bluuebunny/crossref_metadata_2025_split huggingface dataset:
Usefulness of carotid parameters measured by ultrasonography as a marker of atherothrombotic infarction and lacunar infarction in high‐risk elderly people
Authors: Watanabe Kentaro , Suzuki Tatsuya , Nakano Hiroshi , Oba Kenzo 
Published: June 2006

Aim:  Many studies have reported that carotid parameters measured by ultrasonography are predictors for cerebral infarction. The aim of this study was to investigate by a cross‐sectional study whether those carotid parameters are markers for atherothrombotic infarction (AI) and lacunar infarction (LI) in elderly people having cardiovascular risk factors.Methods:  We studied 314 patients aged 65 years or older who had controlled cardiovascular diseases and assessed carotid arteries by ultrasonography. The subjects were categorized into control, AI and LI groups. Clinical characteristics (biochemical analysis, body mass index, systolic/diastolic blood pressure, smoking habits, hypertension, diabetes mellitus and statin therapy) and carotid parameters (maximum intima‐media thickness [Max‐IMT], plaque score [PLQ‐S] and maximum pulsatility index [Max‐PI]) were compared among the three groups.Results:  PLQ‐S, Max‐PI, frequency of PLQ‐S ≥ 10 mm and frequency of Max‐PI ≥ 2.0 were significantly higher in the AI group than in the control group. There were no significant differences between the control and LI groups concerning carotid parameters. Multivariate logistic regression analysis showed that there were significant correlations between AI and PLQ‐S ≥ 10 mm (odds ratio 2.980; P = 0.011), AI and Max‐PI ≥ 2.0 (odds ratio 2.458; P = 0.038), but there were no significant correlations between those carotid parameters and LI.Conclusions:  This study suggests that in high‐risk elderly people, PLQ‐S and PI are better markers for AI than IMT, but those carotid parameters do not correlate with LI.
Biochemical and electrophysiological changes of substantia nigra pars reticulata driven by subthalamic stimulation in patients with Parkinson's disease
Authors: Galati Salvatore , Mazzone Paolo , Fedele Ernesto , Pisani Antonio , Peppe Antonella , Pierantozzi Mariangela , Brusa Livia , Tropepi Domenicantonio , Moschella Vincenzo , Raiteri Maurizio , Stanzione Paolo , Bernardi Giorgio , Stefani Alessandro 
Published: June 2006

AbstractTo understand the events underlying the clinical efficacy of deep brain stimulation (DBS) of the subthalamic nucleus (STN), electrophysiological recordings and microdialysis evaluations were carried out in the substantia nigra pars reticulata (SNr), one of the two basal ganglia (BG) nuclei targeted by STN output, in patients with Parkinson's disease (PD). Clinically effective STN‐DBS caused a significant increase of the SNr firing rate. The poststimulus histogram (PSTH) showed an excitation peak at 1.92–3.85 ms after the STN stimulus. The spontaneous discharge of SNr neurons was driven at the frequency of the stimulation (130 Hz), as shown in the autocorrelograms (AutoCrl). The fast Fourier transform (FFT) analysis showed a peak at 130 Hz, and a less pronounced second one at 260 Hz. Accordingly, in the distribution of the interspike intervals (ISIs), the mode was earlier, and skewness more asymmetric. Biochemically, the increased excitatory driving from the STN was reflected by a clear‐cut increase in cyclic guanosine 3',5'‐monophosphate (cGMP) levels in the SNr. These results indicate that the beneficial effect of DBS in PD patients is paralleled with a stimulus‐synchronized activation of the STN target, SNr. Our findings suggest that, during STN‐DBS, a critical change towards a high‐frequency oscillatory discharge occurs.
Testosterone and photoperiod interact to affect spatial learning and memory in adult male white‐footed mice (Peromyscus leucopus)
Authors: Pyter Leah M. , Trainor Brian C. , Nelson Randy J. 
Published: June 2006

AbstractGonadal hormones affect spatial learning and memory in mammals and circulating gonadal hormone concentrations fluctuate by season. Most nontropical rodents are spring/summer breeders and males display higher testosterone concentrations during the breeding season compared with the nonbreeding season (fall/winter). Seasonal patterns of testosterone concentration (as well as many other seasonal modifications of physiology, morphology, and behaviour) are induced by manipulation of photoperiod (day length; i.e. short or long days) in the laboratory. Coincident with reducing testosterone concentration, short days also impair spatial learning and memory performance in male white‐footed mice (Peromyscus leucopus) compared with long days. We hypothesized that short‐day‐induced reduction of testosterone concentrations inhibits spatial learning and memory performance compared with long days. Adult male white‐footed mice were maintained in long (16 h light/day) or short (8 h light/day) days for 14 weeks following sham‐castration, castration plus saline implant, or castration plus testosterone implant treatment. Spatial learning and memory was assessed using a water maze, and photoperiod‐evoked changes in gene expression of sex steroid receptors within the hippocampus were also examined. Castrated, short‐day mice with testosterone replacement displayed enhanced water maze performance compared with other short‐day mice, but no differences among testosterone treatments were observed in long‐day mice. Photoperiod did not affect hippocampal androgen, oestrogen α, or oestrogen β receptor gene expression. These results suggest that photoperiod modulates the effects of testosterone on spatial learning performance by mechanisms indirect of the hippocampus.
Selective prefrontal serotonin depletion impairs acquisition of a detour‐reaching task
Authors: Walker S.C. , Mikheenko Y.P. , Argyle L.D. , Robbins T.W. , Roberts A.C. 
Published: June 2006

AbstractWe have recently shown that serotonin in the primate orbitofrontal cortex (OFC) contributes to the flexible control of behaviour. 5,7‐dihydroxytryptamine‐induced 5‐HT depletions of OFC impair performance on a serial reversal discrimination task [Clarke et al. (2004)Science, 304, 878–880]. The deficit is characterized by perseverative responding to the previously rewarded stimulus, a deficit similar to that seen following lesions of the intrinsic neurones of the OFC [Dias et al. (1996)Nature, 380, 69–72]. The effect is neurochemically selective as dopaminergic lesions of the OFC, induced by 6‐hydroxydopamine, have no effect [Clarke et al. (2006)Cerebral Cortex]. In order to test for the generality of the effect of serotonin on orbitofrontal processing and, in particular, its effects on flexible behaviour, the present study investigated the effects of serotonin depletions of OFC on performance of another task dependent upon an intact OFC, the detour‐reaching task [Wallis et al. (2001)European Journal of Neuroscience, 13, 1797–1808]. Successful performance of this task requires inhibition of the animal's prepotent response tendency to reach directly along its line of sight to the reward. Compared with sham‐operated controls, we found that lesioned monkeys made significantly more barrier reaches directly along their line of sight to the visible reward during task acquisition. This finding provides further support for the role of prefrontal serotonin in inhibitory control processes specifically in tasks sensitive to OFC dysfunction.
Early midline interactions are important in mouse optic chiasm formation but are not critical in man: a significant distinction between man and mouse
Authors: Neveu Magella M. , Holder Graham E. , Ragge Nicola K. , Sloper John J. , Collin J. Richard O. , Jeffery Glen 
Published: June 2006

AbstractThe optic chiasm is one of the most popular models for studying axon guidance. Here axons make a key binary decision either to cross the midline to innervate the contralateral hemisphere or to remain uncrossed. In rodents, midline interactions between axons from the two eyes are critical for normal development, as early removal of one eye systematically disrupts hemispheric projections from the remaining eye, increasing the crossed projection at the expense of the uncrossed. This is similar to the abnormal decussation pattern seen in albinos. This pattern is markedly different in marsupials where early eye removal has no impact on projections from the remaining eye. These differences are related to the location of the uncrossed projection through the chiasm. In rodents these axons approach the midline whereas in marsupials they remain segregated laterally. We provide anatomical evidence in man suggesting that, unlike in rodents, uncrossed axons are confined laterally and do not mix in each hemi‐chiasm, which is a pattern similar to that found in marsupials. Further, we demonstrate electrophysiologically, using visual cortical evoked potentials, that the failure of one eye to develop in man has no impact on the hemispheric projections from the remaining eye. These data demonstrate that the mechanisms regulating chiasmal development in man differ from those in rodents but may be similar to those in marsupials. We suggest that mouse models of the organization and development of the optic chiasm are not common to placental mammals in general.
An endogenous inhibitor of calcium/calmodulin‐dependent kinase II is up‐regulated during consolidation of fear memory
Authors: Lepicard Eve M. , Mizuno Keiko , Antunes‐Martins Ana , Von Hertzen Laura S. J. , Giese K. Peter 
Published: June 2006

AbstractCaMKIINα and CaMKIINβ are endogenous inhibitors of the abundant synaptic protein, calcium/calmodulin‐dependent protein kinase II (CaMKII). CaMKII exerts a prominent function in memory formation and the endogenous inhibitors might be important regulators of CaMKII activity during this process. Here we investigated whether or not CaMKIINα and CaMKIINβ gene expressions are regulated in the mouse hippocampus and amygdala after background contextual fear conditioning. Quantitative real‐time PCR revealed that the hippocampal expression of CaMKIINα mRNA was up‐regulated 30 and 60 min after conditioning. In contrast, CaMKIINβ mRNA expression did not change. The up‐regulation of CaMKIINα expression was specific for the fear memory because the context alone and a shock control did not induce any variation of transcription level. Quantification of in situ hybridization signals showed that CaMKIINα expression increased in hippocampal area CA1, in the dentate gyrus (DG) and in the lateral amygdala (LA) 30 min after training. Our findings show an up‐regulation in the expression of the endogenous inhibitor gene CaMKIINα during consolidation of fear memory. The early onset and the amplitude of the up‐regulation are similar to those of immediate‐early genes. Taken together, our results suggest that the CaMKIINα inhibitor has a physiological role in controlling CaMKII activity from an early stage of memory consolidation.
Retinocollicular synaptogenesis and synaptic transmission during formation of the visual map in the superior colliculus of the wallaby (Macropus eugenii)
Authors: Flett D. L. , Lim C. H. , Ho S. M. , Mark R. F. , Marotte L. R. 
Published: June 2006

AbstractSpontaneous retinal activity has been implicated in the development of the topographic map in the superior colliculus (SC) but a direct demonstration that it reaches the colliculus is lacking. Here we investigate when the retinocollicular projection is capable of transmitting information from the retina in a marsupial mammal, the wallaby (Macropus eugenii). The projection develops postnatally, allowing in vivo analysis throughout development. Quantification of retinocollicular synaptogenesis has been combined with electrophysiology of the development and characteristics of retinocollicular transmission, including in vivo and in vitro recording in the same animals. Prior to postnatal day (P) 12–14 in vitro recording detected only presynaptic activity in retinal axons in the colliculus, in response to stimulation of the optic nerve. Postsynaptic responses, comprising both N‐methyl‐d‐aspartate (NMDA) and non‐NMDA responses, were first detected in vitro at P12–14 and retinal synapses were identified. In contrast, postsynaptic responses to optic nerve stimulation could not be detected in vivo until P39, around the time that retinal axons begin arborizing. Around this age density and numbers of total synapses began increasing in the retinorecipient layers of the colliculus. By P55–64, the numbers of retinal synapses had increased significantly and density and numbers of retinal and total synapses continued to increase up to P94–99. During this time the map is undergoing refinement and degenerating axons and synapses were present. The discrepancy between in vitro and in vivo onset of functional connections raises the question of when retinal activity reaches collicular cells in the intact, unanaesthetized animal and this will require investigation.
Immunocytochemical evidence for the existence of substance P receptor (NK1) in serotonin neurons of rat and mouse dorsal raphe nucleus
Authors: Lacoste Baptiste , Riad Mustapha , Descarries Laurent 
Published: June 2006

AbstractIn addition to its neurotransmitter/modulator role in pain perception, substance P (SP) is involved in a regulation of mood, as antagonists of its neurokinin‐1 receptor (NK1r) have been found to have antidepressant‐like effects in humans. In rodents, treatment with NK1r antagonists has been shown to increase the firing of dorsal raphe nucleus (DRN) serotonin (5‐hydroxytryptamine, 5‐HT) neurons and to induce a desensitization of their 5‐HT1A autoreceptors, suggesting local interactions between the SP and 5‐HT systems. To search for the presence of NK1r on 5‐HT neurons of the DRN, we used light and electron microscopic immunocytochemistry, as well as confocal microscopy, after single‐ and double‐labelling of NK1r and of the biosynthetic enzyme of 5‐HT, tryptophan hydroxylase (TpOH). A significant number of 5‐HT (TpOH‐positive) cell bodies and dendrites endowed with NK1r were thus demonstrated in the caudal part of rat and mouse DRN. As visualized by electron microscopy after gold immunolabelling, NK1r was mostly cytoplasmic in 5‐HT neurons, while predominating on the plasma membrane in the case of TpOH‐negative dendrites. The proportion of NK1r observed on the plasma membrane of 5‐HT neurons was, however, slightly higher in mouse than rat. Thus, in both rat and mouse DRN, a subpopulation of 5‐HT neurons is endowed with NK1r receptors and may be directly involved in the antidepressant‐like effects of NK1r antagonists. These 5‐HT neurons represent a new element in the neuronal circuitry currently proposed to account for the role of SP in mood regulation.
Status epilepticus differentially alters AMPA and kainate receptor subunit expression in mature and immature dentate granule neurons
Authors: Porter Brenda E. , Cui Xiao‐Nan , Brooks‐Kayal Amy R. 
Published: June 2006

AbstractThere is an increase in the birth of dentate granule neurons after status epilepticus (SE) and there are concurrent alterations in neurotransmitter receptor expression that may contribute to the development of spontaneous seizures. To determine whether newborn and/or mature dentate granule neurons have altered neurotransmitter receptor expression after SE, we dissected individual immature, PSA‐NCAM‐expressing, or mature, NeuN‐expressing, dentate granule neurons 2 weeks after lithium–pilocarpine‐induced SE in postnatal day 20 rats. Amplified single‐cell RNA was used to probe reverse Northern blots containing α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazole propionic acid (AMPA) and kainate neurotransmitter receptor subunits. Two weeks after lithium–pilocarpine‐induced SE there were increases in AMPA GluR2 and kainate KA2 subunit mRNA and decreases in AMPA GluR3 and kainate GluR6 receptor subunit mRNA levels in mature dentate granule neurons. In contrast, only the kainate GluR6 subunit expression was reduced in immature dentate granule neurons after SE. Alterations in transcription of excitatory amino acid receptor subunits after SE occur primarily in the mature population of dentate granule neurons. Our findings suggest that neurotransmitter receptor gene expression is altered differently in immature and mature dentate granule neurons following SE, and may result in differential contributions of these two groups of dentate granule neurons to the subsequent development of epilepsy.
Factors affecting willow leaf beetles (Phratora vulgatissima) when selecting overwintering sites
Authors: Björkman Christer , Eklund Karin 
Published: June 2006

Abstract

Leaf beetles are major pests in willow plantations used as short‐rotation coppice for biomass production. The beetles overwinter mainly outside the plantations. An understanding of the factors affecting adult leaf beetles seeking overwintering sites may provide information that could be valuable when developing methods to control the beetles.
We conducted a field experiment in a willow plantation with a high abundance of the leaf beetle, Phratora vulgatissima. We positioned overwintering constructions (OWCs) made out of bundles of reed (Phragmites australis) outside the plantation.
Leaf beetles preferred (i) to fly towards silhouettes; (ii) OWCs positioned 1.5 m above the ground compared with ones 0.5 m above the ground; (iii) OWCs orientated vertically compared with OWCs orientated horizontally; and (iv) reeds of a diameter of approximately 5 mm.
Leaf beetle size was not correlated with reed diameter.
It is concluded that the leaf beetle P. vulgatissima selects an overwintering site based on factors at both larger and smaller scales. The possibilities for using OWCs made of reed bundles as tools to monitor and control are discussed.
Models for spring migration of two aphid species Sitobion avenae (F.) and Rhopalosiphum padi (L.) infesting cereals in areas where they are entirely holocyclic
Authors: Hansen Lars Monrad 
Published: June 2006

Abstract1 Cereals can be attacked severely by the grain aphid, Sitobion avenae (F.), and the bird cherry‐oat aphid, Rhopalosiphum padi (L.). The time of migration from winter hosts in spring is important regarding input to decision support systems concerning insecticide treatment of aphids.2 The present study aimed to construct two separate migration models, which could be used immediately for advisors and farmers but also be part of a decision support system for the chemical control of aphids in winter wheat and spring barley.3 Winter wheat (Triticum sativum Lam.) and spring barley (Hordeum vulgare L.) fields were monitored from 1991–2005 for the occurrence of grain aphids and bird cherry‐oat aphids, and the data were used to construct migration models.4 The models were constructed based on all 9 years data and subsequently validated by using all 9 years data, excluding 1 year at a time.5 The migration model for the grain aphid producing the best forecast was obtained with migration date M (number of days from 1 June), degree‐days (DD) of April (Ta) and DD of May (Tm), with the model being M= 265.0 − 10.2 loge(Ta) − 35.1 loge(Tm).6 The migration model for the bird cherry‐oat aphid producing the best forecast was obtained with migration date M (number of days from 15 May), DD of April (Ta) and DD from 1–15 May (Tm1), with the model being M= 294.4 − 34.7 loge(Ta) − 22.5 loge(Tm1).7 The models only worked well in areas where the grain aphid and the bird cherry‐oat aphid are entirely holocyclic.
Distribution and population genetic structure of the Mediterranean pine shoot beetle Tomicus destruens in the Iberian Peninsula and Southern France
Authors: Vasconcelos Teresa , Horn Agnès , Lieutier François , Branco Manuela , Kerdelhué Carole 
Published: June 2006

Abstract1 The Mediterranean pine shoot beetle Tomicus destruens has long been indistinguishable from its congeneric Tomicus piniperda. Both species attack pines, and can be found in sympatry. The geographical distribution of T. destruens is still unclear in most of the Mediterranean Basin.2 We aimed to describe the geographical distribution and zones of sympatry of both species in the Iberian Peninsula and France, and to study the molecular phylogeographical pattern of T. destruens.3 Tomicus spp. adults were sampled in Portugal, Spain and France, and a portion of the mitochondrial genes COI and COII was sequenced for 84 individuals. Sequences were aligned to a data set previously obtained from French localities.4 Tomicus destruens was found in all populations, except for one locality in Portugal and in the Landes (France). It was in sympatry with T. piniperda in two locations on Pinus pinaster and one location on Pinus radiata.5 Within‐population genetic diversity was high, but we found a significant pattern of spatial distribution of genetic variation, as well as a significant effect of the host tree.6 The data suggest the existence of two glacial refugia, from which T. destruens recolonized its current range. One refugium was located in Portugal where the beetle probably evolved on P. pinaster. The corresponding haplotypes show a West–East frequency gradient. The other refugium was probably in the eastern range, where the beetles evolved on Pinus halepensis and P. pinea. The corresponding haplotypes show an East–West frequency gradient.
Phenology of Eucalyptus weevil, Gonipterus scutellatus Gyllenhal (Coleoptera: Curculionidae), and chrysomelid beetles in Eucalyptus globulus plantations in south‐western Australia
Authors: Loch A. D. 
Published: June 2006

Abstract1 In south‐western Australia, Eucalyptus globulus plantations are defoliated by a complex of beetle species, yet only scant information exists on these species under such climatic conditions. To improve management of these defoliating beetles in the region, canopy fogging and shoot clipping were conducted in plantations between 1999 and 2002 to identify and document the phenology of the beetle species present.2 Eucalyptus weevil, Gonipterus scutellatus, was the most common and destructive defoliating beetle. Gonipterus scutellatus undergoes one principal generation each year with a lesser second generation or cohort in some seasons, which contrasts greatly with reports of two to four annual generations for the species in other regions. This limited reproduction by G. scutellatus may be due to the limited availability from summer onwards of new flushing foliage, which is essential for feeding and oviposition.3 Several species of chrysomelid beetles were collected in plantations, but these were present in much lower numbers than G. scutellatus and were only a minor concern. However, some species, such as Chrysophtharta variicollis, appear to be capable of developing short‐lived outbreaks.4 A diverse suite of natural enemies was fogged from plantations but they were significantly less abundant than defoliating beetles and are not likely to provide significant control of beetles.5 In terms of managing these defoliating beetles, monitoring and control should focus on G. scutellatus, and be conducted during spring when most damage occurs.
The role of chronic hypoxia in the development of neurocognitive abnormalities in preterm infants with bronchopulmonary dysplasia
Authors: Raman Lakshmi , Georgieff Michael K. , Rao Raghavendra 
Published: June 2006

Abstract Bronchopulmonary dysplasia is the most common pulmonary morbidity in preterm infants and is associated with chronic hypoxia. Animal studies have demonstrated structural, neurochemical and functional alterations due to chronic hypoxia in the developing brain. Long‐term impairments in visual‐motor, gross and fine motor, articulation, reading, mathematics, spatial memory and attention skills are prevalent in survivors of bronchopulmonary dysplasia, and impairments appear to correlate with the severity of hypoxia. However, due to the simultaneous occurrence of multiple neurodevelopmental risk factors, a primary or potentiating role for chronic hypoxia in these impairments has yet to be conclusively established.