bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prevention of gliotic scar formation by NeuroGel™ allows partial endogenous repair of transected cat spinal cord
Authors: Woerly Stéphane , Doan Van Diep , Sosa Norma , de Vellis Jean , Espinosa‐Jeffrey Araceli 
Published: December 2003

AbstractSpinal cords of adult cats were transected and subsequently reconnected with the biocompatible porous poly (N‐[2‐hydroxypropyl] methacrylamide) hydrogel, NeuroGel™. Tissue repair was examined at various time points from 6–21 months postreconstructive surgery. We examined two typical phenomena, astrogliosis and scar formation, in spines reconstructed with the gel and compared them to those from transected non‐reconstructed spines. Confocal examination with double immunostaining for glial fibrillary acidic protein (GFAP) and myelin basic protein (MBP) showed that the interface formed between the hydrogel and the spine stumps did prevent scar formation and only a moderate gliosis was observed. The gel implant provided an adequate environment for growth of myelinated fibers and we saw angiogenesis within the gel. Electron microscopy showed that regenerating axons were myelinated by Schwann cells rather than oligodendrocytes. Moreover, the presence of the gel implant lead to a considerable reduction in damage to distal caudal portions of the spine as assessed by the presence of more intact myelinated fibers and a reduction of myelin degradation. Neurologic assessments of hindlimb movement at various times confirmed that spinal cord reconstruction was not only structural but also functional. We conclude that NeuroGel lead to functional recovery by providing a favorable substrate for regeneration of transected spinal cord, reducing glial scar formation and allowing angiogenesis. © 2003 Wiley‐Liss, Inc.
High‐level expression of Dok‐1 in neurons of the primate prefrontal cortex and hippocampus
Authors: Smith A. , Wang J. , Cheng C.M. , Zhou J. , Weickert C.S. , Bondy C.A. 
Published: December 2003

AbstractThe docking protein p62Dok‐1 (Dok‐1) has a central role in cell signaling mediated by a wide range of protein tyrosine kinases, including intrinsic membrane kinases, such as the insulin‐like growth factor‐1 (IGF‐1) receptor. To elucidate potential IGF signaling mechanisms, we used DNA array technology to investigate novel kinase targets expressed in the primate dorsolateral prefrontal cortex (DLPFC). Dok‐1 transcripts were among the most abundant found in this structure. Because Dok‐1 expression has not been characterized in brain, we evaluated its expression pattern using immunoblotting, in situ hybridization, and immunohistochemistry in the rhesus monkey prefrontal cortex and hippocampal formation. Dok‐1 antibodies identified a 62‐kDa band in lysates from the DLPFC, consistent with the known size for Dok‐1. In situ hybridization showed that Dok‐1 mRNA was expressed in all layers of the DLPFC and in all neuronal subregions of the hippocampal formation. Immunohistochemical analysis showed Dok‐1 immunoreactivity concentrated in pyramidal neurons of cortical layers IV–V and throughout Ammon's horn and in granule neurons of the dentate gyrus. Dok‐1 expression was also identified in endothelial cells of cerebral blood vessels. These expression patterns are very similar to those of the IGF‐1 receptor and suggest that Dok‐1 could be among the downstream targets of IGF signaling in areas of the primate brain involved in learning and memory. Published 2003 Wiley‐Liss, Inc.
Differential effects of zinc on glutamatergic and GABAergic neurotransmitter systems in the hippocampus
Authors: Takeda Atsushi , Minami Akira , Seki Yumiko , Oku Naoto 
Published: December 2003

AbstractApproximately 10% of total zinc in the brain exists in synaptic vesicles of glutamatergic neurons; however, the function of vesicular zinc is poorly understood. The presynaptic action of zinc against excitatory and inhibitory neurotransmission was studied in rat hippocampus using in vivo microdialysis. When the hippocampal CA3 region was perfused with 10–300 μM ZnCl2, the level of glutamate in the perfusate was decreased, whereas the level of γ‐aminobutyric acid (GABA) was increased. Chelation of endogenous zinc with CaEDTA increased the glutamate level in the perfusate but decreased the GABA level, suggesting that zinc released into the synaptic cleft acts differentially on glutamatergic and GABAergic neurons in the CA3 region. The increase of GABA level by zinc was antagonized by 2,3‐dioxo‐6‐nitro‐1,2.3,4‐tetrahydrobenzo(f)quinoxaline‐7‐sulphonamide (NBQX), an antagonist of α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionate (AMPA)/kainate receptors, but not affected by MK801, an antagonist of N‐methyl‐D‐aspartate (NMDA) receptors, and verapamil, a blocker of voltage‐dependent calcium channels. The present study suggests that zinc enhances GABA release via potentiation of AMPA/kainate receptors in the CA3 region, followed by a decrease in presynaptic glutamate release in the same region. Zinc seems to be an inhibitory neuromodulator of glutamate release. © 2003 Wiley‐Liss, Inc.
Axonal defects in mouse models of motoneuron disease
Authors: Jablonka Sibylle , Wiese Stefan , Sendtner Michael 
Published: December 2003

AbstractHuman motoneuron disease is characterized by loss of motor endplates, axonal degeneration, and cell death of motoneurons. The identification of the underlying gene defects for familial ALS, spinal muscular atrophy (SMA), and spinal muscular atrophy with respiratory distress (SMARD) has pointed to distinct pathophysiological mechanisms that are responsible for the various forms of the disease. Accumulating evidence from mouse models suggests that enhanced vulnerability and sensitivity to proapoptotic stimuli is only responsible for some but not all forms of motoneuron disease. Mechanisms that modulate microtubule assembly and the axonal transport machinery are defective in several spontaneous and ENU (ethylnitrososurea) mutagenized mouse models but also in patients with mutations in the p150 subunit of dynactin. Recent evidence suggests that axonal growth defects contribute significantly to the pathophysiology of spinal muscular atrophy. Reduced levels of the survival motoneuron protein that are responsible for SMA lead to disturbed RNA processing in motoneurons. This could also affect axonal transport of mRNAs for β‐actin and other proteins that play an essential role in axon growth and synaptic function. The local translation of specific proteins might be affected, because developing motoneurons contain ribosome‐like structures in distal axons and growth cones. Altogether, the evidence from these mouse models and the new genetic data from patients suggest that axon growth and maintenance involves a variety of mechanisms, including microtubule assembly and axonal transport of proteins and ribonucleoproteins (RNPs). Thus, defects in axon maintenance could play a leading role in the development of several forms of human motoneuron disease. © 2003 Wiley Periodicals, Inc. J Neurobiol 58: 272–286, 2004
What is the importance of multivesicular bodies in retrograde axonal transport in vivo?
Authors: Weible M. W. , Hendry I. A. 
Published: December 2003

AbstractNeurons with long axons have a unique problem in generating signaling cascades that are able to reach the nucleus after receptor activation by neurotrophins at the nerve terminal. The straightforward concept of receptor binding and local generation of 2nd second messenger cascades is too simplistic. In this review we will outline a mechanism that would enable the complex signals generated at the nerve terminal to be conveyed intact to the cell body. There are three different sites in the neuron where 2nd messenger proteins can interact with the signaling complex and be activated. Signaling cascades are initiated both at the nerve terminal and at the cell body when 2nd messengers are recruited to the plasma membrane by activated receptors. After receptor‐mediated endocytosis, 2nd messenger molecules continue to be recruited to the internalized vesicle; however, the mix of proteins differs in the nerve terminal and in the cell body. At the nerve terminal the activated pathways result in the formation of the neurotrophin signaling endosome, which includes molecules to be retrogradely transported to the cell body. When the retrograde neurotrophin signaling endosome reaches the cell body, it can recruit additional 2nd messenger molecules to finally generate the unique signal derived from the nerve terminal. We propose that the multivesicular body observed in vivo functions as an endosome carrier vehicle or retrosome. This retrosome enables the mix of signaling molecules recruited at the terminal to be transported intact to the cell body. This will allow the cell body to receive a snapshot of the events occurring at the nerve terminal at the time the retrosome is formed. © 2003 Wiley Periodicals, Inc. J Neurobiol 58: 230–243, 2004
Nondestructive testing and damage assessment of masonry structures
Authors: Schuller Michael P. 
Published: December 2003

AbstractRecent advances in nondestructive testing technology have led to mainstream use of several methods for evaluating masonry construction. Nondestructive approaches such as rebound hardness, stress wave transmission, impact‐echo, surface penetrating radar, tomographic imaging, and infrared thermography are useful for qualitative condition surveys as well as identification of internal features such as voids or areas of distress.In situtest methods are also available for determination of engineering properties. Flatjack methods are used to measure the state of compressive stress and compression response, masonry bed joint shear stress may be evaluated by anin situshear test, and mortar unit bond strength is tested by an adaptation of the bond wrench approach. Standardized methods exist for many of the evaluation approaches and related efforts are ongoing within ASTM and RILEM.
Helping students revise disruptive experientially supported ideas about thermodynamics: Computer visualizations and tactile models
Authors: Clark Douglas , Jorde Doris 
Published: December 2003

AbstractThis study analyzes the impact of an integrated sensory model within a thermal equilibrium visualization. We hypothesized that this intervention would not only help students revise their disruptive experientially supported ideas about why objects feel hot or cold, but also increase their understanding of thermal equilibrium. The analysis synthesizes test data and interviews to measure the impact of this strategy. Results show that students in the experimental tactile group significantly outperform their control group counterparts on posttests and delayed posttests, not only on tactile explanations, but also on thermal equilibrium explanations. Interview transcripts of experimental and control group students corroborate these findings. Discussion addresses improving the tactile model as well as application of the strategy to other science topics. The discussion also considers possible incorporation of actual kinetic or thermal haptic feedback to reinforce the current audio and visual feedback of the visualization. This research builds on the conceptual change literature about the nature and role of students' experientially supported ideas as well as our understanding of curriculum and visualization design to support students in learning about thermodynamics, a science topic on which students perform poorly as shown by the National Assessment of Educational Progress (NAEP) and Third International Mathematics and Science Study (TIMSS) studies. © 2003 Wiley Periodicals, Inc. J Res Sci Teach 41: 1–23, 2004
Violence exposure in real‐life, video games, television, movies, and the internet: is there desensitization?
Authors: Funk Jeanne B , Baldacci Heidi Bechtoldt , Pasold Tracie , Baumgardner Jennifer 
Published: December 2003

ABSTRACTIt is believed that repeated exposure to real‐life and to entertainment violence may alter cognitive, affective, and behavioral processes, possibly leading to desensitization. The goal of the present study was to determine if there are relationships between real‐life and media violence exposure and desensitization as reflected in related characteristics. One hundred fifty fourth and fifth graders completed measures of real‐life violence exposure, media violence exposure, empathy, and attitudes towards violence. Regression analyses indicated that only exposure to video game violence was associated with (lower) empathy. Both video game and movie violence exposure were associated with stronger proviolence attitudes. The active nature of playing video games, intense engagement, and the tendency to be translated into fantasy play may explain negative impact, though causality was not investigated in the present design. The samples’ relatively low exposure to real‐life violence may have limited the identification of relationships. Although difficult to quantify, desensitization to violence should be further studied using related characteristics as in the present study. Individual differences and causal relationships should also be examined.
Management of Neck Metastasis with Carotid Artery Involvement
Authors: Freeman Stephen B. , Hamaker Ronald C. , Borrowdale Richard B. , Huntley Tod C. 
Published: December 2003

AbstractObjectives To demonstrate aggressive management of neck metastasis adherent to the internal or common carotid artery using sound oncologic principles while minimizing the significant risk of complications.Study Design Our 13 year experience of treating patients with recurrent or residual neck metastasis adherent to the internal or common carotid artery was retrospectively reviewed.Methods Angiography was used in patients who demonstrated fixation of the carotid artery on examination or imaging, followed by balloon test occlusion and single photon emission computer tomography (SPECT) scanning. The majority of carotid resections were reconstructed with a vein graft, especially if there was insufficient collateral cerebral circulation. Radical resection of the soft tissue including the carotid artery was performed followed by 15 to 20 Gray of electron beam delivered directly to the deep tissue. More recently, the carotid has been permanently occluded preoperatively, if possible. The assessment of the cerebral circulation and management of the carotid artery were analyzed as was survival, site of recurrence, and complications.Results Fifty‐eight charts were reviewed. The majority of patients (41) had their carotid artery reconstructed at time of resection, and the remaining had either the artery ligated or permanently occluded preoperatively. Strokes occurred in 11 patients. The median disease‐specific survival was 12 months, with 24% of patients dying from distant metastasis.Conclusions The high risk of complications, loss of life's quality, and mortality must be balanced against the natural history of the disease if left untreated. The decision is a heavy burden for the patient, family, and head and neck surgeon.
Time Scale for Periosteal Readhesion After Brow Lift
Authors: Kim Jenny C. , Downs J. Crawford , Azuola Maria E. , Graham H. Devon 
Published: December 2003

AbstractObjectives/HypothesisThe objective was to determine the time interval after brow lift required to achieve periosteal repeat adhesion to the skull with preoperative strength.Study DesignRandomized prospective analysis of variance with repeated measures.MethodsTwenty‐one New Zealand white rabbits, each serving as its own control, underwent subperiosteal elevation on one side of the skull. The elevated periosteum was lifted and fixed to a resorbable screw, and the contralateral periosteum was left untouched. Adhesion characteristics were subsequently examined at postoperative days 5, 6, 7, 8, 10, 12, and 17. Seven subjects were assessed histologically to determine attachment of periosteum to underlying bone. Fourteen subjects underwent biomechanical analysis of the bone‐periosteum interface using the following three measures of periosteal repeat adhesion strength: ultimate shear strength, shear stiffness, and shear energy.ResultsBlinded histological analysis showed a qualitative increase in the number of markers of periosteal healing on days 8 to 12 for the operated sides. Analysis of ultimate shear strength and shear stiffness demonstrated a significant relationship to postoperative day (P< .001). The ultimate shear strength and shear stiffness of the operated side approached that of the nonoperated side by postoperative days 12 and 8, respectively. Shear energy was significantly lower for all time points on the operated side as compared with the control (P< .02).ConclusionPeriosteal readhesion after surgical elevation approaches preoperative strength by the twelfth postoperative day.
Electrophysiologic Effects of Placing Cochlear Implant Electrodes in a Perimodiolar Position in Young Children
Authors: Wackym Phillip A. , Firszt Jill B. , Gaggl Wolfgang , Runge‐Samuelson Christina L. , Reeder Ruth M. , Raulie Jennifer C. 
Published: December 2003

AbstractObjective The purpose of this study was to intraoperatively record the electrically evoked auditory brainstem response (EABR) before and after placement of the electrode positioning system (EPS) (CII Bionic Ear with HiFocus I cochlear implant electrode array) as well as before and after stylet removal (Nucleus Contour cochlear implant electrode array). It was hypothesized that physiologic changes would occur after perimodiolar positioning of the electrode array and these changes would be evident from the EABR recordings.Study Design Consecutive young (11–36 month old) pediatric cochlear implant recipients (n = 17) had intraoperative EABRs recorded from three intracochlear electrodes that represented apical, medial, and basal locations. Wave V amplitudes and thresholds were studied relative to electrode location and pre‐ versus postperimodiolar positioning. These evoked potential measures were analyzed for statistical significance.Setting Tertiary referral children's hospital/medical college.Results Wave V thresholds of the EABR were lower, and amplitudes were larger after perimodiolar positioning, although the changes were dependent on electrode location and implant design. Statistically significant decreases in EABR wave V threshold and increases in suprathreshold wave V amplitude were found for the basal electrode for the CII Bionic Ear HiFocus I and for the apical electrode for the Nucleus Contour.Conclusions Placement of either the CII Bionic Ear HiFocus I or Nucleus Contour cochlear implant electrode array in the perimodiolar position in young children resulted in less electrical current necessary to stimulate the auditory system. Changes in electrophysiologic thresholds and amplitudes, measured with EABR, indicate that the electrode array is placed closer to the modiolus with both electrode designs.
Functional Magnetic Resonance Imaging of Activation in Subcortical Auditory Pathway
Authors: Yetkin F. Zerrin , Roland Peter S. , Mendelsohn Dianne B. , Purdy Phillip D. 
Published: December 2003

AbstractObjectives Functional magnetic resonance imaging (fMRI) has been used to investigate activation of the auditory cortex; however, assessment of activation in the subcortical auditory pathway has been challenging. The aim of this study was to examine neural correlates of cortical and subcortical auditory activation evoked by pure‐tone stimulus using silent fMRI.Study Design Prospective analysisMethods Seventeen normal‐hearing volunteers (7 male, 10 female; age range, 14–37 yrs) underwent silent fMRI. An audiometer was used to deliver pure tones of 1000 Hz to the left ear. Pure tones were presented at hearing thresholds determined in the scanner. Brain regions showing increased activation during pure‐tone stimulus presentation were mapped and auditory activations exceeding P < .001 were included in the analysis.Results Pure‐tone stimuli evoked bilateral activation in cortical regions of the transverse and superior temporal gyri and the planum temporale. Activation in subcortical structures included the medial geniculate body, inferior colliculus, lateral lemniscus, superior olivary complex, and cochlear nucleus.Conclusions Silent functional magnetic resonance imaging findings documented the feasibility of detecting activation elicited by pure tone along the cortical and subcortical auditory pathway. The use of this technique in the assessment of disorders with auditory dysfunction merits further investigation.
Epidermal Growth Factor Receptor in Undifferentiated Carcinoma of the Nasopharynx
Authors: Leong Jern‐Lin , Loh Kwok Seng , Putti Thomas Choudhary , Goh Boon Cher , Tan Luke Kim Siang 
Published: December 2003

AbstractObjectives To determine the expression levels of epidermal growth factor receptor (EGFR) and its prognostic value in undifferentiated carcinoma (UC) of the nasopharynx.Study Design A prospective study of 75 patients diagnosed with UC over a 4‐year period in a tertiary care hospital.Materials and Methods Postnasal space biopsies were obtained and processed, and immunohistochemical staining was performed. The over‐expression of EGFR was measured, and the expression levels were statistically analyzed with the clinical and pathologic variables. Disease‐free and overall survival analyses were performed.Results There were 62 (82.7%) specimens that showed over‐expression of EGFR levels. Over‐expression of EGFR correlated significantly only with primary tumor size (P = .007). Age, sex, positive smoking and family history, presence of nodal metastasis, distant metastasis, and Epstein‐Barr virus serology titers were not significantly correlated with over‐expression of EGFR. Both 54‐month disease‐free and 56‐month overall survivals were not associated with EGFR over‐expression.Conclusion The frequency of over‐expression of EGFR in UC is similar to other squamous cell carcinoma (SCC) of the head and neck region. Only primary tumor size is independently correlated with over‐expression of EGFR. EGFR over‐expression does not affect disease‐free and overall survival.
The Impact of Severe Acute Respiratory Syndrome on Otorhinolaryngological Services at The Prince of Wales Hospital in Hong Kong
Authors: Vlantis Alexander C. , Tsang Raymond K. Y. , Wong Duncan K. K. , Woo John K. S. , van Hasselt C. Andrew 
Published: December 2003

AbstractObjectives/Hypothesis The objective was to describe the impact of severe acute respiratory syndrome (SARS) on the services of the division of otorhinolaryngology—head and neck surgery at an academic tertiary referral hospital in Hong Kong.Study Design Descriptive.Methods Records of general and subspecialty outpatient attendance, ward admissions, ward bed occupancy, and elective and emergency surgery were obtained for the period since the SARS outbreak and for an equivalent period before the outbreak. The changes in these parameters were determined against the background of new SARS cases.Results Since the outbreak of SARS in March 2003, the weekly outpatient clinic attendance has declined by 59%, the number of operations performed by 79%, the average ward bed occupancy rate by 79% and the daily admission rate by 84%. A dramatic increase of 300% in the number of patients defaulting on their outpatient appointments was recorded.Conclusion The substantial decrease in otorhinolaryngological services at an academic tertiary referral hospital in Hong Kong has been multifaceted. The decrease in attendance at the outpatient clinics reflects the increased number of patients defaulting on their appointments. Nonessential elective surgery was suspended soon after the outbreak, accounting for the decrease in the number of surgical procedures performed and partially for the decrease in ward bed occupancy and ward admissions. The temporary closure of the accident and emergency department contributed to the decrease in ward admissions and emergency surgical procedures. The reduced service offered by the hospital is having an impact on the quality of care available to patients with non–life‐threatening otorhinolaryngological conditions.