bluuebunny/crossref_metadata_2025_split huggingface dataset:
Exploring the physiological effects of double‐cone coil TMS over the medial frontal cortex on the anterior cingulate cortex: an H215O PET study
Authors: Hayward Gail , Mehta Mitul A. , Harmer Catherine , Spinks Terry J. , Grasby Paul M. , Goodwin Guy M. 
Published: April 2007

AbstractTranscranial magnetic stimulation (TMS) using a double‐cone coil over the medial frontal cortex has the potential to clarify the function of the anterior cingulate cortex (ACC) in cognition, emotion and mood disorders. Following demonstration of disruption of performance on psychological tasks closely linked to cingulate function using this TMS technique, the current study aimed to directly measure the regional distribution of physiological effects of stimulation in the brain with H215O PET. Experiment 1 assessed the effect of increasing numbers of pulse trains of TMS on regional cerebral blood flow (rCBF). Experiment 2 assessed the capacity of medial frontal TMS to modulate brain activity associated with the Stroop task using medial parietal TMS as a control site of stimulation. SPM99 analyses, using the ACC as a region of interest, revealed clusters of increased rCBF during medial frontal TMS in Brodmann area 24 and reduced rCBF in more ventral ACC, the latter occurring in both experiments. In a whole‐brain analysis, striking changes in rCBF were observed distal to the ACC following medial frontal TMS. Although TMS reliably affected Stroop task performance in early trials, there was no interaction between TMS and Stroop condition in rCBF. Our results suggest that medial frontal TMS using the double‐cone coil can affect ACC activity. However, a number of more distal cortical areas were also affected in these experiments. These additional changes may reflect either ‘downstream’ effects of altered cingulate cortex activity or direct effects of the coil.
Severely impaired neuromuscular synaptic transmission causes muscle weakness in the Cacna1a‐mutant mouse rolling Nagoya
Authors: Kaja Simon , Van De Ven Rob C. G. , Van Dijk J. Gert , Verschuuren Jan J. G. M. , Arahata Kiichi , Frants Rune R. , Ferrari Michel D. , Van Den Maagdenberg Arn M. J. M. , Plomp Jaap J. 
Published: April 2007

AbstractThe ataxic mouse rolling Nagoya (RN) carries a missense mutation in the Cacna1a gene, encoding the pore‐forming subunit of neuronal Cav2.1 (P/Q‐type) Ca2+ channels. Besides being the predominant type of Cav channel in the cerebellum, Cav2.1 channels mediate acetylcholine (ACh) release at the peripheral neuromuscular junction (NMJ). Therefore, Cav2.1 dysfunction induced by the RN mutation may disturb ACh release at the NMJ. The dysfunction may resemble the situation in Lambert–Eaton myasthenic syndrome (LEMS), in which autoantibodies target Cav2.1 channels at NMJs, inducing severely reduced ACh release and resulting in muscle weakness. We tested neuromuscular function of RN mice and characterized transmitter release properties at their NMJs in diaphragm, soleus and flexor digitorum brevis muscles. Clinical muscle weakness and fatigue were demonstrated using repetitive nerve‐stimulation electromyography, grip strength testing and an inverted grid hanging test. Muscle contraction experiments showed a compromised safety factor of neuromuscular transmission. In ex vivo electrophysiological experiments we found severely impaired ACh release. Compared to wild‐type, RN NMJs had 50–75% lower nerve stimulation‐evoked transmitter release, explaining the observed muscle weakness. Surprisingly, the reduction in evoked release was accompanied by an ∼ 3‐fold increase in spontaneous ACh release. This synaptic phenotype suggests a complex effect of the RN mutation on different functional Cav2.1 channel parameters, presumably with a positive shift in activation potential as a prevailing feature. Taken together, our studies indicate that the gait abnormality of RN mice is due to a combination of ataxia and muscle weakness and that RN models aspects of the NMJ dysfunction in LEMS.
A quantitative trait locus on chromosome 18 is a critical determinant of excitotoxic cell death susceptibility
Authors: Lorenzana Ariana , Chancer Zackary , Schauwecker P. Elyse 
Published: April 2007

AbstractC57BL/6J (B6) and FVB/NJ (FVB) mice are phenotypically distinct in their susceptibility to seizure‐induced cell death after kainate administration. Previous studies using quantitative trait loci (QTLs) mapping established that the distal region of mouse chromosome 18 contains a gene(s) that is probably responsible for the difference in seizure‐induced cell death susceptibility between two inbred strains, B6 and FVB, that are relatively resistant and susceptible, respectively, to seizure‐induced cell death. The genetic locus has been mapped to a ∼12‐centimorgan region of chromosome 18, designated as seizure‐induced cell death 1 (Sicd1). In order to confirm the Sicd1 QTL, we have developed congenic mouse strains containing the relevant donor segment from the resistant B6 strain on the susceptible FVB background, also referred to as the FVB.B6‐Sicd1 congenic strain. Congenic and FVB littermate controls were tested in a seizure‐induced cell death paradigm. The presence of B6 chromosome 18 alleles on an FVB genetic background conferred protection against seizure‐induced cell death, as compared with FVB littermate controls. To further localize the Sicd1 QTL, new congenic lines carrying overlapping intervals of the B6 segment were created [interval‐specific congenic lines (ISCLs)‐1–4] and assessed for seizure‐induced cell death phenotype. All of the ISCLs exhibited reduced cell death associated with the B6 phenotype, as compared with the parental FVB strain. The most dramatic of these, ISCL‐4, showed a nearly four‐fold reduction in the extent of seizure‐induced cell death. This suggests that ISCL‐4 contains the putative gene(s) of the Sicd1 QTL.
Chronic liver failure in rats impairs glutamatergic synaptic transmission and long‐term potentiation in hippocampus and learning ability
Authors: Monfort Pilar , Erceg Slaven , Piedrafita Blanca , Llansola Marta , Felipo Vicente 
Published: April 2007

AbstractCognitive function is impaired in patients with liver disease by unknown mechanisms. Long‐term potentiation (LTP) in the hippocampus is considered the basis of some forms of learning and memory. The aims of this work were to assess (i) whether chronic liver failure impairs hippocampal LTP; (ii) if this impairment may be due to alterations in glutamatergic neurotransmission, and (iii) if impairment of LTP is associated with reduced learning ability. It is shown that liver failure in Wistar rats induces the following alterations in the hippocampus; (i) alters the phosphorylation of NMDA and AMPA receptors; (ii) reduces the expression of NMDA and AMPA receptors in membranes, (iii) reduces the magnitude of excitatory postsynaptic potentials (EPSPs) induced by activation of NMDA or AMPA receptors, and (iv) impairs NMDA receptor‐dependent LTP. Liver failure also impairs learning of the Morris water maze task. Impairment of glutamatergic synaptic transmission and NMDA receptor‐mediated responses may be involved in the alterations of cognitive function in patients with liver disease.
Event‐related potentials reflect heterogeneity of developmental prosopagnosia
Authors: Minnebusch Denise A. , Suchan Boris , Ramon Meike , Daum Irene 
Published: April 2007

AbstractEvent‐related potential (ERP) studies of developmental prosopagnosia (DP) are rare. Previous ERP investigations have reported smaller N170 amplitude differences between faces and objects in at least three prosopagnosics. The present study is based on a combination of behavioural and electrophysiological assessment of face processing. The aim was to investigate the face‐specifity of the N170 in both healthy subjects and a group of DP individuals (N = 4), using famous and nonfamous faces, caricatures and houses as stimuli. All prosopagnosic subjects showed impairments in recognition of famous faces, memory for faces and learning new faces in behavioural assessment. In healthy subjects the largest effects were found at parieto‐occipital electrode positions (PO7 and PO8), along with a familiarity effect at these electrode positions. Thus, parieto‐occipital areas appear to play an important role in face processing. Three prosopagnosics showed reliable N170 amplitude differences between faces and nonface stimuli, whereas one DP individual showed significantly reduced amplitude differences between faces and nonface objects. The behavioural and electrophysiological data support the idea that DP reflects a heterogeneous impairment and that face processing deficits are not necessarily correlated with a lack of face‐specific N170.
Preservation of visual cortical function following retinal pigment epithelium transplantation in the RCS rat using optical imaging techniques
Authors: Gias Carlos , Jones Myles , Keegan David , Adamson Peter , Greenwood John , Lund Ray , Martindale John , Johnston David , Berwick Jason , Mayhew John , Coffey Peter 
Published: April 2007

AbstractThe aim of this study was to determine the extent of cortical functional preservation following retinal pigment epithelium (RPE) transplantation in the Royal College of Surgeons (RCS) rat using single‐wavelength optical imaging and spectroscopy. The cortical responses to visual stimulation in transplanted rats at 6 months post‐transplantation were compared with those from age‐matched untreated dystrophic and non‐dystrophic rats. Our results show that cortical responses were evoked in non‐dystrophic rats to both luminance changes and pattern stimulation, whereas no response was found in untreated dystrophic animals to any of the visual stimuli tested. In contrast, a cortical response was elicited in most of the transplanted rats to luminance changes and in many of those a response was also evoked to pattern stimulation. Although the transplanted rats did not respond to high spatial frequency information we found evidence of preservation in the cortical processing of luminance changes and low spatial frequency stimulation. Anatomical sections of transplanted rat retinas confirmed the capacity of RPE transplantation to rescue photoreceptors. Good correlation was found between photoreceptor survival and the extent of cortical function preservation determined with optical imaging techniques. This study determined the efficacy of RPE transplantation to preserve visual cortical processing and established optical imaging as a powerful technique for its assessment.
Valproate robustly increases Sp transcription factor‐mediated expression of the dopamine transporter gene within dopamine cells
Authors: Wang Jun , Michelhaugh Sharon K. , Bannon Michael J. 
Published: April 2007

AbstractSeveral lines of evidence suggest that valproate, a drug used in the treatment of mania and bipolar disorders, epilepsies, and addictions, may modulate dopamine transporter (DAT) function, yet the effects of valproate on DAT gene expression have not been directly assessed. Utilizing a human dopaminergic cell line and rat midbrain dopamine (DA) neurons in organotypic culture, we found that valproate increased endogenous DAT gene expression in a concentration‐ and time‐dependent manner. Given previous data demonstrating that members of the specificity protein (Sp) family of transcription factors are strong trans‐activators of DAT gene transcription, we investigated the Sp‐dependence of valproate effects. Valproate‐induced transcription of a DAT reporter construct was significantly attenuated by coexpression of a dominant negative form of Sp, mutation of a Sp‐responsive cis‐element, or expression in a Sp‐null cellular background (SL‐2 cells). Valproate significantly altered Sp protein abundance in both dopaminergic model systems employed. In summary, valproate treatment significantly increased DAT gene expression in a Sp transcription factor‐dependent manner. Some of valproate's therapeutic effects may involve activation of DAT gene expression.
Wheel running following spinal cord injury improves locomotor recovery and stimulates serotonergic fiber growth
Authors: Engesser‐Cesar Christie , Ichiyama Ronaldo M. , Nefas Amber L. , Hill Mary Ann , Edgerton V. Reggie , Cotman Carl W. , Anderson Aileen J. 
Published: April 2007

AbstractExercise, through manual step training, robotic step training or voluntary wheel running, is emerging as a promising therapy after spinal cord injury (SCI). Animal models provide a tool to investigate the mechanisms by which physical activity influences recovery from SCI. In the present study, we extend previous experiments showing improved recovery after SCI with both pre‐ and post‐injury running in a flat‐surface running wheel and investigate mechanisms of recovery. We tested a clinically relevant model using post‐injury wheel running, in which we provided mice with access to wheels either 3 days or 7 days/week. Open field behavior, observed for 15 weeks following moderate T9 contusion injury, showed a significant linear increase in locomotor improvements across groups, sedentary, 3‐day runners and 7‐day runners. Kinematic analysis of treadmill walking revealed that both wheel‐running groups, 3 and 7 days/week, improved stepping ability compared with sedentary controls. Stereological quantification of neuron number in the injured segment of the spinal cord revealed no differences between the groups. However, stereological quantification of serotonin immunostaining using isotropic virtual planes showed increases in serotonin fiber length caudal to the lesion in the running groups. These observations suggest that improvement in function may be related to changes in serotonin fibers immediately caudal to the injury epicenter.
Recombinant human erythropoietin suppresses symptom onset and progression of G93A‐SOD1 mouse model of ALS by preventing motor neuron death and inflammation
Authors: Koh Seong‐Ho , Kim Youngchul , Kim Hyun Young , Won Cho Goang , Kim Kyung Sook , Kim Seung H. 
Published: April 2007

AbstractMultifactorial pathogenic mechanisms, including inflammation, attenuated survival signals and enhanced death signals, are involved in amyotrophic lateral sclerosis (ALS). Erythropoietin (EPO) has recently been highlighted as a cytokine with various potent neuroprotective effects, including reduction of inflammation, enhancement of survival signals and prevention of neuronal cell death. This study was undertaken to evaluate the effect of recombinant human EPO (rhEPO) on ALS model mice. We treated 96 ALS model mice with vehicle only, or 1, 2.5 or 5 iµ of rhEPO/g of mouse once every other week after they were 60 days old. The treatment significantly prolonged symptom onset and life span, preserved more motor neurons, enhanced survival signals, and attenuated inflammatory signals in a dose‐dependent manner. These data suggest that treatment with rhEPO represents a potential therapeutic strategy for ALS.
Structural and functional recovery elicited by combined putrescine and aminoguanidine treatment after aspirative lesion of the fimbria–fornix and overlying cortex in the adult rat
Authors: Muller Christophe , Herberth Heike , Cosquer Brigitte , Kelche Christian , Cassel Jean‐Christophe , Schimchowitsch Sarah 
Published: April 2007

AbstractDamage to the adult CNS often causes permanent deficits. Based on a lesion model of septohippocampal pathway aspiration in the rat, we attempted to promote neuronal cell survival and post‐traumatic recovery by using a pharmalogical treatment combining aminoguanidine and putrescine (AGP). The functional recovery was followed over 15 weeks before morphological analysis. AGP treatment produced a persistent attenuation (∼ 50%) of the lesion‐induced hyperactivity, a reduction (∼ 60%) in the sensorimotor impairments and an improved performance in the water‐maze task which did not, however, rely upon improved memory capabilities. AGP weakened the lesion‐induced decrease in ChAT‐positive neurons in the medial septum and the extent of thalamic retrograde necrosis (by ∼ 30% in each case) and resulted in a partial cholinergic reinnervation of the dentate gyrus. These promising results support the idea that coadministration of putrescine and aminoguanidine might become a potent way to foster structural and functional recovery (or compensation) in the adult mammalian CNS after injury.
Contribution of clinical screening to carrier detection in a large Chinese family with fabry disease due to a novel alpha‐galactosidase A gene deletion
Authors: Ro L.‐S. , Chen C.‐M. , Chang H.‐S. , Lyu R.‐K. , Wu Y.‐R. , Hsu W.‐C. , Lee‐Chen G.‐J. 
Published: April 2007

Diagnosis of heterozygous Fabry patients is difficult because of its variable clinical manifestations and overlapping serum α‐galactosidase A (AGA) activity between carriers and non‐carriers. We tried to facilitate diagnosis of heterozygous Fabry patients by detailed clinical examination. We analyzed clinical presentations, biochemical, electrophysiological and genetic characteristics of 16 patients with Fabry disease in a large Chinese family.Male patients demonstrated significantly higher pain scores, poorer renal function, and higher frequency of hypohidrosis and corpora angiokeratomas than female patients. Interestingly, all the males and females had corneal verticilata by slit lamp examination. However, there was no association of serum AGA activity with renal function or pain symptom scores. The results indicated that detailed ocular and neurological examination might provide an alternative way of detecting heterozygous patients. We also report a novel large deletion spanning across the joint of Alu repetitive elements in introns 1 and 2 with resultant exon 2 deletion in a Chinese family with Fabry disease.
Microfabrics of UHP metamorphic granites in the Dora Maira Massif, western Alps – no evidence of deformation at great depth
Authors: LENZE A. , STÖCKHERT B. 
Published: April 2007

AbstractIn the Dora Maira Massif, western Alps, essentially undeformed ultrahigh‐pressure (UHP) metamorphic granites (Brossasco granite) are embedded in, and locally grade into, granite gneisses or augengneisses and mylonites. In this study, the quartz microfabrics of the undeformed granites are compared against the augengneisses and mylonites in a representative number of samples from several locations. In the undeformed granites, the fine‐grained quartz aggregates that formed from coesite upon decompression are characterized by a foam structure and random crystallographic orientation. In the deformed granites, the quartz microstructures and the crystallographic preferred orientation (CPO) indicate deformation by dislocation creep. Most of the deformation of the granites (if not all) must have happened at a late stage during exhumation, after transformation of coesite to quartz, at greenschist facies conditions in the middle crust. The deformed granites provide no evidence of deformation during subduction, at (U)HP metamorphic conditions, and in the earlier stages of exhumation. The diameter of internally undeformed slices of continental crust subducted to and exhumed from about 100 km can exceed that of the presently exposed Brossasco granite, i.e. it can be on the kilometre scale.
Grenvillian‐aged orogenesis in the Palaeoproterozoic Gascoyne Complex, Western Australia: 1030–950 Ma reworking of the Proterozoic Capricorn Orogen
Authors: SHEPPARD S. , RASMUSSEN B. , MUHLING J. R. , FARRELL T. R. , FLETCHER I. R. 
Published: April 2007

Abstract In situ SHRIMP U–Pb geochronology of monazite and xenotime in pelitic schists from the central Gascoyne Complex, Western Australia, shows that greenschist to amphibolite facies metamorphism occurred between c. 1030 and c. 990 Ma. Monazite from an undeformed rare‐element pegmatite from the same belt gives a 207Pb/206Pb age of c. 950 Ma, suggesting that peak metamorphism and deformation was followed by pegmatite intrusion and coeval granite magmatism. Metamorphism in the central Gascoyne Complex was previously interpreted as Barrovian, largely based on the identification of kyanite in peak metamorphic assemblages, and has been attributed to intense crustal shortening and substantial tectonic thickening during Palaeoproterozoic continent–continent collision. However, the stable Al2SiO5 polymorph has been identified in this study as andalusite rather than kyanite, and the prograde assemblages of staurolite–garnet–andalusite–biotite–muscovite–quartz indicate temperatures of 500–550 °C and pressures of 3–4 kbar. These data show that the Palaeoproterozoic Gascoyne Complex underwent an episode of Grenvillian‐aged intracontinental reworking concentrated in a NW–SE striking corridor, during the Edmundian Orogeny. Until now, the Edmundian Orogeny was thought to have involved only reactivation of structures in the Gascoyne Complex, along with deformation and very low‐ to low‐grade metamorphism of Mesoproterozoic cover rocks some time between 1070 and 755 Ma. However, we suggest that it involved regional amphibolite facies metamorphism and deformation, granite magmatism and pegmatite intrusion between c. 1030 and c. 950 Ma. Therefore, the Capricorn Orogen experienced a major phase of tectonic reworking c. 600 Myr later than previously recognized. Our results emphasize the importance of in situ geochronology integrated with petrological studies in order to link the metamorphic history of a terrane with causally related tectonic events.
Growth and Major Nutrient Concentrations in Brassica campestris Supplied with Different NH4+/NO3− Ratios
Authors: Zhang Fu‐Cang , Kang Shao‐Zhong , Li Fu‐Sheng , Zhang Jian‐Hua 
Published: April 2007

AbstractIn the present study, we investigated whether growth and main nutrient ion concentrations of cabbage (Brassica campestris L.) could be increased when plants were subjected to different NH4+/NO3− ratios. Cabbage seedlings were grown in a greenhouse in nutrient solutions with five NH4+/NO3− ratios (1:0; 0.75:0.25; 0.5:0.5; 0.25:0.75; and 0:1). The results showed that cabbage growth was reduced by 87% when the proportion of NH4+‐N in the nutrient solution was more than 75% compared with a ratio NH4+/NO3− of 0.5:0.5 35 d after transplanting, suggesting a possible toxicity due to the accumulation of a large amount of free ammonia in the leaves. When the NH4+/NO3− ratio was 0.5:0.5, fresh seedling weight, root length, and H2PO4− (P), K+, Ca2+, and Mg2+ concentrations were all higher than those in plants grown under other NH4+/NO3− ratios. The nitrate concentration in the leaves was the lowest in plants grown at 0.5: 0.5 NH4+/NO3−. The present results indicate that an appropriate NH4+/NO3− ratio improves the absorption of other nutrients and maintains a suitable proportion of N assimilation and storage that should benefit plant growth and the quality of cabbage as a vegetable.
Sap Flow of Populus euphratica in a Desert Riparian Forest in an Extreme Arid Region During the Growing Season
Authors: Si Jian‐Hua , Feng Qi , Zhang Xiao‐You , Chang Zong‐Qiang , Su Yong‐Hong , Xi Hai‐Yang 
Published: April 2007

AbstractIn the present study, the heat pulse technique was applied to investigate the stem sap flow of Populus euphratica in a desert riparian forest in an extreme arid region from April to October 2003 and from May to October 2004. The experimental sites were in Qidaoqiao (101°10′ E, 41°59′ N) and Bayantaolai farm (101°14′ E, 42°01′ N) in Ejina county, in the low reaches of the Heihe River, China. The results indicated that the diurnal change in the velocity of sap flow showed minor fluctuations. At night, the rising of sap flow could be observed in the main tree species because of root pressure. During the growing season, the maximum average velocity was observed in July, followed by August, and the same velocity was observed in September and May; the minimum velocity was observed in October. The transpiration from June to August during the growing season accounted for approximately 70% of the annual total transpiration. The sap flow velocity of P. euphratica trees of different ages could be arranged in the order: 15 yr > 25 yr > 50 yr. Sap flow velocity was closely related to changes in micrometeorological factors, with average sap flow velocity showing a significant linear correlation with net radiation, air temperature and relative humidity.