bluuebunny/crossref_metadata_2025_split huggingface dataset:
A method for the direct electrical stimulation of the auditory system in deaf subjects: A functional magnetic resonance imaging study
Authors: Alwatban Adnan Z. , Ludman Catherine N. , Mason Steve M. , O'Donoghue Gerard M. , Peters Andrew M. , Morris Peter G. 
Published: October 2002

AbstractPurposeTo develop a safe functional magnetic resonance imaging (fMRI) procedure for auditory assessment of deaf subjects.Materials and MethodsA gold‐plated tungsten electrode has been developed which has zero magnetic susceptibility. Used with carbon leads and a carbon reference pad, it enables safe, distortion‐free fMRI studies of deaf subjects following direct electrical stimulation of the acoustic nerve. Minor pickup of the radio frequency (RF) pulses by the electrode assembly is difficult to eliminate, and a SPARSE acquisition sequence is used to avoid any effects of unintentional auditory nerve stimulation.ResultsThe procedure is demonstrated in a deaf volunteer. Activation is observed in the contralateral but not the ipsilateral primary auditory cortex. This is in sharp contrast to studies of auditory processing in hearing subjects, but consistent with the small number of previous positron emission tomography (PET) and MR studies on adult deaf subjects.ConclusionThe fMRI procedure is able to demonstrate whether the auditory pathway is fully intact, and may provide a useful method for preoperative assessment of candidates for cochlear implantation. J. Magn. Reson. Imaging 2002;16:6–12. © 2002 Wiley‐Liss, Inc.
Passive catheter tracking using MRI: Comparison of conventional and magnetization‐prepared FLASH
Authors: Green Jordin D. , Omary Reed A. , Finn J. Paul , Tang Richard , Li Yongzhong , Carr James , Li Debiao 
Published: October 2002

AbstractPurposeTo compare a magnetization‐prepared gradient‐echo (GRE) sequence with a conventional GRE sequence for visualizing contrast agent‐filled catheters.Materials and MethodsPassive visualization of endovascular catheters using MRI was compared between two imaging sequences: 1) inversion recovery (IR)‐fast low angle shot (FLASH), and 2) conventional FLASH. Two‐dimensional projection images of the catheters filled with 4% diluted contrast agent in a phantom and the aorta of swine were obtained with each sequence with a temporal resolution of two frames per second. We compared background suppression and catheter visibility using the catheter‐to‐background signal ratio and the ratings of two radiologists.ResultsIn the phantom, IR‐FLASH allowed for a 200% increase in catheter‐to‐background ratio (p < 0.01) and improved depiction of catheters over conventional FLASH. In swine, the IR‐FLASH images showed a statistically significant improvement of 80% (p < 0.001) over conventional FLASH in all comparisons of the catheter‐to‐background signal ratio, and an improvement of 160% (p < 0.05) in comparison with the radiologists' observations.ConclusionThis study shows that IR‐FLASH is a better technique for passive tracking of contrast agent‐filled catheters than conventional FLASH. J. Magn. Reson. Imaging 2002;16:104–109. © 2002 Wiley‐Liss, Inc.
Optimal post‐contrast timing of breast MR image acquisition for architectural feature analysis
Authors: Nunes Linda White , Englander Sarah A. , Charafeddine Riad , Schnall Mitchell D. 
Published: October 2002

AbstractPurposeTo define a post‐contrast imaging time span during which diagnostic accuracy of breast magnetic resonance (MR) architectural feature analysis is maintained.Materials and MethodsSeventy‐five patients with mammographically‐visible or palpable findings underwent MR examination. Three sequential post‐contrast, fat‐saturated, three‐dimensional gradient‐echo imaging runs were acquired spanning 0–90, 90–180, and 180–270 seconds after contrast injection. Five readers independently predicted the malignant potential of the MR abnormalities.ResultsReceiver‐operator characteristics (ROC) curves were our primary measure of diagnostic accuracy. The accuracy of four readers was unchanged over the three post‐contrast runs. One reader was slightly more accurate using the second and third runs than using the first.ConclusionFor most readers, a single post‐contrast run performed at any point during the first four minutes and 30 seconds following injection should yield an equivalent diagnostic accuracy. If any time period is less optimal, it is that of our first run, performed between 0–90 seconds after contrast injection. J. Magn. Reson. Imaging 2002;16:42–50. © 2002 Wiley‐Liss, Inc.
TLM models of bending transients and their application to the deformation of thin walled ceramic shapes
Authors: Newton H. R. , Pulko S. H. , Wilkinson A. J. 
Published: October 2002

AbstractA transmission line matrix model of viscous bending under gravity is devised. This is initially extended to a two‐component, parallel, dashpot‐spring model corresponding to a Kelvin solid, and then to a three‐component model comprising an initial elastic deflection followed by a slow viscoelastic deformation. This three‐component model is used to predict the deformation of thin walled ceramic shapes during firing. Predicted deformations and those observed in fired ceramic pieces are compared for three types of ceramic shape; bars supported as cantilevers, vertical hoops and three‐dimensional ‘mushroom’ shaped shells. Copyright © 2002 John Wiley & Sons, Ltd.
γ‐aminobutyric acid transporter (BGT‐1) expressed in human astrocytoma U373 MG cells: Pharmacological and molecular characterization and phorbol ester‐induced inhibition
Authors: Ruiz‐Tachiquín M.‐E. , Sánchez‐Lemus E. , Soria‐Jasso L.‐E. , Arias‐Montaño J.‐A. , Ortega A. 
Published: October 2002

AbstractThe properties of a transport system specific for γ‐aminobutyric acid (GABA) expressed in human U373 MG astrocytoma cells were examined. The uptake of [3H]GABA was dependent on both extracellular Na+ and Cl– ions and was inhibited by (±)‐nipecotic acid, guvacine, and β‐alanine, with a pharmacological profile corresponding to that reported for the human homologue of the GABA/betaine transporter (BGT‐1). Accordingly, [3H]GABA uptake was also inhibited by betaine, and reverse transcriptase‐polymerase chain reaction (RT‐PCR) analysis of total RNA from U373 MG cells with specific BGT‐1 primers resulted in the amplification of a 440 bp fragment that was further characterized by restriction analysis and sequencing. In addition, Western blot analysis with anti‐BGT‐1 antiserum revealed the presence of a characteristic 60 kDa band. The primary structure of the human BGT‐1 protein predicts two putative phosphorylation sites for the Ca2+/diacylglicerol‐dependent protein kinase (PKC), and treatment of U373 MG cells with the PKC activator phorbol 12‐myristate‐13‐acetate (TPA) led to a concentration‐ and time‐dependent decrease in [3H]GABA uptake. The maximal effect was detected at 2 hr of incubation, to disappear after 4 hr. TPA‐induced reduction in [3H]GABA uptake was reversed by preincubation with staurosporine. Taken together, these results indicate that U373 MG cells express a GABA transporter of the BGT‐1 subtype whose function is regulated by phosphorylation events through PKC. © 2002 Wiley‐Liss, Inc.
Expression of inducible nitric oxide synthase and cyclooxygenase‐2 after excitotoxic damage to the immature rat brain
Authors: Acarin Laia , Peluffo Hugo , González Berta , Castellano Bernardo 
Published: October 2002

AbstractIt is well established that after adult brain damage the enzymes cyclooxygenase‐2 (COX‐2) and inducible nitric oxide synthase (iNOS) play an important role in the inflammatory processes and oxidative stress, which are considered to be the leading factors contributing to delayed cell death. The contribution of these enzymes to postnatal brain damage, however, is poorly understood. In our study, excitotoxic lesions were induced by the injection of N‐methyl‐D‐aspartate in the cortex of postnatal day 9 rats. After different survival times ranging from 4 hr to 7 days post‐lesion, brain sections were processed for the immunocytochemical demonstration of COX‐2 and iNOS and double labeling with neuronal, glial and neutrophil markers. First and maximal de novo induction of iNOS and COX‐2 expression was found at 10 hr post‐lesion. Expression of both enzymes started to diminish at 24 hr, reaching basal levels at day 3. iNOS‐expressing cells were mainly identified as infiltrated neutrophils as well as highly ramified protoplasmic astrocytes closely associated with blood vessels. Moreover, scattered iNOS‐positive neurons were found at the lesion borders. In contrast, COX‐2 was mainly observed in reactive microglial cells and neuronal cells. COX‐2‐positive neurons were found within the degenerating area at 10 hr and at the borders of the lesion later on. This study shows that maximal iNOS and COX‐2 expression precedes the period of massive neuronal death observed at 24 hr post‐lesion, and may therefore contribute to the evolution of the inflammatory response and the neurodegenerative process after an excitotoxic lesion to the postnatal brain. © 2002 Wiley‐Liss, Inc.
GeneChip® analysis shows altered mRNA expression of transcripts of neurotransmitter and signal transduction pathways in the cerebral cortex of portacaval shunted rats
Authors: Song Guoqing , Dhodda Vinay K. , Blei Andres T. , Dempsey Robert J. , Rao Vemuganti L. Raghavendra 
Published: October 2002

AbstractIdentifying the gene expression changes induced by hepatic encephalopathy (HE) leads to a better understanding of the molecular mechanisms of HE‐induced neurological dysfunction. Using GeneChip® and real‐time PCR, the present study evaluated the gene expression profile of rat cerebral cortex at 4 weeks after portacaval shunting. Among 1,263 transcripts represented on the chip, mRNA levels of 31 transcripts were altered (greater than twofold; 16 increased and 15 decreased) in the portacaval shunted (PCS) rat compared to sham control. Changes observed by GeneChip® analysis were confirmed for 20 transcripts (8 increased, 7 decreased, and 5 unchanged in PCS rat brain) by real‐time PCR. Neurotransmitter receptors, transporters, and members of the second messenger signal transduction are the major groups of genes altered in PCS rat brain. Of importance was that the increased heme oxygenase‐1 and decreased Cu,Zn‐superoxide dismutase expression observed raise the possibility of oxidative stress playing a pathogenic role in chronic HE. © 2002 Wiley‐Liss, Inc.
Immunoglobulin Fcγ receptor promotes immunoglobulin uptake, immunoglobulin‐mediated calcium increase, and neurotransmitter release in motor neurons
Authors: Mohamed Habib A. , Mosier Dennis R. , Zou Ling L. , Siklós László , Alexianu Maria E. , Engelhardt Jozsef I. , Beers David R. , Le Wei‐dong , Appel Stanley H. 
Published: October 2002

AbstractReceptors for the Fc portion of immunoglobulin G (IgG; FcγRs) facilitate IgG uptake by effector cells as well as cellular responses initiated by IgG binding. In earlier studies, we demonstrated that amyotrophic lateral sclerosis (ALS) patient IgG can be taken up by motor neuron terminals and transported retrogradely to the cell body and can alter the function of neuromuscular synapses, such as increasing intracellular calcium and spontaneous transmitter release from motor axon terminals after passive transfer. In the present study, we examined whether FcγR‐mediated processes can contribute to these effects of ALS patient immunoglobulins. F(ab′)2 fragments (which lack the Fc portion) of ALS patient IgG were not taken up by motor axon terminals and were not retrogradely transported. Furthermore, in a genetically modified mouse lacking the γ subunit of the FcR, the uptake of whole ALS IgG and its ability to enhance intracellular calcium and acetylcholine release were markedly attenuated. These data suggest that FcγRs appear to participate in IgG uptake into motor neurons as well as IgG‐mediated increases in intracellular calcium and acetylcholine release from motor axon terminals. © 2002 Wiley‐Liss, Inc.
Neuroprotection of glial cell line‐derived neurotrophic factor in damaged spinal cords following contusive injury
Authors: Cheng Henrich , Wu Jey‐Pei , Tzeng Shun‐Fen 
Published: October 2002

AbstractGlial cell line‐derived neurotrophic factor (GDNF) acts as a potent survival factor for many neuronal populations, including spinal motoneurons, indicating the therapeutic promise of GDNF for neurological disorders. Injury to spinal cord (SCI) triggers processes destructive to ascending sensory and descending motor conduction and extends tissue loss, thereby leading to permanent behavioral dysfunction. In this study, we attempted to examine whether GDNF protects neurons from SCI and subsequently lessens locomotor deficit in SCI rats. We utilized the NYU weight‐drop device developed at New York University to induce spinal cord contusion at the T9–10 spinal segment. After SCI, GDNF was administrated into the cord 1–2 mm rostral and caudal to the epicenter. Animals receiving GDNF treatment showed significant improvement over phosphate‐buffered saline (PBS)‐treated controls on the Basso Beattie Bresnahan (BBB) locomotor rating scale (P < 0.01‐0.001). GDNF treatment increased the remaining neuronal fibers with calcitonin gene‐related peptide, neurofilament, and growth‐associated protein 43 immunoreactivity in injured spinal tissues compared with PBS‐treated controls. Moreover, treatment with GDNF caused approximately 50% cell survival in the contused spinal cord tissues. Examination of signal transduction triggered by GDNF indicated that GDNF injection transiently induced activation of the mitogen‐activated protein (MAP) kinase pathway in the spinal cord. Additionally, an up‐regulation of anti‐apoptotic Bcl‐2 levels in the contusive center of the damaged spinal cord was observed 24 hr post‐GDNF injection. Together our results show that GDNF exerts behavioral and anatomic neuroprotection following SCI. Additionally, GDNF‐activated MAP kinase and Bcl‐2 signaling may contribute to neuronal survival after spinal cord contusion. © 2002 Wiley‐Liss, Inc.
Neural (N‐) cadherin, a synaptic adhesion molecule, is induced in hippocampal mossy fiber axonal sprouts by seizure
Authors: Shan Weisong , Yoshida Mika , Wu Xi‐Ru , Huntley George W. , Colman David R. 
Published: October 2002

AbstractAberrant mossy fiber sprouting and synaptic reorganization are plastic responses in human temporal lobe epilepsy, and in pilocarpine‐induced epilepsy in rodents. Although the morphological features of the hippocampal epileptic reaction have been well documented, the molecular mechanisms underlying these structural changes are not understood. The classic cadherins, calcium‐dependent cell adhesion molecules, are known to function in development in neurite outgrowth, synapse formation, and stabilization. In pilocarpine‐induced status epilepticus, the expression of N‐cadherin mRNA was sharply upregulated and reached a maximum level (1‐ to 2.5‐fold) at 1– to 4 weeks postseizure in the granule cell layer and the pyramidal cell layer of CA3. N‐cadherin protein was correspondingly increased and became concentrated in the inner molecular layer of the dentate gyrus, consistent with the position of mossy fiber axonal sprouts. Moreover, N‐cadherin labeling was punctate; colocalized with definitive synaptic markers, and partially localized on polysialated forms of neural cell adhesion molecule (PSA‐NCAM)‐positive dendrites of granule cells in the inner molecular layer. Our findings show that N‐cadherin is likely to be a key factor in responsive synaptogenesis following status epilepticus, where it functions as a mediator of de novo synapse formation. © 2002 Wiley‐Liss, Inc.
Neurons overexpressing mutant presenilin‐1 are more sensitive to apoptosis induced by endoplasmic reticulum‐Golgi stress
Authors: Terro Faraj , Czech Christian , Esclaire Françoise , Elyaman Wassim , Yardin Catherine , Baclet Marie‐Claire , Touchet Nathalie , Tremp Günter , Pradier Laurent , Hugon Jacques 
Published: October 2002

AbstractMost early‐onset cases of familial Alzheimer's disease (FAD) are linked to mutations in two related genes, ps1 and ps2. FAD‐linked mutant PS1 alters proteolytic processing of the amyloid precursor protein and increases vulnerability to apoptosis induced by various cell stresses. In transfected cell lines, mutations in ps1 decrease the unfolded‐protein response (UPR), which is the response to the increased amounts of unfolded proteins that accumulate in the endoplamic reticulum (ER), indicating that these mutations may increase vulnerability to ER stress by altering the UPR signalling pathway. Here we report that, in primary cultured neurons from cortices of transgenic mice, overexpression of mutated PS1 (M146L mutation) but not PS1 wild‐type (wt) enhanced spontaneous neuronal apoptosis that involved oxidative stress and caspase activation. In PS1M146L cultures, neurons displaying immunoreactivity for human PS1 were threefold more vulnerable to spontaneous apoptosis than the overall neuronal population. In addition, PS1M146L transgenic neurons were more sensitive to apoptosis induced by various stresses, including two ER‐Golgi toxins, nordihydroguaiatric acid and brefeldin A (also known to induce UPR), as well as staurosporine. In contrast, PS1 wt transgenic neurons were resistant to apoptosis induced by Golgi‐ER toxins but displayed a comparable vulnerability to staurosporine. Our study demonstrates that, as previously reported, overexpression of FAD‐linked mutant PS1 enhances neuronal vulnerability to spontaneous and induced apoptosis. In addition, we show that this vulnerability was correlated with mutant PS1 protein expression and that PS1 wt overexpression selectively prevented ER‐Golgi stress‐induced apoptosis. These data indicate that PS1 interferes with a specific apoptotic pathway that results from a dysfunction of the ER‐Golgi compartment. © 2002 Wiley‐Liss, Inc.
Re‐evaluation of trends and changes in mean, maximum and minimum temperatures of Turkey for the period 1929–1999
Authors: Türkeş Murat , Sümer Utku M. , Demi̇r İsmai̇l 
Published: October 2002

AbstractMean, maximum and minimum surface air temperatures recorded at 70 climatological stations in Turkey during the period from 1929 to 1999 were analysed to reveal spatial and temporal patterns of long‐term trends, change points, significant warming (cooling) periods and linear trend rates per decade. Annual, winter and spring mean temperatures have tended to increase, particularly over the southern regions of Turkey, whereas summer and particularly autumn mean temperatures have decreased over the northern and continental inner regions. Annual, winter, spring and summer maximum temperatures have indicated a positive trend at many stations, except those in the Central Anatolia and Black Sea regions and partly in the Eastern Anatolia region. Autumn maximum temperatures, however, have decreased slightly over much of Turkey, except for the Aegean region. The majority of the urbanized and rapidly urbanizing stations in Turkey have been experiencing an apparent night‐time warming, especially during the warm and dry period of the year. Minimum temperatures have shown a statistically significant positive trend at 31 stations annually, 30 stations in spring and 33 stations in summer; most are significant at the 0.01 level. Winter and autumn minimum temperatures have indicated a general negative trend in some portions of the Marmara, Black Sea and Eastern Anatolia regions, whereas a general positive trend has been seen over much of Turkey along with the significant trends in the Mediterranean region of the country.Summer night‐time warming rates are generally larger than in spring and autumn night‐time temperatures. On the other hand, the night‐time warming rates of spring and summer are generally stronger than those in spring and summer daytime temperatures. By considering the marked increasing trends in spring, summer and annual minimum temperatures of urban stations, we have recognized that this is a clear and significant indication for the existence of a strong night‐time urban warming in Turkey. Copyright © 2002 Royal Meteorological Society.
Weichselian sediments at Foss‐Eikeland, Jæren (southwest Norway): sea‐level changes and glaciation history
Authors: Raunholm S. , Larsen E. , Sejrup H. P 
Published: October 2002

AbstractThe Jæren area in southwestern Norway has experienced great changes in sea‐levels and sedimentary environments during the Weichselian, and some of these changes are recorded at Foss‐Eikeland. Four diamictons interbedded with glaciomarine and glaciofluvial sediments are exposed in a large gravel pit situated above the post‐glacial marine limit. The interpretation of these sediments has implications for the history of both the inland ice and the Norwegian Channel Ice Stream. During a Middle Weichselian interstadial, a large glaciofluvial delta prograded into a shallow marine environment along the coast of Jæren. A minor glacial advance deposited a gravelly diamicton, and a glaciomarine diamicton was deposited during a following marine transgression. This subsequently was reworked by grounded ice, forming a well‐defined boulder pavement. The boulder pavement is followed by glaciomarine clay with a lower, laminated part and an upper part of sandy clay. The laminated clay probably was deposited under sea‐ice, whereas more open glaciomarine conditions prevailed during deposition of the upper part. The clay is intersected by clastic dykes protruding from the overlying, late Weichselian till. Preconsolidation values from the marine clay suggest an ice thickness of at least 500 m during the last glacial phase. The large variations in sea‐level probably are a combined effect of eustasy and glacio‐isostatic changes caused by an inland ice sheet and an ice stream in the Norwegian Channel. Copyright © 2002 John Wiley & Sons, Ltd.
Effects of controlled atmosphere (CA) storage on pectinmethylesterase (PME) activity and texture of ‘Rocha’ pears
Authors: Galvis Sánchez Andrea C , Morais Alcina M M B 
Published: October 2002

AbstractFirmness and pectinmethylesterase (PME) activity were evaluated in pears (cv Rocha) after 9 months of storage in controlled atmosphere (CA) followed by various periods of exposure to air at room temperature. The free calcium content was also evaluated in tissues. Fruit firmness decreased with increasing time of air exposure for all four different CA storage conditions tested. After 9 days of air exposure, fruits stored in 2% O2 + 1.5% CO2 were less firm than control fruits (stored in air) and showed higher PME activity. In spite of normal textural changes being observed with increasing time of exposure to air at room temperature, the underlying metabolism might have been affected by CA storage.© 2001 Society of Chemical Industry