bluuebunny/crossref_metadata_2025 huggingface dataset:
Adolescent stress and neural plasticity in hamsters: a vasopressin‐serotonin model of inappropriate aggressive behaviour
Authors: Ferris Craig F.
Published: April 2005

Animal studies show that arginine vasopressin facilitates aggression, while serotonin (5‐HT) inhibits aggression by blocking the activity of the vasopressin system. Clinical studies report that subjects with a history of ‘fighting and assault’ show a significant positive correlation between cerebrospinal fluid concentrations of vasopressin and aggression in the presence of a hyporeactive 5‐HT system. Thus, in animals and humans, a hyporeactive 5‐HT system may result in enhanced vasopressin activity and increased aggression. Can the stress of emotional and physical insult, i.e. threat and attack, during adolescence affect the development of the vasopressin and 5‐HT systems and alter normal aggressive behaviour in early adulthood? Adolescent male golden hamsters were weaned at postnatal day 25, and stressed for 2 weeks by daily 1 h bouts of threat and attack by adult hamsters. Male littermates were run in a parallel stress study using daily 1 h trials of isolation in a novel environment. During early adulthood, on postnatal day 45, 3 days after the cessation of stress trials, animals were tested for aggression in a resident: intruder model. The results show a context‐dependent change in aggression. Animals with a history of abuse show exaggerated attack behaviour toward smaller males compared to littermates with a history of isolation stress. Conversely, when confronted by males of equal size, animals with a history of abuse show diminished aggression and increased submission compared to controls. It was determined that the density of vasopressin fibres and neurones in the hypothalamus is lower in abused animals compared to controls. In contrast, the number of 5‐HT terminals within the hypothalamus is higher in abused animals compared to controls. These results provide evidence in an animal model that stress in the form of threat and attack during adolescence can alter the balance between vasopressin and 5‐HT in the brain, resulting in inappropriate aggressive behaviour in early adulthood.
The role of oxytocin and regulation of uterine oxytocin receptors in pregnant marsupials
Authors: Parry Laura J. , Bathgate Ross A. D.
Published: April 2005

The oxytocin‐like peptide of most Australian marsupials is mesotocin, which differs from oxytocin by a single amino acid. This substitution has no functional significance as both peptides have equivalent affinity for and biological activity on the marsupial oxytocin‐like receptor. A role for mesotocin in marsupial parturition has been demonstrated in the tammar wallaby where plasma mesotocin concentrations increase less than one minute before birth. Infusion of an oxytocin receptor antagonist at the end of gestation disrupts normal parturition, probably by preventing mesotocin from stimulating uterine contractions. In the absence of mesotocin receptor activation, a peripartum surge in prostaglandins is delayed which suggests a functional relationship between mesotocin, prostaglandin release and luteolysis. Female marsupials have anatomically separate uteri and in monovular species, such as the tammar wallaby, only one uterus is gravid with a single fetus whereas the contralateral uterus remains non‐gravid. We have used this unique animal model to differentiate systemic and fetal‐specific factors in the regulation of uterine function during pregnancy. The gravid uterus in the tammar wallaby becomes increasingly sensitive to mesotocin as gestation proceeds, with the maximum contractile response observed at term. This is reflected in a large increase in mesotocin receptor concentrations in the gravid uterus, and a downregulation in the non‐gravid uterus in late pregnancy. The upregulation in myometrial mesotocin receptors is pregnancy‐specific and independent of systemic steroids. One factor that may influence mesotocin receptor upregulation in the gravid uterus in late pregnancy is mechanical stretch of the uterus caused by the growing fetus. Our data highlight that a local fetal influence is more important than systemic factors in the regulation of mesotocin receptors in the tammar wallaby.
Catecholaminergic mechanisms underlying neurohypophysial hormone responses to unconditioned or conditioned aversive stimuli in rats
Authors: Onaka Tatsushi
Published: April 2005

Oxytocin release from the neurohypophysis is facilitated by systemic cholecystokinin octapeptide (CCK) administration and noxious stimuli. Oxytocin release after CCK administration is mediated by A2 noradrenergic neurones while the release after noxious stimuli appears to be mediated by A1 noradrenergic neurones. On the other hand, facilitation of vasopressin release after noxious stimuli is not dependent upon noradrenergic neurones but on dopamine receptors. Environmental stimuli previously paired with noxious stimuli (conditioned fear stimuli) or novel environmental stimuli facilitate oxytocin release and suppress vasopressin release. These neuroendocrine responses to conditioned fear stimuli, but not to novel stimuli, are impaired by central noradrenaline depletion or i.c.v. adrenoceptor antagonists. These data suggest that there are at least two types of stress responses in neuroendocrine systems, one noradrenaline dependent, and one noradrenaline independent. It is also suggested that noradrenergic neurones are functionally heterogeneous in the control of oxytocin release.
Oxytocin, motherhood and bonding
Authors: Kendrick Keith. M.
Published: April 2005

Release of the peptide hormone oxytocin in the brain has been shown to influence both maternal, sexual and social bonding behaviours although there are a number of species differences. This review summarizes findings on the distributions of oxytocin and oxytocin receptors in the brain, together with factors governing their expression, release of the peptide in the brain and its behavioural actions. A model of how oxytocin may act to alter maternal and socio‐sexual behaviours is proposed which initially involves activation of oxytocin neurones in a single brain site, the paraventricular nucleus of the hypothalamus (PVN), following vaginal and cervical stimulation. This causes a co‐ordinated release of the peptide in the PVN and its terminal projection regions for up to 1 h and this promotes different behavioural components, primarily through modulation of classical transmitter systems.
Neurohypophysial peptides as retrograde transmitters in the supraoptic nucleus of the rat
Authors: Pittman Quentin J. , Hirasawa Michiru , Mouginot Didier , Kombian Samuel B.
Published: April 2005

A possible role for vasopressin and oxytocin in the physiology of the supraoptic nucleus was investigated using nystatin‐perforated patch recording in acute brain slices from the rat containing the supraoptic nucleus. We observed that exogenously applied oxytocin reduced glutamate‐mediated synaptic transmission by acting at a presynaptic oxytocin receptor. Endogenous oxytocin, released either by afferent excitation (tetanus) or by postsynaptic depolarization of the recorded magnocellular neurone caused a similar reduction of excitatory input and this could be blocked with an oxytocin antagonist. Thus endogenous oxytocin, released from magnocellular dendrites, acts as a retrograde transmitter to reduce afferent excitation. We discuss the possible significance of these results in terms of the physiological role of oxytocin in the intact animal and suggest possible avenues for further experimentation.
Pre‐ and postsynaptic modulation of the electrical activity of rat supraoptic neurones
Authors: Shibuya Izumi , Kabashima Narutoshi , Ibrahim Nuruhadi , Setiadji Sutarmo V. , Ueta Yoichi , Yamashita Hiroshi
Published: April 2005

The release of vasopressin and oxytocin is regulated by the electrical activity of magnocellular neurosecretory cells in the supraoptic and paraventricular nuclei, which is under the control of a great variety of neuro‐transmitters and neuromodulators. The major neural signals to the supraoptic nucleus are from excitatory glutamate inputs and inhibitory GABA inputs. In recent studies, the voltage‐clamp mode of the whole‐cell patch‐clamp technique has been applied to slice preparations from rat hypothalamus to monitor synaptic inputs to supraoptic neurones. Spontaneous excitatory and inhibitory postsynaptic currents (EPSCs and IPSCs) are abolished by CNQX and picrotoxin, respectively, but are insensitive to tetrodotoxin, indicating that they represent quantal release of glutamate and GABA, respectively, from nerve terminals of presynaptic neurones. GABA and glutamate show remarkable suppressive effects on both EPSCs and IPSCs via presynaptic GABAB and mGlu receptors, respectively. Noradrenaline, which excites supraoptic neurones via postsynaptic α1‐receptors, also suppresses IPSCs and potentiates EPSCs. On the other hand, prostaglandin E2, which excites supraoptic neurones via postsynaptic prostaglandin E2 (EP) receptors of the EP4 subclass, also suppresses IPSCs via EP3 receptors but has little effect on EPSCs. Thus pre‐ and postsynaptic mechanisms may act cooperatively to excite supraoptic neurones. Nitric oxide, which inhibits supraoptic neurones, potentiates IPSCs without affecting EPSCs. This provides another example for the preferential modulation of IPSCs of supraoptic neurones. On the other hand, PACAP, which causes a long‐lasting increase in the firing frequency via the postsynaptic receptors, has no effect on EPSCs and IPSCs, suggesting that some ligands act only at postsynaptic receptors. Thus multiple patterns for pre‐ and postsynaptic modulation are present in the supraoptic nucleus, and the electrical activity of supraoptic neurones is regulated via complex mechanisms at both pre‐ and postsynaptic sites.
Local circuitry regulates the excitability of rat neurohypophysial neurones
Authors: Ferguson Alastair V. , Latchford Kevin J.
Published: April 2005

The importance of angiotensin II (AII) and glutamate has long since been recognized in neuroendocrine regulation. However, the mechanisms by which AII and glutamate modulate the excitability of the paraventricular nucleus (PVN) have largely remained a mystery until recently. It is now apparent that AII and glutamate are potent stimulators of both magnocellular and parvocellular neurones in the rat PVN. While glutamate, the predominant excitatory neurotransmitter in the CNS, ubiquitously excites PVN neurones, AII appears to mediate excitability of the PVN by both direct and indirect mechanisms. Interestingly, both of these neurotransmitters, upon exciting the PVN, activate an inhibitory feedback system, which is capable of diminishing the initial stimulus. Physiologically, this moderates the output signals from the PVN, and probably also regulates neuropeptide release from the neurohypophysis. The importance of this negative‐feedback loop is evident in the pathophysiological implications of a disruption in the system. Evidence suggests that a breakdown in this system may be responsible in part for the onset and maintenance of both congestive heart failure and hypertension. Future studies will continue to characterize both the actions of glutamate and AII in the PVN, and to further elucidate the mechanisms which control the excitability of the PVN.
A physiological role for adrenomedullin in rats; a potent hypotensive peptide in the hypothalamo‐neurohypophysial system
Authors: Ueta Yoichi , Serino Ryota , Shibuya Izumi , Kitamura Kazuo , Kangawa Kenji , Russell John A. , Yamashita Hiroshi
Published: April 2005

Adrenomedullin, a potent hypotensive peptide, was originally isolated from human phaeochromocytoma. Adrenomedullin immunoreactivity and gene expression are found not only in peripheral organs but also in the central nervous system. Adrenomedullin labelled cells were localised in the hypothalamus, including in the paraventricular and supraoptic nuclei, in rats. Abundant adrenomedullin‐immunoreactive fibres and varicosities were found in the hypothalamo‐neurohypophysial tract and the internal zone of the median eminence in colchicine‐treated and hypophysectomized rats, whereas in control rats few adrenomedullin‐labelled fibres were observed. We examined the effects of intracerebroventricular administration of adrenomedullin on neurosecretory cells in the paraventricular and supraoptic nuclei of rats, using immuno‐histochemistry for Fos protein and in situ hybridisation histochemistry for c‐fos mRNA. Intracerebroventricular administration of adrenomedullin caused a marked induction of Fos‐like immunoreactivity in the paraventricular nucleus and the dorsal part of the supraoptic nucleus. In the paraventricular and supraoptic nuclei, nuclear Fos‐like immunoreactivity was predominantly in oxytocin‐immunoreactive cells rather than vasopressin‐immunoreactive cells. The induction of c‐fos mRNA in the paraventricular and supraoptic nuclei was increased in a dose‐related manner 30 min after intracerebroventricular administration of adrenomedullin. This induction was reduced by pre‐treatment with the adrenomedullin receptor antagonist, human adrenomedullin‐(22–52)‐NH2 Intracerebroventricular administration of adrenomedullin also caused a marked increase in the plasma concentration of oxytocin. Extracellular recordings from magnocellular neurosecretory cells in the paraventricular nucleus revealed that putative oxytocin‐secreting cells were activated by intracerebroventricular administration of adrenomedullin. These results suggest that central adrenomedullin preferentially stimulates the secretion of oxytocin by activating hypothalamic oxytocin‐secreting cells and may have an important role in salt appetite and body fluid homeostasis in rats.
Diurnal rhythms in neurohypophysial function
Authors: Forsling Mary L.
Published: April 2005

The neurohypophysial hormones oxytocin and vasopressin show daily rhythms of secretion with elevated hormone release during the hours of sleep. This pattern can be modulated by ovarian steroids and alters with age. The pattern appears to be due in part to the nocturnal increase in melatonin secretion, which stimulates hormone release in man, while being inhibitory in the rat. Pinealectomy alters both the 24 h pattern of neurohypophysial hormone release in the rat and the firing rate of magnocellular supraoptic nucleus neurones. There is also a reduced hormone release in response to hypovolaemia and raised plasma sodium concentration compared to sham operated animals, with a smaller increase in neuronal activity, as determined by immediate‐early gene expression. The normal responses can be restored by nocturnal administration of melatonin. Melatonin also influences the neurohypophysial hormone response in the human to known stimuli of release, such as raised plasma osmolality, exercise and insulin‐induced hypoglycaemia. Recent studies have revealed that not only does the release of vasopressin and oxytocin vary over each 24 h, but the respective renal and pregnant uterine responses also show diurnal variations.
Differential expression of two adhesion molecules of the immunoglobulin superfamily, F3 and polysialylated NCAM, in hypothalamic magnocellular neurones capable of plasticity
Authors: Theodosis Dionysia T. , Pierre Karin , Poulain Dominique A.
Published: April 2005

The adult hypothalamo‐neurohypophysial system undergoes activity‐dependent, reversible morphological changes which result in reduced astrocytic coverage of its neurones and an increase in their synaptic contacts. Our recent observations show that neurones and glia of the hypothalamo‐neurohypophysial system continue to express ‘embryonic’ molecular features which may underlie their capacity to undergo such plasticity. These include expression of cell surface molecules like the glycosyl phosphatidyl inositol (GPI)‐linked glycoprotein F3, which intervenes in axonal outgrowth, and the polysialylated isoform of the neural cell adhesion molecule (PSA‐NCAM), which reduces cell adhesion and promotes dynamic cell interactions. F3 is colocalised with vasopressin and oxytocin hormones in neurosecretory granules and follows an activity‐dependent, regulated pathway for surface expression on neurohypophysial axons. In contrast, PSA‐NCAM appears to follow a constitutive pathway, independent of the activity of the hypothalamo‐neurohypophysial system, for expression on axonal and glial surfaces, in the hypothalamic magnocellular nuclei and in the neurohypophysis. The role of F3 remains to be determined but in view of its presumptive functions during development, we propose that it promotes remodelling of neurosecretory terminals. On the other hand, we provide direct evidence that surface expression of PSA on NCAM is essential to morphological plasticity since its specific enzymatic degradation in vivo inhibited the neuronal‐glial and synaptic changes normally induced by stimulation of secretion from the hypothalamo‐neurohypophysial system.
Mechanisms of glial retraction in the hypothalamo‐neurohypophysial system of the rat
Authors: Salm A. K.
Published: April 2005

It has been known for more than twenty years that changes in glial coverage of magnocellular neurones in the hypothalamo‐neurohypophysial system accompany activation of those neurones. This led to the so‐called ‘glial retraction hypothesis.’However, until recently, little has been established as to how this structural plasticity of astrocytes develops. This paper will explore a number of hypotheses and supporting data concerning these changes.
Control of the renal medullary circulation by vasopressin V1 and V2 receptors in the rat
Authors: Cowley Allen W.
Published: April 2005

Utilization of the acute and chronically instrumented Sprague—Dawley rat model has provided new and informative data about the mechanisms of, and the role that circulating arginine vasopressin plays in, the regulation of blood flow to the renal medulla. Regional changes of blood flow were measured using implanted optical fibres and laser‐Doppler flowmetry techniques. Transcriptional and translational sites of the V1a and V2 receptors were determined in microdissected intrarenal vascular segments from the cortex and medulla. Results from acute and chronic studies indicate the following. First, physiological elevations of plasma vasopressin concentration seen with 48 h of water restriction reduce blood flow to the inner medulla (via V1 receptors) while maintaining a constancy of blood flow to the outer medulla. Reduction of medullary blood flow is necessary to optimize urine osmolality during water restriction. Second, increases of plasma vasopressin concentration of as little as 8 pg ml‐1, which produce no change in baseline arterial pressure or renal cortical blood flow, can lower medullary blood flow selectively and greatly attenuate the arterial pressure—blood flow and pressure—natriuresis relationship. Third, medullary blood flow does not remain reduced in the face of sustained elevations of plasma vasopressin concentration, which appears to be related to the inability of vasopressin to produce a sustained hypertension. Fourth, V1a receptor mRNA and protein are present in the isolated cortical and medullary vasculature, but the V2 receptor mRNA and protein are found only in tubular segments. Levels of V2 receptor mRNA during water restriction were quantified using a competitive RT‐PCR and a deletion mutant RNA transcript to control for the efficiency of the reaction, and Western blot analysis was utilized for quantification of the V2 receptor protein. The results demonstrated a time‐dependent downregulation of the V2 receptor mRNA and protein within the rat kidney, specifically in the outer medulla. Fifth, the vasopressin‐induced vasoconstriction of the medullary vasa recta microvessels was shown to be mediated via V1a receptors, and this response is normally modulated by vasopressin‐stimulated release of nitric oxide (NO), via extravascular (presumably medullary collecting duct) stimulation of V2 receptors. Finally, chronic vasopressin administration (10 days) increased nitric oxide synthase activity in the outer medulla and interstitial NO concentration in the medulla. These changes are essential to provide a constancy of blood flow to the renal medulla and buffer against the hypertensive actions of this potent vasoconstrictor peptide.
The treatment of hyponatraemia using vasopressin antagonists
Authors: Gross Peter , Palm Catrin
Published: April 2005

Hyponatraemia is a frequent electrolyte disorder. It is primarily attributable to vasopressin excess plus sustained fluid intake. Hyponatraemia causes CNS symptoms, especially during the first 2–4 days; these symptoms are related to brain swelling. Hyponatraemia occurs in the setting of liver cirrhosis and congestive cardiac failure, in which it is related to stimulation by low arterial blood pressure acting through baroreceptors. Hyponatraemia also occurs in the syndrome of inappropriate antidiuretic hormone secretion, usually from neoplasms releasing vasopressin. The conventional treatment of hyponatraemia used to be fluid restriction and treatment of the underlying disorder. This kind of treatment has been unreliable, cumbersome and difficult to comply with for the patient. In the future, effective vasopressin V2 antagonists will become available for clinical use in the treatment of hyponatraemia, and are expected to improve the management of hyponatraemia. Pharmacological characteristics and observations of biological effects of three antagonists are reported in the present article.
Tracing functionally identified neurones in a multisynaptic pathway in the hamster and rat using herpes simplex virus expressing green fluorescent protein
Authors: Pyner S. , Cleary J. , McLeish P. , Buchan A. , Coote J. H.
Published: April 2005

Using a genetically modified herpes simplex virus encoding green fluorescent protein we sought to establish if this viral modification could be used in transneuronal tracing studies of the sympathetic nervous system. The herpes simplex virus encoding green fluorescent protein was injected into the adrenal medulla of three hamsters and six rats. After a suitable survival period, neurones in the sympathetic intermediolateral cell column of the thoracolumbar spinal cord, rostral ventral medulla and paraventricular nucleus of the hypothalamus were clearly identified by the presence of a green fluorescence in the cytoplasm of the neurones of both species. Thus, herpes simplex virus encoding green fluorescent protein labelled chains of sympathetic neurones in the hamster and rat and therefore has the potential to be used in transneuronal tracing studies of autonomic pathways in these species.
Functional properties and responses to ischaemia‐reperfusion in Langendorff perfused mouse heart
Authors: Headrick John P. , Peart Jason , Hack Ben , Flood Amanda , Matherne G. Paul
Published: April 2005

Despite minimal model characterisation Langendorff perfused murine hearts are increasingly employed in cardiovascular research, and particularly in studies of myocardial ischaemia and reperfusion. Reported contractility remains poor and ischaemic recoveries variable. We characterised function in C57/BL6 mouse hearts using a ventricular balloon or apicobasal displacement and assessed responses to 10–30 min global ischaemia. We examined the functional effects of pacing, ventricular balloon design, perfusate filtration, [Ca2+] and temperature. Contractility was high in isovolumically functioning mouse hearts (measured as the change in pressure with time (+dP/dt), 6000–7000 mmHg s‐1) and was optimal at a heart rate of ±420 beats min‐1, with the vasculature sub‐maximally dilated, and the cellular energy state high. Post‐ischaemic recovery (after 40 min reperfusion) was related to the ischaemic duration: developed pressure recovered by 82 ± 5%, 73 ± 4%, 68 ± 3%, 57 ± 2% and 41 ± 5% after 10, 15, 20, 25 and 30 min ischaemia, respectively. Ventricular compliance and elastance were both reduced post‐ischaemia. Post‐ischaemic recoveries were lower in the apicobasal model (80 ± 4%, 58 ± 7%, 40 ± 3%, 32 ± 7% and 25 ± 5%) despite greater reflow and lower metabolic rate (pre‐ischaemic myocardial O2 consumption (VO2,myo) 127 ± 15 vs. 198 ± 17 μl O2 min‐1 g‐1), contracture, enzyme and purine efflux. Electrical pacing slowed recovery in both models, small ventricular balloons (unpressurised volumes < 50–60 μl) artificially depressed ventricular function and recovery from ischaemia, and failure to filter the perfusion fluid to < 0.45 μm depressed pre‐ and post‐ischaemic function. With attention to these various experimental factors, the buffer perfused isovolumically contracting mouse heart is shown to be stable and highly energised, and to possess a high level of contractility. The isovolumic model is more reliable in assessing ischaemic responses than the commonly employed apicobasal model.
Spontaneously hypertensive rats exhibit altered cardiovascular and neuronal responses to muscle contraction
Authors: Kramer Jeffery M. , Waldrop Tony G.
Published: April 2005

We examined the cardiovascular and ventrolateral medullary neuronal responses to muscle contraction in the spontaneously hypertensive rat (SHR) and normotensive Wistar‐Kyoto rat (WKY) control. Cardiovascular, respiratory and ventrolateral medullary neuronal responses to muscle contraction evoked by tibial nerve stimulation were recorded. SHRs exhibited significantly larger drops in arterial pressure compared to WKYs in response to muscle contraction (P < 0.05). Basal ventrolateral medulla neuronal discharge rates were similar between the SHR and the WKY groups. A majority of neurons recorded responded to muscle contraction in both the WKY (77%; n= 53) and the SHR groups (68%;n= 62). There was no difference in the percentage of neurons that responded with an increase (∼60%) or decrease (∼40%) in firing rate between hypertensive and normotensive rats. Pulse wave‐triggered averaging techniques showed that most neurons that responded to muscle contraction also possessed a basal firing rhythm temporally related to the cardiac cycle (85% in WKYs, 83% in SHRs). However, decreases in neuronal firing rates in response to muscle contraction were significantly greater in SHRs than WKYs. Therefore, we conclude that muscle contraction unmasks a hyperexcitability of neurons in the ventrolateral medulla of SHRs that parallels the heightened blood pressure responses.
Volume overload left ventricular hypertrophy: effects on coronary microvascular reactivity in rabbits
Authors: Symons J. D. , Gunawardena S. , Kappagoda C. T. , Dhond M. R.
Published: April 2005

The mechanisms controlling the coronary vascular responses of vessels perfusing the left ventricular (LV) myocardium that is hypertrophied from chronic volume overload are unclear. We hypothesised that endothelial function is compromised, and receptor‐mediated contraction is exacerbated, in coronary resistance vessels from rabbits with LV hypertrophy compared to controls. The mitral valve of 10 rabbits was damaged surgically to cause mitral regurgitation and chronic volume overload, resulting in LV hypertrophy (LV hypertrophy rabbits). Echocardiographic assessment at 12 weeks verified that mitral regurgitation was present in LV hypertrophy but not sham‐operated, weight‐ and age‐matched animals (control rabbits; n= 17). Percentage increases from weeks 0 to 12 in LV cross‐sectional area (47 ± 7%vs. 2 ± 8%), LV volume (47 ± 14%vs. 7 ± 10%) and LV mass (27 ± 4%vs. 3 ± 6%), were greater (all P < 0.05) in LV hypertrophy vs. control rabbits, respectively. At 12 weeks, coronary resistance vessel (± 130 μm, internal diameter) reactivity was evaluated using wire myography. Endothelium‐dependent (i.e. acetylcholine, 10‐8‐10‐5 M) and ‐independent (i.e. sodium nitroprusside, 10‐910‐4 M) relaxation, and receptor‐mediated vasocontraction (i.e. endothelin‐1, 10‐11‐10‐7 M) were similar between groups. However, tension development in response to nitric oxide synthase inhibition (10‐6 M NG‐monomethyl‐L‐arginine) was greater (P < 0.05) in LV hypertrophy compared to control rabbits. These results indicate that while coronary resistance vessel function is similar between groups, our estimate of basal nitric oxide production is greater in vessels from LV hypertrzophy than control rabbits.
Acinar degranulation in the rat parotid gland induced by neuropeptides
Authors: Ekström J. , Ekström P.‐F.
Published: April 2005

Vasoactive intestinal peptide (VIP, 4 μg kg‐1 min‐1), substance P (3 μg kg‐1 min‐1) and neurokinin A (2.5 μg kg‐1 min‐1) were infused intravenously for 30 min in anaesthetized rats and the effects of these peptides on the parotid gland were examined. VIP reduced the numerical density of parotid acinar secretory granules, storing proteins, by 29% and the glandular amylase activity by 33%. Substance P reduced the number of secretory granules by 18% but the amylase activity was unchanged. These results make VIP and substance P likely contributors to the parasympathetic non‐adrenergic, non‐cholinergic (NANC)‐evoked parotid acinar degranulation. Neurokinin A, on the other hand, caused no reduction in granular number but reduced the glandular amylase activity by 19%, indicating vesicular protein secretion.
Interstitial pressure gradients around joints; location of chief resistance to fluid drainage from the rabbit knee
Authors: Scott D. , Bertin K. , Poli A. , Levick J. R. , Miserocchi G. A.
Published: April 2005

The hypothesis has been advanced that synovium offers the main resistance to fluid escape from joints, even though it is under 20 μm thick. To test this, fluid was infused into the knee joint cavity of anaesthetised rabbits to set up a pressure gradient, then the profile of periarticular interstitial fluid pressure (Pif) was measured by advancing a micropipette, connected to a servo‐null pressure recorder, in steps through a periarticular tissue ‘window’until the joint cavity was entered. With intra‐articular pressure (Pj) raised to 15 cmH2O (the pressure of an acute joint effusion) the pressure gradient dPif/dx (where x is distance) across the synovial lining was 0.47 ± 0.04 cmH2O μm‐1 (n= 10 joints). This was 23.5‐fold greater than the gradient in the subsynovium (0.02 ± 0.01 cmH2O μm‐1; P < 0.0001, Student's t test), indicating that the hydraulic resistivity of the subsynovium is ≥4% of that of the synovium. The pressure profile was not altered by circulatory arrest. To test the hypothesis further, the effect of a stab perforation of the synovial lining on fluid drainage rate (Qs) was studied. Perforation raised both Qs and the conductance term dQs/dPj, more than 10‐fold (n= 6 joints; P < 0.0001, ANOVA). The results thus support the view that, despite its thinness, the synovial lining offers the main hydraulic resistance to fluid drainage from a synovial joint.
Effects of nitric oxide synthase inhibition on vascular conductance during high speed treadmill exercise in rats
Authors: Musch Timothy I. , McAllister Richard M. , Symons J. David , Stebbins Charles L. , Hirai Tadakazu , Hageman K. Sue , Poole David C.
Published: April 2005

To determine the functional role of nitric oxide (NO) in regulating vascular conductance during high intensity dynamic exercise in skeletal muscles composed of all major fibre types, female Wistar rats (277 ± 4 g; n= 7) were run on a motor‐driven treadmill at a speed and gradient (60 m min‐1, 10% gradient) established to yield maximal oxygen uptake (Vo2,max). Vascular conductance (ml min‐1 (100g)‐1 mmHg‐1), defined as blood flow normalised to mean arterial pressure (MAP), was determined using radiolabelled microspheres during exercise before and after NO synthase (NOS) inhibition with NG‐nitro‐L‐arginine methyl ester (l‐NAME; 10 mg kg‐1, i.a.). The administration of l‐NAME increased MAP from pre‐l‐NAME baseline values, demonstrating that NOS activity is reduced. The administration of l‐NAME also reduced vascular conductance in 20 of the 28 individual hindlimb muscles or muscle parts examined during high speed treadmill exercise. These reductions in vascular conductance correlated linearly with the estimated sum of the percentage of slow twitch oxidative (SO) and fast twitch oxidative glycolytic (FOG) types of fibres in each muscle (Δconductance = ‐0.0082(%SO +%FOG) ‐ 0.0105; r= 0.66; P < 0.001). However, if the reduction in vascular conductance found in the individual hindquarter muscles or muscle parts was expressed as a percentage decrease from the pre‐l‐NAME value (%Δ= (pre‐l‐NAME conductance — post‐l‐NAME conductance)/pre‐l‐NAME conductance × 100), then the reduction in vascular conductance was similar in all muscles examined (average %Δ= ‐23 ± 2%). These results suggest that NO contributes substantially to the regulation of vascular conductance within and among muscles of the rat hindquarter during high intensity exercise. When expressed in absolute terms, the results suggest that the contribution of NO to the regulation of vascular conductance during high intensity exercise is greater in muscles that possess a high oxidative capacity. In contrast, if results are expressed in relative terms, then the contribution of NO to the regulation of vascular conductance during high intensity exercise is similar across the different locomotor muscles located in the rat hindlimb and independent of the fibre type composition.
The attitudes and nutritional knowledge of 11‐ to 12‐year‐olds in Merseyside and Northern Ireland
Authors: Frobisher Clare , Jepson Margaret , Maxwell Sheila M.
Published: April 2005

School is a major area for providing young people with nutritional knowledge and skills. In Northern Ireland home economics (HE) is taught to 11‐ to 12‐year‐olds. The 1988 Education Reform Act introduced the national curriculum and HE as a subject was effectively abolished in English schools, and key stage 3 pupils in England are taught nutrition in Science, Design and Technology and in the cross curricular theme of health education. The aim of the study was to compare the attitudes and nutritional knowledge of children in Merseyside, England (M) and Northern Ireland (NI). A questionnaire was designed, which examined attitudes to aspects of healthy eating and tested the subject's knowledge, practical and theoretical, on nutrition and healthy eating. Subjects aged 11–12 years were recruited (M: 541, NI: 128). The majority ‘understood and knew what to eat to have a healthy diet’, ‘liked the taste of healthy food’ and considered that ‘there were healthy foods at home’. However, a significantly greater number in Merseyside agreed that ‘their health will be affected in the future by what they eat now’ (M: 71%, NI: 54%, P < 0.01) and agreed that ‘they enjoyed cooking’ (M: 76%, NI: 56%, P < 0.01). Whereas more from Northern Ireland agreed that ‘they do not know what foods to eat to have a healthy diet’ (M: 14%, NI: 30%, P < 0.01), ‘that healthy eating involved “dieting” ’ (M: 29%, NI: 59%, P < 0.01) and agreed that ‘there are no healthy food choices at school’ (M: 23% NI: 42%, P < 0.01). More subjects from Merseyside disagreed that ‘healthy eating is a waste of time’ (M: 87%, NI: 77%, P < 0.01). The mean knowledge scores (correct answers) from Merseyside were significantly greater than from Northern Ireland (total score: M: 51%, NI: 43%P < 0.05; practical score: M: 58%, NI: 49%P < 0.05, theory score: M: 38%, NI: 31%, P < 0.05). The results indicate that the healthy food message seems to have been better learnt by children in Merseyside but results of surveys in Merseyside into eating habits suggest that many have not put this knowledge into practice.
An experimental investigation of the Egyptian consumers’ attitudes towards surrealism in advertising
Authors: Mostafa Mohamed M.
Published: April 2005

This study investigates Egyptian consumers’ attitudes towards surrealism in advertising held by a sample of 976 participants. An experimental approach was taken to establish the interaction between Surreal advertisements and product category attitudes. This interaction was found to be statistically significant. A 2 × 2 anova was conducted to evaluate the effect of sex on attitudes towards surrealism in advertising. The results indicated a significant interaction between advertisement type and sex. However, the impact of surrealism in advertisements on persuasion, as measured by consumers’ attitudes towards the advertisement and brand, was not found to be moderated by consumers’ social class/income. These results lend strong support to the advertisement adaptation hypothesis and suggest that advertisements produced in one country cannot be standardized or directly translated for use in another, particularly if they are culturally different.
Repertoire of strategies used by French Canadian mothers living in Montreal to pressure their 10‐year‐old children to eat
Authors: Marquis Marie , Claveau Dominique
Published: April 2005

This study is concerned with mothers’ use of strategies directed toward their 10‐year‐old children to pressure them to eat. The objective is to document the repertoire of strategies and their context of use. This child‐feeding practice is of interest because of its impact on the child's opportunities for the development of self‐control based on responsiveness to hunger and satiety cues. A total of 24 interviews and one focus group were conducted with French Canadian mothers. Data analyses reveal four major themes associated with the contexts in which pressure to eat were used: food purchasing, food preparation, meal service, food consumption. Strategies related to the context of food purchasing stress the importance of children's influence on family decisions. The strategies used at the time of preparation of meals illustrate the burden of tasks a mother takes on to ensure that her child consumes a particular food. With regard to meal service, very few strategies take into account the appetite of the child. Finally, the variety of strategies deployed at the time of consumption of foods supports the importance of informing parents of the undesirable effect of techniques associated with forcing the child to eat. Avenues for future research are presented.
Looking to the future: a new career education programme
Authors: Ogawa Ikuko , Okada Miyuki
Published: April 2005

A new programme of general family and consumer science for all high school students that can contribute to career education was proposed. The programme had three sessions: ‘single life’, ‘family life’ and ‘retired life’ from the typical three main life stages. Students were challenged to think about their future with regard to real life issues such as housing, location, budgeting time and finances, and family issues. Students were able to consider their future life concretely and specifically from various viewpoints after taking part in this programme. Students also found value in home economics education in developing life skills and knowledge, in considering their actual life and in considering their future life.
Pre‐professionals’ perceptions of home economics in Finland
Authors: Turkki Kaija
Published: April 2005

This article focuses on some new frameworks that have been under discussion in developing the university studies in the field of home economics or family and consumer sciences in Finland. The empirical data were derived from students’ contributions during their university studies in the degree programme for home economics teachers at the Master's level. The aim of this research is to find out students’ present understanding of home economics and its challenges to complete its different functions. All students are at the level of advanced studies (mainly fourth year), and the number of students is 34. The data were collected by essays using SWOT analysis as a method. Students produced a very rich and multisided data that can be analysed in diverse ways and for many purposes. In general, one can say that most students have a very realistic and positive view of their studies. They can analyse them in diverse ways and reveal important qualifications. They are aware of the various challenges which face us in both the present and future societies. Students’ views are critical and they posed several questions outside the course material. They introduced examples from their working experiences and from studies in other departments and education institutes. The empowerment elements were recognized but these should be used more efficiently in attaining further progress in the field. New frameworks and approaches developed in Finland seems to be relevant in the current situations society finds itself.
The Economic Payout Model for Service Guarantees
Authors: Baker Tim , Collier David A.
Published: April 2005

Service guarantees consist of a promise to a customer (marketing), the delivery of a service to the customer (operations), and actions to appease the customer when service failures happen (recovery). A part of recovery involves offering the customer an economic and/or noneconomic payout when things go wrong. When the economic payout is too high or low, the impact on the organization and the customer is usually negative. Therefore, determining the size of the economic payout is of critical strategic and tactical importance in businesses. Yet, no systematic quantitative methods are found in the literature to help managers determine the economic payout for service failures. The current ways an economic payout is determined are management judgment, the consensus of customer focus groups, competitive benchmarking, and the use of simple expected value methods. In this article, we define the Economic Payout Model for Service Guarantees (EPMSG) that provides an optimal service guarantee economic payout under certain conditions. The EPMSG and its objective function considers customer revenue over the short‐ and long‐term, the cost of creating and providing the service, the cost of recovery, the probability of a service failure, and the probability of customer retention as a function of economic payout. A numerical example is provided of how EPMSG works. Customer retention probability distributions are examined assuming normal and gamma distributions. We end the article by describing the theoretical contributions, model limitations, managerial implications, and opportunities for future research.
A Model for Evaluating Organizational Competencies: An Application in the Context of a Quality Management Initiative*
Authors: Escrig‐Tena Ana Belén , Bou‐Llusar Juan Carlos
Published: April 2005

Despite the important contributions made by the Competency‐Based Perspective (CBP) to strategic thought, certain issues on the operational definition of the theoretical concepts that characterize this approach remain unresolved, thus limiting its empirical application. In addressing this issue, the present study puts forward a procedure for measuring the competencies that can be developed in association with a Quality Management (QM) initiative and analyzes the reliability and validity of the resulting scale. This procedure could be transferred to studies that aim to carry out an empirical analysis based on the theoretical position of the CBP.
Decision Support by Interval SMART/SWING—Incorporating Imprecision in the SMART and SWING Methods
Authors: Mustajoki Jyri , Hämäläinen Raimo P. , Salo Ahti
Published: April 2005

Interval judgments are a way of handling preferential and informational imprecision in multicriteria decision analysis (MCDA). In this article, we study the use of intervals in the simple multiattribute rating technique (SMART) and SWING weighting methods. We generalize the methods by allowing the reference attribute to be any attribute, not just the most or the least important one, and by allowing the decision maker to reply with intervals to the weight ratio questions to account for his/her judgmental imprecision. We also study the practical and procedural implications of using imprecision intervals in these methods. These include, for example, how to select the reference attribute to identify as many dominated alternatives as possible. Based on the results of a simulation study, we suggest guidelines for how to carry out the weighting process in practice. Computer support can be used to make the process visual and interactive. We describe the WINPRE software for interval SMART/SWING, preference assessment by imprecise ratio statements (PAIRS), and preference programming. The use of interval SMART/SWING is illustrated by a job selection example.
Using the End‐User Computing Satisfaction (EUCS) Instrument to Measure Satisfaction with a Web Site
Authors: Abdinnour‐Helm Sue F. , Chaparro Barbara S. , Farmer Steven M.
Published: April 2005

The purpose of this study is to revise and revalidate the End‐User Computing Satisfaction (EUCS) instrument to measure satisfaction with a Web site from a usability perspective. This study is especially important given the increased significance of the Web and the uniqueness of the Web as a computing environment. A total of 176 students participated in a lab simulation that involved a usability evaluation of the Lands' End Web site (http://www.landsend.com). Students were asked to complete a set of tasks, record their answers, and then complete the EUCS instrument. Confirmatory factor analysis and invariance analyses were conducted to test the reliability, validity, and generalizability of the revised EUCS. The results show that the EUCS is a valid and robust instrument in the Web environment but that one of the subfactors, timeliness, will need further refinement in the future. Usability practitioners can use the EUCS to measure end‐user satisfaction with a Web site and use the feedback for improving Web‐site design. We describe a case study of an actual usability application that utilized the revised EUCS effectively to support the design of building supply Web sites involving two types of end users, homeowners and contractors. We also propose a typology that researchers can use as a starting point to judge when it is necessary to revalidate an instrument like the EUCS. Finally, we discuss the limitations of our study and present avenues for future research.
Atrial Pacing Should Be Used More Frequently in Sinus Node Disease
Authors: TRIPP IAN G. , ARMSTRONG GUY P. , STEWART JAMES T. , HOOD MARGARET A. , SMITH WARREN M.
Published: April 2005

Background: Single lead atrial (AAI(R)) pacing for sick sinus syndrome provides physiological pacing and is less expensive than a dual chamber system. Compared with ventricular‐based pacing, it maintains the normal cardiac depolarization sequence, is associated with less atrial fibrillation and heart failure, and avoids pacemaker syndrome. We sought whether it is possible to select patients for AAI(R) pacing with a low likelihood of subsequent ventricular pacing, and whether this approach was cost‐effective.

Methods: A retrospective review was conducted of AAI(R) pacemaker implantations. Patients requiring a further procedure for insertion of a ventricular lead (for DDD(R) or VVI(R) pacing) were compared with those who remained atrially paced.

Results: 2.7% (117 of 4,366) of implants were AAI(R), compared with less than 1% overall for New Zealand and Australia. During follow‐up of 3.5 (2.3, 7.7) years, insertion of a ventricular lead was required in 14 (12%), and was more likely in those with pre‐existing PR interval >0.20 seconds (odds ratio 7.8, P = 0.003) or left bundle branch block (LBBB, odds ratio 17, P = 0.037). Right bundle branch block, left anterior fascicular block, or history of paroxysmal atrial fibrillation were not more frequent in the group requiring ventricular pacing, and preimplantation Wenckebach point was not different. The most efficient strategy was initial AAIR implantation in all except those with LBBB or PR interval >0.20 seconds. Compared with routine DDDR implantation, cost was reduced by 20%, with a 1.4% annual incidence of further procedures.

Conclusion: AAIR is the appropriate pacing choice for sick sinus syndrome without LBBB or PR interval >0.20 seconds.