bluuebunny/crossref_metadata_2025_split huggingface dataset:
Progressive elevations in AMPA and GABAA receptor levels in deafferented somatosensory cortex
Authors: He Hai‐yan , Rasmusson Douglas D. , Quinlan Elizabeth M. 
Published: August 2004

AbstractRestricted receptive fields (RFs), a hallmark of mature sensory systems, are actively maintained by a balance between ascending excitation and local inhibition in the cortex. Deafferentation disrupts this balance, allowing a sequence of changes in neuronal response properties that culminate in the reorganization of cortical RFs. To explore the molecular basis of deafferentation‐induced RF reorganization, we tracked changes in AMPA receptor (AMPAR), NMDA receptor (NMDAR) and GABAA receptor (GABAAR) levels in the deafferented somatosensory cortex of adult raccoons following single‐digit amputation. In synaptoneurosomes prepared from deafferented cortex, we observe a significant increase in AMPARs, but no change in NMDARs, 1–9 days post‐deafferentation, coincident with the appearance of new excitatory inputs and enlarged RFs. We observe a significant increase in GABAARs 2–7 weeks post‐deafferentation, coincident with a return of inhibitory input and shrinking RFs. These experience‐dependent changes in the levels of the major cortical ionotropic receptors were transient, returning to pre‐experimental baseline by ≥ 17 weeks post‐deafferentation, when RFs return to original size, but are remapped to different loci. This suggests that deafferentation‐induced cortical reorganization may be generated by activity‐dependent potentiation of weak excitatory synapses, followed by an increase in the strength of inhibitory synapses, resulting in finely tuned, remapped cortical RFs.
Metabolism of angiotensin II is required for its in vivo effect on dopamine release in the striatum of the rat
Authors: Stragier Bart , Sarre Sophie , Vanderheyden Patrick , Vauquelin Georges , Fournié‐Zaluski Marie‐Claude , Ebinger Guy , Michotte Yvette 
Published: August 2004

AbstractThe effect of angiotensin (Ang) IV, an inhibitor of insulin‐regulated aminopeptidase (IRAP), on extracellular dopamine levels in the striatum of freely moving rats was examined using in vivo microdialysis. The Ang IV was administered locally in the striatum through the microdialysis probe. A concentration‐dependent (10–100 µm) increase in extracellular striatal dopamine was observed. The effect of Ang II (10–100 µm), which has only a weak affinity for IRAP, was similar to that observed for Ang IV. The effects of both peptides could not be blocked by the AT1 antagonist candesartan (10 nm and 1 µm) nor by the AT2 antagonist S‐(+)‐1‐([4‐(dimethylamino)‐3‐methylphenyl]methyl)‐5‐(diphenyl‐acetyl)‐4,5,6,7‐tetrahydro‐1H‐amidazo(4,5‐c) pyridine‐6‐carboxylic acid (1 µm), suggesting that the observed effects are both AT1 and AT2 independent. The effect of Ang II could be blocked by the aminopeptidase‐A inhibitor (S)‐3‐amino‐4‐mercaptobutylsulphonic acid as well as the aminopeptidase‐N inhibitor 2‐amino‐4‐methylsulphonylbutane thiol, indicating that the effect of Ang II is mediated via metabolism into Ang IV. Other IRAP inhibitors, such as Divalinal‐Ang IV and LVV‐haemorphin‐7, had similar effects on extracellular dopamine levels as compared with Ang IV. We propose a role for IRAP as mediator for the effects of Ang IV and related peptides on extracellular dopamine levels in the striatum of the rat.
Permissive role of adenosine A2A receptors on metabotropic glutamate receptor 5 (mGluR5)‐mediated effects in the striatum
Authors: Domenici M. R. , Pepponi R. , Martire A. , Tebano M. T. , Potenza R. L. , Popoli P. 
Published: August 2004

AbstractThe metabotropic glutamate receptors 5 (mGlu5Rs) and the adenosine A2A receptors (A2ARs) have been reported to functionally interact in the striatum. The aim of the present work was to verify the hypothesis that the state of activation of A2A Rs could influence mGlu5R‐mediated effects in the striatum. In electrophysiological experiments (extracellular recording in rat corticostriatal slices), the ability of the selective mGlu5R agonist CHPG to potentiate the reduction of the field potential amplitude induced by NMDA was prevented not only by the selective mGlu5R antagonist MPEP, but also by the selective A2AR antagonist ZM 241385. Analogously, the application of CHPG potentiated NMDA‐induced toxicity (measured by LDH release) in cultured striatal neurons, an effect that was abolished by both MPEP and ZM 241385. Finally, the A2AR agonist CGS 21680 potentiated CHGP effects, an action that was reproduced and abolished, respectively, by forskolin (an activator of the cAMP/protein kinase A, PKA, pathway) and KT 5720 (a PKA inhibitor). The results indicate that A2ARs exert a permissive role on mGlu5R‐induced effects in the striatum. Such an interaction may represent an additional target for the development of therapeutic strategies towards striatal disorders.
Effect of valproic acid on serotonin‐2A receptor signaling in C6 glioma cells
Authors: Sullivan N. R. , Burke T. , Siafaka‐Kapadai A. , Javors M. , Hensler J. G. 
Published: August 2004

AbstractValproic acid (VPA), which has demonstrated efficacy in the treatment of bipolar disorder, has been shown to alter components of the phosphoinositide (PI) signaling cascade and to increase gene expression mediated by the transcription factor activator protein 1 (AP‐1). Central serotonin‐2A (5‐HT2A) receptors, which have been implicated in the pathophysiology of manic‐depressive illness, are coupled to PI hydrolysis. The promoter region of the 5‐HT2A receptor gene contains AP‐1 binding sites. We examined in C6 glioma cells the effect of VPA on 5‐HT2A receptor signaling. Treatment of cells with VPA (100 µg/mL) for 20 h, but not 1.5 h, resulted in an enhancement of 5‐HT2A receptor‐stimulated PI hydrolysis. This effect of 20‐h VPA exposure appeared not to be at the level of G protein or effector (i.e. phospholipase C: PLC) as inositol phosphate accumulation stimulated by aluminum fluoride or the PLC activator 2,4,6‐trimethyl‐N‐(m‐3‐trifluromethylphenyl) benzenesulfonamide was not increased. The number of 5‐HT2A receptors, as determined in saturation binding experiments using [3H]ketanserin, was increased by 20‐h VPA treatment, with no change in affinity (KD). Taken together, our data suggest that the increase in 5‐HT2A receptor‐mediated PI hydrolysis following 20‐h VPA exposure is not due to a general effect of VPA on this signaling cascade, but due to the up‐regulation of 5‐HT2A receptor number.
Validity and reliability of the revised convergence insufficiency symptom survey in adults
Authors: Rouse Michael W. , Borsting Eric J. , Lynn Mitchell G. , Scheiman Mitchell , Cotter Susan A. , Cooper Jeffrey , Kulp Marjean T. , London Richard , Wensveen Janice ,   Convergence Insufficiency Treatment Trial Group
Published: August 2004

AbstractPurpose:  To assess the validity and reliability of the revised Convergence Insufficiency Symptom Survey (CISS) in adults aged 19–30 years. The CISS was developed to be the primary outcome measure for studies evaluating various treatments for convergence insufficiency (CI).Methods:  CISS mean scores from adults with symptomatic CI and adults with normal binocular vision (NBV) were compared to assess the survey's validity. Adults with symptomatic CI were given the CISS twice to evaluate reliability, which was assessed using intraclass correlation coefficient (ICC) and 95% limits of agreement.Results:  Forty‐six adults with CI and 46 adults with NBV participated in the study. The mean CISS score for the CI group was 37.3 (S.D. = 9.3) and 11.0 (S.D. = 8.2) for the NBV group. These mean values were significantly different (p < 0.0001). Good discrimination (sensitivity = 97.8%, specificity = 87%) was obtained using a score of 21 or higher. For the CI group the ICC was 0.885 (95% CI of 0.798, 0.936) and the 95% limits of agreement were −9.0 to 7.6.Conclusions:  Adults with symptomatic CI had a significantly higher CISS score than adults with NBV. The results of the study demonstrate that the CISS is a valid and reliable instrument that can be used clinically or as an outcome measure for research studies of adults with CI.
A comparison of the ARK‐700A autokeratometer and Medmont E300 corneal topographer when measuring peripheral corneal curvature
Authors: González‐Méijome J. M. , Jorge J. , Queiros A. , Almeida J. B. , Parafita M. A. 
Published: August 2004

AbstractPurpose:  The purpose of this study was to evaluate if corneal topogometry measurements as taken with the ARK‐700A autokeratometer are comparable with those measured by the Medmont E300 videokeratoscope at corresponding locations.Methods:  Central and peripheral radius and eccentricity were measured in 122 right eyes of young normal subjects using autokeratometry and videokeratoscopy, obtained in a random order.Results:  Curvature measurements obtained with the ARK700A and Medmont E300 correlated well for the central cornea. Larger differences were observed between peripheral autokeratometry readings and the empirically determined corresponding locations with the videokeratoscope. Correlations between the instruments are inconsistent, resulting in unacceptable confidence intervals. Corneal eccentricity was significantly different between the instruments for the vertical (t = 2.4; p = 0.018) and for the horizontal meridians. In the first case, the difference between the averaged values was not clinically significant, but in the horizontal meridian the AK significantly overestimated eccentricity values (t = −11.5; p < 0.001) with differences which were clinically significant.Conclusions:  Central corneal curvature data obtained by ARK700A and Medmont E300 can be interchanged but the same is not true of peripheral determinations of corneal shape. ARK700A probably measures peripheral corneal shape within an elliptical region between 5 and 7 mm in diameter, with the major axis in the vertical meridian.
Relation between static and dynamic aspects of vergence, estimated with a subjective test using flashed dichoptic nonius lines
Authors: Jaschinski Wolfgang 
Published: August 2004

AbstractThe psychophysical technique for measuring vergence with dichoptic nonius lines was used to investigate dynamic responses to step vergence stimuli. Liquid crystal shutter glasses were operated with a cathode ray tube monitor to present convergent or divergent step stimuli of 32 min arc at t = 0. The resulting initial vergence response was estimated with nonius lines that appeared for 80 ms at a fixed delay of 400 ms after the vergence step stimulus. The vergence state reached 400 ms after the step depended on the vergence accuracy assumed before the step, i.e. baseline fixation disparity (FD). The following physiologically plausible results were found: (i) the amount of dynamic vergence changes within 400 ms tended to be negatively correlated between the convergent and divergent direction; (ii) subjects with a smaller convergent dynamic change had a steeper proximity–FD curve measured with static fusion targets as a function of viewing distance; (iii) FD was more eso or more exo depending on whether the vergence change was larger in the convergent or divergent direction respectively.
Influence of corneal asymmetry on the phakometric measurement of ocular surface alignment
Authors: Cervino A. , Uppal H. , Dunne M. C. M. 
Published: August 2004

AbstractPhakometric measurements of corneal and crystalline lens surface alignment are influenced by corneal asymmetry in which the corneal apex does not coincide with the limbal centre. The purpose of this study was to determine the horizontal separation (e) between these corneal landmarks. Measurements were made in 60 normal eyes (30 subjects) using the Orbscan IIz corneal analysis workstation. Our results show that both corneal landmarks typically coincide, so that e = 0, but that inter‐subject variations of about ±1 mm can be expected (so that the corneal apex may fall nasal or temporal to the visual axis). This suggests that no correction for corneal asymmetry is required when estimating average amounts of ocular alignment from samples of eyes but that the measurement of e is strongly recommended for measurements in individual eyes.
Comparison of aberrations in different types of progressive power lenses
Authors: Villegas Eloy A. , Artal Pablo 
Published: August 2004

AbstractRecently, computer numerically controlled machines have permitted the manufacture of progressive power lenses (PPLs) with different designs. However, the possible differences in optical performance among lens designs are not yet well established. In this work, the spatially resolved aberrations, at 20 relevant locations, of three PPLs with different designs were measured with a Hartmann–Shack wavefront sensor. The wavefront aberration (WA), its root mean square error (RMS) and the point‐spread function were obtained. Spatially resolved plots are shown for all aberrations, astigmatism alone, and for higher order aberrations. The average RMS of all zones is also compared, and the standard deviation is used as a parameter to evaluate the level of hard‐soft design. We find differences in the spatial distribution of the aberrations but not in the global RMS, indicating that current PPLs are rather similar to a waterbed, with the aberrations being the water: they can be moved but they cannot be eliminated.
Repeatability of the Waterloo Four‐Contrast LogMAR Visual Acuity chart and Near Vision Test card on a group of normal young adults
Authors: Cho Pauline , Woo George C. 
Published: August 2004

AbstractPurposes:  To investigate the repeatability of logMAR visual acuity (VA) with the Waterloo Four‐Contrast LogMAR Visual Acuity (FCLVA) chart and the Near Vision Test (NVT) card. The differences and agreements between near logMAR VA using horizontally‐ and vertically‐presented letters were also determined.Methods:  Visual acuity of one eye (55 subjects) was first assessed by using the FCLVA chart, comprising four charts of varying contrast, and then with the NVT card (comprising four charts of two contrasts and two presentations). Measurements were repeated after 3 or 4 weeks.Results:  No significant between‐visit differences were observed for any of the charts used. The repeatability coefficient for the distance 90, 60, 30 and 10% charts were 0.07, 0.11, 0.15 and 0.16 log units, respectively. The repeatability coefficients of the near vision charts were 0.06, 0.04 (high contrast), 0.11 and 0.10 (low contrast) log units. The agreements between horizontally‐ and vertically‐presented letters were good. The differences were similar to the repeatability coefficient of each chart.Conclusions:  The repeatability coefficient of the high contrast distance and near chart was about half a line. Repeatability coefficients increase with decreasing contrasts for both distance and near charts, with coefficients of one line or more for low contrast charts. Variabilities in both distance and near VA increase with decrease in contrast. The presentation of the letters does not affect near VA and the agreement between horizontally‐ and vertically‐presented letters (both high and low contrast) was within the repeatability coefficient of each chart.
Orbital development in Hong Kong Chinese subjects
Authors: Chau Anson , Fung Karl , Yip Lawrance , Yap Maurice 
Published: August 2004

AbstractThe purpose of this study was to examine the development of the orbit in Hong Kong Chinese subjects. Orbit volume was determined from magnetic resonance images of 81 subjects aged from 1 to 42 years old. Results show that orbit volume ranged from 11.56 to 25.50 cm3. In the first year of life, the mean orbit volume was 12.36 cm3. The orbit showed rapid growth in the first 3 years of life. From about 1–3 years old, the mean volume was 15.31 cm3. The orbit grew steadily to the age of 10 years. From age 11 to 15 years old, the mean volume was 20.24 cm3. Orbit growth levelled off at about 16 years of age with the mean volume at 21.00 cm3.
Spatial load factor in prediction of reading performance
Authors: Larter S. C. , Herse P. R. , Naduvilath T. J. , Dain S. J. 
Published: August 2004

AbstractThis study investigated whether there is a relationship between reading age and clinical optometric tests that have varying degrees of spatial loading in their design. Spatial loading in this context is the demand on the visual system to process information about the relative position and orientation of stimuli. A total of 112 children aged 8–11 years were assessed using saccadic eye movement and rapid naming tasks with varying spatial loads. All were subtests of Garzia's Developmental Eye Movement test and Liubinas’ SeeRite Reading Diagnostic Programme. Variability in load was achieved by comparing rapid naming of numerals vs the spatially loaded letters p, d, b, q; and by comparing the speed of reading numerals presented in increasingly complex arrays. Reading Age was assessed independently and results were analysed by multiple logistic regression. Spatially loaded naming tasks performed at speed exposed a Spatial Loading Factor which clearly differentiates children at risk with reading.
Pseudophakic accommodation with translation lenses – dual optic vs mono optic
Authors: Langenbucher Achim , Reese Sven , Jakob Christina , Seitz Berthold 
Published: August 2004

AbstractPurpose:  To investigate the pseudophakic accommodation effect in dual and mono optic translation accommodative intraocular lenses (AIOL) using linear matrix methods in the paraxial space.Methods:  Dual (anterior optic of power +32 D linked to a compensatory posterior optic of negative power) and mono lens power was determined in the non‐accommodated state using linear geometric optics based on the Gullstrand model eye. The position of the AIOL was calculated from a regression formula. Pseudophakic accommodation was assessed with three systems: (1) forward shift of the mono optic lens, (2) anterior translation of the anterior optic in the dual optic lens system with an unchanged position of the posterior minus lens and (3) symmetrical anterior and posterior translation of the anterior and posterior lens. The Gullstrand model eye was modified by changing the axial length (and proportionally changing the phakic anterior chamber depth) to investigate the accommodative effect in myopic and hyperopic eyes.Results:  The dual optic lens system (2) yields a nearly constant accommodation amplitude of 2.4–2.5 D mm−1 movement over the total range of axial lengths. The mono optic lens (1) provides a higher accommodative effect only in extremely short eyes (high refractive power of the lens), whereas for normal eyes (1.4–1.5 D mm−1 movement) and for long (myopic) eyes the accommodative effect is much less than the dual optic lens. The dual optic lens system under condition (3) yields less accommodation amplitude compared with the dual optic system under condition (2) over the total range of axial length but provides higher accommodation amplitude compared with the mono optic lens system (1) with axial lengths greater than 22.3 mm (lens power 25.5 D). In the accommodated state, with lens translation of 1 mm, the absolute value of the lateral magnification increases with the refractive power of the mono optic lens (1) and decreases in both dual optic lens systems (under conditions 2 and 3).Conclusions:  A mathematical strategy is presented for calculation of the accommodative effect of mono‐optic and dual optic AIOL. The dual optic lens yielded a nearly constant accommodation amplitude of about 2.4–2.5 D mm−1 translation, whereas the mono optic lens yielded an accommodative response of <2 D mm−1 translation in long myopic or normal eyes. Only in extremely short eyes is the accommodative amplitude of the mono‐optic lens higher than the dual optic lens.
Clinical characteristics of unilateral myopic anisometropia in a juvenile optometric practice population
Authors: Pointer Jonathan S. , Gilmartin Bernard 
Published: August 2004

AbstractPurpose:  A retrospective study of longitudinal case histories, undertaken to establish the clinical and statistical characteristics of unilateral myopic anisometropia (UMA) amongst the juvenile and adolescent population at an optometric practice, is reported. UMA was defined as that specific refractive state where an unequivocally myopic eye is paired with a ‘plano’ [spherical equivalent refraction, (SER) = ±0.25 Dioptres (D)] companion eye.Methods:  The clinical records of all patients aged <19 years on file at an established independent optometric practice were categorised as ‘myopic’ (SER ≤−0.50 D), ‘hypermetropic’ (≥+0.75 D) or ‘emmetropic’ (≥−0.37≤+0.62 D). Subsequently all juvenile patients matching the UMA criterion, together with a case‐matched group of bilaterally myopic individuals, were selected as the comparative study populations.Results:  A total of 14.4% (n = 21 of 146) of the juvenile myopic case histories were identified as cases of UMA. More than half of these UMA cases emerged between the ages of 11.5 and 13.5 years. There was a marked female gender bias. The linear gradient of the age‐related mean refractive trend in the myopic eye of the UMA population was not statistically significantly different (p > 0.1) to that fitted to the ametropic progression recorded in either eye of the case‐matched population of young bilateral myopes; uniquely the slope associated with the companion eye of UMA cases was statistically significantly (p < 0.025) less steep. Compared with bilateral myopes fewer cases of UMA required a refractive correction to relieve visual or asthenopic symptoms, and this initial correction was dispensed on average 1 year later (at age 12.7 years) in UMA patients.Conclusions:  Individuals identified as demonstrating clinically‐defined UMA can be considered as distinct but functionally normal cases on the continuum of human refractive error. However, any unilaterally‐acting determining factor(s) underlying the genesis of the condition remain obscure.
Influence of surround illumination on pupil size and contrast sensitivity
Authors: Vizmanos Juan G. , De La Fuente Isabel , Matesanz Beatriz M. , Aparicio Juan A. 
Published: August 2004

AbstractLighting plays a major role in contrast sensitivity (CS) measurements. Both the test and surround illumination influence the results although they are not usually considered in clinical practice. The effects of test luminance are well known, but the influence of surround luminance seems to be less investigated. This study aims to evaluate the differences in CS measured with two configurations of surround illumination typical of clinical practice; and to analyse the influence of the angular size of the target on pupil diameter for both surround luminances. An experimental arrangement was designed to measure CS with controlled illumination of both test and surround. An infrared pupillometer was also used to measure steady pupil size. A statistically significant increase of CS and a decrease of pupil size with higher surround illumination were found.