bluuebunny/crossref_metadata_2025_split huggingface dataset:
Palliative care in a coronary care unit: a qualitative study of physicians’ and nurses’ perceptions
Authors: Nordgren Lena , Olsson Henny 
Published: December 2004

Background.  Earlier research has shown that physicians and nurses are motivated to provide good palliative care, but several factors prevail that prevent the best care for dying patients. To provide good palliative care it is vital that the relationship between nurses and physicians is one based on trust, respect and sound communication. However, in settings such as a coronary care unit, disagreement sometimes occurs between different professional groups regarding care of dying patients.Aim and objectives.  The aim of this study was to describe and understand physicians’ and nurses’ perceptions on their working relationship with one another and on palliative care in a coronary care unit setting.Design.  Using a convenience sample, professional caregivers were interviewed at their work in a coronary care unit in Sweden.Methods.  Data collection and analysis were done concurrently using a qualitative approach.Results.  From the interviews, a specific pattern of concepts was identified. The concepts were associated with a dignified death, prerequisites for providing good palliative care and obstacles that prevented such care.Conclusions.  Caregivers who work in a coronary care unit are highly motivated to provide the best possible care and to ensure a dignified death for their patients. Nevertheless, they sometimes fail in their intentions because of several obstacles that prevent good quality care from being fully realized.Relevance to clinical practice.  To improve practice, more attention should be paid to increasing dying patients’ well‐being and participation in care, improving strategic decision‐making processes, offering support to patients and their relatives, and improving communication and interaction among caregivers working in a coronary care unit. Caregivers will be able to support patients and relatives better if there are good working relations in the work team and through better communication among the various professional caregivers.
Feeding Experience Modifies the Assessment of Ambush Sites by the Timber Rattlesnake, a Sit‐and‐Wait Predator
Authors: Clark Rulon W. 
Published: December 2004

AbstractTo effectively ambush prey, sit‐and‐wait predators must locate sites where profitable prey are likely to return. One means by which predators evaluate potential ambush sites is by recognizing high‐use areas through chemical cues deposited inadvertently by their prey. However, it is unknown whether ambush predators can use chemical cues associated with past prey items in the assessment of potential ambush sites. I examined selection of ambush sites by timber rattlesnakes (Crotalus horridus) exposed to trails made from chemical extracts of the integument of various prey species. I evaluated the role of feeding experience in ambush site selection by comparing the behavior of timber rattlesnakes before and after feeding experience with different sized prey items. Timber rattlesnakes are more likely to select ambush sites adjacent to chemical trails from prey with which they have had feeding experience, but only those fed relatively large prey showed an increase in responsiveness. Increased responsiveness after feeding experience was exhibited in experiments using integumentary extracts of mammals (the natural prey of timber rattlesnakes), but not in those using extracts of fish. These results indicate that ambush predators may learn to recognize chemicals on the integument of profitable food items, and use that experience when subsequently selecting ambush sites. Additionally, these findings provide evidence that size‐dependent predation by snakes may be, in some species, a result of active prey selection.
Increase in meso‐prefrontal dopaminergic activity after stimulation of CB1 receptors by cannabinoids
Authors: Diana M. , Melis M. , Gessa G. L. 
Published: December 2004

AbstractThe intravenous administration of the psychoactive constituent of marijuana, Δ9‐tetrahydrocannabinol (Δ9‐THC) (62.5–1000 μg/kg), and the synthetic cannabinoid agonist WIN 55212,2 (WIN) (62.5–500 μg/kg), produced a dose‐related increase in the firing rate and burst firing in the majority of antidromically identified meso‐prefrontal dopaminergic neurons.  In a restricted number of neurons (n = 4), WIN administration did not increase firing rate but produced an increment of bursting activity. These effects of the cannabinoids were reversed by the intravenous administration of SR 141716 A, a selective cannabinoid antagonist (1 mg/kg), per se ineffective to modify the electrical activity of dopaminergic neurons.  The results indicate that stimulation of cannabinoid CB1 receptors produces an activation of meso‐prefrontal dopaminergic transmission.  Considering that supranormal stimulation of D1 dopamine receptors in the prefrontal cortex has been shown to impair working memory, the present results suggest that the negative effects of cannabinoids on cognitive processes might be related to the activation of dopaminergic transmission in the prefrontal cortex.
A novel form of long‐term depression in the CA1 area of the adult rat hippocampus independent of glutamate receptors activation
Authors: Berretta Nicola , Cherubini Enrico 
Published: December 2004

AbstractIn young rats, low frequency (1–2 Hz) stimulation of the Schaffer collaterals for 15 min induces in the CA1 area of the hippocampus a homosynaptic and N‐methyl‐d‐aspartate receptor‐dependent form of long‐term depression (LTD) of synaptic efficacy. In the adults, while a similar stimulation paradigm is able to depress previously potentiated synapses, it leads to conflicting results when applied to naive synapses. In the present experiments, different stimulation paradigms have been used to induce LTD in the CA1 area of the adult rat hippocampus in vitro. Thus, stimulation of the afferent pathway at frequencies higher than those used to produce LTD in young animals (5–10 Hz, for 15 min) reliably induced a homosynaptic form of LTD. This form of LTD was associated with a significant increase in paired‐pulse facilitation ratio and was insensitive to ionotropic (CNQX, 10 μm and CPP, 20 μm) and metabotropic (S‐MCPG, 1 mm) glutamate receptors antagonists, suggesting a presynaptic mechanism for both LTD induction and expression. In conclusion, our experiments clearly show that LTD is not a purely developmental phenomenon but is present also in mature rats, which possess the whole machinery for LTD induction and this will greatly enhance the flexibility and the storing capacity of neuronal circuits.
β‐adrenergic and fibroblast growth factor receptors induce neuronal process outgrowth through different mechanisms
Authors: Kwon John H. , Weisenhorn Daniela M. Vogt , Downen Martha , Ruan Kesan , Roback Linda , Joshi Harish , Wainer Bruce H. 
Published: December 2004

AbstractThe mechanisms that initiate and direct neuronal process formation remain poorly understood. We have recently described a neuronal progenitor cell line, AS583‐8.E4.22 (AS583‐8) which undergoes neurite formation in response to β2‐adrenergic and basic fibroblast growth factor (bFGF) receptor activation [Kwon, J.H et al. (1996) Eur. J. Neurosci., 8, 2042–2055]. In the present study, a comparison of these responses revealed that isoproterenol (ISO), a β‐adrenergic receptor agonist, induces multiple, highly branched processes within 30 min while bFGF induces fewer, unbranched processes within 24 h. In contrast to the ISO response, bFGF induces mitogen‐activated protein kinase activation and c‐fos expression in the cell line and results in neurite outgrowth that is dependent on new mRNA and protein synthesis. Two‐dimensional isoelectric focusing‐sodium dodecyl sulphate–polyacrylamide gel electrophoresis of cytoskeletal preparations revealed different patterns following ISO vs. bFGF exposure suggesting selective changes in protein expression and/or post‐translational modifications. Immunoblot analysis of these preparations for β‐tubulin, tyrosinated α‐tubulin and acetylated α‐tubulin also revealed different patterns following each type of treatment. Follow‐up confocal microscopy revealed that following ISO, the distribution of tyrosinated tubulin extends to the distal ends of processes whereas acetylated α‐tubulin is diminished within distal ends. This pattern has been reported to be associated with enhanced microtubule dynamics, a state in which process outgrowth is facilitated. In contrast, following bFGF treatment the distributions of tyrosinated and acetylated α‐tubulin were identical, a state associated with a diminution of microtubule dynamics. These results, a different time course of neurite formation, dependency on new gene expression and differential expression and cellular distribution of major cytoskeleton proteins suggest that neurite outgrowth induced by ISO vs. bFGF is mediated by two distinct intracellular effector mechanisms in AS583‐8 cells. In addition, studies, using the differential distribution of post‐translational modified α‐tubulins in neurites of primary neuronal cultures as marker for the two distinct processes of neurite formation suggest, that similar mechanisms are present in vivo. Therefore, the AS583‐8 cell line provides a useful model to study these signalling mechanisms that couple neurotransmitter and growth factor receptor activation to the cytoskeletal changes that mediate neurite formation.
SR141716A reduces the reinforcing properties of heroin but not heroin‐induced increases in nucleus accumbens dopamine in rats
Authors: Caillé Stéphanie , Parsons Loren H. 
Published: December 2004

AbstractThe present experiments tested the hypothesis that the selective CB1 receptor antagonist SR141716A alters heroin self‐administration by attenuating heroin‐induced increases in nucleus accumbens dopamine levels. SR141716A pretreatment dose‐dependently (0.3–3 mg/kg, i.p.) reduced operant heroin self‐administration by male Wistar rats under a fixed ratio schedule of reinforcement, and significantly lowered the breaking point of responding for heroin under a progressive ratio schedule of reinforcement. These observations are consistent with recent reports that CB1 receptor inactivation reduces the rewarding properties of opiates. Operant responding for water reinforcement by water‐restricted rats was unaltered by these SR141716A doses. Microdialysis tests revealed that heroin self‐administration significantly increases interstitial dopamine levels in the nucleus accumbens shell of vehicle‐pretreated control rats. However, whereas SR141716A pretreatment dose‐dependently reduced heroin self‐administration, it did not alter the heroin‐associated increase in nucleus accumbens dopamine. These findings suggest that the CB1 antagonist‐induced attenuation of heroin reward does not involve dopaminergic mechanisms in the nucleus accumbens shell.
SK channels and the varieties of slow after‐hyperpolarizations in neurons
Authors: Vogalis Fivos , Storm Johan F. , Lancaster Barrie 
Published: December 2004

AbstractAction potentials and associated Ca2+ influx can be followed by slow after‐hyperpolarizations (sAHPs) caused by a voltage‐insensitive, Ca2+‐dependent K+ current. Slow AHPs are a widespread phenomenon in mammalian (including human) neurons and are present in both peripheral and central nervous systems. Although, the molecular identity of ion channels responsible for common membrane potential mechanisms has been largely determined, the nature of the channels that underlie the sAHPs in neurons, both in the brain and in the periphery, remains unresolved. This short review discusses why there is no clear molecular candidate for sAHPs.
In vivo dynamic ME‐MRI reveals differential functional responses of RA‐ and area X‐projecting neurons in the HVC of canaries exposed to conspecific song
Authors: Tindemans I. , Verhoye M. , Balthazart J. , Van der Linden A. 
Published: December 2004

AbstractHVC (nidopallial area, formerly known as hyperstriatum ventrale pars caudalis), a key centre for song control in oscines, responds in a selective manner to conspecific songs as indicated by electrophysiology. However, immediate–early gene induction cannot be detected in this nucleus following song stimulation. HVC contains neurons projecting either towards the nucleus robustus archistriatalis (RA; motor pathway) or area X (anterior forebrain pathway). Both RA‐ and area X‐projecting cells show auditory responses. The present study analysed these responses separately in the two types of HVC projection neurons of canaries by a new in vivo approach using manganese as a calcium analogue which can be transported anterogradely and used as a paramagnetic contrast agent for magnetic resonance imaging (MRI). Manganese was stereotaxically injected into HVC and taken up by HVC neurons. The anterograde axonal transport of manganese from HVC to RA and area X was then followed by MRI during ≈ 8 h and changes in signal intensity in these targets were fitted to sigmoid functions. Data comparing birds exposed or not to conspecific songs revealed that song stimulation specifically affected the activity of the two types of HVC projection neurons (increase in the sigmoid slope in RA and in its maximum signal intensity in area X). Dynamic manganese‐enhanced MRI thus allows assessment of the functional state of specific neuronal populations in the song system of living canaries in a manner reminiscent of functional MRI (but with higher resolution) or of 2‐deoxyglucose autoradiography (but in living subjects).
Tangential migration of cells from the basal to the dorsal telencephalic regions in the chick
Authors: Tuorto F. , Alifragis P. , Failla V. , Parnavelas J. G. , Gulisano M. 
Published: December 2004

AbstractThe evolutionary relationship between telencephalic regions of the avian and mammalian brains has been a long‐standing issue in comparative neuroanatomy. Based on various criteria, a number of homologous regions have been proposed. Recent studies in mammals have shown that basal regions of the telencephalon give rise to neurons that migrate dorsally and populate the cerebral cortex. In the present study we demonstrate that, similar to mammals, neurons from a ventricular region of the palaeo‐striatal complex – the dorsal subpallial sulcus – of the chick telencephalon migrate dorsally to populate the developing pallium. Further characterization of these cells revealed that they express the neurotransmitter γ‐aminobutyric acid, but not the calcium‐binding protein calbindin. These findings provide evidence that the mouse and chick basal regions are not only homologous in terms of gene expression patterns and connectivity, but they both also contribute inhibitory interneurons to dorsal regions of the developing telencephalon.
Alike performance during nonverbal episodic learning from diversely imprinted neural networks
Authors: Grön Georg , Schul David , Bretschneider Volker , Wunderlich A. P. , Riepe Matthias W. 
Published: December 2004

AbstractPerformance on neuropsychological testing permits inferences to be made regarding neural networks required to solve the task. In healthy young human subjects it is common sense that differential performance in cognitive tasks results from recruitment of different neural networks and that alike performance results from recruitment of alike neural networks. It was the goal of the present study to investigate whether these assumptions are also valid in cross‐cultural studies. To address this, we used functional MRI during a nonverbal episodic memory task with repeated learning of abstract geometric patterns. Behavioural performance in this task was alike over repeated trials in native Chinese and Caucasian subjects. Given this equivalent performance, the distinct pattern of neuronal activation observed is interpreted as the outcome of different culturally imprinted processing routines. In the ‘what’ and ‘where’ framework of visuo‐spatial processing initial learning in Chinese subjects activated the dorsal stream for analysis of spatial features whereas Caucasians recruited the ventral stream for object identification. With repeated learning Chinese subjects integrated visuo‐spatial processing to object coding and vice versa. Thus, imprints of culture result in activation of distinct neural networks and mandate monitoring of both behavioural performance and neural recruitment in cross‐cultural studies of cognition.
Evidence for vesicular glutamate transporter synapses onto gonadotropin‐releasing hormone and other neurons in the rat medial preoptic area
Authors: Kiss J. , Kocsis K. , Csáki Á. , Halász B. 
Published: December 2004

AbstractThe medial preoptic area is a key structure in the control of reproduction. Several data suggest that excitatory amino acids are involved in the regulation of this function and the major site of this action is the medial preoptic region. Data concerning the neuromorphology of the glutamatergic innervation of the medial preoptic area are fragmentary. The present investigations were focused on: (i) the morphology of the vesicular glutamate transporter 1 (VGluT1)‐ and vesicular glutamate transporter 2 (VGluT2)‐immunoreactive nerve terminals, which are considered to be specific to presumed glutamatergic neuronal elements, in the medial preoptic area of rat; and (ii) the relationship between these glutamate transporter‐positive endings and the gonadotropin‐releasing hormone (GnRH) neurons in the region. Single‐ and double‐label immunocytochemistry was used at the light and electron microscopic level. There was a weak to moderate density of VGluT1‐ and a moderate to intense density of VGluT2‐immunoreactive elements in the medial preoptic area. Electron microscopy revealed that both VGluT1‐ and VGluT2‐immunoreactive boutons made asymmetric type synaptic contacts with unlabelled neurons. VGluT2‐labelled, but not VGluT1‐labelled, axon terminals established asymmetric synaptic contacts on GnRH‐immunostained neurons, mainly on their dendrites. The present findings are the first electron microscopic examinations on the glutamatergic innervation of the rat medial preoptic area. They provide direct neuromorphological evidence for the existence of direct glutamatergic innervation of GnRH and other neurons in the rat medial preoptic area.
Behavioural adaptations to addictive drugs in mice lacking the NMDA receptor ε1 subunit
Authors: Miyamoto Yoshiaki , Yamada Kiyofumi , Nagai Taku , Mori Hisashi , Mishina Masayoshi , Furukawa Hiroshi , Noda Yukihiro , Nabeshima Toshitaka 
Published: December 2004

Abstract N‐methyl‐d‐aspartate (NMDA) receptors, a subtype of glutamate receptors (GluRs) formed by assembly of the GluRζ subunit (called NR1 in rats) with any one of four GluRε subunits (GluRε1–4; NR2A–D), play an important role in excitatory neurotransmission, synaptic plasticity and brain development. Recent pharmacological studies have also indicated a role for NMDA receptors in drug addiction. In the present study, we investigated the behavioural adaptations to addictive drugs such as phencyclidine (PCP), methamphetamine (MAP) and morphine (MOR) in mice lacking the GluRε1 subunit of the NMDA receptor. GluRε1 mutant mice exhibited a malfunction of NMDA receptors, as evidenced by the reduction of [3H]MK‐801 binding in an autoradiographic receptor binding assay. GluRε1 mutant mice showed an attenuation of acute PCP‐ and MAP‐induced hyperlocomotion. The development of sensitization by repeated treatment with PCP and MAP at a low, but not high, dose was also suppressed. The development of MOR‐induced analgesic tolerance and naloxone‐precipitated MOR withdrawal symptoms were attenuated in GluRε1 mutant mice. In the place conditioning test, PCP‐induced place aversion in naive mice and place preference in PCP‐pretreated mice, as well as MOR‐induced place preference, were diminished whereas MAP‐induced place preference was not affected in GluRε1 mutant mice. These findings provide genetic evidence that GluRε1 subunit‐containing NMDA receptors are involved in certain aspects of drug addiction.
Effect of gene transfer of GLT‐1, a glutamate transporter, into the locus coeruleus by recombinant adenoviruses on morphine physical dependence in rats
Authors: Ozawa Tohru , Nakagawa Takayuki , Sekiya Yumiko , Minami Masabumi , Satoh Masamichi 
Published: December 2004

AbstractThere is a body of evidence implying the involvement of the central glutamatergic system in morphine dependence. We previously reported changes in the mRNA expression of a glial glutamate transporter GLT‐1 in some brain regions of morphine‐dependent and naloxone‐precipitated withdrawal rats, and inhibition of morphine physical dependence by a glutamate transporter activator in mice. These findings support the possibility that glutamate transporters such as GLT‐1 are involved in morphine dependence. In this study, we examined the effects of gene transfer of GLT‐1 into the locus coeruleus (LC) by recombinant adenoviruses on morphine physical dependence in rats. We constructed recombinant adenoviruses that successfully delivered the GLT‐1 gene in vitro and in vivo. Local overexpression of GLT‐1 within the bilateral LC by the recombinant adenoviruses before implantation of the morphine pellet significantly inhibited various somatic signs of naloxone‐precipitated morphine withdrawal, compared with the control. These results suggest that GLT‐1 within the LC plays an inhibitory role in morphine physical dependence.
Execution and observation of bringing a fruit to the mouth affect syllable pronunciation
Authors: Gentilucci Maurizio , Santunione Paola , Roy Alice C. , Stefanini Silvia 
Published: December 2004

AbstractKinematic analysis of lip and voice spectrum analysis were used to assess the influence of both execution and observation of arm–mouth‐related actions on speech production. In experiments 1 and 2 participants brought either a cherry or an apple to their mouth and either pronounced the syllable BA (experiment 1) or emitted a nonspeech‐related vocalization (experiment 2). In the other three experiments participants observed arm actions performed by the experimenter and pronounced the syllable BA. In experiment 3, they observed the action of bringing the cherry or apple to the mouth. In experiments 4 and 5, they observed a pantomime of the same action performed by the experimenter with his own arm (experiment 4) or with a nonbiological arm (experiment 5). The results showed that the formant 2 of the vowel ‘a’ increased when participants executed the bringing‐to‐the‐mouth act with the apple or observed its execution or pantomime with the experimenter's arm (experiments 1, 3 and 4). In contrast, no modification in the vowel formants was found during a nonspeech‐related vocalization (experiment 2) and during observation of an action with a nonbiological arm (experiment 5). Finally, the opening of the lips was larger when the participant brought the apple rather than the cherry to the mouth and pronounced BA (experiment 1). Taken together, the results of the present study suggest that the execution and observation of the bringing‐to‐the‐mouth action activate a mouth articulation posture (probably due to the act of food manipulation with the mouth) which selectively influences speech production. They support the idea that the system involved in speech production shares and may derive from the neural substrate which is involved in the control of arm–mouth interactions and, in general, of arm actions.