bluuebunny/crossref_metadata_2025 huggingface dataset:
Temporary versus Permanent Youth Brain Drain: Economic Implications
Authors: Baláz Vladimír , Williams Allan M. , Kollár Daniel
Published: November 2004

Existing high levels of temporary migration between Central and Eastern Europe and the European Union (EU) have highlighted a number of concerns relating to the eastern enlargement of the Union. While much of the debate has focused on the destinations, we use Slovakia as a case study to explore economic implications for the countries of origin of highly skilled migrants. First, the paper examines estimates of the scale of “youth brain migration”, comparing survey‐based and expert‐opinion estimates with our own estimate based on reconciling labour market and educational data. This identifies a substantial loss of graduate workers from the labour force through migration, accounting for a potentially significant proportion of Gross Domestic Product (GDP) growth. Second, we consider whether such migration will constitute “brain drain/overflow” or “brain circulation”: in other words will it be temporary or permanent? In some ways, however, this is a false dichotomy, for there are strong links between initial temporary migration and intended permanent migration, explored here through a survey of the motivations and social networks of returned migrants. Third, we address the ability of national states to intervene to mediate such losses. We generally concur with other commentators on the need for a multi‐scalar and multi‐functional approach, focusing especially on economic development. However, we are pessimistic about the likely speed of economic convergence and, moreover, argue that initial temporary migration (with implications for permanent migration) will continue to be driven by non‐economic goals.
Differences in sounds made by courting males of three closely related Lake Malawi cichlid species
Authors: Amorim M. C. P. , Knight M. E. , Stratoudakis Y. , Turner G. F.
Published: November 2004

Courtship sounds made by three sympatric cichlid species, Pseudotropheus zebra, P. callainos and an undescribed species known as P. ‘zebra gold’ were recorded and compared to investigate the potential role of acoustic signals in mate choice. Sounds were emitted during ‘quiver’ and ‘circle’ components of the male courtship display and consisted of rapidly repeated pulse units. Some sound variables differed significantly among species with P. callainos generally being separated from the other two species. This species produced sounds with higher peak frequency (for a given length) and lower number of pulses than P. ‘zebra gold’ and higher pulse durations than P. zebra. In addition, standard length was inversely related to peak frequency in both P. ‘zebra gold’ and P. callainos(this relation was not tested in P. zebra due to the small sample size). These differences might indicate different regimes of intraspecific sexual selection among the three species.
A cross‐river antenna array for the detection of miniature passive integrated transponder tags in deep, fast flowing rivers
Authors: Ibbotson A. T. , Beaumont W. R. C. , Collinson D. , Wilkinson A. , Pinder A. C.
Published: November 2004

A novel cross river, self cleansing system for the remote monitoring of downstream and upstream migration of PIT tagged fishes past a fixed point in deep, fast flowing rivers is described.
Autoantibodies to REG, a beta‐cell regeneration factor, in diabetic patients
Authors: Shervani N. J. , Takasawa S. , Uchigata Y. , Akiyama T. , Nakagawa K. , Noguchi N. , Takada H. , Takahashi I. , Yamauchi A. , Ikeda T. , Iwamoto Y. , Nata K. , Okamoto H.
Published: November 2004

Background  Regenerating gene (Reg) product, Reg, acts as an autocrine/paracrine growth factor for beta‐cell regeneration. The presence of autoimmunity against REG may affect the operative of the regenerative mechanisms in beta cells of Type 1 and Type 2 diabetes patients. We screened sera from Type 1 and Type 2 diabetes subjects for anti‐REG autoantibodies, searched for correlations in the general characteristics of the subjects with the presence of anti‐REG autoimmunity, and tested the attenuation of REG‐induced beta‐cell proliferation by the autoanitibodies.

Material and methods  We examined the occurrence of anti‐REG autoantibodies in patients’ sera (265 Type 1, 368 Type 2 diabetes patients, and 75 unrelated control subjects) by Western blot analysis, and evaluated inhibitory effects of the sera on REG‐stimulated beta‐cell proliferation by a 5′‐Bromo‐2′‐deoxyuridine (BrdU) incorporation assay in vitro.

Results  Anti‐REG autoantibodies were found in 24·9% of Type 1, 14·9% of Type 2 and 2·7% of control subjects (P = 0·0004). There were significant differences between the autoantibody positive and negative groups in the duration of disease in the Type 1 subjects (P = 0·0035), and the age of onset in the Type 2 subjects (P = 0·0274). The patient sera containing anti‐REG autoantibodies significantly attenuated the BrdU incorporation by REG (35·6 ± 4·06% of the control), whereas the nondiabetic sera without anti‐REG autoantibodies scarcely reduced the incorporation (88·8 ± 5·10%).

Conclusion  Anti‐REG autoantibodies, which retard beta‐cell proliferation in vitro, are found in some diabetic patients. Thus, autoimmunity to REG may be associated with the development/acceleration of diabetes in at least some patients.
Problem‐solving competency of nursing graduates
Authors: Uys Leana R. , Van Rhyn Lily L. , Gwele Nomthandaso S. , McInerney Patricia , Tanga Tobeka
Published: November 2004

Aim.  This paper reports a study describing and evaluating the outcomes of problem‐based learning (PBL) programmes in nursing schools in South Africa in terms of the competence of graduates to solve problem in actual clinical settings, and comparing this competence with that of graduates from non‐PBL programmes.

Background.  The nursing literature tends to equate problem‐solving with patient‐centred problems or the nursing process. However, it is also a skill used in managing the work role, working in a team and managing a health care unit. Problem‐solving refers to the process of selectively attending to information in a patient care setting. The investigation of problem‐solving in nursing is complicated by the complex relationships between different cognitive processes.

Methods.  A qualitative evaluation study, descriptive and comparative in nature, was carried out. In‐depth interviews were held with graduates and their supervisors, asking them to identify problem‐solving incidents in which they had been involved. Template analysis style and Benner's interpretive approach were used to analyse the data.

Findings.  The majority of the incidents described by the graduates (84%) were graded at the advanced beginner level or above. The majority of incidents at the novice level came from the non‐PBL group. ‘Using people skills’ and ‘being assertive’ were the two problem‐solving strategies most often used. The PBL group fared better than the non‐problem‐based group in the level of their problem‐solving ability.

Conclusion.  The findings of this study suggest that further research is warranted into the problem‐solving abilities of PBL graduates, their personal development over time and at different stages of practice. In addition, it would be interesting to follow the development of their problem‐solving abilities over time.
Homozygous familial hypercholesterolaemia presenting with cutaneous xanthomas: Response to liver transplantation
Authors: Moyle Mignon , Tate Bruce
Published: November 2004

SUMMARY A 19‐month‐old girl with cutaneous xanthomas was diagnosed with homozygous familial hypercholesterolaemia, treated with atorvastatin, plasma exchange and finally at the age of 3.5 years, with liver transplantation. Her serum cholesterol levels fell to normal and the xanthomas regressed following liver transplantation. She remains well 17 months post transplant.
Survival and recruitment of seedlings and suckers of trees and shrubs of the Australian arid zone following habitat management and the outbreak of Rabbit Calicivirus Disease (RCD)
Authors: Denham Andrew J. , Auld Tony D.
Published: November 2004

Abstract Recruitment in many shrub and tree species in arid Australia is limited by domestic and feral animal grazing. The outbreak of Rabbit Calicivirus Disease (RCD or RHD) in late 1995 at Kinchega National Park (NP) in arid western NSW, Australia, coincided with intensified warren ripping and other rabbit (Oryctolagus cuniculus) control efforts. We monitored changes in rabbit numbers in response to these factors using spotlight counts and dung‐pellet counts. Rabbit populations declined initially, and were low for the remainder of the study. To assess the impact of rabbit control on vegetation, we examined whether recruitment of seedlings or vegetative suckers was occurring at Kinchega NP, following the arrival of RCD; how long such recruits were likely to survive under current grazing pressures; and whether the magnitude of current seedling and vegetative sucker recruitment and survival is greater than available data prior to RCD and extensive warren control. We followed the survival of individual seedlings and newly emerged suckers of six shrub or tree species, most of which are considered to be at risk of local decline. Three levels of caging were used to exclude all mammalian grazers; all mammalian grazers except rabbits; and no mammalian grazers. Pooled cohorts of seedlings and suckers were analysed using failure‐time analyses. During the course of the study, suckering was observed in four species (Acacia carneorum,Alectryon oleifolius,Casuarina pauperandSantalum acuminatum), with seedlings observed in the other two species (Dodonaea viscosaandAcacia ligulata). Survival of suckers of some species was slightly greater than pre‐RCD estimates, but in general, a pattern of little or nil recruitment is likely in suckers exposed to rabbits or to all grazing mammals. Seedling survival was particularly low regardless of the level of exclusion, largely due to desiccation. Reduction of grazing impacts may only allow recruitment into populations of species reliant on seedlings under more favourable climatic circumstances than experienced in this study, while the probability of successful recruitment into populations of suckering species in western NSW continues to be low even at very low rabbit densities.
Interaction of multiple disturbances: importance of disturbance interval in the effects of fire on rehabilitating mined areas
Authors: Ross Karen A. , Taylor Jennifer E. , Fox Marilyn D. , Fox Barry J.
Published: November 2004

Abstract  Multiple disturbance regimes are increasingly common as novel anthropogenic disturbances are added to existing natural disturbances. However, it is generally unknown whether simultaneous or sequential effects of different forms of disturbance are predictable from the independent effects of each disturbance. This study examines the short‐term effects of sequential disturbance by mineral sand‐mining followed by fire in a forest community in south‐eastern Australia. Four combinations of disturbance were sampled: unburned mined, burned mined, unburned forest (unmined) and burned forest (unmined, with between‐fire interval matching the disturbance interval between mining and fire of the burned mined treatment). All combinations were sampled approximately 12 months following fire on the burned sites. The impact of fire after mining depended on disturbance interval. Sites burned 0.5–2.4 years since mining had fewer native vascular plant species than unburned mined sites of the same mined age, whereas sites with 10–16 years or 20–26 years between mining and fire had greater native species richness than unburned mined sites of the same age. Burning 20–26 years after mining brought native species richness within the range of burned forest. For both unmined and mined sites native seedling densities increased with burning, and with longer disturbance intervals. Weed species richness and weed seedling densities were greater on mined sites than in forest, and burning mined sites elevated weed seedling densities further, particularly for short intervals. Both disturbance interval and fire intensity are likely to have contributed to these results, as intensity on mined areas increased with interval, and at 20–26 years post‐mining was equivalent to unmined forest. These results suggest that fire could be used to promote rehabilitation of these mined areas after at least 10 years, but should be excluded from earlier stages of post‐mining regeneration. However, other sources of spatial and temporal variability should be considered in addition to interval and intensity, as variation among mined areas was correlated with post‐fire weather conditions and available weed sources. Finally, the combined effects of mining and fire could not be predicted from knowledge of the disturbances operating separately, indicating that effects of multiple disturbance may be synergistic rather than additive.
Cannabinoid CB2 receptor activation inhibits mechanically evoked responses of wide dynamic range dorsal horn neurons in naïve rats and in rat models of inflammatory and neuropathic pain
Authors: Elmes Steven J. R. , Jhaveri Maulik D. , Smart Darren , Kendall David A. , Chapman Victoria
Published: November 2004

Peripheral cannabinoid 2 receptors (CB2 receptors) modulate immune responses and attenuate nociceptive behaviour in models of acute and persistent pain. The aim of the present study was to investigate whether peripheral CB2 receptors modulate spinal processing of innocuous and noxious responses and to determine whether there are altered roles of CB2 receptors in models of persistent pain. Effects of local administration of the CB2 receptor agonist JWH‐133 (5 and 15 µg/50 µL) on mechanically evoked responses of spinal wide dynamic range (WDR) neurons in noninflamed rats, rats with carrageenan‐induced hindpaw inflammation, sham operated rats and spinal nerve‐ligated (SNL) rats were determined in anaesthetized rats in vivo. Mechanical stimulation (von Frey filaments, 6–80 g) of the peripheral receptive field evoked firing of WDR neurons. Mechanically evoked responses of WDR neurons were similar in noninflamed, carrageenan‐inflamed, sham‐operated and SNL rats. Intraplantar injection of JWH‐133 (15 µg), but not vehicle, significantly (P < 0.05) inhibited innocuous and noxious mechanically evoked responses of WDR neurons in all four groups of rats. In many cases the selective CB2 receptor antagonist, SR144528 (10 µg/50 µL), attenuated the inhibitory effects of JWH‐133 (15 µg) on mechanically evoked WDR neuronal responses. The CB1 receptor antagonist, SR141716A, did not attenuate the inhibitory effects of JWH‐133 on these responses. Intraplantar preadministration of JWH‐133 also inhibited (P < 0.05) carrageenan‐induced expansion of peripheral receptive fields of WDR dorsal horn neurons. This study demonstrates that activation of peripheral CB2 receptors attenuates both innocuous‐ and noxious‐evoked responses of WDR neurons in models of acute, inflammatory and neuropathic pain.
Vigilance states in a parkinsonian model, the MPTP mouse
Authors: Monaca Christelle , Laloux Charlotte , Jacquesson Jean‐Marie , Gelé Patrick , Maréchal Xavier , Bordet Régis , Destée Alain , Derambure Philippe
Published: November 2004

Sleep disturbances and vigilance disorders are frequently observed in Parkinson's disease. Despite the fact that the 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP) mouse is one of the best‐known animal models of Parkinson's disease, sleep analysis has never previously been performed in this system. In the present study, we explored sleep–wakefulness cycles in MPTP‐treated mice and compared the results to data from untreated mice. MPTP (25 mg/kg) was injected daily for 5 days. After recovery, polysomnography was recorded over 48 h. Dopaminergic lesions of the substantia nigra and striata were evaluated using immunohistochemical markers. Immunohistochemical analysis showed a loss of dopaminergic neurons in MPTP mice. Compared with controls, MPTP‐treated mice presented changes in sleep architecture throughout the nycthemeral period, with longer wakefulness and paradoxical sleep episodes and an increase in the amount of paradoxical sleep. We observed changes in sleep architecture in MPTP‐treated mice, compared with saline‐treated mice. MPTP mice show more consolidated vigilance states with higher amount of paradoxical sleep than controls. Although the MPTP‐treated mouse is not a good model of sleep disturbances in PD, our results suggest that it could be a good pharmacological model for studying the effects of dopaminergic treatments on animal sleep–wakefulness cycles.
Regenerating corticospinal fibers in the Marmoset (Callitrix jacchus) after spinal cord lesion and treatment with the anti‐Nogo‐A antibody IN‐1
Authors: Fouad K. , Klusman I. , Schwab M. E.
Published: November 2004

Neutralizing the myelin‐associated growth inhibitor Nogo‐A in adult spinal cord‐injured rats can promote regeneration of injured and compensatory sprouting of uninjured axons. Nogo‐A is present in humans, making its neutralization a possible novel treatment option for paraplegic patients. In this study we examined the effects of an extensively used anti‐Nogo‐A antibody (mAb IN‐1) on the regenerative capabilities of lesioned corticospinal tract (CST) axons in a primate, the Marmoset monkey. Unilateral thoracic lesions of the CST were performed in six adult Marmosets, followed by the application of mAb IN‐1 into the cerebrospinal fluid circulation by a graft of hybridoma cells. A unilateral injection of biotin dextran amine into the motor cortex was performed to analyse sprouting and regeneration of the lesioned axons. In the control antibody‐treated animal CST fibers stopped rostral to the lesion site and often showed retraction bulbs. In contrast, in four out of five mAb IN‐1‐treated animals fine labeled neurites had grown into, through and around the lesion site. Thus, this study provides first anatomical evidence that in primates, the neutralization of the myelin‐associated inhibitor Nogo‐A results in increased regenerative sprouting and growth of lesioned spinal cord axons.
Characteristics of and interventions for fever in Japan
Authors: Ikematsu Y.
Published: November 2004

Purpose:  As part of a larger multinational validation study of the International Classification for Nursing Practice (ICNP®) alpha version, a survey was conducted in Japan to determine characteristics of ‘fever’ and interventions to treat febrile patients.

Sample:  Three hundred and fifty‐six acute and critical care Japanese nurses participated in this study.

Method:  The major and minor characteristics of ‘fever’ perceived by Japanese nurses and interventions used by the nurses in managing febrile patients were identified using the Diagnostic Content Validity (DCV) model.

Results:  Two characteristics, ‘increased body temperature’ and ‘chills’ were selected as major characteristics from the standardized list of the ICNP® alpha version validation study. Nine characteristics among the standardized list of characteristics were rated as minor characteristics, and six of the ICNP® characteristics were rejected. ‘Shivering’ and ‘infectious lab data’ were added with a level of representativeness similar to a major characteristic by nine of the nurses. A variety of interventions to treat fever were reported. The most frequently reported intervention was cooling, followed by warming and medication. Nine dimensions were derived from all reported interventions.

Discussion:  As well as perceived characteristics of fever, these interventions may have aspects unique to Japanese nursing practice and to the acute and critical care settings. These results can be compared to those of other populations in future studies.
Tackling drug and alcohol misuse in Brazil: priorities and challenges for nurses
Authors: Rassool G. H. , Villar‐Luis M.
Published: November 2004

Aims:  To provide an overview of the extent of drug and alcohol misuse in Brazil and the policies and approaches in tackling substance misuse. An examination of the challenges facing the nursing profession in working with substance misusers is presented.

Background:  Alcohol, cocaine, and cannabis are the most commonly misused psychoactive substances in Brazil. One of the biggest public health problems is the interface between the misuse of psychoactive substances and HIV prevalence and other sexually transmitted diseases. Findings from a recent study suggest that undergraduate nurses in Brazil are not adequately prepared in the care and management of substance misuse problems. The nursing profession in Brazil faces numerous challenges in the development of professional competence of nurses in this field.

Conclusion:  A strategy proposed is the creation of regional centres in Brazil to study the integration of substance use and misuse in the nursing undergraduate curriculum and the giving of specific support in teaching and research to nurse teachers. Nurses have a key role to play in the early recognition, assessment, prevention, and treatment of substance misuse.
Nursing diagnosis with the ICNP® in the teaching context
Authors: Zarzycka D. , Górajek‐Jóźwik J.
Published: November 2004

Background:  The premise for the research study was the authors’ conviction that the use of nursing diagnostic taxonomies allows the nurse to formulate a thorough and valid diagnosis. Aim: To verify the International Classification for Nursing Practice (ICNP®) in the context of a Polish academic nursing programme.

Research questions:  Do nursing diagnoses made traditionally and those made with the ICNP® reflect the patient’s/client's condition? Is the range and type of the two kinds of diagnoses similar or different? Is the level of detail in both types of diagnoses compatible?

Methods:  Quasi‐experiment in which the experimental group diagnosed patients by means of the ICNP® and the control group formulated nursing diagnoses by means of an intellectual decision‐making process.

Study groups:  44 students in a MNurs. Programme, Faculty of Nursing and Health Sciences, Medical University in Lublin, Poland.

Conclusions:  The range and type of nursing diagnoses do not depend on the method used in their formulation. The ICNP® diagnoses are compatible with the traditionally formulated ones. The unbalanced size of the experimental and the study groups negatively influenced the validity of conclusions.
Characterization of a Schwann cell enhancer in the myelin basic protein gene
Authors: Taveggia Carla , Pizzagalli Antonella , Fagiani Ernesta , Messing Albee , Feltri M. Laura , Wrabetz Lawrence
Published: November 2004

Oligodendrocytes and Schwann cells use diverse regulatory elements to transcribe myelin basic protein (Mbp). For example, an enhancer 9.0 kb upstream ofMbp(MbpSCE1) activated either the proximalMbporhsp68promoters only in Schwann cells in transgenic mice. Here, we analyzeMbpSCE1in vitroandin vivoand show thatMbpSCE1 also activates another myelin gene,Mpz, specifically in Schwann cells in transgenic mice. Surprisingly, althoughMbpSCE1 behaves as an enhancer in Schwann cells, we show here for the first time that it also activates transcription robustly in cultured oligodendrocytes, but only from its original genomic position. Diverse nuclear proteins binding at distinct combinations of DNA elements in the two cell types may account for cell‐specificMbpSCE1 function. A further surprise is thatMbpSCE1 activation does not depend on consensus binding sites for the myelin‐associated PPARβ or Krox 20 transcription factors. Finally, chromatin context augments activation ofMbpSCE1. Therefore,MbpSCE1 is active in both Schwann cells and oligodendrocytes, but by diverse mechanisms.
Involvement of gangliosides in proliferation of immortalized neural progenitor cells
Authors: Yanagisawa Makoto , Liour Sean S. , Yu Robert K.
Published: November 2004

The CNS consists of neuronal and glial cells generated from common neural progenitor cells during development. Cellular events for neural progenitor cells, such as proliferation and differentiation, are regulated by multiple intrinsic and extrinsic cell signals. Although much is known on the importance of the proteinous factors in regulating the fate of neural progenitor cells, the involvement of other molecules such as gangliosides, sialic acid‐containing glycosphingolipids, remains to be clarified. To elucidate the biological functions of gangliosides in neural progenitor cells, we transfected an immortalized neural progenitor cell line, C17.2, which does not express GD3 ganglioside, with a fusion protein of GD3‐synthase (ST‐II) and enhanced green fluorescent protein (ST‐II‐EGFP). Analysis of the ST‐II transfectants revealed the ectopic expression of b‐ and c‐series gangliosides. In the ST‐II transfectants, proliferation induced by epidermal growth factor (EGF) was severely retarded. EGF‐induced proliferation of C17.2 cells was dependent on the Ras‐mitogen‐activated protein kinase (Ras‐MAPK) pathway, and the EGF‐induced activation of this pathway was significantly repressed in the transfectants. Thus, ST‐II overexpression retarded proliferation of C17.2 cells via repression of the Ras‐MAPK pathway. The result supports the concept that gangliosides may play an important role in regulating the proliferation of neural progenitor cells.
Involvement of OCTN2 and B0,+in the transport of carnitine through anin vitromodel of the blood–brain barrier
Authors: Berezowski Vincent , Miecz Dorota , Marszałek Mariusz , Bröer Angelika , Bröer Stefan , Cecchelli Roméo , A. Nałęcz Katarzyna
Published: November 2004

Carnitine is known to accumulate in brain, therefore transport of carnitine through the blood–brain barrier was studied in anin vitrosystem using bovine brain capillary endothelial cells (BBCEC) grown on filter inserts in a co‐culture system with glial cells. Long‐term exposure of BBCEC to carnitine resulted in a high accumulation of long‐chain acyl carnitines, which decreased dramatically upon removal of carnitine. Kinetic analysis of carnitine accumulation indicated a possibility of functioning of more than one transporter. BBCEC were incubated in the presence of substrates and inhibitors of known carnitine transporters added from either apical or basolateral side. Inhibition by replacement of sodium and expression of OCTN2 (RT‐PCR) were in agreement with earlier reports on the functioning of OCTN2 in apical membrane. For the first time, functioning of OCTN2 was demonstrated in the basolateral membrane, as well as functioning in both membranes of a low affinity carnitine transporter B0,+. Expression of B0,+in BBCEC was confirmed by RT‐PCR. These results suggest that OCTN2 and B0,+could be involved in carnitine transport in both the apical and basolateral membrane.
Two different Ca2+‐dependent inhibitory mechanisms of spontaneous firing by glutamate in dopamine neurons
Authors: Kim Shin Hye , Choi Yu Mi , Chung Sungkwon , Uhm Dae Yong , Park Myoung Kyu
Published: November 2004

The excitatory neurotransmitter, glutamate, generates a characteristic burst‐pause type of firing in midbrain dopamine neurons in association with the reward behavior, but the cellular mechanism by which glutamate generates these bursts is unknown. Here, we show that the bursts in spontaneously firing dopamine neurons can be generated by the combinative actions of the brief stimulatory and the subsequent Ca2+‐dependent inhibitory signals in response to glutamate stimulation. The two Ca2+‐dependent firing‐extinction signals are activated by different glutamate receptors. Although the activation of metabotropic glutamate receptors rapidly stopped the enhanced firing through the Ca2+ release from intracellular stores, the activation of NMDA and AMPA/kainate receptors abolished the firing immediately after termination of the stimulation due to the Ca2+ accumulation in the cell. These two Ca2+‐dependent inhibitory mechanisms appear to participate in the generation of characteristic bursts in dopamine neurons by controlling the maximum firing number of single bursts and the duration of post‐firing pauses.
First direct demonstration of extensive GABA synthesis in mouse cerebellar neuronal cultures
Authors: Sonnewald Ursula , Olstad Elisabeth , Qu Hong , Babot Zoila , Cristòfol Rosa , Suñol Cristina , Schousboe Arne , Waagepetersen Helle
Published: November 2004

Culturing mouse cerebellar neurones (predominantly glutamatergic) in the presence of [1−13C]glucose for 7 days resulted in a surprisingly extensive labelling of the inhibitory neurotransmitter GABA, the average content and labelling of which were 20 ± 4 nmol/mg protein and 20 ± 4%, respectively. Cultures of neocortical neurones (predominantly GABAergic) had under similar conditions a GABA content and labelling of 32 ± 2 nmol/mg protein and 21 ± 2%. The cerebellar cultures contained only 6% glutamate decarboxylase (GAD)‐positive neurones when immunolabelled using a GAD67 antibody, while a dense network of neurones in the neocortical cultures stained positively for GAD67. Exposure of the cerebellar cultures to 50 µm kainic acid (KA) which is known to eliminate vesicular release of GABA, only marginally affected GABA labelling and cellular content. Likewise this treatment had no effect on the number of GAD67‐positive neurones but a massive punctate immunostaining observed in control cultures was essentially eliminated. Increasing the KA concentration to 0.5 mm in the culture medium for 7 days led to a reduction of GABA labelling and content compared to cerebellar cultures not exposed to KA. Although it is likely that this large capacity for GABA synthesis resides in the relatively few GAD‐positive neurones, it seems unlikely that they could account for the large average GABA content in the cultures. Therefore it must be concluded that the newly synthesized GABA is redistributed among the majority of the cells in these cultures, i.e. the glutamatergic neurones.
Calmodulin reverses rundown of L-type Ca2+ channels in guinea pig ventricular myocytes
Authors: Xu Jian-Jun , Hao Li-Ying , Kameyama Asako , Kameyama Masaki
Published: November 2004

Calmodulin (CaM) is implicated in regulation of Ca2+ channels as a Ca2+ sensor. The effect of CaM on rundown of L-type Ca2+ channels in inside-out patch form was investigated in guinea pig ventricular myocytes. Ca2+ channel activity disappeared within 1–3 min and did not reappear when the patch was excised and exposed to an artificial intracellular solution. However, application of CaM (0.03, 0.3, 3 μM) + 3 mM ATP to the intracellular solution within 1 min after patch excision resulted in dose-dependent activation of channel activity. Channel activity averaged 11.2%, 94.7%, and 292.9%, respectively, of that in cell-attached mode. Channel activity in inside-out patch mode was induced by CaM + ATP at nanomolar Ca2+ concentrations ([Ca2+]); however, increase to micromolar [Ca2+] rapidly inactivated the channel activity induced, revealing that the effect of CaM on the channel was Ca2+ dependent. At the 2nd, 4th, 6th, 8th, and 10th minutes after patch excision, CaM (0.75 μM) + ATP induced Ca2+ channel activity to 150%, 100%, 96.9%, 29.3%, and 16.6%, respectively, revealing a time-dependent action of CaM on the channel. CaM added with adenosine 5′-(β,γ-imido)triphosphate (AMP-PNP) also induced channel activity, although with much lower potency and shorter duration. Protein kinase inhibitors KN-62, CaM-dependent protein kinase (CaMK)II 281-309, autocamtide-related CaMKII inhibitor peptide, and K252a (each 1–10 μM) did not block the effect of CaM, indicating that the effect of CaM on the Ca2+ channel was phosphorylation independent. Neither CaM nor ATP alone induced Ca2+ channel activity, showing a cooperative effect of CaM and ATP on the Ca2+ channel. These results suggest that CaM is a crucial regulatory factor of Ca2+ channel basal activity.
Cellular mechanisms involved in CO2 and acid signaling in chemosensitive neurons
Authors: Putnam Robert W. , Filosa Jessica A. , Ritucci Nicola A.
Published: November 2004

An increase in CO2/H+ is a major stimulus for increased ventilation and is sensed by specialized brain stem neurons called central chemosensitive neurons. These neurons appear to be spread among numerous brain stem regions, and neurons from different regions have different levels of chemosensitivity. Early studies implicated changes of pH as playing a role in chemosensitive signaling, most likely by inhibiting a K+ channel, depolarizing chemosensitive neurons, and thereby increasing their firing rate. Considerable progress has been made over the past decade in understanding the cellular mechanisms of chemosensitive signaling using reduced preparations. Recent evidence has pointed to an important role of changes of intracellular pH in the response of central chemosensitive neurons to increased CO2/H+ levels. The signaling mechanisms for chemosensitivity may also involve changes of extracellular pH, intracellular Ca2+, gap junctions, oxidative stress, glial cells, bicarbonate, CO2, and neurotransmitters. The normal target for these signals is generally believed to be a K+ channel, although it is likely that many K+ channels as well as Ca2+ channels are involved as targets of chemosensitive signals. The results of studies of cellular signaling in central chemosensitive neurons are compared with results in other CO2- and/or H+-sensitive cells, including peripheral chemoreceptors (carotid body glomus cells), invertebrate central chemoreceptors, avian intrapulmonary chemoreceptors, acid-sensitive taste receptor cells on the tongue, and pain-sensitive nociceptors. A multiple factors model is proposed for central chemosensitive neurons in which multiple signals that affect multiple ion channel targets result in the final neuronal response to changes in CO2/H+.
Interaction of a selective serotonin reuptake inhibitor with insulin in the control of hepatic glucose uptake in conscious dogs
Authors: Moore Mary Courtney , DiCostanzo Catherine A. , Dardevet Dominique , Lautz Margaret , Farmer Ben , Cherrington Alan D.
Published: November 2004

Whether hyperinsulinemia is required for stimulation of net hepatic glucose uptake (NHGU) by a selective serotonin reuptake inhibitor (SSRI) was examined in four groups of conscious 42-h-fasted dogs, using arteriovenous difference and tracer ([3-3H]glucose) techniques. Experiments consisted of equilibration (−120 to −30 min), basal (−30 to 0 min), and experimental periods (Exp; 0–240 min). During Exp, somatostatin, intraportal insulin [at basal (Ins groups) or 4-fold basal rates (INS groups)], basal intraportal glucagon, and peripheral glucose (to double hepatic glucose load) were infused. In the Fluv-Ins ( n = 7) and Fluv-INS groups ( n = 6), saline was infused intraportally from 0 to 90 min ( P1), and fluvoxamine was infused intraportally at 2 μg·kg−1·min−1from 90 to 240 min ( P2). Sal-Ins ( n = 9) and Sal-INS ( n = 8) received intraportal saline in P1 and P2. NHGU during P2 was 8.4 ± 1.4 and 6.9 ± 2.3 μmol·kg−1·min−1in Sal-Ins and Fluv-Ins, respectively (not significant), and 13.3 ± 2.2 and 20.9 ± 3.1 μmol·kg−1·min−1( P < 0.05) in Sal-INS and Fluv-INS. Unidirectional (tracer-determined) hepatic glucose uptake was twofold greater ( P < 0.05) in Fluv-INS than Sal-INS. Net hepatic carbon retention during P2 was significantly greater in Fluv-INS than Sal-INS (18.5 ± 2.7 vs. 12.2 ± 1.9 μmol·kg−1·min−1). Nonhepatic glucose uptake was reduced in Fluv-INS vs. Sal-INS (20.0 ± 1.3 vs. 38.4 ± 5.4 μmol·kg−1·min−1, P < 0.05). Intraportal fluvoxamine enhanced NHGU and net hepatic carbon retention in the presence of hyperinsulinemia but not euinsulinemia, suggesting that hepatocyte-targeted SSRIs may reduce postprandial hyperglycemia.
Immunolocalization of NHE8 in rat kidney
Authors: Goyal Sunita , Mentone SueAnn , Aronson Peter S.
Published: November 2004

In situ hybridization studies demonstrated that Na+/H+exchanger NHE8 is expressed in kidney proximal tubules. Although membrane fractionation studies suggested apical brush-border localization, precise membrane localization could not be definitively established. The goal of the present study was to develop isoform-specific NHE8 antibodies as a tool to directly establish the localization of NHE8 protein in the kidney by immunocytochemistry. Toward this goal, two sets of antibodies that label different NHE8 epitopes were developed. Monoclonal antibody 7A11 and polyclonal antibody Rab65 both specifically labeled NHE8 by Western blotting as well as by immunofluorescence microscopy. The immunolocalization pattern in the kidney seen with both antibodies was the same, thereby validating NHE8 specificity. In particular, NHE8 expression was observed on the apical brush-border membrane of all proximal tubules from S1 to S3. The most intense staining was evident in proximal tubules in the deeper cortex and medulla with a significant but somewhat weaker staining in superficial proximal tubules. Colocalization studies with γ-glutamyltranspeptidase and megalin indicated expression of NHE8 on both the microvillar surface membrane and the coated-pit region of proximal tubule cells, suggesting that NHE8 may be subject to endocytic retrieval and recycling. Although colocalizing in the proximal tubule with NHE3, no significant alteration in NHE8 protein expression was evident in NHE3-null mice. We conclude that NHE8 is expressed on the apical brush-border membrane of proximal tubule cells, where it may play a role in mediating or regulating ion transport in this nephron segment.
Abnormal Myocardial Presynaptic Norepinephrine Recycling in Patients With Brugada Syndrome
Authors: Kies Peter , Wichter Thomas , Schäfers Michael , Paul Matthias , Schäfers Klaus P. , Eckardt Lars , Stegger Lars , Schulze-Bahr Eric , Rimoldi Ornella , Breithardt Günter , Schober Otmar , Camici Paolo G.
Published: November 2004

Background—

Life-threatening ventricular tachyarrhythmias can occur in young patients without structural heart disease (idiopathic forms). In many patients, these are typically triggered by an increased sympathetic tone, eg, by physical or mental stress. In contrast, in Brugada syndrome, ventricular tachyarrhythmias more often occur during rest or sleep when the vagal tone is predominant. Furthermore, adrenergic agonists can reduce the level of ST-segment elevation, whereas it is increased by parasympathetic agonists or adrenergic antagonists. The aim of this study was to investigate presynaptic and postsynaptic myocardial sympathetic function in patients with Brugada syndrome.

Methods and Results—

Nine patients with Brugada syndrome (6 male, 3 female; age, 41±13 years) were enrolled in this study. The cardiac autonomic nervous system was assessed noninvasively, quantifying myocardial presynaptic and postsynaptic sympathetic function by means of positron emission tomography with the norepinephrine analogue
11
C-Hydroxyephedrine (
11
C-HED) and the nonselective β-blocker
11
C-CGP 12177 (
11
C-CGP). Presynaptic sympathetic norepinephrine recycling, assessed by
11
C-HED, was globally increased in patients with Brugada syndrome compared with a group of age-matched healthy control subjects (92.9±16.2 mL/g versus 69.1±14.2 mL/g;
P
<0.05), whereas postsynaptic β-adrenoceptor density, assessed by
11
C-CGP, was similar in patients and control subjects (10.4±6.7 pmol/g versus 10.2±2.9 pmol/g;
P
=NS).

Conclusions—

The present study on autonomic innervation in Brugada syndrome describes an enhanced presynaptic norepinephrine recycling with preserved β-adrenoceptor density, further supporting the hypothesis of an autonomic dysfunction in Brugada syndrome. This is a further step toward the understanding of the pathophysiology of the disease with potential future impact on therapeutic strategies.
Galectin-3 Marks Activated Macrophages in Failure-Prone Hypertrophied Hearts and Contributes to Cardiac Dysfunction
Authors: Sharma Umesh C. , Pokharel Saraswati , van Brakel Thomas J. , van Berlo Jop H. , Cleutjens Jack P.M. , Schroen Blanche , André Sabine , Crijns Harry J.G.M. , Gabius Hans -J. , Maessen Jos , Pinto Yigal M.
Published: November 2004

Background—

Inflammatory mechanisms have been proposed to be important in heart failure (HF), and cytokines have been implicated to add to the progression of HF. However, it is unclear whether such mechanisms are already activated when hypertrophied hearts still appear well-compensated and whether such early mechanisms contribute to the development of HF.

Methods and Results—

In a comprehensive microarray study, galectin-3 emerged as the most robustly overexpressed gene in failing versus functionally compensated hearts from homozygous transgenic TGRmRen2-27 (Ren-2) rats. Myocardial biopsies obtained at an early stage of hypertrophy before apparent HF showed that expression of galectin-3 was increased specifically in the rats that later rapidly developed HF. Galectin-3 colocalized with activated myocardial macrophages. We found galectin-3-binding sites in rat cardiac fibroblasts and the extracellular matrix. Recombinant galectin-3 induced cardiac fibroblast proliferation, collagen production, and cyclin D1 expression. A 4-week continuous infusion of low-dose galectin-3 into the pericardial sac of healthy Sprague-Dawley rats led to left ventricular dysfunction, with a 3-fold differential increase of collagen I over collagen III. Myocardial galectin-3 expression was increased in aortic stenosis patients with depressed ejection fraction.

Conclusions—

This study shows that an early increase in galectin-3 expression identifies failure-prone hypertrophied hearts. Galectin-3, a macrophage-derived mediator, induces cardiac fibroblast proliferation, collagen deposition, and ventricular dysfunction. This implies that HF therapy aimed at inflammatory responses may need to be targeted at the early stages of HF and probably needs to antagonize multiple inflammatory mediators, including galectin-3.
Long-Term Amiodarone Administration Remodels Expression of Ion Channel Transcripts in the Mouse Heart
Authors: Le Bouter Sabrina , El Harchi Aziza , Marionneau Céline , Bellocq Chloé , Chambellan Arnaud , van Veen Toon , Boixel Christophe , Gavillet Bruno , Abriel Hugues , Le Quang Khai , Chevalier Jean-Christophe , Lande Gilles , Léger Jean J. , Charpentier Flavien , Escande Denis , Demolombe Sophie
Published: November 2004

Background—

The basis for the unique effectiveness of long-term amiodarone treatment on cardiac arrhythmias is incompletely understood. The present study investigated the pharmacogenomic profile of amiodarone on genes encoding ion-channel subunits.

Methods and Results—

Adult male mice were treated for 6 weeks with vehicle or oral amiodarone at 30, 90, or 180 mg · kg
−1
· d
−1
. Plasma and myocardial levels of amiodarone and
N
-desethylamiodarone increased dose-dependently, reaching therapeutic ranges observed in human. Plasma triiodothyronine levels decreased, whereas reverse triiodothyronine levels increased in amiodarone-treated animals. In ECG recordings, amiodarone dose-dependently prolonged the RR, PR, QRS, and corrected QT intervals. Specific microarrays containing probes for the complete ion-channel repertoire (IonChips) and real-time reverse transcription–polymerase chain reaction experiments demonstrated that amiodarone induced a dose-dependent remodeling in multiple ion-channel subunits. Genes encoding Na
+
(SCN4A, SCN5A, SCN1B), connexin (GJA1), Ca
2+
(CaCNA1C), and K
+
channels (KCNA5, KCNB1, KCND2) were downregulated. In patch-clamp experiments, lower expression of K
+
and Na
+
channel genes was associated with decreased I
to,f
, I
K,slow
, and I
Na
currents. Inversely, other K
+
channel α- and β-subunits, such as KCNA4, KCNK1, KCNAB1, and KCNE3, were upregulated.

Conclusions—

Long-term amiodarone treatment induces a dose-dependent remodeling of ion-channel expression that is correlated with the cardiac electrophysiologic effects of the drug. This profile cannot be attributed solely to the amiodarone-induced cardiac hypothyroidism syndrome. Thus, in addition to the direct effect of the drug on membrane proteins, part of the therapeutic action of long-term amiodarone treatment is likely related to its effect on ion-channel transcripts.
Simvastatin Prevents Vascular Hyporeactivity During Inflammation
Authors: Pleiner Johannes , Schaller Georg , Mittermayer Friedrich , Zorn Stefan , Marsik Claudia , Polterauer Stefan , Kapiotis Stylianos , Wolzt Michael
Published: November 2004

Background—

There is growing evidence that statins exert anti-inflammatory and antioxidative vascular actions that are independent of lipid lowering. We tested whether hyporeactivity to the endothelium-dependent vasodilator acetylcholine (ACh) and the vasoconstrictor norepinephrine (NE) during acute experimental inflammation could be prevented by simvastatin.

Methods and Results—

In a randomized, placebo-controlled, parallel group study, forearm blood flow (FBF) responses to NE, ACh, and the endothelium-independent vasodilator nitroglycerin (NTG) were assessed at baseline, after 4 days of simvastatin 80 mg PO or placebo treatment, and during
Escherichia coli
endotoxin (lipopolysaccharide [LPS])–induced inflammation in 20 healthy volunteers. Additionally, markers of inflammation and neutrophil oxidative burst were assessed. Simvastatin and placebo had no effect on FBF or oxidative/inflammatory markers. LPS administration decreased the responses of FBF to NE by 43% (
P
<0.05) and decreased responses to ACh by 48% (
P
<0.05) but did not decrease FBF responses to NTG. Simvastatin completely preserved responses to NE and to ACh. The LPS-induced increases in neutrophil oxidative burst and plasma tumor necrosis factor-α concentrations were mitigated by simvastatin (
P
<0.05 versus placebo).

Conclusions—

This study demonstrates potent vasoprotective properties of high-dose simvastatin during endotoxemia that may be useful for patients with acute systemic inflammation and associated vascular hyporeactivity.
Extracorporeal Cardiac Shock Wave Therapy Markedly Ameliorates Ischemia-Induced Myocardial Dysfunction in Pigs in Vivo
Authors: Nishida Takahiro , Shimokawa Hiroaki , Oi Keiji , Tatewaki Hideki , Uwatoku Toyokazu , Abe Kohtaro , Matsumoto Yasuharu , Kajihara Noriyoshi , Eto Masataka , Matsuda Takehisa , Yasui Hisataka , Takeshita Akira , Sunagawa Kenji
Published: November 2004

Background—

Prognosis of ischemic cardiomyopathy still remains poor because of the lack of effective treatments. To develop a noninvasive therapy for the disorder, we examined the in vitro and vivo effects of extracorporeal shock wave (SW) that could enhance angiogenesis.

Methods and Results—

SW treatment applied to cultured human umbilical vein endothelial cells significantly upregulated mRNA expression of vascular endothelial growth factor and its receptor Flt-1 in vitro. A porcine model of chronic myocardial ischemia was made by placing an ameroid constrictor at the proximal segment of the left circumflex coronary artery, which gradually induced a total occlusion of the artery with sustained myocardial dysfunction but without myocardial infarction in 4 weeks. Thereafter, extracorporeal SW therapy to the ischemic myocardial region (200 shots/spot for 9 spots at 0.09 mJ/mm
2
) was performed (n=8), which induced a complete recovery of left ventricular ejection fraction (51±2% to 62±2%), wall thickening fraction (13±3% to 30±3%), and regional myocardial blood flow (1.0±0.2 to 1.4±0.3 mL · min
−1
· g
−1
) of the ischemic region in 4 weeks (all
P
<0.01). By contrast, animals that did not receive the therapy (n=8) had sustained myocardial dysfunction (left ventricular ejection fraction, 48±3% to 48±1%; wall thickening fraction, 13±2% to 9±2%) and regional myocardial blood flow (1.0±0.3 to 0.6±0.1 mL · min
−1
· g
−1
). Neither arrhythmias nor other complications were observed during or after the treatment. SW treatment of the ischemic myocardium significantly upregulated vascular endothelial growth factor expression in vivo.

Conclusions—

These results suggest that extracorporeal cardiac SW therapy is an effective and noninvasive therapeutic strategy for ischemic heart disease.