a
library from Loligo opalescens optic lobes ; cDNA sequence analysis
revealed an open reading frame coding for a protein of 610 amino acids that
showed 20‐41% amino acid identity with the acetylcholinesterases studied so
far. The characteristic structure of cholinesterase (the choline binding site,
the catalytic triad, and six cysteines that form three intrachain disulfide
bonds) was conserved in the protein. The heterologous expression of
acetylcholinesterase in COS cells gave a recovery of acetylcholinesterase
activity 20‐fold higher than in controls. The enzyme, partially purified by
affinity chromatography, showed molecular and kinetic features
indistinguishable from those of acetylcholinesterase expressed in vivo, which
displays a high catalytic efficiency. Both enzymes are true
acetylcholinesterase corresponding to phosphatidylinositol‐anchored
G2a dimers of class I, with a marked substrate
specificity for acetylthiocholine. The deduced amino acid sequence may explain
some particular kinetic characteristics of Loligo
acetylcholinesterase, because the presence of a polar amino acid residue
(S313) instead of a nonpolar one [F(288) in Torpedo] in the acyl pocket of the active site could justify the high substrate specificity of the enzyme, the absence of hydrolysis with butyrylthiocholine, and the poor inhibition by the organophosphate diisopropyl fluorophosphate.
Metabolic Impairment Induces Oxidative Stress, Compromises Inflammatory Responses, and Inactivates a Key Mitochondrial Enzyme in Microglia
Authors: Park Larry C. H. , Zhang Hui , Sheu Kwan‐Fu Rex , Calingasan Noel Y. , Kristal Bruce S. , Gordon Lindsay J. , Gibson Gary E.
Published: March 2003

Abstract: Microglial activation, oxidative stress, and dysfunctions in mitochondria, including the reduction of cytochrome oxidase activity, have been implicated in neurodegeneration. The current experiments tested the effects of reducing cytochrome oxidase activity on the ability of microglia to respond to inflammatory insults. Inhibition of cytochrome oxidase by azide reduced oxygen consumption and increased reactive oxygen species (ROS) production but did not affect cell viability. Azide also attenuated microglial activation, as measured by nitric oxide (NO*) production in response to lipopolysaccharide (LPS). It is surprising that the inhibition of cytochrome oxidase also diminished the activity of the α‐ketoglutarate dehydrogenase complex (KGDHC), a Krebs cycle enzyme. This reduction was exaggerated when the azide‐treated microglia were also treated with LPS. The combination of the azide‐stimulated ROS and LPS‐induced NO* would likely cause peroxynitrite formation in microglia. Thus, the possibility that KGDHC was inactivated by peroxynitrite was tested. Peroxynitrite inhibited the activity of isolated KGDHC, nitrated tyrosine residues of all three KGDHC subunits, and reduced immunoreactivity to antibodies against two KGDHC components. Thus, our data suggest that inhibition of the mitochondrial respiratory chain diminishes aerobic energy metabolism, interferes with microglial inflammatory responses, and compromises mitochondrial function, including KGDHC activity, which is vulnerable to NO* and peroxynitrite that result from microglial activation. Thus, activation of metabolically compromised microglia can further diminish their oxidative capacity, creating a deleterious spiral that may contribute to neurodegeneration.
Effect of GABA on Melatonin Content in Golden Hamster Retina
Authors: Jaliffa Carolina O. , Faillace María P. , Lacoste Francisco Firpo , Llomovatte Diego Weinberg , Sarmiento María I. Keller , Rosenstein Ruth E.
Published: March 2003

Abstract:The effect of GABA on melatonin content in vitro was studied in the golden hamster retina. GABA significantly increased melatonin levels in a dose‐dependent manner, its effect being reversed by a GABAAreceptor antagonist, bicuculline, but not by saclofen, a GABABantagonist. Moreover, an equimolar concentration of muscimol, a GABAAreceptor agonist, significantly increased retinal melatonin content, whereas baclofen, a GABABreceptor agonist, was ineffective. The darkness‐induced increase in melatonin content in vitro was inhibited by bicuculline, whereas saclofen was ineffective. Retinal GABA turnover rate was significantly higher at midnight than at midday. GABA significantly decreased cyclic AMP and increased cyclic GMP accumulation in the golden hamster retina. The effect of GABA on both nucleotide levels was reversed by bicuculline, but baclofen had no effect. Cyclic GMP analogues (i.e., 8‐bromoguanosine 3′,5′‐cyclic monophosphate and 2′‐O‐dibutyrylguanosine 3′,5′‐cyclic monophosphate) significantly increased retinal melatonin content in vitro. Taken together, these results support the hypothesis that GABA may be important for the “dark message” in the hamster retina.
A Chronic Stress that Impairs Reactivity in Rats Also Decreases Dopaminergic Transmission in the Nucleus Accumbens: A Microdialysis Study
Authors: Gambarana Carla , Masi Flavio , Tagliamonte Alessandro , Scheggi Simona , Ghiglieri Ombretta , Graziella De Montis Maria
Published: March 2003

Abstract: Chronic stress induces in rats a decreased reactivity toward noxious stimuli (escape deficit), which can be reverted by antidepressant treatments. The present study reports that this condition of behavioral deficit is accompanied by a decreased level of extracellular dopamine in the nucleus accumbens shell. To assess whether this finding was the result of a decreased release or of an enhanced removal of dopamine, we acutely administered cocaine, and 2 h later d‐amphetamine, to stressed and control rats. The increases in dopamine output observed in stressed animals after cocaine administration were significantly lower than those observed in control rats; whereas the total amount of dopamine released after d‐amphetamine administration was similar in both groups of rats. These data suggest a reduced activity of dopaminergic neurons as the possible mechanism underlying dopamine basal level reduction in stressed animals. It is interesting that the stress group showed a locomotor response to cocaine not different from control rats, thus suggesting a condition of sensitization to dopamine receptor stimulation. Imipramine administered daily concomitantly with stress exposure completely reverted the escape deficit condition of chronically stressed rats. Moreover, stressed rats treated with imipramine showed basal and cocaine stimulated levels of extraneuronal dopamine similar to those observed in control animals.
Modulation of Spontaneous and Stimulation‐Evoked Transmitter Release from Rat Sympathetic Neurons by the Cognition Enhancer Linopirdine: Insights into Its Mechanisms of Action
Authors: Kristufek Doris , Koth Gabriele , Motejlek Andrea , Schwarz Karin , Huck Sigismund , Boehm Stefan
Published: March 2003

Abstract: The mechanisms by which the cognition enhancer linopirdine may affect transmitter release were investigated in cultures of rat superior cervical ganglion neurons. Overflow of previously incorporated [3H]noradrenaline evoked by 10 μM UTP or 0.1 μM bradykinin was enhanced by linopirdine at ∼3 μM, overflow evoked by 25 mM K+, 100 μM nicotine, or 300 μM ATP was enhanced by linopirdine at ∼10 μM, and overflow due to 40 mM K+ or electrical field stimulation was not altered by linopirdine. Ba2+ (0.3 mM) augmented the same types of stimulation‐evoked overflow to a similar extent as linopirdine. K+ (25 mM), nicotine (100 μM), and ATP (300 μM) triggered transmitter release in a partially tetrodotoxin‐resistant manner, and the release‐enhancing action of linopirdine was lost in the presence of tetrodotoxin (1 μM). Linopirdine (10 μM) raised spontaneous tritium outflow and reduced currents through muscarinic K+ (KM) channels with a similar time course. The secretagogue action of linopirdine was concentration‐ and Ca2+‐dependent and abolished by tetrodotoxin (1 μM) or Cd2+ (100 μM). Linopirdine (10 μM) added to the partial inhibition of KM channels by 1 or 3 mM Ba2+ but not to the complete inhibition by 10 mM Ba2+. Likewise, the secretagogue action of 1 and 3 mM, but not that of 10 mM, Ba2+ was enhanced by linopirdine. These results indicate that linopirdine facilitates and triggers transmitter release via blockade of KM channels and suggest that these K+ channels are located at neuronal somata rather than at presynaptic sites.
Prolonged Inhibition of Glutamate Reuptake Down‐Regulates NMDA Receptor Functions in Cultured Cerebellar Granule Cells
Authors: Cebers Gvido , Cebere Aleta , Wägner Anna , Liljequist Sture
Published: March 2003

Abstract: In the present study, we have examined the effects of prolonged (up to 72 h) inhibition of high‐affinity glutamate reuptake by L‐trans‐pyrrolidine‐2,4‐dicarboxylate (PDC; 100 γM) on glutamate receptor functions in primary cultures of rat cerebellar granule neurons. This was done by comparing the effects of various glutamate receptor agonists on neuronal 45Ca2+ uptake, free cytoplasmic Ca2+ concentration ([Ca2+]i), and cell viability. We also determined the parameters of [3H]MK‐801 binding as well as the expression of the NMDAR1 subunit protein in control and PDC‐exposed cultures. The blockade of glutamate reuptake by PDC led to a gradual increase of ambient glutamate to concentrations that are neurotoxic when applied acutely to control cells. In PDC‐exposed cells, however, the acute glutamate‐induced NMDA receptor‐mediated calcium fluxes were strongly diminished and no toxicity was observed. The down‐regulation of the functional effects of glutamate was dependent on the duration of PDC exposure and was accompanied by a reduced NMDAR1 subunit expression and decreased [3H]MK‐801 binding, indicative of a pronounced structural rearrangement of NMDA receptors. The possibility that the decrease of NMDA glutamate receptor sensitivity can be explained on the basis of a reduced density or altered subunit composition of NMDA receptors is discussed.
Estrogen Hormones Reduce Lipid Peroxidation in Cells and Tissues of the Central Nervous System
Authors: Vedder H. , Anthes N. , Stumm G. , Würz C. , Behl C. , Krieg J.‐C.
Published: March 2003

Abstract: Effects of estrogen hormones on lipid peroxidation (LPO)
were examined in rat brain homogenates (RBHs), hippocampal HT 22 cells, rat
primary neocortical cultures, and human brain homogenates (HBHs).
Dose‐response curves indicated half‐maximal effective concentrations
(EC50) of 5.5 and 5.6 mM for iron‐induced LPO in RBHs and
HT 22 homogenates. Incubation of living rat primary neocortical cultures with
iron resulted in an EC50 of 0.5 mM, whereas culture
homogenates showed an EC50 of 1.2 mM. Estrogen hormones
reduced LPO in all systems: In RBHs, estrone inhibited iron‐induced LPO to
74.1 ± 5.8% of control levels (17β‐estradiol: 71.3 ± 0.1%)
at a concentration of 10 μM. In hippocampal HT 22 cell
homogenates, levels of LPO were reduced to 74.8 ± 5.5% by estrone and
to 47.8 ± 6.2% by 17β‐estradiol. In living neocortical cultures,
17β‐estradiol decreased iron‐induced LPO to 79.2 ± 4.8% and
increased the survival of cultured neuronal cells. Of the other steroid
compounds tested (corticosterone, progesterone, testosterone), only
progesterone decreased LPO in HT 22 cell homogenates. In HBHs, LPO was
dose‐dependently increased by iron concentrations from 2.7 to 6.0 mM.
Incubation with estrogens resulted in a dose‐dependent inhibition of LPO to
53.89 ± 8.6% with 10 μM 17β‐estradiol, whereas estrone failed to affect iron‐induced LPO to a significant extent. Nonestrogenic steroids, including hydrocortisol, did not show significant effects on LPO in HBHs.
Translocation and Down‐Regulation of Protein Kinase C‐α, ‐β, and ‐γ Isoforms During Ischemia‐Reperfusion in Rat Brain
Authors: Harada Kazuki , Maekawa Tsuyoshi , Shama Kazi Mohammed Abu , Yamashima Tetsumori , Yoshida Ken‐ichi
Published: March 2003

Abstract: We investigated the distribution of protein kinase C (PKC)
isoforms in the subcellular fractions (P1, 1,000‐g pellet; P2,
10,000‐g pellet; P3, 100,000‐g pellet; S, 100,000‐g supernatant) of rat forebrain after ischemia or reperfusion by immunoblotting. PKC‐δ and ‐ε isoforms were predominant in the P2 (synaptosome‐rich) fraction, whereas PKC‐α, ‐β, ‐γ, ‐ε, and ‐ζ isoforms were rich in the S (cytosolic) fraction. With time of ischemia (5‐30 min), PKC‐α, ‐β, and ‐γ translocated to the P2 and P3 fractions, whereas reperfusion for 60 min after 30 min of ischemia reduced PKC‐β activity greatly and PKC‐α and ‐γ activities to a lesser extent. There was no redistribution of PKC‐δ, ‐ε, and ‐ζ after ischemia or reperfusion. A calpain inhibitor, acetylleucylleucylnorleucinal, inhibited the down‐regulation of PKC‐β, through intravenous injection. The PKC translocation to the P2 fraction was accompanied by their dephosphorylation, transition of PKC‐α from dimer to trimer, and the decrease in activity. These data show that PKC‐α, ‐β, and ‐γ isoforms translocate chiefly to the synaptosome in ischemic brain in association with the dephosphorylation, multimeric change, and inactivation, followed by the proteolysis of PKC‐β by calpain after postischemic reperfusion.
Analysis ofcis‐Acting Sequences from the Myelin Oligodendrocyte Glycoprotein Promoter
Authors: Jaquet V. , Pfend G. , Tosic M. , Matthieu J.‐M.
Published: March 2003

Abstract:Myelin oligodendrocyte glycoprotein (MOG), a minor component of the myelin sheath, appears to be implicated in the late events of CNS myelinogenesis. To investigate the transcriptional regulation of MOG, 657 bp of the 5′‐flanking sequence of the murine MOG gene, previously shown to induce the highest level of transcription in an oligodendroglial cell line, was analyzed by in vitro footprinting and electrophoretic mobility shift assays. This region contains at least three sites that contact nuclear proteins in vitro. Each region described in this study binds specific nuclear proteins and enhances transcription in the OLN‐93 glial cell line. More specifically, a region located at position ‐93 to ‐73 bp, which displays 100% homology in mouse and human MOG promoters, presents distinct binding affinities between brain and liver nuclear proteins. The results obtained by supershift assay and site‐directed mutagenesis reveal that this region contains an essential positive element (TGACGTGG) related to the cyclic AMP‐responsive element CREB‐1 and are additional evidence for the involvement of the cyclic AMP transduction pathway in oligodendrocyte development.
Orphanin FQ/Nociceptin Modulation of Mesolimbic Dopamine Transmission Determined by Microdialysis
Authors: Murphy Niall P. , Maidment Nigel T.
Published: March 2003

Abstract: Orphanin FQ has been reported to suppress extracellular dopamine levels in the nucleus accumbens after intracerebroventricular administration. This study sought to provide evidence for an intra‐ventral tegmental site of action for this effect using a dual‐probe microdialysis experimental design. Orphanin FQ was applied to the ventral tegmental area of anesthetized rats by reverse dialysis while extracellular dopamine was sampled with a second dialysis probe in the nucleus accumbens. Orphanin FQ at a probe concentration of 1 mM (but not at 0.1 mM) significantly reduced nucleus accumbens dialysate dopamine levels. The receptor‐inactive analogue, des‐Phe1 ‐orphanin FQ (1 mM), produced a small but significant increase in nucleus accumbens dialysate dopamine levels. Simultaneous measurement of ventral tegmental area dialysate amino acid content revealed significant increases in both GABA and glutamate during infusion of orphanin FQ (1 mM). To determine if increased GABA overflow mediates the action of orphanin FQ on mesolimbic neurons, orphanin FQ (10 nmol) was microinjected directly into the ventral tegmental area in the presence or absence of the GABAA receptor antagonist, bicuculline (1 nmol). Bicuculline transiently blocked the suppressive action of orphanin FQ on accumbens dialysate dopamine levels. These data indicate that orphanin FQ decreases dopamine transmission in the nucleus accumbens by inhibiting dopamine neuronal activity in the ventral tegmental area through a mechanism that may involve an increased overflow of GABA.
Increased AP‐1 DNA Binding Activity in PC12 Cells Treated with Lead
Authors: Chakraborti Tamal , Kim Kyung‐Ah , Goldstein Gary G. , Bressler Joseph P.
Published: March 2003

Abstract: The possibility that the mechanism of lead neurotoxicity may be at the level of transcription was investigated in PC12 cells. In electrophoretic mobility gel shift assays Pb2+ was found to increase activator protein‐1 complex (AP‐1) DNA binding activity in PC12 cells; the increase was time‐ and concentration‐dependent. Exposure to Pb2+ also resulted in an increase in AP‐1‐driven transcription in cerebellar granule cells transfected with a luciferase gene reporter construct. The increase in AP‐1 DNA binding activity by Pb2+ required protein synthesis. The increase was mediated by protein kinase C because depletion of protein kinase C and an inhibitor of protein kinase C prevented the increase in AP‐1 DNA binding activity by Pb2+. Fra‐2 and JunD were found in supershift assays to be the major components of the AP‐1 that was increased by Pb2+. In summary, our studies indicate that Pb2+ increases AP‐1 DNA binding activity in PC12 cells by a pathway that requires protein kinase C and new protein synthesis.
Effect of Chronic Angiotensin‐Converting Enzyme Inhibition on Striatal Dopamine Content in the MPTP‐Treated Mouse
Authors: Jenkins Trisha A. , Wong John Y. F. , Howells David W. , Mendelsohn Frederick A. O. , Chai Siew Yeen
Published: March 2003

Abstract: We have previously shown that chronic treatment with the angiotensin‐converting enzyme inhibitor perindopril increased striatal dopamine levels by 2.5‐fold in normal Sprague—Dawley rats, possibly via modulation of the striatal opioid or tachykinin levels. In the present study, we investigated if this effect of perindopril persists in an animal model of Parkinson’s disease, the 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP)‐treated mouse. C57BL/6 mice were treated with the neurotoxin (30 mg/kg/day intraperitoneally) for 4 days and then left for 3 weeks to allow the degeneration of striatal dopaminergic terminals. At this time, the mice exhibited a 40% decrease in striatal dopamine content and an accompanying 46% increase in dopamine D2 receptor levels compared with control untreated mice. The dopamine content returned to control levels, and the increase in dopamine D2 receptor levels was attenuated in mice treated with perindopril (5 mg/kg/day orally for 7 days) 2 weeks after the last dose of MPTP. When the angiotensin‐converting enzyme inhibitor was administered (5 mg/kg/day for 7 days) immediately after the cessation of the MPTP treatment, there was no reversal of the effect of the neurotoxin in decreasing striatal dopamine content. Our results demonstrate that perindopril is an effective agent in increasing striatal dopamine content in an animal model of Parkinson’s disease.
Effects of Systemic Immunogenic Insults and Circulating Proinflammatory Cytokines on the Transcription of the Inhibitory Factor κBα Within Specific Cellular Populations of the Rat Brain
Authors: Laflamme Nathalie , Rivest Serge
Published: March 2003

Abstract: Expression of the inhibitory factor κBα (IκBα) reflects the activity of nuclear factor κB(NF‐κB) and is a powerful tool to investigate the regulation of the transcription factor within the CNS. IκBα mRNA was evaluated in the rat brain by means of in situ hybridization following different immunogenic stimuli; i.e., intraperitoneal (i.p.) and intravenous (i.v.) lipopolysaccharide (LPS), i.v. recombinant rat interleukin (IL) 1β, IL‐6, or tumor necrosis factor‐α (TNF‐α), and intramuscular (i.m.) turpentine injection, used here as a model of systemic localized inflammatory insult. Systemic LPS, IL‐1β, and TNF‐α caused a rapid and transient transcriptional activation of IκBα along the blood vessels of the entire brain; the signal was very intense 30‐60 min after the i.v. injections and returned to undetectable levels from 2 to 12 h depending on the challenge. Double‐labeling procedure provided the anatomical evidence that IκBα‐expressing cells within the microvasculature were essentially of the endothelial type, as they were immunoreactive to the von Willebrand factor. Scattered small cells were also found across the brain of LPS‐, IL‐1β‐, and TNF‐α‐injected rats at time 1‐3 h, and microglial (OX‐42)‐immunoreactive cells were positive for the transcript. Such expression within parenchymal microglia was nevertheless not observed in the brain following a localized and sterile inflammatory insult. Indeed, i.m. turpentine administration stimulated IκBα transcription quite uniquely within the endothelium of the brain capillaries, an effect that paralleled the swelling of the injection site and lasted up to 24 h after the aggression. In contrast to these immunogenic challenges, i.v. IL‐6 injection failed to activate the gene encoding IκBα in the rat brain. These results indicate that NF‐κB may play a crucial role in specific cellular populations of the CNS to trigger transcription of immune‐related genes and that IκBα resynthesis may act as a dynamic intracellular inhibitory feedback to avoid exaggeration of the response. It is possible that IκBα expression in cells of the blood‐brain barrier is a general mechanism that takes place during systemic inflammation, whereas the participation of NF‐κB‐related molecules within parenchymal cells of the CNS is solicited during more severe conditions such as blood sepsis and endotoxemia.
Astroglia Contain a Specific Transport Mechanism for N‐Acetyl‐l‐Aspartate
Authors: Sager Thomas Nikolaj , Thomsen Christian , Valsborg Jacob Stenmann , Laursen Henning , Hansen Anker Jon
Published: March 2003

Abstract : N‐Acetylaspartate (NAA) is the second most

abundant amino acid in the adult brain. It is located and synthesized in

neurons and probably degraded in the glia compartment, but the transport

mechanisms are unknown. Rat primary neuron and astrocyte cell cultures were

exposed to the L isomer of [3H]NAA and demonstrated

concentration‐dependent uptake of [3H]NAA with a

Km≈80 μM. However,

Vmax was 23 ± 6.4 pmol/mg of protein/min in

astrocytes but only 1.13 ± 0.4 pmol/mg of protein/min in neurons. The

fact that neuron cultures contain 3‐5% astrocytes suggests that the uptake

mechanism is expressed only in glial cells. The astrocyte uptake was

temperature and sodium chloride dependent and specific for l‐NAA.

The affinity for structural analogues was (IC50 in mM) as

follows : l‐NAA (0.12) > N‐acetylaspartyglutamate (0.4)

> N‐acetylglutamate (0.42) > l‐aspartate (>1)

> l‐glutamate (>1) ≥dl‐threo‐β‐hydroxyaspartate >

N‐acetyl‐l‐histidine. The naturally occurring amino acids

showed no inhibitory effect at 1 mM. The glutamate transport blocker

trans‐pyrrolidine‐2,4‐dicarboxylate exhibited an IC50 of

0.57 mM, whereas another specific glutamate transport inhibitor,

dl‐threo‐β‐hydroxyaspartate, had an IC50

of >1 mM. The experiments suggest that NAA transport in brain parenchyma occurs by a novel type of sodium‐dependent carrier that is present only in glial cells.
Modulation of the Mesolimbic Dopamine System by Glutamate
Authors: Kretschmer Beate D.
Published: March 2003

Abstract : Glutamate has been shown to modulate motor behavior,

probably via N‐methyl‐d‐aspartate (NMDA) and

α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid (AMPA) receptors

that are involved in the control of the mesolimbic dopamine (DA) system, that

is, the ventral tegmental area (VTA)‐nucleus accumbens (NAC). In the present

study, we investigated the effects of uncompetitive (MK‐801) and competitive

[dl‐2‐amino‐5‐phosphonopentanoic acid (AP‐5), CGP 40116] NMDA receptor antagonists and NMDA and AMPA on DA release in the mesolimbic system and on motor behavior. Systemic injection and intrategmental infusion of MK‐801 increased DA levels in the VTA, but the systemic administration enhanced DA exclusively in the NAC and increased motor behavior. In contrast, intrategmental infusion of AP‐5, but not the systemic administration of its lipophilic analogue CGP 40116, decreased the DA release in the two regions without affecting motor behavior. NMDA and AMPA infusion into the VTA increased DA levels in both areas. This increase was accompanied by a strong motor behavioral stimulation after NMDA but only a moderate increase after AMPA infusion. The present results indicate that mesolimbic DA neurons are controlled by the glutamatergic system and that the effects of uncompetitive and competitive NMDA receptor antagonists on DA release are mediated by an interaction with different brain areas. These findings may account for the different effects of NMDA receptor ligands on motor behavior.
The Nonfibrillar Amyloid β‐Peptide Induces Apoptotic Neuronal Cell Death
Authors: Pillot Thierry , Drouet Béatrice , Queillé Sophie , Labeur Christine , Vandekerckhove Joël , Rosseneu Maryvonne , Pinçon‐Raymond Martine , Chambaz Jean
Published: March 2003

Abstract : The toxicity of the nonaggregated amyloid β‐peptide (1‐40) [Aβ(1‐40)] on the viability of rat cortical neurons in primary culture was investigated. We demonstrated that low concentrations of Aβ peptide, in a nonfibrillar form, induced a time‐ and dose‐dependent apoptotic cell death, including DNA condensation and fragmentation. We compared the neurotoxicity of the Aβ(1‐40) peptide with those of several Aβ‐peptide domains, comprising the membrane‐destabilizing C‐terminal domain of Aβ peptide (e.g., amino acids 29‐40 and 29‐42). These peptides reporduced the effects of the (1‐40) peptide, whereas mutant nonfusogenic Aβ peptides and the central region of the Aβ peptide (e.g., amino acids 13‐28) had no effect on cell viability. We further demonstrated that the neurotoxicity of the nonaggregated Aβ peptide paralleled a rapid and stable interaction between the Aβ peptide and the plasma membrane of neurons, preceding apoptosis and DNa fragmentation. By contrast, the peptide in a fibrillar form induced a rapid and dramatic neuronal death mainly through a necrotic pathway, under our conditions. Taken together, our results suggest that Aβ induces neuronal cell death by either apoptosis and necrosis and that an interaction between the nonfibrillar C‐terminal domain of the Aβ peptide and the plasma membrane of cortical neurons might represent an early event in a cascade leading to neurodegeneration.
c‐Jun Contributes to Amyloid β‐Induced Neuronal Apoptosis but Is Not Necessary for Amyloid β‐Induced c‐jun Induction
Authors: Kihiko Muthoni E , Tucker H. Michael , Rydel Russell E , Estus Steven
Published: March 2003

Abstract : The role of gene expression in neuronal apoptosis may be

cell‐ and apoptotic stimulus‐specific. Previously, we and others showed that

amyloid β (Aβ)‐induced neuronal apoptosis is accompanied by

c‐jun induction. Moreover, c‐Jun contributes to neuronal death in

several apoptosis paradigms involving survival factor withdrawal. To evaluate

the role of c‐Jun in Aβ toxicity, we compared Aβ‐induced apoptosis

in neurons from murine fetal littermates that were deficient or wild‐type with

respect to c‐Jun. We report that neurons deficient for c‐jun are

relatively resistant to Aβ toxicity, suggesting that c‐Jun contributes to

apoptosis in this model. When changes in gene expression were quantified in

neurons treated in parallel, we found that Aβ treatment surprisingly led

to an apparent activation of the c‐jun promoter in both

c‐jun‐deficient and wild‐type neurons, suggesting that c‐Jun is not

necessary for activation of the c‐jun promoter. Indeed, several genes

induced by Aβ in wild‐type neurons were also induced in

c‐jun‐deficient neurons, including c‐fos, fosB,

ngfi‐B, and iκB. In summary, these results indicate

that c‐Jun contributes to Aβ‐induced neuronal death but that c‐Jun is not

necessary for c‐jun induction.
Metabolic Consequences of the CytochromecOxidase Deficiency in Brain of Copper‐Deficient MovbrMice
Authors: Kunz Wolfram S. , Kuznetsov Andrey V. , Clark Joseph F. , Tracey Irene , Elger Christian E.
Published: March 2003

Abstract:Biochemical micromethods were used for the investigation of changes in mitochondrial oxidative phosphorylation associated with cytochromecoxidase deficiency in brain cortex from Movbr(mottled viable brindled) mice, an animal model of Menkes’ copper deficiency syndrome. Enzymatic analysis of cortex homogenates from Movbrmice showed an approximately twofold decrease in cytochromecoxidase and a 1.4‐fold decrease in NADH:cytochromecreductase activities as compared with controls. Assessment of mitochondrial respiratory function was performed using digitonin‐treated homogenates of the cortex, which exhibited the main characteristics of isolated brain mitochondria. Despite the substantial changes in respiratory chain enzyme activities, no significant differences were found in maximal pyruvate or succinate oxidation rates of brain cortex homogenates from Movbrand control mice. Inhibitor titrations were used to determine flux control coefficients of NADH:CoQ oxidoreductase and cytochromecoxidase on the rate of mitochondrial respiration. Application of amobarbital to titrate the activity of NADH:CoQ oxidoreductase showed very similar flux control coefficients for control and mutant animals. Alternately, titration of respiration with azide revealed for Movbrmice significantly sharper inhibition curves than for controls, indicating a more than twofold elevated flux control coefficient of cytochromecoxidase. Owing to the reserve capacity of respiratory chain enzymes, the reported changes in activities do not seem to affect whole‐brain high‐energy phosphates, as observed in a previous study using31P NMR.
Neural Regulation of α‐Dystroglycan Biosynthesis and Glycosylation in Skeletal Muscle
Authors: Leschziner Andres , Moukhles Hakima , Lindenbaum Michael , Gee Stephen H. , Butterworth Joanne , Campbell Kevin P. , Carbonetto Salvatore
Published: March 2003

Abstract:α‐Dystroglycan (α‐DG) is part of a complex of cell surface proteins linked to dystrophin or utrophin, which is distributed over the myofiber surface and is concentrated at neuromuscular junctions. In laminin overlays of muscle extracts from developing chick hindlimb muscle, α‐DG first appears at embryonic day (E) 10 with an apparent molecular mass of 120 kDa. By E15 it is replaced by smaller (∼100 kDa) and larger (∼150 kDa) isoforms. The larger form increases in amount and in molecular mass (>200 kDa) as the muscle is innervated and the postsynaptic membrane differentiates (E10‐E20), and then decreases dramatically in amount after hatching. In myoblasts differentiating in culture the molecular mass of α‐DG is not significantly increased by their replication, fusion, or differentiation into myotubes. Monoclonal antibody IIH6, which recognizes a carbohydrate epitope on α‐DG, preferentially binds to the larger forms, suggesting that the core protein is differentially glycosylated beginning at E16. Consistent with prior observations implicating the IIH6 epitope in laminin binding, the smaller forms of α‐DG bind more weakly to laminin affinity columns than the larger ones. In blots of adult rat skeletal muscle probed with radiolabeled laminin or monoclonal antibody IIH6, α‐DG appears as a >200‐kDa band that decreases in molecular mass but increases in intensity following denervation. Northern blots reveal a single mRNA transcript, indicating that the reduction in molecular mass of α‐DG after denervation is not obviously a result of alternative splicing but is likely due to posttranslational modification of newly synthesized molecules. The regulation of α‐DG by the nerve and its increased affinity for laminin suggest that glycosylation of this protein may be important in myofiber‐basement membrane interactions during development and after denervation.